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EBMG

Unintentional Weight Loss in Adults

Essentials

  • Unintentional, progressive weight loss is often a sign of a serious somatic or psychological disorder.
  • The definition of significant weight loss is a loss of at least 5-10% of body weight in 6 months. In line with intentional weight loss, unintentional weight loss also results either from a decreased intake of calories or increased energy expenditure.
  • The most important somatic causes are endocrinopathies (diabetes and hyperthyroidism), gastrointestinal disorders and malignant tumours.
  • The most common psychological causes are depression and anorexia.
  • In an elderly patient, the condition of teeth, ability to eat and the regularity of meal times should be checked before other investigations are considered.

Aetiology

Endocrinological causes

  • 4-18% of the cases
  • Hyperthyroidism Hyperthyroidism
    • Weight loss is caused by increased catabolism, increased intestinal motility as well as malabsorption.
  • Diabetes
    • In recent-onset type 1 diabetes Follow-Up of Type 1 Diabetes, glucosuria causes weight loss and dehydration.
    • If diabetes is poorly controlled weight loss may result, in addition to glucosuria, from mood changes and gastrointestinal symptoms (the possibility of the late complication of gastric paresis must also be borne in mind). However, weight gain is more common in type 2 diabetes.
  • Other endocrinological causes

Gastrointestinal disorders

  • Non-malignant gastrointestinal disorders account for 10-20% of cases.
  • The mechanisms include pain, dysphagia, diarrhoea, malabsorption.
  • Coeliac disease Coeliac Disease
    • Coeliac disease is related to poor weight gain in growing children, but weight loss is not a very common symptom in adults. More commonly the patient is found to be anaemic or have other signs of malabsorption.
  • Inflammatory bowel diseases

Malignant disease

  • A malignant disease is the cause of unintentional weight loss in 19-36% of patients.
  • Cancer cachexia is associated with a variety of metabolic changes, and an increased intake of calories does not reverse cachexia.
  • Other mechanisms include anorexia, pain, nausea, malabsorption, adverse effects of treatment.
  • A baseline evaluation (general health, basic blood tests, chest x-ray, see below) is usually sufficient to suggest the possibility of a malignant disease. If the baseline tests are normal, cancer rarely is the cause of weight loss.

Infections

Other somatic disorders

  • In many cases the underlying condition has already been diagnosed, and weight loss does not pose a diagnostic challenge.
  • In old age, nutritional disorders Assessment of Nutritional Status in the Elderly are a common cause of weight loss.
    • With the help of a diet history taken by a dietitian or a food diary, the dietary cause is often discovered and unnecessary investigations are avoided.
  • Advanced heart or lung diseases (9-10%), kidney diseases (4%)
  • Neurological conditions, such as sequelae of cerebrovascular events, memory disorders, Parkinson's disease, amyotrophic lateral sclerosis (ALS)
  • Inflammatory autoimmune diseases (7%). Occasionally weight loss can be the symptom that leads to the diagnosis of temporal arteritis Giant Cell (Temporal) Arteritis or some other type of arteritis.

Psychiatric disorders

  • 9-24% of the cases
  • Depression may be as common as malignant disease in causing weight loss, depending on the age and population group.
  • Anorexia Eating Disorders Among Children and Adolescents must be identified as the cause of weight loss in a young person.
  • Weight loss may also be a feature of, for example, bipolar affective disorder and psychotic conditions.

Medication

  • The patient should be asked about the use of over-the-counter preparations, even though they are generally used knowingly for the purposes of weight loss and evidence on their effect is poor for most preparations.
  • The following prescription medicines, among others, are associated with weight loss: antiepileptics, mood-altering drugs and antidiabetics.
  • It is often difficult to differentiate between weight loss caused by the disease and the medication used in its management.

Other substance abuse

  • 8% of the cases
  • Even though alcohol is high in calories, alcoholism often leads to various states of undernourishment. Weight loss may be masked by ascites and fluid retention in liver cirrhosis.
  • Heavy smoking often results in weight loss, and weight gain is associated with smoking cessation.
  • Illicit drugs that cause weight loss include, in particular, amphetamine and other psychostimulants, opioids, cocaine and many new synthetic drugs.

Diagnostic clues

  • See table T1.

