Lyme Carditis Without Typical Lyme Disease Symptoms
Lyme carditis can occur without typical Lyme disease symptoms. A 70-year-old man developed heart block from Lyme carditis despite having no rash, no recalled tick bite, and no classic Lyme disease symptoms. The case highlights why clinicians in endemic areas should consider Lyme testing in patients with unexplained cardiac conduction abnormalities.
Why Lyme Carditis Can Be Difficult to Diagnose
The authors describe a 70-year-old man who presented to the hospital without any typical Lyme disease symptoms but complained of progressive orthopnea and dyspnea on exertion.
His medical history complicated the picture. The patient had hypertension and calcific aortic stenosis, conditions that could easily explain his cardiac symptoms. Nothing about his initial presentation clearly suggested Lyme disease.
Laboratory findings were notable for an erythrocyte sedimentation rate of 136, white blood cell count of 16.6, hemoglobin of 9.3, and creatinine of 2.6. Liver enzymes were normal. Troponins were negative but his brain natriuretic peptide was elevated at 877.
His admitting EKG showed bradycardia with a heart rate in the mid-40s and a first-degree AV block.
Initial Differential Diagnosis
Given the patient’s comorbidities and laboratory findings, clinicians initially considered several possible causes:
- Anemia (hemoglobin 9.3)
- Progressive kidney disease (creatinine 2.6)
- Congestive heart failure exacerbation (elevated BNP)
- Worsening aortic stenosis
- Pneumonia
Each explanation was reasonable based on the clinical presentation. However, clinicians also considered the patient’s geographic location.
“Due to the prevalence of Lyme disease in the northeast and the patient’s symptomatology, a tick panel was ordered which came back positive for Lyme,” the authors reported.
The decision to test for Lyme disease despite the absence of classic symptoms proved critical.
Atypical Presentation of Lyme Carditis
“We report a case of a 70-year-old male with Lyme disease presenting with a second-degree, Mobitz type 1 AV block.”
The progression from first-degree to second-degree AV block reflects the rapid conduction changes characteristic of Lyme carditis. Patients who initially appear stable may deteriorate quickly as inflammation affects the cardiac conduction system.
This case differed from the typical Lyme carditis presentation in several important ways:
- No erythema migrans rash — Only about 40% of Lyme carditis patients recall a rash
- No recalled tick bite — Many patients never notice a tick bite
- No classic Lyme symptoms — No fever, joint pain, or neurologic complaints
- Older patient with comorbidities — Competing diagnoses obscured the Lyme etiology
- Isolated cardiac manifestation — Heart block was the primary presenting feature
In regions where Lyme disease is common, unexplained AV block should prompt clinicians to consider Lyme testing.
In endemic areas, Lyme carditis may present with heart block even when patients lack rash or typical Lyme symptoms. Clinicians should maintain a low threshold for Lyme testing in unexplained conduction abnormalities.
Treatment and Recovery
The patient was treated with intravenous ceftriaxone and oral doxycycline.
He experienced complete resolution of symptoms with restoration of normal sinus rhythm and no AV block.
This response demonstrates the reversible nature of Lyme carditis when appropriate antibiotic therapy is started promptly.
Without treatment, the patient could have progressed to complete heart block, required permanent pacing, or died.
Why Geographic Context Matters
“This incidence shows the importance of having a Lyme disease diagnosis when regionally appropriate for patients who may present with no other signs or symptoms other than an AV block.”
The authors emphasize that regional awareness plays an important role in diagnosis. Lyme disease is highly endemic in the Northeast and Midwest United States.
This patient lived in the Northeast, which lowered the threshold for Lyme testing despite the absence of classic symptoms. Such awareness prevented a diagnostic delay that has proven fatal in other cases.
Clinical Takeaways
This case highlights that Lyme carditis may present without the typical features clinicians associate with Lyme disease.
- Lyme carditis may occur without classic symptoms such as rash or fever
- Unexplained AV block should prompt Lyme testing in endemic regions
- Older adults with comorbidities can still develop Lyme carditis
- Cardiac conduction abnormalities may be the only manifestation
- Prompt antibiotic therapy can reverse heart block
Frequently Asked Questions
Can Lyme carditis occur without a rash?
Yes. Only about 40% of Lyme carditis patients recall having an erythema migrans rash.
Can Lyme carditis be the only symptom of Lyme disease?
Yes. Some patients present with isolated cardiac symptoms such as AV block without fever, joint pain, or neurologic symptoms.
Should doctors test for Lyme disease in patients with unexplained heart block?
Yes. In endemic areas, unexplained AV block should prompt Lyme testing even when typical Lyme symptoms are absent.
Do older adults develop Lyme carditis?
Yes. Although younger adults are more commonly affected, Lyme carditis can occur at any age.
Can heart block from Lyme disease resolve?
Yes. Most cases resolve with appropriate antibiotic treatment.
