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Nerve Root Disorders

(Radiculopathies)

By

Michael Rubin

, MDCM, New York Presbyterian Hospital-Cornell Medical Center

Last full review/revision Dec 2020| Content last modified Dec 2020
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Nerve root disorders result in segmental radicular deficits (eg, pain or paresthesias in a dermatomal distribution, weakness of muscles innervated by the root). Diagnosis may require neuroimaging, electrodiagnostic testing, and systemic testing for underlying disorders. Treatment depends on the cause but includes symptomatic relief with nonsteroidal anti-inflammatory drugs, other analgesics, and corticosteroids.

Spinal nerve roots

Spinal nerve roots

Etiology of Nerve Root Disorders

The most common cause of radiculopathies is

Infectious disorders, such as those due to mycobacteria (eg, tuberculosis Tuberculosis (TB) Tuberculosis (TB) is a chronic, progressive mycobacterial infection, often with a period of latency following initial infection. TB most commonly affects the lungs. Symptoms include productive... read more Tuberculosis (TB) [TB]), fungi (eg, histoplasmosis Histoplasmosis Histoplasmosis is a pulmonary and hematogenous disease caused by Histoplasma capsulatum; it is often chronic and usually follows an asymptomatic primary infection. Symptoms are those of pneumonia... read more Histoplasmosis ), or spirochetes (eg, Lyme disease Lyme Disease Lyme disease is a tick-transmitted infection caused by the spirochete Borrelia species. Early symptoms include an erythema migrans rash, which may be followed weeks to months later by neurologic... read more Lyme Disease , syphilis Syphilis Syphilis is caused by the spirochete Treponema pallidum and is characterized by 3 sequential clinical, symptomatic stages separated by periods of asymptomatic latent infection. Common manifestations... read more Syphilis ), sometimes affect nerve roots. Herpes zoster infection Herpes Zoster Herpes zoster is infection that results when varicella-zoster virus reactivates from its latent state in a posterior dorsal root ganglion. Symptoms usually begin with pain along the affected... read more Herpes Zoster usually causes a painful radiculopathy with dermatomal sensory loss and characteristic rash, but it may cause a motor radiculopathy with segmental weakness and reflex loss. Cytomegalovirus-induced polyradiculitis is a complication of AIDS.

Symptoms and Signs of Nerve Root Disorders

Radiculopathies tend to cause characteristic radicular syndromes of pain and segmental neurologic deficits based on the cord level of the affected root (see table Symptoms of Common Radiculopathies by Cord Level Symptoms of Common Radiculopathies by Cord Level Nerve root disorders result in segmental radicular deficits (eg, pain or paresthesias in a dermatomal distribution, weakness of muscles innervated by the root). Diagnosis may require neuroimaging... read more ). Muscles innervated by the affected motor root become weak and atrophy; they also may be flaccid with fasciculations. Sensory root involvement causes sensory impairment in a dermatomal distribution. Corresponding segmental deep tendon reflexes may be diminished or absent. Electric shock–like pains may radiate along the affected nerve root’s distribution.

Table
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Pain may be exacerbated by movements that transmit pressure to the nerve root through the subarachnoid space (eg, moving the spine, coughing, sneezing, doing the Valsalva maneuver).

Lesions of the cauda equina, which affect multiple lumbar and sacral roots, cause radicular symptoms in both legs and may impair sphincter and sexual function.

  • A sensory level (an abrupt change in sensation below a horizontal line across the spine)

  • Flaccid paraparesis or quadriparesis

  • Reflex abnormalities below the site of compression

  • Early-onset hyporeflexia followed later by hyperreflexia

  • Sphincter dysfunction

Diagnosis of Nerve Root Disorders

  • Neuroimaging

  • Sometimes electrodiagnostic tests

Radicular symptoms require MRI or CT of the affected area. Myelography is needed only if MRI is contraindicated (eg, because of an implanted pacemaker or presence of other metal) and CT is inconclusive. The area imaged depends on symptoms and signs; if the level is unclear, electrodiagnostic tests should be done to localize the affected root, but they cannot identify the cause.

If imaging does not detect an anatomic abnormality, cerebrospinal fluid analysis is done to check for infectious or inflammatory causes, and fasting plasma glucose is measured to check for diabetes Diagnosis Diabetes mellitus is impaired insulin secretion and variable degrees of peripheral insulin resistance leading to hyperglycemia. Early symptoms are related to hyperglycemia and include polydipsia... read more .

Treatment of Nerve Root Disorders

  • Treatment of the cause and of pain

  • Surgery (as a last resort)

Specific causes of nerve root disorders are treated.

Acute pain requires appropriate analgesics (eg, acetaminophen, nonsteroidal anti-inflammatory drugs [NSAIDs], sometimes opioids). NSAIDs are particularly useful for disorders that involve inflammation. Muscle relaxants, sedatives, and topical treatments rarely provide additional benefit. If symptoms are not relieved with nonopioid analgesics, corticosteroids can be given systemically or as an epidural injection; however, analgesia tends to be modest and temporary. Methylprednisolone may be given, tapered over 6 days, starting with 24 mg orally once a day and decreased by 4 mg a day.

Management of chronic pain Treatment Chronic pain is pain that persists or recurs for > 3 months, persists > 1 month after resolution of an acute tissue injury, or accompanies a nonhealing lesion. Causes include chronic disorders... read more can be difficult; acetaminophen and NSAIDs are often only partly effective, and long-term use of NSAIDs has substantial risks. Opioids have a high risk of addiction. Tricyclic antidepressants and antiseizure drugs may be effective, as may physical therapy and consultation with a mental health practitioner. For a few patients, alternative medical treatments (eg, transdermal electrical nerve stimulation Electrical stimulation Treatment of pain and inflammation aims to facilitate movement and improve coordination of muscles and joints. Nondrug treatments include therapeutic exercise, heat, cold, electrical stimulation... read more , spinal manipulation Chiropractic In chiropractic (a manipulative and body-based practice), the relationship between the structure of the spine and other articulating surfaces and their interaction with the nervous system is... read more , acupuncture Acupuncture Acupuncture, a therapy within traditional Chinese medicine, is one of the most widely accepted complementary therapies in the western world and is often part of integrative medicine. Specific... read more , medicinal herbs Overview of Dietary Supplements Dietary supplements are the most commonly used of all integrative, complementary, and alternative therapies, primarily because they are widely available, relatively inexpensive, and can be bought... read more ) may be tried if all other treatments are ineffective.

If the pain is intractable or if progressive weakness or sphincteric dysfunction suggest spinal compression, surgical decompression may be necessary.

Key Points

  • Suspect a nerve root disorder in patients who have segmental deficits such as sensory abnormalities in a dermatomal distribution (eg, pain, paresthesias) and/or motor abnormalities (eg, weakness, atrophy, fasciculations, hyporeflexia) at a nerve root level.

  • If patients have a sensory level, bilateral flaccid weakness, and/or sphincter dysfunction, suspect spinal cord compression.

  • If clinical findings suggest radiculopathy, do MRI or CT.

  • Use analgesics and sometimes corticosteroids for acute pain, and consider other drugs and other treatments, as well as analgesics, for chronic pain.

  • In patients with progressive weakness and sphincteric dysfunction, consider surgical decompression.

Drugs Mentioned In This Article

Drug Name Select Trade
MEDROL
TYLENOL
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