Loss Of Appetite
Loss of appetite (anorexia) commonly accompanies a range of pathological conditions. Especially in the elderly, who make up a considerable part of the internal medicine patients, anorexia can occur even in many trivial diseases.
Virtually every infection, whether viral or bacterial, associated with fever is accompanied by loss of appetite. Anorexia typically occurs in infections affecting the digestive tract (e.g. infectious stomach inflammation), when the patient suffers with nausea and vomiting.
Generalized cancers (i.e. cancers that have spread throughout the body) are almost always associated with loss of weight and loss of appetite. It is caused by production of pro-inflammatory substances in immune system defense reaction.
Loss of appetite virtually always accompanies right-sided heart failure. Disruption of heart pumping function causes blood accumulation in venous system in the body including veins of gastrointestinal tract. This interferes with absorption of nutrients and reduces appetite. The technical term for this condition is cardiac anorexia. In advanced stages of heart failure, anorexia may be a serious problem that can devastate the affected organism.
Long-term inadequate function of these organs is related to accumulation of waste products of our metabolism. These substances have negative overall effect on the brain including reduced appetite.
These diseases may be associated with inflammatory processes affecting the entire body. Many inflammatory substances are produced that have generally negative effects – they may cause fatigue, night sweats, anorexia and weight loss.
Polypharmacy means taking too many medications. This is an increasing problem of modern internal medicine, because many polymorbid patients of advanced age use daily ten or more pharmaceutical products. Interactions among so many drugs are unpredictable and often lead to nausea and loss of appetite.
Digestive tract disorders
This is a very broad group of diseases is affecting the digestive tract (esophagus, stomach, bowels, biliary tract, liver, pancreas, etc). Quite a good overview of these conditions can be found in the article dedicated to abdominal pain. Virtually all causes of abdominal pain are also associated with reduced appetite.
Psychic factors may be associated with loss of appetite. Depression and anxiety disorders are very common causative factors of anorexia, especially by older women. Dementia present in the elderly is also a contributing factor to inadequate food intake. In young girls and women there are two main psychic conditions related to food intake disruption – anorexia nervosa and bulimia.
Investigating symptom such as loss of appetite is very difficult. Given the vast number of possible causes it is necessary to start with cautious medical history (other present symptoms, known diseases, current medication, etc.) and physical examination.
Blood tests may reveal information about alimentary condition of the patient, about inflammatory processes (high sedimentation rate and CRP) and about important organs’ function (liver tests, renal parameters).
At least basic imaging methods should be also done, for example chest X-ray and abdominal ultrasound. If there is suspicion of a heart disorder, echocardiography is the appropriate examination. Many organic diseases of the digestive tract can be diagnosed from stool examination, upper GI endoscopy and colonoscopy. Additional diagnostic approach usually depends on outcome of above mentioned methods.