eMedicine Specialties > Physical Medicine and Rehabilitation > Plexopathy

Neoplastic Brachial Plexopathy

Mark A Wren, MD, MPH, Medical Director, Department of Physical Medicine and Rehabilitation, HealthSouth Rehabilitation Hospital of Texarkana

Updated: Jan 26, 2007

Introduction

Background

Neoplastic brachial plexopathy (NBP) is an uncommon diagnosis in most physiatrists' offices, but the condition bears review as it can mimic symptoms of many common upper limb neuropathies. Approximately 10% of all peripheral nerve lesions involve some type of brachial plexus lesion. Neoplastic invasion of the brachial plexus is an uncommon, though not rare, cause of plexopathy. This article reviews the more common issues associated with physiatric treatment of patients with NBP.

Pathophysiology

Lesions of the brachial plexus occur most often secondary to neoplasms that reach the plexus by direct extension (Pancoast syndrome) or, more commonly, by metastasis through lymphatics from the axilla. Pain in the shoulder, radiating down the limb, may be observed, as well as pain in the medial forearm and hand with lower trunk innervation (C8-T1 roots) in some series. The most common pathophysiology revealed on electrodiagnostic tests is axonal loss. Peripheral pain mechanisms may include lowering of the nociceptor threshold by prostaglandins and other noxious chemical substances and persistent nociceptor stimulation. Compression or infiltration of the nerves of the plexus by a tumor may produce neuralgia and inflammation.

Frequency

United States

Approximately 14% of all upper limb neurologic lesions are due to brachial plexopathy of all types. Neoplastic plexopathies were responsible for 1.4 and 14.5% of symptoms in 2 series of patients who had undergone surgery. Insufficient data have been published to determine the frequency of NBP, but symptomatic NBP has been estimated to occur in 4% of patients with lung cancer and 2% of patients with breast cancer.

International

The international incidence of NBP is unknown.

Mortality/Morbidity

Primary neoplasms of the brachial plexus generally are benign, while secondary neoplasms are malignant. Most secondary tumors are metastatic, contributing to higher mortality.

Sex

Solitary neoplastic lesions of the brachial plexus are more common in females. Neurofibromas demonstrate a male-to-female ratio of 1:1.

Age

Incidence of metastatic neoplasm of the brachial plexus increases with age; thus, the condition is more common in elderly patients.

Clinical

History

Pain is the most common presenting symptom of NBP (seen in 89% of the Kori series). In one series, 17 of 55 patients presented with brachial plexopathy as the initial manifestation of cancer. Patients with NBP may present with shoulder pain and paresthesias with radiation of pain into the medial forearm and/or hand. Symptoms often are related to breast or lung metastases or lymphoma in a generalized plexus involvement, sometimes with a lower trunk predominance. Symptoms may be diffuse but more often involve the C8-T1 dermatomes and myotomes (mimicking ulnar neuropathy or C8 or T1 radiculopathy).

The Pancoast syndrome (superior pulmonary sulcus tumor) usually is caused by carcinoma at the lung apex, encroaching on the lower trunk of the brachial plexus. Patients with this condition frequently are males with a history of cigarette smoking. For primary brachial plexus tumors, usually from the nerve sheath (neurofibromas and schwannomas), slightly higher incidence is noted in the upper brachial plexus; thus, symptoms appear in the C5-C6 dermatomes and myotomes (mimicking C5 or C6 radiculopathy or possibly carpal tunnel syndrome).

Radiation-induced brachial plexopathy (RBP) is another relevant topic since it can be confused with NBP. As treatment may be different for the two conditions, differentiation between RBP and NBP is important, although it may be difficult. As many as 73% of patients who have undergone radiotherapy at more than 60 Gy develop plexopathy. Overall incidence of brachial plexopathy is approximately 1.8% of treated patients; however, several factors play a role in development of the condition, including dose (incidence is higher with doses more than 50 Gy), volume irradiated, and treatment technique, as well as whether chemotherapy is administered concurrently. Emami reports 5% incidence of NBP at 5 years when the patient has been treated at doses of 60 Gy to the entire plexus; however, up to one third of patients with RBP find that the deterioration may stop after several years.

