ACUTE KIDNEY FAILURE

Specific causes of acute kidney failure

▪   Prerenal failure and acute tubular necrosis
▪   Vascular causes of acute kidney failure
▪   Nephrotoxic causes of acute kidney failure
▪   Glomerulonephritic and vasculitic causes of
    acute kidney failure
▪   Interstitial nephritis as a cause of acute
    kidney failure
▪   'Haematological' causes of acute kidney failure
▪   Hepatokidney Syndrome
▪   Tropical

Hepatokidney Syndrome

The hepatokidney syndrome consists of the association of severe and usually progressive liver disease with acute kidney failure. The kidney failure is characterized by: 

1. no evidence of kidney parenchymal damage (when kidneys from patients with the hepatokidney syndrome have been transplanted, they function normally in the recipient);
2. characteristic 'prerenal' urine biochemistry, in particular a very low urinary sodium concentration (<10 mmol/l);
3. no sustained response to volume expansion; and
4. exclusion of other causes of acute kidney failure.

The mechanism of kidney failure is uncertain, but is associated with markedly reduced kidney perfusion that may be due to excessive action of the vasoconstrictor endothelin.

One of the aims of the general management of patients with liver disease is prevention of the hepatokidney syndrome, the most important consideration being avoidance of known precipitants (drugs, excessive diuresis, delay in the treatment of sepsis). Nevertheless, the syndrome develops in up to 20 per cent of patients with cirrhosis admitted to hospital. There is no specific treatment and the prognosis is extremely poor. In the presence of potentially reversible liver disease, or with the prospect of liver transplantation, intensive therapy and kidney replacement therapy are justified. If these criteria are not met, then aggressive support is almost certainly inappropriate.