Lipids detected by brain MRS during coma caused by carnitine palmitoyltransferase 1 deficiency

Prolonged coma without hypoglycemia or hyperammonemia is a diagnostic challenge. We report brain proton MR spectroscopy (¹H MRS) findings in an infant with unexplained coma as the first manifestation of carnitine palmitoyltransferase (CPT) 1 deficiency.

Case report.

An 11-month-old girl became pale and floppy after an 11-hour fast. On admission, she was somnolent but could be awakened. The liver was 2 cm below the right costal margin. She had metabolic acidosis (pH 7.28, Pco₂ 4.7, base excess −5.8, Hco₃ 19) and slightly elevated alanine aminotransferase (ALT) 46 U/L (normal <40 U/L). Blood glucose and lactate, plasma ammonia, CSF analysis, and brain 1.5 T MRI were normal.

Despite IV glucose infusion (3 to 4 g/kg/day), her consciousness fluctuated from wakefulness to a sleep-like state, which deepened to coma. On day 6, brain MRI was again normal, whereas ¹H MRS (figure) revealed a very high N-acetyl aspartate (NAA)/choline (Cho) ratio for age, excess of glutamate/glutamine, and large lipid peaks in the thalamus, white matter, and cortex.¹ EEG showed background slowing with high delta waves without epileptiformic activity. Plasma ammonia fluctuated from 155 to 60 to 102 μmol/L (normal <50 μmol/L) and ALT increased to 160 U/L. She became icteric …