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136 Cards in this Set
- Front
- Back
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Upper Respiratory air passages
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consist of the nasal cavities, paranasal sinuses, nasopharynx, oropharynx, hypopharynx, epiglottis, and larynx. Warm inspired air and filter large particles.
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Lower respiratory air passages
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consist of the trachea and its bronchial branches.
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level of brochi going down
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main stem bronchi, lobar bronchi, segmental bronchi, subsegmental bronchi, bronchioles, terminal bronchioles, respiratory bronchioles, alveolar ducts, and alveolar sacs.
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pores of Kohn
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provide communication between adjacent alveolar spaces.
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acinus
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represents the functional gas exchange area of the lung and is composed of a respiratory bronchiole and its branching structures.
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lobule
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smallest discrete portion of lung bounded by fibrous septa and consists of a terminal bronchiole and its branching structures. May contain 25-30 acini.
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large particles
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filtered by nasal hairs or trapped in the oropharynx.
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smaller particles
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trapped in the bronchial mucous blanket or the bronchiolar watery secretions rich in lysozyme and secretory IgA.
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smallest particles
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(1-5micros) are accessible to the terminal airways and alveoli where they are phagocytized by the alveolar macrophages.
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ventilation
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refers to the movement and distribution of air within the tracheobronchial system.
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diffusion
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the movement of O2 and CO2 between the alveolar space and the capillary blood
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perfusion
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refers to the flow and distribution of blood within the pulmonary vascular bed.
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obstructive pulmonary diseases
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result from the narrowing or obstruction of the tracheobronchial tree or from destruction of the pulmonary parenchyma.
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chronic bronchitis
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"blue bloaters." excessive mucous secretion within the bronchial tree. Chronic cough with sputum production for at least 3 months in two consecutive years.
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pathogenesis of chronic bronchitis
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hypertrophy and hyperplasia of the submucosal mucous glands in the large airways with the resultant hypersecretion of mucus accounting for the increase sputum production. Squamous metaplasia and dysplasia of the surface epithelium may also be present. Goblet cell metaplasia of small bronchi and bronchioles also contributes to the excessive mucus production, decreases the number of normal ciliated cells, hampering the normal clearance mechanism of mucous blanket. Air is usually able to be drawn into alveoli on inspiration. On expiration, air is trapped in the distal airways. Also fertile ground for bacterial growth.
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complications of chronic bronchitis
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repeated infections, right-sided heart failure, peptic ulcers, and respiratory failure.
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emphysema
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"pink puffers." 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. The major disruption is distal airway tissue destruction with resultant loss of ecstatic recoil rather than large airway obstruction as is seen with chronic bronchitis.
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centrilobular emphysema
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characterized by destructive changed primarily to the respiratory bronchioles. Most striking in the upper lobes, seen most frequently in smokers. Stimulates a destructive imflammatory response which inactivates antiproteases such as alpha 1-antitrypsin.
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panlobular emohysema
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Most frequently seen in lower lobes. 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.
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bronchial asthma
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characterized by an increased sensitivity of the tracheobronchial tree to various stimuli and is manifested by actue, widespread, narrowing of the small airways due to bronchoconstriction (rapidly reversible with bronchodilators) and a more chronic narrowing of the small bronchi and bronchioles due to inflammation, edema, and increased mucus production.
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Bronchial atopic (allergic) asthma
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this form is an IgE mediated hypersensitivity reaction and can be triggered by a wide variety of environmental allergens. Onset typically occurs in early childhood. Causes bronchostriction.
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Bronchial non-atopic asthma
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This form is frequently triggered by upper respiratory infections (primarily viral). The mechanism of action is unknown. IgE levels are usually normal.
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Bronchial miscellaneous asthma
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other causes of asthma include various drugs, occupational inhalants, exercise, and emotional stress.
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complications of bronchial asthma
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status asthmaticus, respiratory failure, pneumothorax or pneumomediastinum, pneumonia, atelectasis and mucoid impaction
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Bronchiectasis
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Permanent dilation of bronchi and bronchioles resulting from inflammatory damage to their walls.
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cystic fibrosis (mucoviscidosis)
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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.
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restrictive lung diseases
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characterized by decreased total lung capacity.
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Atelectasis
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Either collapse of alveoli or incomplete filling of alveoli which cause a decrease total lung volume and a restrictive patern of pulmonary function.
