What caused woman's kidneys to fail?

This week we introduce a monthly feature exploring real cases that challenged local doctors -- at least for a while.

M.W., a 68-year-old great-grandmother, arrived in the emergency room at Massachusetts General Hospital vomiting, fatigued and essentially producing no urine.

"I had my husband drive me to the hospital because I've never been so sick in my life," she said in a recent interview.

The doctors looked at her abnormal lab tests and knew her kidneys were shutting down. But the cause of her kidney failure was unknown.

"This previously healthy woman was suddenly thrust into the complexities of renal failure and all the fear that goes with it," said her doctor, Hasan Bazari, a kidney specialist at Mass. General. "What was imperative was to determine the cause."

There are many things that can lead to acute kidney failure, including severe dehydration, an allergic reaction to medications, bladder obstruction, hypertension, infections, and diseases such as lupus and diabetes.

"The key to solving her case," Bazari said, "was to obtain the most information possible from her history and physical exam."

While M.W.'s ankles were swollen, consistent with a certain type of renal failure, there was little else wrong with her physical exam. She had no back pain to suggest the possibility of kidney infection. Her blood pressure was normal. She had no joint pain or rash, indicating an immune reaction in her kidneys, and no signs of trauma. A CT scan of the chest and abdomen offered no clues; no sign of an obstructed bladder and no sign of disease in any organ. But still, she was confused, nauseated, and her skin itched.

"I had seen several doctors before we finally made the two-hour trip to Mass. General," said M.W., who asked to be identified only by her initials. "No one knew what was wrong with me."

And they needed to figure it out fairly fast.

"Without an accurate diagnosis and proper treatment," Hasan said, "she could have become much sicker and died within weeks."

Kidney failure is frequently symptomless until late in its course, "when a patient has already lost one-half or even three-quarters of his or her total kidney function," said Brigham and Women's Hospital nephrologist Ajay K. Singh.

Ultimately, M.W. required intravenous steroids and dialysis. A large IV tube was inserted into a blood vessel in her groin and, for four hours at a time, a dialysis machine cleared the toxins from her body.

"It was horrible," she said. "I had to lie flat and couldn't move. My faith helped me a lot."

A clue in her history and a kidney biopsy finally revealed the cause of her kidney failure. "Her case was solved by asking the right questions," Bazari said.

A month earlier, M.W. had developed arthritis-like pain in her right shoulder, and she began taking ibuprofen. "I had started taking ibuprofen four weeks earlier, two to four every four hours, and pretty soon I was really taking it around the clock." While it is extremely rare, kidney failure can be caused by ibuprofen.

Nonsteroidal anti-inflammatory drugs, or NSAIDS, such as Advil, Motrin or Aleve, all can cause damage to the kidneys, as can COX-2 inhibitors such as Celebrex and Vioxx, Singh said. "Short-term high-dose or long-term habitual use of NSAIDs can be a problem."

To obtain a biopsy, a long needle was placed into M.W.'s back guided by radiology. Mass. General pathologist Dr. Robert Colvin examined her biopsy with both light and electron microscopes and confirmed Bazari's diagnosis.

"I found allergic inflammation in the kidney and damage to the filtering apparatus [glomeruli] in a pattern typical of NSAID injury," Colvin said.

Fortunately, NSAIDS like ibuprofen are an uncommon cause of renal failure. While tens of millions of people take these drugs, it is estimated that perhaps several hundred to a few thousand suffer any problems. NSAIDS can cause harm in two ways; they can either create an allergic response inside the kidney or decrease blood flow to the kidneys. In her case, it was an allergic response.

Most patients, like this former day-care worker, fully recover.

"I always figured if it was over-the-counter, it was safe and I could take as much as I wanted," M.W. said last week. "Now I know that is not true."

After 12 days in the hospital, M.W. returned home to her family with normal kidney function restored. The life-threatening episode means she has an allergy to NSAIDs and can never take them again. Her right shoulder pain (possibly arthritis or bursitis) has disappeared.

A version of this case study first appeared in The New England Journal of Medicine. Dr. Terry Schraeder can be contacted at tschraeder@aol.com.