Medical mystery: Back pain plagued her for 30 years. A recurring clue sparked a delayed diagnosis.

As a 16-year-old high school volleyball star, Charlene Gervais dreaded what long bus rides did to her lower back. Away games in northern Minnesota meant more than an hour rumbling along rural roads, trips that left her stiff and sore. The pain in her spine and hips receded once she began playing, only to fire up when she headed home. And it flared at other times, usually without an obvious trigger.

As a teenager, Gervais saw a chiropractor for back pain. “My parents were big fans” as was her family doctor of the treatment that involves spinal manipulations aimed at lessening pain.

Gervais said the chiropractor told her she was suffering from spinal misalignment.

“There never seemed to be much of a pattern,” Gervais recalled. She noticed that her condition tended to be worse when she woke up in the morning and improved if she moved around. Sometimes months would go by without any pain.

As an adult Gervais, now a 54-year old Chicago brand strategy consultant, continued to see chiropractors and personal trainers whom she believed could recommend exercises to strengthen her body and treatments to manage her pain. She worked out faithfully at a gym and remembers periodically overdoing it in class.

“I’m competitive and would repeatedly hurt myself rather than scale back,” she recalled.

An avid traveler who has visited 100 countries, Gervais said she remained determined not to let her bad back slow her down. About 15 years ago she earned a pilot’s license, although climbing in and out of a small plane could be tough.

By her early 40s, after years of focusing on things other than her health, Gervais said it was becoming clear that her strategy of benign neglect was faltering. “For me, the method was just push on. I hadn’t spent a lot of time helping myself.”

Once she had to be carried up five flights of stairs to her office after her back locked. Sneezing was particularly fraught unless she was in a fetal position on the floor; otherwise it felt like “a grenade shooting up my spine.” To get to standing from a seated position, Gervais said, she sometimes rolled off the sofa and crawled around her house before attempting to stand.

Medications were largely ineffective. Anti-inflammatory drugs had stopped working, and opioids made her itchy and irritable.

Gervais’ longtime internist was sympathetic.

“She sent me to a lot of specialists — but none that could help me,” Gervais said. She saw an orthopedist and several physical therapists along with an occasional chiropractor. Gervais tried gait training to improve her walk and acupuncture to relieve the pain.

“I believed it was a muscle knot and that it would help,” she said. “I do trust people when they say they’re experts. And I give people the benefit of the doubt. I’m very loyal.”

While reading through her medical records, Gervais, then 46, said that one thing stood out: repeated references to her joints. An online search for “doctors who fix joints” yielded websites about rheumatologists, internists, or pediatricians who specialize in the treatment of joints, muscles, bones, and the immune system. Gervais had never seen a rheumatologist and asked her internist for a referral to Arthur M. Mandelin, an associate professor of medicine at Northwestern University’s Feinberg School of Medicine.

Her initial appointment in June 2012 was “the most thorough workup I’ve ever had,” Gervais said.

Gervais remembers answering yes to a series of questions Mandelin posed: Do you have trouble standing after sitting for a long period? Are your symptoms alleviated after a walk? “It was the first time the right questions were being asked,” she said.

Based on her history and a physical exam, Mandelin told Gervais he suspected she had ankylosing spondylitis (AS), a form of chronic inflammatory spinal arthritis that causes stiffness and back pain. AS, which can affect other parts of the body, results from inflammation between the vertebrae and in the sacroiliac joints. The cause of the disease, which typically develops in late adolescence or early adulthood, is unknown but is believed to result from both environmental and genetic factors.

The disease has long been thought to primarily affect men, but recent research has suggested that it may have been overlooked in women, Mandelin noted. Treatment involves medications, exercise, and sometimes surgery.

Delayed diagnosis of AS, Mandelin said, is the rule, although the 30 years it took Gervais is on the longer side.

“Back pain is the common cold of musculoskeletal disease,” Mandelin said. There are many causes and sorting them out can be tricky, he said, adding that he had the benefit of Gervais’ long history as he tried to determine what might be wrong. “Most causes of chronic back pain don’t have great testing.”

Doctors may not have considered AS in Gervais’ case because they were unaware of it.

“There’s a maxim from my training: ‘Your eyes will not see what your mind does not know,’ " he observed.

Some people with AS delay seeking help because over-the-counter anti-inflammatory drugs are effective initially, then stop working because they are inadequate to treat the level of pain.

“The thing that caught my attention,” Mandelin said, “is that her back pain has these inflammatory features ... she had trouble first thing in the morning and improved after she moved.” The opposite would be true if her pain was the result of an injury: rest would lessen the pain.

“And there was no inciting event,” such as an injury, he noted.

Early diagnosis and treatment are important, Mandelin said. “Intervening early and aggressively has the best chance to control the disease” and reduce damage to the spine and other parts of the body.

To help confirm the diagnosis, Mandelin ordered blood tests, including one for HLA-B27, a protein found on the surface of white blood cells that increases the risk of developing AS but is not a screening test.

Gervais, whose test was negative, said she was elated to receive a provisional diagnosis and even happier shortly after starting a potent anti-inflammatory drug called indomethacin.

“It was literally life-changing,” she said. Within days “I could bend forward like a normal person.”

Her “exuberant” response to the drug was the clincher for Mandelin. “That was impressive,” he said. “In rheumatology, we have very, very few blood tests that are gold standard reliable.”

But Gervais was unable to tolerate the drug, which left her dizzy and confused. “I’d find myself just staring at my desk in a total fog,” she recalled.

She began receiving biweekly injections of Humira instead. The drug suppresses the immune system and is used to treat other forms of arthritis and Crohn’s disease, which sometimes accompanies AS.

“We were looking for medication that would keep things on a low simmer,” Mandelin said. The drug has worked well for Gervais, who has not experienced side effects. Her condition has remained stable for the past decade, said Mandelin, who sees her every six months.

Gervais said she now moves without difficulty. She walks five miles a day and works out three times a week without pain.

“I’m good — really good,” she said. A brief flare several months ago triggered by gardening left her wondering how she managed all those years.

“What stands out is the incredible frustration of not getting a valid diagnosis,” she said. “Why is it that nobody put it together?”