Post #35: Unexplained Weight Loss – which pre-requisite tests are indicated before  requesting CT scans?

 Definition: Unexplained weight loss is defined as the unintentional weight loss of 10 lbs. or 5% of body weight over a period of 6-12 months.  A search for the cause is usually undertaken to find a treatable or curable etiology.  Often even an intensive search fails to disclose a cause. 

 Although weight loss is common in end-stage malignant diseases, cancer-related weight loss, presenting as the sole symptom with no other signs or symptoms related to a cancer, is quite rare.  As a result, a careful history, physical exam, followed by laboratory tests and simple x-rays and ultrasound scans, are required before undertaking a radiographic journey. 

Known causes may include

·      End-stage organ failure  (such as chronic severe congestive heart failure, emphysema, chronic kidney,

liver, or pancreatic disease)

·      Under-active hormonal diseases (hypo-thyroidism, adrenal insufficiency, uncontrolled diabetes mellitus)

·      Overactive hormonal diseases (hyperthyroidism, hyperparathyroidism)

·      Gastrointestinal, digestive, or nutritional diseases (celiac disease, Crohn’s disease, ulcerative colitis,

dental problems, changes in diet, appetite, sense of smell or taste, peptic ulcer diseases)

·      Neurological Diseases (Parkinsons, dementia)

·      Medications (prescription or OTC drugs)

·      Substance Abuse (alcohol, cocaine, others)

·      Infections:  HIV/AIDS, tuberculosis, other chronic infections)  

·      Psychological: Depression, anorexia

 These conditions should be ruled out before searching for a malignancy (unless signs or symptoms of a cancer are also present from the history and physical exam). 

 Evaluation before embarking on a CT search for cancer:

·      CBC, urinalysis

·      Chemistry Profile

·      Hormones: (TSH, Hgb A1c, ACTH, pituitary hormones, gonadal evaluation)

·      Depression scale

·      X-ray (chest) for non-smokers, (CT chest with contrast (71260) can be approved for smokers)

  • mammography

·      Upper and lower GI tract endoscopy and stool test for occult blood (if > 50 years old, colonoscopy is

required before advanced imaging).

·      Others: abdominal ultrasound, echocardiogram

 CT search for cancer:

Advanced imaging:  CT chest ((71260) and CT abdomen and pelvis (74177) is recommended if the above evaluation is not diagnostic or is equivocal. 

PET is not part of the evaluation of unexplained weight loss

 Lesson #35: Unexplained weight loss may be simplified if a logical, sequential series of diagnostic tests follows a comprehensive history and physical exam.  These include blood and stool tests, hormonal assays and simple x-rays and ultrasounds.  If these are non-diagnostic, CT scans are indicated and supported by current guidelines.