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Type 1 (Hyaline membrane disease, respiratory distress of the newborn) Etiology
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Immature development of the lung results in a deficiency of surfactant, the lipid material synthesized by the alveolar cells that is needed to lower the surface tension of the alveoli and help prevent their complete collapse during expiration.
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Type 1 (Hyaline membrane disease, respiratory distress of the newborn) Pathogenesis
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Decreased surfactant increases the surface tension of the alveoli allowing them to collapse during expiration. Then this requires greater inspiratory effort to expand the atelectatic airways.
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Type 1 (hyaline membrane disease, respiratory distress of the newborn) Complications
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Retrolenta fibroplasia may result in subsequent blindness and brochopulmonary dysplasia may lead to chronic lung disease.
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Type 2 (Adult respiratory distress syndrome, diffuse alveolar damage, "shock" lung)
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May involve a wide variety of triggering mechanisms all of which have the common denominator of widespread microvascular injury. Characterized by the acute onset of dyspnea and tachypnea with resulting tachycardia, hypoxemia that does not respond to therapy, and cyanosis.
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Pneumoconioses
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primarily occupational diseases caused by the inhalation of inorganic mineral dusts. These dusts will elicit inflammation and pulmonary fibrosis as a host response.
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Chronic interstitial (non-infectious) pneumonias
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A group of diseases which have in common an alveolitis with subsequent fibrosis. These patients have difficulty ventilating their lungs because of increased "stiffness" of the pulmonary parenchyma due to the fibrosis. End result is "honeycomb" lung.
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Sarcoidosis
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abnormal immunologic response to a variety of non-specific agents or antigens. The lung is the most frequently affected organ, which may include hilar lymphadenopathy (enlargment of lymph nodes).
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Bacterial pneumonia- lobar pneumonia
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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 patients defense mechanisms.
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bacterial pneumonia- brochopneumonia
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a less extensive, but possible more destructive, inflammatory consildation which occurs in patches throughout a lobe or lung, typically following tracheobronchial injury by a viral bronchitis/brochiolitis or as complications of systemic disorders. The bacteria colonize the airways and elicit an inflammatory response which extends out into surrounding lung parenchyma with tissue destruction, microabcess formation and subsequent scarring.
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bacterial pneumonia- clinical presentation
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Shaking chills followed by a high fever. A dry cough with watery sputum, followed by thick or "rusty" sputum. Complications include abcesses, empyema and sepsis.
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mycoplasma/ viral pneumonias
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Caused by mycoplasma pneumoniae and a wide variety of viruses. Pathologic lesions, widened alveolar walls. A persistent racking cough might be present.
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mycotic pneumonias
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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 induce a chronic granulomatous inflammatory reaction. They like to invade and obstruct vessels which can result in hemorrhagic infarcts.
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primary tuberculosis
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Primary focus of infection in the lung parenchyma is usually subpleural, most commonly in the upper portion of lower love or the lower portion of the upper lobe. Called the "Ghon focus" and may have caseous necrosis. The organisms may spread through lymph nodes. the combo of the subpleural lesion and hilar node involvement is called "primary Ghon complex".
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Secondary tuberculosis
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Reexposure to the organism produces a prompt granulomatous tissue response often with caseous necrosis. Almost always localized to the apices of the upper lobes.
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Cavitation
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The anatomic hallmark of secondary tuberculosis.
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chemical pneumonia
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Most frequently caused by chemical pneumonia and occurs most frequently in unconscious patients, those with repeated vomiting, and those with depressed cough reflexes. The lung parenchyma may be almost completely destroyed. Onset of cyanosis, dyspnea, tachypnea, tachycardia and shock, bloody frothy sputum, marked pulmonary congestion, and edema. Symptoms: recurrent cough and sputum production, fibrosis.
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pulmonary abcess- pathogenesis
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Aspiration is the most common cause. Abcesses tend to be solitary and occur on the right side. Other causes: bacterial pneumonia, bronchial obstruction, septic emboli, cysts of bullae and penetrating chest wounds.
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pulmonary abcess- pathology
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Abcesses consist of localized suppuration and liquefaction necrosis of lung parenchyma, which could elicit considerable fibroblastic proliferation in the wall. May be solitary or multiple.
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pulmonary abcess- clinical symptoms
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fever with a prominent cough, copious amounts of foul smelling or bloody sputum. Chest pain and weight loss.
