Make the Diagnosis: Summer 2013

An 8-year-old male with a history of bilateral ptosis and narrow external auditory canals presented to his pediatrician with a 5-month history of decreased appetite and weight loss. He also complained of fatigue, polyuria, and polydipsia. He was on no medications, and there was no significant family history. One year prior, his weight and height were at the 10th percentile for age. On presentation, his weight and height had both fallen below the 5th percentile. He had normal blood pressure. Urinalysis had a specific gravity of 1.005 with no blood, protein, or glucose. Metabolic panel was significant for sodium 142 mmol/L, potassium 3.9 mmol/L, chloride 102 mmol/L, bicarbonate 21 mmol/L, BUN 94 mg/dL, creatinine 5.4 mg/dL, calcium 7.9 mg/dL, and phosphorous 8.2 mg/dL. Additional labs included hemoglobin 7.4 g/dL with normal mean corpuscular volume and parathyroid hormone level 1289 pg/mL. Renal ultrasound showed normal size kidneys with increased echogenicity bilaterally.

No one correctly guessed last issue’s Make the Diagnosis answer. The correct diagnosis is neuromyelitis optica (NMO), the topic of this issue’s cover story.