Uworld: 5-10

Front 1

How does liver failure result in gynecomastia?

What other symptoms arise as a result of this?

Back 1

Liver unable to metabolize circulating estrogens (specifically, androstenedione)-->hyperstrinism

In EtOH liver dz-->inc'd sex hormone-binding globulin (Increases T:E ratio)

Also results in:
-Testicular atrophy
-Dec'd body hair
-Spider angiomata

Front 2

What cells/regions of the brain is most sensitive to cerebral ischemia?

Back 2

Pyramidal cells of hippocampus, neocortex

Purkinje cells of cerebellum

Front 3

alpha1-antitrypsin:
Role

Back 3

Inhibits elastase in lungs

Front 4

What is necessary for phosphorus absorption in the gut?

Back 4

Vitamin D

Front 5

Patient eats more than usual
Feels guilty and depressed
Vigorously exercises
Has had similar episodes for 5 months
BMI is 23.7

Diagnosis
Why?

Back 5

Bulimia nervosa; not body dysmorphic disorder.

In body dysmorphic disorder, patients have an intense preoccupation with imagined bodily defects which leads to FUNCTIONAL IMPAIRMENT.

In bulimia, there's binge-eating with either restrictive or purging compensatory behaviors. Normal BMI. This description fits the bill.

Front 6

Adenosine deaminase:
Role
Effects of deficiency

Back 6

Adenosine deaminase:
-present in all cells; deminates adenosine to eliminate excss adenosine from cell

-adenosine accumulation is toxic to lymphocytes

-deficiency leads to widespread death of both T and B cells with resultant combined cellular and humoral immunodeficiency (SCID!)

Front 7

Patient hypotensive and bleeding from MVA
Receives blood transfusion
Develops dyspnea, chills
Goes into renal failure

Pathophys

Back 7

Acute hemolytic reaction with blood transfusion due to ABO incompatibility.

Anti-ABO antibodies in recipient bind antigens on donor erythrocytes.

Ag-Ab complexes activate COMPLEMENT, results in production of C3a and C5a (ANAPHYLATOXINS) as well as MAC (C5-C9_-->SHOCK

THIS IS A HYPERSENSITIVITY TYPE II REACTION

Front 8

Stroke
Sensory loss on right side of body
Unsteady gait

Diagnosis

Back 8

Thalamic syndrome--infarct of left thalamus (CONTRALATERAL)

Front 9

s/p MI
5mm cavities in deep brain filled with clear fluid

Diagnosis
Pathophys

Back 9

Lacunar infarctions (within basal ganglia, pons, cerebellum, ~5mm)

Result of small vessel lipohyalinosis (destructive vessel lesion) and atherosclerosis; most common in setting of uncont'd HTN and DM.

Front 10

Label

Back 10

Front 11

KOH test
Positive whiff test

Back 11

Bacterial vaginosis

Front 12

Somatomedin C:
Role

Back 12

AKA IGF-1

Inc'd when GH released from pituitary; causes differentiation and proliferation of chondrocytes in epiphyseal growth plate (increase in linear growth)

Unlike, estrogen, does NOT accelerate epiphyseal closure.

Front 13

Diagnosis
Epidemiology
Pathophys
Surgical Considerations
Treatment

Back 13

Hydatid cyst formed by tapeworm Echinococcus granulosus

Occurs in Mediterranean, South Amera, Middle East, Australia/New Zealand, Southern Africa

Dog = part of tapeworm lifecycle (can affect Americans that work with sheep dogs)

Tx with albendazole or mebendazole

DO NOT ASPIRATE--spilling of cyst contents within peritoneum can cause anaphylaxis

Front 14

What do schistocytes suggest?

