Uworld: 5-30

Front 1

34 year-old woman
Nausea, abdominal pain, dizziness after minor surgical procedure
1 year h/o chronic corticosteroid therapy
BP 70/40
Pulse 120

Pathophys of presentation

Back 1

Exogenous glucocorticoids suppresses HPA axis (low CRH, low ACTH, low cortisol)

During stressful situations (infections or surgery), normal individuals experience 3 to 9 fold increase in endogenous glucocorticoids. In a suppressed HPA axis, this stress response is lacking and adrenal crisis ensues. In such cases, a higher "stress dose" must be given to compensate.

Front 2

What are the effect of atrial natriuretic peptide?

Back 2

Atrial natriuretic peptide

ANP lowers BP through peripheral vasoDILATION, natriuresis (dilates afferent arterioles-->increasing GFR and urinary excretion of Na/H2O; limits sodium reabsorption in PCT and inhibits renin secretion)

Diuresis (inhibits aldosterone secretion-->inc'd sodium and water excretion)

Front 3

45 year-old male
MVA resulting in pelvic fracture
Unable to void, complains of sensation of full bladder
Foley attempted, but procedure only yields blood without urine

Pathophys

Back 3

Inability to void despite sensation of full bladder suggests urethral trauma.

Foley should not have been attempted.

Pelvic fractures commonly cause hematoma below the prostate with upward displacement of the gland. This affects the posterior urethra (prostatic end of urethra).

Front 4

Vitamin C vs Vitamin K Deficiency:
Presentation

Back 4

Vitamin C:
Hemorrhages
Subperiosteal hematomas
Bleeding into joint spaces
Gingival swelling
Secondary periodontal infection
Anemia
Papular rashes
Impaired wound healing
Weakened immune response to local infection

Vitamin K:
Susceptibility to bleeding, as in gums (minor trauma causes bleeding)--not associated with painful gums

Note: Vitamin C accelerates hydroxylation of prolyl and lysyl hydroxylase precursors--both necessary for hydroxylation of procollagen

Front 5

In a developing nation, advocating early empiric use of penicillin in treatment of clinically diagnosed bacterial pharyngitis would decrease what sequelae?

Back 5

Early treatment of strep pharyngitis can prevent many cases of rheumatic fever.

Repeated stimulus of B cells against Group A Strep (s. pyogenes) that are homologous to self antigens in heart and CNS.

Recurrent untreated GAS pharyngitis will lead to a more rapid onset and increased severity of rheumatic valvular disease.

Eradication of infective streptococci from pharynx prevents subsequent episodes of RF. Drug of choice is PCN.

No PCN resistant strains of S. pyogenes have been detected yet.

Front 6

Which calcium channel blockers result in vasodilation but have no effect on AV conduction?

Back 6

Nifedipine!!

Front 7

Which calcium channel blockers slow conduction through the AV node?

Back 7

Verapamil
Diltiazem

These are both CARDIAC secific

Front 8

Back 8

CT image shows pancreatic PSEUDOCYST--a potential complication of pancreatitis.

Proteolytic enzymes may disrupt walls of pancreatic ducts and cause leakage of pancreatic secretions into peripancreatic space.

This fluid has a high pancreatic enzyme content and induces an inflammatory reaction. Resulting in the formation of GRANULATION tissue, encapsulating the fluid collection and forming a pseudocyst.

NOTE: Unlike true cysts, PSEUDOcysts are not lined by epithelium.

Front 9

List the different immunoglobulins and whether they exist as monomers, dimers, or pentamers.

Back 9

IgG = monomers
IgM = pentamers
IgA = monomers in serum, dimers in mucus, tears, saliva, COLOSTRUM
IgE = monomers

Front 10

40 year-old man
DM I, end-stage renal disease
Prolonged bleeding after replacing dialysis catheter
Has not been dialyzed for several days

Provide values for PT, PTT, PLT count, Bleeding Time

Provide reasoning

Back 10

Hasn't been dialysed in several days, patient is likely uremic.

Bleeding associated with uremia is a QUALITATIVE PLATELET defect: the PLT count, PT, and PTT are normal.

