Pyelonephritis in Children. an Interim Review of Recent Literature.

Incidence of the Disease Among childhood infections those of the urinary tract are second in frequency only to respiratory infections, and are the commonest bacterial infections under two years of age (Pryles, 1960; Deluca, Fisher and Swenson, 1963). The incidence of overt urinary infections in the general population is estimated at 8 per 1,000 per annum (Percival, Brumfitt and Louvois, 1964), and in American schoolgirls at 1.4% of the school population per annum (Kunin, Deutscher and Paquin, 1964). Between I and 4%/, of hospital admissions of children are for this disease (Stansfeld, 1954); 3 to 4%/ of recent admissions to an acute p,ediatric ward in London were for urinary infections (Burke, 1961). On the other hand, in the Newcastle survey of 1,000 families, only 3 out of 847 children were noted to have pyelonephritis in five years; all relapsed. The incidence of "significant bacteriuria", which is often symptomless, (for definition see below) is higher, especially in girls; 1% of schoolgirls in a recent large American survey were found to have this (Kunin, Southall and Paquin, 1962; Kunin and others, 1964). Forty per cent of young women with symptomless bacteriuria in early pregnancy later developed pyelitis of pregnancy (KincaidSmith, 1964; Percival, Brumfitt and Louvois, 1964). The highest incidence of bacteriuria was found in girls aged between 15 and 19 (Kunin, Deutscher and Paquin, 1964). Most clinicians find that the onset of infection is most frequent under one year old (Stansfeld, 1954: Smellie, Hodson, Edwards and Normand, 1964), though some assert that the peak incidence is among girls aged three to five (Deluca, Fisher and Swenson; Gross, Randolph and Wise, 1963). But in infancy the diagnosis is often missed: in one autopsy series it had been missed clinically in 8.3% (Pryle and Neumann, 1962). T-he initial urinary infection often occurs in the newborn period; in one series 0.3%/, of hospital births (Smellie and others, 1964) and in another 1.5% (James, 1959) were considered to be infected. In fact, the incidence among the newborn may be higher than in other age groups; congenital defects in the kidney may predispose (Porter and Giles, 1956). Postmortem studies suggest that the prevalence of urinary infection is still underestimated (Kleeman, Hewitt and Gaze, 1960); about 2%/, of routine autopsies on American children disclose evidence of pyelonephritis (Pryles and Neumann, 1962; Spark, Travis, Dodge, Dalschmer and Hopps, 1962; Macaulay, 1964), but the difficulties in diagnosis of this infection from postmortem material must be borne in mind. An increased incidence of pyelonephritis in siblings has been noted (Kunin, Deutscher and Paquin, 1964).