Congenital hyperinsulinism: review of 12 Tunisian cases

Congenital hyperinsulinism in infancy (CHI) is a heterogeneous disorder with respect to genetics and response to therapy. Data on CHI are sporadic in North African population.

To characterize the clinical features and outcome of 12 Tunisian patients with CHI.

data of patients diagnosed with CHI during the period 1989-2007 were retrospectively analyzed. Diagnosis was considered whenever hyperinsulinemia ≥ 10μ UI/ml was concomitant to hypoglycemia < 3mmol/l and/or high insulin to glucose ratio > 0.3 and/or positif glucagon test. Transient causes of hypoglycemia, adrenal and growth hormone deficiency were excluded.

There were nine infants diagnosed at a median age of 17 months and three newborns. Permanent hyperammoniemia, found in one patient, guided to leucine-sensitive hyperinsulinism. Seven patients presented with seizures, two with psychomotor delay and one with recurrent malaises. Among 42 assays of plasmatic insulin, when in hypoglycemia, 40% only were ≥ 10μU/ml. Three patients resisted to diazoxide and underwent subtotal pancreatectomy complicated by diabetes mellitus in two cases and persistent hypoglycemia in one patient. Histological examination concluded to diffuse hyperplasia of pancreatic cells. Diazoxide was discontinued in four out the eight responders' patients. Four patients died, seven patients developed variable degrees of mental retardation and five suffered from epilepsy.

Early onset forms were, as reported in the literature, mostly resistant to medical therapy. The high proportion of neurological sequelae is related to diagnosis delay or to a late surgery. We focus on the importance of a precocious diagnosis and aggressive treatment of hypoglycemia.