Frequency hyponatremia and syndrome of inappropriate antidiuretic hormone hypersecretion in children with lower respiratory tract infection

Lower respiratory tract infections(LRTI) is the most important cause of mortality and morbidity especially in developing countries. Hyponatremia, in daily clinical practice, is a frequent electrolite imbalance. Syndrome of inappropriate antidiuretic hormone hypersecretion(SIADH) is the most common cause of hyponatremia in the children with LRTI. Reasons of SIADH include also pneumonia, brochitis and bronchiolitis. Our study aims to analyse prevelence of dilutional hyponatremia secondary to SIADH in LRTI, risk factors for SIADH in LRTI patients and relationship between LRTI clinics and SIADH.100 hyponatremia patient diagnosed by LRTI are included in our study. LRTI cases were evaluated as clinically according to physical examination and radiological data. Serum and urinea osmolalities with together serum and urinea electrolites of all cases were checked.41 of our cases are female and 59 are male. Their age range between 1 and 209 months. 45 (%45) of our patients have acute brochilolitis, 44 (%44) have pneumonia and 11(%11) have acute bronchitis. 80 (% 80)of our cases have mild hyponatremia, 18 (% 18) have moderate hyponatremia and 2 (% 2) have severe hyponatremia. We determined SIADH in our 34 (% 34) hyponatremia patient. 11 (% 32) of 34 SIADH patients have pneumonia, 18 (% 53) have acute bronchiolitis and 5 (% 15) have acute bronchitis. SIADH is found mostly in children with acute bronchiolitis. Although infiltrations in chest x-rays is a risk factor for SIADH, we determined severity of LRTI or abundancy of pathological physical examination findings in LRTI cases is not a risk factor for SIADH development.As a result, we believe that hyponatremia in LRTI is a mild hyponatremia, SIADH is the cause of 1/3 of hyponatremia cases, bronchilolitis cases and infiltrations in chest x-rays are a risk factor for this syndrome, severity of hyponatremia and clinical status is not related to frequency so patient based fluid treatment should be done in all patients.Key Words: Lower respiratory tract infection, Syndrome of inappropriate antidiuretic hormone hypersecretion, Hyponatremia.