Unexplained Weight Loss

Changes in body weight that cannot be attributed to a specific cause, such as dieting or overeating, are called unexplained weight changes. Changes in weight that can be traced to a cause also may be unintentional.

Both unexplained and unintentional weight changes may involve weight loss or weight gain. Common causes of weight changes include shifts in physical activity, diet and mood. Illness and use of certain medications also can affect a person's weight. When significant weight loss or gain is not explainable by lifestyle factors (e.g., changes in diet or exercise) or temporary illness such as the flu, it may be a sign of a more serious underlying condition. Examples include diabetes, thyroid disorders, cancer, depression and heart disease.

Patients are advised to notify their physician if they notice a significant decrease or increase in weight over a short period of time. Diagnosing the cause of the weight change usually begins with a medical history and physical examination. The physician also may order a nutritional assessment, blood tests, urine tests, x-rays and other tests.

Treatment for unexplained or unintentional weight changes is directed at the cause of the change. After the underlying condition is diagnosed, the appropriate treatment can be determined.

About weight changes (unexplained)

Unexplained weight changes are fluctuations in body weight that cannot be attributed to a recognizable cause, such as dieting or overeating. In other cases, a patient's weight change can be explained, but nonetheless is unintentional and may be undesirable. Unexplained and unintentional weight changes include:

  • Weight loss. Weight loss usually occurs when individuals "burn" or expend more calories than they consume. Common causes of weight loss include increased physical activity, dietary changes, mood changes, certain medications and temporary illness (e.g., gastroenteritis).
  • Weight gain. Weight gain usually occurs when individuals consume more calories than they expend. Common causes of weight gain include lack of exercise, overeating, hormonal changes and certain medications.

When significant weight loss or gain cannot be explained by lifestyle factors (e.g., changes in diet or exercise) or temporary illness, it may be a sign of a more serious underlying condition. Numerous conditions can cause weight to fluctuate, such as eating disorders, endocrine disorders (e.g., diabetes, thyroid disease), heart disease, depression or cancer. Sometimes a condition can involve either an increase or a decrease in weight, depending on the individual. For example, depression causes many people to eat less and lose weight, whereas others eat more and gain weight.

Sources of unexplained weight loss

Illnesses and disorders are a major cause of unexplained or unintentional weight loss. The reasons for the weight loss vary. Loss of appetite (anorexia) is often involved and may be due to a wide range of factors, such as a general ill feeling (malaise), decreased activity levels, pain or hypercalcemia (excessive calcium in the blood, caused by disorders including sarcoidosis and hyperparathyroidism). However, some metabolic disorders, notably diabetes and hyperthyroidism, can cause a person to overeat but still lose weight.

Another common reason for weight loss is malnutrition. The many causes of malnutrition include intestinal obstructions, neglect of dependent individuals by caregivers, impaired swallowing (dysphagia) due to conditions such as a stroke or Parkinson's disease, or difficulty eating due to conditions such as severe rheumatoid arthritis in the hands.

Nausea and vomiting may also play a role. The many causes of nausea and vomiting range from migraines to pregnancy to pancreatitis to chemotherapy. Conditions associated with weight loss include:

  • Many cancers, including colorectal, stomach, esophageal, pancreatic and lung, and cancer treatments including chemotherapy, radiation therapy, surgery and some types of hormonal or biological therapy .
  • Other gastrointestinal and digestive problems, including chronic diarrhea, colitis, food intolerances, ulcers and some liver and gallbladder diseases .
  • Depression .
  • Eating disorders, including bulimia and anorexia nervosa .
  • Endocrine disorders including diabetes, forms of hyperthyroidism (overactive thyroid gland) such as Graves' disease, forms of hyperadrenalism (underactive adrenal glands) such as Addison's disease, and hyperparathyroidism (overactive parathyroid glands).
  • Infectious conditions, such as AIDS, tuberculosis or parasitic infection.
  • Pain conditions. Examples include chronic fatigue syndrome, lupus, migraines or other severe headaches, myositis, polymyalgia rheumatica, sarcoidosis, temporal arteritis, TMJ disorder and certain forms of arthritis, such as osteoarthritis of the jaw or ankylosing spondylitis.
  • Neurological conditions, such as amyotrophic lateral sclerosis (ALS) and Parkinson's disease.
  • Use of certain medications, including amphetamines, laxatives, some diabetes drugs (e.g., incretins, biguanides) and some thyroid drugs.

Several recent studies have found that unexplained weight loss may precede Alzheimer's disease or other forms of dementia.

