From the Guidelines
Diagnosing brachial neuritis requires a combination of clinical evaluation, patient history, and diagnostic tests, with electromyography (EMG) and nerve conduction studies being essential diagnostic tools, as supported by the most recent guidelines 1. To approach the diagnosis, it's crucial to start with a thorough history focusing on the characteristic sudden onset of severe shoulder and upper arm pain, typically followed by weakness and muscle wasting after the pain subsides.
- A physical examination should assess muscle strength, particularly in the shoulder, arm, and hand, looking for weakness in specific muscle groups supplied by the brachial plexus.
- Sensory testing may reveal areas of numbness or altered sensation. The use of EMG and nerve conduction studies is critical, as they typically show denervation in affected muscles and abnormal nerve conduction, which are key findings in brachial neuritis, as noted in the context of nontraumatic brachial plexopathy 1.
- MRI of the brachial plexus may help rule out other conditions and sometimes shows inflammation or edema of the affected nerves.
- Laboratory tests, including complete blood count, inflammatory markers, and autoimmune panels, can help exclude other causes, such as systemic, inflammatory, and/or immune-mediated processes that involve the brachial plexus, including Parsonage-Turner syndrome, chronic inflammatory neuropathies, and hereditary neuropathies 1. Diagnosis often requires excluding other conditions that mimic brachial neuritis, such as cervical radiculopathy, rotator cuff injuries, or other peripheral neuropathies.
- The combination of the characteristic clinical presentation (severe pain followed by weakness), supportive EMG findings, and exclusion of alternative diagnoses establishes the diagnosis of brachial neuritis, aligning with the recommendations for evaluating nontraumatic brachial plexopathy 1.
From the Research
Diagnosis of Brachial Neuritis
To diagnose brachial neuritis, the following methods can be used:
- Clinical history and examination: Diagnosis of brachial neuritis is usually based on clinical history and examination, with the confirmation by electrodiagnostic tests 2.
- Electrodiagnostic tests: Electromyographic findings of fibrillation potentials and positive waves characteristically are found in a pattern indicating combined nerve-root and peripheral nerve involvement 3.
- Electromyography (EMG): EMG more frequently than clinical examination shows that the lesion is bilateral, and also is of both diagnostic and prognostic value 3.
- Magnetic Resonance Imaging (MRI): MRI can show thickening and hyperintensity of the bilateral brachial plexus, which can be helpful in diagnosing brachial neuritis with pure sensory involvement 2.
- Laboratory tests: Laboratory tests, such as those to exclude other causes of shoulder pain, may also be used in the diagnosis of brachial neuritis 3, 4.
Characteristics of Brachial Neuritis
Brachial neuritis is characterized by:
- Sharp pain in the shoulder or elbow, which is usually short-lived 3, 5, 6.
- Weakness, which generally occurs as the pain is subsiding, and most frequently involves the deltoid, spinati, serratus anterior, biceps, and triceps muscles 3, 6.
- Paresthesias, atrophy, and sensory loss, which are inconstant features 3.
- A variable clinical course, but in 90 per cent of patients complete recovery occurs within three years 3.