Lyme disease, which is also known as borreliosis, is a systemic illness characterised initially by a pathognomic rash erythema chronicam migrans, with associated vague flu-like symptoms. The disease is caused by the spirochete B burgdorferi
which is transmitted by tick bites. Lyme disease is the most common tick borne disease in North America and Europe. There are an estimated 20 000 cases of newly diagnosed Lyme disease/year in Hungary alone.2
In the UK 797 cases were identified during 2007 with an incidence of 1.49/100 000 total population.3
Approximately two thirds of indigenously acquired infections were acquired in southern counties of England (the south west and south east health regions). These areas include well known regional foci of Lyme borreliosis around the New Forest, Salisbury Plain, Exmoor, and the South Downs, parts of Wiltshire and Berkshire, and Thetford Forest. Other endemic areas include the Lake District, the Yorkshire moors and the Scottish Highlands and Islands.3
After an incubation period of 1–4 weeks, Lyme disease can involve various organs including the cardiovascular and central nervous systems, and joints. Conduction disturbances are the most common cardiac manifestation and can occur up to 87% of cases of Lyme carditis.1
Presentation with pericarditis, myocarditis, or pancarditis or with the insidious development of dilated cardiomyopathy is much less common. Conduction disturbances generally resolve completely with antibiotic treatment. A temporary transvenous pacemaker is sometimes required if the patient is very symptomatic with bradycardia. With adequate and early treatment complete heart block persists rarely more than a week. Permanent complete heart block is very rare.
Antibody detection remains the mainstay of laboratory support for a clinical diagnosis. It is insensitive in early infection as an IgG response takes some weeks to develop. The great majority of patients with established late stage infection are seropositive. Seropositivity alone is not sufficient to confirm a diagnosis of active Lyme disease. A positive antibody test may reflect past rather than current infection, though a high or rising titre provides useful supplementary evidence for active infection. Serological tests must be interpreted in the light of the clinical presentation and history of possible exposure. In the first phase of the disease, where erythema chronicum migrans is present, treatment with oral tetracycline is usually sufficient. In the second disseminated phase intravenous ceftriaxone is more effective because of better tissue penetration. In our patient the heart block resolved within a few days after starting the treatment.
The diagnosis of Lyme disease is not always obvious and its recognition is important if unnecessary implantation of a permanent pacemaker is to be avoided. Moreover, this case illustrates the importance a detailed history taking, including history of travel abroad.
- The diagnosis of Lyme disease is not always obvious and therefore a high index of suspicion is necessary.
- Good history is important for reaching a diagnosis.
- Lyme carditis usually presents with varying degrees of heart block and generally resolves completely with antibiotic treatment.
- Early diagnosis of Lyme carditis will prevent inappropriate implantation of a permanent pacemaker.