Lyme myocarditis in adolescents frequently presents with respiratory and gastrointestinal symptoms rather than typical cardiac complaints. A 15-year-old girl with severe epigastric pain was initially worked up for gallbladder disease before Lyme myocarditis was discovered. Her troponin was 50 times the threshold for heart attack, yet chest pain wasn’t her primary complaint. This case demonstrates why clinicians must maintain high suspicion for cardiac Lyme disease even when symptoms seem non-cardiac.

Why Lyme Myocarditis Recognition Matters

In 2013, the Centers for Disease Control and Prevention (CDC) described three cases of sudden deaths associated with Lyme-induced myocarditis. “During November 2012 and July 2013, one woman and two men (ranging in age from 26 to 38 years) from high-incidence Lyme disease states experienced sudden cardiac death and, on postmortem examination, were found to have evidence of Lyme carditis.”

These weren’t elderly patients with long histories of heart disease. These were young adults — ages 26, 30s, late 30s — who died suddenly from unrecognized Lyme carditis. The autopsies revealed the truth too late.

This context makes recognizing atypical presentations of Lyme myocarditis literally life-saving.

Case Report: 15-Year-Old With Atypical Presentation

In this week’s journal of Pediatric Emergency Care, researchers offer insight into how Lyme myocarditis might present in a patient as they describe the case of a previously healthy adolescent diagnosed with the disease. The patient lived in a Lyme-endemic region but did not recall a tick bite.

A 15-year-old African-American girl was hospitalized after a three-day history of intermittent retrosternal and epigastric pain. The pain was described as “gnawing” and “twisting” without radiation in the sternal and right upper quadrant area. The pain was 9 on a 1 to 10 scale. There was no evidence of costochondritis.

The pain location and quality suggested gastrointestinal pathology, not cardiac disease. “Retrosternal and epigastric” means behind the breastbone and in the upper abdomen — locations associated with stomach, esophagus, or gallbladder problems, not typically with heart disease.

Pain severity of 9/10 indicated this wasn’t mild discomfort. This was severe, debilitating pain that brought her to the hospital.

Initial Workup: Gallbladder Disease Suspected

Cholecystitis was considered. She presented with mild abnormal elevations of her liver function tests, focal dilation of the common bile duct, gallbladder thickening by ultrasound, and a positive Murphy sign.

Murphy’s sign is a test for gallbladder disease in which the patient is asked to inhale while the examiner’s fingers are pressed under the right rib cage. If the patient stops breathing or is in pain as the patient breaths out, the gallbladder is inflamed.

The pediatric surgeon concluded the exam was consistent with cholelithiasis but not acute cholecystitis.

Everything pointed toward gallbladder disease: abnormal liver tests, bile duct dilation, gallbladder wall thickening, positive Murphy sign. The workup was logical. But it was wrong.

Myocarditis Diagnosed: Severe Cardiac Damage

The patient was hospitalized with a presumptive diagnosis of myocarditis. Her initial electrocardiography (EKG) “indicated normal sinus rhythm but revealed low voltages throughout all leads, widened QRS complex, right axis deviation, and nonspecific intraventricular conduction block.”

Fishe also noted that the “Troponin-I was markedly elevated at 15.81 ng/mL indicating myocardial injury (hospital laboratory criterion for acute myocardial infarction >0.3 ng/mL).”

Let’s put that troponin level in perspective. The threshold for diagnosing heart attack is >0.3. Her troponin was 15.81 — more than 50 times the heart attack threshold. This indicated massive myocardial damage.

Additionally, “A bedside echocardiogram revealed moderately diminished left ventricular systolic shortening (ejection fraction, 37%-40%) and a trivial pericardial effusion.”

Normal ejection fraction is 55-70%. Hers was 37-40%, meaning her heart was pumping less than two-thirds of normal capacity. The heart muscle was failing from inflammatory damage.

Lyme Disease Considered on Day 1

Lyme disease was considered on the first day during empiric treatment with 1 g/kg intravenous immune globulin (IVIG). She developed second-degree atrioventricular block (Mobitz type 2) and hypotension.

The clinical team’s decision to consider Lyme disease early was critical. Despite the atypical presentation (primarily GI symptoms), they recognized she was from an endemic area with unexplained myocarditis.

The development of second-degree heart block (Mobitz Type 2) confirmed cardiac electrical involvement, not just muscle inflammation. Her blood pressure dropped (hypotension), indicating cardiovascular collapse was imminent.

Empiric Antibiotics Started

Lyme disease tests were ordered, and she was empirically started on doxycycline. She was treated with milrinone infusion for afterload reduction and intravenous furosemide for pulmonary edema.

Empiric doxycycline meant treatment before diagnostic confirmation — the correct approach when Lyme carditis is suspected. Waiting for test results could be fatal.

Milrinone is an inotrope that helps the failing heart pump more effectively. Furosemide (Lasix) removes fluid from lungs when heart failure causes pulmonary edema. These interventions supported her cardiovascular system while antibiotics addressed the underlying infection.

Rapid Improvement With Treatment

Her EKG changed to first-degree heart block by day 2 and resolved completely on hospital day 3. The authors noted that a Cochrane review found insufficient evidence to support IVIG use in acute myocarditis.

The progression from second-degree block to first-degree to normal rhythm within three days demonstrates how rapidly Lyme myocarditis responds to antibiotics. Once spirochetes were being killed, cardiac inflammation subsided and electrical conduction recovered.

The IVIG (intravenous immunoglobulin) likely wasn’t helpful, as the authors note evidence doesn’t support its use. The improvement came from doxycycline.

