In a 53‑year‑old man with hypertension and diabetes presenting with sudden vertigo, vomiting, gait ataxia, elevated blood pressure, marked hyperglycemia, and a normal electrocardiogram, what is the differential diagnosis?

Differential Diagnosis

This patient presents with acute vestibular syndrome (AVS) in the setting of multiple vascular risk factors, and posterior circulation stroke—particularly cerebellar or brainstem infarction—must be considered the primary concern until proven otherwise, despite the "otherwise normal" physical examination.

Critical Clinical Context

This 53-year-old man with hypertension and diabetes presents with the classic triad defining AVS: sudden-onset persistent vertigo, vomiting, and gait ataxia 1. The "otherwise normal" physical examination is dangerously misleading—gait ataxia itself represents an abnormal neurologic finding that significantly elevates stroke risk.

Primary Differential (Life-Threatening First)

1. Posterior Circulation Stroke (Cerebellar or Brainstem Infarction) - MOST CRITICAL

• This is the diagnosis you cannot miss. In patients presenting with AVS, the prevalence of cerebrovascular disease approaches 25% and may reach 75% in high vascular risk cohorts like this patient 1
• Critically, 75-80% of patients with AVS related to infarct have NO focal neurologic deficits on standard examination 1
• The presence of gait ataxia is itself a red flag—this is NOT a "normal" examination
• His vascular risk factors (hypertension, diabetes, elevated BP 150/80) place him in the highest-risk category
• Up to 11% of patients with acute persistent vertigo but no other focal neurologic signs have acute infarct on imaging 1

Key Point: The absence of obvious focal deficits does NOT exclude stroke. The guidelines explicitly warn that one-third to two-thirds of posterior circulation stroke patients lack focal neurologic symptoms depending on examiner skill 1.

2. Vertebrobasilar Insufficiency/TIA

• Transient ischemia in posterior circulation can present identically
• Same risk factor profile as stroke
• May herald complete infarction 1

3. Vestibular Neuritis/Labyrinthitis (Benign Peripheral Cause)

• Most common benign cause of isolated AVS with normal neurologic exam 1
• However, cannot be diagnosed clinically without proper HINTS examination (Head Impulse, Nystagmus, Test of Skew)
• The description lacks documentation of nystagmus characteristics, head impulse testing, or skew deviation
• In high-risk patients like this, peripheral causes should be diagnoses of exclusion

Secondary Considerations (Less Likely but Possible)

4. Severe Hyperglycemia with Osmotic Effects

• Glucose of 28 mmol/L (504 mg/dL) is severely elevated
• Hyperosmolar states can cause neurological symptoms including altered mental status and ataxia 2
• However, isolated vertigo-ataxia-vomiting without encephalopathy is atypical
• Osmotic demyelination syndrome has been reported with severe hyperglycemia 2, though this typically develops after correction, not acutely

5. Hypertensive Emergency with Posterior Reversible Encephalopathy Syndrome (PRES)

• BP 150/80 is elevated but not typically in hypertensive emergency range
• PRES usually presents with headache, seizures, visual changes, and altered consciousness
• Less likely given presentation

6. Vestibular Migraine

• Can present with vertigo and ataxia
• Typically episodic rather than persistent
• Less likely as first presentation at age 53 without migraine history 3

7. Cardiac Arrhythmia with Cerebral Hypoperfusion

• ECG reported normal, making this less likely
• Would expect more global symptoms rather than isolated vestibular syndrome

Critical Pitfalls to Avoid

1. Assuming "normal physical exam" means benign disease - Gait ataxia IS an abnormal finding
2. Relying on presence/absence of focal deficits - Most posterior circulation strokes in AVS lack obvious focal signs 1
3. Attributing symptoms to hyperglycemia alone - While glucose is elevated, this presentation pattern demands stroke exclusion first
4. Performing HINTS examination without proper training - When performed by non-experts, HINTS has mixed results 1

Immediate Diagnostic Approach

Urgent MRI brain with diffusion-weighted imaging (DWI) is mandatory 1:

• MRI with DWI is the gold standard for detecting acute posterior circulation infarcts
• CT has very low sensitivity (<1%) for detecting contributory CNS pathology in isolated vertigo 1
• Critical caveat: Early MRI can be false-negative in 20-50% of small brainstem strokes 3
• If MRI unavailable or negative but clinical suspicion remains high, repeat imaging in 24-48 hours or obtain MRA/CTA to evaluate vertebrobasilar circulation

HINTS examination (if examiner is properly trained):

• When performed by specialists, HINTS is more sensitive than early MRI for stroke (100% vs 46%) 1
• However, HINTS has NOT been validated in patients without nystagmus or with already-resolved symptoms 3
• Non-expert performance yields unreliable results 1

Concurrent management:

• Correct hyperglycemia cautiously (avoid rapid osmotic shifts)
• Monitor for stroke evolution
• Vascular neurology consultation

Bottom line: In a 53-year-old with hypertension, diabetes, and acute vestibular syndrome with gait ataxia, posterior circulation stroke is the working diagnosis until imaging proves otherwise 1, 4, 5.