UWorld-Renal

Question 1

A hypertensive patient now has a serum calcium of 11mg/dL. Explain how this might occur.

Answer 1

hydrochlorothiazide is the commonest diuretic and it causes increased distal reabsorption of calcium leading to hypercalcemia

Question 2

why might a blood transfusion cause hypocalcemia

Answer 2

citrate, a component in packed red blood cell infusions, can chelate calcium and magnesium

Question 3

in a patient with high pH and high PCO2 what serum lab value would be most informative in determining the diagnosis

Answer 3

chloride; in a patient with metabolic alkalosis you’d want to check chloride levels to determine if it is due to vomiting (loss of H+), contraction alkalosis (urinary excretion of Na and Cl) or Conn syndrome (hyperaldosteronism leading to overactivity of NaATPase and NaH exchanger)

Question 4

explain the sodium cyanide-nitroprusside test and what diagnosis it confirms

Answer 4

cyanide added to the urine sulfates cystine to create cysteine; nitroprusside is then added which binds the cysteine generating a red-purple color;
confirms diagnosis of cystine nephrolithiasis

Question 5

a female with fully developed, normal genitalia and amenorrhea who is otherwise healthy likely has…

Answer 5

eugonadal amenorrhea is evidenced by normal secondary sex characteristics; the cause of the amenorrhea is likely anatomical (i.e. Mullerian agenesis or imperforate hymen/ hematocolpos)

Question 6

a woman with Lupus and high PTT likely has what associated condition and is at risk for what complications

Answer 6

lupus anticoagulant (anti-phospholipid antibodies that render the patient hypercoagulable and predispose to recurrent thromboemboli and miscarriages)

Question 7

which two cells mediate type 1 hypersensitivity reactions

Answer 7

mast cells and basophils; NOT EOSINOPHILS (eosinophils bind Fc region of IgE bound to parasite antigen and attack via antibody-dependent cellular cytotoxicity)

Question 8

what are the two segments of the posterior urethra and which is more susceptible to injury (i.e. due to pelvic trauma)

Answer 8

posterior urethra consists of prostatic urethra and bulbous urethra;
the bulbous urethra is vulnerable to injury due to lack of surrounding protective structures

Question 9

what pathogen causes granuloma inguinale;

characteristic histology

Answer 9

Klebsiella granulomatis (sexually transmitted);
on histology:  gram negative rods with Donovan bodies (rod-shaped intracytoplasmic inclusions)

Question 10

condyloma lata vs. condyloma acuminata

Answer 10

condyloma lata is seen in secondary syphillis;

condyloma acuminata results from HPV 6 or 11 (they have low oncogenic potential)

Question 11

what key finding differentiates endometriosis and adenomyosis

Answer 11

uterine size: both present with metrorrhagia, dysmenorrhea and or abdominal pain, but adenomyosis presents with enlargement of the uterus while endometriosis is associated with normal sized uterus

Question 12

presentation of Kleinfelter’s vs. presentation of anabolic steroid supplementation

Answer 12

both can present with testicular shrinkage, but Kleinfelter’s will also present with tall stature, firm testes (due to atrophic hyalinization) and gynecomastia

Question 13

what lab can help confirm suspicion of Kleinfelter’s?

why?

Answer 13

high FSH;
dysgenesis of seminiferous tubules in Kleinfelter’s results in decreased inhibin ==> increased FSH
(note: there is also Leydig cell dysfunction leading to decreased T and increased LH, but these levels are much more variable and therefore less reliable)