David S. Younger - The Autoimmune Brain: A Five-Step Plan for Treating Chronic Pain, Depression, Anxiety, Fatigue, and Attention Disorders

A neurologist focuses on three core areas of health:

• The central nervous system (CNS): the brain and the spinal cord
• The peripheral nervous system (PNS): the network of nerves leaving the brain and spinal cord, continuing to the muscles and the skin
• The autonomic nervous system (ANS): how the brain and body regulate functions beyond our conscious control, such as temperature, digestion and metabolism, breathing, and heartbeat.

Everything we do, all day long (and at night as well) involves these three systems either independently or in an overlapping fashion. It takes a very careful coordination of these three basic systems in order to maintain focus, balance, and high cognitive function. Picture in your mind the classic image of a Native American riding a horse, with bow and arrow drawn, tracking his prey across the desert plains. When our bodies are used at their fullest potential, we are coordinating intellect, balance, and muscular coordination.

You can categorize your physical symptoms into one of these three systems. The ANS has three branches: the sympathetic nervous system, the parasym-pathetic nervous system, and the enteric nervous system. The sympathetic nervous system controls hormonal output and the fight or flight response, whereas the parasympathetic nervous system monitors our ability to rest and digest. The ANS, also known as the visceral organ nervous system, is connected with motor functions, causing muscles to contract or relax; and balances circulatory function throughout the body, including the brain, through its control of blood vessels, which is referred to as vascular tone. ANS disorders can disturb normal bladder, bowel, and sexual function and lead to deficient vital signs with postural changes. Other common manifestations include temperature dysregulation, skin color changes, hair loss, increased or decreased perspiration, and as youll see later in this chapter, postural ortho-static tachycardia syndrome (POTS) and orthostatic hypotension. The third branch of the ANS, the enteric nervous system, operates autonomously yet communicates with the CNS by using brain chemicals called neurotransmitters, most of which are identical to the ones found in the CNS.

CNS disorders are typically uncommon and degenerative, and have very specific features that will facilitate a correct diagnosis. Amyotrophic lateral sclerosis, better known as Lou Gehrig disease, is a CNS disease that unmistakably involves the brain and spinal cord. It is suggested by the symptom cluster of progressive pharyngeal and limb weakness, wasting and twitching, and spasticity that results from degenerative loss of upper and lower motor neurons of the brain and spinal cord.

PNS disorders also have typical features. Guillain-Barre syndrome, abbreviated GBS, causes unmistakable ascending weakness and sensory loss over days resulting in progressive paralysis. More common expressions of PNS disturbance are the numbing and tingling sensations of neuropathy that occur with diabetes or Lyme disease.

Neurological symptoms may be unmistakable for a given disorder; in other circumstances, they may not be so straightforward. For instance, each of these three systems can be affected by, or create, symptoms like fatigue, forgetfulness, cognitive changes, panic attacks, and anxiety. Panic attacks can be thought of as an outflow of the ANS, a sort of unrestrained hyperactive dynamic state that cannot be controlled.

BOX 1.1

THE BRAINSKIN CONNECTION

The skin is your largest organ and has both peripheral and autonomic components. The skin has pain and temperature receptors, which belong to the peripheral nervous system and are catalogued as small fibers because they can only be seen with a microscope. A second type, small nerve fibers are classified as part of the autonomic nervous and sensory systems. The small autonomic fibers are effectors in nature, originating in the brains hypothalamus, descending through the brain stem, spinal cord, and along spinal roots to insert themselves into peripheral nerves of the limbs and trunk where they gain access to skin organs such as sweat glands, blood vessels, and hair follicles. By contrast, small sensory fibers in the skin are receptive in nature, provide pain and temperature receptors that transmit information to the brain in the opposite direction by connecting with the peripheral nerves and spinal roots, up through the spinal cord and brain stem on their way to the brain for conscious appreciation of these senses.