Differential diagnosis of acute vestibular syndrome

Acute vestibular syndrome (AVS) occurs, most often, due to vestibular neuritis (VN), although it can be caused by a stroke in posterior circulation system or other damage to structures of posterior cranial fossa (PCF) (multiple sclerosis (MS), etc.). A standard neurological examination cannot accurately confirm or deny stroke, especially if the process is localized in brainstem or cerebellum, what is often inaccessible for neuroimaging during computed tomography. After all, dizziness can be the only symptom of damage to structures of inner ear (peripheral part of vestibular analyzer), as well as brain stem or cerebellum (central part) of vascular, autoimmune­inflammatory genesis, etc. Objective — to improve differential diagnosis of AVS using a 3­step clinical bedside examination of oculomotor function — HINTS test. Materials and methods. 120 patients with symptoms of AVS were examined. The subjective assessment of dizziness was assessed using «Dizziness handicap inventory» questionnaire, Ukrainian version. Patients underwent an otoneurological examination, in particular, evaluation of oculomotor function with assessment of smooth pursuit, test of saccades, assessment of gaze­evoked and spontaneous nystagmus using VideoFrenzel, HINTS test, Fukuda step test, otoscopy, audiometry, brain magnetic resonance imaging (MRI). Statistical data processing (quantitative and qualitative methods of statistical analysis, visual data analysis) was carried out using Statistica 10 and Microsoft Excel (Microsoft Corporation, USA). Results and discussion. Based on results of HINTS test, 102 (85 %) patients were diagnosed with acute unilateral vestibulopathy (AUVP)/VN. HINTS indicated damage to central nervous system in 13 (10.8 %) persons. BPPV was diagnosed in 4 (3.3 %) patients as a result of canalolithiasis of lateral semicircular canal (nystagmus was pseudospontaneous). One patient (0.8 %) was diagnosed with Ménière’s disease. Among 102 patients with AUVP according to HINTS test after performing brain MRI 8 (7.8 %) people were diagnosed with CNS pathology: in 3 (2.9 %) patients — ischemic stroke in brain stem, in 2 (2 %) of them — ischemic stroke in cerebellum and in 3 (2.9 %) of patients — MS. Among 13 patients with signs of central AVS according to HINTS, in 3 (23.1 %) persons h­HIT was normal, which indicated central cause, however, according to brain MRI, no CNS pathology was confirmed. Conclusions. After differential diagnosis of AVS using otoneurological examination, CNS lesions were confirmed in only 15 % of cases, in comparison to initial suspicion of a stroke in 77.5 % of cases assessed by a standard neurological examination. Suspicion of AUVP/VN was confirmed in only 6.3% of patients. As a result of the obtained data, we recommend the introduction of HINTS test into the national standards of differential diagnosis of AVS. HINTS test showed a high sensitivity for CNS damage — 92.2 %. However, the search for additional specific markers of central AVS in cases of pseudoneuritis according to the HINTS test remains relevant.