When Dr. Irene Gatti de Leon slipped on the ice and bumped her head, she wasn't too concerned. But two months later, she began to experience weakness in her right leg and right arm while she and her husband were visiting their daughter in suburban Chicago.

So she made an urgent appointment with Loyola University Medical Center neurologist Dr. José Biller, a fellow native of Uruguay whom she has known for years.

Biller ordered an immediate MRI scan, which showed a large subdural hematoma -- a mass of blood on the surface of the brain. With the hematoma compressing the brain, de Leon was in imminent danger of suffering permanent paralysis or cognitive deficits, similar to disabilities caused by strokes.

Biller referred de Leon to Loyola neurosurgeon Dr. Douglas Anderson, who stayed late to perform emergency surgery. Anderson drilled two holes in her skull and drained the hematoma, which was about 2 inches long and 1½ inches thick. De Leon has made a full recovery.

Subdural hematomas are triggered by head injuries that cause blood vessels between the surface of the brain and its outer covering (the dura) to stretch and tear. Subdural hematomas usually are caused by severe head injuries that cause bleeding, which rapidly fills the brain area. But less severe head injuries can cause chronic subdural hematomas. These slow bleeds may not cause symptoms for days or weeks.

De Leon's case "is an excellent illustration of why patients should not ignore neurological symptoms," Biller said.

Anderson said he collaborates closely with neurologists on brain surgeries he performs for neurological conditions, including hematoma, stroke, multiple sclerosis, epilepsy and Parkinson's disease. "We communicate and work together very closely," Anderson said.

Biller is chairman of the Department of Neurology and Anderson is a professor in the Department of Neurological Surgery of Loyola University Chicago Stritch School of Medicine.