Renal & Electrolytes

Question 1

Drugs that cause sxs of urinary retention

Answer 1

TCA’s, Antipsychotics, antihistamines & sympathomimetics (secondary to cholinergic blockage, which inhibits detrusor muscle contraction)

Question 2

Causes of postrenal failure

Answer 2

BPH, Prostate cancer, bladder tumors, and urinary retention (2/2 neurogenic bladder, anticholinergic, or sympathomimetic drugs). NB: Unless present bilaterally renal stones rarely lead to obstructive kidney failure

Question 3

Diagnosis of Obstructive RF

Answer 3

Detection of hydronephrosis on U/S.

Question 4

Toxins that lead to ATN

Answer 4

Cisplastin, aminoglycoside, amphotericin B, IV contrast, myoglobin

Question 5

Ischemic ATN vs. Prerenal azotemia

Answer 5

Ischemic ATN presents with muddy brown cast + FENa>2%. Prerenal azotemia has no muddy brown cast and FENa is<1%, BUN/Cr ratio is >20