Orbital myositis in Lyme disease is an unusual but recognized manifestation of Borrelia infection. Two case reports demonstrate how this condition presents and responds to antibiotic treatment.

Orbital myositis is typically caused by systemic diseases such as Graves’ disease or hematological disorders like lymphomas. In these cases, myositis is often bilateral. It has also been reported as a rare manifestation of Lyme disease.

In these two cases, myositis was confirmed by MRI findings.

Patient 1: 68-Year-Old Woman with Recurrent Episodes

The 68-year-old patient experienced acute and recurrent episodes lasting 2 to 4 weeks, occurring 2 to 4 times each year. She presented with right orbital swelling and pain.

Each episode resolved spontaneously or with steroids and nonsteroidal anti-inflammatory drugs.

Lyme disease was suspected because the patient lived in a rural area of France highly endemic for Lyme disease. She recalled numerous tick bites and had a history of erythema migrans rash and arthralgia.

Testing for Lyme disease was positive and the woman began treatment with doxycycline. Within 3 weeks, her symptoms had completely resolved.

Patient 2: 13-Year-Old Girl with Unilateral Swelling

The 13-year-old adolescent complained of unilateral orbital swelling complicated by exophthalmos and horizontal diplopia.

MRI showed a hyperintense signal of the right inferior and medial rectus muscles, confirming orbital myositis.

The patient lived in an area endemic for Lyme disease and had a recent tick bite followed by an erythema migrans rash.

Lyme disease testing was positive and she was treated successfully with 4 weeks of doxycycline. Resolution of ocular symptoms and a decrease in MRI signal intensity were observed within 1 month.

Clinical Recognition and Diagnosis

Orbital myositis is an unusual manifestation of Lyme disease, although it is likely underdiagnosed.

Unexplained muscle swelling occurring in a patient who has had a rash or recent history of a tick bite in an endemic area for Lyme disease should prompt consideration of this diagnosis.

Both patients in these case reports responded well to antibiotic therapy, with complete or near-complete resolution of symptoms within weeks of starting treatment.

Frequently Asked Questions

What is orbital myositis in Lyme disease?

Orbital myositis in Lyme disease is inflammation of the extraocular muscles caused by Borrelia burgdorferi infection. It presents with eye swelling, pain, and sometimes double vision.

How is orbital myositis diagnosed?

Diagnosis is confirmed by MRI showing hyperintense signal in the extraocular muscles, combined with positive Lyme disease testing and clinical history of tick exposure or erythema migrans rash.

Is orbital myositis from Lyme disease bilateral or unilateral?

Lyme-associated orbital myositis is typically unilateral, unlike systemic causes which are often bilateral.

How is orbital myositis from Lyme disease treated?

Treatment involves antibiotics such as doxycycline for 3-4 weeks. Some patients may receive corticosteroids initially for symptom relief before Lyme diagnosis is confirmed.

Do symptoms resolve with treatment?

Yes. Both case reports demonstrated complete resolution of ocular symptoms within 3-4 weeks of antibiotic therapy, with MRI confirmation of improvement.

Clinical Takeaway

Orbital myositis should be considered in patients with unexplained eye muscle swelling, especially in endemic areas or with history of tick bite or erythema migrans rash. This rare manifestation of Lyme disease is likely underdiagnosed and responds well to appropriate antibiotic therapy.