Bleeding time is prolonged.

Front 11

Protease Inhibitors:
AEs

Back 11

Lipodysrophy--inc'd deposition of fat on back and abdomen, dec'd adipose tissue on extremities ("buffalo hump" appearance)

Hyperglycemia due to inc'd insulin resistance

Inhibition of P-450

Front 12

Zidovudine:
AEs

Back 12

Bone marrot toxicity resulting in ANEMIA

Front 13

Acyclovir:
AEs

Back 13

Renal toxicity

Front 14

Foscarnet:
AEs

Back 14

Renal toxicity
Electrolyte disturbances: hypocalcemia, hypomagnesemia, hypokalemia

Front 15

What diseases are prone to developing hypercalcemia secondary to high levels of active vitamin D (calcitriol)?

Back 15

Sarcoidosis
Granulomatous diseases:
-Tuberculosis
-Hodgkin's
-Non-Hodgkin's

Front 16

Keratin is a marker of ______ cell origin.

Back 16

Epithelial

Front 17

Back 17

Downy Cell--EBV
Risk Burkitt's Lymphoma, Nasopharyngeal Carcinoma

Front 18

Ulcer in distal duodenum

Back 18

Zollinger-Ellison Syndrome:
Increased gastrin release causes increased gastric acid secretion by parietal cells

Majority of these tumors located in pancreas

Diarrhea may also occur bc pancreatic and intestinal enzymes are inactivated by gastric acid, so body can't properly digest nutrients

Also note that this may appear with multiple ulcers, ulcers refractory to tx, and recurrence of ulcers after acid-reducing surgery

Front 19

Chronic gastritis with antral sparing

Back 19

Autoimmune gastritis

Front 20

Antral-predominant gastritis

Back 20

H. pylori infection

Front 21

Ulcer in proximal duodenum

Back 21

Peptic Ulcer Disease; gastric ulcers most commonly located at lesser curvature

Front 22

Motor innervation of tongue

Back 22

Hypoglossal

Front 23

Sensation of tongue:
General vs Gustatory

Back 23

General:
Anterior 2/3: Mandibular of Trigeminal
Posterior 1/3: Glossopharyngeal
Posterior area of tongue root: Vagus

Taste:
Anterior 2/3: Chorda tympani of Facial
Posterior 1/3: Glossopharyngeal
Posterior area of tongue root and taste buds of larynx/upper esophagus: Vagus

Front 24

Anti-HTN drug associated with depression

MOA

Back 24

Reserpine:
blocks storage of dopamine, norepinephrine, and serotonin into vesicles, leaving the NTs vulnerable to degradation by MAO within the cytoplasm while the synaptic vesicles remain empty.

Associated with depression and suicidal ideation due to NE and 5HT depleting effects

Front 25

21 year-old male
Sickle Cell Disease
Presents with gross hematuria, which he's never experienced before

Diagnosis
Pathophys
Other causes
Pathologic findings

Back 25

Renal papillary necrosis due to obstruction of renal vessels by sickling-->ischemia

Can also be caused by analgesics (NSAIDs inhibit renal flow by decreasing PG synthesis), DM (non-enzymatic glycosylation causing changes in vascular walls), acute pyelonephritis, UTI (edema compressing medullary vasculature)

Will see gray-white or yellow necrosis of tips of renal pyramids; microscopically exhibit coagulative infarct necrosis

Note: dark, rust-colored or bloody urine and acute, colicky pain are common syx and are due to acute ureteral obstruction from sloughed papillae

Front 26

20 year-old male
Intermittent self-resolving jaundice
Liver biopsy shows abundant pigment inclusions in lysosomes of normal hepatocytes
Pigment composed of epinephrine metabolites

Diagnosis
What type of bilirubinemia would you expect?
Pathophys

Back 26

Dubin-Johnson Syndrome:
Defect in hepatic excretion of BILIRUDIN GLUCURONIDES across canalicular membrane

Presents with CONJUGATED chronic hyperbilirubinemia, NOT A/W hemolysis

Icterus is evident, but most pts asyx

This is a benign condition

Front 27

Outline homocysteine metabolism

Back 27

Front 28

What molecular events occur when a ribosome encounters:
AUG
UAA

Back 28

AUG-->codes for methionine (this is a start codon)

UAA (or UAG, or UGA) is a stop codon-->stop codons do not code for amino acids. INstead RELEASING FACTORS bind to ribosome and stimulate release of polypeptide chain and dissolution of ribosome-mRNA complex.

