Catabolic Wasting - Cachexia and Sarcopenia
Symptoms and Diagnosis
Most people with cachexia or sarcopenia experience weakness, fatigue, and difficulties in daily living. There is not yet a consensus as to how to determine when catabolic wasting reaches the point of cachexia or sarcopenia. In 2008, cachexia was defined as “a complex metabolic syndrome associated with underlying illness and characterized by loss of muscle with or without loss of fat mass” (Evans 2008). In 2010, a proposed definition of sarcopenia was based on age-related loss of muscle mass, handgrip strength, and walking speed (Cruz-Jentoft 2010).
There is large overlap between cachexia and sarcopenia, and it may be difficult to clinically distinguish between the two (Rolland 2011; Fearon 2013; Muscaritoli 2013). Many aging individuals may experience both cachexia and sarcopenia simultaneously (Rolland 2011; Fearon 2013; Muscaritoli 2013).
While it may be difficult to define a precise point where significant muscle wasting begins, moderate to severe cachexia and/or sarcopenia can be diagnosed by observing loss of muscle mass, strength, and tone in the person. Recently, some researchers have proposed that cachexia and sarcopenia should be diagnosed by calculating lean and fat body mass by imaging techniques such as MRI (magnetic resonance imaging) (Fearon 2013).
Pre-cachexia and the Importance of Early Recognition of Catabolic Wasting
Loss of body mass and muscle strength often occur gradually among individuals with slowly progressing, chronic diseases as well as aging populations typically considered otherwise healthy. This often precludes recognition of the early stages of wasting and results in missed opportunities for preemptive intervention that may help patients maintain better functional capacity and quality of life in the long term (Norman 2008; Muscaritoli 2010).
Estimates suggest as many as 50% of hospitalized individuals are malnourished (Norman 2008). More concerning still, nutritional status very often worsens during hospitalization, owing to the under-recognition and under-treatment of early signs of wasting by physicians and hospital staff (Norman 2008). Malnourished patients typically require longer hospital stays and have worse prognoses for both acute and chronic illnesses (Norman 2008).
The harsh reality is that medical care providers often fail to address early signs of wasting until it has reached advanced stages, at which point the efficacy of interventions aimed at improving body composition is considerably impaired (Norman 2008; Muscaritoli 2010).
Fortunately, recent collaborative research efforts have focused on the critical need to recognize and address wasting and cachexia in earlier stages. In 2010, specific guidelines on the recognition and classification of “pre-cachexia” were developed. These guidelines established the following requisites for the diagnosis of pre-cachexia (Muscaritoli 2010):
- underlying chronic disease;
- unintentional weight loss ≤5% of usual body weight during the preceding 6 months;
- chronic or recurrent systemic inflammatory response;
- anorexia or anorexia-related symptoms.
The hope is that these guidelines will usher better management of nutritional status among individuals with early stage wasting and help avert the decline in health linked to advanced stages of wasting and cachexia. Patients, their families, and their health care providers should all remain cognizant of the pivotal role that maintaining adequate nutritional status plays in aiding recovery from illness and prolongation of health span. Even small changes in body composition or eating habits among aging and chronically ill individuals should not be overlooked, as early nutritional intervention may stave off subsequent declines in quality of life and improve patient outcomes (Muscaritoli 2010; Norman 2008).