Unexplained loss of muscle mass, also known as cachexia, is a complex metabolic disorder characterized by progressive and involuntary weight loss. It is associated with an underlying illness and involves the loss of both adipose tissue and lean body mass, particularly skeletal muscle.
Common causes include chronic diseases like cancer, chronic obstructive pulmonary disease (COPD), congestive heart failure, chronic kidney disease, and HIV/AIDS infection. The exact mechanisms behind cachexia are not fully understood but likely involve a combination of reduced food intake and metabolic abnormalities that promote muscle wasting.
Key features of cachexia include:
- Weight loss of at least 5% within a span of 12 months or less
- Loss of muscle mass (with or without loss of fat mass)
- Underlying chronic illness
Cachexia significantly impacts quality of life, ability to respond to medical treatment, and mortality risk. Addressing the primary disease is the most effective initial approach. Other supportive treatments focus on increasing calorie and protein intake to counteract metabolic abnormalities and prevent further wasting. These may include
dietary counseling, oral nutritional supplements, appetite stimulants, and in some cases tube feeding. Newer pharmacological treatments that target inflammatory pathways also show promise for cachexia management.
Identifying and appropriately treating cachexia requires a multidisciplinary effort between the patient, their family, and healthcare team. The ultimate goals are to improve quality of life, preserve muscle function, and optimize the response to primary disease treatment.