Systemic Lupus Erythematosus (SLE), commonly known as lupus, is an autoimmune disease where the immune system mistakenly attacks healthy tissues, leading to widespread inflammation. This chronic condition primarily affects the joints, skin, kidneys, and nervous system, but it can also involve the gastrointestinal (GI) tract. Lupus can definitively cause stomach pain, which is often intense and complex to manage. The origins of this abdominal pain are multi-layered, stemming from active inflammation, side effects from necessary treatments, or related secondary conditions. Understanding the cause is crucial because the severity can range from mild discomfort to life-threatening complications.
Direct Gastrointestinal Involvement from Lupus
Active lupus disease, particularly during a flare, can directly attack the blood vessels and tissues of the abdomen, leading to severe pain. This direct involvement is a serious manifestation, often referred to as lupus enteritis or lupus mesenteric vasculitis. The primary mechanism involves systemic inflammation targeting the small blood vessels supplying the intestines.
Lupus vasculitis causes inflammation of these blood vessels, restricting blood flow to sections of the bowel. This reduced blood supply, known as ischemia, causes severe, cramping, and diffuse abdominal pain that can be life-threatening. Imaging studies often show characteristic signs like bowel wall thickening or a “target sign” due to edema.
Lupus enteritis refers to the resulting inflammation and edema of the intestinal wall, most commonly in the jejunum and ileum. This inflammation causes symptoms like nausea, vomiting, diarrhea, and significant abdominal discomfort. In rare but serious cases, lupus can also cause peritonitis, the inflammation of the peritoneum. This condition leads to sharp, generalized abdominal pain and may be accompanied by ascites, a build-up of fluid in the abdomen.
Medication Side Effects Causing Stomach Pain
While lupus causes abdominal inflammation, many medications used to manage the disease can also irritate the digestive system, leading to stomach pain. Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) are frequently used for pain and inflammation but carry a significant risk of gastrointestinal complications. These drugs can erode the protective lining of the stomach, potentially causing gastritis, peptic ulcers, and internal bleeding.
Corticosteroids, such as prednisone, are powerful anti-inflammatory agents used to treat lupus flares but are associated with stomach issues. Steroids increase the risk of developing ulcers, especially when combined with NSAIDs. Immunosuppressive medications, including azathioprine and mycophenolate, are used to control the immune system but may cause general gastrointestinal distress. These side effects commonly include nausea, vomiting, and diarrhea, which can result in cramping and abdominal pain.
Related Conditions Common in Lupus Patients
Abdominal pain in people with lupus is not always the result of a direct flare or medication side effect; it can also be due to other conditions common in this patient population. Pancreatitis, or inflammation of the pancreas, is one such disorder that causes severe upper abdominal pain that may radiate to the back. This condition can be a direct manifestation of lupus or a side effect of certain medications, particularly high-dose steroids or azathioprine.
Immunosuppressive treatment makes people with lupus more vulnerable to various infections, which can cause abdominal pain. Infections, whether bacterial or viral, can lead to gastroenteritis, an inflammation of the stomach and intestines, resulting in pain, vomiting, and diarrhea. People with lupus are also more likely to experience general gastrointestinal issues, such as Irritable Bowel Syndrome (IBS), which causes chronic abdominal pain, bloating, and changes in bowel habits.
Recognizing Symptoms That Require Immediate Medical Attention
Given the wide range of causes, some of which are life-threatening, recognizing “red flag” symptoms is important for a person with lupus. A sudden onset of severe, sharp, or rapidly worsening abdominal pain should prompt immediate medical evaluation. This type of pain, particularly if accompanied by a rigid or board-like abdomen, can signal a serious condition like intestinal ischemia, bowel perforation, or acute peritonitis.
Other warning signs include a persistent high fever and chills, suggesting a severe infection or deep-seated inflammation. The presence of blood in the stool or vomit, or dark, tarry bowel movements, indicates gastrointestinal bleeding that requires emergency care. The inability to pass gas or stool, coupled with severe abdominal distension, may signal a bowel obstruction. When seeking emergency care, clearly communicate a lupus diagnosis and provide a complete list of current medications.