A 46-year-old Caucasian male (CM) with chronic back pain takes large doses of over-the-counter pain medications. He works 12-hour night shifts and has to take 15-20 pills, especially Motrin (ibuprofen) and Aleve (naproxen), during the shift and about the same amount during the day in order to "function."He went to the ER (emergency room) today because of his back pain. CBC and BMP are ordered.
Past medical history (PMH)
Motrin (ibuprofen), Aleve (naproxen), Advil (ibuprofen), Ultram (tramadol), Tylenol (acetaminophen).
Limited range of motion (ROM) of lower back, otherwise unremarkable.
BMP showed a creatinine of 3.3 mg/dL, BUN 25 mg/dL. CBC was normal.
The patient had a normal CBC and BMP one month ago.
What is the most likely diagnosis?
NSAIDs-induced renal failure.
What tests would your order?
Urine Na+ and creatinine.
The patient was admitted to the hospital and IVF were started.
UA was normal. Microscopy was negative for eosinophils. Renal ultrasound was WNL.
His creatinine improved to 2.2 mg/dL over the course of 2 days. He was making 2 L of urine per day and had no complaints. Back pain was controlled with Percocet (oxycodone with acetaminophen).
The patient was discharged home with a follow up BMP in one week.
NSAIDs-Induced Acute Renal Failure (ARF).
What did we learn from this case?
NSAIDs-induced ARF is a well-known complication of NSAIDs abuse. It is described in injured athletes who have an important game and take "mega" doses of OTC pain killers to play "through the pain".
NSAIDs can induce two different forms of ARF:
- hemodynamically-mediated due to local vasoconstriction
- acute interstitial nephritis (often accompanied by nephrotic syndrome).Patients with acute interstitial nephritis present with hematuria, pyuria, white cell casts, proteinuria (not present in our patient).
A third type of ARF is due to an allergic reaction, in this case eosinophilia and eosinophiluria are noted in the urine.