Dizziness red flags

Red flags indicating serious underlying causes of dizziness include:

• Sudden-onset dizziness accompanied by focal neurological deficits such as vertical or rotatory nystagmus, new-onset unsteadiness, or new-onset deafness, which may indicate posterior circulation stroke and require immediate referral ¹.
• Sudden-onset acute vestibular syndrome (vertigo, nausea or vomiting, and gait unsteadiness) with abnormal HINTS test findings (normal head impulse test, direction-changing nystagmus, or skew deviation) suggesting stroke, necessitating urgent neuroimaging and referral ¹.
• Isolated, persistent vertigo lasting more than 24 hours with hyperacute onset (seconds), normal head impulse test, new headache, new unilateral deafness, cranial nerve weakness or sensory loss, limb weakness or sensory loss, or severe ataxia, all of which are red flags for central causes such as brainstem stroke and require urgent brain imaging and specialist referral ².
• Very sudden onset of vertigo (within seconds) that is persistent and not provoked by positional change ².
• New headache, especially occipital or worsening headaches, associated with dizziness ².
• Acute unilateral deafness without typical features of Meniere's disease ².
• Central neurological symptoms or signs such as gait disturbance, truncal ataxia, purely vertical or torsional nystagmus ².
• Severe nausea and vomiting preventing oral fluid intake or symptomatic drug treatment, which may require hospital admission ².