THE CLINICAL SYNDROME

• The shoulder, the supraclavicular region, and the upper extremities can all be affected by brachial plexopathy, which is a group of symptoms consisting of neurogenic pain and accompanying weakening that radiates from the area of the shoulder.

• Some of the more common causes of brachial plexopathy include compression of the plexus by cervical ribs or abnormal muscles (such as in the case of thoracic outlet syndrome), invasion of the plexus by tumor (such as in the case of Pancoast's tumor syndrome), direct trauma to the plexus (such as in the case of stretch injuries and avulsions), inflammatory causes (such as in the case of Parsonage-Turner syndrome, herpes zoster.

SIGNS AND SYMPTOMS

• Patients who are affected by brachial plexopathy often describe experiencing discomfort that extends from the supraclavicular region to the upper extremities.

• The pain has the characteristic of being neurotic and may acquire a penetrating and unrelenting nature when the plexus is consumed by malignancy.

• Because movement of the neck and shoulders makes the discomfort worse, patients typically try to avoid movements that involve those areas.

• Frozen shoulder is a common complication that might make the diagnosis more difficult.

• The Adson test is one that can be done when there is a suspicion of thoracic outlet syndrome.

• A good result indicates that the radial pulse was absent when the patient's neck was stretched and their head was moved toward the unaffected side of their body.

• The Adson test is a general screening tool; therefore, treatment decisions should not be based solely on the results of this test (see Testing).

• It is important to evaluate brachial plexitis if the patient arrives with extreme discomfort, which is then quickly followed by deep weakness.

• Electromyography can be used to confirm the diagnosis of brachial plexitis.

TESTING

• The magnetic resonance imaging (MRI) of the cervical spine and the brachial plexus should be performed on all patients who arrive with brachial plexopathy.

• This is especially important for individuals who do not have a clear history of any prior trauma to the area.

• If an MRI cannot be performed, other imaging methods such as computed tomography (CT) scanning and ultrasound imaging could be used instead.

• Electromyography and the measuring of nerve conduction velocity are particularly sensitive diagnostic tools, and an experienced electromyographer may determine which part of the plexus is dysfunctional using these tools.

• Serial electromyography is recommended when an inflammatory etiology for the plexopathy is suspected.

• MRI of the shoulder muscles frequently indicates muscle edema in addition to denervation-induced atrophy.

• If a tumor of the brachial plexus, such as Pancoast's tumor or another type of brachial plexus tumor, is suspected, chest radiographs with apical lordotic views may be of assistance.

• In the event that the diagnosis is uncertain, screening laboratory tests, which include a complete blood count, erythrocyte sedimentation rate, antinuclear antibody testing, and automated blood chemistry, should be carried out in order to eliminate other potential reasons for the patient's pain.

DIFFERENTIAL DIAGNOSIS

• Brachial plexopathy can be confused with conditions that affect the cervical spinal cord, the bony cervical spine, or the disks.

• The clinician should be aware that more than one pathologic process may be contributing to the patient's symptoms.

• Appropriate testing, such as magnetic resonance imaging (MRI), computed tomography (CT), ultrasonography (US), and electromyography (EMG), can help sort through the myriad of possibilities.

• The symptoms of syringomyelia, a tumor of the cervical spinal cord, and a tumor of the cervical nerve root as it exits the spinal cord (such as schwannoma) can appear gradually over time and can be challenging to diagnose.

• Patients who present with brachial plexopathy but have no obvious history of trauma should have Pancoast's tumor at the top of their list of possible diagnoses.

• This is especially true if the patient has a past of cigarette smoking.

• Brachial plexopathy can also be caused by a lateral ruptured cervical disk, a metastatic tumor, or cervical spondylosis that results in substantial nerve root compression.

• In extremely rare cases, an infection that affects the tip of the lung might cause the plexus to become compressed and irritated.

TREATMENT

Drug Therapy

Gabapentin

• The neuritic pain associated with brachial plexopathy is typically treated with gabapentin as an initial course of treatment.

• Begin treating the patient with 300 milligrams of gabapentin before bedtime for the first two nights.

• Warn the patient about the potential adverse effects of the medication, which may include dizziness, drowsiness, confusion, and rash.

• The dose of the medication is then gradually increased by 300 milligrams over the course of two days, with each day's total dose being divided evenly into the previous day's dose.

• This process is repeated until either pain relief is achieved or a total dose of 2400 milligrams per day is attained.

• At this stage, blood values are tested, and the medication is carefully titrated upward using 100-mg tablets.

• This is done in the event that the patient has received some relief from their discomfort.

• It is quite uncommon for a daily dose to be more than 3600 mg.

