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NBME 20 Answers

nbme20/Block 4/Question#46

A 28-year-old woman at 32 weeks' gestation comes to ...

Obstructive uropathy

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 +7  upvote downvote
submitted by xxabi(55),

Also for those of you who are totally clueless like me, urinary tract obstruction = obstructive uropathy.


 +2  upvote downvote
submitted by sympathetikey(133),

Hydronephrosis

Distention/dilation of renal pelvis and calyces A . Usually caused by urinary tract obstruction (eg, renal stones, severe BPH, congenital obstructions, cervical cancer, injury to ureter, pregnancy apparently); other causes include retroperitoneal fibrosis, vesicoureteral reflux. Dilation occurs proximal to site of pathology. Serum creatinine becomes elevated if obstruction is bilateral or if patient has an obstructed solitary kidney. Leads to compression and possible atrophy of renal cortex and medulla.


 +0  upvote downvote
submitted by neonem(138),

Obstructive uropathy causes a postrenal azotemia --> when prolonged, tubular damage ensues. This leads to an acute tubular necrosis, characterized by necrotic plugs in the tubular system as seen in the image

meningitis  Does anyone know the relevance of the stem saying: "during this time she also has been crying frequently"? +2  
usmleuser007  Think the postrenal azotemia is d/t her pregnancy. With the increasing in size fetus, the pelvic cavity is being compressed and thus there is pressure on the ureters. This leading to the presentation. As per above --- the crying maybe just d/t her pain and emotional stress caused by worrying about possible complications regarding her fetus. +1  

 +0  upvote downvote
submitted by laminin(3),

also maybe could do process of elimination...the 'costophrenic angle tenderness' clues us in to it being a renal problem, and the only renal answer choice is obstructive uropathy


 +0  upvote downvote
submitted by redvelvet(1),

costophrenic angle tenderness and fever WBC casts in tubules on that photo for example All of them is leading us to pyelonephritis. And even minor cystitis can cause pyelonephritis in pregnancy due to obstructive uropathy.