Endocrine Abstracts

Introduction: Cranial diabetes insipidus (DI) is a rare presenting complication of acute myeloid leukaemia (AML) or myelodysplasia, usually associated with complex cytogenetics. We report the case of a patient previously treated with cytotoxic therapy who presented with DI and AML. Case report: A 39 year old male presented with a three month history of lethargy, fatigue, and breathlessness. He also reported a ten day history of acute onset polydipsia and polyuria. He had been previously been treated with Etoposide and Carboplatin for a seminoma. On admission, he was anaemic, with Hb of 9 g/dl, and thrombocytopenic with a platelet count of 41×109/L. Bone marrow biopsy revealed a hypercellular marrow with over 30% myeloid blast cells, confirming a diagnosis of AML. Cytogenetics showed a complex karyotype, typical of the secondary leukaemia associated with previous cytotoxic therapy. His electrolytes were normal (serum sodium 139 mmol/L), as were a serum calcium and fasting glucose. Anterior pituitary function tests were normal. Plasma and urine osmolalities were 306 mM/kg and 158 mM/kg respectively. A water deprivation test was consistent with a diagnosis of partial central diabetes insipidus. MRI brain and pituitary showed slight stalk thickening but no other pathology. The patient’s symptoms improved with Desmopressin and he is currently undergoing chemotherapy for AML.

Discussion: The presentation of diabetes insipidus with acute myeloid leukaemia is a rare but recognised association. The mechanism of DI in AML is unclear but may be due to direct infiltration, infection, thrombosis or haemorrhage. The overall survival outcomes of these patients are poor. As in this case, the association of DI and AML is mainly seen in patients with myelodysplasia (pre-leukaemia) and complex cytogenetics, suggesting a relationship between myelodysplastic syndrome and the development of DI.

Declaration of interest: There is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.

Funding: No specific grant from any funding agency in the public, commercial or not-for-profit sector.