What are the causes of intermittent paresthesia?

Causes of Intermittent Paresthesia

Intermittent paresthesia (abnormal sensations like tingling, burning, or numbness) is commonly caused by peripheral neuropathies, nerve entrapment syndromes, central nervous system disorders, and metabolic conditions.

Peripheral Causes

• Diabetic peripheral neuropathy (DPN) - The most common cause of peripheral neuropathy, affecting small fibers initially with symptoms of pain, dysesthesias (burning and tingling), and numbness. Symptoms typically follow a distal-to-proximal pattern, starting in the feet 1
• Nerve entrapment syndromes - Such as carpal tunnel syndrome, presenting with characteristic distribution of paresthesias in affected nerves 2
• Medication-induced neuropathy - Particularly from chemotherapeutic agents that can cause dose-dependent peripheral neuropathy 2
• Post-viral neuropathies - Following viral infections, including hepatitis C which can cause paresthesias in up to 50% of infected patients 2
• Buerger disease - A nonatherosclerotic inflammatory vasculitis affecting small and medium-sized distal arteries, presenting with paresthesias, intermittent claudication, and pain 1
• Popliteal artery entrapment syndrome (PAES) - Causes calf claudication, paresthesia, and swelling during exercise, particularly in young adults 1
• External iliac artery endofibrosis (EIAE) - Primarily in endurance athletes, causing lower-extremity weakness, thigh pain, and paresthesias that resolve after cessation of exercise 1

Central Nervous System Causes

• Multiple sclerosis - Can cause paresthesias as part of its neurological manifestations, particularly during relapsing-remitting phases 1, 2
• Ischemic events - Including stroke, transient ischemic attacks, and lacunar infarctions can cause paresthesias 2
• Space-occupying lesions - Brain tumors that compress neural pathways can cause paresthesias 2
• Guillain-Barré syndrome - Presents with distal paresthesias that may progress to weakness 2
• Lyme disease - Can cause peripheral neuropathy with intermittent limb paresthesias and radicular pain 1

Metabolic and Systemic Causes

• Vitamin B12 deficiency - Can cause peripheral neuropathy with paresthesias 1, 3
• Monoclonal gammopathy - Can present with paresthesias as part of polyneuropathy 3
• Fabry's disease - A genetic disorder that can cause acroparesthesias 3
• Vasculopathic conditions - Such as hypertension can contribute to nerve dysfunction and cause paresthesias 2

Mechanical and Load-Related Causes

• Rucksack palsy - A traction or compression injury to the brachial plexus caused by shoulder straps of rucksacks, presenting with paresthesia, paralysis, and muscle weakness of the upper limb 4
• Digitalgia paresthetica - Caused by compression of sensory digital nerves in the foot during load carriage 4

Physiological Mechanisms

• Ischemia - Temporary nerve compression leading to reduced blood flow can cause paresthesias 5
• Hyperventilation - The alkaline shift produced can selectively increase sodium conductance in nerves, leading to paresthesias 5
• Post-ischemic conditions - When blood flow returns after temporary ischemia, paresthesias can occur due to ionic imbalances 5

Diagnostic Approach

• Clinical assessment should include evaluation of pinprick sensation (small fiber function) and vibration sensation using a 128-Hz tuning fork (large-fiber function) 1
• 10-g monofilament testing is recommended annually for patients with diabetes to identify feet at risk 1
• Electromyography with peripheral nerve neurophysiological tests should be used for suspected peripheral nerve involvement 2
• Neuroimaging (MRI, CT) is indicated when central causes are suspected, especially with other neurological findings 2
• In cases of severe or atypical neuropathy, causes other than diabetes should be considered, including neurotoxic medications, heavy metal poisoning, alcohol abuse, vitamin B12 deficiency, renal disease, chronic inflammatory demyelinating neuropathy, inherited neuropathies, and vasculitis 1

Special Considerations

• Intermittent paresthesias with rapid progression, asymmetry, or associated motor signs require urgent evaluation as they may indicate serious conditions like Guillain-Barré syndrome or vasculitis 3
• Paresthesias accompanied by facial weakness, motor weakness, headache, or visual changes may indicate cranial neuropathies or central nervous system pathology requiring neuroimaging 1
• Ultrasonography can be valuable for diagnosing nerve entrapment neuropathies by showing nerve enlargement, hypoechogenic nerve, and intraneural vascularity 3

Understanding the underlying cause of intermittent paresthesia is essential for appropriate management and treatment of this common neurological symptom.