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231 Cards in this Set

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"right-to-left" shunt characteristics
-In general, divert non-oxygenated blood away from the pulmonary circuit and into the systemic circulation, reducing the oxygen saturation of the arterial blood. -results in cyanosis (a bluish discoloration of the skin due to accumulation of reduced hemoglobin in capillary beds and seen most readily around the lips and nailbeds) at or soon after birth
-necessary for fetus since lungs are not developed
LEFT-TO-RIGHT SHUNTS characteristics
-divert oxygenated blood from the systemic circulation (including the myocardial circulation) and into the pulmonary circulation, depriving the systemic tissues of oxygen
-Additionally, the excess blood flowing through the pulmonary circulation produces a pulmonary hypertension
OBSTRUCTIVE DISORDERS (coarctation of the aorta, valvular stenosis) - characteristics
These are physical barriers to blood flow and generally do not cause cyanosis. They do, however, lead to hemodynamic disturbances.
Arteriosclerosis characteristics
-encompasses a group of vascular disorders which are characterized by thickening and loss of elasticity of arterial walls
-most common type of arteriosclerosis is atherosclerosis, and these two terms are often used interchangeably
-Atherosclerosis is a slow progressive disease of the large elastic and large and medium sized muscular arteries characterized by the formation of atherosclerotic plaques
-increasingly clinically significant with age
risk factors for atherosclerosis
-Major risk factors include hyperlipidemia, hypertension, cigarette smoking, and diabetes mellitus. -Minor risk factors are physical inactivity, stress and behavior patterns, obesity, and long term oral contraceptive use
-non-alterable factors include age, sex, genetic predisposition, etc.
ROLE OF PLASMA LIPIDS
-cholesterol is vital for the synthesis of cellular membranes, steroid hormones, and bile acids. 93% of the body cholesterol is therefore located intracellularly to provide substrate for these metabolic functions while 7% is circulating as plasma cholesterol.
lipoproteins formation
Cholesterol and triglycerides are insoluble in blood and are, therefore, complexed with a variety of specific proteins to form soluble lipoproteins
chylomicrons fxn
primarily transport dietary triglycerides and, to a lesser extent, dietary cholesterol;
beta lipoproteins ("low density lipoprotein", LDL) fxns
primarily transport endogenous cholesterol and are the major plasma cholesterol carriers
pre-beta lipoproteins ("very low density lipoprotein", VLDL) fxns
primarily transport endogenously produced hepatic triglycerides to adipose and muscle tissue
alpha lipoproteins ("high density lipoprotein", HDL) fxns
-primarily transport endogenous cholesterol acquired from extrahepatic tissues and returns it to the liver
-HDL can extract cholesterol from the cell and transfer it to the liver where it can then be excreted.
PLASMA CLEARANCE OF LDL- receptor pathway
-Liver cells have specific cell surface receptors that bind LDL
-LDL is cleared from the plasma by incorporation into the liver cell where it can then be can be excreted into the bile
-In cells outside of the liver, excess free cholesterol is stored in the cytoplasm but there is only a limited storage capacity
high levels of HDL and LDL significance
Elevated levels of plasma LDL are directly related to the development of clinically significant atherosclerosis while elevated levels of HDL seem to have a protective effect
PHAGOCYTIC (RECEPTOR-INDEPENDENT) PATHWAY characteristics
-Cells of the monocyte/macrophage phagocytic system have receptors for "modified" LDL and normally clears approximately one third of the plasma LDL
-cannot regulate the amount of cholesterol taken into the cell and in conditions of high levels of plasma LDL the cells become overstuffed and lead to the development of xanthomas
ETIOLOGY OF HYPERLIPIDEMIA characteristics
Certain types occur as a result of inherited genetic defects and are among the most frequently encountered inherited disorders
-majority are due to dietary excess or a combination of dietary and genetic factors
-major contributors to hypercholesterolemia are excessive caloric intake, excessive dietary cholesterol, and saturated fatty acids.
atherosclerotic RISK ASSESSMENT- TOTAL CHOLESTEROL (TC)
-Initial screening for atherosclerotic risk involves measurement of total serum cholesterol
-middle aged adults (>40), a value between 200 mg/dl and 240 mg/dl is considered borderline and overt hypercholesterolemia is considered to be a plasma cholesterol >240 mg/dl
atherosclerotic RISK ASSESSMENT- TC/HDL-C RATIO
If the total cholesterol levels are high, the cholesterol associated with HDL (HDL-C) can be measured in the laboratory. Since HDL-C has a protective effect, the lower the ratio the less risk for developing coronary artery disease. A "good" ratio would be 4:1 or less.
atherosclerotic RISK ASSESSMENT- LDL-C/HDL-C RATIO
This can also be a useful ratio and gives much the same information as the TC/HDL-C ratio.
atherosclerotic RISK ASSESSMENT- PLASMA TOTAL HOMOCYSTEINE LEVEL
-increased plasma total homocysteine level is an independent risk factor for atherosclerotic disease whether or not serum cholesterol is elevated
-homocysteine impairs endothelial function
-Since normal homocysteine metabolism requires vit. B12, vit. B6 and folic acid, deficiencies of these vitamins lead to elevated homocysteine levels.
atherosclerotic RISK ASSESSMENT- CHLAMYDIA PNEUMONIAE AND CYTOMEGALOVIRUS INFECTIONS
-These microbiologic agents have been shown to confer an increased risk of developing clinically significant atherosclerosis
-common infections (approximately 50% of middle-aged adults), there must also be other genetic or environmental factors at play that place these individuals at increased risk
PATHOGENESIS atherosclerosis
-response to vascular endothelial damage
-injury to the endothelium results in an increased permeability of the vessel to plasma constituents at the site of injury and LDL and VLDL are able to penetrate under the endothelium
-Uncontrolled intracytoplasmic accumulation eventually cause cell death and rupture leading to the formation of non-reversible atherosclerotic plaques
atherosclerosis morphology- fatty streaks
-probably reversible lesions and may or may not represent precursor lesions of adult plaques
-appear as multiple, essentially flat yellow streaks on the inner surface of vessels
atherosclerosis morphology- ATHEROSCLEROTIC PLAQUES
-appear as multifocal asymmetric elevations of the vessel lining
-hard and soft plaque but most have a firm fibrous cap overlying a softer core of atheromatous and necrotic debris
-tend to be most severe in the abdominal aorta, particularly in areas of vascular branching
-"Routine" plaques may evolve into clinically significant "complicated" plaques when there is associated thrombus formation, ulceration of the fibrous cap, hemorrhage into the plaque, dystrophic calcification, or weakening of the vessel wall
atherosclerosis clinical significance
-Generally, this is related to the physical obstruction to blood flow, the risk of thrombosis, and alteration of the normal activity of endothelial cells
-Although atherosclerosis can occur in any of the large and medium sized arteries, clinical symptoms are generally related to the hemodynamic effects on the heart, brain, kidney, small bowel, and lower extremities
ISCHEMIC HEART DISEASE (IHD) caused by
-IHD results from an imbalance between the availability of oxygen and the metabolic demand of the heart
-availability of oxygen may be affected by reduced coronary flow, increased metabolic demand, or decreased saturated hemoglobin availability.
ACUTE ISCHEMIC HEART DISEASE types
Clinically, acute IHD is manifested as angina pectoris, the more severe myocardial infarct, or occasionally sudden cardiac death
angina pectoris characteristics
-not a disease in itself but a symptom complex manifested by paroxysmal attacks of substernal or precordial chest discomfort often described as a pressure, constriction, or heaviness which may extend into the neck, left jaw, left shoulder, and left arm
-often induced or aggravated by cold weather, exercise, heavy meals, cigarette smoking, or emotional stress. -discomfort arises from a temporary inability to supply sufficient oxygen to the heart muscles, i.e. myocardial ischemia and hypoxia.
