THE CLINICAL SYNDROME

• The signs and symptoms of thoracic outlet syndrome include tingling sensations and aching pain in the neck, shoulder, and arm.

• This syndrome is characterized by a constellation of signs and symptoms.

• The compression of the brachial plexus as well as the subclavian artery and vein as they travel through the interscalene triangle, the costoclavicular space, and the subpectoral (subcoracoid) tunnel is thought to be the cause of the condition.

• Because the plexus cords, subclavian/axillary artery, and the terminal branches of the brachial plexus travel through the subpectoral space, congenitally abnormal structures, such as cervical ribs, aberrant scalene muscles, fibrous bands, and/or abnormal pectoralis minor and subscapularis muscles, can cause compression or entrapment of the neurovascular structures.

• This can result in damage to the neurovascular structures.

• When evaluating a patient for thoracic outlet syndrome, it is imperative that both cervicothoracic tumors and aneurysms be taken into consideration.

• Because any one or all of the structures could be compressed, the clinical manifestation of the syndrome could take on many different forms.

• The age range of 25 to 50 years old is the one in which women are diagnosed with thoracic outlet syndrome the most frequently.

• It has been the focus of a substantial amount of discussion, and both the diagnosis and the treatment of thoracic outlet syndrome continue to be contentious topics.

SIGNS AND SYMPTOMS

• Compression of neural structures is responsible for the majority of the symptoms of thoracic outlet syndrome, which can manifest in a variety of ways.

• It is possible to make an incorrect diagnosis of tardy ulnar palsy in patients who have paresthesias of the upper extremity that radiate into the distribution of the ulnar nerve.

• Aching and a lack of coordination in the extremity that is affected are also typical findings.

• In the event that the pain continues, an abnormal position of the shoulder girdle may be observed in an effort to release compression or entrapment of the neurovascular structures.

• In the event that there is vascular compression, edema or discoloration of the arm may be observed.

• In extremely rare cases, venous or arterial thrombosis may take place.

• Sometimes the symptoms of thoracic outlet syndrome are brought on by an arterial aneurysm, which can be diagnosed by listening for a bruit in the region around the supraclavicular area of the chest.

TESTING

• When a patient is suspected of having thoracic outlet syndrome, plain radiographs of the cervical spine should be obtained.

• It is important to carefully examine these films in order to identify any congenital abnormalities, such as cervical ribs or excessively extended transverse processes.

• Chest radiography that includes apical lordotic views should also be performed on patients in order to rule out Pancoast's tumor.

• The cervical spine should be scanned with magnetic resonance imaging (MRI) in order to identify lesions of the cervical spinal cord and exiting nerve roots, as well as cervical ribs and fibrous adhesions.

• If the diagnosis is still in question, an MRI of the brachial plexus should be performed to look for any hidden pathological processes.

• These processes can include primary tumors of the plexus as well as aberrant scalene muscles, both of which have the potential to cause compression or entrapment.

• The diagnosis might also be clarified with the help of ultrasonography.

• In order to rule out other potential causes of the patient's pain, a screening battery of laboratory tests, including a complete blood count, erythrocyte sedimentation rate, testing for antinuclear antibodies, and automated blood chemistry, may be carried out.

DIFFERENTIAL DIAGNOSIS

• Diseases of the bony cervical spine, the cervical disk, and the cervical spinal cord can all present symptoms similar to those of thoracic outlet syndrome.

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

• Appropriate testing, such as an MRI and electromyography, can help sort through the myriad of possibilities, but the clinician should also be aware of this fact.

• There is a possibility that syringomyelia, a tumor of the cervical spinal cord, and a tumor of the cervical nerve root as it exits the spinal cord (for example, schwannoma) can have a gradual onset and be challenging to diagnose.

• In cases where there is no evidence of clear antecedent trauma, particularly those in which the patient has a history of tobacco use, Pancoast's tumor ought to be placed high on the list of diagnostic possibilities.

• Consideration should also be given to the possibility of a herniated cervical disk laterally, a metastatic tumor, or cervical spondylosis if these conditions cause significant nerve root compression.

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

TREATMENT

Physical Modalities

• Physical therapy is the primary treatment option for patients who are diagnosed with thoracic outlet syndrome.

• The goal of this treatment is to maintain function while also providing pain relief.

• Shoulder abnormalities, such as subluxation and adhesive capsulitis, need to be treated with a great deal of intensity.

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

Drug Therapy

Gabapentin

• The neuritic pain associated with thoracic outlet syndrome is typically treated pharmacologically with gabapentin as an initial course of action.

• The initial dose of gabapentin is 300 milligrams taken before going to bed for a period of two nights.

• The patient should be warned about the possibility of experiencing adverse effects, such as dizziness, sedation, confusion, and rash.

• After that, the dosage of the medication is raised by 300 milligrams at a time, twice daily, in doses that are equally divided, as long as the patient's tolerance for the drug's side effects remains stable, up to a total of 2400 milligrams per day.

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

• This is done in the event that the patient has experienced some relief from their pain.

• It is extremely rare for a daily dose to be required that is higher than 3600 mg.

Carbamazepine

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

• Confusion and anxiety have been surrounding the use of carbamazepine despite the fact that it is both safe and effective.

• The medication is sometimes withdrawn from the market because of laboratory abnormalities that are incorrectly blamed on it.

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

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

Invasive Therapy

Brachial Plexus Block

• An excellent complementary treatment for thoracic outlet syndrome is a brachial plexus block, which consists of the administration of a local anesthetic and steroid.

• During the process of titrating medications to their optimal levels, this technique provides rapid pain relief.

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

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

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

Surgery

• In cases where there is no evidence of disease (such as in the case of a cervical rib), surgical treatment for thoracic outlet syndrome almost never results in a positive outcome.

• This is true regardless of the approach that is taken.

• However, in patients who have a discernible cause for their symptoms but have not found relief from more conservative therapies, the prudent application of surgical treatment may be a reasonable last step.

COMPLICATIONS AND PITFALLS

• It can be challenging to find relief from the discomfort and dysfunction caused by thoracic outlet syndrome.

• In any treatment plan that has been carefully considered, physical therapy should serve as the primary modality.

• Opioid analgesics are not effective at treating the pain associated with thoracic outlet syndrome; therefore, you should avoid taking these medications.

• It is possible that the patient will be able to participate in physical therapy if they make careful use of adjuvant analgesics, which help to palliate the pain.

• The plexopathy that is caused by a tumor or an avulsion of the cervical roots requires aggressive treatment.

• Stretch injuries and contusions of the plexus may respond with time, but plexopathy that is caused by other causes is crucial to correctly diagnose.