.jpg)
Brachial Neuritis
Definition: A chemical or mechanical irritation of one or more of the nerves comprising the brachial plexus.
Causes: There are numerous causes of brachial plexus neuritis.
1) Mechanical stressors of brachial irritation include traction pathologies such Klumpke's or Erb's paralysis; most commonly a result of traumatic vaginal delivery. Other mechanical causes of brachial neuritis include cervical ribs and/or elongated C7 transverse processes. The neurovascular bundle exiting the cervical spine and thoracic outlet can also be compressed by the scalene muscles, a hypertonic pectoralis minor muscle, a pancoast tumour (this will primarily affect the sympathetic chain), an elevated first rib, a depressed or fractured clavicle, and a spasm of the subclavius muscle.
2) Chemical irritation may be a progression from mechanical, or can be a result of more systemic conditions.
Examination: A patient suffering from brachial neuritis will commonly present with neurological symptoms of varying intensity along the affected dermatome(s). The nerves affected by brachial neuritis will dictate the distribution and presentation of this condition. In advanced stages, muscular atrophy, hyporeflexia, hypotonia, fasciculations, and asthenia may be appreciated over the affected area(s). It is important to rule out any apical lung mass, cardiogenic referral, and CNS involvement.
Observation: Look out for signs of lower motor neuron lesion as described above. Determine the areas affected by neurological changes to elucidated which nerve(s) is/are affected.
Orthopaedic tests for brachial neuritis:
Bakody's sign: Instruct the patient to interlace their fingers and rest their hands on their head. Reduce symptoms indicate a positive test.
Tinnel test: Percuss the brachial plexus as it exits the cervical spine. An aggravation in symptoms is a positive.
Brachial plexus stretch test: With the patient seated, instruct them to side bend their head away from the symptomatic side and extend the shoulder and elbow on the symptomatic side. Aggravation in symptoms is a positive.
Adson's and Halstead tests for thoracic outlet syndrome can also provide useful diagnostic information in the diagnosis and treatment of brachial neuritis.