Endocrine Abstracts

Mrs IP is a 79 year old lady with a past medical history of spleenic marginal zone lymphoma, diagnosed in 2007 and treated with chemotherapy. She has suffered two relapses but despite her diagnosis had remained generally quite fit and healthy until the recent issues. An IgM paraprotein was identified in the patient’s serum an December 2014.

In April 2015 Mrs IP presented to her GP complaining of cramping symptoms overnight, especially marked in her hands, weight loss, fatigue, poor appetite with night sweats on and off over the past few months. Blood tests revealed an elevated ALP and a random glucose of 1.5 mmol/L. At this point she had an urgent referral to the Endocrine team where similar results for the plasma glucose were obtained, HbA1c was 33 mmol/L with a lymphocytosis. On examination there were no lumps anywhere and radiologically there was no sign of relapse. LDH was 563 U/L, ESR just above normal at 37 mm/h, cortisol 288 nmol/L, IGF-1 80 ug/L, insulin 32.1 U/L, C-peptide 1433 pmol/L (the latter two were non-fasting samples) and magnesium 0.84 mmol/L. Importantly there was a failure to demonstrate Whipple’s triad as the patient was asymptomatic at the time of the documented hypoglycaemia. Glucose, measured on the Radiometer ABL 800 Flex analyser, was 7.0 mmol/L in comparison with 0.6 mmol/L obtained by the hexokinase method on the Beckman Coulter AU 8500. Examination of the blank and reaction OD in the glucose measuring cuvette of the Beckman-Coulter AU revealed interference in the blank measurement typical of that observed with a paraproteinaemia.