ESPE Abstracts

Background: Congenital hyperinsulinaemic hypoglycaemia (CHI) can cause various degrees of hypoglycaemia in infancy. In mild CHI, unnoticeable recurrent hypoglycaemia may cause deterioration of central neurological functions in patients. We report a case of mild CHI that presented with developmental delay without any previous hypoglycaemic events.

Case presentation: An 18-month-old Japanese girl was admitted to our hospital with seizures and unconsciousness. Her blood glucose level measured at admission was 58 mg/dl. However, laboratory data collected the next day showed a blood glucose level of 40 mg/dl and a serum insulin level of 10.9 μU/ml. On the basis of these findings we made a diagnosis of CHI. The patient had never shown apparent hypoglycaemic events previously and had developed normally until 6 months of age, after which mild developmental delay was observed. She was administered diazoxide that was followed by severe neutropenia. A bone marrow aspiration performed 2 days after cessation of the drug showed a reduction in nucleated cell count and increased numbers of immature myeloid cells, indicating transient myeloid suppression. Because we were unable to control her blood glucose levels appropriately by meals or other supplemental diets, and octoreotide is not registered for treatment CHI in Japan, she was restarted on diazoxide with close monitoring. The patient has not developed neutropenia again and her metabolic status has been controlled successfully.

Conclusion: In patients who develop gradual central neurological problems, recurrent blood glucose measurements should be recommended for the differential diagnosis of CHI. Neutropenia is a rare adverse effect of diazoxide. However, this may be transient and the drug should be reintroduced with close monitoring after recovery of the bone marrow.