To describe multifocal acute ischemic strokes as an unusual presentation of Lyme disease.

Lyme disease is the most common tick-borne infection in North America and diverse neurological complications are common (Lyme Neuroborreliosis, (LNB)). Stroke is an uncommon consequence of Lyme disease, particularly when seen as a small vessel vasculitis, and has rarely been illustrated in detail.

We report a case of a 76-year-old woman who presented to an outside hospital with left complete facial-nerve palsy and multiple large rounded areas of erythematous rash. She was started on oral doxycycline antibiotic treatment pending Lyme serology. Non-contrast magnetic resonance imaging (MRI) of the head revealed small acute ischemic infarcts in multiple vascular territories. She was transferred to our institution for evaluation of possible embolic stroke. She had no other neurological deficits. No vasculitis or stenotic lesions suggesting intracranial vasculopathy were noted on computerized tomography angiogram of the head and neck. A comprehensive systemic vasculitis work-up was unremarkable. Stroke work-up including transesophageal-echocardiogram (TEE) and cardiac monitoring were negative for any cardiac or arterial source of embolism for her strokes. Contrast-enhanced MRI of the head on day-3 of the admission showed enhancement of the evolving infarcts, but no new lesions or meningeal enhancement. Serological and cerebrospinal fluid examination confirmed LNB. Treatment with intravenous Ceftriaxone led to resolution of her symptoms by day-7 of the 2-week course of antibiotics. 

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The radiographic and clinical pattern of multiple small cerebral infarcts in our patient is consistent with small vessel vasculitis due to LNB. LNB should be suspected in patients with stroke of undetermined source, especially in those patients possibly exposed to ticks in endemic areas. Early treatment was effective in our patient.