Makindo Medical Notes

Related Subjects: |Metabolic acidosis |Lactic acidosis |Acute Kidney Injury (AKI) / Acute Renal Failure |Renal/Kidney Physiology |Chronic Kidney Disease (CKD) |Anaemia in Chronic Kidney Disease |Analgesic Nephropathy |Medullary Sponge kidney |IgA Nephropathy (Berger's disease) |HIV associated nephropathy (HIVAN) |Balkan endemic nephropathy (BEN) |Autosomal Dominant Polycystic kidney disease

Many studies have suggested an association between chronic ingestion of analgesics and kidney disease. Papillary necrosis is present histologically in almost all patients,

About

• Due to long term use of NSAIDS
• Also with Paracetamol and aspirin
• Cumulative dose of 3 kg or 1 g per day for more than three years
• Female > Male x 6 and most are over 45

Aetiology

• Most commonly with Propionic acid derivatives (fenoprofen, ibuprofen and naproxen)
• NSAID inhibition of renal prostaglandin synthesis and subsequent intra-renal vasoconstriction with Medullary ischaemia seems to be the initiating event.

Clinical

• Fatigue, malaise, oliguria, renal angle pain, Gastrointestinal symptoms 
• End stage renal disease, Oedema 
• Flank pain and haematuria if papillary necrosis occurs
• Hypertension and Acute kidney injury

Investigations

• FBC: anaemia. U&E: raised creatinine. Type IV RTA (Low renin and high K)
• Nephrotic-range proteinuria (80% of cases)
• USS: papillary necrosis (due to ischaemia of inner medulla) or garland pattern of calcification around the renal pelvis suggestive of prior papillary necrosis
• Non Contrast CT has been proposed as modality of choice to diagnose or exclude analgesic nephropathy- further research to validate this technique is needed
• Renal Biopsy: infrequently needed. as diagnosis made primarily by history and exposure shows interstitial nephritis; with NSAID there may be additional minimal change disease or membranous nephropathy. Later changes include areas of papillary necrosis and secondary focal segmental glomerulosclerosis, cortical scarring, and interstitial fibrosis

Management

• Discontinue analgesic use.
• Increase fluid intake, control blood pressure, monitor creatinine clearance 
• Monitor for transitional cell carcinoma of renal pelvis and ureters using checks for haematuria

References

• Analgesic nephropathy