Back 14

Microangiopathic hemolytic anemia (TTP, HUS, DIC) or mechanical damage)

Front 15

Bloody diarrhea
Anemia
Thrombocytopenia
Normal PT/PTT
Schistocytes

Diagnosis
Pathophys

Back 15

Hemolytic uremic syndrome (a form of microangiopathic hemolytic anemia)

Undercooked ground beef-->Enterohemorrhagic E. coli-->Shiga toxin-->bloody diarrhea

Endothelial cell injury-->activation of platelets and formation of microthrombi

While passing by, RBCs are damaged by microthrombi and appear as schistocytes.

Unlike in DIC, coagulation system is not active, so PT and PTT normal.

(not sure why shiga toxin is necessary, but bloody diarrhea usually precedes childhood HUS)

Front 16

How does hemolytic uremic syndrome (HUS) differ from thrombotic thrombocytic purpura (TTP)?

Back 16

HUS and TTP both present with:
-fever, neurologic syx renal failure, thrombocytopenia, microangiopathic hemolytic anemia

Usually, TTP occurs in adults with predominant neurologic syx

HUS, in children with primarily renal involvement (renal failure)

Front 17

What is radial traction?

Back 17

Outward pulling

Front 18

Restrictive lung disease:
Examples
Lung Test Values
Effect on recoil, radial traction

Back 18

Restrictive lung disease = pulmonary fibrosis

Dec'd TLC, VC, Inspiratory capacity
Dec'd FEV1, FVC
Inc'd FEV1/FVC bc FEV1 dec'd less than FVC

Relatively high expiratory rate due to dec'd lung compliance (inc'd elastic recoil) and inc'd radial traction (outward pulling) exerted on conducting airways by fibrotic lung

Front 19

Where is the majority of total frictional airway resistance localized?

How does this change as air progresses through the respiratory airways?

Back 19

Majority of resistance at medium and small-sized bronchi greater than 2mm in diameter.

Regional airway resistance is maximal in 2nd-5th generation of airways (there are 23 generations of branching total).

Airway resistance is minimal in bronchioles.

Front 20

Aldolase B participates in _______ metabolism.

Back 20

Fructose

Front 21

Maltose is broken down into ______.

Back 21

Glucose and Glucose

Front 22

Lactose is broken down into ______.

Back 22

Galactose and Glucose

Front 23

Sucrose is broken down into ______.

Back 23

Fructose and Glucose

Front 24

The majority of cervical cancers are _______.

Back 24

Squamous cell carcinomas

Front 25

Overexpression of viral proteins E6, E7:
Viral association
Effects

Back 25

HPV-16,18 (HIGH RISK)

E6: binds p53 and decreases its degradation
E7: binds Rb and displaces transcription factors normally bound to it

Front 26

Stop codons

Back 26

UAG
UAA
UGA

You're a goat
You're an ass
You're a goat's ass

Front 27

Causes of left/right shifts of oxygen-dissociation curve.

Back 27

Left shift:
Increased affinity for oxygen, caused by:
-Dec'd H+ (inc'd pH)
-Dec'd 2,3-DPG
-Dec'd temp

Right shift:
Dec'd affinity for oxygen caused by:
-Inc'd H+ (dec'd pH)
-inc'd 2,3-DPG
-Inc'd Temp

Front 28

What is the effect of strenuous exercise on the oxygen-dissociation curve?

Back 28

Exercise-->inc'd CO2-->dec'd pH (inc'd H+)
Right shift (dec'd affinity for O2)

Front 29

Exhibits IgA protease

Back 29

Strep pneumo

Front 30

Hemolysin:
Effects
Associated bacteria

Back 30

Staph--secreted factor, not bound fo cell wall

Effects: produces hemolysis and destruction of nphils, macs, PLTs

Front 31

Protein A:
Effects
Associated bacteria

Back 31

Protein A = characteristic of Staph aureus

Binds Fc portion of IgG and prevents activation of complement

Results in dec'd production of C3b-->impaired opsonization

Front 32

D-alanine-D-alanine analog that prevents bacterial peptidoglycan cross-linking

Back 32

Cell wall inhibitor!!

