Massive hepatomegaly, steatosis, and secondary plasma carnitine deficiency in an infant with cystic fibrosis.

Hepatomegaly and steatosis are common findings in children with cystic fibrosis and are most often attributed to malnutrition. An infant fed a carnitine-free soy formula is described. Massive hepatomegaly and steatosis developed in the baby at a time of severe viral respiratory illness, prolonged fasting, hypoglycemia, and hypoketonuria. The infant was found to have secondary plasma carnitine deficiency and excessive loss of carnitine in the urine as part of a more generalized renal tubular dysfunction accompanying vitamin D deficiency and secondary hyperparathyroidism. With correction of the metabolic abnormalities and institution of a high carnitine diet, the hepatomegaly disappeared, plasma carnitine returned to normal levels, and the renal carnitine loss ceased. The findings suggest that secondary carnitine deficiency may play a role in fatty infiltration of the liver in patients with cystic fibrosis, especially during times of severe fasting stress.