رجل عمره ٣٩ سنة في اليوم الرابع بعد إصابة رأس، صار مشوشاً أكثر ويشتكي صداعاً وغثياناً. الصوديوم نزل إلى ١٢٤، والبول قليل ومركز، ووزنه زاد قليلاً، ولا يوجد جفاف أو تورم. ما الأرجح وعلاجه؟

A 39-year-old man on day 4 after head injury is more confused with headache and nausea. Sodium has fallen to 124; urine is scant and concentrated, weight is slightly up, and there is no dehydration or oedema. What is most likely and its treatment?

1. Diabetes insipidus, treated with large fluid volumes
2. SIADH, usually treated with fluid restriction
3. Severe dehydration, treated with rapid fluids
4. Kidney failure, treated with immediate dialysis

Answer: B) SIADH, usually treated with fluid restriction. Inappropriate ADH retains water and dilutes sodium, with low concentrated urine. Treatment is fluid restriction and slow correction. Hyponatraemia worsens cerebral oedema and seizures.