Pyonephrosis.

The clinical and radiological features of pyonephrosis are reviewed, based on a consecutive series of 40 cases. There were 32 female and eight male patients, with a peak incidence in the 50-59 year age group. In 63% of cases the right kidney was involved. Almost all patients complained of loin pain and 48% had lower urinary tract symptoms. In 58% of cases a renal mass was palpable. An anaemia, pyuria and elevated blood sedimentation rate were usual. Plain films of the abdomen revealed enlargement of the outline of the involved kidney in 75%, ipsilateral absence of the psoas shadow in 63% and urinary tract calculi in 60%. At high-dose excretion urography a nephrogram was obtained in 58% of cases and a pyelogram produced in 34%. No single clinical or radiological entity emerged, there being an unbroken spectrum of disease ranging from infected hydronephrosis to xanthogranulomatous pyelonephritis. There is an increasing incidence of calculi, loss of the renal and psoas outlines and reduced renal function with increasing chronicity of disease. High-dose excretion urography is the investigation of choice since not only may the diagnosis be established but also there precise pathological state of the involved kidney. Further radiological investigation is infrequently required.