MIAMI (CBSMiami) — Imagine waking up to pain that is so debilitating that it prevents you from walking. It’s happening to a growing number of people and often undiagnosed.

“I just got up one morning and the pain just started,” Daphne Cuebas said.

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The excruciating leg pain struck without warning and left Cuebas completely powerless.

“I can’t eat, I can’t sleep, I can’t function,” Cuebas said.

Alexandra Annaloro, 21, suffers from the same pain. She said sometimes her leg shakes so uncontrollably that she can barely walk.

“I can’t walk for 10 minutes. Once 10 minutes is up, I’m done,” she said. “There’s days that I cry a lot. It’s hard.”

Cuebas and Annaloro both suffer from a chronic illness called Complex Regional Pain Syndrome or CRPS. It can strike anyone, anywhere, at any time.

“You can have a small injury like a sprain. You could walk and just miss a step or something like this and you can have a very, very debilitating pain that does not respond to treatment,” Dr. Sudhir Diwan said.

Diwan, a pain management specialist, called the disease mysterious and said it has no clear cause, which makes it even more difficult to diagnose.

CRPS is a disorder of the nervous system. It causes nerves to send constant pain signals to the brain.

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“We call it cross-talking of the nerves,” Dr. Diwan said.

The disorder typically affects the arms and legs and causes burning, swelling, and sensitivity to the slightest touch.

It got so bad for Cuebas that she said she quit her job and contemplated doing something far worse.

“I actually thought of ending my life. It came to that extreme,” she said.

Doctors believe that Annaloro’s CRPS was caused by a car accident.

“Every day is like a different battle,” Annaloro said.

There is no cure for CRPS, but doctors can help patients manage their pain with physical therapy and by implanting a spinal cord simulator that sends electrical signals to dull pain.

Cuebas said she has also started using a device called an “internal pain pump.” The pump was surgically implanted into her side and delivers morphine directly to her knee.

Annaloro and Cuebas said they have not given up on a cure.

“I think there’s hope in the future,” Annaloro said.

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Doctors said that treatment for CRPS is most effective when started early.