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Bronchogenic carcinoma
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The leading cause of cancer deaths in the US. Smoking is the biggest factor. Arise from basal cells of the bronchial epithelium and differentiate into a variety of recognizable patterns.
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squamous cell carcinoma
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Primarily a central lesion and is the cancer most closely associated with smoking, evolving from preceding dysplastic squamous metaplasia of the bronchial epithelium. Tend to infiltrate locally before metastasizing.
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adenocarcinoma
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Peripheral lesions that tend to spread through submucosal lymphatics to the hilar lymph nodes.
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brochioloalveolar carcinoma
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A rare variant of adenocarcinoma that arises from bronchiolar epithelium.
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Small cell undifferentiated (oat cell) carcinoma
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Almost always a central lesion, occurs predominantly in men and is associated with smoking. Tumors are made up of small cells with little cytoplasm and are notorious for producing hormone-like substances that cause paraneoplastic syndromes.
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Bronchogenic carcinoma- clinical presentation
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When symptomatic, presentation consist of chronic cough, chest pain, anorexia and weight loss, and dyspnea. X-ray almost always shows an abnormal mass.
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Metastatic tumors
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Far more common than primary neoplasms and tend to present as multiple nodules usually in the lung periphery.
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Acute cystitis
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Predisposing factors include residual urine, stasis of urine, and mucosal urine. Initial infections almost always caused by E. coli. May find neutrophils and RBCs in the urine. Manifests by incresed frequency of urination, dysuria, and lower abdominal pain.
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residual urine
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incomplete emptying of the bladder.
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stasis of urine
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low urine output, urinary retention
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chronic interstitial cystitis (Hunner ulcer)
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A cystitis of unknown etiology presenting with suprapubic pain, frequency, urgency, dysuria, dyspareunia, and malaise. Pronounced chronic inflammation and fibrosis of the muscular wall of the bladder may be present. Most common in middle aged women.
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Calculi (stones)
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promoted by bacteria that make the urine alkaline. These generally result from precipitation of urinary salts and minerals, especially phosphates in assoc with magnesium and calcium. They irritate the bladder lining and predispose the recurrent infections.
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urinary tract neoplasms
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They tend to be multiple, both geographically and temporarily. Generally asymptomatic except for the presence of RBCs in the urine. Arise from transitional cell epithelium in a sequence of hyperplasia > dysplasia > carcinoma-in-situ > invasive carcinoma.
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painless hematuria
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presence of RBCs in the urine.
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Renal agenesis
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bilateral agenesis is incompatible with life and is associated with pulmonary hypoplasia and oligohydramnios. Unilateral agenesis is more common and seen most frequently in males. The remaining kidney may become hypertrophied and there may be association with esophageal atresia or congenital heart disease.
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cystic disease- simple cysts
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Common lesions arising from the cortex of the kidney and are of variable size. May be congenital or acquired and have no clinical significance except that, if large enough, they may be confused with a neoplastic mass.
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Renal calculi
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May arise when there is an excessive amount of stone constituents present in the serum or the urine and a favorable environment for the precipitation of those constituents exists. The majority of stones contain calcium. Large stones may remain in the pelvis of the kidney and are asymptomatic but predispose to infection and hematuria. Smaller stones are more likely to enter and obstruct the ureter and create clinical symptoms of extreme colicky abdominal pain radiating from the flank to the groin.
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adult polycystic kidney
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An autosomal dominant inheritance pattern. Almost always bilateral.May present with hematuria resulting from hemorrhage into the cysts, but will eventually develop chronic renal failure. Could be associated associated with benign hepatic cysts or saccular "berry" aneurysms of the cerebral vasculature.
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Urinary obstruction
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Result of ureteral or urethral compression/obstruction and may be due to stones, prostatic hypertrophy, congenital defects, tumors, pregnancy, etc. Obstruction predisposes to infection and stone formation.
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Hydronephrosis
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refers to the dilatation of the renal pelvis and calyces due to the obstruction to the outflow of urine and is associated with progressive atrophy of the kidney leading to functional failure. Changes become irreversible after about 3 weeks of complete obstruction or several months of partial obstruction.
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glomerular disease
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injury to the glomerulus is often reflected by the presence of blood (hematuria) or protein (proteinuria) in the urine implying that the filter which normally excludes these substances from the urine is damaged.