Nonmedical factors also may cause unintentional weight loss. Children and others sometimes lose weight as a tactic to gain attention or sympathy. Some smokers find that tobacco use reduces their appetite.

Temporary factors also may cause unintentional weight loss. For example, people with mouth sores or acute and chronic dental problems often shy away from eating, resulting in weight loss that lasts until their oral symptoms improve. Illnesses such as the flu or common cold may temporarily reduce appetite and cause weight loss.

Sources of unexplained/unintentional weight gain

Several different factors can cause unintentional or unexplained weight gain. People gain weight when they consume more calories than they expend through activity. Common sources of unintentional weight gain include:

  • Aging. As people grow older, their metabolism slows. This puts them at increased risk for weight gain, although very elderly people often lose weight because of reduced appetite.
  • Certain endocrine disorders. These include hypothyroidism (underactive thyroid gland), Cushing's syndrome (overactive adrenal glands) and polycystic ovarian syndrome.
  • Conditions involving edema (swelling due to accumulation of fluid). Examples include heart failure, pulmonary edema and kidney failure.
  • Benign tumors and certain cancers, such as carcinoid tumors (tumors that release large amounts of serotonin and other substances) in the bile duct, pancreas, intestinal tract, lung or ovary.
  • Pregnancy and menstruation. Women who are pregnant normally gain weight, which may be in addition to that of the developing fetus. Menstruation may also cause temporary weight gain in some women.
  • Medications. These include corticosteroids, cannabinoids (marijuana-like drugs), antipsychotics and some drugs used to treat depression, bipolar disorder, diabetes (e.g., insulin, sulfonylureas), high blood pressure, seizures or heartburn. Patients are advised not to discontinue medications without talking to their physician. It is dangerous to halt some drugs abruptly or without a physician's supervision.
  • Quitting smoking.

Diagnosis and treatment of weight changes

Patients are urged to immediately notify their physician if they notice any of the following:

  • A 5 percent reduction in body weight over the course of a few weeks • •A 10 percent reduction in body weight over six months
  • A significant increase in body weight over a short period of time
  • Weight changes that exceed 5 pounds (2.3 kilograms) in a week during treatment, with perhaps the exception of weight loss associated with bariatric (obesity) surgery
  • Other symptoms that occur in tandem with the weight change

Unexplained weight changes - especially sudden, inexplicable weight loss - may be the first sign of diseases such as cancer. In order to determine the cause of the weight change, the physician will conduct a medical history and perform a physical examination.

Questions about the patient's weight changes may include: •How much weight has the patient lost or gained?

  • When did the weight change first occur
  • Was the weight change sudden or gradual?
  • Has the patient's thirst or appetite changed?
  • Have there been any changes in the patient's physical activity level?
  • Have there been any changes in the patient's bowel or bladder habits?
  • Have there been any changes in the patient's mood?
  • Was the patient recently ill?
  • Does the patient have a food allergy or dietary intolerance?
  • Does the patient have any other medical conditions?
  • What medications is the patient taking?
  • Is the weight loss accompanied by any other symptoms, such as fever, nausea or vomiting?

The physician may also order a nutritional assessment, blood tests, urine tests, imaging tests or other tests relating to the suspected cause of the weight loss.

Treatment for unexplained weight changes is directed at the cause of the weight loss or gain. In some cases, simple lifestyle changes can remedy the situation. For example, a combination of a well-balanced diet and exercise can help restore proper weight levels in people with either unintentional weight loss or weight gain.

In other cases, medical therapies may be necessary. Effective treatment of medical conditions can restore a patient's health and bring body weight back to a healthier level. Psychological counseling can help patients whose weight changes are related to conditions such as eating disorders or depression.

In extreme cases, a feeding tube may be used to help reverse unintentional weight loss, and a physician may recommend bariatric surgery to treat severe unintentional chronic weight gain that does not respond to noninvasive methods.

Questions for your doctor about weight changes

Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions about unexplained or unintentional weight changes:

1.What might be causing my weight change? Could it be due to a disease, a medication or other medical treatment, or something else?

2.How much weight do I have to lose/gain before it is considered a significant or serious amount?

3.What tests should I receive to determine the cause of my weight change?

4.Is there anything in my family or medical history that could help explain my weight change?

5.Should I be looking for any associated symptoms?

6.What can I do to stop or minimize my weight change?

7.Will I require medical treatment for my weight change? If so, what are my options, and which do you recommend?

8.Should I see a nutritionist about modifying my diet?

9.Should I also change my exercise or other habits?

10.How will I know when my weight loss/gain has been successfully reversed?

11.What is the ideal body weight for my age and gender?


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