Plasma carnitine deficiency. Clinical observations in 51 pediatric patients
S. C. Winter, S. Szabo-Aczel, C. J. Curry, H. T. Hutchinson, R. Hogue and A. Shug
We studied the clinical spectrum associated with secondary plasma carnitine
deficiency in 51 pediatric patients. Forty-three patients had total plasma
carnitine values below 20 mumol/L and an additional eight patients had
total values above 20 mumol/L but had low free plasma carnitine levels. The
clinical presentation in the patients with total plasma carnitine
deficiency included hypotonia (34 of 43), failure to thrive (27 of 43),
recurrent infections (27 of 43), encephalopathy (six of 43), nonketotic
hypoglycemia (seven of 43), and cardiomyopathy (nine of 43). Of the eight
patients with low free and elevated esterified carnitine levels, the signs
and symptoms at presentation included hypotonia (six of eight), recurrent
infections (six of eight), failure to thrive (six of eight), encephalopathy
(three of eight), nonketotic hypoglycemia (one of eight), and
cardiomyopathy (one of eight). All patients were treated with L-carnitine.
Treatment time varied from one month to 24 months (average, four months). A
subjective improvement in muscle tone was seen in 24 of 38 patients, 22 of
33 patients showed acceleration of incremental growth, and infection
frequency appeared to decrease in 18 of 33 patients. After therapy, the
echocardiograms of all patients with cardiomyopathy normalized. There were
no further hypoglycemic episodes. Of the nine patients with encephalopathy,
eight showed improvement in their mental status. Three patients died of
complications of their primary disorder. In our experience, secondary
plasma carnitine deficiency is a common pediatric finding. The presence of
failure to thrive, recurrent infections, hypotonia, encephalopathy,
cardiomyopathy, or nonketotic hypoglycemia requires investigation of
carnitine status.
