Uworld: 5-21

Front 1

18 year-old male
Fever, confusion, nausea 4 days after general anesthesia
Elevated AST, ALT, bilirubin

Diagnosis
Pathophys
Histologic Findings

Back 1

Halothane-associated hepatitis

Halogenated inhalation anesthetics (halothan, enflurane, isoflurane, sevoflurane) can cause cause severe liver damage. Esp. halothane bc it's most extensively metabolized in liver.

Light microscopy will reveal widespread hepatic necrosis due to direct liver injury by halothane metabolites and formation of autoab's x liver proteins.

Front 2

How do gram-positive bacteria differ from gram-negative bacteria (structurally/functionally)?

Back 2

Gram positive organisms have a cytoplasmic membrane composed of phospholipid bilayer IN ADDITION to a peptidoglycan cell wall outside of that cell membrane.

The peptidoglycan cell wall provides shape of bacterium as well as resistance to osmotic stress.

Front 3

Which antibiotics inhibit the 30S bacterial ribosome subunit?

50S?

Back 3

30S: Tetracyclines, Aminoglycosides

50S: Chloramphenicol, Macrolides

Front 4

Which antibiotics disrupt the peptidoglycan cell wall of Gram-positive and Gram-negative organisms?

Back 4

PCN
Cephalosporins
Vancomycin

Front 5

What is the most common cause of fetal hydronephrosis (embryological processes, specific region of hydronephrosis)?

Back 5

During development, the ureters are fully canalized before the metanephros (which branches to form the collecting ducts, calices, renal pelvis, ureters, and renal parenchyma) begins to produce urine.

Occasionally, the metanephros will begin producing urine before canalization of the ureteric bud is complete and this leads to a transient hydronephrosis.

Occurs at the ureteropelvic junction (junction between kidney and ureter--last of the ureter to canalize).

Front 6

55 year-old woman
s/p cholecystectomy
Sudden onset nausea, fever
Viral serologies negative
Liver on autopsy

DIagnosis
Pathophys
Lab values

Back 6

Inhaled anesthetics, such as halothane, can be associated with lethal fulminant hepatitis that cannot be histologically distinguished from acute viral hepatitis.

Labs will show elevated ALT, prolonged PT time, and elevated eosinophils.

Front 7

How does the presentation of acute liver disease differ from chronic liver disease?

Back 7

Acute: Prolonged PT time, elevated ALT

Chronic: Dec'd albumin (albumin has a half life of 20 days so acute liver failure won't affect it), palmar erythema, ascites, splenomegaly

Front 8

A new drug for treating stable angina has been developed. It inhibits a step in fatty acid oxidation.

What is the most likely MOA explaining its potential benefit?

Back 8

Energy for mitochondrial cells mostly comes from fatty acid oxidation in mitochondria (other source =glycolysis, glucose oxidation).

However, fatty acid oxidation requires more oxygen use in comparison to glucose utilization and glycolysis.

It's believed that in stable angina, atherosclerosis leads to reduced O2 delivery to cardiac mitochondria, leading to mismatch between mitochondrial O2 demand and supply.

Since glucose oxidation requires less O2, it's believed that inhibiting mitochondrial FA oxidation will shift energy production to glucose oxidation (which would be more O2 efficient).

Front 9

What risk does a retained dead fetus pose to a pregnant mother?

Back 9

DIC and progressive hypofibrinogenemia

Front 10

What are the laboratory findings of DIC?

Back 10

Prolonged PTT, PT
Low PLT and microangiopathic hemolytic anemia
Low fibrinogen
Elevated fibrin split products (D-dimer)
Low Factor V and VIII levels

Front 11

Drugs of choice for absence seizures
MOA?

Back 11

Ethosuximide--blocks T-type Ca2+ channels in thalamus

Valproate--blocks T-Type Ca2+ channels AND Na+ channels

Front 12

Drugs of choice for absence seizures in addition to tonic-clonic seizures
MOA?

Back 12

Valproate--blocks T-type Ca2+ channels and Na+ channels

Front 13

Phenytoin:
MOA
Specific Use

Back 13

Inhibits high frequency firing of Na+ channels

Use in TONIC-CLONIC and STATUS EPILEPTICUS

Front 14

ACE inhibitors:
Potential metabolic disturbances

Back 14

ACE inhibitors decrease aldosterone secretion and as a result increase Na+ excretion and potassium retention (HYPERKALEMIA)--not common unless in renal failure or taking K+ sparing diuretic

Front 15

56 year-old male
Long history of dyspnea, wheezing, cough
Smoked 2 ppd x 25 years
Has been treated with antibiotics when dyspnea is severe

Diagnosis

Back 15

Chronic bronchitis caused by smoking and exacerbated periodically by superimposed bacterial bronchitis

Front 16

What is the Reid index?
What does it indicate?

