Case reports: Orbital myositis due to Lyme disease

Orbital myositis is typically caused by systemic disease, such as Grave’s disease, or haematological disorders like lymphomas, the authors explain. In these cases, myositis is often bilateral. It has been reported, as well, as a rare manifestation of Lyme disease.

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

Patient #1: 68-year-old female

“The 68-year-old patient had acute and recurrent episodes (lasting from 2 to 4 weeks, 2 to 4 times each year) of right orbital swelling and pain,” the authors wrote.

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

Lyme disease was suspected since the patient was living in a rural area of France, highly endemic for Lyme disease, and she recalled having numerous tick bites and had a history of an erythema migrans rash and arthralgia.

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

“We reported the cases of two patients who presented with orbital myositis caused by Borrelia infection.”

Patient #2: 13-year-old female

The 13-year-old adolescent complained about unilateral orbital swelling complicated with exophthalmia and horizontal diplopia.

“MRI showed a hyperintense signal of right inferior and medial rectus muscles,” the authors wrote.

The woman was living 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.

The authors reported, “a resolution of ocular symptoms and a decrease of the MRI signal intensity were observed within 1 month.”

The authors conclude:

• “Orbital myositis is an unusual manifestation of Lyme disease, although it is likely that the condition is underdiagnosed.”
• “Unexplained muscle swelling occurring in a patient who has had a rash or a recent history of a tick bite in an endemic area for Lyme disease should prompt consideration of this diagnosis.”