Capturing nystagmus in the emergency room: posterior circulation stroke versus acute vestibular neuritis.

OBJECTIVES: To compare acute nystagmus characteristics of posterior circulation stroke (PCS) and acute vestibular neuritis (AVN) in the emergency room (ER) within 24 h of presentation. METHODS: ER-based video-nystagmography (VNG) was conducted, recording ictal nystagmus in 101 patients with PCS (on imaging) and 104 patients with AVN, diagnosed on accepted clinical and vestibular test criteria. RESULTS: Patients with stroke in the brainstem (38/101, affecting midbrain (n = 7), pons (n = 19), and medulla (n = 12)), cerebellum (31/101), both (15/101) or other locations (17/101) were recruited. Common PCS territories included posterior-inferior-cerebellar-artery (41/101), pontine perforators (18/101), multiple-territories (17/101) and anterior-inferior-cerebellar-artery (7/101). In PCS, 44/101 patients had no spontaneous nystagmus. Remaining PCS patients had primary position horizontal (44/101), vertical (8/101) and torsional (5/101) nystagmus. Horizontal nystagmus was 50% ipsiversive and 50% contraversive in lateralised PCS. Most PCS patients with horizontal nystagmus (28/44) had unidirectional "peripheral-appearing" nystagmus. 32/101 of PCS patients had gaze-evoked nystagmus. AVN affected the superior, inferior or both divisions of the vestibular nerve in 55/104, 4/104 and 45/104. Most (102/104) had primary position horizontal nystagmus; none had gaze-evoked nystagmus. Two inferior VN patients had contraversive torsional-downbeat nystagmus. Horizontal nystagmus with SPV ≥ 5.8 °/s separated AVN from PCS with sensitivity and specificity of 91.2% and 83.0%. Absent nystagmus, gaze-evoked nystagmus, and vertical-torsional nystagmus were highly specific for PCS (100%, 100% and 98.1%). CONCLUSION: Nystagmus is often absent in PCS and always present in AVN. Unidirectional 'peripheral-appearing' horizontal nystagmus can be seen in PCS. ER-based VNG nystagmus assessment could provide useful diagnostic information when separating PCS from AVN.

Eye movement disorders in vitamin B12 deficiency: two new cases and a review of the literature.

Eye movement disorders are rarely reported in vitamin B12 deficiency. We describe two cases with eye movement disorder and vitamin B12 deficiency; one with bilateral internuclear ophthalmoplegia and the other with downbeat nystagmus. Both of the patients received replacement therapy but their eye movement disorders did not respond to treatment. We also review the nine previously reported cases.

MRI follow-up of basal ganglia involvement in subacute sclerosing panencephalitis.

A 12-year-old male with subacute sclerosing panencephalitis is presented. Magnetic resonance imaging revealed basal ganglia involvement without white matter changes for several months. Basal ganglia changes are not infrequent in subacute sclerosing panencephalitis, but they tend to appear in advanced clinical stages. Prominent basal ganglia involvement may occur very rarely in subacute sclerosing panencephalitis. In our patient, serial magnetic resonance imaging demonstrated the involvement of white matter after 2 years of magnetic resonance imaging follow-up. In contrast with the neuroradiologic progression, our patient's clinical status remained stable.

A case with cerebral thrombosis receiving tamoxifen treatment.

Cerebral sinus thrombosis (CST) is known to be related to a number of underlying aetiologies including otitis media, trauma, pregnancy, birth control pills, tumours, malnutrition, dehydration, haematologic disorders and malignancy (Fishman, 2000; Raizer and Abbott, 2000). We present the case of a patient with breast cancer receiving the antioestrogen drug tamoxifen who developed CST. A 40-year-old female presented as an emergency with a 10-day history of headache and left sided weakness. On questioning her past medical history included a diagnosis of breast cancer 3 years ago treated by radical mastectomy and tamoxifen 20 mg daily. At the time of admission, neurologic examination revealed a mild left sided hemiparesis and a present Babinksi sign. Non-contrast enhanced tomography was normal. Magnetic resonance imaging (MRI) showed thrombosis in the superior sagittal sinus, right lateral sinus and jugular vein in addition venous infarction in the right temporal lobe was present (Figs 1a and b). Routine haematology and biochemistry was normal. Anticoagulation tests, antithrombin III, protein S and C levels were also found to be normal. She was treated with anticoagulation therapy and her hemiparesis improved within 3 days. Control MRI showed the resorption of the venous infarction and resolution of the thrombosis (Fig. 1c).