Tubulointerstitial Nephritis

Occurs either through direct toxicity or because of an acute hypersensitivity

Drug-induced interstitial nephritis

Aetiology

  • Common drugs include ampicillin, rifampicin, thiazide diuretics, NSAIDs and allopurinol

Clinical presentation

  • Usually starts about 15 days after starting the drug
  • Patients usually have a fever and occasionally a rash

Investigations

  • Bloods can show eosinophilia

Management

  • With withdrawal of the drug most recover although there can be long lasting damage
  • In around a third the there is no obvious cause

Analgesic nephropathy

Aetiology

  • Said to be more common in women and usually in individuals taking multiple different kinds of analgesics over a long period

Pathophysiology

  • Patients develop papillary necrosis in addition to the tubulointerstitial nephritis

Clinical presentation

  • Patients usually develop anaemia and a range of non-specific symptoms e.g. headache
  • Many develop a UTI

Investigations

  • Bloods can show eosinophilia

Management

  • With withdrawal of the drug most recover although there can be long lasting damage
  • In around a third the there is no obvious cause

Other substances which are toxic to the kidney

  • Include urate, calcium and amyloid
  • Hyperuricaemia can occur in leukaemia patients on aggressive chemotherapy because of the nuclear damage as well as in a more chronic setting in gout
  • Multiple myeloma is associated with hypercalcaemia and amyloid deposition both of which are toxic to the kidney