In a hypertensive, diabetic patient who has had three days of imbalance without vertigo, two days of rabbit‑like mouth movements, and normal cerebellar examination including a normal finger‑nose test, what is the most likely diagnosis?

Likely Diagnosis: Diabetic Autonomic Neuropathy with Possible Cerebellar Stroke

In this hypertensive, diabetic patient presenting with 3 days of imbalance without vertigo and 2 days of involuntary mouth movements ("rabbit-like"), despite normal cerebellar finger-nose testing, the most likely diagnosis is diabetic autonomic neuropathy affecting vestibular function, though acute cerebellar stroke must be urgently excluded given the acute presentation.

Immediate Diagnostic Considerations

Why Cerebellar Stroke Must Be Ruled Out First

• Cerebellar infarction can be difficult to diagnose, especially when chief complaints include dizziness and imbalance 1
• It is a common pitfall to miss truncal ataxia during bedside examination - the finger-nose test alone is insufficient 1
• Initial CT can be normal in as many as 25% of cerebellar stroke patients 1
• Peak swelling occurs several days after onset, meaning this patient at day 3 is in the critical window 1
• Deterioration with cerebellar stroke typically occurs within 72-96 hours, exactly matching this patient's timeline 1

Critical Action Required

• Obtain urgent brain MRI with diffusion-weighted imaging (DWI) to definitively exclude cerebellar infarction 1
• Assess for truncal ataxia specifically (have patient sit unsupported and observe for swaying) 1
• Check for other cerebellar signs beyond finger-nose: heel-shin test, gait assessment, Romberg test 1

If Stroke is Excluded: Diabetic Vestibular Dysfunction

The Involuntary Mouth Movements

The "rabbit-like" mouth movements for 2 days represent a distinct neurological finding that could indicate:

• Focal motor involvement suggesting central pathology
• Possible brainstem involvement affecting cranial nerve nuclei
• Orofacial dyskinesia which can occur with metabolic derangements in diabetes

Diabetic Vestibular and Balance Dysfunction

Type 2 diabetes damages vestibular and balance systems, with effects more prevalent in patients with higher blood glucose levels and longer disease duration 2

• The rate of vestibular dysfunction in diabetic patients is 68.4% compared to 8.3% in controls 3
• Semicircular canal dysfunction is more common than otoconial organ dysfunction in diabetics, with 70% showing impaired performance 4
• Diabetic patients have significantly poorer vestibular function on objective testing compared to age-matched controls 4

Why Imbalance Without Vertigo Fits This Pattern

• Diabetic autonomic neuropathy causes orthostatic hypotension and balance disturbances without true vertigo 1
• Symptoms of autonomic neuropathy include orthostatic dizziness without the spinning sensation of vertigo 1
• Chronic hyperglycemia causes peripheral vestibular organ dysfunction through microvascular damage 5

The Hypertension Connection

• Significantly more subjects with stage 2 hypertension had abnormal vestibular test results 6
• Subjects with stage 2 hypertension had high rates of diabetes (34.2%) 6
• Blood pressure in the hypertension stage 2 range is most likely to predict abnormal vestibular findings 6

Recommended Diagnostic Workup

Immediate (Emergency Department/Acute Setting)

• Brain MRI with DWI and ADC sequences to exclude cerebellar or brainstem infarction 1
• Orthostatic vital signs (blood pressure and heart rate supine and after 3 minutes standing) to assess for autonomic dysfunction 1
• Blood glucose and HbA1c to assess glycemic control 1

If Acute Stroke Excluded

• Formal vestibular function testing including electronystagmography (ENG) 3
• Cervical and ocular vestibular-evoked myogenic potentials (VEMPs) to assess saccule and utricle function 4
• Assessment for other diabetic neuropathies: detailed sensory examination with 10-g monofilament, 128-Hz tuning fork for vibration, temperature and pinprick sensation 1
• Cardiovascular autonomic testing including heart rate variability with deep breathing 1

Management Approach

Glycemic Optimization is Critical

• Optimize glucose control to prevent or delay development of neuropathy and slow progression 1
• Well-controlled blood glucose delays progression of diabetic neuropathy 1
• Target HbA1c based on individual factors, but tighter control reduces neuropathy risk 1

Blood Pressure Management

• Optimize blood pressure management to reduce risk or slow progression of diabetic neuropathy 1
• Target blood pressure <130/80 mmHg in most diabetic patients with hypertension 1
• ACE inhibitors or ARBs are preferred antihypertensive agents in diabetic patients 1

Symptomatic Treatment

• Assess and treat symptoms of autonomic neuropathy to improve quality of life 1
• For orthostatic hypotension: increase salt and fluid intake, compression stockings, fludrocortisone or midodrine if needed 1
• Galvanic stimulation of the vestibular system may be effective in reducing blood glucose levels and improving rehabilitation outcomes 2

Common Pitfalls to Avoid

1. Do not rely solely on finger-nose test to exclude cerebellar pathology - truncal ataxia is easily missed 1
2. Do not assume normal initial CT excludes cerebellar stroke - 25% can have normal initial imaging 1
3. Do not dismiss imbalance without vertigo as benign - this pattern is characteristic of diabetic vestibular dysfunction 2, 3
4. Do not overlook the mouth movements - these suggest additional central nervous system involvement requiring investigation
5. Do not delay neuroimaging in a diabetic/hypertensive patient with acute imbalance - stroke risk is substantially elevated 1

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