Weight Loss and Cachexia

DEFINITION
Weight loss is considered clinically important when it exceeds 10% of the normal body weight and is not associated with fluid loss.
Cachexia is defined as the state of extreme poor health and is associated with anorexia, weight loss, weakness, and mental depression.


PATHOPHYSIOLOGY
Weight loss can result from many different pathophysiologic mechanisms that share a common feature—insufficient caloric intake or availability to meet metabolic needs.
Insufficient caloric intake can be caused by (1) a high energy demand (e.g., that characteristic of a hypermetabolic state); (2) inadequate energy intake, including insufficient quantity or quality of food, or inadequate nutrient assimilation (e.g., with anorexia, dysphagia, regurgitation, or malabsorption–maldigestion disorders); (3) excessive loss of nutrients or fluid, which can occur in patients with gastrointestinal losses, glucosuria, proteinuria, or extensive skin lesions (burns, excoriations, etc.)