Fatigue: Finding the Cause of a Common Complaint
There has been a great deal written in the recent past about the effects of fatigue on resident work performance. Residency programs have had to incorporate a variety of mandates in relation to resident work hours, including a maximum of 80 hours worked per week, one day off on average in seven, no more than 24 consecutive hours providing direct patient care, among others. Fatigue, however, is not something unique to residents in training. In fact, it accounts for approximately 10 million visits a year to the primary care physician, with the majority being persons over age 50. I thought it would be useful to summarize the way fatigue can be approached, as this will likely be a common problem our readers will encounter. While there is no universally accepted definition, fatigue simply is “a sensation of exhaustion during or after normal activities” or “insufficient energy to initiate an activity.”
Unfortunately, studies have shown a great deal of confusion; patients often complain of fatigue when, in fact, they have weakness, boredom, dyspnea with exertion, sleepiness, or some other problem. Weakness refers to a reduction in muscle strength and must be noted on physical examination; true weakness warrants a thorough evaluation for a neurologic or muscular cause of the patient’s complaint. In the absence of physical findings, a complaint of weakness can be considered synonymous with fatigue. Once the physician is certain that the individual is actually complaining of fatigue and not something else, fatigue can be divided into one of the following categories, listed in the order that an appropriate work-up be initiated:
Physiologic Fatigue: This form of fatigue may develop in any healthy individual under certain circumstances, such as during times of stress, change in diet, insufficient rest or inadequate sleep, or overactivity. The older person may commonly have this form of fatigue, and a thorough history can help identify issues that may help alleviate the precipitating problem so that it can be remedied.
Organic Fatigue: This form of fatigue is associated with some medical problem and is a common type in the older person. Problems such as anemia, chronic renal or liver disease, chronic obstructive pulmonary disease, congestive heart failure, infections, and a variety of endocrine/metabolic abnormalities are the most common organic causes. Work-up and treatment is based on the underlying abnormality that is found. Malignancy: Another common cause of fatigue in the older person is a malignancy. While screening tests for malignancy, such as colonoscopy and mammography, should be done on all older individuals as appropriate, a more thorough evaluation for a malignancy may be indicated if no other cause of fatigue can be identified.
Medications/Toxins: Numerous medications may cause fatigue and the older person is commonly affected, as they are the main users of medications. Clearly, use of illicit drugs and alcohol should be explored as possible explanations, but almost any medication can cause fatigue. The most commonly noted are antihistamines, analgesics, tetracycline, corticosteroids, colchicine, and beta-blockers. Fatigue may be a direct effect of a medication or a result from some disruption that the medication may cause to the normal sleep process. A temporal relationship to starting a specific medication may provide a clue to the etiology, though in certain circumstances a re-evaluation of all medications, and perhaps a trial without some particular medication or a substitution, may be warranted.
Psychogenic Fatigue: This cause of fatigue has been shown responsible for as many as 50% of cases, with depression being the most common cause. Features suggesting that fatigue is psychogenic include fatigue being present all of the time; fatigue being present upon awakening but improving later in the day; fatigue fluctuating with changes in mood or stress; and associated symptoms of depression, anxiety, or somatization.
Chronic Fatigue Syndrome is another cause of fatigue; however, it is rarely the cause of new fatigue in an older person. Specific criteria currently available to identify those with true chronic fatigue syndrome are beyond the scope of this commentary, though I suggest that all physicians familiarize themselves with them to avoid overuse of this diagnosis. No medical or psychiatric cause can be identified 30% of the time. These patients clearly need to be followed over time for the development of new signs and symptoms, and should be considered to have idiopathic chronic fatigue and be reassured. Just as in medical residents, fatigue can lead to decreased motivation, poor concentration, forgetfulness, irritability, and even depression in anyone. Psychomotor speed can be reduced, and patients may be at greater risk of falling and accidents. We must not assume that all of our older patients will complain of fatigue if questioned; we must be proactive in considering possible causes, just as we would if the complaint was chest pain or shortness of breath. The nonspecific complaint of fatigue must be taken seriously and acted upon appropriately.
Send comments to Dr. Gambert at email@example.com.