Paresthesia
Paresthesia is an abnormal sensation or combination of sensations—commonly described as numbness, prickling, or tingling—felt along peripheral nerve pathways; these sensations generally aren’t painful. Unpleasant or painful sensations, on the other hand, are termed dysesthesias. Paresthesia may develop suddenly or gradually and may be transient or permanent.
A common symptom of many neurologic disorders, paresthesia may also result from a systemic disorder or from a particular drug. It may reflect damage or irritation of the parietal lobe, thalamus, spinothalamic tract, or spinal or peripheral nerves—the neural circuit that transmits and interprets sensory stimuli.
History and physical examination
First, explore the paresthesia. When did the abnormal sensations begin? Have the patient describe their character and distribution. Ask about associated signs and symptoms, such as sensory loss and paresis or paralysis. Next, take a medical history, including neurologic, cardiovascular, metabolic, renal, and chronic inflammatory disorders, such as arthritis or lupus. Has the patient recently sustained a traumatic injury or had surgery or an invasive procedure that may have damaged peripheral nerves?
Focus the physical examination on the patient’s neurologic status. (See Differential diagnosis: Paresthesia, pages 602 and 603.) Assess his level of consciousness (LOC) and cranial nerve function. Test muscle strength and deep tendon reflexes (DTRs) in limbs affected by paresthesia. Systematically evaluate light touch, pain, temperature, vibration, and position sensation. (See Testing for analgesia, pages 48 and 49.) Note skin color and temperature, and palpate pulses.
Medical causes
Arterial occlusion (acute)
With this disorder, sudden paresthesia and coldness may develop in one or both legs with a saddle embolus. Paresis, intermittent claudication, and aching pain at rest are also characteristic. The extremity becomes mottled with a line of temperature and color demarcation at the level of occlusion. Pulses are absent below the occlusion, and capillary refill time is increased.
Arteriosclerosis obliterans
This disorder produces paresthesia, intermittent claudication (most common symptom), diminished or absent popliteal and pedal pulses, pallor, paresis, and coldness in the affected leg.
Arthritis
Rheumatoid or osteoarthritic changes in the cervical spine may cause paresthesia in the neck, shoulders, and arms. The lumbar spine occasionally is affected, causing paresthesia in one or both legs and feet.
Brain tumor
Tumors affecting the sensory cortex in the parietal lobe may cause progressive contralateral paresthesia accompanied by agnosia, apraxia, agraphia, homonymous hemianopsia, and loss of proprioception.
Buerger’s disease
With this smoking-related inflammatory occlusive disorder, exposure to cold makes the feet cold, cyanotic, and numb; later, they redden, become hot, and tingle. Intermittent claudication, which is aggravated by exercise and relieved by rest, is also common. Other findings include weak peripheral pulses, migratory superficial thrombophlebitis and, later, ulceration, muscle atrophy, and gangrene.
Diabetes mellitus
Diabetic neuropathy can cause paresthesia with a burning sensation in the hands and legs.Other findings include insidious, permanent anosmia, fatigue, polyuria, polydipsia, weight loss, and polyphagia.
Guillain-Barré syndrome
With this syndrome, transient paresthesia may precede muscle weakness, which usually begins in the legs and ascends to the arms and facial nerves. Weakness may progress to total paralysis. Other findings include dysarthria, dysphagia, nasal speech, orthostatic hypotension, bladder and bowel incontinence, diaphoresis, tachycardia and, possibly, signs of life-threatening respiratory muscle paralysis.
Head trauma
Unilateral or bilateral paresthesia may occur when head trauma causes a concussion or contusion; however, sensory loss is more common. Other findings include variable paresis or paralysis, decreased LOC, headache, blurred or double vision, nausea and vomiting, dizziness, and seizures.
Heavy metal or solvent poisoning
Exposure to industrial or household products containing lead, mercury, thallium, or organophosphates may cause paresthesia of acute or gradual onset. Mental status changes, tremors, weakness, seizures, and GI distress are also common.
Herniated disk
Herniation of a lumbar or cervical disk may cause acute or gradual onset of paresthesia along the distribution pathways of affected spinal nerves. Other neuromuscular effects include severe pain, muscle spasms, and weakness that may progress to atrophy unless herniation is relieved.
Herpes zoster
An early symptom of this disorder, paresthesia occurs in the dermatome supplied by the affected spinal nerve. Within several days, this dermatome is marked by a pruritic, erythematous, vesicular rash associated with sharp, shooting, or burning pain.
Hyperventilation syndrome
Usually triggered by acute anxiety, this syndrome may produce transient paresthesia in the hands, feet, and perioral area, accompanied by agitation, vertigo, syncope, pallor, muscle twitching and weakness, carpopedal spasm, and cardiac arrhythmias.
Hypocalcemia
Asymmetrical paresthesia usually occurs in the fingers, toes, and circumoral area early in this disorder. Other signs and symptoms are muscle weakness, twitching, or cramps; palpitations; hyperactive DTRs; carpopedal spasm; and positive Chvostek’s and Trousseau’s signs.
Migraine headache
Paresthesia in the hands, face, and perioral area may herald an impending migraine headache. Other prodromal symptoms include scotomas, hemiparesis, confusion, dizziness, and photophobia. These effects may persist during the characteristic throbbing headache and continue after it subsides.
