When weight loss occurs without any conscious changes made in lifestyle, physical activity, or diet, it is termed unintentional weight loss. A certain amount of fluctuation in weight is natural. However weight lost unintentionally is concerning or significant in the following situations:
- If more than 5% of one’s weight is lost within 6-12 months.
- Weight loss is obviously visible to self and others
- There is accompanying weakness, fatigue, and lost work capacity
In case of unintentional weight loss that is significant and of concern, it is important to find the cause, and rule out certain underlying medical conditions.
Psychological: Often there is a psychological issue underlying unintentional loss of weight. This can include depression, anxiety, and stress. Reduced sleep is also a very important, often overlooked cause. Eating disorders like anorexia nervosa should also be evaluated for in younger patients.
Metabolic: Weight loss can be a presentation of diabetes which should always be ruled out. Thyroid disorders may be another common cause. Other endocrine disorders may be rarely the reason like adrenal insufficiency, etc.
Digestive: Improper digestion and absorption of nutrients, due to conditions of the gastro-intestinal (GI) system, can often lead to weight loss. This can include inflammatory bowel disease (IBD – Crohn’s disease and ulcerative colitis), malabsorption syndromes (like sprue, coeliac disease), food allergies, chronic or recurrent GI infections, irritable bowel syndrome (IBS) with diarrhea, acidity and peptic ulcers, GI obstruction/stricture, swallowing difficulty (dysphagia) or dental problems/mouth ulcers, etc. Liver disease, as well as gall bladder inflammation or stones, or pancreatitis can also be a cause. Symptoms like abdominal pain, diarrhea, vomiting, indigestion, loss of appetite, etc. should be enquired for, and sometimes GI imaging by ultrasound or endoscopy maybe needed.
Infections –Tuberculosis (TB) is one of the common causes of weight loss in developing countries like India, and should be investigated for in all cases on unintentional weight loss. HIV infection can manifest as weight loss before any other symptom, so should always be tested for and ruled out. Sometimes respiratory tract infections (flu, recurrent cold and cough, and COVID) as well as recurrent urinary tract infections (UTI) can also lead to weight loss.
Heart and Lung Disease: Certain chronic conditions of the heart and lung can often be associated and underlying. These include heart failure, chronic obstructive pulmonary disease (COPD), and interstitial lung disease (ILD).
Drug/Medicine/Substance Abuse: This is one of the most common causes that include too much intake of alcohol, narcotic drugs, or even prescription drugs like antibiotics, pain-killers, and others.
Electrolyte levels: Low sodium or high calcium levels, both can be underlying associations with weight loss.
Cancer: Any malignancy or tumor in the body can lead to weight loss, and this may sometimes be the only visible or early symptom of the cancer. High index of suspicion with regards to lifestyle, personal and family history, age and other risk factors will help pick up cancers early. Recommended cancer screening tests also help.
Autoimmune and other conditions – Conditions like lupus, rheumatoid arthritis and other autoimmune conditions can be rarer causes of loss of weight. One must enquire for other symptoms. A relatively rare condition called amyloidosis that is build-up of abnormal amyloid deposits in the body organs like heart, brain, kidneys, spleen, etc. can also manifest as weight loss.
Note: Cachexia is a term used to describe ill health involving marked weight loss, characterized by muscle mass loss.
HISTORY: A complete history of diet, lifestyle, physical activity, personal medical history, family history, and a detailed enquiry into accompanying symptoms, is taken by the physician. Menstrual history in women must be enquired for as weight loss in women may be an association with both period problems, or menopause.
PHYSICAL EXAMINATION: Thereafter a thorough physical examination is important, including weight/height check, blood pressure, mouth examination, chest auscultation, abdominal examination, and looking for enlarged lymph nodes or swellings.
PSYCHOLOGICAL EVALUATION: This is often overlooked but very important. In elderly it is often the main cause of weight loss. This should include mood, stress, sleep, and cognition.
INVESTIGATIONS: All routine blood investigations should be done including complete blood counts, sugar check, kidney and liver function tests, lipid profile, thyroid function tests, blood proteins and electrolytes, and markers of cancer, autoimmune or other diseases when clinical suspicion is present. Specific blood tests for HIV, TB and other infections when suspected may also be performed. A urine and stool test may also be ordered for. A chest X ray is routinely performed, and when necessitated by history and symptoms, additional imaging tests like ultrasound, endoscopy or CT/MRI may be ordered.
TREATMENT: This is usually done by treating the underlying condition, with supportive nutritional and psychological care. Therefore, management requires a holistic approach with a multispecialty team of a physician (with specialists depending on clinical condition – cardiologist, pulmonologist, neurologist, gastroenterologist, oncologist, etc.) along with a nutritionist, physical therapist and psychologist.
See ideal weight calculator for reference