Brachial plexitis causes and differential and foils

Avulsions occur with traction injuries and may be overlooked in patients with multi-trauma.

Clavicle fractures can injure the plexus through bone fragments or hematomas, scar tissue (in a healed fracture) or development of a subclavian pseudoaneurysm.

Stingers and burners (See separate post http://emgnotes.blogspot.com/2007/04/traunmatic-neuropathy-stingers.html ). Compression of the upper brachial plexus may occur between the shoulder pad and upper medial scapula and may be prevented with an orthosis (Markey et al, 1993, Am J Sports Med). Lesion can also be in the ventral rami, cord, roots or cervical cord but in professional players is more likely to be spinal stenosis .

Intraoperative plexopathy of brachial plexus can be due to hyperabduction of the relaxed arm, plexitis (autoimmune) following surgery, during median sternotomy such as CABG (5-7 % of time) which can mimic an ulnar neuropathy, with variable locale and severity. It can occur with traction on the plexus during wide sternotomy, during jugular cannulation, and is tenfold higher when the internal mammary artery is used for bypass grafting. Forceful traction can also fracture the first rib that then can cause plexopathy. Upper trunk damage can occur if the patient is held head down and the arm is abducted simultaneously.

Acute compression occurs with coma, or carrying heavy backpacks causing a bilateral syndrome especially affecting serratia anterior.

Hematomas during axillary angiograms can cause blood leak at edge of pectoralis muscle and recovery IF blood is removed rapidly. False aneurysms can occur years after trauma to plexus, median or radial nerve.

Newborns do not have a falling incidence of brachial plexus injury (0.05-0.3 % births) with Erb's being most common (weak shoulder abduction and elbow flexion), Klumpke's less common.

Malignant plexopathy is most often due to cancer of lung, breast, or lymphoma, rarely early except in the Pancoast tumor syndrome. It usually presents with shoulder pain radiating down the arm (medial most often) followed by paresthesias and weakness. The differential includes radiation plexopathy, intraoperative plexus trauma, and unrelated brachial plexitis.

Pancoast syndrome due to tumor at apex of the lung causes pain down inner arm with two thirds developing Horner's syndrome, and one third, weakness and sensory changes in lower trunk distribution.

Primary tumors of brachial plexus include neurofibromas (often/usually plexiform) with pain, supraclavicular mass, and mild neurologic deficit. Schwannomas with "dumbbell" lesions and sensory symptoms withouu deficit. Intraneural perineurioma (or localized hypertrophic neuropathy) presents with slowly progressive upper limb deficits. Malignant nerve tumors are rare.

Radiation plexitis can occur within 26 years of radiation of the plexus and presents with sensory and motor signs and swelling. Horner's occurs less frequently than in malignant plexitis but it can happen. Radiation is commonly, but not universally thought to be more likely to affect the upper trunk. It may be relentlessly progressive and lead to a useless arm. Occassionally it may stop or respond to PT or OT.

Radiation can also cause malignant nerve sheath tumors with painful enlarging mass and dysfunction. Ischemic plexitis can occur due to radiation induced segmental occlusion of the subclavian artery.

Thoracic outlet syndromes are discussed in another post.

Parsonage-Turner syndrome causes pain then weakness. It may mimic a shoulder joint lesion.

Hereditary neuropathy with liability to pressure palsies (HNPP) often affects the brachial plexus.

Patients with plexitis due to diabates have a subacute onset and good recovery. Plexitis in heroin addicted patients has less severe pain, and involvement of the lower part of the plexus.