As symptoms kept piling up, Elena Delle Donne couldn't help but think where they might lead.

"I was doubting my career - doubting whether I could be a professional athlete," Delle Donne said over the phone on Saturday.

Yes, Delle Donne's current back troubles, which kept her out of the second half of Sunday's Game 1 of the WNBA Finals, are tough stuff. Would she even be trying to play if the stakes weren't so high? Back spasms, however, aren't close to the toughest obstacle Delle Donne has dealt with this season.

Chronic Lyme disease has been part of her life for about five years, said Delle Donne, who turned 25 on Friday. She calls it an "extreme struggle." Earlier this season, she began losing the fight.

"The best way I can describe it, so people can relate to it, it's like when you have the flu and can't get out of bed," Delle Donne said. "I was feverish, shaky, exhausted - I also had migraine headaches."

Her hands would start to shake, Delle Donne said, and the tremors would go to her legs. All this was constant.

"I was like, crap, what do I do now?" she said. "I have to endure. But I knew it was coming back."

The first symptom, she said, was the deep fatigue. In June, the Chicago Sky had played the second of back-to-back games.

"In that game, I just knew I was completely depleted," Delle Donne said. "It never got better."

It all led to a kind of brain fog in which Delle Donne also had memory troubles. The tremors in her hands and legs appeared during games and practices. She made one of the tough choices in her life - to take a break, return home to Delaware, stay with her parents, and see the nurse-practitioner who has been working with her all along. According to the Wilmington News Journal, Delle Donne has been working for several years with Integrative Health Consults L.L.C. in Lancaster County.

"I was home for a month; she came every single day, Monday through Friday, for five hours," Delle Donne said.

Even if you don't know that the WNBA Finals are going on right now, you should realize that Delle Donne is one of the biggest stars in the game. If healthy, the unanimous choice for 2013 WNBA rookie of the year seems a lock for the next Olympic team. She was third in WNBA MVP voting her rookie season. The skills she showed in area gyms playing for Ursuline Academy and then for the Delaware Blue Hens remain rare in the top professional league in the world.

She's always read the game expertly. She's a 6-foot-5 forward who can think and act like a point guard while still getting to the weak side for a rebound. Her game draws people in.

But with all this pain, the only way to make it back, Delle Donne had decided, was to leave. Texts and other messages of support from teammates got her through it, she said. For a month, she was just a patient, taking a lot of herbal meds, she said, "a lot of IV treatment . . . I would get Vitamin C or even some antibiotics." When the symptoms went away, she had lost much of her stamina.

The WNBA season is short-ish, with a 34-game regular season, and Delle Donne missed exactly half of those games. Chicago, which had reached the Eastern Conference semifinals in 2013, barely slipped into the playoffs, grabbing the last Eastern spot with a 15-19 record. In the playoffs, Delle Donne became a force again, scoring 17 points in the fourth quarter of the decisive Game 3 of the Eastern semifinals against Atlanta, for 34 points overall.

It was in that series, however, that her back began acting up. By the end of the Indiana series, she was sitting out the second half of the deciding game.

"It's definitely improving," Delle Donne said Saturday. "I couldn't say I'm exactly 100 percent."

That was proven Sunday when she had to hit the bench after playing about 10 minutes, scoring two points. Game 2 is Tuesday night. Even if Delle Donne is at full strength, Phoenix is the big favorite, the overall top seed, led by Brittney Griner; Diana Taurasi; and Temple product Candice Dupree, who topped all scorers Sunday with 26 points.

The alternate underdog script, Chicago's coming back to win it all, may only be possible if Delle Donne's latest pain subsides again. The extreme struggle continues.

"It would be the most incredible thing ever," Delle Donne said before the series began, talking about winning the WNBA title. "It's always been a dream and goal. To do it this year would be one hell of a story."

mjensen@phillynews.com

@jensenoffcampus