Yesterday's Neurasthenia, Today's DysautonomiaPeople who a century ago would have been called neurasthenics today are given a host of diagnoses. These include chronic fatigue syndrome (CFS), vasovagal or neurocardiogenic syncope, panic attacks, anxiety, inappropriate sinus tachycardia (IST), irritable bowel syndrome (IBS), postural orthostatic tachycardia syndrome (POTS), or fibromyalgia. Sufferers of all these conditions tend to experience an imbalance, and most often a peculiar volatility, in the autonomic nervous system. We now call this dysautonomia.
The Autonomic Nervous System And DysautonomiaThe autonomic nervous system controls the “unconscious” bodily functions, such as heart rate, digestion, and breathing patterns. It consists of two parts: the sympathetic system and the parasympathetic system. The sympathetic system can best be thought of as controlling the “fight or flight” reactions of the body, producing the rapid heart rates, increased breathing, and increased blood flow to the muscles that are to escape danger or cope with stress. The parasympathetic system controls the “quiet” body functions, such as the digestive system. So: the sympathetic system gets us ready for action, while the parasympathetic system gets us ready for rest. Normally, the parasympathetic and sympathetic components of the autonomic nervous systems are in perfect balance, from moment to moment, depending on the body’s instantaneous needs. In people suffering from dysautonomia, the autonomic nervous system loses that balance, and at various times the parasympathetic or sympathetic systems inappropriately predominate. Symptoms can include frequent vague but disturbing aches and pains, faintness (or even actual fainting spells), fatigue and inertia, severe anxiety attacks, tachycardia, hypotension, poor exercise tolerance, gastrointestinal symptoms such as irritable bowel syndrome, sweating, dizziness, blurred vision, numbness and tingling, and -- quite understandably -- anxiety and depression.
Sufferers of dysautonomia can experience all these symptoms or just a few of them. They can experience one cluster of symptoms at one time, and another set of symptoms at other times. The symptoms are often fleeting and unpredictable, but on the other hand they can be triggered by specific situations or actions. (Some people have symptoms with exertion, for instance, or when standing up, or after ingesting certain foods.) And since people with dysautonomia are usually normal in every other way, when the doctor does a physical exam he or she often finds no abnormalities.