Neurosyphilis presenting as ocular motor nerve palsy: two cases and a systematic literature review.

BACKGROUND: Neurosyphilis is an infectious disease of the central nervous system (CNS) caused by Treponema pallidum, which presents with a wide variety of symptoms depending on the affected CNS structures. We describe two cases of neurosyphilis with ocular motor nerve palsy (OMNP) defined as palsy involving cranial nerves (CNs) III, IV, and/or VI, and provide a systemic review of the literature on OMNP associated with neurosyphilis. METHODS: We describe two patients who presented with unilateral palsy of CN III caused by neurosyphilis. We performed a systematic literature search according to PRISMA guidelines, for all patients with neurosyphilis presenting as OMNP and with available clinical data. RESULTS: Case 1 presented with left pupil-involving CN III palsy and enhancement of the left CN III in magnetic resonance imaging (MRI), and recovered completely after intravenous penicillin and steroid. Case 2 showed bilateral optic atrophy and right pupil-involving CN III palsy, and exhibited partial recovery after intravenous penicillin and steroid. We screened 55 studies, and finally included 31 articles involving 43 patients. Unilateral single OMNP involving CN III or VI was the most common type (n = 30, 70%), but unilateral multiple OMNP (n = 5, 12%) and bilateral OMNP (n = 8, 19%) were also present. Overall, CN III (n = 28, 65%) was the most commonly involved ocular motor nerve (OMN), followed by CN VI (n = 22, 51%) and CN IV (n = 4, 8%). About half (n = 20, 47%) of the patients exhibited other neurological deficits concomitantly with OMNP. Brain MRI showed abnormalities that could be responsible for OMNP, including enlargement or enhancement of the OMN itself, T2-weighted hyperintensity within the brainstem, and enhanced masses in the cavernous sinus, pons, and clivus. Most patients achieved complete (n = 21/40, 53%) or partial (n = 13/40, 33%) recovery from OMNP after intravenous or intramuscular penicillin treatment. DISCUSSION: Since early diagnosis and correct treatment of neurosyphilis are essential before irreversible damage occurs in the CNS, clinicians should pay attention to neurosyphilis as a potential cause of OMNP.