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Nephritic syndrome
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Characterized by hematuria, red blood cell casts, azotemia, hypertension, and oliguria. Immunologically mediated.
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Acute proliferative (post-infectious) glomerulonephritis
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Most commonly seen in children 1-3 weeks after a Group A beta-hemolytic streptococcal infection (strep throat) and is due to antigen-antibody complexes (type III immune hypersensitivity rxn) getting trapped in glomeruli. Damage basement membranes and allow RBCs to escape into the urine collecting system. In children there is malaise, fever, oliguria, hematuria, nausea, periorbital edema, and mild-moderate hypertension.
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Rapidly progressive glomerulonephritis (RPGN)
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A clinicopathologic syndrome in which there is a rapid progression into renal failure (within weeks of onset symptoms). May have an abrupt onset of oliguria and hematuria with lesser degrees of hypertension, edema, and proteinuria.
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Nephrotic syndrome
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A constellation of signs characterized by proteinuria, hypoalbuminemia, hyperlipidemia, lipiduria, and edema. Complications include infections and thrombosis.
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Major diseases causing nephrotic syndrome are
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Minimal change disease and membranous glomerulonephropathy
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MInimal change disease (lipid nephrosis, nil disease)
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Most common in children. there is very little morphologic change to the glomeruli.
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Membranous glomerulonephropathy
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Most common in adults. Characterized by thickening of the glomerular capillary basement membranes. Over a variable time span, most patients develop increasing blood urea nitrogen (BUN), hypertension, and progressive renal failure.
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pyelonephritis (tubulointerstitial nephritis)
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Most commonly infectious in origin, the dominant organisms are gram negative bacteria (usually E. coli) from the patient's intestinal tract. The normal kidney is resistant to blood borne infection therefore the most common route of infection is bacterial ascension from the urinary bladder.
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acute pyelonephritis
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Often associated with urinary obstruction, instrumentation of the urinary tract, vesicoureteral reflux, pregnancy, prior renal disease, and diabetes. Symptoms include acute onset of fever and malaise, costovertebral angle pain, dysuria, frequency, and urgency. Complications include necrotizing papillitis, pyonephrosis, and perinephric abcess.
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chronic pyelonephritis
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A major cause of chronic renal failure. Commonly the result of backward reflux of urine from the bladder to the kidney (reflux nephropathy).
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hypertension
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Blood pressure is determined by cardiac output and peripheral resistance of arterioles. Peripheral resistance is regulated by vasoconstrictors and vasodilators.
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benign (essential) hypertension
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Causes the small renal arteries to become thickened and leads to microscopic ischemic changes which produces glomerular damage, tubular atrophy, and interstitial fibrosis. As scar tissue replaces the damaged renal tissue, the surface of the kidney becomes granular and renal function decreases.
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Malignant hypertension
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Results from an accelerated progression of previously "benign" hypertension and leads to a rapid increase of blood pressure to extremely high levels. Unless treated, death by cardiovascular disease, stroke, or uremia generally follows within a year.
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Renal cell carcinoma (RCC)
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Most frequent form of renal cancer in adults. Usually presents as hematuria with or without a palpable mass. Tumor is usually solitary, bulky, unilateral, and yellow in color with foci of necrosis and hemorrhage. Commonly invades the renal vein. Can metastasize widely, mostly to the lung and bone.
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Wilms' tumor
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Most common primary renal malignancy of childhood. Frequently present as abdominal swelling or large unilateral masses with or without abdominal pain and gross hematuria. Metastasizes to the lung and liver.
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Transitional cell carcinoma
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Arises from the epithelium which lines the calyces and pelvis of the kidney. Tend to produce early hematuria and are therefore identified earlier than renal cell carcinomas.
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Acute renal failure
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Most often due to ischemic or toxic damage to renal tubules (acute tubular necrosis). Oliguria and decreased blood filtration by the glomeruli leads to fluid overlaod, uremia and electrolyte retention. During this phase, patients must be supported by dialysis.
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Chronic renal failure
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When blood filtration is 20-30% of normal, azotemia will develop, freq accompanied by hypertension. Blood filtration decreases further and uremic syndrome takes place.
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azotemia
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increased blood urea, nitrogen, and creatinine.
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uremic syndrom
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Reflects the dysfunctions of many organ systems as well as fluid, electrolyte, and acid/base disturbances.