Back 16

Reid Index = ratio of thickness of mucus gland layer in bronchial wall submucosa to thickness of bronchial wall between cartilage and respiratory epithelium

It essentially measures mucus gland enlargement

Since progressive mucus gland enlargement is the major contributor to bronchial wall thickening in chronic bronchitis (and since increasing wall thickness causes worsening airflow obstruction), elevation of the Reid index above 40% correlates with duration and SEVERITY of CHRONIC BRONCHITIS.

Front 17

What are the specific actions of aldosterone?

Back 17

Increases Na and H2O reabsorption in COLLECTING DUCTS by increasing number of Na/K-ATPase proteins and sodium channels in collecting ducts.

Thus sodium and water are rmemoved from tubular fluid both actively and passively.

AS a consequence, K+ and H+ are lost into collecting tubules via secretion from intercalated cells.

Front 18

Osteoporosis:
General definition
Type of bone involved

Back 18

Loss of total bone mass due to trabecular thinning

Note: trabecular = spongy bone

Front 19

10 year-old male
Headaches, nose bleeds
Difficulty walking
Pulsatile vessels palpable along ribs

Diagnosis
Pathophys of findings

Back 19

Adult type (postductal) congenital aortic coarctation

Headaches and epistaxis due to HTN in aa supplying head and neck

Lower extremity muscle weakness/fatigue due to inadequate lower body perfusion

Paplpable intercostal vessels indicate development of collateral arterial circulation to region of aorta distal to coarctation

Front 20

When specifically does an S4 heart sound arise?
Why?

Back 20

S4 is heard when there's a sudden rise in end diastolic ventricular pressure caused by atrial contraction against a STIFF LEFT VENTRICLE (ventricle has reached limit of its compliance).

LV stiffness can be due to:
Degenerative mitral calcification
Aortic valve calcification
HTN disease leading to LVH

Front 21

Esophageal biopsy--
Diagnosis

Back 21

Adenocarcinoma; arrow is pointing to columnar epithelium w/goblet cells (intestinal epithelium). This is diagnostic of Barrett esophagus.

Front 22

3 year-old male
Recurrent dyspnea relieved by squatting

Diagnosis

Back 22

TOF

Front 23

What are the findings of tetralogy of Fallot?

Back 23

PULMONARY STENOSIS (NOT PDA)
RVH
Overriding Aorta
VSD

Front 24

List the characteristics of drugs that affect the volume of distribution.

Provide the correlating volume of distribution.

Back 24

Average total body water is 41 L
ECF volume is 1/3 = 14 L
Plasma volume (within ECF) = 3L


If drug has large molecular weight, is bound by plasma proteins, or is highly charged (hydrophilic), remains in plasma compartment and Vd: 3-5L

If drug has small moelcular weight but is charged (hydrophilic), can distribute ti interstitial fluid as well as intravasc compartment; Vd = 14-16 L

If drug has small MW and is uncherged (hydrophobic/lipophilic), can cross cell membranes and reach intracellular compartment; Vd = 41L

Front 25

Significance of low/high AFP during pregnancy.

Back 25

Low AFP: Trisomy 21

High AFP: multiple gestation, NT defects (including spina bifida, anencephaly), omphaloceles and other abdominal wall defects

Front 26

49 year-old female
Ovarian mass with yellow coloration
Diagnosed as granulose-theca cell tumor

What is it likely to secrete?
Effects?

Back 26

Likely to secrete estrogen and not androgens.

This will cause precocious puberty in prepubertal girls or fibrocystic change of breast, endometrial hyperplasia/carcinoma in older women.

Front 27

Describe the general path copper takes once ingested.

Back 27

Copper is absorbed in stomach/duode, transported to LIVER via albumin

Within liver, it forms ceruloplasmin

Senescent ceruloplasmin and remainder of ingested, unabsorbed copper are secreted into bile and excreted in stool (primary route for copper elimination)

YOU POOP IT OUT VIA YOUR LIVER

Front 28

Which CNS tumors stain positively for synaptophysin?

