Brachial Neuritis

Overview

Brachial neuritis is an inflammatory condition affecting the brachial plexus, a complex network of nerves that originates from the spinal cord in the neck and extends to the shoulder, arm, and hand. This condition is characterized by a distinctive two-phase pattern: an initial acute phase of excruciating shoulder pain, followed by a subacute phase marked by progressive muscle weakness and atrophy.

The condition affects approximately 1.64 per 100,000 people annually, with men being affected twice as often as women. The peak incidence occurs in the third and fourth decades of life, though it can affect individuals of any age. The term "Parsonage-Turner syndrome" honors the neurologists who first described the condition in detail in 1948, though similar cases were documented as early as the 1800s.

Brachial neuritis can be classified into two main types: idiopathic (unknown cause) accounting for about 96% of cases, and hereditary (familial) accounting for the remaining 4%. The idiopathic form typically affects one side of the body, while the hereditary form may be bilateral and recurrent. Recovery is generally good but can be prolonged, with most patients experiencing significant improvement over 6 months to 2 years.

Symptoms

Brachial neuritis presents with a characteristic progression of symptoms that typically evolves through distinct phases. The condition usually begins suddenly and follows a predictable pattern of pain followed by weakness.

Acute Phase (Hours to Days)

• Shoulder pain - severe, sudden onset, often described as burning or crushing
• Pain that is constant and throbbing, worse at night
• Pain may radiate to the neck, arm, or hand
• Pain typically affects one side but can be bilateral
• Inability to find comfortable position for sleep
• Pain may be so severe it prevents normal activities

Subacute Phase (Days to Weeks)

• Gradual reduction in pain intensity
• Progressive muscle weakness in affected arm
• Difficulty lifting the arm or shoulder
• Weakness in specific muscle groups depending on nerve involvement
• Numbness or tingling in fingers or hand
• Reduced reflexes in affected arm

Chronic Phase (Weeks to Months)

• Muscle atrophy (wasting) becomes visible
• Persistent weakness despite pain resolution
• Altered sensation in affected areas
• Functional limitations in daily activities
• Possible permanent weakness in severely affected muscles
• Compensatory movement patterns

Common Muscle Groups Affected

• Serratus anterior: Difficulty raising arm overhead, winging of shoulder blade
• Deltoid: Weakness in lifting arm to the side
• Biceps: Difficulty bending elbow
• Supraspinatus: Trouble initiating arm abduction
• Infraspinatus: Weakness in external rotation of arm
• Diaphragm: Rare but possible breathing difficulties

Causes

The exact cause of brachial neuritis remains unclear in most cases, but it is believed to result from an abnormal immune response that leads to inflammation of the brachial plexus nerves. This autoimmune reaction can be triggered by various factors.

Infectious Triggers

• Viral infections: Epstein-Barr virus, cytomegalovirus, hepatitis E, HIV
• Bacterial infections: Staphylococcus, streptococcus, mycoplasma
• Upper respiratory infections: Common cold, flu
• Parasitic infections: Toxoplasma, trichinella

Immunological Triggers

• Vaccinations: Tetanus, diphtheria, influenza, hepatitis B, COVID-19
• Autoimmune conditions: Systemic lupus erythematosus, polyarteritis nodosa
• Allergic reactions: Drug allergies, environmental allergens
• Immune system stress: Pregnancy, surgery, severe illness

Physical and Surgical Triggers

• Surgical procedures: Particularly cardiac, thoracic, or orthopedic surgery
• Anesthesia: General or regional anesthesia complications
• Trauma: Though less common than other causes
• Medical procedures: Lymph node biopsy, arterial catheterization

Hereditary Form

• Autosomal dominant inheritance pattern
• Mutations in SEPT9 gene
• Recurrent episodes affecting multiple family members
• May be triggered by minor stresses like exercise or childbirth

Risk Factors

While brachial neuritis can affect anyone, certain factors may increase the likelihood of developing this condition.

Demographic Factors

• Age: Most common in 20-60 years old, peak in 30s-40s
• Gender: Men affected 2-3 times more often than women
• Family history: Increased risk with hereditary form

Medical History

• Recent infection (within 4 weeks)
• Recent vaccination (within 4 weeks)
• Recent surgery or hospitalization
• Autoimmune disorders
• Previous episodes of brachial neuritis
• Pregnancy or recent childbirth

Lifestyle and Environmental Factors

• High stress levels
• Intense physical activity or exercise
• Exposure to certain medications or toxins
• Occupational exposure to certain chemicals

Diagnosis

Diagnosing brachial neuritis is primarily based on clinical presentation and characteristic symptoms, as there is no single definitive test. The diagnosis relies on recognizing the typical pattern of severe shoulder pain followed by weakness.