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Neurons
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the functional units of the nervous system and populate both the CNS and the PNS. They consist of a cell body, afferent dendritic processes, and the efferent axon which in most instances is surrounded by a myelin sheath.
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Astrocytes
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Glial cells which act as stromal (supportive) cells of the nervous system and react to CNS injury.
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Microglia
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Glial cells which function as CNS macrophages.
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Ependyma
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Specialized ciliated glial cells which line the ventricular cavities and central canal of the spinal cord.
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Oligodendroglia
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Glial cells which form myelin sheaths around nerve fibers of the central nervous system early in fetal life. Once the myelin is initially formed, they are necessary to maintain its integrity throughout life but can not replace destroyed myelin.
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Schwann cells
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These cells form and maintain the myelin sheaths around peripheral nerve axons. Unlike the CNS, damage to myelin sheaths around peripheral nerve axons can be regenerated by the Schwann cells.
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Nonspecific CNS reaction to injury
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Cerebral edema which in turn may increase which in turn may increase intracranial pressure (CSF pressure > 200mm H20). Clinical presentation is usually intermittent headache, mental slowness, confusion, and papilledema. The major complication being herniation of the brain.
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papilledema
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Swelling of the optic disc in the eye.
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herniation of the brain
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Brain substance is displaced and compressed against a rigid structure (flax cerebri, tentorium cerebelli, foramen magnum). These are known as subfalcine herniations, uncal herniations, and tonsillar herniations respectively and all may be fatal.
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What produces cerebrospinal fluid (CSF)?
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the choroid plexus
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hydrocephalus
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Occurs when there is an obstruction of CSF flow, an increase in CSF production, or a decrease in reabsorption. If it occurs before the cranial bones fuse in infancy an enlargment of the head occurs. After the bones fuse, acute hydrocephalus will cause symptoms related to increased intracranial pressure.
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Cerebrospinal fluid (CSF)
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circulates through the ventricles of the brain and bathes the outer surface of the brain and spinal cord before being reabsorbed into the venous circulation through the arachnoid granulations.
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Hydrocephalus ex-vacuo
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relates to compensatory ventricular dilation secondary to brain atrophy.
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skull fractures
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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.
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Concussion
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This is a clinical diagnosis characterized by transient loss of consciousness with retrograde and anterograde amnesia. There is minor damage to the brain, but repetitive concussions (football, boxing, etc) can lead to permanent disabling damage.
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Contusion
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superficial areas of necrosis of the cortex resulting from crushing of CNS tissue by blunt force (coup lesions). If the brain strikes the inside of the skull, contrecoup lesions may occur which are a worse contusion than coup lesions. Contusions are most often seen on the inferior surface of frontal lobes, anterior tip of temporal lobes, and occipital poles. These may act as foci of seizure activity (particularly temporal lobes).
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Epidural hematoma
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Refers to hemorrhage into the potential space between the skull and dura mater. Mostly result from tearing of the middle meningeal artery and are located over the temporal and parietal areas. Unless surgically drained, they tend to expand rapidly in volume with ensuing brain herniation and death.
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subdural hematoma
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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. There are acute and chronic subdurals.
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subarachnoid hemorrhage
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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.
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Hypoxic encephalopathy
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This is produced by any process that reduces the effective oxygenation of the brain. Neurologic change depends on the extent and duration of the hypoxia.
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Infarction
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This is the leading cause of "strokes" or cerebrovascular accidents and results from loss of blood supply with ensuing necrosis of the brain tissue.
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vascular thrombosis
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This is usually associated with underlying, pre-existing damage to the vessel wall (atherosclerosis, etc.) and tends to occur within the larger vessels (internal carotid, vertebral, basilar) of older individuals. 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.
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emboli
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Most emboli arise from thrombi within the left heart or carotid arteries. Emboli tend to be multiple and involve smaller vessels and clinically are usually characterized by the sudden onset of neurologic deficit that do not resolve.
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hemorrhage (non-traumatic)
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Accounts for more deaths than infarcts. The most common cause is preexisting systemic hypertension which, over time, weakens the small arteries in the deep white matter of the brain. Hemorrhages are not confined to an arterial distribution, and they tend to compress and disrupt the parenchyma rather than destroy it. The hemorrhage may rupture into the ventricular system, or brain herniation may occur, secondary to the expanding volume of blood.