ACUTE MYOCARDIAL INFARCTION characteristics
-due to irreversible myocardial damage resulting from inadequate oxygenation of myocardial fibers
-majority of cases show severe underlying coronary artery disease and the myocardial injury, is due either to occluded or markedly reduced blood flow rather than increased metabolic demand
-risk of acute thrombosis depends, therefore, more on the biology of the plaque than it does on the size
myocardial infarct distribution
Most infarcts occur in the distribution of the left anterior descending coronary artery (i.e. the anterior interventricular septum and the anterior and lateral left ventricular wall).
myocardial infarct morphology
-No changes grossly visible until about one day after the infarct when the affected area becomes pale. -typical acute inflammatory response to the damaged myocardial cells followed by the appearance of granulation tissue and eventual scar formation
myocardial infarct lab findings
-When the myocardial cells die, they release cytoplasmic enzymes into the circulation which can then be measured in the laboratory
-elevation of serum CPK during the first 24 hours but this will return to normal in 3-5 days
-slower rise in serum LDH which persists 7-12 day
-troponin-I (cTn-I) is the most cardiac specific
myocardial infarct complications
include cardiac arrhythmias (90%), left ventricular dysfunction, mural thrombosis and embolization, rupture of left ventricular wall, and ventricular aneurysms
myocardial infarct modes of intervention
(1) Thrombolytic therapy
(2) Angioplasty
(3) Coronary bypass
myocardial infarct SUDDEN CARDIAC DEATH characteristics
(< 1 hour after onset of symptoms) - This is usually associated with fatal arrhythmias precipitated by an acute ischemic event. Most patients (90%) have severe coronary disease and 50% have evidence of old infarcts but only rarely acute infarcts. Sudden cardiac death, however, can occur without clinical or morphologic evidence of coronary disease.
CHRONIC ISCHEMIC HEART DISEASE characteristics
-Asymptomatic, slow, progressive atherosclerotic coronary disease may become manifested by the insidious onset of congestive heart failure as the cardiac reserve is slowly depleted
-characterized by diffuse myocardial atrophy, spotty loss of myocardial cells (myocytolysis), diffuse fibrosis, and possible scarring from previous infarcts.
Valvular stenosis definition
-implies failure of a valve to open properly thereby creating obstruction to the forward flow of blood. -Acquired stenosis is almost always due to a primary abnormality of the cusps or leaflets
valvular insufficiency definition
-implies an inability of a valve to close properly and thereby allows for the backward flow of blood
-can be due to intrinsic valve disease or damage to the valve's supporting structures
RHEUMATIC HEART DISEASE characteristics
-consequence of cardiac involvement in a systemic inflammatory disease, rheumatic fever
-may follow an infection by ß-hemolytic streptococci
-migratory polyarthritis, carditis, erythema marginatum, subcutaneous nodules, and Sydenham chorea
-more common in children
-Symptoms are due to immunologic cross reactivity between streptococcal antigens and host tissue antigens
pancarditis definition
Rheumatic fever induces an inflammatory reaction in all layers of the heart
pericarditis may cause
Acute fibrinous inflammation of the pericardium may cause a friction rub on auscultatio
MYOCARDITIS may cause
Focal necrosis and inflammation of the myocardium may lead to cardiac arrhythmias
endocarditis characteristics
-most crippling and destructive aspect of rheumatic heart disease
-Healing of the inflammation that occurs in the heart valves results in fibrous, thickened, rigid valves whose leaflets or cusps become fused and calcified
-leads to valvular stenosis and insufficiency (primarily involving the mitral valve and, in some cases, the aortic valve)
RHEUMATIC HEART DISEASE complications
-Despite prompt therapy and prophylaxis, the first attack may eventually result in severe damage to the heart valves
-Causes of death include cardiac failure, mural thrombosis and embolization, and bacterial endocarditis
CALCIFIC AORTIC STENOSIS characteristics
-Calcified nodules develop and obstruct the flow of blood through the valve
-Symptoms (dyspnea, angina, syncope, etc.) generally are referable to left heart failure or inadequate cardiac output and once they appear, median survival is only 2-3 years unless the valve is replaced
-in elderly more common, it is
MITRAL VALVE PROLAPSE characteristics
-characterized by enlarged mitral leaflets and/or elongated chordae
-Eventually, possibly from long standing trauma, the leaflets thicken as do the chordae (which may also fuse)
-majority of patients are asymptomatic but death can result from complications of infective endocarditis, from chronic congestive failure, from chordal rupture or from arrhythmia
INFECTIVE ENDOCARDITIS definition
-involves the development of friable septic vegetations (thrombi with embedded bacteria) on heart valves or endocardial surfaces
-two clinical categories emerge (acute and subacute)
ACUTE ENDOCARDITIS (ABE) characteristics
-virulent organisms like Staphylococcus aureus can directly damage the heart valves and promote thrombus formation
-damage the endocardial surface which promotes thrombus formation and the bacterial colonies get entrapped within the developing thrombus
-abrupt onset of high fever, shaking chills, and profound weakness. Embolic phenomena and cardiac decompensation occur early. As many as 70% of these patients may die as a result of heart failure, emboli, arrhythmias, or uncontrolled sepsis.
SUBACUTE ENDOCARDITIS (SBE) characteristics
-hearts characteristically have some underlying disease with either valvular or congenital abnormalities that predisposes to thrombus formation on the endocardial surfaces
-onset is usually insidious with progressive weakness, weight loss, anemia, fever, occasional night sweats
HYPERTENSIVE HEART DISEASE (blood pressure > 140/90) characteristics
-heart responds to a pressure overload by concentric hypertrophy of the ventricle
-In absence of any other abnormality that might produce left ventricular hypertrophy (i.e. valve disease), this is identifying hallmark of hypertension
-heart begins to decompensate and, as decompensation occurs, the ventricle dilates (increasing heart size) and obscures the hypertrophic changes
-asymptomatic until cardiac decompensation intervenes and there is an insidious onset of symptoms of left heart failure
Untreated hypertension results in
death due to heart failure, stroke, renovascular disease and/or vascular complications
MYOCARDITIS characteristics
-any inflammatory condition (microbiologic, immunologic, etc.) that involves the myocardium
-Over half of the cases are caused by viruses and are most frequently seen in infants, pregnant women, and immunosuppressed patients
-clinical manifestations usually include tachycardia, arrhythmias, low grade fever, dyspnea and malaise
CARDIOMYOPATHY characteristics
-refers to non-inflammatory disorders of the myocardium
-clinical and pathologic patterns generally fall into one of three categories
DILATED (CONGESTIVE) CARDIOMYOPATHY characteristics
-may simply represent a common end point of a variety of previously undiagnosed cardiac diseases and can occur at any age
-Some are of known cause (alcoholic, familial, peripartum, nutritional, and post-infectious cardiomyopathies), but the large majority must be classified as idiopathic.
DILATED (CONGESTIVE) CARDIOMYOPATHY morphology
-characterized by dilatation and hypertrophy of all chambers of the heart with impairment of ventricular contraction and congestive heart failure
-Due to poor contractility, mural thrombi are prone to develop (most frequently in the left ventricle)
DILATED (CONGESTIVE) CARDIOMYOPATHY clinical presentation
Patients generally present with signs and symptoms of congestive heart failure. Progressive heart failure usually culminates in death unless patients first succumb to arrhythmias or the effects of systemic emboli
HYPERTROPHIC (OBSTRUCTIVE) CARDIOMYOPATHY characteristics
-also been referred to as asymmetric septal hypertrophy (ASH) and idiopathic hypertrophic subaortic stenosis (IHSS)
-probably represents an inherited condition (particularly in patients with a family history of sudden unexplained deaths).
HYPERTROPHIC (OBSTRUCTIVE) CARDIOMYOPATHY morphology
dilated atria, disproportional hypertrophy of the interventricular septum with myofiber disarray, decreased ventricular volume, mitral valve thickening, endocardial thickening of left ventricular outflow tract, and thickening of the intramural arterioles.
