Autonomic nerve function in adults with cyclic vomiting syndrome: a prospective study.

Area of Science:

• Gastroenterology
• Neurology
• Autonomic Function Testing

Background:

• Cyclic vomiting syndrome (CVS) is a functional gastrointestinal disorder marked by recurrent vomiting episodes.
• Autonomic dysfunction is a potential, yet understudied, factor in CVS pathogenesis.
• This study prospectively investigates autonomic nerve function in CVS patients.

Purpose of the Study:

• To assess sympathetic and parasympathetic nervous system function in individuals diagnosed with CVS.
• To identify potential links between autonomic dysfunction and the pathophysiology of cyclic vomiting syndrome.
• To explore diagnostic and therapeutic implications of autonomic function in CVS.

Main Methods:

• Sympathetic nervous system function was evaluated using postural heart rate and blood pressure changes, alongside thermoregulatory sweat testing.
• Parasympathetic nervous system function was assessed via heart rate response to deep breathing (R-R variability).
• 20 CVS patients meeting Rome III criteria and 20 healthy controls were included.

Main Results:

• 85% of CVS patients exhibited abnormal thermoregulatory sweat test results, compared to 10% of controls (P < 0.001).
• 35% of CVS patients showed evidence of postural tachycardia, versus 5% of controls (P = 0.04).
• 90% of CVS subjects displayed either sudomotor dysfunction or postural tachycardia, or both, while parasympathetic function remained normal in most patients.

Conclusions:

• The majority of cyclic vomiting syndrome patients demonstrate sympathetic nervous system impairment, characterized by sudomotor dysfunction and/or postural tachycardia.
• Parasympathetic nerve function appears to be preserved in individuals with CVS.
• These findings highlight the significant role of dysautonomia in CVS and suggest avenues for improved diagnosis and treatment.