Diagnostic clues in the evaluation of involuntary weight loss

Clinical presentationDisease
History
Abdominal painPeptic ulcer, infection, tumour, coeliac disease, lactose intolerance
VomitingPeptic ulcer, obstruction
DysphagiaOesophageal tumour or ulceration, ulceration of the oral mucosa
DiarrhoeaInflammatory bowel disease, coeliac disease
ConstipationAnorexia, tumour
Faecal colourBlack: melena; light (and floating); malabsorption
SmokingLung cancer, peptic ulcer, chronic obstructive pulmonary disease
Alcohol consumptionLiver cirrhosis
Fear of gaining weight, desire to be underweight, distorted body imageAnorexia nervosa
Weight loss despite increased appetiteHyperthyroidism, recent-onset diabetes, malabsorption, significant increase in physical exercise
Use of psychotropic drugs, death of a close relative, other personal loss, stress, psychosocial situation, financial problems, poor appetiteDepression
ForgetfulnessMemory disturbances
Cough, breathlessnessTumour, infections, cardiac insufficiency, sarcoidosis
Fever, sweating, fatigueInfections, hyperthyroidism
MenstruationIf normal, significant weight loss is rare
Bone painMetastases, myeloma
HaematuriaTumour of the urinary tract
Clinical signs
Skin temperature and colour
  • Warm skin
Hyperthyroidism
  • Pigmentation
Addison's disease
  • Jaundice
Pancreatic cancer, liver diseases
  • Bruising
Thrombocytopenia, cirrhosis, cancer
  • Carotenaemia
Anorexia
Dentures, edentulismUndernourishment
Palpation of the abdomenConditions causing hepatomegaly or abdominal masses
Palpation of lymph nodesLymphoma
Digital rectal examination, type of stoolRectal tumour
Gynaecological examinationTumours

Investigation strategy

  1. History
    • Previous recordings of weight should be checked from the patient's notes, the patient should be asked whether his/her clothes feel loose and whether close relatives have noted weight loss.
    • In half of the patients the weight loss cannot be verified.
    • Anorexia can be identified on the basis of history alone.
  2. Clinical findings
    • Skin (moles, jaundice, pigmentations, enlarged veins)
    • Abdominal palpation (mass, lymph nodes, size of internal organs)
    • Breasts, gynaecological examination, prostate
    • Cardiovascular status
    • Suspicion of a neurological disorder
  3. Chest x-ray is indicated
    • Lung cancer
    • Inflammations
    • Enlarged lymph nodes (lymphoma, sarcoidosis)
  4. Laboratory tests according to the situation, e.g.
    • Full blood count, ESR, CRP
    • Fasting blood glucose
    • ALT, alkaline phosphatase
    • Blood sodium, potassium, calcium (albumin-corrected), albumin
    • TSH
    • PSA
    • Chemical urinalysis
    • Faecal calprotectin (if gastrointestinal symptoms)
    • HIV test
  5. Symptoms suggest gastrointestinal aetiology, or the above investigations have not established the cause of weight loss
    • Upper gastrointestinal endoscopy (gastroscopy) is carried out first followed by lower gastrointestinal endoscopy (colonoscopy), unless the symptoms are suggestive of a large bowel disease in which case the order of the investigations is the reverse.
    • If the endoscopic examinations fail to find a cause, imaging studies of the abdomen should be considered.
    • Before investigations are commenced in elderly patients in poor general health it should be considered whether a potential diagnosis (cancer) would change the management of the patient and whether any treatment would be beneficial to the patient.
  6. History and the above investigations have not established the cause of weight loss
    • If a specific cause is to be found, it is usually revealed with the history, clinical examination, efficiently directed laboratory tests and imaging studies or endoscopic examinations.
    • If the initial evaluation does not reveal the cause of weight loss, monitoring the patient for 1-2 years during visits to the surgery is a better option than blindly embarking on more extensive investigations.
    • The reason for the weight loss remains unknown in 6-28% of the cases.

Specialist consultation

  • Consult a dietitian, as necessary, at an early stage.
  • If anorexia nervosa is suspected, the patient is preferably referred to an adolescent psychiatry clinic, provided that the patient's general health is good.
  • A referral is warranted if unexplained weight loss is accompanied by symptoms, deteriorating health or findings that may be suggestive of an organic disease.
  • A depressed patient is referred to the care of mental health services as per local care protocols.

    References

    • Vanderschueren S, Geens E, Knockaert D et al. The diagnostic spectrum of unintentional weight loss. Eur J Intern Med 2005;16(3):160-164. [PubMed]
    • Wong CJ. Involuntary weight loss. Med Clin North Am 2014;98(3):625-43. [PubMed]