HYPERTROPHIC (OBSTRUCTIVE) CARDIOMYOPATHY clinical appearance
-asymmetrically hypertrophied septum and left ventricle may or may not result in signs and symptoms of obstruction of the left ventricular outflow
-If the septal hypertrophy is more prominent in the lower portion of the IVS, obstructive symptoms are less likely to occur than if the hypertrophy is higher in the septal wall
RESTRICTIVE/INFILTRATIVE CARDIOMYOPATHIES characteristics
-rare conditions characterized by restriction of ventricular filling
-Although the pathologic process is different, the clinical signs and symptoms are essentially the same as dilated cardiomyopathy
ACUTE PERICARDITIS characteristics
-generally due to infectious organisms or irritation of the pericardium and can lead to the accumulation of either fibrinous, serous, purulent, or hemorrhagic fluid
-Clinical significance depends on the type of fluid that accumulates and the rapidity with which it accumulates
CHRONIC PERICARDITIS can cause
may lead to obliteration of the pericardial sac which can interfere with the ability of the heart to contract normally and thereby interfere with cardiac output
AORTIC ANEURYSMS- abdominal characteristics
-often result of atherosclerotic weakening of the aortic wall
-generally occur in middle-aged to elderly males, half of whom are hypertensive
-majority occur in the distal abdominal aorta where atherosclerosis tends to be most severe
-symptoms slowly develop until they become large or until they rupture
AORTIC ANEURYSMS- thoracic characteristics
-Due to their location, clinical symptoms are more common with thoracic aneurysms
-Compression of lungs, trachea or bronchi may lead to respiratory problems; compression of the esophagus may lead to dysphagia; compression of the recurrent laryngeal nerve may lead to hoarseness; and erosion of bony structures may lead to pain.
CYSTIC MEDIAL NECROSIS characteristics
-responsible for the majority of thoracic aortic aneurysms
-chronic degenerative process of unknown etiology that results in focal destruction of the media of the thoracic aorta
-most likely due to a metabolic defect in the synthesis of collagen and elastin
-frequently associated with Marfan syndrome
SYPHILIS (luetic) characteristics
-consequence of tertiary syphilis, these aneurysms are generally limited to the ascending aorta and aortic arch
-Inflammation caused by the organism produces weakening of the aortic wall thereby allowing aneurysm formation
-Most patient’s die of heart failure, but the aneurysm may rupture.
AORTIC DISSECTION characteristics
-more common than rupture of atherosclerotic aneurysms and involves tearing of the inner lining of the aorta with dissection of blood into and along the wall
-present as a "tearing" pain in anterior chest radiating into and down the back
PERIPHERAL VASCULAR DISEASE characteristics
-occurs as a result of gradual buildup of atherosclerotic plaques (often as a complication of diabetes) in peripheral arteries, most frequently the arteries to the legs
-As the arteries are narrowed by atherosclerosis, there will be eventual ulceration and gangrenous necrosis of the skin and underlying tissues
VARICOSE VEINS characteristics
-A varix refers to any venous dilatation that results from chronic elevation of intravascular hydrostatic pressure
-overall effect is to create chronic soft tissue edema, venous stasis, and thrombosis
-skin may develop stasis dermatitis and chronic ulcerations
pores of Kohn fxn
allow communication between adjacent alveolar spaces
acinus definition
represents the functional gas exchange area of the lung and is composed of a respiratory bronchiole and its branching structures
respiratory tract defense mechanisms
-Large particulate matter is filtered by nasal hairs or trapped in the oropharynx
-Smaller particles are trapped in the bronchial mucous blanket or the bronchiolar watery secretions rich in lysozyme and secretory IgA
-Particles that are 1-5μ in size are accessible to the terminal airways and alveoli where they are phagocytized by the alveolar macrophages
Ventilation definition
the movement and distribution of air within the tracheobronchial system
diffusion definition
movement of O2 and CO2 between the alveolar space and the capillary blood
perfusion definition
the flow and distribution of blood within the pulmonary vascular bed
OBSTRUCTIVE PULMONARY DISEASES characteristics
-results from the narrowing or obstruction of the tracheobronchial tree or from destruction of the pulmonary parenchyma
-results in an increased compliance (i.e. stretchability while inhaling) of the lungs but a decreased elastic recoil (i.e. compressability while exhaling)
CHRONIC BRONCHITIS ("blue bloaters") characteristics
-characterized by excessive mucous secretion within the bronchial tree than cannot be explained by either a specific infection or by infiltrative disease
-defined as a chronic cough with sputum production for at least three months of the year in at least two consecutive years.
-cigarettes major cause
-major pathophysiologic disruption is large airway obstruction
chronic bronchitis pathogenesis
As a defense mechanism against chronic irritation of the tracheobronchial mucosa by cigarette smoke and/or other environmental pollutants, there is hypertrophy and hyperplasia of the submucosal mucous glands in the large airways with the resultant hypersecretion of mucus accounting for the increase sputum production
chronic bronchitis clinical data
patients tend to be cyanotic since a greater proportion of their reduced hemoglobin is not converted to oxyhemoglobin as it passes through the lungs
chronic bronchitis complications
Repeated infections, right-sided heart failure, peptic ulcers, and respiratory failure are the major complications
emphysema "pink puffers" characteristics
-an abnormal, permanent, destructive lesion of the pulmonary parenchyma which leads to an increase in the size and volume of the air spaces distal to the terminal bronchiole
-major pathophysiologic disruption is distal airway tissue destruction with resultant loss of elastic recoil rather than large airway obstruction as is seen with chronic bronchitis
a. Centrilobular emphysema characteristics
-characterized by destructive changes primarily to the respiratory bronchioles
-Most striking in the upper lobes, it is seen most frequently in cigarette smokers and for that reason is often also associated with chronic bronchitis
b. Panlobular emphysema characteristics
Most frequently seen in the lower lobes, this pattern is characterized by uniform involvement of the acinus and is seen in patients with inherited or acquired alpha-1-antitrypsin deficiency, especially if they also smoke.
emphysema clinical presentation
-usually present with a history of progressive dyspnea and often weight loss due to the increased work involved in respiration
-diameter of the chest is increased (barrel chest) due to the increased lung volume
-Expiration is prolonged due to the lack of elastic recoil, and patients tend to exhale through pursed lips since this helps generate a greater compressive force by the chest wall
C. BRONCHIAL ASTHMA characteristics
characterized by an increased sensitivity of the tracheobronchial tree to various stimuli and is manifested by acute, widespread, narrowing of the small airways due to bronchoconstriction (rapidly reversible with bronchodilators) and a more chronic narrowing of the airways due to inflammation, edema, and increased mucus production (which is more slowly responsive to treatment)
a. Atopic (allergic) bronchial asthma
This form is an IgE mediated hypersensitivity reaction (Type I) and can be triggered by a wide variety of environmental allergens. Onset typically occurs in childhood, and there is often a family history of allergy.
Non-atopic bronical asthma
form is frequently triggered by upper respiratory infections (primarily viral). The mechanism of action is unknown. IgE levels are usually normal, and a family history is usually lacking.
bronchial asthma complications
include status asthmaticus, respiratory failure, pneumothorax or pneumomediastinum, pneumonia, atelectasis, and mucoid impaction
BRONCHIECTASIS characteristics
-permanent dilatation of bronchi and bronchioles resulting from inflammatory damage to their walls. -may be due to bronchial obstruction, necrotizing pneumonia, or a variety of congenital or inherited conditions (notably cystic fibrosis)
-ultimately results in weakening, abnormal dilatation, and fibrosis
-usually associated with cough and copious production of purulent sputum.
