What is the primary management approach for autonomic dysfunction associated with brachial plexopathy?

Management of Autonomic Dysfunction in Brachial Plexopathy

The primary management approach for autonomic dysfunction associated with brachial plexopathy should focus on identifying the underlying etiology while providing symptomatic treatment based on severity, with neurological consultation recommended for comprehensive evaluation and targeted therapy. 1, 2

Diagnostic Evaluation

• MRI of the brachial plexus is the gold standard for evaluation of brachial plexopathy, requiring specialized protocols with orthogonal views through the oblique planes of the plexus, T1-weighted, T2-weighted, fat-saturated T2-weighted sequences, and short tau inversion recovery (STIR) sequences 1, 2
• Comprehensive screening for other causes of autonomic dysfunction should include:
  • Diabetic screen, adrenal insufficiency testing, HIV, paraproteinemia, amyloidosis, and botulism evaluation 1
  • Consideration of chronic diseases such as Parkinson's and other autoimmune conditions 1
  • Orthostatic vital signs measurement 1, 3
• Electrodiagnostic studies (NCS and EMG) should be performed to evaluate for concurrent polyneuropathy and confirm the diagnosis of plexopathy 1, 4
• Consider paraneoplastic autoimmune dysautonomia antibody testing (e.g., antiganglionic AChR, ANNA-1, and N-type voltage-gated calcium channel antibodies) 1

Management Based on Severity

Mild Autonomic Dysfunction (no interference with function)

• Monitor symptoms closely for progression 1
• If related to immune checkpoint inhibitor therapy, consider holding the medication with close monitoring 1

Moderate Autonomic Dysfunction (some interference with ADLs)

• Neurological consultation is recommended 1
• Consider initiating prednisone 0.5-1 mg/kg/day if symptoms are progressing from mild or if inflammatory etiology is suspected 1
• For neuropathic pain, consider gabapentin, pregabalin, or duloxetine 1
• If related to immune checkpoint inhibitor therapy, hold treatment until symptoms improve to mild grade 1

Severe Autonomic Dysfunction (limiting self-care)

• Immediate neurological consultation is essential 1
• Consider hospital admission for close monitoring 1
• Initiate methylprednisolone 1g daily for 3 days followed by oral steroid taper if inflammatory etiology is suspected 1
• Monitor for cardiovascular and respiratory complications, as these can be life-threatening 1
• If related to immune checkpoint inhibitor therapy, permanently discontinue treatment 1

Management of Specific Autonomic Symptoms

• Orthostatic hypotension:
  • Gradual position changes, compression stockings, increased salt and fluid intake 3
  • Consider fludrocortisone or midodrine in severe cases 3
• Cardiovascular autonomic dysfunction:
  • Regular monitoring of heart rate and blood pressure 1
  • Consider ECG monitoring for arrhythmias 1
• Gastrointestinal dysfunction:
  • For gastroparesis: small, frequent meals; prokinetic agents 3
  • For constipation: increased fiber intake, adequate hydration, and laxatives as needed 3
• Genitourinary dysfunction:
  • For bladder dysfunction: timed voiding, intermittent catheterization if necessary 3
  • For erectile dysfunction: comprehensive evaluation including vascular and neurological assessment 3
• Sudomotor dysfunction:
  • Skin care to prevent fissures and ulcers 3
  • Maintain hydration and avoid extreme temperatures 3

Considerations Based on Etiology

• Traumatic brachial plexopathy with autonomic symptoms:
  • Early surgical exploration may be necessary for penetrating and open injuries 2, 5
  • Conservative management for closed injuries based on severity 2
• Inflammatory/immune-mediated plexopathy (e.g., Parsonage-Turner syndrome):
  • Physical therapy to maintain range of motion 2
  • Anti-inflammatory medications 2, 6
• Neoplastic plexopathy:
  • Treatment directed at underlying malignancy 6
  • Consider FDG-PET/CT for evaluation 2
• Radiation-induced plexopathy:
  • Symptomatic management as radiation damage is often permanent 6

Common Pitfalls and Caveats

• Autonomic dysfunction in brachial plexopathy can be easily overlooked, leading to delayed diagnosis and treatment 5, 7
• Routine neck, chest, or spine MRI protocols are inadequate for proper evaluation of the brachial plexus; specialized protocols are required 1, 2
• Pain management is critical as neuropathic pain can significantly impact quality of life 7
• Autonomic symptoms may precede other complications, making early recognition important 1
• Mixed central and peripheral mechanisms may contribute to symptoms, particularly in traumatic avulsion injuries, potentially making treatment more challenging 7