• Some historical findings suggestive of NBP include the following:
  • Onset of limb pain less than 6 months following radiation
  • Rapid progression
  • Horner syndrome (in two thirds of patients with Pancoast syndrome)
  • Severe pain predominant
  • Other metastases
  • Focal mass or neoplasm on biopsy
• The most reliable feature of NBP (in 80% of patients) is early severe unrelenting pain. Fewer than 20% of RBP patients present with pain, and approximately 33% have minimal or no pain throughout the course of the disease. Two thirds of patients with RBP show severe neurologic deficit progression over several years, while in one third of patients, progression spontaneously ceases after 1-3 years (Killer, 1990). More common findings in RBP include the following:
  • Slowly progressive course, duration greater than 4 years
  • Predominant paresthesias
  • Median sensory amplitude decreased early
  • Involvement of the upper trunk or C5-C6 portions of the plexus
  • Conduction block on supraclavicular stimulation
  • Myokymia on needle examination

Physical

Examination findings depend on the specific parts of the plexus involved. As can be inferred from the information above, weakness in the hand intrinsics and sensory loss in the C8 and/or T1 dermatomes may be present with the most common lower trunk involvement. For more widespread involvement, motor and sensory loss may be present throughout the limb.

Less common primary neoplasms may occur and present as limb pain and/or a tender mass, causing radiating paresthesias upon palpation. Sensory and motor deficits may be found corresponding to the tumor's location in the plexus; however, weakness and sensory changes in the lower trunk distribution of patients with Pancoast syndrome are reported in approximately one third of cases.

Causes

The most common causes of NBP are metastatic lesions from breast or lung cancer, and the clinician also should be aware of possible concurrent cervical spine metastases. Primary NBP is less common than secondary metastatic lesions and usually is benign. Neural sheath tumors comprise 67-85% of primary NBP, and benign neurofibromas represent 66% of primary NBP tumors. Most neurofibromas are solitary, fusiform, and supraclavicular, and they are more common in females than males (3:1 in one series). A smaller number of plexus neurofibromas (37-42%) are associated with Von Recklinghausen disease. They can arise or extend intraspinally, and their nerve fibers often are nonfunctional.

Benign schwannomas (eg, neurinomas, neurilemomas) are the second most common type of sheath tumors, comprising about 20%. Approximately 15% of neural sheath tumors are malignant (eg, neurogenic sarcomas, fibrosarcomas). Many of these malignant tumors occur in tumors that initially are benign and undergo malignant transformation, as occurs often in Von Recklinghausen disease. They may develop many years after radiation for Hodgkin disease or breast cancer. Among other types of primary neoplasms, only lymphomas metastasize to the brachial plexus with any appreciable frequency. Rarely, NBP may occur as a paraneoplastic syndrome in patients with Hodgkin lymphoma, encephalomyelitis, and small cell carcinoma of the lung.

Differential Diagnoses

Other Problems to Be Considered

Neuralgic amyotrophy
Subacromial bursitis
Supraspinatus tendonitis
Paraneoplastic syndrome

Workup

Laboratory Studies

• A general lab survey, such as a complete metabolic panel, complete blood count, and urinalysis, usually has been obtained by the primary physician and can be used to screen for signs of neoplasm. (More involved studies exist, but they are beyond the scope of this text/specialty.) If a patient is referred for what might be thought of as simple shoulder pain and turns out to have constitutional symptoms (eg, fevers, weight loss, malaise) and signs of brachial plexopathy, other lab tests certainly may be of value. Examples include a carcinoembryonic antigen (CEA) in a patient with prior colon cancer, a prostate specific antigen (PSA) in a patient with prior prostate cancer, or serum protein electrophoresis (SPEP) in a patient with back pain and pain at rest.

