Ankle arthritis in a 6-year-old boy after a tick bite - a case report
Related Experiment Video
Updated: Jun 1, 2026
A Model for Experimental Exposure of Humans to Larval Ixodes scapularis Ticks
Published on: December 1, 2023
Per-Henrik Randsborg1, Carl-Erik Naess
1Department of Orthopedic Surgery, Akershus University Hospital, 1478 Lørenskog, Norway.
Background:
Monoarthritis of the ankle is a rare condition in children, and is most often caused by a bacterial infection. Lyme disease is endemic in southern Scandinavia, and diagnosis remains a challenge. The clinical presentation of Lyme disease varies greatly, and often with considerable delay between exposure and presentation.
Case Presentation:
We report a case of ankle arthritis in a boy who presented one year earlier with a tick bite on the dorsum of the foot. He was suboptimally treated with oral antibiotics for one week, and developed in the following months a painless limp. Radiographs revealed a severe arthritis of the right ankle joint with necrosis of the talus and deformation of the talocrural and subtalar joints. There was no history of malaise, fever or other systemic symptoms. He remains seronegative for antibodies against B. burgdorferi.
Conclusions:
The suboptimal oral antibiotic treatment may have hindered the antibody production against B burgdorferi, while not being therapeutic, resulting in severe ankle arthritis due to seronegative Lyme disease.
Insights
Seronegative Lyme disease can cause severe ankle arthritis in children, even without typical symptoms. Suboptimal antibiotic treatment may prevent antibody detection, complicating diagnosis of this rare condition.
Area of Science:
- Pediatric infectious diseases
- Rheumatology
- Medical diagnostics
Background:
- Monoarthritis of the ankle is uncommon in children, frequently stemming from bacterial infections.
- Lyme disease, endemic in southern Scandinavia, presents diagnostic challenges due to varied clinical manifestations and delayed presentation.
- Early diagnosis of Lyme disease is crucial, yet often complicated by atypical presentations.
Observation:
- A pediatric case of severe ankle arthritis with talar necrosis and joint deformation is presented.
- The patient had a history of a tick bite and suboptimal oral antibiotic treatment one year prior.
- Despite severe joint damage, the patient remained seronegative for antibodies against Borrelia burgdorferi.
Findings:
- Suboptimal antibiotic therapy may have inhibited antibody production against Borrelia burgdorferi.
- This inhibition, coupled with insufficient treatment, led to severe, seronegative Lyme disease presenting as ankle arthritis.
- The case highlights the potential for Lyme disease to manifest with severe joint destruction without serological confirmation.
Implications:
- This case underscores the importance of considering Lyme disease in pediatric ankle arthritis, even in seronegative individuals.
- Diagnostic challenges in Lyme disease necessitate a comprehensive approach beyond serology, especially after incomplete antibiotic treatment.
- Further research is needed to understand the impact of suboptimal antibiotic treatment on Lyme disease pathogenesis and serological markers in pediatric populations.
Related Concept Videos
01:26Rocky Mountain Spotted Fever
01:25Arboviral Encephalitis