Acute interstitial nephritis

Acute interstitial nephritis accounts for 25% of drug-induced acute kidney injury.

Causes

• drugs: the most common cause, particularly antibiotics
  • penicillin
  • rifampicin
  • NSAIDs
  • allopurinol
  • furosemide
• systemic disease: SLE, sarcoidosis, and Sjogren's syndrome
• infection: Hanta virus , staphylococci

Pathophysiology

• histology: marked interstitial oedema and interstitial infiltrate in the connective tissue between renal tubules

Features

Acute interstitial nephritis essential causes an 'allergy'-type reaction, so look out for urticarial-like rashes and a fever. Arthralgia is also a common feature. Classically urine shows elevated white cell counts and eosinophils. IgE is also often elevated.

• fever, rash, arthralgia
• eosinophilia
• mild renal impairment
• hypertension

Investigations

• sterile pyuria
• white cell casts

Tubulointerstitial nephritis with uveitis

Tubulointerstitial nephritis with uveitis (TINU) usually occurs in young females. Symptoms include fever, weight loss and painful, red eyes. Urinalysis is positive for leukocytes and protein.