Negative Lyme Test Case: When Diagnosis Is Missed in a 75-Year-Old Patient
Initial test was negative
Symptoms rapidly worsened
Diagnosis required deeper testing
Treatment led to rapid recovery
How often is Lyme disease dismissed after a negative test? This case of a 75-year-old man highlights how a negative Lyme disease test can delay diagnosis—even when symptoms are severe. :contentReference[oaicite:0]{index=0}
Initial Presentation
The patient, a 75-year-old man, presented with:
- Unsteady gait
- Mild anemia
- Low platelet count
He was initially evaluated and sent home.
Rapid Clinical Deterioration
Four days later, he returned with severe symptoms:
- Fever up to 105°F
- Rigors and chills
- Diffuse muscle pain
- Weakness and confusion
- Loss of balance
His condition worsened quickly.
He developed:
- Tachycardia (>200 bpm)
- Low blood pressure
- Encephalopathy
A Negative Lyme Disease Test
Doctors initially considered Lyme disease—but the screening test was negative.
No Western blot was ordered at that time.
He was treated empirically with broad-spectrum antibiotics.
For more, see Lyme test accuracy.
Diagnosis Confirmed With Further Testing
As his condition worsened, additional testing revealed:
- Positive Lyme IgM and IgG
- Positive Western blot
- Positive Babesia microti antibodies
A spinal tap confirmed Lyme disease:
- 3/3 IgM bands positive
- 9/10 IgG bands positive
The patient was diagnosed with Lyme neuroborreliosis.
For more, see neurologic Lyme disease.
Treatment and Rapid Improvement
The patient was treated with:
- Doxycycline for 21 days
Within 48 hours, his cognitive function and gait returned to normal.
Notably, Babesia was identified but not treated.
For coinfections, see Lyme coinfections.
Why This Case Matters
This case highlights key clinical lessons:
- Lyme disease may present without classic symptoms
- Screening tests can be negative early or late
- Failure to follow up with confirmatory testing can delay diagnosis
- Neurologic Lyme disease can occur without meningitis
- Coinfections may complicate the clinical picture
Relying on a single negative test may lead to missed or delayed diagnosis.
Clinical Questions Raised
- How often is Lyme disease dismissed after a negative test?
- Should Babesia have been treated given the patient’s risk profile?
- What are the long-term outcomes in similar cases?
Clinical Takeaway
A negative Lyme disease test does not exclude the diagnosis.
Patients with persistent or severe symptoms should undergo further evaluation.
Early recognition and appropriate testing can prevent life-threatening complications.
Related Reading
References
- Lamichhane J et al. Case Rep Infect Dis. 2018.
- Logigian EL et al. N Engl J Med. 1990.
Dr. Daniel Cameron, MD, MPH
Lyme disease clinician with over 30 years of experience and past president of ILADS.
Symptoms • Testing • Coinfections • Recovery • Pediatric • Prevention
