What tick-borne illnesses cause cardiac side effects?

Tick-Borne Illnesses That Cause Cardiac Side Effects

Multiple tick-borne illnesses can cause cardiac complications, with Lyme disease, anaplasmosis, and ehrlichiosis being the most significant causes of cardiac manifestations that can lead to serious morbidity and mortality if not properly treated.

Lyme Disease Cardiac Manifestations

Lyme disease, caused by Borrelia burgdorferi, is the most well-documented tick-borne illness with cardiac involvement:

• Primary cardiac manifestation: Atrioventricular heart block (occurs in early-disseminated Lyme disease)

  • Usually occurs within 2 months after infection 1
  • Block typically occurs above the bundle of His, often involving the AV node 1
  • Can progress rapidly from first-degree to complete heart block 2

• Other cardiac manifestations:

  • Myopericarditis 1, 2
  • Non-ischemic cardiomyopathy (rare but documented) 3
  • Lyme endocarditis (extremely rare) 4

• Warning signs requiring hospitalization:

  • PR interval >300 milliseconds
  • Second or third-degree heart block
  • Symptoms such as syncope, dyspnea, chest pain 1, 2

Anaplasmosis Cardiac Complications

Human Granulocytic Anaplasmosis (HGA), caused by Anaplasma phagocytophilum:

• Can cause fatal myocarditis as documented in case reports 1
• A case of widespread transmural myocarditis with neutrophilic and lymphocytic infiltrates was confirmed by PCR and immunohistochemical staining 1
• Cardiac involvement can be life-threatening and may lead to sudden death 1

Ehrlichiosis Cardiac Involvement

Human Monocytic Ehrlichiosis (HME), caused by Ehrlichia chaffeensis:

• Can cause myocarditis as part of its severe manifestations 1
• Severe manifestations of ehrlichiosis include myocarditis, meningoencephalitis, and multiple organ failure 1

Rocky Mountain Spotted Fever (RMSF)

• Cardiac complications can include:
  • Myocarditis
  • Arrhythmias
  • Hypotension due to vasculitis 1

Diagnostic Considerations

• Cardiac manifestations may be the presenting symptom or occur alongside other symptoms of tick-borne illness
• Patients with Lyme carditis are typically seropositive at presentation (>90%) 1
• ECG should be performed in patients with symptoms suggesting cardiac involvement 2
• Consider tick-borne illness in patients with unexplained conduction abnormalities, especially during spring and summer months 5

Treatment Approach

• For Lyme carditis:

  • Hospitalized patients: IV ceftriaxone until clinical improvement, then transition to oral antibiotics to complete 14-21 days 1, 2
  • Outpatients with mild disease: Oral doxycycline, amoxicillin, or cefuroxime axetil 2

• For anaplasmosis and ehrlichiosis:

  • Doxycycline is the drug of choice for all ages 1
  • Treatment should be initiated empirically when suspected 1

• For RMSF:

  • Doxycycline is the treatment of choice for all ages 1
  • Prompt treatment is critical as mortality increases with delayed therapy 1

Prognosis

• Lyme carditis: Excellent prognosis with appropriate treatment; most patients recover completely with no permanent cardiac sequelae 2, 6
• Anaplasmosis and ehrlichiosis: Can be fatal if not recognized and treated promptly 1
• RMSF: Has the highest mortality rate among tick-borne diseases in the US if not treated early 5

Important Clinical Pitfalls

• Failure to recognize cardiac involvement: Cardiac manifestations may be subtle initially but can progress rapidly
• Delayed treatment: Particularly dangerous with RMSF and anaplasmosis
• Misdiagnosis: Symptoms may mimic viral or idiopathic cardiomyopathy
• Permanent pacemaker placement: Should be avoided in Lyme carditis as conduction abnormalities are typically reversible with appropriate antibiotic therapy 2, 6

Remember that cardiac manifestations of tick-borne diseases can be life-threatening but are generally reversible with appropriate and timely antibiotic therapy.