Medical Mystery of the Week

You are sent a picture of the face and a microscopic picture of the urine of a 3-year-old previously healthy child. What is your diagnosis, what test(s) would you order to confirm your suspicions, and what treatment, if any, do you advise? What symptoms and signs do you think the child has?

DIAGNOSIS: Impetigo complicated by post-streptococal glomerulonephritis.

Impetigo is a cutaneous/mucus membrane infection due to group A streptococci and/or Staphylococcus aureus. Most common in children, the lesions are typically "honeycrusted" and pustular or bullous. A microscopic examination of a urine sample from this child revealed dysmorphic red blood cells (see right side inset) which are diagnostic of glomerulonepritis - in this case post-steptococcal. Nephritogenic glomerulonephritis typical occurs after streptocvoccal skin infection in contrast to rheumatic fever which is a complication of group A streptococcal pharyngitis. Antibiotic selection should be based on in vitro sensitivity testing.