Duodenal web masquerading as pseudohypoaldosteronism of infancy

Abstract

Introduction: We present the case of a 5-month-old girl with duodenal web masquerading as pseudohypoaldosteronism (PHA). Case presentation: A 5-month-old girl born to first-cousin parents was referred to our institution for evaluation following two hospitalizations with vomiting and dehydration, associated with severe hyponatremia and hyperkalemia. She had a history of chronic emesis and failure to thrive, with a reportedly normal abdominal and renal ultrasound at her local hospital. Our initial evaluation confirmed hyponatremia, with elevated renin and aldosterone. The suspected diagnosis was PHA type 1. We started treatment with sodium supplementation following which her electrolytes normalized and subsequently she maintained normal electrolyte balance with relative improvement in weight gain and reduced emesis. Three months’ later, she re-presented with severe bilious emesis. Abdominal X-ray showed gastric dilatation indicating upper small bowel obstruction. Urgent ultrasound showed a grossly distended, fluid-filled, hyper-peristaltic stomach and duodenum, with obstruction distal to the third part of the duodenum. This was confirmed by upper-GI fluoroscopic study with findings suggestive of a duodenal web or duodenal stenosis/partial atresia. At laparotomy, a duodenal web was found and the patient underwent duodenojejunostomy. Following surg ery, the patient had complete resolution of emesis with normalization of electrolytes, renin and aldosterone. She no longer required sodium supplementation. Conclusion: This rare case highlights the presentation of transient PHA secondary to intestinal obstruction in an infant. In this context, transient PHA is due to gastrointestinal losses of sodium and water resulting in decreased renal perfusion from dehydration and consequent rise in renin and aldosterone. Keywords: Pseudohypoaldosteronism, Intestinal obstruction, Duodenal web, Hyponatremia, Hyperkalemia