Dysautonomia

The topic of this page is Dysautonomia/POTS, a condition we see occasionally at Shands. This is quite disabling and misunderstood, so I wanted to provide a brief overview.

What is Dysautonomia?

It’s an umbrella term for disorders of the Autonomic Nervous System (ANS).

• ANS regulates involuntary body functions (HR, BP, digestion, temperature, sweating) 
• In dysautonomia, ANS responds inappropriately to physiologic demands (standing, eating, stress, heat, exertion) 
• Includes:
  • POTS (postural orthostatic tachycardia syndrome) – by far, most common 
  • Vasovagal syncope 
  • Multiple system atrophy (neurodegenerative) 
  • Autoimmune autonomic ganglionopathy 
  • Secondary dysautonomia (small fiber neuropathy, DM, Parkinson’s, Ehler’s Danlos) 

What is POTS?

• Defined by:
  • Excessive HR increase on standing 
  • Without significant drop in BP 
• Diagnostic criterion:
  • HR increase >30 within 10 min of standing or tilt, without orthostatic hypotension 

How common is dysautonomia? POTS? 

• Dysautonomia: exact prevalence unknown, likely underdiagnosed 
• POTS: estimate 0.1-1% of population
  • 80-85% female 
  • Peak onset: adolescence to early adulthood 

What are are the symptoms of dysautonomia? 

• Cardiovascular
  • Tachycardia, palpitations, presyncope/syncope, chest discomfort, BP lability 
• Neurologic
  • Paresthesias, numbness, headache, brain fog, blurry vision 
• Fatigue, sleep disturbance 
• GI
  • Nausea, early satiety, bloating, abdominal pain, diarrhea 
• Thermoregulatory
  • Heat/cold intolerance, sweating changes, fever 
• Respiratory
  • SOB 
• MSK
  • Pain, weakness, blood poolign in legs/feet 
• GU
  • Urinary frequency, incomplete bladder emptying, sexual dysfunction 
• Psychiatric
  • Panic-like episodes, low mood, depersonalization/derealization, irritability 

Why can dysautonomia be confused with psychiatric conditions? 

• Symptoms overlap with anxiety and panic 
• Standard labs and imaging often normal 
• Symptoms worsen with stress 

How do you diagnose it? 

• Clinical history (most important) 
  • Orthostatic symptoms, triggers: standing, heat, meals, exertion, symptom relief when lying down 
• Objective
  • Orthostatic vitals 
• Supportive tests
  • Autonomic reflex testing 
    • Tilt-table testing: objective evidence of orthostatic intolerance 
    • Sudomotor testing: 50% of POTS shows abnormalities 
  • Labs (exclude other causes) 
    • CMP, CBC, thyroid function, EKG 
    • Targeted (based on sx)
      • Morning cortisol 
      • Echocardiography 
      • Supine/standing plasma catecholamines 
      • 24 hour urine sodium 
      • Gastric motility testing 
      • Serum tryptase (mast cell activation disorder) 

What is the treatment? 

• Non-pharm (first-line) 
  • Increase fluid/salt intake 
  • Compression garments 
  • Physical reconditioning 
  • Avoid heat/prolonged standing 
  • Small, frequent meals 
• Medications (selected patients)
  • Beta blockers, Ivabradine, fludrocortisone, midodrine, pyridostigmine, SSRI/SNRI (for autonomic modulation, not just anxiety) 
• Psychiatric support
  • Education/validation, CBT on coping, not sx dismissal 
  • Treat comorbid depression/anxiety