CYSTIC FIBROSIS (mucoviscidosis) characteristics
an inherited autosomal (chromosome 7) recessive disorder of exocrine glands characterized by abnormally viscous secretions and, depending on the severity of the disease, clinically manifested by pancreatic insufficiency, chronic respiratory disease, electrolyte disturbances, infertility, and occasionally cirrhosis of the liver
III. RESTRICTIVE LUNG DISEASES characteristics
In contrast to obstructive diseases, this group of disorders is characterized by decreased total lung capacity. This may be due to loss of lung tissue (surgical resection, pulmonary infarction, atelectasis), filling of alveolar spaces (pneumonia, edema, hemorrhage), or infiltration and thickening of the pulmonary interstitium (interstitial edema, inflammation, or fibrosis).
ATELECTASIS characteristics
-refers to a condition in which there is either collapse of alveoli or incomplete filling of alveoli
-pathophysiologic effect is to cause a decrease total lung volume and a restrictive pattern of pulmonary function
-Primary atelectasis results from the failure of lungs to ventilate at time of birth
1. TYPE I Respiratory distress syndrome (HYALINE MEMBRANE DISEASE, RESPIRATORY DISTRESS OF THE NEWBORN)
Immature development of the lung results in a deficiency of surfactant, the lipid material synthesized by the alveolar cells (Type II pneumocytes) that is needed to lower the surface tension of the alveoli and help maintain their patency during expiration
1. TYPE I Respiratory distress syndrome (HYALINE MEMBRANE DISEASE, RESPIRATORY DISTRESS OF THE NEWBORN) pathogenesis
Decreased surfactant increases the surface tension of the alveoli allowing them to collapse during expiration. This then requires greater inspiratory effort to expand the atelectatic airways (clinically manifested as nasal flaring and retraction of the ribs and sternum during inspiration)
1. TYPE I Respiratory distress syndrome (HYALINE MEMBRANE DISEASE, RESPIRATORY DISTRESS OF THE NEWBORN) complications
To maintain airway patency and adequate oxygenation, ventilatory support with positive end expiratory pressure and high concentrations of O2 may be necessary. This can lead to pressure-induced tissue injury and O2 toxicity. Retrolental fibroplasia may result in subsequent blindness and bronchopulmonary dysplasia may lead to chronic (primarily restrictive) lung disease
2. TYPE II (ADULT RESPIRATORY DISTRESS SYNDROME, DIFFUSE ALVEOLAR DAMAGE, "SHOCK" LUNG) characteristics
-may involve a wide variety of triggering mechanisms (high altitude exposure, anaphylaxis, exposure to chemical or physical irritants, fulminating bacterial or viral infection, drugs, oxygen toxicity, etc.) all of which have the common denominator of widespread microvascular injury
PNEUMOCONIOSES characteristics
-primarily occupational diseases caused by the inhalation of inorganic mineral dusts (coal dust, silica, asbestos, talc, kaolin, beryllium, etc)
-These dusts will elicit, to a variable degree, inflammation and pulmonary fibrosis as a host response
-The size, shape, concentration, and solubility of the inhaled material has a bearing on the resultant damage produced.
D. CHRONIC INTERSTITIAL (NON-INFECTIOUS) PNEUMONIAS characteristics
encompass a group of diseases which have in common an alveolitis with subsequent fibrosis. The end result of each of these is "honeycomb" lung characterized by multiple cystic spaces separated by dense fibrous scars. The cystic spaces represent dilated bronchioles caused by contraction of the fibrous scars and are often filled with mucus and cellular debris.
E. SARCOIDOSIS characteristics
-systemic disease of unknown etiology
-The most widely accepted hypothesis is that it represents an abnormal immunologic response to a variety of non-specific agents or antigens
-presenting symptoms in thoracic sarcoidosis include cough, dyspnea, chest pain, loss of weight, malaise or excessive fatigue
A. PULMONARY EDEMA characteristics
-involves the accumulation of extravascular fluid within the lungs, initially in the interstitial space and subsequently spilling over into the alveoli
-due to either disturbances of the normal hemodynamic equilibrium (congestive heart failure, myocardial infarction, hypertensive heart disease, longstanding mitral stenosis, etc.) or microvascular injury
B. PULMONARY EMBOLUS characteristics
-relates to the impaction of a free floating mass (usually thrombus) in the pulmonary arterial bed
-pathologic change and the clinical manifestations of pulmonary emboli are dependent on the size of the vessels in which the embolus impacts and also on the preexistent cardiovascular status of the lung.
PULMONARY EMBOLUS clinical characteristics
-Small emboli lodge in peripheral pulmonary vessels causing local congestion, edema, and hemorrhage but may produce no clinical symptoms, but can accumulate
-Massive embolization, particularly of the saddle type, may induce the immediate catastrophic syndrome of acute heart failure and sudden death
pulmonary embolus diagnosis
When pulmonary emboli are clinically suspected, the best primary screening tool is a ventilation-perfusion scan of the lung (chest x-rays are frequently normal).
pulmonary embolus treatment
Most patients receive heparin anticoagulation. In some patients, thrombolytic therapy may be appropriate. Long term oral anticoagulation (3-6 months or longer) is also recommended
pulmonary embolus prevention
In clinical situations where venous thrombosis is likely (post-surgery, immobilization, etc), graduated compression stockings and intermittent pneumatic compression boots may be used
C. PULMONARY INFARCTION characteristics
-signifies ischemic coagulation necrosis of lung parenchyma and is almost always due to pulmonary emboli
-not, however, synonymous with pulmonary emboli. -occur in only 5-10% of pulmonary emboli
-generally occur in those patients in whom there is preexisting impairment of the bronchial artery circulation
pulmonary infarction clinical characteristics
-When symptomatic, a clinical triad indicative of pulmonary infarction includes dyspnea, hemoptysis, and pleuritic chest pain (with possible pleural friction rub)
-low grade fever and leukocytosis may be additional findings
-Radiologically, a wedge-shaped consolidation along a pleural surface is classic although not that frequently seen
-Elevation of the diaphragm may occur.
A. BACTERIAL PNEUMONIA characteristics
-Pneumonia can be caused by a wide variety of bacterial agents
-pathologic changes depends on the specific agent and the host response to that agent
-Streptococcus pneumoniae (pneumococcus) is most common agent
a. Lobar pneumonia characteristics
Lobar refers to an extensive inflammatory consolidation involving an entire lobe or large portion thereof. The lobar distribution tends to reflect the virulence of the organism and/or the decreased effectiveness of the patient's defense mechanisms
b. Bronchopneumonia characteristics
refers to a less extensive than lobar pneumonia, but possibly more destructive, inflammatory consolidation which occurs in patches throughout a lobe (most frequently lower lobes) or lung, typically following tracheobronchial injury by a bronchitis/bronchiolitis or as complications of systemic disorders such as malnutrition, alcoholism, or congestive heart failure with pulmonary edema
2. CLINICAL PRESENTATION of pneumonia
-clinical course is typified by a sudden onset, often with shaking chills, followed by high fever
-first, cough is dry or productive of watery sputum. -Later, the sputum becomes thick, purulent, and hemorrhagic ("rusty" sputum)
-associated pleuritis manifests itself by pleuritic pain and a friction rub, and there may be a pleural effusion
B. MYCOPLASMA/VIRAL PNEUMONIAS characteristics
-caused by Mycoplasma pneumoniae (primary atypical pneumonia) and a wide variety of viruses but are morphologically and clinically similar
-Clinically, there is often a history of recent upper respiratory tract infection, and there may be an irregular fever with myalgia and malaise
C. MYCOTIC PNEUMONIAS characteristics
In general, the fungi are weak antigens and can cause tissue damage primarily by virtue of the hypersensitivity reaction by the host against the fungal proteins. Most of the deep mycoses (histoplasmosis, coccidioidomycosis, North American blastomycosis, cryptococcosis, etc) induce a chronic granulomatous inflammatory reaction
pulmonary tuberculosis prevalence
Worldwide, tuberculosis kills more adults than any other infectious agent. Although the incidence in the U.S. declined dramatically after the introduction of effective anti-tuberculous drugs, the incidence has been steadily rising since 1985, primarily due to the increased numbers of immunosuppressed patients (AIDS, etc.) and the emergence of drug-resistant strains of the mycobacterium
1. PRIMARY TUBERCULOSIS route of infection
-most common route of infection is through inhalation of contaminated aerosol droplets from an infected individual
tuberculosis- Ghon focus definition
The primary focus of infection in the lung parenchyma is usually subpleural, most commonly in the upper portion of lower lobe or the lower portion of the upper lobe. This focus is called the Ghon focus and typically has central caseous necrosis.
