Endocrine Abstracts

We present a 52-year-old lady with type 2 diabetes mellitus, referred by her GP with poor glycaemic control. Her past medical history included haemochromatosis, undifferentiated connective tissue disorder, depression, hypothyroidism, pernicious anaemia and alcohol abuse. Relevant medications were metformin 1 g bd, novorapid 28 units tds, levemir 30 mg od and prednisolone 5 mg od. Her HbA1c was 8.1%, renal function and baseline pituitary function was normal. Following an admission with unexplained hypoglycaemia, her diabetic medications were stopped. An abdominal ultrasound reported a fatty liver, enlarged spleen and limited view of the pancreas.

On follow-up, she had an episode of witnessed hypoglycaemia. Serum glucose, C-peptide, insulin and pro-insulin were sent. She denied exogenous administration of insulin/ oral hypoglycaemic agents (OHAs). A month later she had symptomatic hyperglycaemia and metformin was commenced. Three weeks following that, she was found unconscious with a GCS of 3, profoundly hypoglycaemic (venous glucose 0.8 mmol/l) and hypertensive (BP 160/100). CT brain showed basal ganglia changes in keeping with haemochromatosis. Renal function, liver enzymes, electrolytes and paracetamol/salicylate levels were normal. TFTs suggested probable noncompliance with thyroxine. Full blood count revealed macrocytosis. There was no evidence of insulin/OHAs overdose from collateral history. She did not make any neurological recovery and subsequently died 2 weeks after admission.

Initial results from witnessed hypoglycaemia:

Glucose 2.6 mmol/l

C-peptide 381 pmol/l (0–480)

Insulin 91.6 mU/l (0–10)

Disproportionately high insulin to C-peptide suggests probable exogenous insulin use given that additional history revealed possible Munchausen’s syndrome with deliberate overdose of azathioprine resulting in neutropenic sepsis.

However, pro-insulin measured 52 pmol/l (<10) which is significantly elevated. This raises the possibility of an insulinoma or sulphonylurea overdose. Postmortem identified a pale area in the pancreas and a small well-circumscribed lung lesion. Histology is pending.