Toxin From Tick Bite Paralyses Girl, Stumps Physicians
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.
- 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.