Endocrine Abstracts

Introduction: Insulin oedema is an uncommon consequence of insulin therapy and may be overlooked in the differential diagnosis of bilateral limb swelling in paediatric patients. We report two cases of insulin oedema.

Case 1: An 11-year-old female with Type 1 Diabetes Mellitus (T1DM) and mild Diabetic Ketoacidosis (DKA) presented with blood glucose of 31.3 mmol/l, H of 51nmol/l, HCO3 of 14 mmol/l, and HbA1c of 130 mmol/mol. She received IV fluids and insulin as per local protocol. Three days later, she was re-admitted with progressive bilateral pitting oedema in the lower limbs. Clinical, bloods, and imaging investigations, including CT abdomen, revealed no evidence of underlying medical pathology. Initially managed with full maintenance fluid due to suspected diabetes-associated hypercoagulability, she was subsequently placed on fluid and salt restriction. The oedema improved spontaneously within two days, with complete resolution observed at a three-week follow-up.

Case 2: A 15-year-old boy presented with severe DKA (blood glucose of 30.6 mmol/l, H of 159nmol/l, HCO3 of 0, ketones of 3.4 mmol/l, and HbA1c of 128 mmol/mol) required intensive care. Weighing 37 kg (second centile), his renal function and other blood parameters were initially satisfactory. Following resolution of DKA, he was switched to an insulin sliding scale. A week into admission, he developed pedal oedema up to mid-thigh and gained 8 kg. This was accompanied by low serum albumin (25gm/dl) and mild renal impairment (urea of 8.9 mmol/l, creatinine of 87 mmol/l, urine protein/creatinine ratio of 51 mg/ mmol), which normalized within nine days as oedema resolved. Doppler and abdominal ultrasound results were normal. He was treated with enoxaparin and antibiotics due to the risk of deep vein thrombosis and a positive urine culture.

Conclusion: While insulin oedema is a diagnosis of exclusion, clinicians should maintain a high suspicion for it in patients newly initiated on insulin or after rapidly glucose correction. The first case was typical presentation of this condition, while the second was unusual due to renal impairment and low albumin with proteinuria after ketoacidosis resolution. Insulin oedema usually has a favourable prognosis, characterized by spontaneous resolution. However, some cases require diuretics. Clinicians should reassure patients to ensure insulin compliance.