Autonomic Nervous System Disorders

The nervous system is generally broken into two major areas: the central nervous system and the peripheral nervous system. The autonomic nervous system (a subdivision of the peripheral nervous system) is responsible for the internal organs. It handles involuntary actions, such as the heartbeat, breathing and digestion. This system is comprised of the sympathetic nervous system, which engages the stress response, and the parasympathetic nervous system, which handles relaxing the body after stress. The autonomic nervous system can be affected by numerous conditions.

Autonomic Neuropathy

• Autonomic neuropathy is a condition in which the autonomic nerves have been damaged. The damage to these nerves interrupts the signal transmission between the nerves and the brain. This can affect the proper function of the heart, the dilation of blood vessels, breathing, and contribute to erectile dysfunction. Autonomic neuropathy does not have a single cause. It can develop due to autoimmune diseases that cause the body to attack itself, medications, diabetes, Parkinson's disease and amyloidosis (an abnormal protein buildup).

Multiple System Atrophy With Orthostatic Hypotension

• Multiple system atrophy with orthostatic hypotension, or Shy-Drager syndrome, is a progressive condition that affects both the central and autonomic nervous systems. It is characterized by a sudden and extreme drop in blood pressure that occurs when a person stands up and can lead to fainting. There are three types of the condition: Parkinsonian, cerebellar and combined. Parkinsonian is characterized by tremors and slow movement. Cereballar is characterized by problems with speech and coordination. Combined manifests with symptoms from both types.

Holmes-Adie Syndrome

• Holmes-Adie syndrome is a condition that affects the autonomic nervous system, the pupils and deep tendon reflexes. The major symptoms of the condition are one or both pupils constricting slowly when exposed to bright light and poor or absent deep tendon reflexes (particularly the Achilles tendon). It is believed to be caused by viral or bacterial damage to the ciliary and spinal ganglions, which respectively handle eye movement and autonomic nervous system responses.

Postural Tachycardia Syndrome

• Postural orthostatic tachycardia syndrome is a condition that is principally defined by the presence of orthostatic intolerance. Orthostatic intolerance occurs when an insufficient blood volume reaches the heart when a person stands up after lying down. Symptoms of the condition include dizziness, fainting and dramatic increase in the heart rate. It is believed to be the result of abnormalities or damage to the autonomic nervous system, specifically to the sympathetic nervous system, parasympathetic nervous system or possibly to both.

Vasovagal Syncope

• Vasovagal syncope, more commonly referred to as fainting, is a condition brought about by an inappropriate response in the autonomic nervous system. It is typically triggered by intense emotion or a troubling visual stimulus, such as blood. Rather than engaging the stress response, which increases heart rate, blood pressure and adrenaline production, the autonomic nervous system allow the heart rate to slow while dilating blood vessels in the legs. This allows blood to accumulate in the legs and deprives blood to the brain. This results in a short loss of consciousness.