Clinical Assessment

Medical History

• Detailed symptom timeline and progression
• Recent infections, vaccinations, or surgeries
• Family history of similar episodes
• Previous episodes of arm weakness or pain

Physical Examination

• Neurological assessment of affected arm
• Muscle strength testing
• Sensation testing for numbness or altered feeling
• Reflex testing
• Assessment for muscle atrophy
• Evaluation of shoulder blade movement

Diagnostic Tests

Electromyography (EMG) and Nerve Conduction Studies

• Most important diagnostic tools
• Can identify specific nerve involvement
• Best performed 3-4 weeks after symptom onset
• Shows denervation changes in affected muscles
• Helps differentiate from other nerve conditions

Magnetic Resonance Imaging (MRI)

• Can show muscle changes and nerve inflammation
• Helps rule out structural abnormalities
• May show increased signal in affected muscles
• Useful for excluding other conditions

Laboratory Tests

• Blood tests to rule out systemic infections
• Inflammatory markers (ESR, CRP)
• Autoimmune panel if indicated
• Vitamin levels (particularly B vitamins)

Differential Diagnosis

• Cervical radiculopathy
• Rotator cuff tear
• Thoracic outlet syndrome
• Peripheral nerve tumors
• Inflammatory myopathy
• Multiple sclerosis

Treatment Options

Treatment for brachial neuritis focuses on pain management during the acute phase and rehabilitation to restore function during the recovery phase. While there is no specific cure, most patients experience significant recovery with appropriate management.

Acute Phase Treatment (Pain Management)

Medications

• Corticosteroids: Prednisone may reduce inflammation and shorten pain duration
• Strong analgesics: Opioids may be needed for severe pain
• Neuropathic pain medications: Gabapentin, pregabalin
• Anti-inflammatory drugs: NSAIDs for mild to moderate pain
• Muscle relaxants: For associated muscle spasm

Non-pharmacological Pain Management

• Ice application during acute phase
• Gentle positioning and support for affected arm
• Sleep modifications and pillow support
• Transcutaneous electrical nerve stimulation (TENS)
• Relaxation techniques and stress management

Recovery Phase Treatment

Physical Therapy

• Range of motion exercises: Prevent joint stiffness
• Strengthening exercises: Restore muscle function
• Functional training: Improve daily activity performance
• Compensatory strategies: Work around permanent deficits
• Electrical stimulation: May help prevent muscle atrophy

Occupational Therapy

• Adaptive techniques for daily activities
• Workplace modifications and ergonomics
• Assistive devices and equipment
• Energy conservation strategies

Advanced Treatment Options

• Nerve transfer surgery: For cases with poor recovery
• Tendon transfers: To restore lost function
• Orthotic devices: Braces to support weak muscles
• Injection therapy: Nerve blocks for persistent pain

Treatment Timeline

• 0-4 weeks: Focus on pain control and gentle range of motion
• 1-3 months: Begin strengthening as pain allows
• 3-6 months: Intensive rehabilitation program
• 6+ months: Adaptive strategies for persistent deficits

Prevention

Since brachial neuritis often occurs unpredictably and the exact trigger is frequently unknown, prevention can be challenging. However, certain strategies may help reduce the risk of developing the condition or experiencing recurrent episodes.

General Prevention Strategies

• Maintain good overall health: Regular exercise, balanced diet, adequate sleep
• Stress management: Practice stress-reduction techniques
• Prompt treatment of infections: Seek medical care for significant infections
• Vaccination awareness: Discuss timing with healthcare provider if multiple vaccines needed
• Workplace ergonomics: Proper posture and work station setup

For Those with Previous Episodes

• Genetic counseling for hereditary form
• Early recognition of symptoms
• Prompt medical attention for recurrent pain
• Maintain shoulder and arm flexibility
• Regular follow-up with healthcare providers

Surgical Prevention

• Careful patient positioning during surgery
• Avoid excessive stretching of arms during procedures
• Proper anesthetic technique
• Post-operative monitoring for nerve symptoms

When to See a Doctor

Seek immediate medical attention for:

• Sudden, severe shoulder pain that prevents normal activities
• Shoulder pain accompanied by fever or signs of infection
• Progressive weakness in arm or hand
• Numbness or tingling that worsens over time
• Inability to move arm or shoulder normally
• Breathing difficulties (rare but possible with diaphragm involvement)

Schedule an appointment for:

• Persistent shoulder pain lasting more than a few days
• Gradual onset of arm weakness
• History of similar episodes
• Family history of recurrent arm weakness or pain
• Concern about symptoms following vaccination or infection

Follow-up care needed for:

• Monitoring recovery progress
• Adjusting pain management strategies
• Physical therapy referrals
• Assessment for complications or poor recovery

Related Conditions

• Cervical Radiculopathy
• Thoracic Outlet Syndrome
• Rotator Cuff Injury
• Peripheral Neuropathy
• Carpal Tunnel Syndrome
• Frozen Shoulder

References

1. van Alfen N, van Engelen BG. The clinical spectrum of neuralgic amyotrophy in 246 cases. Brain. 2006;129(Pt 2):438-450.
2. Feinberg JH, Radecki J. Parsonage-turner syndrome. HSS J. 2010;6(2):199-205.
3. Buccolieri G, Torrieri F, Cianci V, et al. Brachial plexus neuritis: clinical features, outcome and treatment. A systematic review of the literature. Eur Rev Med Pharmacol Sci. 2020;24(12):6748-6759.
4. Rubin DI. Neuralgic amyotrophy: clinical features and diagnostic evaluation. Neurologist. 2001;7(6):350-356.
5. Tsairis P, Dyck PJ, Mulder DW. Natural history of brachial plexus neuropathy. Report on 99 patients. Arch Neurol. 1972;27(2):109-117.