D-ala-D-ala = substrate of PCN binding protein (bacterial enzyme targeted by PCNs)

Front 33

Why is penicillin not effective against mycoplasma?

What agents are effective?

Back 33

Mycoplasma lack peptidoglycan walls so cell wall inhibitors like PCN, cephalosprins, vanco, etc. won't work.

Mycoplasma has a single phospholipid bilayer with cholesterol; just like human cells.

Need to use anti-ribosomal agents like macrolides and tetracyclines.

Front 34

These bacteria lack peptidoglycan walls and are similar in structure to human cells.

Back 34

Mycoplasma
Ureaplasma

Front 35

Inferior wall infarct appears in these EKG leads.

Artery affected?

Back 35

II, III, aVF

Occlusion of RCA

Front 36

Anteroseptal infarct appears in these EKG leads.

Artery affected?

Back 36

V1-V4

Proximal LAD

Front 37

Lateral wall infarct of left ventricle appears in these EKG leads.

Artery affected?

Back 37

V5, V6

Left Circumflex

Front 38

Draw a ventricular muscle action potential.

Label and describe what happens during every phase.

Back 38

Phase 4: Resting potential (diastole)--permeability to K+ ions in resting state.

Phase 0: Rapid depolarization: Voltage-gated Na+ channels open and Na+ ions rush into cell

Phase 1: Initial rapid repolarization: rapid closure of Na+ channels

Phase 2: Plateau: L-type dihydropyridine-sensitive Ca2+ channels open, some K+ channels close (membrane becomes highly permeable to Ca2+, minimally permeable to K+)

Phase 3: Late phase repolarization: Closure of Ca2+ channels; opening of K+ channels. Efflux of K+ from cell restores membrane resting potential.

Front 39

Which clotting factors are vitamin K dependent?

Back 39

II, VII, IX, X

Front 40

Rodenticide ingestion:
Effect
Treatment

Back 40

Rodenticides contain brodifacoum, a 4-hydroxycoumarin derivative, i.e., A VITAMIN K ANTAGONIST

This depletes patients of vitamin K dependent clotting factors, causing acquired coagulopathy.

RISK OF GI BLEEDING (POTENTIALLY FATAL)

Must replenish factors through IV fresh frozen plasma. Vitamin K1 also.

Front 41

Heparin OD:
Treatment

Back 41

Protamine

Front 42

Patient taking amphotericin B
EKG reveals PVCs

Pathophys

Back 42

Amphotericin B is nephrotoxic

Causes dec'd GFR, has direct toxic effects on tubular epithelium

Causes hypokalemia, hypomagnesemia (due to inc'd memnbrane permeability of distal tubule)

These metabolic disturbances can result in arrhythmias (hypokalemia = T wave flattening, PACs, PVCs; if profound-->Vfib/Vtach)

Front 43

Infection with delta agent:
Pathophys

Back 43

delta agent = Hepatitis D

By itself, HDAg is replication-defective; must be COATED by HBsAg of HBV before it can infect hepatocytes and multiply.

HDV can either arise as acute coinfection with HBV or as superinfection of chronic HBV carrier.

Front 44

GABA-a vs GABA-b vs GABA-c:
Functions
Associated drugs

Back 44

GABA-a: ion channel (bound by benzodiazepines, barbiturates, EtOH)

GABA-b: linked to G-protein

GABA-c: ion channel

Front 45

What vitamin must be supplemented with INH use?

Why?

Back 45

Pyridoxine (B6)

INH is structurally similar to pyridoxine. As a result, increases urinary excretion of pyridoxine and competes for its binding sites, leading to defective synthesis of GABA. Can induce NEUROPATHY.

Front 46

Mifepristone:
MOA
Use
AEs

Back 46

"Anti-progestin"
Progesterone antagonist (has 5 times the affinity for PG receptor than natural PG)

PG necesary for implanatation and maintenance of pregnancy. When antagonized by mifepristone-->decidual necrosis and expulsion of products of conception.

