Isolated Fascicular Abducens Nerve Palsy and Lyme Disease

A patient with Lyme disease developed an isolated sixth nerve palsy at the end of a 1 month course of oral antibiotics. Magnetic resonance imaging disclosed high-signal abnormality at the left pontomedullary junction, implicating involvement of the distal sixth nerve fascicle. Although facial numbness ensued during a subsequent course of intravenous antibiotics, corticosteroid therapy was associated with prompt improvement of neurologic signs, suggesting an immunologic mechanism for the central nervous system dysfunction.