Fatigue with an unexplained weight gain or weight loss

Unexplained weight change (gain or loss) with fatigue may occur with any of the following diseases:

• A decrease in the amount of oxygen-carrying substance (hemoglobin) found in red blood cells (anemia)
• Problems with the thyroid gland, which regulates the way the body uses energy.
  • A low thyroid level (hypothyroidism) can cause fatigue, weakness, lethargy, weight gain, depression, memory problems, constipation, dry skin, intolerance to cold, coarse and thinning hair, brittle nails, or a yellowish tint to the skin.
  • A high thyroid level (hyperthyroidism) can cause fatigue, weight loss, increased heart rate, intolerance to heat, sweating, irritability, anxiety, muscle weakness, and thyroid enlargement.
• Metabolic disorders, such as diabetes, in which sugar (glucose) remains in the blood rather than entering the body’s cells to be used for energy
• Cancer, such as lung cancer, leukemia, or lymphoma
• Infection, such as tuberculosis or HIV
• Problems with the heart, such as coronary artery disease or heart failure, which limit the supply of oxygen-rich blood to the heart muscle or the rest of the body
• Kidney disease and liver disease, which cause fatigue when the concentration of certain chemicals in the blood builds up to toxic levels
• Mental health problems, such as anxiety or depression
• Lung diseases, such as asthma or COPD
• Adrenal gland problems, such as Addison's disease or Cushing's disease
• Malnutrition
• Alcohol or drug abuse or withdrawal

Visit your health professional if your fatigue does not go away and you have an unexplained weight change.