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Reminder of important clinical lesson
Extreme hyponatraemia with intact neurological outcome in a young child with Addison’s disease
  1. John-Paul Smith1,
  2. Christine Burren2,
  3. Yonas Cherinet1
  1. 1Department of Child Health, North Devon District Hospital, Barnstaple, UK
  2. 2Department of Paediatric Endocrinology and Diabetes, Bristol Royal Hospital for Children, Bristol, UK
  1. Correspondence to Dr John-Paul Smith, jposmith{at}


The authors present the case of a 6-year-old boy with a good neurological outcome from extreme hyponatraemia caused by autoimmune hypoadrenalism. He presented with 1 week of reduced appetite, lethargy, vomiting and one episode of diarrhoea. He was described as being slightly unsteady on his feet. Clinically he was alert, although intermittently confused, with dry mucous membranes and sunken eyes. Serum sodium was 96 mmol/l with normal serum potassium and renal function. He was initially treated with 3% saline intravenously, and his serum sodium increased to 128 mmol/l by day 3. He developed slurred speech and ataxia on day 4, although MRI brain showed no evidence of pontine myelinosis, and the symptoms resolved over 1 week. A Synacthen test on day 10 confirmed a diagnosis of Addison’s disease and he was commenced on hydrocortisone and fludrocortisone replacement therapy. At 5 months follow-up there are no obvious neurological or developmental sequelae.

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  • Competing interests None.

  • Patient consent Obtained.

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