UWorld Test 5/25/2014

Question 1

Enthesopathies (inflammation at site of tendon insertion) are common in what MSK condition?

Answer 1

Ankylosing spondylitis. Involvement of costovertebral and costosternal junctions may cause limitations of chest movements and cause hypoventilation. Check for chest expansion

Question 2

Vitaminc C deficiency found in?

Answer 2

Alcoholics, homeless, drug users

Question 3

Vitamic C is responsible for?

Answer 3

Hydroxylation of specific proline and lysine residues.

Question 4

Scopolamine?

Answer 4

Muscarinic antagonist.. Won’t work at nicotinic receptor sites. May be used to ameliorate effects of excessive AchE inhibitors given for Myasthenia gravis

Question 5

Propionic acidemia is a result of what congenital deficiency?

Answer 5

Deficiency of propionly coA carboxylase which converts propionyl CoA to methylmalonyl CoA.

Question 6

Propionyl CoA is derived from?

Answer 6

Isoleucine, threonine, methionine, valine, odd no FA and cholesterol side chains.

Question 7

Selective IgA deficiency is a/w

Answer 7

Anaphylactic response to transfused blood products due to immune response against transfused IgA which is perceived to be foreign. Also get recurrent sinopulmonary and GI infections

Question 8

Blanching of a vein into which NE is injected into with induration and pallor of tissues surrounding IV injection site is a sign of?

Answer 8

NE extravasation and vasoconstriction can lead to local tissue necrosis.. Give an alpha 1 blocker, like phentolamine (this is actually a reversible general alpha blocker) to reverse effects and cause vasodilation

Question 9

What is isolated systolic hypertension? When does it occur and why?

Answer 9

When systolic is high (above 140) but diastolic is normal (Below 90). Due to aortic stiffening (decrease in compliance). Age related. Found commonly in people over 50

Question 10

Gamma-glutamyl transpeptidiase (GGT) specific to?

Answer 10

Liver and biliary epithelia

Question 11

What do these following viruses bind to? 1) CMV 2) EBV 3) HIV 4) Rabies 5) Rhinovirus

Answer 11

1) cellular integrins 2) CD21 3) CD4, CXCR4, CCR5 4) Nicotinich Ach R 5) ICAM-1 (CD54)

Question 12

Beta-thalassemia is caused by defect in?

Answer 12

Defective transcription, processing and translation of beta globin mRNA causing aberrant splicing of pre-mRNA or premature chain termination

Question 13

What is pyridoxine?

Answer 13

Vitamin B6

Question 14

How do patients with homocystinuria present? What are they at risk for?

Answer 14

Lens subluxation/ectopia lentis (dislocated lens), marfinoid habitus (long limbs, arachnodactyly), osteporosis. High risk for thromboembolic episodes involving large and small vessel especially in brain heart and kidney

Question 15

Most common cause of homocystinuria

Answer 15

deficiency of cystathione synthetase, requires Vit B6 (pyridoxine). Treat with Vit B6, 50% of patients respond well

Question 16

Lipid is digested and absorbed in which part of the GI tract?

Answer 16

Digested in duodenum, absorbed in jejunum

Question 17

Signs of foot drop and inability to evert the foot is damage to which nerve?

Answer 17

Common peroneal. Often injured with injury to head of the fibula.

Question 18

What are the side effects of lithium? What should be monitored?

Answer 18

LMNOP - movement (tremor), neprhogenic diabetes, hyOthryoidism, pregnancy problem (ebstein’s analmoly), sedation. Monitor TSH, renal function

Question 19

Portovacal anastomses for 1) eosphageal varices 2) caput medusae 3) hemorrhaids

Answer 19

1) portal: left gastric // systemic: esophageal 2) portal:paraumbilical // systemic: superficial and inferior epigastric 3) portal: superior rectal // systemic: inferior and middle rectal

Question 20

What is cromolyn? MOA?

Answer 20

Cromolyn used to treat allergic rhinitis and bronchial asthma (Second line). Prevents mast cell degranulation and release of chemical mediators.

Question 21

Abrupt onset of gross hematuria and proteinuria w/ hx of sickle cell disease suggestive of?

Answer 21

Renal papillary necrosis.

Question 22

Renal papillary necrosis is a/w?

Answer 22

Sickle cell, diabetes, acute pyelonephritis, chronic phenacetin use (acetaminophin is a derivative of phenacetin)

Question 23

What happens to the spleen in sickle cell disease by adulthood?

Answer 23

Sickle cell disease : vaso-occlusions cause infarction of various tissues. Repeated splenic infarctions are common leads to significant scarring, fibrosis, and atrophy of spleen. => autosplenectomy.

Question 24

Patients with chronic hemolytic disease like SS are predisposed to what kind of deficiency?

Answer 24

Folic acid deficiency due to increased cell turnover, leading to a megaloblastic, macrocytic anemia.

Question 25

What is biliary sludge? What condition predisposes to the formation fot his?

Answer 25

Gallbladder hypomotility => bile precipitation and biliary sludge formation. Precursor to stone formation. Acute cholecystitis occurs in 20% of ppl with gallbladder hypomotility.

Question 26

Acute transplant rejection occurs when? What kind of process is it? What are the features?

Answer 26

Occurs within weeks to months. Can be T cell or B cell mediated. Features are vasculitis with lymphocytic inflitrate. Prevent/reverse with immunosuppressant.

Question 27

What is effect modification?

Answer 27

When the effect of a main exposure on an outcome is modified by another variable.

Question 28

What is Winter’s formula and when is it used?’