Anti-progestin effects induce release of endogenous Prostaglandins-->abdominal cramps, nausea, vaginal bleeding

Front 47

Spatial vs Temporal Summation:
General

Back 47

Spatial: impulses from several different neurons

Temporal: sequential impulses from same neuron over time

Front 48

What is the space constant?
What increases it?
Decreases it?

Back 48

Measure of how far along an axon an electrical impulse will travel.

Increased by myelin, decreased by demyelination (MS)

Front 49

Describe the following presentations of 21-OHase deficiency:
Non-classic
Classic, non-salt wasting
Classic, salt-wasting

Back 49

Non-classic, delayed:
Mild degree of 21-OHase deficiency
Present with premature pubarche or sexual precocity

Young women can present with acne, hirsutism, menstrual irregularity

Classic, non-salt-wasting:
Moderate degree of 21-OHase deficiency

Females present at birth with ambiguous genitalia

Males present at 2 to 4 years with signs of early virilization

Classic, salt-wasting:
Females present at birth with ambiguous genitalia

Males present at 1-2 weeks with failure to thrive, dehydration, hyperkalemia, hyponatremia

Front 50

68 year-old female
Rash involving a single dermatome on chest

Diagnosis
Symptom likely to suffer from within 6 months?

Back 50

Herpes Zoster--arises when latent varicella zoster virus reactivated within a single dorsal root sensory ganglion

Rash does not usually recur in immunocompetent host.

Post-herpetic neuralgia is most common complication --described as stabbing, localized pain that lasts for several months.

Front 51

Why do oral contraceptives reduce the risk of non-hereditary ovarian cancer?

Back 51

Risk of ovarian cancer is associated with irregularities of reparative processes of ovarian surface (repeated aberrant repair is thought to induce dysplasia and neoplasia).

OCPs reduce the risk of non-hereditary ovarian cancer by decreasing the total number of times a woman ovulates in her lifetime.

With fewer ovulatory cycles, there is less need for repair at the ovarian surface.

Front 52

What can decrease the risk of ovarian cancer?

Back 52

Multiparity
Breast-feeding
OCPs

Front 53

Warfarin-induced skin necrosis:
Pathophys

Back 53

Protein C and S are natural anticoagulants.

Following warfarin administration, there's a rapid drop in Factor VII and Protein C.

If protein C deficiency present, procoagulant/anticoagulant imbalance is exaggerated, causing hypercoagulable state with thrombotic occlusion of microvasculature and skin necrosis.

Front 54

3-month old male
Right-sided white pupillary reflex

Diagnosis

Back 54

Retinoblastoma

Front 55

Sporadic vs Familial Retinoblastoma:
Prognostic differences

Back 55

Sporadic: unlikely to develop other malignancies

Familial: most likely to develop osteosarcomas (or other sarcoma, but mostly osteosarcoma)

Front 56

What proteins are able to directly bind DNA?

Back 56

Transcription Factors
Steroids
Thyroid Proteins
Vitamin D Receptors
Retinoic Acid Receptors
DNA transcription and replication proteins

Front 57

N-myc:
Role

Back 57

Transcription factor--CAPABLE OF BINDING DNA

Front 58

First line treatment of hypertriglyceridemia.

Back 58

Fibrates

Front 59

22 year-old male
Serum triglyceride of 1500 mg/dL (normal <200)

Treatment?

Back 59

Niacin and fibrate (ex:gemfibrozil)

Front 60

Ezetimibe:
MOA

Back 60

Selectively inhibits intestinal absorption of cholesterol.

Front 61

What is projection?

Back 61

Transplanting unacceptable impulses or affect onto another person or situation.

Ex: When MD hears of patient's drug abuse, he transplants unacceptable impulses towards his daughter on the patient's mother (bc she does drugs too apparently).