Imaging Studies

• Plain radiographs of the chest, shoulder, and cervical spine should be obtained to look for neoplastic changes.
• MRI of the plexus has a high sensitivity (some studies have reported 100%) in detecting neoplastic involvement of the brachial plexus; however, both CT scan and MRI can present difficulty detecting infiltrating neoplasms and distinguishing them from radiation fibrosis. A well-defined mass lesion on CT scans or MRIs is more suggestive of NBP than RBP.
• Bone scan may be helpful in finding evidence of metastases.
• Myelography may be more successful at finding epidural metastasis extruding through neural foramina (so-called dumbbell tumor).
• Positron emission tomography may be useful in identifying metastasis in or near the brachial plexus; FDG-PET identifies tumors not clearly imaged by CT or MR scanning in some patients.

Other Tests

• The conventional diagnostic procedures for differentiating brachial plexopathy are nerve conduction and electromyography studies. Advances in MRI techniques recently have shown promise as well.
• In general, electrodiagnostic examination is used to localize a lesion, characterize its pathology, and establish prognosis and facilitate a treatment plan. The key question is whether the limb weakness is due to axonotmetic (dead) or neurapraxic (functionally blocked) axons.
• Nerve conduction studies (NCS) may reveal axon loss that often is so severe that lower trunk-mediated sensory potentials (eg, ulnar, medial antebrachial) are absent, and motor responses (median and ulnar) are of low amplitude or absent. Needle examination often reveals motor unit potential loss and spontaneous activity. For axonotmetic lesions, the longer regrowth distance (especially for the lower plexus, where reinnervation must reach the hand) indicates a less favorable prognosis. Neurapraxic lesions are observed less commonly in NBP than RBP, but, barring progression of the lesion/mass, function resumes relatively rapidly, and the prognosis is excellent.
• Comparison of the amplitude of a peripheral evoked response after 7 days with that of the contralateral side can provide an estimate of the degree of injury/recovery. The number of voluntary motor units on needle examination is also a guide to outcome. Peak muscle strength can be regained even with 50% axon loss, although this gain is at the expense of muscle endurance. Remarkably, in muscles where high force or sustained use is not needed, a 90% axon loss might be tolerated, but a year's recovery time might be required. Myokymia is common is RBP, occurring in 50-70% of patients, but it is rare in NBP (4%). Despite the potential utility of electrodiagnostic studies, limitations exist. When pain is the only initial symptom, EMG results may be within the reference range, although the results almost always reveal abnormalities by the time permanent motor and/or sensory deficits are present.
• Somatosensory evoked potentials (SSEP) are noninvasive tests that may be used to assess sensory impairments associated with NBP.

Histologic Findings

The histopathology for secondary neoplasms most often involves adenocarcinoma, squamous cell carcinoma, or, less often, large cell carcinoma. Of the primary neoplasms, schwannomas are encapsulated tumors, and neurofibromas are unencapsulated tumors believed to arise from the near fascicles.

Treatment

Rehabilitation Program

Physical Therapy

Physical therapy modalities also may be warranted for assisting in pain reduction in patients with NBP. Electrical modalities for pain control, such as transcutaneous electrical nerve stimulation (TENS) or interferential current, are reasonable but are considered to be a relative contraindication when applied directly over a malignant neoplasm. Edema control measures (eg, retrograde massage, elevation, compressive garments) may be considered. A sling or splint can help the patient maintain a comfortable position and protect the affected limb. A sling also can reduce edema, retard shoulder subluxation, and reduce additional traction on the brachial plexus.

Occupational Therapy

See the Physical Therapy section above. Completing a home safety evaluation for patients with NBP and their families is important. The home evaluation should include use of compensatory strategies and adaptive equipment to improve the patient's functional abilities. For example, a patient who can no longer perform bimanual skills may benefit from a device to help manipulate buttons in order to dress independently. The occupational therapist can work with the patient and maximize his/her capabilities in performing activities of daily living (ADL). The occupational therapist also can engage the patient in a sensory and motor re-education program if there is impaired function in the hand.

