Young adults most at-risk for Lyme carditis

Cardiac involvement is a rare complication of Lyme disease. But it is estimated that up to 10% of patients in the U.S. with untreated Lyme disease go on to develop Lyme carditis, according to the authors of a recent study. And, young adults are most at-risk.

Lyme carditis often presents with non-specific symptoms, such as lightheadedness, syncope, dyspnea, palpitations, and chest pain, the authors explain. While an estimated 30% of patients exhibit no symptoms.

The most common clinical manifestation “is AV block, which can be acute in onset and can rapidly progress to complete heart block,” writes Carnazzo.

In their article, “Lyme disease presenting as complete heart block in a young man: Case report and review of pathogenesis,” Carnazzo et al. discuss the case of a young man with complete heart block as a complication of Lyme disease, who presented with symptoms months after several tick bites.¹

Interestingly, young adults, particularly males, are most at-risk for developing Lyme carditis, the authors point out.

“Clinical suspicion for Lyme carditis should be high for young patients with unexplained high grade heart block, particularly in Lyme disease endemic areas.”

Their case report describes a 37-year-old man who lived in northwestern Wisconsin. He presented to the emergency department with two episodes of syncope without prodromal symptoms which had occurred over a 5-day period.

“During these days, he had increasingly frequent episodes of dizziness and near-syncope,” writes Carnazzo.

“He also reported fever, chills, muscle aches, and bilateral lower extremity erythematous rash that had developed 3 weeks earlier that had resolved by the time of presentation.”

Two months before his symptoms began, the patient had removed several ticks from his left thigh and groin.

“Lyme carditis can be difficult to recognize in cases where classic signs of Lyme disease are not obvious upon patient presentation and EM rash or tick bite difficult to recall.”

An electrocardiogram (ECG) revealed complete heart block, so a temporary pacemaker was inserted.

The man was diagnosed with Lyme carditis after he tested positive for B. burgdorferi on Western blot and treated successfully with IV ceftriaxone.

After 9 days, the heart block had completely resolved.

The authors conclude:

• “It is important for clinicians to be familiar with the presentation and treatment of this infection that is now being observed in a wider geographic distribution so as to avoid serious long-term complications…”
• “Timely diagnosis and treatment of heart block due to Lyme carditis can lead to immediate and life-saving temporary pacing during initiation of antibiotic therapy, while avoiding unnecessary permanent pacemaker placement.”
• “Patients presenting with AV block should be asked about possible tick exposure, history of erythema migrans rash, recent travel to a high incidence Lyme disease area and other constitutional symptoms of Lyme disease like fever, fatigue, malaise, chills, muscle and joint pain.”