Involuntary Weight Loss Over Weeks or Months

MANUAL OF CLINICAL DIAGNOSIS

Involuntary weight loss over weeks or months is a concerning symptom that may indicate a wide range of underlying medical conditions, both physical and psychological. This weight loss is generally defined as a reduction of 5% or more of body weight over a period of 6 to 12 months without changes in diet or physical activity. Identifying the cause of weight loss is crucial to provide appropriate treatment and prevent further complications.

Pathology	Clinical Symptoms and Signs	Suspected Diagnosis	Confirmatory Diagnosis
Advanced Neoplasia	Weight loss, fatigue, localized pain, palpable masses, night sweats	Medical history, physical examination, family history	Chest X-ray, computed tomography (CT), biopsy, tumour markers
Psychiatric Disorders	Weight loss, changes in appetite, mood disorders, anxiety, social withdrawal	Medical history, psychiatric evaluation	Clinical interview, assessment questionnaires, depression and anxiety scales
Gastric Pathology	Weight loss, abdominal pain, dyspepsia, vomiting, changes in bowel habits	Medical history, physical examination, gastrointestinal history	Upper endoscopy, abdominal CT, liver function tests
Alcoholism	Weight loss, excessive alcohol consumption, hepatomegaly, jaundice, peripheral neuropathy	History of alcohol use, physical examination	Liver function tests, liver ultrasound, blood alcohol levels
Undiagnosed Diabetes Mellitus	Weight loss, polydipsia, polyuria, polyphagia, fatigue, blurred vision	Medical history, physical examination, symptoms of hyperglycaemia	Fasting blood glucose, HbA1c, glucose tolerance test
Thyrotoxicosis	Weight loss, nervousness, tremors, palpitations, heat intolerance, exophthalmos	Medical history, physical examination, hyperthyroid symptoms	Thyroid function tests (TSH, free T4, T3), thyroid scan
Pulmonary Tuberculosis	Weight loss, persistent cough, haemoptysis, fever, night sweats	Medical history, physical examination, exposure history	Chest X-ray, tuberculin skin test, sputum culture
Addison’s Disease	Weight loss, fatigue, hyperpigmentation, hypotension, nausea	Medical history, physical examination, adrenal insufficiency symptoms	ACTH stimulation test, cortisol and ACTH levels
Other Causes	Symptoms vary according to underlying pathology	Medical history, physical examination	Specific tests according to clinical suspicion