Endocrine Abstracts

Introduction: Secondary causes of diabetes refer to a category in which diabetes is associated with other diseases. They are thought to constitute less than 2% of the total cases of diabetes.

Case report: A 56 year-old caucasian man, with no relevant medical history, presented to the Emergency Department with fatigue, polyuria, polydipsia, polyphagia and involuntary weight loss (6 kg in two weeks). He was hemodynamically stable and exhibited a glycaemia of 445 mg/dl without acidosis. Insulin perfusion was initiated and the patient was hospitalized with the diagnosis of new-onset diabetes. Physical examination revealed a greyish skin tone, body mass index of 19 kg/m² and hepatomegaly. Blood analysis showed a haemoglobin A1c of 13.4%, negative anti-GAD and anti-insulin antibodies, transferrin saturation of 98% and high ferritin levels (4533 ng/ml). This clinical picture raised the suspicion of diabetes secondary to hemochromatosis. Abdominal ultrasound showed an enlarged liver (19.5 cm) with bright echostructure and the hepatic magnetic resonance imaging described signs of iron overload. Liver biopsy was then performed showing accentuated iron deposits in the hepatocytes, sinusoidal lining cells and bile ducts epithelia. Genetic study identified a HFE gene mutation (C282Y homozygote). Due to possible iron accumulation in the pituitary gland and the patient complaints of erectile dysfunction, pituitary function was evaluated revealing hypogonadotropic hypogonadism (total testosterone 0.59 ng/ml; FSH 3.40 mUI/ml; LH 2.78 mUI/ml) with no other axis affected. Patient was discharged from hospital with a basal-bolus insulin regimen and a 250 mg testosterone monthly enanthate injection. He maintains follow-up with an A1c of 7.3% and undergoing periodic phlebotomies.

Conclusions: In hemochromatosis iron accumulation in the skin and pancreas can lead to hyperpigmentation and impair insulin production causing the so called ‘bronze diabetes’. This case alerts clinicians not to overlook secondary causes of diabetes that can be precociously suspected based on a careful physical examination.