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saccular ("berry") aneurysms
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Most occur in the middle cerebral artery and its branches and tend to arise at the bifurcation of vessels. Asymptomatic. Spontaneous rupture and hemorrhage may lead to "stroke" or sudden death.
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Bacterial Acute Leptomeningitis
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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. The meninges (surface membranes around the brain) become congested and clouded and purulent exudate may be observed. Neutrophils are seen in the CSF. Common symptoms include agitation, irritability, headache, photophobia, and stiff neck.
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Bacterial Intraparenchymal abcess
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Symptoms are usually related to associated edema, increased intracranial pressure, and local destruction. Without surgical drainage, abscesses tend to expand in size and act as mass lesions with herniation potential.. Rupture into ventricular cavities is usually fatal. Most abscesses have no definable source.
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Viral enterovirus
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These are the most common cause of viral meningitis. This is also the causative agent of poliomyelitis. The infection is 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.
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Herpes Viruses
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These are a family of viruses that, once a person is infected, live 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.
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Rubella
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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.
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Rabies
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Normally an animal disease. Characterized by fever, malaise, and headache which progresses to profound CNS sensitivity (pain, convulsions, photophobia), coma, and death.
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Tuberculosis
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It arises from hematogenous spread from a pulmonary focus. It always results in death if untreated; 30% mortality if treated.
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Syphilis
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The organism enters the CNS hematogenously during the secondary stage of the disease. 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.
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Fungal (Cryptococcus)
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the most common fungal infection of CNS, has insidious onset with headache or behavioral changes and will lead to death if untreated.
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Dementias and Degenerative disease
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Dementia refers to impairment of orientation, memory, intellect, and judgment with associated alterations in mood and behavior. In general, degenerative diseases are incurable and ultimately culminate in the patient’s death.
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Alzheimer disease
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this disease 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. Death is often secondary to other causes such as respiratory infections. The brain shows marked diffuse cortical atrophy due to loss of neurons. This loss of neurons also results in dilatation of the ventricles (hydrocephalus ex-vacuo).
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Huntington disease
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This is an autosomal dominant inherited disease with the initial onset of involuntary muscle movements (choreiform movement) and facial grimaces occurring in mid-adult life. This is followed by personality changes, emotional disturbances, and dementia ultimately leading to death within 10-15 years of diagnosis. The 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.
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Parkinson disease
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This is a 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. Less than half will also develop progressive dementia.
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Amytrophic lateral sclerosis (ALS)
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characterized by gradual progressive motor weakness leading to total paralysis and respiratory failure within 3-5 years.
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Multiple sclerosis
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most common of the demyelinating diseases. It represents an autoimmune reaction against the oligodendroglia that may be triggered by a viral infection with prolonged latent period. clinical symptoms which may include paresthesias, visual disturbances, muscle weakness, in-coordination, and speech difficulties. disease may progress to blindness, incontinence, ataxia, and paraplegia.
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Acute idiopathic polyneuritis (Guillain-Barré)
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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. It may progress to involve the phrenic nerve with paralysis of the diaphragm. These patients must be supported by assisted respiration until the paralysis begins to recede.
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Metabolic storage diseases
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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.
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Neoplastic disease
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All primary CNS neoplasms (arising in the neural parenchyma) are potentially biologically malignant but extraneural metastases are rare. Although the overall incidence of CNS neoplasms tend to increase with age, they represent the second most common group of tumors in childhood. no specific signs or symptoms.
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Meningioma
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This is generally a slow growing, extraneural, benign neoplasm. It arises from cells within the leptomeninges and therefore grows as firm, lobulated, masses on the surface of the brain which compress and indent the underlying brain parenchyma. Symptoms may include headache, focal seizures and visual disturbances.
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Astrocytomas
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These are the most common glial tumors arising in the brain.
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Well differentiated astrocytoma (grade 1)
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This 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.
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Glioblastoma multiforme (grade IV)
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Unfortunately, this highly malignant neoplasm is the most common primary brain tumor in adults. The peak incidence is in the 5th to 6th decade. They 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.
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Metastatic tumors
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Symptoms (headache, seizures, motor deficits, mental changes, etc.) are the result of local expansion and surrounding edema. In order of frequency, primary sites include lung, breast, malignant melanoma, kidney, and gastrointestinal tract. Most metastatic lesions appear in the cortex at the grey-white junction and may be multiple.
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