A girl with progressive fatigue and hyponatremia: question

Excerpt

A 9-year-old girl was admitted to hospital due to emesis, fatigue and lethargy. She is the only child of unrelated Caucasian parents. Her mother has recently been diagnosed with Crohn’s disease and diabetes mellitus type I. During the 3 months preceding admission, the child had three episodes of gastroenteritis-like illness with vomiting and lethargy; for the two of these episodes, she was admitted to hospital where hyponatraemia was determined. The patient was treated with intravenous fluids, and she quickly recovered. The current episode was the fourth one of emesis and had started 24 h prior to admission, with recurrent abdominal pain and no diarrhoea. On the day of admission she deteriorated and became lethargic. She was afebrile. The mother had noticed progressive fatigue and weakness during the last few months as well as a weight loss of 5 kg. …