tuberculosis- the primary Ghon complex definition
The combination of the subpleural lesion and the hilar node involvement
2. SECONDARY TUBERCULOSIS characteristics (adult, reactivation, postprimary TB)
-Due to the previous exposure and development of hypersensitivity, reexposure to the organism or reactivation of latent organisms produces a prompt granulomatous tissue response often with caseous necrosis
-Cavitation is considered the anatomic hallmark of secondary tuberculosis
secondary tuberculosis- Assmann focus definition
-Since mycobacterium organisms prefer areas of high oxygen tension, reactivation is almost invariably localized to the apices of one or both upper lobes
-Many men like big butts and cannot lie
E. CHEMICAL PNEUMONIA characteristics
Aspiration is the most frequent cause of chemical pneumonia and occurs most frequently in unconscious patients, those with repeated vomiting episodes, and those with depressed cough reflexes (alcoholic intoxication, central nervous system malfunction, acute drug intoxication, etc).
F. PULMONARY ABSCESS pathogenesis
Aspiration is also the most common cause of lung abscess with inoculation of the lower respiratory tract by anaerobic organisms from the oral cavity. These abscesses tend to be solitary and occur most frequently on the right side due to the shallow angle of the right mainstem bronchus
Pulmonary abscess pathology
Abscesses consist of localized suppuration and liquefaction necrosis of lung parenchyma, which in chronic cases (> 6 weeks duration) may elicit considerable fibroblastic proliferation in the wall. They may be solitary or multiple and may vary in diameter from a few millimeters to large cavities of 5-15 cm.
pulmonary abscess clinical symptoms
Generally, there is a fever with a prominent cough, often accompanied by copious amounts of foul smelling (esp. anaerobic organisms) or bloody sputum. Chest pain and weight loss may also be present. X-rays may show a homogenous density which, if there is communication with an airway, may reveal an air-fluid level.
A. BRONCHOGENIC CARCINOMA characteristics
-bronchogenic carcinoma is the leading cause of cancer deaths in the U.S.
-Smoking is probably the single most important etiologic factor and is most closely associated with squamous cell carcinomas and small cell carcinomas. The risk is proportional to the number of cigarettes smoked daily, the duration of the habit, and the tendency to inhale. -Environmental/occupational exposure (uranium, asbestos, chromates, nickel, coal, iron, arsenic, radiation, etc) also plays a role in some cancers.
BRONCHOGENIC CARCINOMA- Squamous cell carcinoma (35%) characteristics
primarily a central lesion and is the cancer most closely associated with smoking, evolving from preceding dysplastic squamous metaplasia of the bronchial epithelium
BRONCHOGENIC CARCINOMA- Adenocarcinoma (35%)
-majority of adenocarcinomas are peripheral lesions that tend to spread through submucosal lymphatics to the hilar lymph nodes
-remain clinically silent until signs and symptoms of definite metastases appear
BRONCHOGENIC CARCINOMA- Small cell undifferentiated (oat cell) carcinoma (20%) characteristics
-Almost always a central lesion, this type of cancer occurs predominantly in men, is associated with smoking, and progresses rapidly with wide dissemination
-Thought to arise from an endocrine type of cell, these tumors are notorious for producing hormone-like substances (ADH, ACTH, gonadotropins, etc) that cause paraneoplastic syndromes.
BRONCHOGENIC CARCINOMA- CLINICAL PRESENTATION
When symptomatic, the usual presentation consists of chronic cough (often with hemoptysis), chest pain, anorexia and weight loss, and dyspnea. X-ray almost always shows an abnormal mass.
Metastatic neoplasms vs. primary neoplasms prevalence in lungs
Metastatic neoplasms are far more common than primary neoplasms and tend to present as multiple nodules usually in the lung periphery.
D. EPENDYMA definition
These are specialized ciliated glial cells which line the ventricular cavities and central canal of the spinal cord
NONSPECIFIC CNS REACTION TO INJURY
General reactions to injury include cerebral edema (local or generalized) which in turn may increase intracranial pressure (CSF pressure > 200 mm H2O)
HYDROCEPHALUS characteristics
Obstruction of CSF flow, an increase in CSF production, or a decrease in reabsorption will result in hydrocephalus with ventricular distention. If hydrocephalus occurs before the cranial bones fuse in infancy, there is resultant enlargement of the head. After the cranial bones fuse, acute hydrocephalus will cause symptoms related to increased intracranial pressure (headache, nausea, vomiting, etc.)
SKULL FRACTURES characteristics
Depressed fractures of the calvarium may tear vessels and the dura and contuse or lacerate underlying brain tissue. Fractures of the base of skull may communicate with the sinuses or middle ear and result in leakage of CSF and increased risk of meningitis and intracranial infections
concussion characteristics
This is a clinical diagnosis characterized by transient loss of consciousness with retrograde and anterograde amnesia. There is only minor damage to the CNS, but repetitive concussions (football, boxing, etc) can lead to permanent damage.
contusion characteristics
usually superficial areas of necrosis of the cortex resulting from crushing of CNS tissue by blunt force (coup lesions). If the brain is set in motion, it will strike the inside of the skull opposite the point of original contact and may produce contusions (contrecoup lesions) that are more extensive that the coup lesions
epidural hematoma characteristics
refers to hemorrhage into the potential space between the skull and dura mater. Most frequently, epidural hematomas result from tearing of the middle meningeal artery and are located over the temporal and parietal areas. Clinical course is characterized by transient loss of consciousness with a subsequent lucid interval followed, within 24 hours, by coma and signs of increased intracranial pressure
subdural hematoma
refers to hemorrhage into the potential space between the dura mater and leptomeninges. It is usually associated with blunt trauma but without overlying skull fracture.
SUBARACHNOID HEMORRHAGE characteristics
This refers to bleeding into the space between the brain and the leptomeninges. Unlike epidural or subdural hematomas, in this instance blood can be identified in the cerebrospinal fluid. Trauma is the most common cause but other conditions can also lead to subarachnoid bleeding
HYPOXIC ENCEPHALOPATHY
produced by any process that reduces the effective oxygenation of the brain. Neurologic change depends on the extent and duration of the hypoxia and the length of survival after the insult. Acute hypoxia is more damaging than chronic hypoxia.
vascular thrombosis infarction characteristics
Infarcts due to thrombosis may be preceded by transient ischemic attacks (TIA) which are neurologic deficits (blindness, paralysis, etc) that may be of sudden onset but resolve within a short period of time.
CNS HEMORRHAGE (non-traumatic)
-common cause is preexisting systemic hypertension which, over time, weakens the small arteries in the deep white matter of the brain
-hemorrhage may rupture into the ventricular system, or brain herniation may occur secondary to the expanding volume of blood
SACCULAR ("BERRY") ANEURYSMS characteristics
Most occur in the middle cerebral artery and its branches and tend to arise at the bifurcation of vessels. Although most remain asymptomatic throughout a person=s life, spontaneous rupture and hemorrhage may lead to "stroke" or sudden death
VASCULAR MALFORMATION characteristics
This occurs in approximately 5% of the general population. Venous malformations (67%) are the most common but are usually asymptomatic. Arteriovenous malformations (12%) are less common but more likely to cause intracerebral hemorrhage by rupture.
