Unveiling Salt-Wasting Congenital Adrenal Hyperplasia in an Infant: A Diagnostic Challenge

Congenital adrenal hyperplasia (CAH) is a monogenic genetic disorder with autosomal recessive inheritance. CAH can be classified into three distinct types: salt-wasting, simple-virilizing, and non-classical. In terms of severity, the salt-wasting type is the most severe form of CAH. The identification of simple-virilizing and non-classical types is challenging due to the absence of salt-wasting symptoms that require hospitalization. In this report, we describe a two-month-old female infant who was admitted to the emergency room with a history of lethargy, vomiting, and diarrhea. During the physical examination, the patient was found to have dry mucous membranes, generalized pallor, hyperpigmentation of the external genitalia, clitoral enlargement, and ambiguous genitalia. Laboratory investigations revealed the following results: 17-OH-progesterone levels at 109.19 ng/mL (N:<1.70 ng/mL), testosterone levels at 11.18 ng/dL, morning serum cortisol at 1.7 μg/dL (N:3.7-19.4 μg/dL), hyponatremia (111 mmol/L), hyperkalemia (6.0 mmol/L), and hypochloremia (85 mmol/L). The abdominal ultrasound revealed hyperplasia of the bilateral adrenal glands (right>left), normal uterus and ovaries, and absence of bilateral testicles. A mutation in the CYP21A2 gene was established by genetic testing. A diagnosis of the salt-wasting type of CAH was made. After 11 days of treatment, the patient had improved and was discharged. At the age of 12 months, the mother observed morning erections and further clitoral enlargement. The administration of fludrocortisone and oral hydrocortisone resulted in substantial improvement. This case report aims to describe a rare instance of salt-wasting CAH and highlight the challenges related to the early identification and management of ambiguous genitalia, enabling prompt intervention to prevent irreversible outcomes.