20 INFECTIOUS DISEASES SEPTEMBER 2010 • PEDIATRIC NEWS Lyme Prophylaxis Risk Often Outweighs Benefit

In a study involving prophylaxis with doxycycline, of New England, the Mid-Atlantic states, borne pathogens, Dr. O’Leary said that and the upper Midwest. And prophylax- fewer than 1 in 1,000 30% of patients had adverse events. is can be started less than 72 hours after carry Rickettsia rickettsii, the cause of removal of the . Rocky Mountain spotted fever. And BY BRUCE JANCIN Diseases Society of America (IDSA) When all those conditions are met, the while there are very few studies on oth- guidelines on the topic, he noted. IDSA guidelines state that it’s reasonable er tick-borne diseases, the risk is consid- FROM AN ANNUAL CONFERENCE to offer a single dose of doxycycline in ered “very, very low,” he noted. ON PEDIATRIC INFECTIOUS DISEASES The risk/benefit numbers argue against prophylaxis under most circum- patients without a contraindication to “In general, the risk of prophylaxis far VAIL, COLO. — Antimicrobial pro- stances, he continued. If a 1.4% attack the drug. The dose for Lyme prevention outweighs any potential benefit,” Dr. phylaxis for should not be rate of Lyme disease following a tick bite is 200 mg in adults and 4 mg/kg up to a O’Leary stressed. ■ used when a patient arrives at the clinic in an endemic area is assumed, the num- maximum of 200 mg in children above with a recognized tick bite, according to ber needed to treat in order to prevent 1 8 years of age. Disclosures: Dr. O’Leary said he had no Dr. Sean O’Leary. infection is 83 patients, said Dr. O’Leary As for prophylaxis against other tick- relevant financial conflicts. “This is actually a fairly common call of the Children’s Hospital and the Uni- to our infectious diseases division in the versity of Colorado, both in Denver. With the use of amoxicillin for pro- New Hampshire Had Highest Lyme Disease Incidence in 2008 The IDSA phylaxis, for every 10 cases of early Lyme (per 100,000 population) guidelines specify disease prevented, it’s to be expected that the limited 1 patient would develop a severe, life- circumstances in threatening drug reaction and 10 would which prophylaxis experience a drug-induced rash. And, in a is ‘moderately’ study involving prophylaxis with doxycy- favored. cline, 30% of patients had adverse events. The IDSA guidelines specify the limit- DR. O’LEARY ed circumstances in which prophylaxis is DC “moderately” favored. summertime: ‘I had a child come into The tick must be reliably identified as <1 EWS the office. We’ve got the tick. What do an adult or nymphal scapularis, N 1-20 we do?’” he said at the conference spon- commonly known as the deer tick, that’s sored by the Children’s Hospital, Denver. been attached to the skin for more than 21-50 EDICAL The answer he and his pediatric 36 hours based upon the extent of en- M 50-90

infectious disease colleagues at the hos- gorgement with blood. LOBAL pital almost always provide is a strong The local rate of infection of this tick 92 G “no” to antimicrobial prophylaxis. That’s species with Borrelia burgdorferi has to Source: Centers for Disease Control and Prevention LSEVIER consistent with detailed Infectious exceed 20%, as is generally true in areas E Misdiagnosing Tick Can Lead to Death in 10%

BY BRUCE JANCIN ysis with preserved sensorium, particularly when there is a history consistent with potential tick exposure. FROM AN ANNUAL CONFERENCE ON PEDIATRIC INFECTIOUS DISEASES Treatment of tick paralysis is simple: Remove the tick. Clinical improvement will follow within hours. VAIL, COLO. — Tick paralysis is often misdiag- In unrecognized and untreated cases of tick paral- nosed—with potentially dire consequences—as one of ysis, however, the fatality rate is about 10%, with

the other diseases that cause an acute ascending paral- death typically occurring just 18-30 hours after symp- /CDC ysis with preserved mental status. tom onset, according to Dr. O’Leary of the Children’s

The -inflicted paralysis is most often Hospital and the University of Colorado, both in ATHANY confused with Guillain-Barré syndrome. Other causes Denver. G AMES

of an acute ascending paralysis with preserved mental Tick paralysis is more common in children than J status include spinal cord tumors and acute adults. The highest-risk group is young girls with long poliomyelitis. Botulism, in contrast, causes a descend- hair that can readily hide an engorged tick that’s had a OURTESY ing paralysis with preserved mental status, Dr. Sean blood meal. At 3 days after attachment, the tick (usu- C O’Leary said at the conference sponsored by the ally a female) begins secreting the that caus- The Rocky Mountain wood tick Children’s Hospital, Denver. es the paralysis. Symptoms appear 4-7 days after is a vector of Rocky Mountain spotted fever. Conducting a thorough search for an embedded tick attachment. is essential in a patient with an acute ascending paral- The peak time for tick paralysis is tick mating season: About 8% of the 870 named tick species have been April through June. associated with intoxication syndromes. The clinical scenario The species that cause the most cases of human, dog, The How-Tos of Proper Tick Removal typically begins with loss and livestock paralysis in North America are Derma- of appetite and voice, fol- centor andersoni and D. variabilis, both of which are vec- he proper way to remove a tick release more of the infectious lowed by gait instability, tors for the rickettsial disease Rocky Mountain spotted Tis to grab it with blunt forceps as organism or , he noted. ascending flaccid paraly- fever. In the United States, tick paralysis occurs most close to the skin as possible and pull Don’t handle the tick barehanded. sis, excessive salivation, often in the Pacific Northwest and Rocky Mountain it straight out with steady pressure, “There have been documented eye irritation, pupil asym- states. according to Dr. O’Leary. cases of disease transmission” in metry, and vomiting. The tick toxin’s pathogenic mechanism isn’t fully un- Don’t apply a hot nail or blown- people who did that, said Dr. Death usually is from derstood. Australian investigators have reported that the out match to the critter’s backside. O’Leary. . For toxin inhibits release at the neuromus- Don’t use tweezers or sharp And although in bygone days, it more than half a century, cular synapse, but tick paralysis there is caused by Ixodes forceps. was a popular practice to apply there have been post- species, and it’s not clear that the same mechanism is Avoid using a twisting or corkscrew gasoline, lidocaine, petroleum jelly, mortem reports of ticks at work in the paralysis caused by Dermacentor species, motion in removing the tick. or other substances to the embedded being found embedded in Dr. O’Leary said. ■ Don’t crush or squeeze the tick’s tick to encourage it to back out, the the skin of people who body, as that can cause the tick to current thinking is, don’t do it. died suddenly of unex- Disclosures: Dr. O’Leary said he had no relevant financial plained paralytic illnesses. conflicts.