(BMJ) - A 35-yo man complained of multiple boils in his perianal region that were unresponsive to repeated I & D and antibiotics over 4 yrs. Exam revealed fistula-in-ano w/ multiple external openings. The cause was confirmed on histopathologic exam. What is it?
Tuberculosis
Anal carcinoma
Crohn disease
Syphilis
Gonorrhea
You are correct. Tuberculosis was confirmed on histopathologic exam of one of the tracts. A fistula-in-ano w/ multiple openings is typical of ano-rectal tuberculosis, for which the diagnosis is often delayed. The pt responded well to antitubercular tx.
(BMJ) - A 46-yo African American man w/ uncontrolled DM and HTN presented w/ SOB and confusion. Exam: white, powdery deposits on face and limbs. Labs: BUN=100 mg/dL, Cr=7.3 mg/dL. The skin findings resolved after 10 days of hemodialysis. What caused the powdery substance?
Crystallized urea
Nephrogenic fibrosing dermopathy
Calcinosis cutis
Calciphylaxis
Xerosis
You are correct. Crystallized urea, otherwise known as "uremic frost,” can be seen in patients w/ renal failure. It occurs as a consequence of elevated levels of urea in sweat that precipitates and crystallizes on skin surfaces.