Multiple sclerosis (MS)
With this disorder, demyelination of the sensory cortex or spinothalamic tract may produce paresthesia—typically one of the earliest symptoms. Like other effects of MS, paresthesia commonly waxes and wanes until the later stages, when it may become permanent. Associated findings include muscle weakness, spasticity, and hyperreflexia.
Peripheral nerve trauma
Injury to any major peripheral nerve can cause paresthesia—often dysesthesia—in the area supplied by that nerve. Paresthesia begins shortly after trauma and may be permanent. Other findings are flaccid paralysis or paresis, hyporeflexia, and variable sensory loss.
Peripheral neuropathy
This syndrome can cause progressive paresthesia in all extremities. The patient also commonly displays muscle weakness, which may lead to flaccid paralysis and atrophy; loss of vibration sensation; diminished or absent DTRs; neuralgia; and cutaneous changes, such as glossy, red skin and anhidrosis.
Rabies
Paresthesia, coldness, and itching at the site of an animal bite herald the prodromal stage of rabies. Other prodromal signs and symptoms are fever, headache, photophobia, hyperesthesia, tachycardia, shallow respirations, and excessive salivation, lacrimation, and perspiration.
Raynaud’s disease
Exposure to cold or stress makes the fingers turn pale, cold, and cyanotic; with rewarming, they become red and paresthetic. Ulceration may occur in chronic cases.
Seizure disorders
Seizures originating in the parietal lobe usually cause paresthesia of the lips, fingers, and toes. The paresthesia may act as auras that precede tonic-clonic seizures.
Spinal cord injury
Paresthesia may occur in partial spinal cord transection, after spinal shock resolves. It may be unilateral or bilateral, occurring at or below the level of the lesion. Associated sensory and motor loss is variable. (See Understanding spinal cord syndromes, page 599.) Spinal cord disorders may be associated with paresthesia on head flexion (Lhermitte’s sign).
Spinal cord tumors
Paresthesia, paresis, pain, and sensory loss along nerve pathways served by the affected cord segment result from such tumors. Eventually, paresis may cause spastic paralysis with hyperactive DTRs (unless the tumor is in the cauda equina, which produces hyporeflexia) and, possibly, bladder and bowel incontinence.
Stroke
Although contralateral paresthesia may occur with stroke, sensory loss is more common. Associated features vary with the artery affected and may include contralateral hemiplegia, decreased LOC, and homonymous hemianopsia.
Systemic lupus erythematosus
This disorder may cause paresthesia, but its primary signs and symptoms include nondeforming arthritis (usually of hands, feet, and large joints), photosensitivity, and a “butterfly rash” that appears across the nose and cheeks.
Tabes dorsalis
With this disorder, paresthesia—especially of the legs—is a common, but late, symptom. Other findings include ataxia, loss of proprioception and pain and temperature sensation, absent deep tendon reflexes, Charcot’s joints, Argyll Robertson pupils, incontinence, and impotence.
Thoracic outlet syndrome
Paresthesia occurs suddenly in this syndrome when the affected arm is raised and abducted. The arm also becomes pale and cool with diminished pulses. Unequal blood pressure between arms may be noted.
Transient ischemic attack (TIA)
Paresthesia typically occurs abruptly with a TIA and is limited to one arm or another isolated part of the body. It usually lasts about 10 minutes and is accompanied by paralysis or paresis. Associated findings include decreased LOC, dizziness, unilateral vision loss, nystagmus, aphasia, dysarthria, tinnitus, facial weakness, dysphagia, and ataxic gait.
Vitamin B deficiency
Chronic thiamine or vitamin B12 deficiency may cause paresthesia and weakness in the arms and legs. Burning leg pain, hypoactive DTRs, and variable sensory loss are common in thiamine deficiency; vitamin B12 deficiency also produces mental status changes and impaired vision.
Other causes
Drugs
Phenytoin, chemotherapeutic agents (such as vincristine, vinblastine, and procarbazine), d-penicillamine, isoniazid, nitrofurantoin, chloroquine, and parenteral gold therapy may produce transient paresthesia that disappears when the drug is discontinued.
Radiation therapy
Long-term radiation therapy eventually may cause peripheral nerve damage, resulting in paresthesia.
Special considerations
Because paresthesia is commonly accompanied by patchy sensory loss, teach the patient safety measures. For example, have him test bath water with a thermometer.
Pediatric pointers
Although children may experience paresthesia associated with the same causes as adults, many are unable to describe this symptom. Nevertheless, hereditary polyneuropathies are usually first recognized in childhood.
Pictures
Book Source Details
- Book Title: Professional Guide to Signs & Symptoms (Fifth Edition)
- Author(s): Springhouse
- Year of Publication: 2006
- Copyright Details: Professional Guide to Signs & Symptoms (Fifth Edition), Copyright © 2006 Lippincott Williams & Wilkins.
Other Book Chapters Related to Foot numbness
Read excerpts from these other book chapters related to Foot numbness:
Medical Books Excerpts
- Paresthesia
- "Professional Guide to Signs & Symptoms (Fifth Edition)" (2006)
- [ read ]
- Paresthesia
- "Signs & Symptoms: A 2-in-1 Reference for Nurses" (2007)
- [ read ]
Copyright Details: Professional Guide to Signs & Symptoms (Fifth Edition), Copyright © 2008 Williams & Wilkins.
More About Causes of Foot numbness
» Next page: Paresthesia and Dysesthesia (The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter)
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