Acute Interstitial Nephritis (AIN)

Exam Cram

• Acute interstitial nephritis (AIN) is usually caused by an immune reaction to a drug

• Presentation: acute rise in creatinine with non specific symptoms (e.g. fatigue)

• Causes: sulphonamides, co-amoxiclav & NSAIDs

• Management: stop drug, supportive

Outline

Background

• Also called tubulointerstitial nephritis

• Usually occurs within 60d of exposure

• Accounts for 10% of AKI

Assessment

History

• Recent drug change, e.g. antibiotics

• Global deterioation

Examination

• Hypertension

• Rash- maculopapular

• Fever

Investigations

• Eosinophilia

• Raised IgE

• Urinalysis: protein, RBC and leukocytes

Diagnosis

Diagnostic Criteria: kidney biopsy (gold standard)

Differentials: pre-renal AKI, Acute Tubular Necrosis 

Classification (location, severity): 

• Aetiology

  • Drugs

    • NSAIDs

    • Sulphonamide

    • Quinolones, Macrolides, amoxicillin, cephalosporins, 

(Acronym: Not So Quick MAC)

Management

• Supportive

• Stop offending drug

Renal Reg Notes

Resources and References

Written in 2025