Speech Therapy

Though not directly related to plexopathies, metastatic neoplasm also may alter communication, swallowing, or cognitive function, requiring a speech therapy consultation.

Recreational Therapy

Recreational therapy can help to maintain the patient's interest and skills by incorporating leisure time activities into the rehabilitation program.

Medical Issues/Complications

For more severe lesions, an interdisciplinary approach may be most effective, including prescription of physical, occupational, and recreational therapies. Coordination of therapies, consultants, complications, and medications is needed. Treatment often is difficult and may be palliative; chemotherapy and radiation therapy (up to 50% of patients obtain significant pain relief) are used if the tumor is sensitive to them. As the disease progresses, adequate pain control is the most important goal as most patients succumb to neoplastic involvement of vital organs within a few years.

Surgical Intervention

Several authorities advise referral of patients with NBP to surgeons with special expertise in treatment of NBP. Accurate diagnosis may prevent unnecessary surgery for carpal tunnel syndrome or thoracic outlet syndrome. Surgery usually is performed only for definite tissue diagnosis in secondary neoplasms. Primary tumors, like benign schwannomas, are encapsulated, permitting surgical excision without sacrificing adjacent nerves.

Most solitary neurofibromas can be resected without producing or increasing deficit, but this procedure is more difficult than excision of encapsulated tumors and usually requires magnification, intraoperative nerve action potential recording, and sometimes cable grafts. Some neurofibromas are "dumbbell tumors" that extend into the epidural space. Many benign tumors (including neurofibromas) can be removed without significant loss using surgical loupes or microscope and repetitive NAP recording. Plexiform neuromas are more difficult to remove because of extensive segments of nerve fiber involvement. Some elements may have to be sacrificed for pain control and to save the remainder of the plexus. In patients with severe intractable pain, dorsal rhizotomy, dorsal root entry zone surgery, or high contralateral percutaneous cordotomies can be considered. Amputation and other destructive procedures often are ineffective.

Consultations

Most patients have a consulting oncologist, as well as an internist or family practitioner. Some patients may need an anesthesiologist or interventional physiatrist for injections, and some may have seen a neurologist, or less commonly, a neurosurgeon (for more drastic measures mentioned above). Consultation with a psychologist may be helpful in terms of emotional adjustment, pain control, and supportive counseling.

Other Treatment

Paravertebral nerve blocks or other injection procedures may be indicated, depending on the location of the tumor(s). NBP often is widespread and is not amenable to application of selective blocks.

Medication

No medications are specific for this diagnostic entity. Typical analgesic and adjunct analgesic agents may be worthwhile in managing neoplastic plexopathy.

Opioid analgesics (eg, long-acting oxycodone or fentanyl) are associated with fewer concerns about tolerance and dependency than many other opiates. A ceiling effect is also absent with these agents, while use of combination agents like hydrocodone/acetaminophen may be limited by maximum dose of acetaminophen allowable (4 g/d). Opiates may be effective at acceptable doses and often are tried first. For more mild symptoms, topical analgesics should be tried.

Nonsteroidal anti-inflammatory drugs (NSAIDs) can be helpful and usually are tried in conjunction with other agents.

Adjunct agents such as tricyclic antidepressants (eg, nortriptyline, amitriptyline) or other antidepressants (eg, sertraline, venlafaxine), anticonvulsants (Lyrica, gabapentin, Tegretol), and, less commonly, antiarrhythmics (eg, mexiletine) may be used for control of neuropathic pain.

Opioid analgesic agents

Should be used early in the disease. As in most painful conditions, begin with low potency medications at low doses and taper to desired response.

Hydrocodone and acetaminophen (Vicodin, Lortab, Norcet)

Drug combination indicated for moderate to severe pain.

