Fatigue versus weakness

It is important to discriminate between weakness and fatigue. Often, patients describe muscle weakness when speaking about fatigue such as, “I am tired all the time and I feel weak.” In children with weakness, parents will say the child is floppy or “doesn’t run in gym like the other children.” An individual tends to tire easily with metabolic or neuromuscular diseases, such as hypothyroidism or myasthenia gravis.

Young children tend not to have vocabulary that describes fatigue; often it is the parent who brings the child to the clinic. Parents may state that the child is “lying around” or “I can’t get the child to do anything” or “she just doesn’t have any energy.” Adolescents will say they are “always” tired.

Lifestyle habits

A history of the patient’s daily living and working habits may reveal a physiological cause for exhaustion. Erratic eating patterns, dieting, and missed meals may result in undernutrition or overnutrition. High levels of caffeine can affect the amount of energy a person has and can affect the sleep cycle, causing fatigue. Academic stress, athletic participation, and employment further contribute to fatigue in adolescents.

Sleep pattern

Lack of adequate amounts of sleep is often the cause of fatigue (see Chapter 28). Adults need at least 6 to 8 hours of sleep for adequate rest; adolescents, 8 to 9 hours; and children, 10 hours. Patients with sleep apnea, which is more common in men older than 45 years, may report waking up and not being refreshed. Heart failure causes postural nocturnal dyspnea, leading to difficulty breathing at night and disturbed sleep. Early morning wakening is a symptom of depression, as is excessive sleeping during the day.

Last normal menstrual period

Fatigue is a common symptom in women. Fatigue is an early sign of pregnancy, a symptom post childbirth, and a symptom associated with menopause. Perimenopausal women may have fatigue as a result of disrupted sleep because of night sweats or hot flashes.

Exposure to body fluids

Fatigue may be the initial and most prominent symptom of hepatitis, human immunodeficiency virus (HIV) infection, or acquired immunodeficiency syndrome (AIDS). Hepatitis B can be a sexually transmitted infection through semen or contracted from exposure to contaminated blood. Sexual practices that traumatize mucous membranes, such as anal intercourse, increase the risk of transmission of organisms. The person with HIV/AIDS experiences cognitive impairment that includes difficulty processing complex information. These impairments are correlated with the severity of fatigue.

Medications

Almost any drug can have fatigue as a side effect. The most common drugs that cause fatigue are antihypertensive drugs, cardiovascular medications, psychotropic medications, and opiates. Side effects also occur with drugs such as sedatives and antihistamines. Many drugs that cause fatigue are over-the-counter preparations.

Alcohol and drug use

Alcohol abuse and use of illicit drugs may be overlooked as a cause of chronic fatigue in adolescents and school-age children. This fatigue is due directly to the substance, usually alcohol or marijuana, and to secondary factors such as associated poor lifestyle habits related to sleep, rest, and nutrition. Family and friends may express the greatest concerns about fatigue that affects the patient’s ability to function. The CAGE questionnaire is a useful screening tool to assess for alcohol abuse (see Box 3-3).

Appetite

An increased appetite may indicate hypoglycemia. A decreased appetite may indicate an infectious process.

Weight loss

Weight loss may indicate malignancy, infection, or poor nutrition related to depression or lack of information about a healthy and balanced diet.

Increased urination

Diabetes mellitus, especially type 2, often presents with fatigue along with polydipsia, polyphagia, and polyuria.

Joint tenderness

In children with juvenile rheumatoid arthritis (JRA), severe fatigue that seems to be more than expected with the degree of joint involvement is seen. In young and middle-aged patients, chronic fatigue syndrome can involve multiple tender points on the body that are over joints.

Associated symptoms

Psychological fatigue is often associated with nonspecific and multiple symptoms, such as muscle aching, abdominal pain, and general lethargy. Organic causes of fatigue are associated with a few specific symptoms that worsen over time, such as dry skin and nails with hypothyroidism or shortness of breath with exertion or when lying flat with congestive heart failure.

Occupational exposure

Heavy metals and pesticides may cause fatigue and other neurological symptoms. Soldiers returning from combat zones, such as the Gulf War, have been found to have unrelenting fatigue from an unknown cause.

Camping

Lyme disease is carried by the deer tick and may present with a history of weeks of malaise and chronic fatigue before any skin manifestations appear.

Onset and pattern

The onset of psychological fatigue is often related to a stressful event and may have a sudden onset. Fatigue associated with metabolic causes may have a slow and progressive onset. Significant fatigue is considered to last more than 2 weeks and is experienced by about 25% of adults. Fatigue may be an early sign of pregnancy.

Severity

Clinically significant fatigue may vary throughout the day but never completely disappears. Children with Lyme disease and JRA experience severe fatigue that is in excess of the degree of disease involvement. The patient may need to limit social functioning and recreational activities as a result of fatigue, which may then exacerbate mood disturbances, which in turn contributes to fatigue.