Toxin From Tick Bite Paralyses Girl, Stumps Physicians

From the WebMD Archives

Jan. 12, 2000 (Washington) -- While it is known that certain ticks carry Lyme disease, the common wood tick can cause paralysis and even death if it is not promptly removed. That's the warning from doctors who treated a child in the hospital for two days before a tenacious physician-in-training discovered the eight-legged cause of the child's worsening condition. The child quickly recovered after the tick was removed. Writing in the Jan. 13 issue of TheNew England Journal of Medicine, the physicians describe the devastating effects of the tick bite.

The affected child was a six-year-old girl. In June 1998, she began complaining of a tingling sensation in her fingers, and within six hours was staggering when she walked. The following day she could not walk without help and was taken to the Medical College of Georgia in Augusta. By this time, about 30 hours had passed since her symptoms first appeared.

Once at the hospital, she underwent chest X-rays, MRIs of her head and neck, and other tests that revealed no abnormalities. Still her condition continued to worsen. Her speech was slurred, her arms and legs were becoming paralyzed and she could barely sit up. The physicians thought she had Guillain-Barré syndrome, a collection of symptoms that include sudden paralysis. There is no cure for this syndrome, and those who have it may suffer weakness for years after the initial episode. Treatment for this disorder includes plasmapheresis, in which blood is removed and returned to the patient, minus the plasma component.

At that time Carrie Davis Smith, MD, was in her third year of four-year training to be a pediatrician. She tells WebMD that she was in the child's room as preparations were being made for the plasmapheresis, and suggested that a tick may be the cause of the paralysis. She recalled dogs can harbor wood ticks and remembered that the child's grandmother had said how much she enjoyed playing with the family pooch. Smith was told that someone had already checked the child and found nothing, but she was undaunted.

Using the small black comb that is standard issue with other toiletries given to patients, Smith went section by section through the girl's hair. Stunning her colleagues, Smith discovered an engorged female tick stuck on the left side of the child's scalp.

"I think I yelled, 'Hey, y'all!' when I found it," Smith tells WebMD. "Then I got all excited. We paged Dr. Felz and he came running up and helped us take it off." Michael W. Felz, MD -- who has researched tick-borne diseases for a decade and runs a national tick identification registry -- first photographed the tick, and then kept it in a warmed petri dish in his office.

The tick found was not the kind that causes Lyme disease, but does carry Rocky Mountain Spotted Fever. If the tick is pregnant and feeding on a person, it produces an extremely potent toxin that can cause paralysis in humans and animals. Within 17 days, the tick produced 200 eggs. Both the tick and the eggs later died in Felz's office.

For her part, the child recovered quite rapidly. "We took the tick off about 3:18 p.m., and I was on call that night so I was checking her," Smith says. "You could watch her improve. It was just amazing to watch. Her grandmother and her mother, they were just so thankful. Here she was almost on a ventilator. It was really dramatic."

The child was hospitalized another 32 hours after the tick was removed, and subsequent neurological tests have been normal. Had the tick not been removed, it is likely that the paralysis that had first gripped her legs and then her arms would have continued ascending up her body, engulfing her lungs and making a ventilator necessary. The plasmapheresis, had it been performed, and any other aggressive interventions, would have been of no value.

Ultimately, the tick would have finished feeding and fallen off on its own, Felz says, but in cases where the person is not placed on a ventilator, death may occur before that happens. There have been reports of ticks being found during autopsies of patients who died of unexplained paralysis.

"A diagnosis of Guillain-Barre syndrome should not be accepted until a careful search has excluded the possibility that a tick is present. One may literally have to comb for the evidence," the authors write.

In an accompanying editorial, Herbert H. Schaumburg, MD, and Steven Herskovitz, MD, with the Albert Einstein School of Medicine in New York, recount their own recent instance of mistaken diagnosis, in which a technician applying electrodes for a EEG found a tick that had gone undetected in a child experiencing changes in consciousness.

These authors point out that botulism can also cause paralysis. "The report by Felz and colleagues is a lesson the perils of hasty diagnosis in children with ... paralysis," they write.

Vital Information:

  • A common wood tick that carries Rocky Mountain Spotted Fever can cause paralysis, and even death, in patients if it is not removed promptly.
  • If the tick is pregnant and feeding on a person, it produces a potent toxin that causes paralysis.
  • In a recent case report, a young girl recovered rapidly once doctors realized that a tick was causing her symptoms and removed it.