What could be causing numbness and dizziness in a patient with a history of neurocirculatory asthenia?

Differential Diagnosis: Numbness of All Extremities and Dizziness in Neurocirculatory Asthenia

In a patient with neurocirculatory asthenia presenting with numbness of all extremities and dizziness, the most critical diagnosis to exclude immediately is vertebrobasilar insufficiency, which can cause both symptoms and may precede stroke by weeks to months. 1

Primary Diagnostic Considerations

Vertebrobasilar Insufficiency (Highest Priority)

• Dizziness is a cardinal symptom of vertebral artery disease, along with vertigo, diplopia, perioral numbness, bilateral sensory deficits, ataxia, and syncope 1
• Vertebral artery atherosclerosis accounts for approximately 20% of posterior circulation strokes 1, 2
• Isolated transient vertigo may precede vertebrobasilar stroke by weeks or months, with attacks typically lasting less than 30 minutes 1
• Bilateral sensory deficits (numbness of all extremities) combined with dizziness strongly suggests posterior circulation compromise 1
• The annual stroke risk for symptomatic intracranial vertebral stenosis reaches 8% 2

Peripheral Neuropathy (Secondary Consideration)

• Peripheral neuropathy presents with distal, symmetric sensory or sensorimotor polyneuropathy 1
• Common symptoms include sensory loss, paresthesias, numbness, cramps, burning feet, and tingling 1
• However, peripheral neuropathy alone does not explain concurrent dizziness, making this less likely as a sole diagnosis 1

Neurocirculatory Asthenia Manifestations

• Dizziness and faintness are common symptoms in neurocirculatory asthenia itself 3
• Respiratory complaints, palpitation, chest discomfort, and fatigue are nearly universal 3
• However, numbness of all extremities is NOT a typical feature of neurocirculatory asthenia 3
• The physical examination in uncomplicated neurocirculatory asthenia is normal 3

Critical Diagnostic Workup

Immediate Evaluation Required

• Complete neurovascular assessment with detailed neurological examination to identify focal deficits suggesting central nervous system involvement 4
• CTA or contrast-enhanced MRA (sensitivity 94%, specificity 95%) to evaluate vertebrobasilar circulation 1, 2
• Ultrasound is inadequate (sensitivity only 70%) for vertebral artery evaluation 1
• Catheter-based angiography may be required for definitive assessment if noninvasive imaging is inadequate 1, 2

Physical Examination Priorities

• Assess for nystagmus type: gaze-evoked nystagmus suggests central lesions 1
• Evaluate severity of postural instability 1
• Document presence of additional neurological signs (ataxia, diplopia, dysarthria) 1
• Perform HINTS examination (head-impulse, nystagmus, test of skew) if trained 1
• Orthostatic blood pressure measurement to exclude postural hypotension 1

Distinguishing Features from Benign Causes

• Nystagmus in vertebrobasilar insufficiency does not fatigue and is not easily suppressed by gaze fixation, unlike benign paroxysmal positional vertigo 1
• Dix-Hallpike maneuver will be negative in vertebrobasilar insufficiency 1
• Absence of hearing loss helps distinguish from Meniere disease 1

Other Differential Diagnoses to Consider

Medication-Related Causes

• Antihypertensive medications and cardiovascular drugs may produce dizziness and vertigo 1
• Review all current medications, particularly if recently started 1

Metabolic/Systemic Causes

• Diabetes mellitus can cause both autonomic neuropathy (dizziness) and peripheral neuropathy (numbness) 1
• Vitamin B12 deficiency can cause peripheral neuropathy with sensory ataxia 1

Anxiety/Panic Disorder

• Can produce lightheadedness and dizziness, often attributed to hyperventilation 1
• High prevalence of vestibular dysfunction in anxiety patients 1
• Does not explain bilateral extremity numbness 1

Immediate Management Approach

If Vertebrobasilar Insufficiency Suspected

• Immediate emergency department referral for patients with high-grade vertebral stenosis and intermittent dizziness due to high stroke risk 4
• Initiate antithrombotic therapy (aspirin or aspirin plus dipyridamole) 2
• Aggressive atherosclerotic risk factor modification: hypertension control, statin therapy, diabetes management, smoking cessation 2
• Coordinate multidisciplinary care with neurology, neurosurgery, and interventional radiology 4

If Peripheral Neuropathy Suspected

• Electromyography with peripheral nerve neurophysiological tests 1
• Consider intraepidermal nerve fiber density assessment 1
• Evaluate for underlying causes (diabetes, vitamin deficiencies, toxins) 1

Critical Pitfalls to Avoid

• Do not dismiss dizziness as purely functional in neurocirculatory asthenia when accompanied by numbness 4
• Do not delay evaluation of intermittent dizziness in the setting of vascular risk factors, as this can lead to preventable strokes 4
• Do not rely on ultrasound alone for vertebral artery assessment due to poor sensitivity 1
• Do not assume symptoms are benign without excluding central causes, as 75-80% of patients with vertebrobasilar stroke may lack focal neurologic deficits initially 1