What is the treatment for bradycardia following a tick bite?

Treatment for Bradycardia Following a Tick Bite

Bradycardia following a tick bite should be treated as possible Lyme carditis with prompt administration of antibiotics (doxycycline or ceftriaxone) and temporary cardiac pacing if hemodynamically significant, with careful cardiac monitoring until resolution. 1, 2, 3

Initial Assessment and Management

Immediate Actions:

• Remove the tick if still attached using fine-tipped tweezers, grasping as close to the skin as possible and pulling upward with steady pressure 4, 5
• Clean the bite area thoroughly with soap and water, alcohol, or iodine scrub 5
• Assess hemodynamic stability and severity of bradycardia
• Obtain 12-lead ECG to evaluate for atrioventricular (AV) block, which is the hallmark of Lyme carditis 1, 6

Hemodynamically Unstable Bradycardia:

• Administer atropine IV for temporary blockade of severe bradycardia 7
• If unresponsive to atropine, initiate temporary cardiac pacing 2, 3
• Up to one-third of Lyme carditis cases may require temporary pacing 6

Antibiotic Treatment

First-Line Treatment:

• For adults: Intravenous ceftriaxone 2g daily OR doxycycline 100mg twice daily 2, 3
• For children ≥8 years: Doxycycline 4.4 mg/kg/day in 2 divided doses (maximum 100mg per dose) 5
• For pregnant women: Intravenous ceftriaxone (avoid doxycycline) 5

Duration:

• Continue IV antibiotics until AV block resolves (typically 48-72 hours) 2
• Complete a 14-21 day course with oral antibiotics after improvement 5, 2

Monitoring and Follow-up

• Continuous cardiac monitoring until resolution of conduction abnormalities 2, 6
• Most patients (>90%) experience complete recovery of cardiac function 6
• AV block typically improves within 48-72 hours of initiating antibiotic therapy 2
• Consider 30-day event monitoring after discharge to ensure complete resolution 2

Important Clinical Considerations

• Lyme carditis typically presents 2-4 weeks after tick bite but can occur earlier (as soon as 4 days after initial infection) 1, 2
• Look for concurrent symptoms of Lyme disease, particularly erythema migrans rash 1, 2
• Cardiac manifestations may include various degrees of AV block, myopericarditis, and rarely congestive heart failure 6
• Permanent pacemaker implantation is rarely needed as conduction abnormalities are typically transient 2, 3

Prevention of Future Tick-Borne Illness

• Use EPA-registered repellents containing DEET, picaridin, or permethrin on clothing 5
• Wear protective clothing (long sleeves, pants, socks) in tick-infested areas 5
• Perform regular tick checks after outdoor activities 5
• Consider prophylactic antibiotics only if all high-risk criteria are met: identified Ixodes species tick, attachment ≥36 hours, and bite occurred in a highly endemic area 5

Prognosis

The prognosis for Lyme carditis is excellent with appropriate antibiotic therapy, with most patients experiencing complete resolution of cardiac abnormalities 6. However, delayed diagnosis and treatment may lead to prolonged cardiac conduction abnormalities or rare complications such as dilated cardiomyopathy 6.