To differentiate between peripheral and central causes of dizziness in adults, key clinical features include the nature of the nystagmus, the results of the head impulse test, the presence of other neurological symptoms or signs, and the characteristics of the dizziness itself NICE CKS,NICE NG127.
- Nystagmus: Purely vertical or torsional nystagmus, or direction-changing nystagmus, are red flags indicative of a central cause, such as a brainstem stroke NICE CKS,NICE NG127.
- Head Impulse Test (HINTS): In adults with sudden-onset acute vestibular syndrome (vertigo, nausea/vomiting, gait unsteadiness), a normal head impulse test suggests a central cause (e.g., stroke) and warrants immediate neuroimaging NICE CKS,NICE NG127. A negative HINTS test makes a diagnosis of stroke very unlikely NICE NG127.
- Associated Neurological Symptoms/Signs: The presence of central neurological symptoms or signs strongly suggests a central cause NICE CKS. These include new type of headache (especially occipital), gait disturbance, truncal ataxia, new-onset unsteadiness, new-onset unilateral deafness, cranial nerve weakness or sensory loss, or limb weakness or sensory loss NICE CKS,NICE NG127. Dizziness without imbalance or other focal neurological deficit is unlikely to indicate a serious neurological condition NICE NG127.
- Onset and Persistence: Very sudden onset of vertigo (within seconds) that is not provoked by positional change and is persistent, or isolated persistent vertigo lasting over 24 hours with hyperacute onset, are red flags for a central cause NICE CKS. Transient rotational vertigo on head movement, however, is characteristic of a peripheral cause like benign paroxysmal positional vertigo (BPPV) NICE NG127.
- Ataxia: Severe ataxia is a red flag for a central cause NICE CKS.
- Altered Consciousness: Recurrent fixed-pattern dizziness associated with alteration of consciousness may indicate epilepsy NICE NG127.
Common peripheral causes of dizziness include benign paroxysmal positional vertigo (BPPV), Meniere's disease, and vestibular neuronitis NICE CKS. Vestibular migraine is another possibility, characterized by episodes of dizziness lasting between 5 minutes and 72 hours with a history of recurrent headache NICE NG127. If a central cause is suspected, urgent admission to hospital or referral to a balance specialist (e.g., neurologist or audiovestibular physician) is recommended, with urgency depending on symptom severity and suspected diagnosis NICE CKS.