Front 29

What are the two methods by which radiation therapy kills cancer cells?

What other cells are likely to be affected by this?

Back 29

Radiation induces cell death by:
1) DNA double strand breakage
2) Formation of free radicals. ROS are formed by ionization of water; these oxygen free radicals are then able to cause cellular death and DNA damage

This damage is most pronounced in cells that are rapidly dividing, such as malignant cell, bc they have less of an ability to repair DNA damage induced by radiation.

Bowel mucosa and skin are affected severely bc they are also rapidly dividing.

Front 30

46 year-old female
Diagnosed with SAH on CT
4 days later develops right arm and leg weakness

Diagnosis
Pathophys
Prevention

Back 30

More than half of patients with SAH develop secondary arterial vasospasm. This occurs in vessels surrounding the ruptured aneurysm; causes cerebral ischemia, which presents as new-onset confusion and/or focal neurological deficit 4-12 days after initial insult.

Nimodipine, a selective CCB, is often prescribed to prevent this vasospasm.

Front 31

43 year-old male
Muscle weakness in his hips and shoulders
Muscle biopsy reveals MHC class I molecule over-expression on sarcolemma and CD8+ lymphocyte infiltration

Diagnosis
Pathophys
Relevant Antibody

Back 31

Polymyositis--likely triggered by viral antigens; it's hypothesized that injury causes release of muscle autoantigens that are taken up by macs, presented to CD4+ helper cells. This leads to inflammation.

Inc'd expression of MHC proteins by muscle cells is then presented by myocytes (along with autoantigen) and recognized by CD8+ cells.

This results in muscle inflammation, necrosis, and fibrosis.

A/w Anti-Jo-1
Elevated creatine kinase

Front 32

45 year-old male
Penile lesion
First began as papule
Then several draining ulcers formed
Inguinal pain
Cell scrapings show inclusion bodies

Diagnosis

Back 32

Chlamytdia trachomatis: this is classic for chlamydia: small papule on genital mucosa contains cell infected with C. trachomatis; papule is followed weeks later by swollen, painful inguinal nodes which coalesce, ulcerate, and rupture.

Lymph nodes will demonstrate granulomatous inflammn; this can cause lymphatic obstruction and strictures.

Front 33

75 year-old male
Vision problems
MRI reveals multiple, small lobar hemorrhages in right occipital and left parietal areas
MRI from 1 year ago reveals small, lobar hemorrhage in left frontal area

Diagnosis
Pathophys

Back 33

Recurrent lobar hemorrhages in elderly most likely result from CEREBRAL AMYLOID ANGIOPATHY; this occurs when beta-amyloid is deposited into arterial wall, resulting in weakening of the wall and predisposition to rupture

a/w advanced age and is not related to systemic amyloidosis

Front 34

Male patient with fevers, chills
Dull pain above left knee
No joint effusion
X-ray reveals soft tissue swelling, bone destruction, periosteal reaction over lower end of femur

Diagnosis
How would cause differ by age?

Back 34

If child-->hematogenous osteomyelitis due to Staph aureus

If adult-->due to predisposition for bacteremia such as IVDU or dialysis

Front 35

Describe the four type of renal stones by:
Chemical content
Frequency (general)
Radiolucency
Microscopic appearance/shape

Back 35

Front 36

Depolarizing vs Nondepolarizing neuromuscular junction blocking drugs:
MOA
Speed of Onset (General)
Residual Effects
Examples

Back 36

Depolarizing NMJ blocking drug, often a rapid onset (within 60 seconds); pt will exhibit residual muscle paralysis even after -stigmine (anticholinesterase) administered to reverse action of a NON-depolarizing agent such as vecuronium.

