Letters

Urinary tract infection in children How vigorous should investigation be?

In general radiological practice plain radiography and ultrasound examination of the renal tract seem to be a practical means of identifying children who need surgical intervention to correct obstruction, calculus, severe anomaly, or gross reflux.³ If the remaining children are treated with antibiotics until the infection has stopped is there a need to investigate and monitor them with such vigour?

Before we devote so much of our limited radiological resources and so much radiation to this cause can we be assured that the results of this massive radiological programme will affect the clinical management of these children in such a way as to result in a predictable benefit? If so it should be possible to calculate the cost and decide whether we can afford it.

M Brindle

Queen Elizabeth Hospital, King's Lynn, Norfolk PE30 4ET

1. Smellie JM, Poulton A, Prescod NP. Retrospective study of children with renal scarring associated with reflux and urinary infection. BMJ 1994;308:1193-6. (7 May.) [Abstract/Free Full Text]
2. Stokland E, Hellstrom M, Hansson S, Jodal U, Oden A, Jacobsson B. Reliability of ultrasonography in identification of reflux nephropathy in children. BMJ 1994;309:235-9. (23 July.) [Abstract/Free Full Text]
3. Sherwood T, Whitaker RH. Initial screening of children with urinary tract infections: is plain film radiography and ultrasonography enough? BMJ 1984;228:827

Intravenous urography is now superseded for reflux

EDITOR, - I agree with Eira Stockland and colleagues that renal ultrasonography alone cannot be recommended for the detection of reflux nephropathy.¹ It is, however, still useful, not only because it can detect major malformations and dilatation of the urinary tract but because renal length and therefore growth may be measured accurately.^2,3 I hope that the authors' use of intravenous urography as the gold standard will not increase the number of requests for this investigation. Studies have shown that scintigraphy with dimercaptosuccinic acid labelled with technetium-99m, to which the authors make only passing reference, is more sensitive than intravenous urography in detecting renal cortical scarring.^4,5 In addition, they have also shown a positive correlation between the cortical abnormalities detected by scintigraphy with dimercaptosuccinic acid and the degree of reflux. Therefore scintigraphy with dimercaptosuccinic acid should be adopted as the gold standard.

The dose of ionising radiation from scintigraphy with dimercaptosuccinic acid is considerably less than that from intravenous urography, and the procedure avoids the use of intravenous contrast. This further increases it desirability. At Guy's Hospital children with suspected reflux nephropathy are investigated by ultrasonography combined with scintigraphy with dimercaptosuccinic acid. This generally avoids the need for intravenous urography.

J A Holemans 

Department of Radiology, Guy's Hospital, London SE1 9RT.

1. Stokland E, Hellstrom M, Hansson S, Jodal U, Oden A, Jacobsson B. Reliability of ultrasonography in identication of reflux nephropathy in children. BMJ 1994;309:235-9. (23 July.)
2. Rosenbaum DM, Korngold E, Teele RL. Sonographic assessment of renal length in normal children. AJR 1984;142:467-9. [Abstract/Free Full Text]
3. Dinkel E, Ertel M, Dittrich M, Peters H, Berres M, Schulte Wissermann H. Kidney size in childhood. Sonographic growth charts for kidney length and volume. Pediatr Radiol 1985;15:38-43. [Medline]
4. Verber IG, Sturdley MR, Meller ST. 99mTc dimercaptosuccinic acid (DMSA) scan as first investigation of urinary tract infection. Arch Dis Child 1988;63:1320-5. [Abstract]
5. Elison BS, Taylor D, Van der Wall H, Pereira JK, Cahill S, Rosenberg AR, et al. Comparison of DMSA scintigraphy with intravenous urography for the detection of renal scarring and its correlation with vesicoureteric reflux. Br J Urol 1992;69:294-302. [Medline]