Back 28

Remember: synaptophysin is a protein found in presynaptic vesicles of neurons, neuroendocrine and neuroectodermal cells.

So CNS tumors of NEURONAL ORIGIN will stain positive for synaptophysin.

Front 29

Which CNS tumors stain positively for glial fibrillary acidic protein?

Back 29

CNS tumors of GLIAL origin: astrocytoma, ependymomas, oligodendrogliomas stain positively for GFAP

Front 30

35 year-old female
Weakness, fatigue, pallor
Low RBCs
Retic 0.1%
BM biopsy reveals absence of erythroid precursors but preserved myeloid and megakaryocytic elements

Diagnosis
Pathophys
Disease associations

Back 30

Pure red cell aplasia is a form of marrow failure characterized by hypoplasia of marrow erythroid elements in setting of normal granulopoiesis and thombopoiesis.

It is associated with THYMOMAS and PARVOVIRUS B19

Front 31

Describe the embryonic formation of the pancreas (doral vs ventral buds).

How does pancreatic divisum arise? Clinical effects?

Back 31

Dorsal bud forms majority of pancreatic tissue (body, tail, most of head)

Ventral pancreatic bud forms the uncinate process, inferior/posterior portion of the head, and major pancreatic duct***

Failure of the dorsal and ventral buds to fuse leads to pancreas divisum where 2 pancreatic ducts open into duodenum (clinically silent; may predispose to dev't of recurrent pancreatitis).

Front 32

What are the symptoms of narcolepsy?

Back 32

Excessive daytime sleepiness with sleep attacks

Hypnagogic (hallucinations while falling asleep) or hypnopompic (hallucinations on waking up) hallucinations

Cataplexy (paralysis after laughter/surprise)

Sleep paralysis

Front 33

Contrast Crohn's Disease with Ulcerative Colitis in terms of:
Region of bowel involved
Light microscopy findings
Clinical manifestations
Intestinal complications

Back 33

Front 34

32 year-old male
Vague abdominal pain
Fever, diarrhea
No response to antibiotics
Enterocutaneous fistula

DIagnosis

Back 34

Crohn's (due to transmural inflammn-->fistula)

Front 35

What side effects of opioid use are most resistant to developing tolerance?

Back 35

Constipation
Miosis (pinpoint pupils)

In other words, won't get used to constipation! Need to give laxatives and keep hydrated.

Front 36

Granuloma in lungs:
2 causes

Back 36

Tb
Sarcoidosis

Front 37

A study of 400 patients hospitalized with DM-related complications shows that serum cholesterol level is a normally distributed variable with a mean of 220 mg/dL and standard deviation of 10 mg/dL.

Based on the study results how many patients do you expect to have serum cholesterol ≥240 mg/dL in this study?

Back 37

240 is 2 SD above mean
So, 95% of patients will be within 2 SD, that is, 95% of patients will be in the range of 200-240 (2SD's in both directions).

5% will be below 200 + above 240.

Cut this in half and you have your answer: 2.5% will be above 240.

Front 38

What auscultatory finding would indicate severe mitral regurgitation (beyond holosystolic murmur)?

Why?

Back 38

An S3 heart sound

LV S3 gallop indicates increased rate of filling of LV during MID diastole. If there is a high volume of regurgitant flow recycled back into LV during diastole, you will hear an S3.

Front 39

This heart sound is heard when the left ventricle is dilated.

Back 39

S4--predecessor to ventricular failure!!

Front 40

This heart sound is heard when the left ventricle receives too much fluid during diastole.

Back 40

S3

Front 41

Calculate the net filtration pressure given:
Glomerular capillary hydrostatic pressure = 45 mmHg
Glomerular capillary oncotic pressure = 27 mmHg
Bowman capsule hydrostatic pressure = 10 mmHg
Bowman capsule oncotic pressure =2 mmHg

Back 41

Net filtration pressure = (Pc - Pi) - (πc - πi)

= (45-10) - (27-2)
=35-25
=10 mmHg

Front 42

34 year-old man
Fever, chills, dyspnea
h/o MVA with emergent laparotomy (2 years ago)
BP 80/40
Blood cultures gros S. pneumo

Why?

Back 42

Patient likely experienced splenic rupture secondary to abdominal trauma 2 years ago, with splenic remnants removed during laparotomy.

Now has impaired bacterial clearance of encapsulated organisms.

