Index of Suspicion

Case 1 Presentation

A 28-month-old boy is admitted to the hospital having decreased appetite, vomiting, rapid breathing, and lethargy. Although he has only mild respiratory symptoms, he is breathing rapidly.

On physical examination, the child is lethargic and breathing at a rate of 56 breaths/min. There is no fever. He does not appear dysmorphic. His weight is at the 10th percentile, height at the 5th percentile, and head circumference at the 25th percentile. The remaining physical findings, including those on pulmonary evaluation, are normal.

His admission blood gas values are: pH, 7.03; P𝒸ℴ₂, 12 torr; and base excess −26 mEq/L (normal, ±2 mEq/L). Blood chemistry findings are as follows: sodium, 137 mEq/L (137 mmol/L); chloride, 109 mEq/L (109 mmol/L); potassium. 4.2 mEq/L (4.2 mmol/L); bicarbonate, <5 mEq/L (5 mmol/L); blood urea nitrogen, 24 mg/dL (8.6 mmol/L); creatinine, 0.6 mg/dL (53 mcmol/L); anion gap, 23 (normal, 8 to 16); lactate, 0.7 mg/dL (0.08 mmol/L); aspartate aminotransferase, 42 U/L; alanine aminotransferase, 8 U/L; total bilirubin, 0.6 mg/dL (10.3 mcmol/L); and ammonia, 40 mcmol/L (normal, 9 to 33 mcmol/L). His blood acetone is positive at a dilution of 1:32.

The child’s blood glucose is 297 mg/dL (16.5 mmol/L); he had received glucose intravenously in the ambulance. Findings on urinalysis include: pH, 5.5; specific gravity, 1.025; ketones 3+; glucose 2+; and reducing substances, present. Blood ethanol and salicylate levels are normal. His white blood cell count is 18×10³/mcL (18×10⁹/L), and his hemoglobin is 12.5 g/dL (125 g/L).

The child improves after intravenous therapy and is discharged. He is readmitted 2 weeks later with a similar presentation and again responds to intravenous fluid treatment. Detailed evaluation leads to a diagnosis.

Case 2 Presentation

A 29-month-old boy from eastern North Carolina is admitted to the hospital in September having acute mental status changes. For the past …