Chapters authored
Diagnosis of Hypoaldosteronism in Infancy
Hypoaldosteronism is associated with either insufficient aldosterone production or lack of responsiveness to aldosterone and can be isolated or in the context of primary adrenal failure. Τhe severity of clinical manifestations is inversely correlated to age, with the neonatal period being the most vulnerable time for a patient to present with mineralocorticoid insufficiency. Salt-wasting forms of congenital adrenal hyperplasia (CAH), adrenal hypoplasia congenita (AHC), aldosterone synthase deficiency (ASD) and pseudohypoaldosteronism (PHA) are all causes of hypoaldosteronism in infancy. Affected infants present with salt wasting, failure to thrive and potentially fatal hyperkalemia and shock. Α blood sample for the essential hormonal investigations should be collected before any steroid treatment is given, in order to confirm aldosterone insufficiency and to determine the underlying cause. Renal ultrasonography and urine culture are also useful for exclusion of secondary causes of aldosterone resistance. Initial management requires treatment of electrolyte imbalances and restoration of intravascular fluid volume. In case of a salt-wasting crisis, affected infants are usually treated initially with both hydrocortisone and fludrocortisone, pending the results of investigations. Interpretation of the hormonal profile will guide further therapy and molecular analysis of candidate genes.
Part of the book: Renin-Angiotensin Aldosterone System