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INTERSTITIAL NEPHRITIS CAUSES
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
▪
Hepatorenal Syndrome
▪
Tropical
Interstitial nephritis as a cause of acute
kidney
failure
Drugs
Drugs are the commonest cause of acute interstitial nephritis,
the usual culprits being penicillins, non-steroidal
anti-inflammatory drugs (NSAIDs), and diuretics, but many others
have been implicated. The classical clinical picture is that a
few days or weeks after taking a drug the patient develops flank
pain (sometimes), fever, a skin rash, arthralgias, haematuria,
blood eosinophilia and elevated IgE, disturbed liver function
(sometimes), interstitial pneumonia (rarely), and
kidney
impairment, but
kidney
failure may be the only manifestation. The urine contains
protein and blood, with white and red cell casts. Proteinuria
may be in the nephrotic range, particularly in association with
NSAIDs.
The diagnosis can only be established with certainty by
kidney
biopsy, where typical histological findings are of an
interstitial infiltrate of lymphocytes and monocytes/
macrophages, together with some eosinophils. Epithelioid
granulomas may be seen, strongly supporting the diagnosis of a
drug-induced interstitial nephritis, but they are not
pathognomonic.
When large numbers of cells are present in the
kidney
interstitium the diagnosis is not contentious: more difficult
are those cases (not too infrequent) in which the infiltrate is
modest—how many cells turn 'acute tubular necrosis' into
'interstitial nephritis'? The importance of making the
distinction lies in the belief that, apart from withdrawal of
the offending drug, treatment of drug-induced interstitial
nephritis with steroids is beneficial. There is some evidence
that those given prednisolone (typical dosage 20 to 60 mg/day)
have an earlier and more complete recovery of
kidney
function than those left untreated.
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