Pregabalin

• Pregabalin is an acceptable alternative to gabapentin, and some people find that it is better tolerated than gabapentin.

• The typical starting dose of pregabalin is 50 milligrams taken three times a day.

• This dose can be increased to a maximum of 100 milligrams taken three times a day if the patient's side effects permit.

• Patients whose kidney function is affected should have their dosage of pregabalin lowered.

• The kidneys are the primary organs responsible for excreting the drug.

Carbamazepine

• Patients who may not experience relief from the effects of gabapentin may benefit from taking carbamazepine.

• The usage of carbamazepine has been surrounded with confusion and worry despite the fact that it is both safe and effective.

• Because of erroneous laboratory abnormalities that have been attributed to it, it is sometimes taken off the market.

• Before beginning treatment with the medication, it is necessary to collect baseline laboratory values.

• These should include a full blood count, a chemistry profile generated by an automated system, and a urinalysis.

• If the pain is not out of control, you should begin treatment with carbamazepine gradually, at a starting dose of between 100 and 200 milligrams at bedtime for the first two nights.

• A warning should be given to the patient about potential adverse reactions, such as lightheadedness, drowsiness, disorientation, and rashes.

• If the patient's tolerance to the drug's side effects permits, the dosage of the medication is gradually increased by 100–200 milligrams (mg) every two days until either pain relief is achieved or a daily total dose of 1200 mg is reached.

Baclofen

• Baclofen could be beneficial for certain people who are unable to get relief from their symptoms with the help of gabapentin or carbamazepine.

• Before beginning treatment with baclofen, baseline laboratory tests should be performed, and the patient should be warned about the possible side effects, which are the same as those associated with carbamazepine and gabapentin.

• Baseline laboratory testing should also be performed.

• Baclofen treatment begins with a single dose of 10 milligrams taken before going to bed for two consecutive nights.

• After that, the dosage is increased by 10 milligrams over the course of seven days, with each increase being given in doses that are equally divided.

• This continues until pain relief is achieved or the maximum daily dosage of 80 milligrams is reached.

• This medication is known to cause serious adverse effects on the liver and the central nervous system, including lethargy and sedation.

• In the same vein as with carbamazepine, it is recommended to carefully monitor the values obtained from the laboratory.

Invasive Therapy

Brachial Plexus Block

• An excellent complement to medication treatment is a brachial plexus block, which consists of the administration of a local anesthetic as well as steroid.

• During the process of titrating drugs to their optimal levels, this approach provides quick pain relief.

• The initial block is performed using bupivacaine that does not include any preservatives in conjunction with methylprednisolone.

• The following daily nerve blocks are performed in a manner quite identical to the first one, with the exception that a lower amount of methylprednisolone is used.

• This method can also be utilized to control pain that hasn't fully settled in.

Radiofrequency Destruction of the Brachial Plexus

• Using biplanar fluoroscopic guidance, a radiofrequency lesion can be created to damage the brachial plexus, which will result in its destruction.

• Patients who have not responded to any of the aforementioned treatments and whose discomfort is the result of a tumor or an avulsion of the brachial plexus are the only ones who are eligible for this procedure.

Dorsal Root Entry Zone Lesioning

• Patients with intractable brachial plexopathy who have not responded to any of the aforementioned treatments and whose pain is caused by a tumor or avulsion of the brachial plexus are candidates for the neurosurgical procedure known as dorsal root entry zone lesioning.

• This is the procedure of choice for treating intractable brachial plexopathy.

• This is a large neurosurgical operation, and there are significant dangers associated with it.

Physical Modalities

• Patients who are suffering from brachial plexopathy should participate in both physical and occupational therapy in order to keep their function and reduce their level of discomfort as part of their treatment plan.

• Shoulder problems, such as subluxation and adhesive capsulitis, require rigorous treatment.

• This treatment is necessary.

• It is essential to participate in occupational therapy to receive assistance with activities of daily life if one wishes to forestall a further decline in function.

COMPLICATIONS AND PITFALLS

• Brachial plexopathy is a painful condition that is difficult to treat.

• It has a poor response to opioid analgesics and may also have a poor response to the drugs that have been addressed.

• Patients suffering from brachial plexopathy who are unable to regulate their discomfort should seriously consider being hospitalized.

• Suicide is a risk associated with this condition.

• Because stretch injuries and contusions of the plexus may respond with time, but plexopathy secondary to tumor or avulsion of the cervical roots requires aggressive treatment, it is crucial to correctly diagnose the underlying cause of the pain and dysfunction associated with brachial plexopathy for the successful treatment of the pain and dysfunction associated with brachial plexopathy.