부산대학교 도서관

In 22 out of 23 consecutive infants with bronchiolitis, 5.5±3.5 months of age, the syndrome of inappropriate ADH secretion (SIADH) was manifested by a 1.8±1.4% increase in body weight, increased urinary osmolality (Uosm) of 737±193 mmol/L with low plasma osmolality (Posm) of 275±4 mmol/L, and markedly elevated plasma ADH of 114±225 pg/ml (normal <3.5 pg/ml). SIADH, which usually suppresses plasma renin activity (PRA), was associated with increased PRA of 11-55 ng angiotensin 1/ml/h (normal for age <10 ngAl/ml/hr). Hyperaldosteronism was evident from the low fractional excretion (FE) of Na of 0.27±0.2% (normal 0.7±0.3%) and high FEK of 21±15% (normal 8±4.3%). Serum sodiums were normal. All the abnormalities returned to normal when bronchiolitis subsided. Thus, bronchiolitis of infancy is characterized by two abnormalities of water and electrolyte endocrine homeostatis. Both SIADH and hyperreninemia-hyperaldosteronism induced water retention. However, they counterbalanced each other with respect to serum Na, which remained normal. Bedside diagnosis can be obtained from the Posm-Uosm relationship, and the normal serum Na disregarded. Management should include water restriction.