What imaging studies are recommended for suspected Lyme disease?

Imaging Studies for Suspected Lyme Disease

Clinicians should not routinely perform diagnostic imaging for patients with suspected Lyme disease. 1

Primary Diagnostic Approach

The diagnosis of Lyme disease is fundamentally clinical and serologic—not radiographic. 1

• Imaging is not indicated for routine evaluation of suspected Lyme disease, as the diagnosis relies primarily on clinical findings (exposure history, characteristic signs/symptoms) and two-tiered serologic testing. 1
• The American Academy of Otolaryngology-Head and Neck Surgery explicitly recommends against routine diagnostic imaging for new-onset manifestations like Bell's palsy in the context of possible Lyme disease. 1
• This recommendation is based on avoiding unnecessary radiation exposure, preventing false-positive workups, and reducing costs (imaging can range from hundreds to thousands of dollars). 1

When Imaging May Be Considered

While imaging is not part of standard Lyme disease diagnosis, there are specific clinical scenarios where imaging serves to rule out alternative diagnoses rather than diagnose Lyme disease itself:

Neurologic Presentations

• MRI of the brain/spine may be obtained when evaluating patients with suspected CNS involvement (meningitis, encephalitis, myelitis) to exclude other causes such as stroke, tumors, or demyelinating disease. 1
• However, nonspecific white matter abnormalities on MRI without supporting clinical or epidemiologic features should not prompt Lyme disease testing. 1
• Imaging is used to rule out structural lesions in patients presenting with cranial neuropathies, radiculoneuropathy, or spinal cord inflammation—not to diagnose Lyme disease. 1

Cardiac Presentations

• Electrocardiography (ECG) is essential for suspected Lyme carditis to identify heart block, but this is electrical testing, not imaging per se. 2
• Echocardiography may be warranted when evaluating acute myocarditis/pericarditis of unknown cause in endemic areas, but again, this evaluates cardiac function rather than diagnosing Lyme disease. 2

Musculoskeletal Presentations

• Joint imaging (X-ray, ultrasound, MRI) may be used to evaluate Lyme arthritis severity or exclude other causes of monoarticular/oligoarticular arthritis, but the diagnosis of Lyme arthritis remains clinical and serologic. 1, 2

Critical Pitfalls to Avoid

• Do not order imaging as a screening tool for Lyme disease—this leads to incidental findings, patient anxiety, unnecessary costs, and radiation exposure without diagnostic benefit. 1
• Do not interpret nonspecific imaging findings (such as white matter changes) as evidence of Lyme disease without appropriate clinical context and epidemiologic exposure. 1
• Remember that exposure history is paramount: Even in patients with suggestive clinical findings, those without travel to endemic areas have only a 10% positive predictive value for Lyme serology. 1, 3
• Imaging cannot detect Borrelia burgdorferi or confirm active infection—the organism cannot be reliably visualized or localized through imaging modalities. 1, 4

The Correct Diagnostic Algorithm

1. Assess pretest probability based on exposure history (endemic area residence or travel), season, and characteristic clinical features (erythema migrans, fever, arthralgia, cranial neuropathy). 1, 3

2. For early localized disease with erythema migrans: Diagnose clinically without serologic testing and treat empirically. 1

3. For suspected disseminated disease: Use two-tiered serologic testing (EIA/ELISA followed by Western immunoblot if positive/equivocal). 1, 2

4. Reserve imaging for ruling out alternative diagnoses when the clinical presentation is atypical or when other serious conditions (stroke, tumor, structural cardiac disease) must be excluded. 1