Autonomic Dysfunction
Dysfunction of the autonomic nervous system (ANS) is known as dysautonomia. Dysautonomia can be local, as in reflex sympathetic dystrophy, or generalized, as in pure autonomic failure. It can be acute and reversible, as in Guillain-Barre syndrome, or chronic and progressive. Several common conditions such as diabetes and alcoholism can include dysautonomia. Dysautonomia also can occur as a primary condition or in association with degenerative neurological diseases such as Parkinson's disease. Other diseases with generalized, primary dysautonomia include multiple system atrophy and familial dysautonomia. Hallmarks of generalized dysautonomia due to sympathetic failure are impotence (in men) and a fall in blood pressure during standing (orthostatic hypotension). Excessive sympathetic activity can present as hypertension or a rapid pulse rate1.
The autonomic nervous system regulates automatic body functions, including heart rate, blood pressure, temperature regulation, gastrointestinal secretion, and metabolic and endocrine responses to stress. The ANS influences multiple organ systems, and is composed of the sympathetic and parasympathetic nervous systems. ANS function in combat veterans has been extensively studied in the form of Heart Rate Variability analysis. The ANS regulates the activities of cardiac muscle, smooth muscle, endocrine glands, and exocrine glands. The autonomic nervous system functions in an automatic manner without conscious control. The ANS can act to excite or inhibit innervated tissue. The systems can act to stimulate organs and tissues in opposite ways (antagonistic). For example, parasympathetic stimulation acts to decrease heart rate. In contrast, sympathetic stimulation results in increased heart rate. The systems can also act in concert to stimulate activity. The ANS is responsible for the "fight or flight" mechanism that governs the human body's response to stress.
Dysautonomia has been detected in patients suffering from PTSD, Traumatic Brain Injury (TBI), and Gulf War Illness2-4. The impact of a stressful event, exposure to neurotoxic chemicals or severe brain damage impacts the function of both the sympathetic and parasympathetic nervous systems. This imbalance of ANS function can lead to increased amino acid turnover of choline, glutamine, tryptophan and tyrosine yielding a nutritional deficiency that in many cases cannot be addressed by altering diet alone. Rx only medical foods are a viable and sustainable option for physicians to utilize in clinical practice to provide patients with the neurotransmitter precursors required for restoring impaired parasympathetic activity.
- National Institute of Neurological Disorders and Stroke
- Choen, et al, Autonomic dysregulation in panic disorder and PTSD. Psychiatry Research 2000
- King, et al., Heart-rate variability in chronic traumatic brain injury. Brain Injury, 1997 vol 11
- Hayley , et al., Blunted circadian variation in autonomic regulation of sinus node function in veterans with gulf war syndrome. AJM 2004
