Chronic pyelonephritis

Chronic pyelonephritis is so o9ften associated with vesecoureteric reflux that some feel that it is better named ‘reflux nephropathy’. It is an important cause of renal damage and death from end stage renal failure.

Pathology

   There is interstitial inflammation and scarring of the renal parenchyma with a patchy distribution. The renal tubules are atrophic and dilated. The glomeruli retain their normal structure until the final stage of the disease.

Clinical features

   The condition is three times as common in women as it is in men.  Two –thirds of female patients are under 40 years of age, whereas 60% of male patients are over 40.

It is possible, but unusual, for chronic pyelonephritis to remain clinically silent until the symptoms of advanced renal insufficiency appear.

Lumber pain, dull and non-specific in character, is present in 60% of cases. Increased urinary frequency and dysuria are common. Hypertension is present in 40% of cases, may be malignant type. Constitutional symptoms of lassitude, malaise, anorexia, nausea and headache constitute the main complaint in 30% of cases.

   Attacks of low- grade fever often prompt the urinary tract investigations that bring the condition to light.

   Normochromic anaemia due to unsuspected impairment is an occasional presentation.

Investigations

    AS the glomeruli are relatively preserved, proteinuria is less marked than in glomerulonephritis (<3g daily). Casts are not usually present but white cells are plenty.

E.coli, Streptococcus faecalis, Proteus spp. or Pseudomonas spp. are found in the urine.

Treatment

   Treatment is aimed at eradicating predisposing contributory factors such as obstruction of stones and treating the infection, often with repeated course of antibiotics. Unfortunately, once the parenchyma has been scarred it becomes vulnerable to blood –borne organisms and reinfection is likely, sometimes with a different and resistant organism. Consequently, antibiotics confer only temporary benefit and progressive renal damage is common.

   Surgical treatment is indicated only when the disease is confined to one kidney. This is unusual but in such cases nephrectomy or partial nephrectomy may stop the symptoms of infection and make hypertension easier to control. Patients with end-stage renal failure require renal transplantation.