Systemic Lupus Erythematosus (SLE) is a chronic autoimmune condition where the body’s immune system mistakenly attacks its own tissues and organs. This systemic inflammation can affect nearly any part of the body, including the gastrointestinal (GI) tract. The presence of blood in the stool is a symptom that demands immediate medical evaluation regardless of a person’s health history. For someone with SLE, investigation is necessary to determine if the bleeding results from the disease itself, a side effect of medication, or an unrelated issue.
Direct Impact of Lupus on the Digestive System
Active Systemic Lupus Erythematosus can directly cause gastrointestinal bleeding through autoimmune mechanisms. The most significant cause is Lupus Mesenteric Vasculitis (LMV), where the small and medium blood vessels supplying the intestines become inflamed. This inflammation can narrow or block the vessels, restricting blood flow to the bowel tissue and leading to ischemia (lack of oxygen supply).
The lack of blood supply damages the intestinal lining, resulting in ulceration and hemorrhage, which manifests as blood in the stool. LMV is a rare but potentially life-threatening complication of SLE. When the inflammation primarily affects the small intestine, it is called lupus enteritis, which can also lead to severe GI bleeding.
Lupus enteritis and vasculitis cause the bowel wall to thicken, sometimes leading to intestinal pseudo-obstruction or perforation in severe cases. Gastrointestinal bleeding, whether melena (dark, tarry stool) or hematochezia (bright red blood), is a direct consequence of this severe tissue damage. Timely diagnosis, often involving advanced imaging like CT scans, is paramount as these effects require aggressive immunosuppressive therapy to halt the autoimmune attack.
Medication-Related Causes of Bleeding
Gastrointestinal bleeding in a person with SLE is often a side effect of medications used to manage the condition, rather than the disease activity itself. Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), commonly used for joint pain and inflammation, are a frequent source of GI irritation and bleeding. NSAIDs inhibit protective prostaglandins in the stomach lining, making it vulnerable to acid damage.
This mechanism can quickly lead to erosions, gastritis, and peptic ulcers in the stomach or duodenum, which may then bleed. The risk increases with higher doses or prolonged use of NSAIDs. Corticosteroids, such as prednisone, can also contribute to ulcer formation or complicate existing ulcers.
Immunosuppressive drugs like mycophenolate mofetil and azathioprine, used for severe lupus, can cause significant non-specific gastrointestinal distress, including nausea, vomiting, and diarrhea. While they do not typically cause ulcers directly, the general GI upset they induce can lower the threshold for other causes of bleeding. This complex interplay makes pinpointing the exact cause of bleeding a diagnostic challenge.
Common Non-Lupus Causes of Blood in Stool
A person with SLE is just as susceptible to common gastrointestinal issues as the general population. Most instances of blood in the stool, even for those with an autoimmune disease, stem from non-Lupus related causes. The appearance of the blood offers an initial clue about the source of the bleeding within the digestive tract.
Bright red blood typically indicates a source in the lower GI tract, such as the rectum or anus, and is most often attributed to hemorrhoids or anal fissures. Hemorrhoids are swollen veins, and fissures are small tears in the anal lining, both frequently caused by constipation or straining. These conditions are usually benign.
Dark, tarry, and foul-smelling stool, known as melena, usually signals bleeding from the upper GI tract, where the blood has been partially digested. Diverticulosis, the presence of small pouches in the colon wall, is another common cause of significant lower GI bleeding. The possibility of polyps or colorectal cancer must also be considered, emphasizing the need for a definitive diagnosis.
Recognizing Severity and Seeking Care
Any instance of blood in the stool should be reported to a healthcare provider promptly. Certain signs point to a severe, potentially life-threatening event that requires emergency medical attention. These warning signs include passing a large volume of blood, experiencing severe or sudden abdominal pain, and showing signs of shock.
Symptoms such as dizziness, weakness, rapid heart rate, or shortness of breath suggest significant blood loss and may indicate acute anemia. For patients with SLE, this could signal a severe flare of lupus mesenteric vasculitis, which can rapidly progress to bowel perforation or infarction.
To determine the source of the bleeding, a physician typically orders diagnostic procedures. These include an esophagogastroduodenoscopy (EGD) to examine the upper GI tract, or a colonoscopy to examine the lower GI tract. Prompt identification of the bleeding source is necessary to ensure the correct treatment, ranging from simple dietary changes for hemorrhoids to high-dose intravenous corticosteroids for active lupus vasculitis.