Diagnosis Confirmed

Her Lyme disease was subsequently confirmed with serologic tests. Lyme enzyme-linked immunosorbent assay (ELISA) and immunoglobulin M (IgM) of 0.87 (reference range, 0.00-0.79) were positive.

The positive IgM indicates recent or current infection. The mildly elevated ELISA (0.87 vs. cutoff of 0.79) shows early antibody response, consistent with acute infection rather than chronic disease.

The patient recovered and was discharged home on hospital day 7 on oral furosemide, enalapril, and doxycycline, according to Fishe and colleagues.

Seven days from admission to discharge. Seven days from troponin 50x heart attack threshold and ejection fraction of 37% to stable enough for home. The reversibility of Lyme myocarditis, when treated appropriately, is remarkable.

Critical Lessons for Clinicians

“It is important to explain all results that are found as part of the diagnostic work-up,” the authors conclude. Furthermore, “In patients with Lyme disease who complain of cardiopulmonary symptoms, clinicians should have a low threshold for obtaining an EKG to evaluate for Lyme carditis.”

And, note that in “children and adolescents, respiratory and gastrointestinal complaints, with or without chest pain, are the most frequent presenting symptoms.”

This last point deserves emphasis. Pediatric Lyme myocarditis doesn’t typically present as “chest pain.” It presents as:

• Respiratory symptoms: Shortness of breath, difficulty breathing
• Gastrointestinal symptoms: Abdominal pain, nausea, vomiting
• Chest pain may be absent

This 15-year-old had primarily epigastric (upper abdominal) pain, leading to gallbladder workup. Her chest discomfort was secondary. Yet her troponin was astronomical and her heart was failing.

When Lyme Testing Is Negative

The case of a young man who died from undiagnosed Lyme carditis is discussed in another All Things Lyme blog, Relying on a Negative Lyme Disease Test Can Prove Deadly.

Negative Lyme tests don’t rule out Lyme carditis, especially in acute infection when antibodies haven’t fully developed. Clinical suspicion must override negative serology when presentation is consistent.

Clinical Perspective

This case illustrates a diagnostic trap: young patients with Lyme myocarditis often don’t present with “typical” cardiac symptoms. This 15-year-old’s primary complaint was severe upper abdominal pain. The gallbladder workup was reasonable given her symptoms, ultrasound findings, and physical exam.

But someone thought to check an EKG. That decision saved her life. The EKG showed conduction abnormalities. The troponin was checked and came back catastrophically elevated. The echo showed failing heart. Only then was the cardiac diagnosis made.

If the team had fixated on the gallbladder findings and not obtained cardiac workup, she might have been discharged with presumed cholecystitis. Days later, she could have died suddenly from complete heart block or cardiac arrest — added to the CDC’s list of Lyme carditis deaths.

The emphasis that respiratory and GI symptoms are the “most frequent presenting symptoms” in pediatric Lyme carditis challenges assumptions. When we think “heart disease,” we think chest pain. But kids with Lyme myocarditis more often complain of breathing difficulty or stomach pain.

This girl’s troponin of 15.81 — more than 50 times the heart attack threshold — with ejection fraction of 37-40% indicates she was in cardiogenic shock. Her heart muscle was severely inflamed and failing. Yet her primary complaint was abdominal pain.

The rapid recovery is equally striking. From near-death on admission to hospital discharge on Day 7. From troponin >15 and EF 37% to stable on oral medications. From second-degree heart block to normal rhythm in three days. Lyme myocarditis, when recognized and treated, is reversible.

The authors’ recommendation for “low threshold for obtaining an EKG” in patients with known or suspected Lyme disease is practical. EKGs are cheap, non-invasive, and potentially life-saving. Any Lyme patient with respiratory or cardiac symptoms deserves an EKG.

Frequently Asked Questions

Can Lyme myocarditis present as stomach pain?

Yes. In children and adolescents, gastrointestinal complaints are among the “most frequent presenting symptoms” of Lyme myocarditis, with or without chest pain. This 15-year-old’s primary complaint was severe epigastric pain, initially attributed to gallbladder disease.

How high can troponin get in Lyme myocarditis?

This patient’s troponin was 15.81 ng/mL — more than 50 times the threshold for heart attack (>0.3). Lyme myocarditis can cause severe myocardial damage with markedly elevated cardiac biomarkers despite the reversible nature of the condition.

Can heart failure from Lyme disease be reversed?

Yes. This patient had ejection fraction of 37-40% (moderately reduced) on admission but recovered sufficiently for discharge by Day 7. Lyme myocarditis is reversible with appropriate antibiotic treatment.

Should all Lyme disease patients get EKGs?

The authors recommend “low threshold for obtaining an EKG” in Lyme patients with cardiopulmonary symptoms. Any respiratory complaints, chest discomfort, palpitations, shortness of breath, or unexplained GI symptoms warrant EKG evaluation.

Why didn’t this patient have chest pain?

Pediatric Lyme myocarditis often presents atypically. Children and adolescents more commonly have respiratory and gastrointestinal symptoms than classic chest pain. This makes diagnosis more challenging and increases risk of missing cardiac involvement.

Can Lyme myocarditis cause sudden death?

Yes. The CDC documented three sudden cardiac deaths from Lyme myocarditis in young adults ages 26-38. These cases emphasize the importance of recognizing and treating Lyme carditis before fatal arrhythmias or cardiac arrest occur.

How quickly does Lyme myocarditis improve with treatment?

This patient’s heart block progressed from second-degree to first-degree in one day, resolving completely by Day 3. Most cases show improvement within days to weeks of appropriate antibiotics, though full cardiac recovery may take longer.