P115. Painful mydriasis as the only clinical sign of an ipsilateral midbrain abscess

Abstract

History A 39-year-old man noted increasing right frontal and right retroorbital pain. After 3 days, he also noted blurred vison in the right eye. On clinical examination, he had a mydriatic right pupil with diminished light reaction but otherwise normal findings including eye movements examination (and direct-current electro-oculography). Findings Masseter reflex testing disclosed an increased latency on the right side and was interpreted in favor of an ipsilateral mesencephalic lesion. MRI documented an abscess in the left ventral midbrain involving the region of the distal intra-mesencephalic segment of the 3rd nerve. Cerebrospinal fluid analysis revealed 185 leucocytes/ μ l, mildly elevated total protein (536 g/l), and normal glucose and lactate levels. There was no serological evidence for neuroborreliosis, neurolues, brucellosis, leptospirosis, echinococcosis, or fungal infections. Transesophageal echocardiography and dental and otolaryngological examinations were normal. Treatment He was treated with a combination of ceftriaxone (2 × 2 g/d) plus flucloxacillin (4 × 2 g/d) plus metronidazole (3 × 500 mg/d) for 6 weeks, and for another 6 weeks with cotrimoxazole (800 mg sulfamethoxazole + 160 mg trimethoprim twice daily). During the first 2 weeks antibiotic treatment was accompanied by dexamethasone (initial bolus of 40 mg i.v. followed by 4 × 8 mg/d, which was slowly tapered within 2 weeks). Clinical course Complete clinical recovery occurred within 2 weeks and CSF was normal after 15 days (4 leukoctes/ μ l, total protein: 228 g/l) Conclusion Painful unilateral mydriais may be the only clinical sign of an ipsilateral midbrain lesion.