This article focuses on unintentional weight loss and not on weight lost voluntarily through exercise or dieting.
Weight loss means a reduction of the total body mass, due to a mean loss of fluid, body fat, bone mineral deposits, muscle, tendon, and other connective tissue.
Weight loss can be due to some diseases or intentional [slimming] due to a conscious effort [to improve an actual or perceived overweight or obese state.
Unintentional weight loss becomes a medical problem when at least 10% of a person’s body weight has been lost in six months or 5% in the last month.
There could be multiple causes of unintentional weight loss from malnutrition, diseases, metabolic changes or hormonal changes.
Mechanisms of Weight Loss in Disease
There could be various mechanisms for weight loss due to disease processes
- Poor appetite can be a direct symptom of an illness
- Eating is painful
- Eating induces nausea
- Food aversion due to illness
- Inability to eat due to
- Diminished consciousness
- Problems in swallowing or chewing
- Poor quality meals
- Changes to metabolic demands due to illness, surgery and organ dysfunction.
- Loss from vomiting or diarrhea
- Fluid loss in Losses fistulae, stomas and drains, skin exudates
Diseases Causing Weight Loss
Chronic obstructive pulmonary disease
In advanced obstructive lung disease about a third of patients get severe weight loss. This condition is called pulmonary cachexia, including diminished muscle mass. Additional energy required for breathing and the difficulty of eating due to breathlessness is thought to be the reason behind the weight loss.
Causes unexplained (idiopathic) weight loss. In fact, cancer is responsible for about one-third of unintentional weight losses
People with HIV often experience weight loss. Wasting syndrome is an AIDS-defining condition.
- Food intolerance
- Oral, taste or dental problems
- Painful mouth sores
- Newly applied orthodontic appliances, or loss of teeth.
- Persistent vomitings like in pyloric stenosis and hiatus hernia
- Coeliac disease
- Chronic pancreatitis
- Crohn’s disease.
- Gastrointestinal infection.
- Gastrointestinal fistulas
- Carcinoid disorders
- Intestinal hypermotility
- Hepatobiliary disease.
Some infectious diseases can cause weight loss. Tuberculosis, Fungal illnesses, endocarditis, many parasitic diseases, AIDS, and some other subacute or occult infections may cause weight loss.
Patients who have uremia often have a poor or absent appetite, vomiting, and nausea. This can cause weight loss.
Cardiovascular disease, especially congestive heart failure, may cause unexplained weight loss.
- Connective tissue disease
- Neurologic disease, including dementia
- Endocrinal Diseases
- Diabetes mellitus.
- Addison’s disease
- Gut hormone tumors
- Psychological – for example:
- Anorexia nervosa.
Increase in energy requirement occurs after surgery. A surgical procedure affects intake if the procedure alters the digestive system.
There is a history of weight loss either noted by the patient herself or pointed out by some friend or relative.
The presentation will depend on the underlying cause.
The clinical assessment includes both consideration of possible physical causes as well as careful evaluation.
Decreased levels of hemoglobin occur with chronic disease, malabsorption, chronic kidney disease, liver failure.
The raised erythrocyte sedimentation rate is a non-specific indicator of disease, malignancy, infection, connective tissue disorder.
Renal function may indicate chronic kidney disease
Blood sugar levels, liver function tests, and the hormonal assay may be done as needed.
Other investigations relevant to the patient profile may be done
X-rays, CT and MRI may be done to rule out/confirm suspected lesions.
Treatment of Unintentional Weight Loss
Unintentional weight loss is not a disease in itself. It is a sign of some underlying disorder. The underlying disease or cause should be identified and treated.