Red flag symptoms: Possible causes of unintended weight loss

Identify unintentional weight loss, advises Dr Pipin Singh

Weight loss may be the only symptom
Weight loss may be the only symptom
  • Persistent cough for >3 weeks
  • Haemoptysis
  • Haematuria
  • Change in bowel habit for >6 weeks and rectal bleeding
  • Persistent low mood for >2 weeks
  • Gradually worsening memory problems
  • Polyuria, polydipsia
  • Unexplained fatigue
  • Persistent lymph nodes, night sweats
  • History of unexplained persistent fever and recent foreign travel
  • Postmenopausal, intermenstrual or postcoital bleeding
  • Any reported breast lumps
  • Vomiting, dysphagia or odynophagia

Weight loss can be a manifestation of serious underlying pathology. It may present as a sole symptom or be found in the systemic enquiry and is defined as a loss of 5% of total body weight over the past month.

The aetiology is unlikely to be discovered in a 10-minute consultation and may require follow-up consultations and/or referral.

It is important to clarify whether the loss is intentional or not. Intentional weight loss may not require further investigation, but unintended weight loss will require a detailed history and examination.

If the patient has lost weight unintentionally, explore their ideas, concerns and expectations, to allow your management plan to reflect them.

Possible questions to ask the patient

  • How much weight have you lost and in what period of time?
  • Why do you think you are losing weight?
  • Do you have a reduced appetite?
  • Have you changed your diet?
  • Have you noticed any respiratory symptoms - persistent cough, dyspnoea, haemoptysis, chest pain?
  • Have you noticed any GI symptoms - abdominal pain, dysphagia, odynophagia, reflux, change in bowel habit or rectal bleeding?
  • Have you noticed any urological symptoms - haematuria or lower urinary tract symptoms?
  • Have there been any neurological symptoms, such as headache, or focal neurological symptoms?
  • Ask about breast lumps and in postmenopausal women, any history of postmenopausal bleeding.
  • It may also be important to clarify smear history and any history of postcoital or intermenstrual bleeding in women of reproductive age.
  • Check for any endocrine symptoms that may suggest thyrotoxicosis or diabetes.
  • Has there been any recent life trauma that may have precipitated the problem, such as a bereavement?


A detailed systemic enquiry may be relevant. It may be important to screen for depression and anxiety if a psychological cause of weight loss is suspected, with a cognitive screen if the weight loss is thought to be due to underlying dementia.

Weight loss may also be a result of infection, such as TB and HIV, so appropriate questions may be relevant, such as history of fever, or recent foreign travel. Skin lesions may be subtle and metastatic lesions may result in the problem, so ask about any changing lesions.

Haematological conditions such as leukaemia and lymphoma may present with weight loss. Complete the history to ensure you have a record of all medications, particularly any that may induce weight loss.

A detailed family history may be relevant, as well as smoking and alcohol history.

Possible causes

  • Malignancy of any organ/system, ranging from focal to metastatic disease
  • Infection, such as TB or HIV
  • Dementia of any type
  • Psychological conditions, such as anxiety, depression or eating disorder
  • Endocrine causes, such as diabetes or thyrotoxicosis
  • Drugs such as glucagon-like peptide-1 analogues, OTC orlistat
  • Ageing
  • Malnutrition secondary to alcohol excess and other lifestyle factors
  • Malabsorptive conditions, such as coeliac disease and parasitic infections
  • Inflammatory bowel disease
  • Autoimmune conditions, such as rheumatoid arthritis and systemic lupus erythematosus

Examination and investigations

Examination will be guided by the history. First, weigh the patient to obtain an accurate baseline weight.

Be prepared to examine a variety of systems and signpost the patient accordingly. Investigations will depend on the symptoms.

Be cautious interpreting tumour markers as they are not recommended in the primary care setting, due to their lack of sensitivity and specificity. CA-125 has been approved by NICE for detecting ovarian cancer.


  • Baseline weight and BMI
  • FBC, ferritin, tissue trans-glutaminase, U&Es, LFTs, HbA1c, TSH, ESR, calcium
  • PSA, CA-125, HIV, anti-cyclic citrullinated peptide, autoantibody screen
  • Chest X-ray
  • Urinalysis
  • Mini Mental State Examination, Six Item Cognitive Impairment Test, GP assessment of cognition
  • Ultrasound abdomen, pelvis
  • Hospital Depression and Anxiety score
  • Faecal calprotectin if irritable bowel disease is suspected


Referral will depend on the clinician's level of concern as to the aetiology of the perceived problem. It may be necessary to gather more information and follow-up in primary care may be appropriate, reviewing the patient with results and a further weight measurement to see objectively how things are progressing.

If a malignancy is suspected, refer the patient to the relevant specialty under the two-week rule.

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  • Dr Singh is a GP in Northumberland

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