Congenital Hypoaldostronism, a rare cause of intractable vomiting in infancy

Introduction: Renin- angiotensin-aldostrone system is a hormone system which can balance the blood pressure, electrolytes, body fluid and systemic vascular resistance. Therefore, any congenital or acquired defect of enzyme activity in this pathway leads to dehydration, electrolyte imbalance and decreasing blood pressure that can be life threatening and induce shock. The most prevalent cause of congenital aldostrone deficiency is congenital adrenal hyperplasia which can disrupt the production of cortisol and aldostrone simultaneously. However, aldostrone synthase deficiency, a very rare cause of adrenal insufficiency, result in a pure defect in aldostrone synthesis. In this article we present an infant who suffers from congenital hypoaldostronism.case presentation: A 45-day-old girl was admitted to the pediatric intensive care unit of our hospital due to fever and cough and respiratory distress with a diagnosis of pneumonia. She was from the orphanage and her family history was undetermined, with a medical history of low birth weight and admission in the neonatal intensive care unit in her neonatal period. After recovery from pneumonia, intractable vomiting was started. Work up of surgical, gastrointestinal, central nervous system and other systemic etiologies were normal except intermittent mild hyponatremia but persistent hyperkalemia. As a result of normal genitalia and absence of skin and mucosal hyperpigmentation, congenital adrenal hyperplasia seemed to be unlikely. The early morning cortisol level was 2 microg/dL, aldostrone was low considering the level of serum electrolytes and 17 OH progesterone was normal. To evaluate the ability of the adrenal glands to produce cortisol, ACTH stimulation test was done which leads to increasing the level of cortisol to 50 microg/dL. So congenital adrenal hyperplasia was rulled out. The only enzyme deficiency that could justify the clinical setting was aldostrone synthase deficiency. Treatment with fludrocortisone corrected the electrolyte imbalance and patient vomiting has stopped. In follow up, she could gain weight and her growth and development is normal.Conclusion: Intractable vomiting has a wide range of differential diagnosis. Although Electrolyte imbalance is a result of recurrent vomiting , Changes in electrolyte levels, such as hyperkalemia, may induce it in reverse. Congenital enzyme deficiency is a rare condition, however, it should be in mind in early childhood patients.

Keywords:

Hypoaldostronism , Congenital adrenal hyperplasia , Renin- angiotensin-aldostrone system