Acute Vertigo With a Normal Head Impulse: When to Worry
A 54-year-old woman presents to the emergency department with 8 hours of severe continuous vertigo, nausea, and vomiting. She cannot walk without support. She has no hearing loss, no headache, and no focal weakness. Blood pressure is 168/94, and she has a history of type 2 diabetes and smoking. On examination, she has spontaneous right-beating horizontal nystagmus that is suppressed with visual fixation. The horizontal head impulse test is normal bilaterally. There is no skew deviation on alternate cover testing. The Dix-Hallpike is negative. She is anxious and asks repeatedly whether this is 'just an inner ear infection' so she can go home.
1. Apply the HINTS examination. What does the combination of findings suggest, and what is the concern?
Read the worked answer
HINTS findings:
- Head Impulse: normal bilaterally - this is the abnormal finding in the acute vestibular syndrome context.
- Nystagmus: direction-fixed horizontal, suppressed by fixation - peripheral-type nystagmus.
- Test of Skew: no skew deviation.
Interpretation: In acute continuous vertigo with nystagmus, a normal head impulse is a red flag for a central cause, most importantly posterior circulation stroke (e.g., cerebellar or brainstem infarction). A peripheral vestibular lesion (vestibular neuritis) typically produces an abnormal head impulse toward the affected side. A normal head impulse in this setting has high sensitivity for central pathology when performed by an experienced examiner.
Caveats:
- HINTS is most reliable when the examiner is trained and when the patient has continuous vertigo with nystagmus.
- It is less reliable in patients with prior vestibular loss or in those with small infarcts.
- Her vascular risk factors (diabetes, smoking, hypertension) raise pretest probability further.
Do not discharge her with a diagnosis of 'inner ear infection' based on nystagmus alone.
2. What is your immediate management and how do you counsel her about the 'inner ear infection' question?
Read the worked answer
Immediate management:
- Do not discharge. Obtain urgent MRI with diffusion-weighted imaging of the brain, which is the most sensitive test for acute posterior circulation stroke. If MRI is unavailable or delayed, involve neurology and consider CT angiography.
- Stroke workup: glucose, electrolytes, ECG, and vascular risk assessment. Keep her NPO pending evaluation.
- Symptom control: antiemetics and cautious vestibular suppressants for short-term comfort only; avoid prolonged use that impedes compensation.
- Safety: bed alarm, assistance with ambulation, fall precautions.
Counseling:
- Acknowledge her concern: 'I understand why this feels like an inner ear problem - the spinning and nausea are the same. But one of the bedside tests that usually points to the inner ear is normal in your case, and that can be a sign of a problem in the brain. That is why I want imaging before you go home.'
- Explain that this is precautionary and that many patients turn out to have a benign cause, but the risk of missing a stroke is too high to ignore.
- Document the HINTS findings, the reasoning, and the shared decision-making conversation.
3. If imaging is initially negative, how do you plan follow-up and rehabilitation?
Read the worked answer
If initial MRI is negative:
- A negative MRI in the first 24–48 hours does not fully exclude stroke, especially small brainstem lesions. Consider repeat imaging or neurology follow-up if symptoms persist or worsen.
- Reassess for other causes: vestibular migraine, medication effect, metabolic derangement, or anxiety-related dizziness once dangerous causes are excluded.
Rehabilitation planning once central cause is excluded or treated:
- If a peripheral cause is later confirmed, begin gaze stabilization and graded balance exercises as symptoms allow.
- If a central cause is identified, coordinate with neurology and tailor rehabilitation to the deficit (e.g., balance training, gait safety, visual dependence reduction).
- Address fall risk at home: remove throw rugs, ensure lighting, and recommend assistance for stairs.
Documentation: record the HINTS results, the rationale for imaging, the counseling provided, and the follow-up plan. If she leaves against advice, document capacity assessment and the risks explained.