ACUTE LEPTOMENINGITIS characteristics
-usually is a secondary infection due to extension of a local ear or sinus infection, penetrating wounds, or blood-borne organisms from a distant site
-meninges become congested, clouded and purulent exudate may be observed
-Neutrophils seen in the CSF
-Common symptoms include agitation, irritability, headache, photophobia, and stiff neck
-must be caught and treated early
INTRAPARENCHYMAL ABSCESS characteristics
Most abscesses have no definable source. Others will be related to sinus infection, ear infection, direct implantation, or hematogenous spread of bacteria. Septic emboli (from endocarditis or pulmonary infection) often cause multiple abscesses. Symptoms are usually related to associated edema, increased intracranial pressure, and local destruction
viral meningitis characteristics
-may be a complication of many systemic viral diseases but usually is not as clinically relevant as bacterial meningitis
-Lymphocytes can be observed in the CSF, and it usually runs a self-limited course.
ENTEROVIRUS characteristics
-most common cause of viral meningitis
-causative agent of poliomyelitis
-heralded by nonspecific upper respiratory tract infection, GI symptoms, and fever which may progress to headache and stiff neck
-Most cases resolve without sequelae, but if it progresses to involve the large motor neurons in the spinal cord and brainstem, the permanent lower motor neuron paralysis characteristic of polio may result
HERPES VIRUSES characteristics
-virus lives in the nervous system ganglia and periodically produce painful skin vesicles and ulcers along the nerve distribution of those ganglia. -Involvement of the CNS may be fatal
-Babies born by vaginal delivery to women with genital herpes are at risk for CNS infection as well as immunocompromised patients.
RUBELLA characteristics
Transplacental infection during the first trimester of pregnancy causes reduction in cell growth and cell division in the fetus. Many fetuses are stillborn or aborted, but those born alive may show cardiovascular and pulmonary defects, blindness, deafness, mental retardation, and low birth weight.
rabies characteristics
Primarily a disease of animals (cows, skunks, fox, etc), man may become infected by direct inoculation or less commonly inhalation. Incubation period is 1-3 months and the onset is characterized by fever, malaise, and headache which progresses to profound CNS sensitivity (pain, convulsions, photophobia), coma, and death.
tuberculosis meningitis characteristics
Tuberculous meningitis at one time was the most common cause of meningitis in children but is now uncommon and seen primarily in adults. It arises from hematogenous spread from a pulmonary focus. It always results in death if untreated; 30% mortality if treated.
neurosyphilis characteristics
-occurs in about 30% of untreated cases of syphilis
-Cerebral involvement produces psychotic dementias (general paresis of the insane) which begin about 15 years after the initial infection
-Tabes dorsalis (lack of coordination of voluntary movements and sensory disorders) results from involvement of the spinal cord and has an onset 10-25 years after the primary infection.
Cryptococcus characteristics
most common fungal infection of CNS, has insidious onset with headache or behavioral changes and will lead to death if untreated
Dementia definition
refers to impairment of orientation, memory, intellect, and judgement with associated alterations in mood and behavior. Dementias are often, but not always, associated with degenerative diseases and may also be seen in disorders due to other causes.
A. ALZHEIMER DISEASE characteristics
occurs in the later stages of life and has a slow insidious onset with behavioral changes (anxiety, depression, insomnia, visual hallucinations, paranoia), recent memory loss, and progressive intellectual impairment with eventual inability to comprehend, communicate, or care for oneself
B. HUNTINGTON DISEASE characteristics
-autosomal dominant inherited disease with the initial onset of involuntary muscle movements (choreiform movement) and facial grimaces occurring in mid-adult life
-followed by personality changes, emotional disturbances, and dementia ultimately leading to death within 10-15 years of diagnosis
-disease has been traced to a genetic defect on chromosome 4, and pathologically there is atrophy of specific areas within the deep white matter of the cerebral hemispheres.
C. PARKINSON DISEASE (paralysis agitans) characteristics
-relatively common disease heralded by resting "pill-rolling" tremors and slow movements (bradykinesia) which progresses to rigidity and postural changes, poor balance, shuffling gate, and a "blank" facial expression
-degeneration and depigmentation of the substantia nigra region of the brain stem indicating loss of neurons which release the neurotransmitter dopamine
D. AMYOTROPHIC LATERAL SCLEROSIS (ALS) characteristics
-degenerative disease of older adults characterized by gradual progressive motor weakness leading to total paralysis and respiratory failure within 3-5 years
-Sensory function and mental function remain intact
A. MULTIPLE SCLEROSIS characteristics
-represents an autoimmune reaction against the oligodendroglia that may be triggered by a viral infection with prolonged latent period
-highly variable clinical symptoms which may include paresthesias, visual disturbances, muscle weakness, incoordination, and speech difficulties
B. ACUTE IDIOPATHIC POLYNEURITIS (Guillain-Barré)
-post-infectious autoimmune disorder where there is bilateral progressive ascending motor paralysis affecting both spinal and cranial nerves often preceded by "viral" respiratory or gastrointestinal disease
-The usual outcome is gradual recovery without residual defect, but it may become chronically progressive
IX. METABOLIC STORAGE DISEASES characteristics
-Diseases such as Tay-Sachs and Niemann-Pick are relatively rare but devastating diseases of genetic origin that result in various enzyme deficiencies which interrupt normal metabolic pathways and cause accumulation of precursor substances in the neural tissues and systemic organs
-Clinical manifestations vary but may involve severe retardation or early death
X. NEOPLASTIC DISEASE characteristics
-no specific signs or symptoms of neoplastic disease of the CNS
-Clinical manifestations depend on local effects (irritative, compressive, or destructive effects on the particular sites involved) and generalized effects (increased intracranial pressure, edema, hemorrhage, etc.)
-All primary CNS neoplasms (arising in the neural parenchyma) are potentially biologically malignant but extraneural metastases are rare
A. MENINGIOMA characteristics
-generally a slow growing, extraneural, benign neoplasm which occurs most frequently in middle-aged adults and may or may not be symptomatic
-prognosis is excellent provided that the tumor is accessible to surgical removal
B. ASTROCYTOMAS definition
-most common glial tumors arising in the brain
-There are four different grades of astrocytoma depending on the cellular differentiation.
WELL DIFFERENTIATED ASTROCYTOMA (GRADE I) characteristics
-arises in the subcortical white matter with a peak incidence in the 3rd and 4th decades
-Symptomatology may include seizures, increased intracranial pressure, motor deficits, and mental changes.
GLIOBLASTOMA MULTIFORME (GRADE IV) characteristics
-Unfortunately, this highly malignant neoplasm is the most common primary brain tumor in adults
-usually arise in the frontal or temporal lobes and enlarge rapidly
-Symptomatology is the same as other astrocytomas but with more rapid progression and deterioration. -Untreated, the average survival is 14 weeks
DUCHENNE TYPE characteristics
-sex-linked recessive disease (expressed in males only) which usually does not become apparent until after one year of age
-affects primarily the pelvic girdle muscles causing difficulty walking and disturbances of gait
-gastrocnemius muscles may appear enlarged due to pseudohypertrophy (fatty infiltration between muscle fibers)
FACIOSCAPULOHUMERAL TYPE characteristics
-autosomal dominant disease which characteristically first appears in adolescence
-initially affects the muscles of the face and shoulder girdle and over a long period of time affects the trunk and legs
-no significant decrease in life expectancy
MYOTONIC DYSTROPHY characteristics
-autosomal dominant disease which appears early in adult life and tends to affect facial muscles and the distal muscles of the extremities
-characterized by an inability to relax muscles after contraction
-Common associated signs are cataracts, frontal baldness, ptosis of eyelids, cardiac abnormalities and testicular atrophy
MYASTHENIA GRAVIS characteristics
-an autoimmune disease that usually becomes evident in early adulthood and is characterized by abnormal muscular fatigue and weakness which is initially manifested in the most active muscles (extraocular, face, tongue, upper extremities) and may progress to involve the respiratory muscles
-destruction of the acetylcholine receptors of the muscle fiber at the NMJ
endocrine effects definition
When secreted into the circulation, hormones can exert their effects on distant sites
paracrine effects definition
when diffused through interstitial tissue, they can exert their effects on adjacent sites
autocrine effects definition
may also exert their effects on their own cell of origin
anterior PITUITARY gland normal characteristics
-anterior pituitary produces growth hormone (GH), adrenal corticotropic hormone (ACTH), follicle stimulating hormone (FSH), luteinizing hormone (LH), thyroid stimulating hormone (TSH), and prolactin (PL)
-release of pituitary hormones are controlled by releasing factors that are produced in the hypothalamus of the brain
posterior pituitary gland normal characteristics
-posterior pituitary hormones, antidiuretic hormone (ADH, vasopressin) and oxytocin, are actually formed in the hypothalamus and transported to the posterior lobe via the pituitary stalk where they are stored prior to release
HYPERPITUITARISM characteristics
autonomous pituitary hypersecretion is the most common basis of hyperpituitarism and is usually due to a functional, benign, monoclonal neoplasm (pituitary adenoma) which secretes one of the polypeptide hormones (PRL, GH, ACTH).
