Management of Autonomic Dysfunction in Charcot-Marie-Tooth Disease Type 1B

Introduction to Autonomic Dysfunction

• The American Diabetes Association recommends evaluating patients with Charcot-Marie-Tooth disease type 1B (CMT1B) for autonomic dysfunction, which can include orthostatic hypotension, gastrointestinal issues, and other autonomic manifestations 1

Diagnostic Evaluation

• The American Heart Association suggests performing a thorough autonomic evaluation, including orthostatic vital signs, autonomic function testing, and screening for other causes of autonomic dysfunction that may coexist, in patients with CMT1B 1
• The American Diabetes Association recommends considering referral for specialized autonomic evaluation, particularly with progressive symptoms, in patients with CMT1B 1
• Autonomic function testing, including deep-breathing test and Valsalva maneuver, should be performed to assess heart rate variability, as recommended by the European Heart Journal 2
• Screening for underlying causes of autonomic dysfunction, including diabetes mellitus, adrenal insufficiency, thyroid dysfunction, vitamin deficiencies, autoimmune conditions, amyloidosis, and Parkinson's disease and other neurodegenerative disorders, is recommended by the European Society of Cardiology and American Autonomic Society 3, 4, 5
• Orthostatic vital signs should be measured by assessing blood pressure and heart rate in supine position and after standing for 1-3 minutes, according to the European Society of Cardiology 2
• Tilt table testing can be used to evaluate orthostatic intolerance and vasovagal responses, as recommended by the European Heart Journal 5
• 24-hour ambulatory blood pressure monitoring can be used to identify nocturnal "non-dipping" or "reverse-dipping" patterns characteristic of autonomic failure, as suggested by the European Society of Hypertension 2
• Antibody testing, including anti-ganglionic acetylcholine receptor antibodies, antineuronal nuclear antibody type 1, and N-type voltage-gated calcium channel antibodies, can be used to diagnose autonomic dysfunction, as recommended by the American College of Rheumatology 3

Management of Orthostatic Hypotension

• The American Autonomic Society recommends non-pharmacological measures, such as increased fluid intake and waist-high compression stockings, as first-line treatment for orthostatic hypotension in patients with CMT1B 1
• Increasing fluid intake to 2-3 liters daily and salt intake to 8-10g daily (unless contraindicated) can help manage dysautonomia, as recommended by the European Heart Journal 5
• Waist-high compression stockings (30-40 mmHg) and abdominal binders can be used to improve venous return, as recommended by the European Heart Journal 5
• Small, frequent meals can help avoid post-prandial hypotension, and limiting alcohol and caffeine intake is also recommended by the European Heart Journal 5
• Fludrocortisone (0.1-0.2 mg daily) can be used for volume expansion and increased sodium retention, and midodrine (2.5-10 mg TID) as an alpha-1 adrenergic agonist for peripheral vasoconstriction, as recommended by the European Heart Journal 5
• Pyridostigmine, an acetylcholinesterase inhibitor, can enhance sympathetic ganglionic transmission, as recommended by the European Heart Journal 5
• Discontinuing or reducing medications that exacerbate orthostatic hypotension, including antihypertensives, tricyclic antidepressants, alpha-blockers, and diuretics, is recommended by the American College of Cardiology 6

Management of Gastrointestinal Dysfunction

• The American Gastroenterological Association suggests that prokinetic agents may be considered for symptom management in patients with gastroparesis and CMT1B 7
• The American Gastroenterological Association recommends osmotic laxatives if needed, for patients with constipation and CMT1B 7

Management of Genitourinary Issues

• The American Urological Association recommends evaluation for patients with recurrent urinary tract infections, incontinence, or palpable bladder, and consideration of referral to urology for specialized assessment, in patients with bladder dysfunction and CMT1B 7

Management of Sexual Dysfunction

• The American Urological Association suggests appropriate treatment based on underlying mechanisms, for patients with sexual dysfunction and CMT1B 7

Management of Neuropathic Pain

• The American Diabetes Association recommends first-line medications, such as gabapentin, pregabalin, duloxetine, and tricyclic antidepressants, for neuropathic pain in patients with CMT1B 8
• The American Diabetes Association suggests careful attention to cardiovascular autonomic neuropathy, which is associated with increased mortality, in patients with CMT1B 7

Monitoring and Follow-up

• The American Heart Association recommends regular assessment of autonomic symptoms and response to interventions, monitoring for disease progression and development of new autonomic symptoms, and regular assessment of orthostatic vital signs to guide treatment adjustments, in patients with CMT1B 7
• Regular monitoring of orthostatic vital signs and symptom diaries can help track response to interventions, and treatment should be adjusted based on symptom severity and response 5
• Careful monitoring of nocturnal hypertension, which is common in autonomic failure, is recommended by the European Heart Journal 5
• Nocturnal hypertension, often characterized by "reverse dipping" patterns, requires careful blood pressure monitoring and management, as recommended by the European Society of Hypertension 2
• IVIG can be used to treat immune-mediated or paraneoplastic autonomic dysfunction, with a dose of 0.4 g/kg/day for 5 days, as suggested by the American Society for Clinical Oncology 9
• Prednisone 0.5-1 mg/kg can be considered for patients with moderate symptoms, and neurological consultation should be sought, as stated by the American Academy of Neurology 3, 4
• Methylprednisolone 1 g daily for 3 days followed by oral corticosteroid taper can be used to treat patients with severe symptoms, as recommended by the American College of Cardiology 3, 4
• Complete discontinuation of e-cigarettes and vaping products is the most critical intervention, according to Diabetes Care 10
• Avoidance of nicotine-containing products is recommended, as stated in the European Heart Journal 2