Four Advil and a glass of water had a permanent presence beside her bed.

Robin Mayhall would wake up, swallow the pain relievers and force herself back to sleep for another half-hour.

“Just let it kick in,” she remembered telling herself nearly 25 years ago before waking up and hobbling into a hot shower.

Mayhall, 47, said the daily limp out of bed got increasingly more difficult. Her knees became swollen, weak and not functional. Then a senior at the University of Texas, she was diagnosed with rheumatoid arthritis near her 21st birthday. And it was crippling her.

“The hot shower would usually finish helping me get going,” said Mayhall, who plans to ride in a racing wheelchair in the Louisiana Marathon half marathon Sunday.

“Back then, I had no idea you could get arthritis when you were 21 years old,” she said of her condition, a chronic inflammatory disorder affecting many joints, including those in the hands, feet and (in her case) lower body. “I didn’t know anything about it. I didn’t know there are all different kinds of arthritis that you can get at all different ages.”

Mayhall, a corporate communications senior writer for Blue Cross Blue Shield who moved back to Louisiana in 2001, remembered being scared. She struggled to make it to class. Like many 21-year-olds, she worried about getting a job after graduation.

Her body wasn't cooperating. Her pain was unbearable.

“Arthritis is a serious disease,” she said. “It’s not just aches and pains your grandma gets when the rain is coming and it makes her fingers hurt. I’m not knocking that. I’m not — not being serious. It can be life-threatening. It’s serious. It can put a formerly young, healthy person like myself in a wheelchair. It can change your life.”

Today, Mayhall works from a power chair. She’s mobile inside her home, able to walk from her residence to her car and from her car to work.

Within the past two years, her advanced medication has led to fewer side effects, fewer spikes of intolerable pain, not as much fever, fatigue and/or joint swelling. But she has noticed arthritis in her spine, affecting her mobility.

Her wheelchair, coupled with her story, sparked the idea that Mayhall should be Blue Cross’ rider this year in the half marathon.

“I use a wheelchair here in the office and somebody said, ‘You need to be the next rider. You need to do it next year,’ ” she said. “Everybody kind of laughed. Then it suddenly became not a joke and something I got serious about.”

Mayhall — after 25 years of consistent medication and treatment, including having both knees and hips replaced — will compete in an eight- to 10-person team, all of whom will don the company's “Together Strong” T-shirts.

All of this — most of a lifetime dealing with joints too swollen to function properly — began with what she believed was a spider bite. During a trip to Georgetown University for a conference near her 21st birthday, Mayhall woke up in an insect-infested dormitory room. The dorm had been closed for the summer, allowing a cluster of spiders and other insects to build a new bungalow.

“I got up one morning with my hand really red, swollen and painful,” she said. “I had a big bite that was clearly not a mosquito bite. It was about the size of a quarter. A big lump on the back of my hand — it was a mound.”

The bite eventually required exploratory surgery to assess the extent of damage to her right hand. The joints in her hand became too swollen and rapidly diminished her grip strength. Additional swelling in one knee followed. Then, the other knee joined. The symptoms for rheumatoid arthritis, mainly bilateral swelling, became more evident.

“Two weeks after surgery, my left knee swelled up,” she said. “I woke up one morning and my knee was just huge. It was so swollen and painful. I hadn’t had an injury or hit it or hurt it.”

Approximately a quarter-century later, Mayhall will take part in Sunday's half marathon. She will be pushed by two to three runners at a time, competitors who could spend their racing time otherwise, she noted.

“It wrecks their time to do the wheelchair pushing,” she said. “They aren’t able to run as fast as they normally would. These are folks that have been training and who could run the half marathon on their own and pursue a competitive time.”

But she’s thrilled — mainly because she knows she’ll finish first, she said with a laugh.

“One of the the things that’s kind of cool about being in the wheelchair is that, with my feet sticking out front, I will cross the finish line first out of our group," she said. "So they’ll do all the work, and I’ll get the best time. ... It’s really amazing.”