PROLACTIN EXCESS characteristics
-most common secretory product of pituitary adenomas
-In womern this often results in anovulation, 20 amenorrhea, and galactorrhea
-In men, it may produce infertility or impotence, but it may also be relatively asymptomatic and not be discovered until the tumor grows to a size that produces symptoms due to its mass effect.
gigantism definition
-Before puberty, an increase in growth hormone is reflected by exaggerated skeletal growth
-often accompanied by nerve, muscle, and joint problems
acromegaly (2nd most common functional disorder of the pituitary) definition
-After puberty, hypersecretion of GH causes acromegaly
-involves insidious enlargement and coarsening of the face, hands, and feet.
ACTH EXCESS results in
Increased ACTH secretion results in Cushing disease
HYPOPITUITARISM cause
Although hypothalamic problems can give rise to isolated anterior lobe hormone deficits (GH deficiency is the more common), hypopituitarism most commonly results from extensive destruction of anterior lobe tissue ( > 75% destruction before symptoms begin to appear) and leads to panhypopituitarism (Simmond disease).
hypopituitarism CLINICAL FEATURES
Temporally, symptoms are sequentially related to deficiencies of growth hormone, gonadotropins (FSH and LH), TSH, and ACTH.
1. GROWTH HORMONE DEFICIENCY characteristics
Before puberty, this can cause pituitary dwarfism (short stature but with normal proportions) and delayed sexual maturity. After puberty, it is generally asymptomatic.
2. GONADOTROPIN DEFICIENCY characteristics
In children, this may cause delayed puberty. In adult females there may be amenorrhea, loss of secondary sex characteristics, and atrophy of the ovaries and external genitalia; while in adult males there may be aspermia, loss of secondary sex characteristics, and testicular atrophy.
TSH deficiency produces
This produces symptoms of hypothyroidism
ACTH DEFICIENCY produces
This produces symptoms of hypoadrenalism
most frequent cause of hypopituitarism
NON-FUNCTIONING ADENOMA which compresses pituitary gland
SHEEHAN SYNDROME characteristics
-results from an infarct of the anterior lobe of pituitary gland secondary to hypotension or shock
-classically, it is due to obstetric hemorrhage and hypotension (postpartum pituitary necrosis
OXYTOCIN- excess or deficiency causes
Apparently, neither excessive nor deficient production of oxytocin has recognizable associated clinical effects
ADH fxns
-released in response to increases in osmolality of body water or a decrease in blood volume
-Together with thirst, which promotes water ingestion, ADH regulates water balance to maintain steady-state solute concentrations within tissues
ADH EXCESS SECRETION causes
-The syndrome of inappropriate ADH (SIADH) results in renal retention of water with hypervolemia, hemodilution, and an inability to dilute urine
-usual cause is ectopic production of ADH by various neoplasms (classically oat cell carcinoma of the lung).
ADH deficient secretion causes
Diabetes insipidus results in clinical symptoms similar to diabetes mellitus (polyuria, polydipsia, etc.) and is generally due to posterior pituitary tissue destruction (metastatic neoplasm, iatrogenic), disruption of hypothalamic-pituitary connections (trauma, inflammation), or idiopathic causes
nephrogenic diabetes insipidus definition
there may be sufficient ADH secretion but an end-organ unresponsiveness to the hormone
MASS EFFECTS of pituitary
Due to its location at the base of the brain, expanding pituitary masses (primary or metastatic neoplasm, edema, infiltration of stroma, etc) can produce visual impairment (usually bitemporal hemianopsia) when there is impingement on the optic chiasm or compression of the oculomotor nerves
THYROID normal characteristics
-composed of follicles of varying size set in a fibrovascular stroma which contains parafollicular or "C" cells that secrete the hormone calcitonin. -Calcitonin opposes the effects of parathyroid hormone
-major thyroid hormones are T3 and T4 which are released in response to stimulation by TSH from the pituitary
HYPERTHYROIDISM (thyrotoxicosis) characteristics
hypermetabolic state produced by increased T4 and/or T3. The disorder is clinically manifested by nervousness and hyperkinesia, sweating, heat intolerance, tachycardia, cardiac arrhythmias, weight loss despite an increased appetite, fatigue and muscle weakness, tremors, warm moist skin and fine oily hair, emotional labiality, and hyperdefecation
HYPOTHYROIDISM common causes
deficiency of thyroid hormones and may result from intrinsic thyroid disease (primary hypothyroidism) or from a deficiency of TSH (secondary hypothyroidism) as a consequence of pituitary or hypothalamic disease
LATE CHILDHOOD OR ADULT HYPOTHYROIDISM (myxedema) characteristics
-hypometabolic state manifested by insidious onset of tiredness, apathy, and lethargy
-Mental faculties become dulled and speech becomes slowed
-skin becomes rough and the hair becomes coarse and dry
-eriorbital soft tissue becomes puffy, the tongue becomes enlarged, and the heart becomes flabby and dilated
-Major causes include surgical, chemical, or radiation ablation; primary idiopathic myxedema; and Hashimoto thyroiditis
GESTATIONAL OR EARLY INFANCY HYPOTHYROIDISM (cretinism) characteristics
-can arise from nutritional lack of iodine or from defects in thyroid hormone synthesis. A deficiency early in fetal life will retard brain development causing severe mental retardation, spasticity, and deaf-mutism (neurologic cretinism)
-If untreated, there is impaired skeletal growth, dry skin, and protuberant abdomen. Later manifestations include wide set eyes, broad flat nose, enlarged tongue, and periorbital puffiness
mass effects thyroid gland
Goitrous enlargement and encroachment on adjacent structures may produce dysphagia, inspiratory stridor, hoarseness, dyspnea, etc.
HASHIMOTO THYROIDITIS characteristics
-characteristically presents in middle aged women as a gradual thyroid enlargement, usually painless, associated with insidious onset of hypothyroidism. -autoimmune in origin and has an increased incidence in patients with other autoimmune disorders.
GRAVES DISEASE (DIFFUSE TOXIC GOITER) characteristics
produces a symptom complex seen predominantly in young, adult women which is characterized by hyperthyroidism, moderate thyroid enlargement, ocular changes (proptosis, muscle weakness, diplopia, periorbital edema, lid lag), and localized thickening of the skin over dorsum of the feet and legs (pretibial "myxedema")
GOITERS definition
This simply refers to an enlargement of the thyroid gland
DIFFUSE NONTOXIC GOITER (simple goiter, colloid goiter) characteristics
-gradual painless enlargement of the thyroid due to compensatory hyperplasia secondary to a defect in production or an inability to secret functional thyroid hormone
-can be due to hereditary defects in hormone synthesis or hormone transport, deficient iodine intake, or environmental goitrogens
MULTINODULAR GOITER (adenomatous goiter) characteristics
end result of a long-standing diffuse nontoxic goiter and can cause tremendous thyromegaly (up to 1500 gm). Since they are derived from simple goiters, they are more frequently seen in females but in an older age population
BENIGN NEOPLASMS of thyroid characteristics
-vast majority of benign neoplasms are adenomas which arise from follicular epithelial cells
-can either enlarge slowly and painlessly over time, enlarge suddenly and painfully due to hemorrhage, or remain relatively static and asymptomatic. -Adenomas are felt to have little, if any, malignant potential
MALIGNANT NEOPLASMS of thyroid characteristics
-thyroid carcinomas are relatively infrequent overall. -Previous radiation exposure (especially in young females) increases the risk of malignancy but other forms of thyroid disease (goiter, adenoma, Hashimoto thyroiditis, Graves’s disease, etc.) do not appear to increase the risk.
