ABSTRACT
This study aimed at detecting the attack rate and the associated risk factors of nephritis among sibling contacts after the appearance in the family of an index case with acute poststreptococcal glomerulonephritis [APSGN]. The study subjects included 51 patients admitted to the Nehrology unit of Alexandria University Children's Hospital with the diagnosis of APSGN and their 75 sibling contacts aged more than 2 years. APSGN was mainly pharyngitis-associated with peak incidence at winter and autumn and male preponderance. Eighty eight percent of the patients belonged to families of low socioeconomic status. Sibling contacts were examined once within one week of admission of the index case. They were subjected to history taking and had a physical examination, urinalysis and appropriate cultures. Antistreptococcal antibody titers and serum C3 were determined. Among the 75 sibling contacts, 30 of them showed evidence of nephritis whether overt [4 children] and subclinical [26 children] giving an attack rate of 40%, and subclinical to clinical ratio of 6.5. Almost 66% of the affected siblings came from families with a crowding index <=2/room. Group A beta-hemolytic streptococci [GABHS] were isolated from 15.7% of the index cases and 26.7% of the sibling contacts. T-typing pattern of the isolated GABHS revealed the following nephrogenic types; T3, 6, 12, 8, 8125llmp.19 and 3/13/B3264. In 80% of cases, the same serotype was isolated from the index case and his or her sibling contacts
Conclusion: asymptomatic APSGN adds much to the load of nephritis in our country. Young children living in overcrowded families under low socioeconomic conditions are at high risk of developing nephritis after the appearance of an index case in the family, improving the housing conditions will help in decrease transmission of streptococci with subsequent decrease of the incidence of nephritis