Front 43

What is status epilecticus?

Back 43

Recurrent or continuous tonic-clonic seizures that last for more than 30 minutes without a return to consciousness. LIFE-THREATENING.

Front 44

What is the treatment algorithm for status epilecticus?

Include the reason for administering each drug in addition to its MOA.

Back 44

Front 45

Riboflavin:
B vitamin number
Signs of deficiency
Reaction and enzyme that requires it

Back 45

Riboflavin = B2

Deficiency = oral lesions at corners of mouth, anemia, glossitis, eye changes (keratitis, corneal neovascularization)

B2 is a precursor of FMN and FAD

FAD participates in TCA as a coenzyme of SUCCINATE DH, which converts Succinate into Fumarate

Front 46

VHL Disease:
Presentation
Genetic cause (specific mutation)

Back 46

Cerebellar hemangioblastomas
Renal clear cell carcinoma
Pheochromocytoma

VHL Mutation on chromosome 3p

Front 47

Chemotherapeutic that causes:
Finger numbness/tingling

How?

Back 47

Vinblastine, Vincristine-->interferes w/MT formation in nerve axons

(Affects mitotic spindle; M-phase specific agents)

Front 48

Chemotherapeutic that causes:
Burning on urination and urgency

Back 48

Cyclophosphamide or ifosfamide; prevent with mesna

Front 49

Chemotherapeutic that causes:
Led swelling and orthopnea

Back 49

These are signs of heart failure.
Chemo that causes cardiotox = Doxorubucin (intercalating agent)

Front 50

Chemotherapeutic that causes:
Dry cough and exertional dyspnea

Back 50

Bleomycin (pulmonary fibrosis)

Front 51

What regions of the brain are supplied by the ACA, MCA, and PCA?

Back 51

Front 52

How can fecal-oral viruses be destroyed (in event of contamination)?

Back 52

Water chlorination (bleach 1:100 dilution)
Formalin
UV irradiation
BOILING for one minute

Front 53

Duodenal ulcer relieved by food

Diagnosis
Cause

Back 53

Peptic Ulcer Disease caused by H. pylori (or NSAID use)

Front 54

Thrombophlebitis:
What is it?
What does it mean?

Back 54

Thrombophlebitis is inflammation of a vein due to a blood clot.

ALWAYS THINK CANCER. It's very common in adenoca of pancreas, colon, lung.

Hypercoagulability occurs bc adenoca produce thromboplastin-like substance capable of causing intravasc coagulations that tend to migrate.

This is called paraneoplastic syndrome.

Front 55

What is migratory superficial thrombophlebitis?

Back 55

When patient with visceral cancer is in a hypercoagulable state and multiple sites of thrombophlebitis occur. Or one resolves and recurs in another site.

Front 56

Spoon-shaped nails

Back 56

Iron deficiency anemia

Front 57

Glomerular basement membrane exhibits irregular spikes

Diagnosis
Pathophys

Back 57

Membranous glomerulopathy (common cause of nephrotic syndrome in adults)

Can occur secondary to underlying malignant tumors, infections (HBV, HCV, malaria, syphilis), certain meds (gold, penicillamine, NSAIDs).

Diffuse inc'd thickness of GBM on light microscopy (without hypercellularity), SPIKE AND DOME APPEARANCE, and granular deposits are diagnostic.

Front 58

56 year-old man
Colon cancer
Generalized edema
Urine protein excretion 4.5 g over 24 hours

Diagnosis
Pathophys

Back 58

Nephrotic syndrome (losing protein) likely due to membranous glomerulopathy (likely due to underlying malignancy)

Front 59

Crescendo-decrescendo murmur:
Diagnosis
Cause
Specific Physical Exam Findings

Back 59

Diamond-shaped murmur = AORTIC STENOSIS

MOst common cause = calcification of aortic valve leaflets

Physical exam will reveal pulsus parvus et tardus (small and slow rise in carotid pulse during systole)

Front 60

Outline the urea cycle.
Include nitrogen source and the rate limiting step.

Back 60

Mitochondria:
CO2 + NH4 + 2ATP + N-ACETYLGLUTAMATE (activates CPS I)
-->
Carbamoyl phosphate (via CPS I)

Carbamoyl phosphate-->Citrulline-->Cytosol

Citrulline + Aspartate (NITROGEN SOURCE)

-->-->Urea + Ornithine

RLS = CPS1