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AMR - June 2006
Case Report - A 52-year-old Man with Increasing Fatigue and a Syncopal Episode
Darshana Sarathchandra, MD
HISTORY
A 52-year-old male marathon runner with a past medical history significant for glaucoma presented to the emergency department with a two-week history of increasing fatigue after an episode of syncope.
He initially presented to his primary care doctor’s office complaining of flu like symptoms one week after running a marathon and three weeks prior to admission. He described fever, chills, night sweats, increasing fatigue and body aches. He was noted to be an avid runner who had finished within the top five to ten athletes in prior marathons. He stated that despite training intensely, he only finished in 50th place. During this visit, a chest x-ray was obtained which showed no evidence of pneumonia or other abnormalities. He was diagnosed with a minor viral upper respiratory tract infection and over the following week began to notice improvement of his symptoms.
He returned to the office two weeks after the initial visit with worsening fatigue and decreased exercise tolerance. He had become increasingly short of breath after running more than 2 milles. A serologic test for Lyme disease was performed to rule out Lyme carditis after an EKG showed first-degree heart block.
While awaiting the results of the serologic studies the patient had a syncopal episode lasting several seconds and was instructed to go immediately to the emergency department. On review of systems, he denied fever, chills, lightheadedness, chest pain, palpitations, shortness of breath, diaphoresis, nausea, vomiting, abdominal pain, rashes, arthralgias, myalgias or trauma. First-degree heart block was again noted on an EKG. The patient was discharged with an appointment to see cardiology as an outpatient. Two days later, the patient had a similar syncopal event during his cardiology appointment. An immediate EKG showed a 2:1 heart block and the patient was admitted to the coronary care unit for further observation and workup.
His past medical history was significant for glaucoma, for which he took xalatan eye drops. He denied any additional medications or drug allergies. His family history was significant for a father who died from chronic lymphocytic lymphoma.
PHYSICAL EXAM
Physical examination revealed a temperature of 99° F, blood pressure of 159/76 mm Hg, pulse range of 38 to 45 beats per minute, respiratory rate of 18 breaths per minute, oxygen saturation of 100% on room air, weight of 173 lbs and height of 6 feet. The patient was in no acute distress. His skin was warm and dry. The oral mucosa was moist and his throat was without erythema or lesions. His neck was supple without lymphadenopathy or nuchal rigidity. The lung fields were clear to auscultation bilaterally. Cardiac exam was significant for bradycardia without murmurs, rubs or gallops. The abdominal exam was unremarkable. Extremities revealed full range of motion, no pedal edema and good peripheral pulses. No deficits were noted on the neurologic exam.
Differential Diagnosis
- Lyme carditis
- Ischemic cardiomyopathy
- Viral myocarditis
- Idiopathic cardiomyopathy
- Cardiac valvular disease
- Sick sinus syndrome
Laboratory Data:
Table 1. Admission Laboratory Data.*
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An electrocardiogram (EKG) showed sinus bradycardia at 37 beats per minute with a 2:1 Mobitz heart block. Chest X-ray showed no active disease.
Serologic studies done at the primary care physician’s office were negative for Lyme disease.
HOSPITAL COURSE
The patient was empirically treated with intravenous ceftriaxone for suspicion of Lyme disease-induced heart block. Outpatient Lyme serologies were negative. An enzyme-liked immunosorbent assay (ELISA) and Western Blot test for Lyme disease were resent due to the high false negative rate associated with Lyme serolgies performed early in the course of the illness. In addition, viral serologies for cytomegalovirus (CMV), Ebstein Barr virus (EBV), Coxsackie virus, and Parvovirus were also performed. An echocardiogram showed mild left atrial dilation, trace tricuspid regurgitation and a normal ejection fraction. The patient refused to complete an attempted stress echo secondary to emotional distress. A stress EKG showed first-degree heart block with intermittent 2:1 Mobitz heart block and a right bundle branch block. No ischemic changes were noted. A MRI of the heart showed mild dilation of the left atrium, similar to that seen on the echo.
Hematology consultation attributed the patient’s anemia to be a result of chronic disease due to an underlying inflammatory process. The patient’s iron studies, folate, vitamin B12, direct Coombs test, Parvovirus, EBV IgM, CMV IgM, erythropoietin level and peripheral smear were all within normal limits. The second set of Lyme ELISA and western blot tests were positive and the diagnosis of Lyme carditis was confirmed.
DISCUSSION
Lyme disease is caused by the spirochete Borrelia burgdorferi and transmitted by the Ixodes tick. It is endemic to the Northeast, Wisconsin, Minnesota, California, Oregon and some parts of Western Europe. Several days to weeks after initial infection most patients will develop a febrile illness characterized by headaches, nuchal rigidity, myalgias, arthralgias, and erythema chronicum migrans. This characteristic rash is also known as the “target rash”, occurs at the site of the tick bite and is associated with regional lymphadanopathy.
The diagnosis of Lyme disease is clinical, with confirmation by serologic studies. Interestingly, serologic studies may be negative early in the course of the disease. Despite negative serologic studies, Lyme carditis should be highly suspected in any male who presents with unexplained atrioventricular block. A positive Lyme titer may represent either recent or past exposure. A positive titer does not confirm the diagnosis of Lyme disease because it may be positive in patients with inactive disease due to past exposure. The CDC recommends a two-step method for the diagnosis of Lyme disease because the ELISA test has a high rate of false positive values. Patients are initially screened using ELISA and positive results are confirmed by Western Blot.
Lyme carditis is a complication of disseminated (stage 2) Lyme disease. Cardiac involvement may be manifested as an atrioventricular block, myopericarditis or cardiomegaly. An AV block, as seen in this case, is the most common manifestation of Lyme carditis. Hospitalization with continuous telemetry monitoring is recommended for patients who present with second or third degree AV block, or those who present with first degree AV block with the PR interval exceeding 0.30 seconds. Most patients with Lyme carditis treated early with appropriate IV antibiotics have an excellent prognosis. The antibiotic treatments include either 2 grams of ceftriaxone IV daily, 2 grams of cefotaxime IV three times daily or 5 million units of penicillin G four times daily.
Patients who do not respond to IV antibiotics and have persistent AV block may require permanent pacemaker placement. Lyme carditis is a rare cause of AV Block, but one with an excellent prognosis if the signs and symptoms are recognized early and the proper treatment is initiated without delay.
REFERENCES
- AcAlister, HF, Klementowiez, PT, Andrews, C, Fisher, JD, Feld, M, Furman, S. Lyme Carditis: An Important Cause of Reversible Heart Block. Annals of Internal Medicine 1989;110(5): 339-345.
- Andreoli, TE, Carpenter, CCJ, Griggs, RC, Loscalzo, J. Lyme Disease. Cecil Essentials of Medicine 6th Edition 2004; 828.
- Steere, C. Medical Progress: Lyme Disease. New England Journal of Medicine 2001;345(2): 115-125.