Dosing

Adult

1-2 tab PO q4-6h prn; not to exceed 4 g/d acetaminophen

Pediatric

Not established

Interactions

Coadministration with phenothiazines may decrease analgesic effects; toxicity increases with CNS depressants or tricyclic antidepressants

Contraindications

Documented hypersensitivity, high altitude cerebral edema (HACE), or elevated intracranial pressure (ICP)

Precautions

Pregnancy

C - Safety for use during pregnancy has not been established.

Precautions

Tablets contain metabisulfite, which may cause hypersensitivity; caution in patients dependent on opiates since this substitution may result in acute opiate-withdrawal symptoms; caution in severe renal or hepatic dysfunction

Oxycodone (OxyContin)

Indicated for the relief of moderate to severe pain.

Dosing

Adult

10 mg PO bid

Pediatric

Not established

Interactions

Phenothiazines may antagonize analgesic effects; MAOIs, general anesthesia, CNS depressants, and tricyclic antidepressants may increase toxicity

Contraindications

Documented hypersensitivity

Precautions

Pregnancy

B - Usually safe but benefits must outweigh the risks.

Precautions

Pregnancy category D if used for prolonged periods or in high doses; caution in COPD, emphysema, and renal insufficiency

Fentanyl (Duragesic)

Potent opioid analgesic with much shorter half-life than morphine sulfate. DOC for conscious sedation analgesia.
Excellent choice for pain management and sedation with short duration (30-60 min) and easy to titrate. Easily and quickly reversed by naloxone.

Dosing

Adult

25 mcg/h transdermal system q72h
After initial dose, subsequent doses should not be titrated more frequently than q3h or q6h thereafter
When using transdermal dosage form, most patients are controlled with 72 h dosing intervals; some patients require dosing intervals of 48 h

Pediatric

Not established

Interactions

Phenothiazines may antagonize analgesic effects of opiate agonists; tricyclic antidepressants may potentiate adverse effects of fentanyl when both drugs are used concurrently

Contraindications

Documented hypersensitivity; hypotension or potentially compromised airway where it would be difficult to establish rapid airway control

Precautions

Pregnancy

C - Safety for use during pregnancy has not been established.

Precautions

Caution in hypotension, respiratory depression, constipation, nausea, emesis, and urinary retention; idiosyncratic reaction, known as chest wall rigidity syndrome, may require neuromuscular blockade in order to increase ventilation; do not use in opioid naive patients

Corticosteroids

Can be helpful since inflammation may be part of the pathophysiology of the pain of NBP, as previously mentioned.

Prednisone (Deltasone, Orasone, Meticorten)

May decrease inflammation by reversing increased capillary permeability and suppressing PMN activity.

Dosing

Adult

60 mg/d PO; taper quickly over 5-12 d

Pediatric

0.05-2 mg/kg/d PO; taper quickly over 5-12 d

Interactions

Coadministration with estrogens may decrease prednisone clearance; concurrent use with digoxin may cause digitalis toxicity secondary to hypokalemia; phenobarbital, phenytoin, and rifampin may increase metabolism of glucocorticoids (consider increasing maintenance dose); monitor for hypokalemia with coadministration of diuretics

Contraindications

Documented hypersensitivity, GI disease, viral infection, peptic ulcer disease, hepatic dysfunction, connective tissue infections, and fungal or tubercular skin infections

Precautions

Pregnancy

B - Usually safe but benefits must outweigh the risks.

Precautions

Abrupt discontinuation of glucocorticoids may cause adrenal crisis; hyperglycemia, edema, osteonecrosis, myopathy, peptic ulcer disease, hypokalemia, osteoporosis, euphoria, psychosis, myasthenia gravis, growth suppression, and infections may occur with glucocorticoid use

Cyclooxygenase-2 (COX-2) inhibitors

Although increased cost can be a negative factor, the incidence of costly and potentially fatal GI bleeds is clearly less with COX-2 inhibitors than with traditional NSAIDs. Ongoing analysis of cost avoidance of GI bleeds will further define the populations that will find COX-2 inhibitors the most beneficial.

