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

Abstract

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. 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 …