What causes unilateral vasomotor symptoms?

Causes of One-Sided Vasomotor Symptoms

Unilateral vasomotor symptoms are most commonly caused by neurological disorders affecting the autonomic nervous system, including primary or secondary autonomic failure syndromes, vascular pathologies, or localized nerve damage. 1

Neurological Causes

• Autonomic dysfunction: Primary autonomic failure syndromes (pure autonomic failure, multiple system atrophy, Parkinson's disease with autonomic failure) or secondary autonomic failure (diabetes, amyloidosis, uremia, spinal cord injury) can present with unilateral vasomotor symptoms 1
• Stroke or TIA: Cerebrovascular events affecting autonomic centers in the brain can cause unilateral vasomotor disturbances 1
• Cranial neuropathies: Damage to specific cranial nerves can result in unilateral autonomic dysfunction with vasomotor symptoms 1
• Horner's syndrome: Disruption of sympathetic innervation to one side of the face can cause unilateral vasomotor changes 1

Vascular Causes

• Thromboangiitis obliterans (Buerger's disease): An inflammatory thrombotic disorder that can affect arteries unilaterally, particularly in young tobacco users 1
• Thromboembolic disease: Macroemboli from cardiac sources or microemboli from arterial sources can cause unilateral vasomotor symptoms 1
• Vasculitis: Medium-sized vessel vasculitis (polyarteritis nodosa, temporal arteritis) can present with unilateral symptoms 1
• Radiation-associated arteritis: Can affect vessels of any size and present with unilateral symptoms in the irradiated area 1

Localized Causes

• Vasomotor rhinitis: Can present unilaterally with nasal congestion and increased secretion triggered by temperature changes, humidity, odors, or irritants 1
• Reflex syncope with unilateral presentation: Vasovagal, situational, or carotid sinus syncope can sometimes manifest with unilateral vasomotor symptoms 1
• Nerve compression: Physical compression of autonomic nerve fibers can lead to unilateral vasomotor symptoms 1

Systemic Conditions with Unilateral Presentation

• Connective tissue disorders: Systemic lupus erythematosus, rheumatoid arthritis, and scleroderma can sometimes present with unilateral vasomotor symptoms 1
• Prothrombotic states: Conditions with specific abnormalities in the clotting system (protein C, protein S, or antithrombin III deficiencies) can manifest unilaterally 1
• Malignancy: Certain tumors can cause paraneoplastic autonomic dysfunction with unilateral presentation 1

Clinical Approach to Evaluation

• Vascular assessment: Evaluate for abnormal pulse examination, temperature differences, color changes, and capillary refill on the affected side 1
• Neurological examination: Assess for other neurological deficits that might indicate the location of the lesion affecting autonomic function 1
• Autonomic testing: Consider specialized testing including Valsalva maneuver, deep-breathing testing, and ambulatory blood pressure monitoring when autonomic dysfunction is suspected 1
• Imaging: MRI of the brain and/or spine may be indicated if central nervous system pathology is suspected; CT angiography for vascular causes 1

Important Considerations

• Unilateral vasomotor symptoms should never be dismissed as psychogenic without thorough evaluation, as they often indicate underlying neurological or vascular pathology 1
• The pattern, triggers, and associated symptoms are crucial in determining the underlying cause 1
• Patients with unilateral vasomotor symptoms should be evaluated for potentially serious conditions like stroke, vasculitis, or malignancy 1

Common Pitfalls

• Misdiagnosis as anxiety: Unilateral vasomotor symptoms are often incorrectly attributed to anxiety or stress 1
• Incomplete evaluation: Failing to perform a thorough neurological and vascular assessment can miss important underlying causes 1
• Overlooking medications: Certain medications can cause or exacerbate unilateral vasomotor symptoms, particularly those affecting autonomic function 1
• Ignoring systemic disease: Focusing only on local causes while missing systemic conditions that can present with unilateral symptoms 1