Celecoxib (Celebrex)

Inhibits primarily COX-2. COX-2 is considered an inducible isoenzyme, induced during pain and inflammatory stimuli. Inhibition of COX-1 may contribute to NSAID GI toxicity. At therapeutic concentrations, COX-1 isoenzyme is not inhibited; thus, GI toxicity may be decreased. Seek lowest dose for each patient.

Dosing

Adult

100 mg PO qd

Pediatric

Not established

Interactions

Coadministration with fluconazole may cause increase plasma concentrations because of inhibition of celecoxib metabolism; coadministration with rifampin may decrease plasma concentrations

Contraindications

Documented hypersensitivity

Precautions

Pregnancy

C - Safety for use during pregnancy has not been established.

Precautions

Category D in third trimester of pregnancy; may cause fluid retention and peripheral edema; caution in compromised cardiac function, hypertension, conditions predisposing to fluid retention; severe heart failure and hyponatremia because may deteriorate circulatory hemodynamics; NSAIDs may mask usual signs of infection; caution in the presence of existing controlled infections; evaluate symptoms and signs suggesting liver dysfunction or in abnormal liver lab results

Nonsteroidal anti-inflammatory drugs

Have analgesic, anti-inflammatory, and antipyretic activities. Their mechanism of action is not known, but they may inhibit cyclo-oxygenase activity and prostaglandin synthesis. Other mechanisms may exist as well, such as inhibition of leukotriene synthesis, lysosomal enzyme release, lipoxygenase activity, neutrophil aggregation, and various cell-membrane functions. Inexpensive older NSAIDs like ibuprofen or naproxen may be considered; however, COX-2 inhibitors with their lower GI toxicity are often first-line agents.

Ibuprofen (Motrin, Ibuprin)

DOC for patients with mild to moderate pain. Inhibits inflammatory reactions and pain by decreasing prostaglandin synthesis.

Dosing

Adult

200 mg PO qid

Pediatric

Not established

Interactions

Coadministration with aspirin increases risk of inducing serious NSAID-related side effects; probenecid may increase concentrations and, possibly, toxicity of NSAIDs; may decrease effect of hydralazine, captopril, and beta-blockers; may decrease diuretic effects of furosemide and thiazides; may increase PT when taking anticoagulants (instruct patients to watch for signs of bleeding); may increase risk of methotrexate toxicity; phenytoin levels may be increased when administered concurrently

Contraindications

Documented hypersensitivity, peptic ulcer disease, recent GI bleeding or perforation, renal insufficiency, and high risk of bleeding

Precautions

Pregnancy

B - Usually safe but benefits must outweigh the risks.

Precautions

Category D in third trimester of pregnancy; caution in congestive heart failure, hypertension, and decreased renal and hepatic function; caution in coagulation abnormalities or during anticoagulant therapy

Naproxen (Naprosyn, Naprelan, Anaprox)

For relief of mild to moderate pain; inhibits inflammatory reactions and pain by decreasing activity of cyclo-oxygenase, which results in a decrease of prostaglandin synthesis.

Dosing

Adult

250 mg PO bid

Pediatric

Not established

Interactions

Coadministration with aspirin increases risk of inducing serious NSAID-related side effects; probenecid may increase concentrations and, possibly, toxicity of NSAIDs; may decrease effect of hydralazine, captopril, and beta-blockers; may decrease diuretic effects of furosemide and thiazides; may increase PT when taking anticoagulants (instruct patients to watch for signs of bleeding); may increase risk of methotrexate toxicity; phenytoin levels may be increased when administered concurrently

Contraindications

Documented hypersensitivity; peptic ulcer disease; recent GI bleeding or perforation; renal insufficiency

Precautions

Pregnancy

B - Usually safe but benefits must outweigh the risks.