Acetylcholinesterases do not reverse action of depolarizing NMJ blockers and may enhance them.

Example of depolarizing NMJ = succinylcholine

Front 37

When is dantrolene used?

Back 37

Dantrolene relaxes skeletal muscle by reducing Ca2+ from sarcoplasmic reticulum. Used to treat MALIGNANT HYPERTHERMIA after surgery requiring anesthetic.

Front 38

Which adrenergic receptors are present in the uterus?

What is the effect of their stimulation?

Specific drugs that would do this?

Back 38

Adrenergic receptors of uterus belong to beta-2 group whose stimulation leads to uterine relaxation (an effect called tocolysis)

Used in obstetrics to defer premature labor

Need to use adrenergic beta-2 agonists such as TERBUTALINE and RITODRINE

Front 39

Cimetidine side effects (2)

Back 39

Gynecomastia
Inducer of Cyp450

Front 40

66 year-old male with PD
Taking levodopa/carbidopa
Complains of increased motion restriction
Patient is highly compliant

Possible cause?

Back 40

Patient is likely takin a multivitamin, which almost always contain B6.

B6 should not be taken by those on levodopa, because B6 increases peripheral metabolism of levodopa and decreases its effectiveness.

The more peripheral conversion of levodopa, the less levodopa enters the CNS.

Front 41

59 year-old female
Facial swelling, difficulty breathing
Patient recently began taking captopril

Diagnosis
Pathophys

Back 41

This is angioedema (a symptom of anaphylaxis)--involves swelling of tongues, lips, or eyelids. Patients can also experience laryngeal edema and difficulty breathing.

Believed to be due to bradykinin accumulation.

Front 42

Assuming continuous infusion, how long does it take for a drug with first-order kinetics to achieve steady state concentration?

Back 42

4-5 half-lives

Front 43

In RHD, what physiologic changes occur solely to mitral stenosis?

What findings might indicate an additional process? What could that process be?

Back 43

In isolated mistral stenosis, diastolic pressure in the LV is normal. Only pressures PROXIMAL to the mitral valve are elevated.

When a patient with suspected MS is also found to have an increased LVEDP, an additional lesion is likely.

Possibilities include rheumatic involvement of the aortic volve (which typically causes aortic stenosis AND regurgitation) or infective endocarditis superimposed on aortic valve deformed by RHD.

in RHD, mitral valve alone is sole site of involvement in up to 70% of cases.

Front 44

Diagnosis
Pathophys

Back 44

Significantly enlarged kidney with dilatation and deformation of the calices and renal pelvis-->HYDRONEPHROSIS

Due to obstruction of urine flow. Most common cause of urinary tract obstruction (in elderly male) is BPH.

Other causes include nephrolithiasis, anatomic abnlty, pregnancy, neurogenic bladder

Front 45

Linear vs Lumpy granular deposits of IgG/C3

Back 45

Linear = Goodpasture's
Lumpy = PSGN

Front 46

Describe the events of intrinsic and extrinsic apoptosis.

Back 46

Extrinsic:
TNF bound to TNF receptor 1 or Fas ligand to Fas
Pro-caspase molecules brought into close proximity
Caspases are activated and cleave aspartate residues (note caspases contain cysteine; it's the c in caspase)

Intrinsic:
UV light, heat, hypoxia, toxins, etc display intrinsic apoptotic signals

Balance of pro-apoptotic (Bak, Bax, Bim) and anti-apoptotic (Bcl-2, Bcl-x) proteins is pushed toward Bak, Bax, Bim.
Mitochondria becomes permeable and releases cytochrome c into cytoplasm
Cytochrome c activates caspases
Caspases cleave aspartate residues

Front 47

Moldy grains:
Risks
Specific mutation

Back 47

Specific strains of Aspergillus grow on foods such as corn, soybeans, and peanuts, producing AFLATOXINS

High levels of dieatary aflatoxin exposure is associated with G to T mutation in p53

Increases risk of developing hepatocellular carcinoma

Front 48

Painless gross hematuria

Back 48

Bladder cancer

Front 49

What is the effect of CO on the oxygen-dissociation curve for hemoglobin?

