Acute Vestibular Neuronitis

Accepted definition/diagnostic criteria Acute vestibular neuronitis, also known as vestibular neuritis, is a peripheral vestibular disorder characterised by a sudden onset of severe, persistent vertigo, nausea and vomiting, without hearing loss or tinnitus. The primary pathology involves inflammation of the vestibular nerve. Diagnosis is primarily clinical, based on the patient’s history and physical examination.

Epidemiology The condition affects adults predominantly, with a peak incidence between ages 30 and 60. It is relatively uncommon, but exact prevalence rates in the UK are not well defined. Vestibular neuronitis is thought to account for 3%-10% of vertigo cases presenting in primary care and up to 7% of cases in specialised vertigo clinics.

Diagnosis
Clinical features: Patients typically present with a sudden onset of intense, debilitating vertigo, which may be accompanied by nausea and vomiting. Unlike Menière’s disease, there is no associated hearing loss. The vertigo is often worsened by head movement and may be accompanied by nystagmus. A key feature in history taking is the absence of neurological symptoms such as dysarthria or limb ataxia, which may indicate a central cause of vertigo.

Investigations: Investigations are usually not necessary for typical cases but can be considered to rule out differential diagnoses. The Dix-Hallpike test may be used to exclude benign paroxysmal positional vertigo (BPPV). In some cases, particularly if a central cause of vertigo is suspected, MRI scans may be indicated.

Treatment The initial management focuses on symptom relief. Antihistamines like cinnarizine or prochlorperazine can be used to alleviate nausea and vertigo in the acute phase. Steroids are not routinely recommended, and the role of antiviral agents remains uncertain. Once the acute phase resolves, vestibular rehabilitation exercises are recommended to hasten functional recovery. These exercises involve specific head and body movements that help in vestibular compensation.

Prognosis The prognosis for acute vestibular neuronitis is generally good. Most patients experience a substantial reduction in symptoms within the first few days, and complete recovery is seen in approximately 70% of cases within several weeks to months. However, some patients may have residual symptoms like unsteadiness and dizziness for a longer duration. Persistent symptoms should prompt reassessment for alternative diagnoses or the development of secondary complications like BPPV.