Kachexia

Kachexia, more commonly spelled cachexia in English, is a complex metabolic syndrome characterized by involuntary weight loss, muscle wasting, and loss of appetite that occurs in the setting of chronic disease. It is not simply malnutrition from inadequate intake; it reflects altered metabolism and inflammation that drive tissue wasting even when calories are available.

Cachexia is most often associated with cancer, chronic kidney disease, heart failure, chronic obstructive pulmonary disease, liver disease, HIV/AIDS, and inflammatory or autoimmune conditions. It is a major cause of functional decline and is linked to increased mortality across several diseases.

Pathophysiology involves a persistent inflammatory state with cytokines such as TNF-α, IL-6, and other mediators that promote catabolism. Activation of the ubiquitin-proteasome system leads to accelerated skeletal muscle loss; there is impaired anabolic signaling, reduced appetite, and disturbances in energy balance and mitochondrial function.

Diagnosis relies on a pattern of weight loss and muscle wasting, typically with criteria such as involuntary weight loss of more than 5% over 6–12 months, or a body mass index below 20 with ongoing weight loss, or objective evidence of sarcopenia with reduced function. Assessment may include measurement of muscle mass, strength, and appetite, together with evaluation of the underlying disease.

Management is multidisciplinary. It focuses on treating the underlying illness, providing nutritional support, and encouraging physical activity or resistance training to preserve muscle. Pharmacologic approaches—such as appetite stimulants or anti-catabolic agents—are used selectively and evidence varies. Early recognition and integrated care can improve quality of life and may modestly affect survival.