Systemic Lupus Erythematosus (SLE), commonly known as lupus, is a chronic autoimmune disease where the body’s immune system mistakenly attacks its own healthy tissues. This can affect various organs and systems, leading to a wide range of symptoms. Weight loss can be a puzzling and concerning symptom for some, signaling underlying processes related to the disease’s activity. This article explores the various reasons behind this phenomenon.
Chronic Inflammation’s Impact
Chronic inflammation, a hallmark of active lupus, is driven by an overactive immune response. This persistent inflammation increases the metabolic rate as the body expends more energy fighting the disease. This heightened energy demand can break down fat and muscle tissue, a process known as catabolism.
Pro-inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6), play a significant role in this metabolic alteration. Elevated levels of these cytokines are observed in individuals with active lupus. These molecules influence how the body processes energy, contributing to tissue wasting and weight loss.
Digestive System Effects
Lupus can affect the gastrointestinal (GI) system, impacting nutrient intake and absorption. Inflammation can occur in various parts of the digestive tract, sometimes referred to as lupus enteritis or mesenteric vasculitis. This inflammation can lead to symptoms like nausea, vomiting, abdominal pain, and diarrhea.
These GI symptoms can reduce appetite, leading to decreased food intake. Inflammation in the intestines can also impair nutrient absorption, even with adequate food intake. Both reduced intake and malabsorption contribute to a caloric deficit and weight loss.
Treatment Side Effects
While some medications used to manage lupus, such as corticosteroids, can cause weight gain due to fluid retention or increased appetite, other treatments may lead to weight loss. Immunosuppressants, such as mycophenolate mofetil and azathioprine, are prescribed to control lupus activity. These medications can have gastrointestinal side effects, including nausea, vomiting, diarrhea, and loss of appetite.
These medication-induced symptoms can reduce caloric intake, leading to weight loss. Non-steroidal anti-inflammatory drugs (NSAIDs), used for pain and inflammation, can also cause stomach upset, nausea, and affect appetite. The cumulative effect of these side effects can contribute to weight loss.
Wasting and Altered Metabolism
Prolonged chronic illness, like lupus, can lead to cachexia, a severe state of involuntary weight loss and muscle wasting. Cachexia differs from simple starvation because it involves complex metabolic shifts not easily reversed by increased caloric intake. It is characterized by a loss of both muscle mass and fat tissue.
The body’s metabolism can shift into a catabolic state, where tissue breakdown outpaces synthesis, even with nutritional support. Energy is prioritized for the immune response, leading to persistent tissue breakdown. Fatigue, common in lupus, can also reduce physical activity, contributing to muscle loss and wasting.