Endocrine Abstracts

Hypoglycaemia is often referred to Endocrinology for investigation and management. Occasionally, these referrals are in the context of malignancy and we seek to exclude ectopic insulin secretion, as well as other causes. This case highlights a less recognised cause for hypoglycaemia in haematological malignancy. The patient, a 78 year-old man with advanced Mantle Cell Lymphoma presented with hypoglycaemia and was admitted under Haematology, who had been treating with chemotherapy. Alongside profound hypoglycaemia (glucose), his biochemistry showed significant lactataemia (18 mmol/l). He was treated with intravenous Dextrose and, whilst euglycaemic, remained asymptomatic and well. The patient had Type 2 diabetes and was treated with Metformin, however his biochemical derangement persisted despite discontinuing this. Investigations excluded insulin hypersecretion as a cause; Addison’s disease (cortisol >350 nmol/l), acute liver failure (no other features), tumour lysis syndrome (urate normal) and rapid tumour progression (assessed via CT scan) were also excluded. Of note, both his glucose and lactate levels normalised following further chemotherapy implying a correlation between the tumour load and the biochemistry. The patient remained intermittently dependent upon IV dextrose until his eventual death. It has been hypothesised that anaerobic metabolism of glucose by the highly metabolically active tumour cells resulted in both hypoglycaemia and markedly elevated lactate levels. There is some evidence in the literature to support this as similar presentations have been reported in the past. This case provides a presumed further example and may encourage others to consider this process as a differential in patients with haematological malignancy, significant tumour load, hypoglycaemia and lactic acidosis.