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What’s Inside Fatigue and illness Liver problems Peripheral fatigue Research Views Responding to the reader Adolescent nutrition and lifestyle Basic research: the foundation for medicine Learning to walk...again At the Forefront Researchers in the making Heritage Youth Researcher Summer (HYRS) Program 2006 Reader Resources Fatigue and illness Why do we feel tired when we’re ill? In many illnesses—such as cancer, multiple sclerosis, rheumatoid arthritis, and liver disease—as well as infections, fatigue can be a major issue. Brain function drives the fatigue in these diseases, even though all of them occur outside of the brain, AHFMR Senior Scholar and Calgary hepatologist Dr. Mark Swain points out. “When we become sick with the flu or a bacterial infection, we feel tired, as well as losing our appetite and so on,” explains Dr. Swain. “The body signals the brain to produce these symptoms or behaviours. It’s important for us to conserve energy and not move around and do things—so we’ll get over the illness and get back to normal. Unfortunately, with a chronic disease, we don’t get over the illness. The stimuli to the brain keep happening. Our bodies try to adapt but they never fully do so.” Throughout his career as a physician and researcher, Dr. Swain has attempted to improve the quality of life and health outcomes for people suffering from liver disorders. More than 100 known forms of liver disease affect everyone from infants to older adults. Liver damage can result from viruses, cancer, autoimmune disorders, alcohol, drug use, toxins, and obesity. Liver problems Dr. Swain studies, diagnoses, and treats such liver problems as hepatitis, cirrhosis, fatty liver disease, and liver cancer. He investigates the basic mechanisms of liver inflammation and the changes in neurotransmission within the brain that occur in the context of liver disease. He is especially fascinated by the effects of liver damage on symptoms in liver disease, particularly fatigue. Dr. Swain studies how the liver might signal the brain, with the end result that the person feels tired. Fatigue is the symptom most commonly mentioned by people with liver disease, but its cause is a puzzle. Since fatigue is an unspecific symptom (in other words, it can be caused by a variety of health problems), it is difficult to determine whether it is caused by the liver disease or by something else, or by a combination of factors. This is one reason why fatigue is difficult to study, understand, and treat. Peripheral fatigue Many people with very severe liver disease suffer what is called peripheral fatigue as a result of muscle atrophy. Patients with less severe disease often experience fatigue not related to muscle deterioration: that is, fatigue that comes from changes occurring within the brain. The severity of the fatigue in these individuals does not relate to their liver function. This means that some people who have severe liver damage may not feel tired at all, while others with minimal liver damage may feel totally exhausted. “Fatigue can be the main feature of many forms of liver disease, and can be anywhere from mild and trivial to completely incapacitating,” explains Dr. Swain. “The thing that’s most difficult is that there’s no correlation between the severity of the fatigue and the severity of the liver disease. Some people will say, ‘If I have cirrhosis, why do I feel so good?’ Others will say, ‘Why do I feel so bad?’ I think, inherently, some people are more tired than others because of the different ways individuals adapt to the signals which their bodies are sending to their brain.” Dr. Swain hopes that his research may someday allow physicians to better target the treatment of fatigue as a symptom, improving quality of life for patients with liver disease and possibly for those with other chronic diseases as well. Dr. Mark Swain is an AHFMR Senior Scholar and a professor in the Department of Medicine at the University of Calgary. He receives funding from the Canadian Institutes of Health Research (CIHR). Selected publications Swain MG. Fatigue in liver disease: pathophysiology and clinical management. Canadian Journal of Gastroenterology 2006 Mar;20(3):181-188. Kerfoot SM, D’Mello C, Nguyen H, Ajuebor MN, Kubes P, Le T, Swain MG. TNF-a-secreting monocytes are recruited into the brain of cholestatic mice. Hepatology 2006 Jan;43(1):154-162. Back to Top