The role of the cardiologist in the evaluation of dysautonomia

Abstract

Dysfunction of the autonomic nervous system, or dysautonomia, is an uncommon disease. Postural orthostatic tachycardia syndrome is one of the several types of dysautonomia. Postural orthostatic tachycardia syndrome, also known as chronic orthostatic intolerance, is the most common but least severe of the dysautonomic disorders; it will serve as the model for evaluation and management of the other dysautonomias. Overall, these patients can have variable dysfunction of the autonomic nervous system that is more severe than that observed in typical neurocardiogenic syncope. Frequently, providers are not familiar with either the evaluation or the management of this syndrome, or are just not interested in doing so. This article attempts to describe strategies for evaluation and management of postural orthostatic tachycardia syndrome. The diagnosis of postural orthostatic tachycardia syndrome is made by the finding of orthostatic intolerance associated with a pulse greater than 120 beats per minute in the first 10 minutes of upright position or an elevation in pulse greater than 30 beats per minute in the first 10 minutes of upright position. Overall, these patients can have variable dysfunction of the autonomic nervous system that is more severe than that seen in typical neurocardiogenic syncope. A wide variety of associated symptoms may exist and these symptoms can have tremendous impact on the lives of the patients and their families. Management of these patients can be difficult as well as rewarding. It is helpful to perform an extensive education up front with these patients and their families. Interventions for patients with postural orthostatic tachycardia syndrome typically fall into two broad categories: non-pharmacological and pharmacological. Non-pharmacological therapies are varied, but are based primarily on ensuring adequate status of intravascular fluid. Polypharmacy may be required to control symptoms associated with postural orthostatic tachycardia syndrome. On account of the severity of their symptoms, these patients frequently have difficulty in completing their school assignments. The physician may need to help support the attempts of the family to work with the school to help the patient stay in school. As postural orthostatic tachycardia syndrome is underdiagnosed and poorly understood, it is a disease that provides an excellent opportunity to perform research. The most important studies would be those that aim to elucidate an aetiology and a pathophysiology of postural orthostatic tachycardia syndrome. In the final analysis, the role of the cardiologist in the evaluation and management of a patient with dysautonomia is to help a patient with severe disability to feel as if they are normal, or much closer to it.