A patient with autosomal recessive Pseudohypoaldosteronism Type 1 (arPHA1) may develop a pulmonary syndrome caused by an increase in free lung water.
Patient selection: child with autosomeal recessive pseudohypoaldosteronism Type 1
Mechanism: a systemic loss of function in the epithelial sodium channel (ENaC) results in an inability to resorb free water in the lungs
The onset of pulmonary symptoms usually start during infancy. The episodes become less frequent and severe over the age of 5 years.
Clinical features - recurrent episodes with:
(1) chest congestion
(2) coughing
(3) wheezing and crackles
(4) tachypnea
Laboratory findings:
(1) may be negative for pulmonary infection (negative Gram stain, cultures, etc)
(2) increased sodium in sweat and saliva
Differential diagnosis:
(1) cystic fibrosis
(2) immunodeficiency
(3) asthma
