Quick-thinking pathologists at a Georgia tissue bank recently found Lyme disease in sudden cardiac death patients whose tissues were being examined for transplant use. The Centers for Disease Control and Prevention (CDC) reported details of those cases in an article published in the December 13 issue of the Morbidity and Mortality Weekly Report to alert pathologists, medical examiners, and coroners of the need to consider Lyme carditis in cases of sudden cardiac death. CDC investigators warned clinicians to check cardiac status in patients with Lyme disease and Lyme exposure in patients with acute, unexplained cardiac symptoms.
"Health-care providers should ask patients with suspected Lyme disease about cardiac symptoms and obtain an [electrocardiogram] if indicated. Conversely, they should ask patients with unexplained heart block about possible exposure to infected ticks. Health-care providers also should remind their patients of steps to prevent infection, including use of repellent, daily tick checks, prompt showering after potential exposure, and landscape management," the authors write.
3 Lyme Carditis Sudden Cardiac Deaths Reported Within 1 Year
"Lyme carditis is a known manifestation of Lyme disease. In surveillance data reported to CDC, approximately 1% of Lyme disease patients had Lyme carditis, which we define as second or third degree heart block. There were 4 previously reported deaths associated with Lyme carditis. What made these 3 new cases so striking is that they were reported within 1 year, from November 2012 through July 2013. We attribute that to the very astute pathologists at the tissue bank who recognized a pattern consistent with Lyme carditis. They not only recognized it but went through the appropriate channels to report and bring attention to it," lead investigator Joseph D. Forrester, MD, told Medscape Medical News.
"A goal of the...report is to alert pathologists, medical examiners, and coroners (particularly in high-incidence Lyme disease regions) [that] Lyme carditis can be a cause of some cardiac deaths," said Dr. Forrester, who is an epidemic intelligence service officer with the CDC's National Center for Emerging and Zoonotic Infectious Disease, Fort Collins, Colorado.
"We are involved with medical examiners and pathologists in several states looking for possible cases, but at this time we have no additional cases under investigation, and pathologists at the tissue bank reviewed reports for 20,000 cardiac specimens received since 2004 and found no additional cases," Dr. Forrester said.
Time to See a Physician About Lyme Carditis If…
"Symptoms of Lyme carditis that should prompt a person to see a physician include shortness of breath, light-headedness, fainting, palpitations, or chest pain, particularly if you are or have recently been in an area where there is a high incidence of Lyme disease," Dr. Forrester said.
According to the report, Lyme carditis symptoms occur a median of 21 days after infection and resolve within 1 to 6 weeks with appropriate antibiotic treatment.
The 3 cases included 1 woman and 2 men ranging in age from 26 to 38 years who were from states with high incidence of Lyme disease and who died of sudden cardiac death. In all 3 cases, cardiac tissue, corneas, skin, and other tissues had been recovered for potential transplantation. In 2 cases, evidence of Lyme carditis was discovered by pathologists at the tissue bank who were examining hearts for possible valve recovery. In the third case, CDC investigators confirmed Lyme carditis in heart tissues submitted for evaluation of suspected viral myocarditis. Lyme infection was confirmed by serology, and spirochetes were detected in the myocardium by immunohistochemistry in all 3 cases.
"The Borrelia burgdorferi spirochetes actually make it into the heart tissue. Whether the resulting carditis is due to the spirochetes themselves or to the immune responses to them or to a combination of both is unclear," Dr. Forrester said.
The most common manifestation of Lyme carditis is atrioventricular (AV) conduction blockade. Dr. Forrester said that sudden cardiac death might be the result of the conduction abnormality leading to fatal arrhythmia.
"I suspect that there are risk factors that make some people more susceptible to Lyme carditis," Dr. Forrester added.
Lyme Carditis Treatment Extremely Effective
"The current article further reiterates the importance of identification of Lyme carditis as a cause of heart block. I think this is more relevant to primary care physicians who manage the patients at the front end. The diagnosis of Lyme carditis can be challenging if it is the initial presentation of the disease process and [the] patient does not remember having a tick bite. AV block may be the first and only sign of Lyme disease," said Paras Karmacharya, MD, who recently reported a case of nonfatal Lyme carditis. Dr. Karmacharya, from Department of Medicine, Reading Health System, West Reading, Pennsylvania, was not involved in the CDC study.
"Although more than 90% of patients with Lyme carditis have complete recovery, patients with more severe conduction system disturbances (first-degree AV block with a PR interval >0.3 seconds, second- or third-degree AV block) should be referred immediately to the emergency department and hospitalized in a coronary care unit for treatment with intravenous antibiotics like ceftriaxone or high-dose penicillin G. Insertion of a temporary transvenous pacemaker may be required. As in the case described in our article, the degree of heart block can fluctuate from first degree to second degree to complete AV block very quickly in minutes to hours, so careful observation is prudent. Treatment with an antibiotic can revert the AV block within 48 hours of therapy, so identification of this potentially reversible cause of heart blocks may help prevent significant morbidity and mortality," Dr. Karmacharya said.
"Once you start treatment for Lyme carditis, the prognosis is excellent," Dr. Forrester emphasized.
No Risk for Lyme Infection Seen for Transplant Recipients
Recipients of transplanted corneas from 1 of the 3 Lyme carditis sudden death patients were subsequently treated prophylactically with doxycycline, but the CDC does not think there is a serious possibility of Lyme disease transmission from transplanted tissues.
Dr. Forrester said, "There has never been a documented case of Lyme disease transmission via transplanted organs, tissues, or transfused blood. Given how common Lyme disease is, such transmission would probably have happened if it were possible, so we feel that there is no such risk."
Recommendations for Avoiding Infection
Dr. Forrester, who has long been active in climbing, kayaking, and other outdoors activities, told Medscape Medical News that he carefully follows all of the CDC's recommendations for avoiding tick bites, including use of tick repellent, showering as soon as possible after coming indoors, conducting a full-body tick check, examining gear and pets, and tumbling clothes in a dryer on high heat for an hour to kill remaining ticks.
"One thing this investigation has highlighted is the need for better methods of primary prevention for Lyme disease," Dr. Forrester said.
Dr. Forrester reported no relevant financial interests and Dr. Karmacharya have disclosed no relevant financial relationships.
Morb Mortal Wkly Rep. 2013;62:993-996. Full text
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Cite this: Sudden Cardiac Death in Untreated Lyme Carditis - Medscape - Dec 12, 2013.