Cachexia

Cachexia is a complex metabolic syndrome associated with underlying illness and characterized by loss of muscle with or without loss of fat mass. The prominent clinical feature of cachexia is weight loss in adults or growth failure in children. Cachexia is distinct from starvation, age-related loss of muscle mass (sarcopenia), primary depression, malabsorption, and hyperthyroidism.

Etiology

Cachexia is commonly associated with chronic diseases such as cancer, chronic obstructive pulmonary disease (COPD), chronic kidney disease, chronic heart failure, and acquired immunodeficiency syndrome (AIDS). The pathophysiology of cachexia involves a complex interaction between pro-inflammatory cytokines, neuroendocrine hormones, and metabolic abnormalities.

Pathophysiology

The pathophysiology of cachexia is multifactorial and involves:

• Increased levels of pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1 (IL-1).
• Altered metabolism of carbohydrates, proteins, and fats.
• Increased muscle protein degradation and decreased muscle protein synthesis.
• Anorexia and reduced food intake due to the effects of cytokines and other factors on the central nervous system.

Clinical Features

The clinical features of cachexia include:

• Significant weight loss over a short period.
• Muscle wasting and loss of muscle strength.
• Fatigue and weakness.
• Anorexia and reduced food intake.
• Edema in some cases.

Diagnosis

The diagnosis of cachexia is primarily clinical and based on the presence of significant weight loss and muscle wasting in the context of an underlying chronic disease. Diagnostic criteria may include:

• Unintentional weight loss of more than 5% of body weight over 6-12 months.
• Body mass index (BMI) less than 20 kg/m² in adults.
• Reduced muscle strength and physical performance.

Management

The management of cachexia involves a multidisciplinary approach, including:

• Nutritional support to increase caloric and protein intake.
• Pharmacological interventions such as appetite stimulants, anti-inflammatory agents, and anabolic agents.
• Physical exercise to improve muscle mass and strength.
• Treatment of the underlying disease to reduce the inflammatory response.

Prognosis

Cachexia is associated with poor prognosis and increased mortality, particularly in patients with advanced cancer and chronic heart failure. Early recognition and intervention are crucial to improve outcomes and quality of life.

See Also

• Sarcopenia
• Anorexia
• Malnutrition
• Inflammation
• Muscle atrophy