Back 49

Leftward ***** (inc'd affinity)

Front 50

What is primary biliary cirrhosis?
Antibody?

Back 50

Autoimmune disease of the liver causing progressive destruction of the small bile ducts (bile canaliculi) within the liver.

When these ducts are damaged, bile builds up in liver (cholestasis) and over time damages the tissue.

This can lead to scarring, fibrosis, and cirrhosis.

Can lead to xanthoma! (Collection of cholesterol in skin, esp around eyes)

Anti-Mitochondrial Antibody (AMA)

Front 51

58 year-old male
Diffuse gallbladder calcification

Diagnosis
Risks

Back 51

Porcelain gallbladder; up to 33% of patient population will develop gallbladder carcinoma

Front 52

18 year-old male
Right-sided chest pain, dyspnea
Tall, thing patient in acute distress
Right chest is hyperresonant to percussion, lacks audible breath sounds

Diagnosis
Pathophys

Back 52

Primary spontaneous pneumothorax

Thought to result from rupture of apical subpleural blebs--blebs are continuous, distended airspaces and sometimes form cyst-like sacs.

Blebs may spontaneously rupture, usually while pt is at rest, causing a pneumothorax. Tall, thin males around age of 20 are most commonly affected.

Front 53

Describe the role of carbonic anhydrase in RBCs.

Back 53

CO2 produced by tissue respiration enters RBCs and via carbonic anhydrase is hydrated to form HCO3 and H2O.

Many bicarb ions diffuse out of RBC into plasma.

To maintain electrical neutrality, Cl- ions diffuse into the RBC to take place of HCO3. THis process is called "chloride shift", and it the reason RBC Cl- content is higher in venous blood.

Front 54

B. anthracis:
Toxins and effects
What other bacterium exhibits a similar toxin effect?

Back 54

Edema factor--causes increase in cAMP concentration within host cells; important for suppression of nphil fn and accumuln of fluid with and between cells (leading to edema)

Bordetella pertussis also produces an edema factor-like exotoxin called "extracellular adenylate cyclase"; causes dramatic increase in cAMP levels leading to nphil dysfn just as edema factor does

Note: B anthracis also has an antiphagocytic poly-gamma-D-glutamic acid capsule

Front 55

45 year-old female
Severe pruritis at night
Elevated alkaline phosphatase

Diagnosis

Back 55

Primary Biliary Cirrhosis

Front 56

Back 56

For parallel circuits:

1/Rtotal = 1/R1 + 1/R2 + 1/R3...1/Rn

Therefore:
1/Rtotal = 1/2 + 1/2 +1/2 +1/2
= 2

Rtotal = 0.5 mmHg/ml/min

Front 57

30 year-old male
Exertional dyspnea
Liver biopsy shows PAS-positive intracellular inclusions

Diagnosis
Pathophys

Back 57

Homozygous for alpha-1 antitrypsin deficiency which inhibits proteolytic enzyme

Will develop panacinar emphysema secondary to DESTRUCTION of alveolar walls

May also develop cirrhosis and hepatocellular carcinoma due to granules of unsecreted alpha-1 antitrypsin building up in hepatocytes.

Front 58

What is the best kind of question to ask patients (in order to elicit most important information)?

Back 58

Open-ended questions:
"What brings you in today?"
"Tell me more."
"How can I help you?"

Front 59

30 year-old male
HIV positive
IVDU
Presents with abdominal distention, anorexia, ascites
CT reveals large mass surrounding small intestine
Biopsy reveals uniform, round tumor cells with basophilic cytoplasm
Ki-67 fraction (mitotic index) >99%

Diagnosis
Cause
Specific mutation

Back 59

This is Burkitt lymphoma--most strongly associated with Epstein-Barr virus.

Crucial step in transformation is balanced t(8;14) translocation which causes overexpression of c-MYC (a transciptional regulator that controls cell proliferation)

Chronic EBV infection increases B cell proliferation and increases risk of C-myc translocation

High proliferation index represented by Ki-67 (approaching 100%)--in addition to a starry sky appearance--is classic for Burkitt's