ABSTRACT
Fatigue is the commonest symptom in advanced disease and patients view it as more troublesome than pain, nausea or vomiting. Reduced alertness may be due to drowsiness but can be due to causes that make patients less aware of their surroundings. Lethargy can be used to describe low mood or depression, but may also be used to describe fatigue or weakness. Patients deteriorating day by day because of their underlying disease often have fatigue, drowsiness, lethargy or weakness. Chemicals produced by tumors may partly mediate fatigue. Lambert-Eaton myesthenic syndrome is an autoimmune disease that causes a proximal weakness that improves after sustained contraction or with cold. Depression is strongly associated with lethargy and fatigue, while an anxiety state can cause fatigue through constant physical arousal. Psychostimulants such as methylphenidate are occasionally used to achieve a rapid effect when this is needed for a special event, but anxiety, anorexia and insomnia can occur.