Precautions

Category D in third trimester of pregnancy; acute renal insufficiency, interstitial nephritis, hyperkalemia, hyponatremia, and renal papillary necrosis may occur; patients with preexisting renal disease or compromised renal perfusion risk acute renal failure; leukopenia occurs rarely, is transient, and usually returns to normal during therapy; persistent leukopenia, granulocytopenia, or thrombocytopenia warrants further evaluation and may require discontinuation of drug

Tricyclic antidepressants

A complex group of drugs that have central and peripheral anticholinergic effects, as well as sedative effects. They have central effects on pain transmission and block the active reuptake of norepinephrine and serotonin.

Amitriptyline (Elavil)

Analgesic for certain chronic and neuropathic pain. Used as adjunct therapy.

Dosing

Adult

10-100 mg/d PO hs

Pediatric

Not established

Interactions

Phenobarbital may decrease effects; coadministration with CYP2D6 enzyme system inhibitors (eg, cimetidine, quinidine) may increase levels; inhibits hypotensive effects of guanethidine; may interact with thyroid medications, alcohol, CNS depressants, barbiturates, and disulfiram

Contraindications

Documented hypersensitivity; patient has taken MAOIs in past 14 d; history of seizures, cardiac arrhythmias, glaucoma, and urinary retention

Precautions

Pregnancy

D - Unsafe in pregnancy

Precautions

Caution in cardiac conduction disturbances and history of hyperthyroidism, renal or hepatic impairment; avoid using in elderly patients

Nortriptyline (Pamelor, Aventyl HCl)

Used as adjunct therapy. Has demonstrated effectiveness in the treatment of chronic pain. Used as adjunct agent.
By inhibiting the reuptake of serotonin and/or norepinephrine by the presynaptic neuronal membrane, this drug increases the synaptic concentration of these neurotransmitters in the CNS.
Pharmacodynamic effects such as the desensitization of adenyl cyclase and down-regulation of beta-adrenergic receptors and serotonin receptors also appear to play a role in its mechanisms of action.

Dosing

Adult

10 mg PO tid/qid up to 150 mg/d

Pediatric

25-35 kg: 10-20 mg/d PO
35-54 kg: 25-35 mg/d PO

Interactions

Cimetidine may increase levels when used concurrently; may increase PT in patients stabilized with warfarin

Contraindications

Documented hypersensitivity; narrow-angle glaucoma; do not administer to patients who have taken MAOIs in past 14 d

Precautions

Pregnancy

D - Unsafe in pregnancy

Precautions

Cimetidine may increase nortriptyline levels when used concurrently; nortriptyline may increase PT in patients stabilized with warfarin

Anticonvulsants

Use of certain antiepileptic drugs, such as the GABA analogue Neurontin (gabapentin), has proven helpful in some cases of neuropathic pain. Have central and peripheral anticholinergic effects, as well as sedative effects, and block the active reuptake of norepinephrine and serotonin. The multifactorial mechanism of analgesia could include improved sleep, altered perception of pain, and increase in pain threshold. Rarely should these drugs be used in treatment of acute pain, since a few weeks may be required for them to become effective.

Carbamazepine (Tegretol)

May reduce polysynaptic responses and block post-tetanic potentiation. Used as adjunct therapy.

Dosing

Adult

100 mg PO bid on first day and increase by 200 mg/d with 100-mg increments PO q12h prn; not to exceed 1200 mg/d

Pediatric

<12 years: Not established
>12 years: Administer as in adults

Interactions

Serum levels may increase significantly within 30 days of danazol coadministration (avoid whenever possible); do not coadminister with MAOIs; cimetidine may increase toxicity especially if taken in first 4 wk of therapy; carbamazepine may decrease primidone and phenobarbital levels (their coadministration may increase carbamazepine levels)

Contraindications

Documented hypersensitivity; history of bone marrow depression; administration of MAOIs within last 14 d

Precautions

Pregnancy

D - Unsafe in pregnancy

Precautions

Do not use to relief minor aches or pains; caution with increased intraocular pressure; obtain CBC counts and serum iron baseline prior to treatment, during first 2 months, and yearly or every other year thereafter; can cause drowsiness, dizziness, and blurred vision; caution while driving or performing other tasks requiring alertness

Gabapentin (Neurontin)

Has anticonvulsant properties and antineuralgic effects; however, exact mechanism of action is unknown. Structurally related to GABA but does not interact with GABA receptors. There are no firm rules, but, in elderly patients, less potentially anticholinergic medications like gabapentin may be a good first choice. Used as adjunct therapy.

