Mrs. NJ, a 65-year-old patient with diabetes and hypertension with IHD was brought to the ER in a drowsy state. She was hemodynamically stable, looked mildly dehydrated, and had no focal neurological deficits. There was no history of fever, convulsions, and head injury, and her investigations revealed that she was in severe renal failure – urea 290 mg% creatinine was 9 mg%, and her CBC, liver functions were normal. Her kidney size was normal on ultra-sonogram, and there was no gross proteinuria or microscopic hematuria on urine analysis. Her renal functions were normal 2 months before during a routine check-up.
This history and evaluation were suggestive of severe acute renal failure, the reason for which needed evaluation. She was taken on dialysis that improved her consciousness. On questioning, she revealed that she has been taking NSAIDs for body pain for the last one week.
She underwent 3 sessions of dialysis, and her kidney functions recovered.
NSAIDs and kidneys
NSAIDs are one of the commonly prescribed medications by different medical specialists and are also self-medicated and sold over-the-counter across pharmacies. They are one of the commonest groups of drugs that cause acute kidney injury (AKI). The two mechanisms by which they cause AKI are “hemodynamic’ and “acute interstitial nephritis” (AIN).
Hemodynamic AKI by NSAIDs
Fig 1: Blood flow in a glomerulus
Fig 2 – role of prostaglandins and NSAID-induced afferent arteriolar constriction
There could be immediate restoration of kidney function once the drug is withdrawn.
Acute interstitial nephritis(AIN) and NSAID use
AIN is another renal disease caused by NSAIDs. Unlike hemodynamic injury, stopping the drug will not improve the renal functions. There will be ongoing renal function worsening, and patients would need a renal biopsy that will show acute tubular damage and inflammatory infiltrates in the interstitium. It usually responds to steroids.
NSAIDs can also cause nephrotic syndrome, hyperkalemia, chronic tubule interstitial damage, and predisposes to urothelial malignancies..
NSAIDs are double-edged weapons. When used for the appropriate indications, they work wonders. Indiscriminate use, especially in elderly, those with deranged renal functions could cause renal dysfunction, and it is important to recognise and manage them by a nephrologist.
Chief Of Nephrology