PAPILLARY ADENOCARCINOMA of thyroid characteristics
-most common thyroid malignancy
-spread via lymphatics to regional lymph nodes and up to 20% of patients have cervical lymph node metastases at presentation
-may also be hematogenous spread to the lungs and bone. Nevertheless, the overall prognosis is excellent
FOLLICULAR CARCINOMA of thyroid characteristics
-tend to present in middle-aged females as a firm, irregular, nodular mass which also grows relatively slowly
-may appear grossly benign and encapsulated or aggressive and infiltrative
-tends to invade vessels and spread hematogenously to distant organs (lung, bone, liver, etc).
parathyroid REVIEW OF NORMAL
-four small glands which lie on or near the thyroid gland and function to regulate calcium metabolism. -Low serum levels of calcium causes the release of parathormone (PTH) which acts to increase absorption of calcium from the GI tract (by activating Vitamin D in the kidney), increase reabsorption of calcium from the urine, and increase reabsorption of calcium from bone stores
HYPERPARATHYROIDISM characteristics
-elevated PTH levels even in the face of hypercalcemia and increased urine calcium excretion
-if not recognized and treated, this will lead to the "stones" (renal stones); "bones" (bone demineralization /osteomalacia); "moans" (psychiatric disturbances, neurologic abnormalities, and muscle weakness); and "groans" (peptic ulcers, pancreatitis, and abdominal pains) associated with the advanced disease
HYPOPARATHYROIDISM characteristics
-generally characterized by low PTH and hypocalcemia. Hypoparathyroidism is most often the result of inadvertent removal of the parathyroids during thyroidectomy or radical neck dissection for cancer
-. Clinical symptoms include weakness, paresthesias, muscle cramps or tetany, cataracts, headache, and abdominal pain.
mass effects of parathyroid gland
Even the largest of parathyroid adenomas rarely cause clinical symptomatology
ADRENAL CORTEX produces
-outer zone of the cortex produces mineralocorticoids (aldosterone)
-inner zone produces glucocorticoids (cortisol)
-This area also secretes androgenic steroids (testosterone)
aldosterone characteristics
-acts to regulate extracellular fluid volume and potassium metabolism
-Effects on the kidney result in retention of sodium and water (possibly contributing to hypertension), and secretion of potassium
-primary stimulus for aldosterone secretion is serum sodium and potassium levels
cortisol fxns
increase appetite and promote fat deposition in the face, neck, and trunk; increase protein breakdown; and impair the inflammatory and immunologic responses
Cortisol and androgens are secreted in response to ( )
pituitary ACTH
EXCESS MINERALOCORTICOIDS characteristics
-Primary hyperaldosteronism (Conn syndrome) is most frequently seen in middle aged females and presents as moderate hypertension (due to the hypernatremia) which may be associated with chronic fatigue and weakness (rarely paralysis) and cardiac arrhythmias due to hypokalemia
-most common cause is an aldosterone-secreting cortical adenoma
EXCESS GLUCOCORTICOIDS (CUSHING SYNDROME) characteristics
relatively uncommon syndrome typically presents in middle age females and, in its fully developed form, is characterized by moon facies, buffalo hump, truncal obesity, purple abdominal stria, hirsutism, menstrual disorders, emotional liability, easy bruisability, susceptibility to infection, impaired glucose tolerance, muscle weakness, osteoporosis, etc. Primary hypercortisolism is associated with a low serum ACTH
Secondary hypercortisolism characteristics
-associated with high serum ACTH and is due to an ACTH-producing pituitary adenoma (Cushing disease). -may also result from ectopic production of ACTH. This generally leads to bilateral diffuse or nodular adrenal cortical hyperplasia
EXCESS ANDROGENS (ADRENOGENITAL SYNDROMES) characteristics
-may be inherited (autosomal recessive) disorders that affect the activity of various enzymes in the steroidogenesis pathway resulting in congenital adrenal hyperplasia
-metabolic defects all block the production of cortisol thereby eliminating the negative feedback on the pituitary, increasing the serum ACTH, and leading to bilateral diffuse or nodular hyperplasia
-Androgen secreting cortical tumors may also occur.
PRIMARY CHRONIC ADRENOCORTICAL INSUFFICIENCY (Addison Disease) characteristics
-results from any chronic destructive process that destroys more than 90% of the cortex
-Idiopathic atrophy (an autoimmune disorder) and miscellaneous destructive processes (tumor, infection, trauma, hemorrhage) account for most of the cases
-Clinically, slow onset of weakness and fatigue, anorexia, weight loss, nausea and vomiting, diarrhea/constipation, hypotension, and hyperpigmentation of skin.
SECONDARY ADRENOCORTICAL INSUFFICIENCY characteristics
-result of decreased ACTH secretion from the pituitary from whatever cause
-Since ACTH levels are low, these patients lack the cutaneous hyperpigmentation, and the other clinical features are usually less striking than those in Addison disease
ACUTE ADRENAL INSUFFICIENCY characteristics
-life threatening situation and may be the result of sudden stress in patients with Addison disease (Addisonian crisis) or the abrupt withdrawal of exogenous steroids
-may develop hypotension, shock, and vascular collapse.
ALPHA CELLS (20%) fxn
secrete glucagon which inhibits utilization of glucose by body tissues
BETA CELLS (70%) fxn
secrete insulin which promotes utilization of glucose by body tissues
DELTA CELLS (5%) fxn
secrete somatostatin which inhibits insulin and glucagon release
DIABETES MELLITUS characteristics
-most common endocrine disease and affects as much as 2% of the general population in the United States. -disorder results from a deficiency in production of insulin and/or end organ unresponsiveness to insulin
-hyperglycemia is the primary stimulus for the synthesis and release of insulin
-Over time, hyperglycemia (a common feature of diabetes mellitus) can lead to irreversible structural or functional alterations of various tissues
TYPE I (JUVENILE ONSET, INSULIN DEPENDENT) diabetes characteristics
-seen in 15% of diabetics and is the result of inadequate production of insulin
-mass and number of β cells in the pancreatic islets are reduced
-In chronic states there is severe atrophy of islets and virtual absence of β cells
TYPE II (ADULT ONSET, NON-INSULIN DEPENDENT) diabetes characteriestics
-In these patients, although there may be a deficiency or delay in insulin secretion from the beta cells, there is also an end-organ resistance to the effect of insulin
-This type of diabetes has a strong genetic component, but it is not well understood
-Often, these patients are obese (which hampers insulin action even in non-diabetics) but do not need insulin injections
INSULINOMA (ß cell tumors) characteristics
-most common islet cell tumors and 10% are malignant
-When they produce symptoms, they are related to hypoglycemic episodes that are temporally related to periods of high glucose utilization (fasting, exercise), cause stupor and loss of consciousness, and can be aborted by administration of glucose
GASTRINOMA characteristics
-associated with gastric acid hypersecretion and resultant intractable peptic ulceration of duodenum, stomach, and jejunum (Zollinger-Ellison syndrome). -develop fluid and electrolyte disturbance secondary to diarrhea and malabsorption
-Slightly over 50% of the gastrinomas are malignant.