Biology 202
2002 Third Paper
On Serendip

Upon concluding my neurobiology course, I spent some time reflecting on what I've learned about the nervous system and its functions. I thought about how much progress has been made in the last couple of decades alone in defining and understanding certain aspects of neuronal functions, and must admit that I am very impressed. However, there is still so much we don't know about this area, and nowhere has this notion proved more true than in my exploration of Chronic Fatigue Syndrome. As will soon be clear, this disease is highly debilitating and can greatly lower the quality of an individual's life, yet to date there are no definite findings about the etiology of this illness. But even more importantly, this illness shows the importance of understanding and being able to assess the different workings of our nervous system and its complex nature. Unfortunately, the study of this same disease also shows the human inability to yet do so.

So what is Chronic Fatigue Syndrome, or CFS? I would like to be able to explain exactly what CFS is, but true to the nature of what is known about this illness, there is no precise way to describe CFS. Rather, the disease is identified through a number of symptoms (both physical and psychological), including unexplained and persistent fatigue of new or definite onset, concurrent with short-term memory loss, sore throat, tender axillary lymph nodes, muscle pain and unrefreshing sleep, among a number of others, for a duration of at least six months. As is probably evident, the above symptoms, in addition to being signs of CFS, are also the same (or very similar) symptoms experienced in such diseases as Lymes disease and "the flu." There are symptoms that involve the Gastrointestinal Tract (GI), immunological-related symptoms, symptoms of psychiatric disease like depression, sexual malfunction, endocrine dysfunction-basically every system in the body. This is part of the reason why CFS is hard to detect, and is usually chosen as a diagnosis only at the exclusion of all other possible ailments. The other difficulty that lies with diagnosing CFS is that there is no way of measuring the level of a person's fatigue-there is no way for a physician to tell whether a patient complaining of fatigue is experiencing the type of fatigue associated with CFS or he/she is just extremely tired and overworked. Nevertheless, diagnosed or not, it is estimated that about 800,000 Americans suffer from this disorder, whose etiology has yet to be defined (1), (3).

So what? Well, aside from that fact that I like learning and reading about "mystery" illnesses, the reason for my interest in this topic is imbedded in CFS's presumed connection to the nervous system, namely the brain. Many studies have found that patients with CFS, in comparison with healthy control subjects, have a variety of abnormalities of the hypothalamic-pituitary axes. For example, there is reduced hypothalamic production of corticotrophin releasing hormone, leading to diminished pituitary release of ACTH, leading to hypocortisolism. Also, it has been found that the adrenal glands of CFS patients are half the size of adrenals from healthy control subjects. In a study detecting regional cerebral blood flow in CFS, it was found that a deficit in the regional cerebral blood flow in the medial temporal lobe was definite in seven out of the thirteen CFS patients, including the brainstem, left medial temporal lobe, and right medial temporal lobe. Therefore, hypotension-an abnormality in the way the body regulates blood pressure, is a close link to CFS. This condition occurs when the central nervous system's autonomic portion (one controlling heart rate and blood pressure) misinterprets the body's needs during periods of upright posture and sends a message to the heart to slow down and lower blood pressure, which is the opposite of what the body needs at such times (3), (4).

Of course, testing a number of patients through certain methods and then interpreting the information in the context of what that specific test is looking for is quite easy. But what do all these test results mean in the context of CFS-in terms of finding a defining feature that sets CFS apart from all other diseases? The answer here is that no one is quite sure what all of this means. Not all CFS patients exhibit the same symptoms, and not all tests are one hundred percent reliable. However, one this is for certain. The makeup and function of our nervous system is very complex, and not easily studied. Even more importantly, the problem becomes even greater when one realizes that the nervous system is involved in and integral to all other systems of our body. So how do we set everything apart? How do we decide which particular system, or part of a system is malfunctioning? Is there a problem with a particular system, or is the input from several other systems incorrect? In the case of CFS, many systems are malfunctioning-the GI tract, blood pressure control systems, temperature control systems, and weight control systems, and for that reason this disease has been hard to diagnose and define (1), (2), (4).

During my studies of neurobiology, it has been my experience that the best way to understand the entire nervous system is to break it down into the simplest of concepts and work toward understanding the entire system (or perhaps I should say systems) and the way they intertwine, work together and are integral to one another's functioning, while contributing to an enormous amount of complexity. This method has served me well in allowing me to grasp a large amount of information and put it into some kind of order so that it makes sense. However, this approach has its shortcomings. As my exploration and understanding of Chronic Fatigue Syndrome suggests, it is often very difficult, and sometimes impossible, to divide the nervous system into parts, assigning each one a specific function. Rather, often times the systems that we are taught "make up" the nervous system are often indistinguishable from the nervous system itself.

Chronic Fatigue Syndrome is still mostly uncharted territory for most of today's scientists. It is a disease for which there are no definite causes, only a list of definite (although even that is not completely "definite") symptoms. But even though the exploration of this illness proves to be pretty new to many, the study of the nervous system is not. As I see it, this illness, although complex and unexplainable, is giving today's scientists and researchers the chance for further exploration and discovery of our already incredibly evolved, evolving, and extremely complex nervous system.

References

WWW. Sources:
1)WICFS Home Page, a good site on all perspectives of CFS

2)Wisconsin Institute for CFS, great resource of CFS

3)The Scientist –Genetic and Molecular Mysteries of Sleep are Keeping Researchers Alert, information on sleep disorders in general

4)Harvard Health Publications, News on latest CFS news from Harvard


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