Answer 28

Pa CO2 = (1.5*bicarbonate) +8 +/- 2. Used to evaluate respiratory compensation in the setting of metabolic acidosis. If PaCO2 is not within this range = respiratory failure

Question 29

Niacin 1) Effect on LDL 2) Effect on HDL 3) Effect on TAGS. // MOA // Side effects?

Answer 29

1) Decrease (2 arrows) 2) Increase (2 arrows) 3) Decrease (1 area)….MOA: Inhibits lipolysis in adiopose tissue; reduce hepatic VLDL synthesis. Side effects: VASODILATION, red, flushed face. Potentiates some anti-hypertensives like like vasodilators, INCREASES INSULIN RESISTANCE causing hyperglycemia/acanthosis nigracans, INCREASED SERUM URIC ACID

Question 30

Acute effects of glucocorticoids on CBC

Answer 30

Neutrophilia (due to demargination of neutrophils previously attached to vessel wall), decreased lymphocyte, monocyte, basophil, and eosinophil counts

Question 31

What is attributable risk?

Answer 31

Risk attributable to a risk factor in an exposed population. (RR-1)/RR

Question 32

How is left ventricular failure related to lung compliance

Answer 32

Left ventricular failure => decreased cardiac output, increased end systolic pressure in heart chambers => impairs diastolic return to left side of heart => increased pulmonary vein pressure => causes edema => decreased lung compliance (inability to stretch lungs during inhalation)

Question 33

How does lactase deficiency effect stool ph

Answer 33

Lactase deficiency => unabsorbed lactose => broken down by bacterial fermentation=> produces short chain FA and hydrogen => decreases stool pH

Question 34

Know instrince kinase receptor mechanism (same for insulin). What causes insulin resistance?

Answer 34

Growth factor/Insulin binds => autophosphyrolation of intrinsic tyrosine kinase => phosphorylates IRS-1/2 => 1) activaites PI3K which converts PIP2 to PIP3 => translocation of GLUT4 to membrane and intake of glucose 2) activates RAS-GDP to RAS-GTP => activates MAPKK/MEK pathways => cell growth, dna synthesis etc. ABERRANT serine or threonine phsophylration will increase resistance to insulin. Catecholamines, glucocorticoides, TNF-alpha mediate resistance this way

Question 35

Midshaft fracture of the humerus causes injury to what structures

Answer 35

Deep brachial artery and radial nerve

Question 36

Diabetic neuropathy usually causes what kind of damage to CN3? Sx?

Answer 36

ischemic = affects central running somatic fibers. Ptosis and down and out gaze

Question 37

Dystrophic calficiation is a hallmark of?

Answer 37

Preceding cell injury and necrosis. Occurs in all kinds of necrosis including fat necrosis

Question 38

What tests can help determine failed fusion of neuropores (4th week) - neural tube defect

Answer 38

Increased AFP in amniotic fluid and maternal serum. Increased acetylcholinesterase in amniotic fluid is helpful confirmatory test (fetal AchE transudates across defect into the amniotic fluid)

Question 39

What is differential cyanosis? What kind of congential heart defect can this occur in?

Answer 39

Cyanosis of lower extremities but not of the upper extremities. Occurs when there is reduced arterial oxygen saturation in the distal aorta compared to proximal aorta. Happens in PDA. Early in life, shunt is left to right but increased PAH then reverses this and makes it right to left causing differential cyanosis

Question 40

Digoxin is cleared by? What consideration must be accounted for when dosing it for elderly?

Answer 40

Digoxin cleared by kidney. 1.5 day half life. There is age related diminised renal function as you get older WITHOUT a concomitant rise in serum creatinine because as you get older you also decrease muscle mass. Therefore, need to adjust dosing for elderly.

Question 41

What are the side effects for digoxin?

Answer 41

Cholinergic - anorexia, n/v/d, blurry vision (van gogh)

Question 42

Methotrexate? MOA? Uses? Toxicities?

Answer 42

Folic acid analog, Inhibits DHFR => reduced dTMP, DNA and protein synthesis. USES: leukemias, lymphomas, choriocarcinomas // RA, IBD, psoriasis, ectopic pregnancy, abortion. TOXICITY- myelosupression, rescute with leucovorin, hepatotoxic (causes macrovesicular fatty change in the liver), mucositis (stomatitis - painful mouth ulcers), teratogenic

Question 43

How does thryoid hormone affect the nervous system?

Answer 43

Thyroid hormone increased beta 1 receptor sensitivity= increases CO, SV, HR, contractility

Question 44

Effect of beta blockers on thyroid metabolism

Answer 44

Decreases adrenergic stimulation and also decreases peripheral conversation of T4 to T3

Question 45

MOA of Raltegravir

Answer 45

Inhibits HIV DNA integration into host chromosom by reversibly inhibiting HIV integrase. Tox: Hypercholesterolemia

Question 46

What is claudication

Answer 46

Intermitten muscle pain produced by exercise and relieved by rest. Almost aways the result of atherosclerosis of larger arteries. These are due to lipid filled intimal plaques that make the vessels stenotic.

Question 47

Monosomy as in the case of Turner’s (45X,O) is due to what kind of error

Answer 47

Etiology is loss of parental X chromosome during mitosis

Question 48

What is Fabry disease?

Answer 48

Lysosomal storage disease. X linked recessive. Deficiency in alpha-galactosidase A. Leads to accumulation of ceramid trihexoside. PPT: peripheral neuropathy, angiokeratomas. Leads to progressive cardiovascular, renal disease

Question 49

What is amlodipine? Greatest effect exerted on? Toxicity?

Answer 49

Dihydropyridine voltage gated Ca+ channel blocker. Greatest effect on vascular smooth muscle (as opposed to cardiac muscle). Side effects: Flushing and peripheral edema.