Pyonephrosis
The kidney is converted into a multilocular
sac containing pus or purulent urine. Pyonephrosis can result from infection of
a hydronephrosis, follow acute pyelonephritis or, most commonly, arise as a
complication of renal calculus disease. Pyonephrosis is usually unilateral.
Clinical
features
The classical triad of symptoms is anaemia,
fever and a swelling in the loin. When the condition arises as an infected
hydronephrosis, the swelling may be very large and the -pyrexia very high and
associated with rigors. Symptoms of cystitis may be prominent.
Investigations
The plain radiograph may show a calculus and
an ultrasonogram will demonstrate dilatation of the renal pelvis and calyces.
The intravenous urogram will show poor function and the features of
hydronephrosis on the affected side.
Treatment
Pyonephrosis is a surgical emergency because
the patient is threatened with permanent renal damage and a potentially
Renal carbuncle
An abscess may form in the renal parenchyma as
the result of blood-borne spread of organisms, especially coliforms or Staphylococcus
aureus, from a focus elsewhere in the body. Occasionally the condition
results from infection of a haematoma following a blow to the kidney. Renal
carbuncle is most commonly seen in diabetic patients, intravenous drug abusers,
those debilitated by chronic disease and patients with acquired
immunodeficiency.
Pathology.
The renal parenchyma contains an encapsulated necrotic mass.
Clinical
features. There is an ill-defined tender swelling in the loin, persistent
pyrexia and leucocytosis, signs that closely simulate those of perinephric
abscess. In early cases there is no pus or bacteria in the urine but they appear
after a day or so. Urography shows a space occupying lesion in the kidney which
may be confused with a renal adenocarcinoma on ultrasonography and CT (Fig.
64.31).
Treatment.
Resolution by antibiotic treatment alone is unusual. Formal open incision of the
abscess may be necessary if the pus is too thick to be drained by percutaneous
aspiration.