Dosing

Adult

Day 1: 100 mg tid or 300 mg hs
Day 2: 400 mg PO tid over 3 d and titrate prn; not to exceed 1200 mg PO qid
Titration to effect can take place over several days (300 mg on day 1, 300 mg bid on day 2, and 300 mg tid on day 3)

Pediatric

Not established

Interactions

Antacids may reduce bioavailability of gabapentin significantly (administer at least 2 h following antacids); may increase norethindrone levels significantly

Contraindications

Documented hypersensitivity

Precautions

Pregnancy

C - Safety for use during pregnancy has not been established.

Precautions

Caution in severe renal disease

Follow-up

Further Inpatient Care

• Further inpatient care is needed if more invasive procedures are performed or if medical complications need to be monitored during radiation or chemotherapy.

Further Outpatient Care

• Routine follow-up care is necessary for monitoring the patient's condition and titrating medications.

Complications

• Potential complications of NBP include rapid progression of symptoms with disabling pain, edema, muscle contractures, or bony deformities. Most patients with secondary neoplasms succumb to metastatic involvement of vital organs within a few years.

Prognosis

• Most patients with benign primary neoplasms have a good prognosis, while patients with malignant primary neoplasms have a less favorable prognosis, regardless of therapy performed. For secondary neoplasms, most patients succumb to death within a few years from metastases to vital organs. On the other hand, preservation of some function and provision of adequate analgesia may be realistic goals for many patients.

Patient Education

• See the Rehabilitation Program section above.

Miscellaneous

Medicolegal Pitfalls

• Accuracy and promptness of the diagnosis of NBP facilitate patient care and reduce the risk of litigation.

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Keywords

brachial plexus tumors, neoplasms of the brachial plexus, metastatic brachial plexopathy, neoplastic brachial palsy

Contributor Information and Disclosures

Author

Mark A Wren, MD, MPH, Medical Director, Department of Physical Medicine and Rehabilitation, HealthSouth Rehabilitation Hospital of Texarkana
Mark A Wren, MD, MPH is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation, American Association of Neuromuscular and Electrodiagnostic Medicine, American Medical Association, and Texas Medical Association
Disclosure: none None None

Medical Editor

Robert J Kaplan, MD, Associate Professor, Department of Physical Medicine and Rehabilitation, University of Kansas School of Medicine and Medical Center
Robert J Kaplan, MD is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation, American Association of Neuromuscular and Electrodiagnostic Medicine, Association of Academic Physiatrists, International Spine Intervention Society, and Physiatric Association of Spine, Sports and Occupational Rehabilitation
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.

Managing Editor

Michael T Andary, MD, MS, Residency Program Director, Associate Professor, Department of Physical Medicine and Rehabilitation, Michigan State University College of Osteopathic Medicine
Michael T Andary, MD, MS is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation, American Association of Neuromuscular and Electrodiagnostic Medicine, American Medical Association, and Association of Academic Physiatrists
Disclosure: Nothing to disclose.

CME Editor

Kelly L Allen, MD, Consulting Staff, Department of Physical Medicine and Rehabilitation, Lourdes Regional Rehabilitation Center, Our Lady of Lourdes Medical Center
Disclosure: Nothing to disclose.

Chief Editor

Robert H Meier III, MD, Director, Amputee Services of America, Presbyterian St Luke's Hospital; Consulting Staff, North Valley Rehabilitation Hospital, Kindred Hospital, and North Suburban Hospital
Robert H Meier III, MD is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation and Association of Academic Physiatrists
Disclosure: Nothing to disclose.

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