Eruptive xanthomata in uncontrolled diabetes

Abstract

with a two-week history of worsening symptoms of thirst, polyuria and lethargy presented to the admissions department feeling generally unwell. Five days previously he had visited his general practitioner who had made a diagnosis of diabetes mellitus and treated the patient for a presumed urinary tract infection. The patient had an otherwise unremarkable medical history, he did not take any regular medications or abuse alcohol and his grandfather was the only family member with type 2 diabetes. The patient had small, yellow nodules located across his torso and upper arms (figure 1). He said that these nodules, ranging from 2–4 mm in diameter, had appeared over the preceding week or so. The rest of the examination, including fundoscopy, was normal. Routine blood biochemistry was undertaken: liver and thyroid function tests as well as urea and creatinine were normal. Abnormal results included a random glucose sample of 22.5 mmol/L, sodium 120 mmol/L and total cholesterol 24.7 mmol/L. Subsequent testing found that his high density lipoprotein (HDL) cholesterol was 2.2 mmol/L, triglycerides were 96.0 mmol/L and upon close inspection, the serum was noticeably lipaemic; and the lipid content was clearly visible after settling the specimen bottle in the fridge (figure 2). The patient commenced insulin therapy (Humalog Mix 25; 36 & 18 units) and was seen by both the diabetes nurse specialist and the dietitian for education and advice. After six weeks he was seen in the Outpatients Clinic and his blood biochemistry had improved: total cholesterol 7.8 mmol/L, HDL cholesterol 1.1 mmol/L, triglycerides 19.4 mmol/L and HbA1C 6.6%. Eruptive xanthomata or xanthoma diabeticorum appear in patients who have greatly elevated serum triglycerides, very low density lipoproteins (VLDLs) and chylomicrons. The lesions themselves consist of mainly triglycerides and small amounts of cholesterol. In severe cases, fundoscopy may reveal lipaemia retinalis, when blood vessels of the retina appear milky due to exudation of abnormal triglyceride-rich plasma. The low sodium in this patient was a spurious result due to