NON GLOMERULAR DISEASE - INTERSTITIAL NEPHRITIS (Robbins pp 971/969)

Drug induced/Analgesic nephropathy

General: This is tubulointerstitial nephritis produced by certain drugs.

Clinical features / course: Acute tubulointerstitial nephritis (a term given to a group of diseases) occurs after taking methicillin, ampicillin, thiazide diuretics, NSAIDs etc. Evidence points to a hypersensitivity reaction to the drug. It is thought that the drugs act as haptens, and then when they are secreted by tubular cells – they combine with body proteins to become immunogenic ≫ driving the IgE mediated hypersensitivity + cell mediated immune reactions ≫ tubulointerstitial nephritis. Analgesic abuse nephropathy is the same ≫ pronounced papillary necrosis.

Treatment: Withdraw the offending drug. With analgesic abuse nephropathy ≫ removing the agent improves the nephritis ≫ but small % of transitional papillary carcinomas.

Urate nephropathy

General: This is when patients have too much uric acid in their blood.

Clinical features / course: There are three types. With each type, the basic principle is when uric acid crystals are deposited in the tubular lumen, obstructing ≫ therefore causing renal failure, necrosis of that area.

Myeloma kidney

General: This is when patients experience complications to their kidneys as a result of non-renal malignant neoplasm. Conditions in which myeloma is present include: 1) bence jone proteinuria + cast nephropathy, amylodoisis, ligh chain nephropathy.

Clinical features / course: Malignant neoplasms of bone marrow cause complications such as: hypercalcaemia, hyperuricaemia, obstruction of ureters, and their treatment cause complications as well. Proteinuria is symptom in 70% of patients.

Morphology: LM: Tubular casts (bence jones nephropathy)

Acute tubular necrosis

General: Characterised by destruction of tubular epithelial cells ≫ Acute renal failure.

Epidemiology/At risk individuals: Most common cause of acute renal failure

Clinical features / course: Two types: 1) ischaemic, 2) nephrotoxic. Nephrotoxic relates to the toxins/drugs that induce tubular cell injury. Ischaemia refers to altered blood flow to the kidney due to vasoconstrictors. Both of these cause tubular cell injury. Oliguria ≫ acute renal failure.

Morphology: LM: tubular necrosis with skip lesions, luminal casts, interstitial oedema.

Treatment: In the setting of toxins ≫ 5% mortality rate. In the setting of shock/sepsis ≫50% mortality rate.

Category: Pathology Notes