Diabetic Ketoacidosis Complicated by Cerebral and Pulmonary Oedema in an Adult

Diabetic ketoacidosis (DKA) is a life-threatening metabolic emergency. While cerebral and pulmonary oedema are recognised complications in paediatric populations, they are exceptionally rare and poorly characterised in adults. This case report describes an adult patient with severe DKA who developed both cerebral and pulmonary oedema during treatment. A previously healthy 36-year-old man presented with a two-week history of polyuria and polydipsia and progressive dyspnoea. He was alert and tachycardic and exhibited Kussmaul respirations. Initial investigations confirmed severe DKA: serum glucose 22.1 mmol/L, bicarbonate <4 mmol/L, and an elevated anion gap. Point-of-care ultrasound (POCUS) confirmed volume depletion. Management followed standard DKA protocol with cautious fluid resuscitation and intravenous insulin. At 11 hours post-presentation, after receiving 4 litres of fluid, the patient developed acute respiratory distress and a decline in Glasgow Coma Scale (GCS) to 12. Imaging confirmed non-cardiogenic pulmonary oedema and cerebral oedema with leptomeningeal enhancement. He was intubated, required inotropic support, and was transferred to the intensive care unit (ICU). Management included continued DKA treatment, dexamethasone for cerebral oedema, empirical antibiotics, and strict fluid regulation. The pulmonary oedema resolved, and a repeat computed tomography (CT) scan of the brain showed resolution of cerebral oedema. The patient was successfully extubated on day 6 and made a complete neurological recovery. This case highlights that cerebral and pulmonary oedema, though rare, can occur in adults with DKA. It underscores the need for vigilant monitoring for these complications even with standard, cautious management. A multifactorial pathophysiology is likely, requiring an integrated critical care approach for successful outcomes. Emergency and critical care practitioners should be aware of these potential life-threatening complications in adult DKA.