Fatigue - Part 2

What causes fatigue?

There are numerous potential causes of fatigue as a major complaint. They range from those that cause poor blood supply to the body's tissues to illnesses that affect metabolism, from infections and inflammatory diseases to those that cause sleep disturbances. Fatigue is a common side effect of many medications. While numerous patients with psychological conditions often complain of fatigue (physical and mental), there are also a group of patients where the cause of fatigue is never diagnosed.

What are the signs and symptoms of fatigue?

Fatigue is a symptom of an underlying disease and is described in many ways from feeling weak to being constantly tired or lacking energy.

There may be other associated symptoms depending upon the underlying cause.

• Individuals with heart disease, lung disease, or anemia may complain of associated shortness of breath or tiring easily with minimal activity. 
  
• Persons with diabetes may complain of polyuria (excess urination), polydypsia (excess thirst), or change of vision. 
  
• Those who have hypothyroidism may also have symptoms of feeling cold, dry skin and brittle hair.

It is important that the health care practitioner consider the complaint of fatigue in the context of the whole patient to try to come to an accurate causative diagnosis.

What is the treatment for fatigue?

Since fatigue is a symptom of an underlying condition, the treatment depends upon the condition that is causing the fatigue, regardless of whether it is physical, psychological or a combination of the two.

There may be a lag time between when the illness has been treated and the intensity of fatigue symptoms; some symptoms may resolve as soon as the underlying condition is treated. For example, individuals who are anemic feel much better as soon as their red blood cell count increases, while those recovering from infectious mononucleosismay require weeks to have their energy levels return to normal.

Can fatigue be prevented?

Fatigue as a symptom can occur as the result of many causes and therefore, prevention is not an issue. More importantly, the early recognition of fatigue will allow a person to seek medical care and potentially have an earlier diagnosis of the underlying cause made.

Sometimes, symptoms like fatigue arise gradually and it is difficult for the person to realize that there is a problem. It may take an outside perspective from a friend or family member to appreciate a difference in function. Self-awareness of gradual decline in body performance is often difficult as a person makes repeated small accommodations to complete daily activities.

Fatigue At A Glance

• Fatigue (either physical, mental or both) is a symptom that may be difficult for the patient to describe and words like lethargic, exhausted and tired may be used.
  
• Taking a careful and complete history is the key to help making the underlying diagnosis of the cause for the symptom of fatigue, However, in about a third of patients the cause is not found and the diagnosis is not known.
  
• There are numerous causes of fatigue symptoms. Examples of some treatable causes of fatigue include anemia, diabetes, thyroid disease, heart disease, COPD and sleep disorders (Table).
  
• Long lasting complaints of fatigue does not equate to chronic fatigue syndrome. Specific criteria as set by the CDC need to be met to make that particular diagnosis.