The appearance of bloody stool can be alarming, prompting concerns about its underlying cause. As the COVID-19 pandemic introduced a wide array of symptoms, questions have arisen regarding its potential impact on various bodily systems, including the gastrointestinal tract. While COVID-19 is primarily recognized for its respiratory effects, it can manifest with broader implications. This article offers general information and should not replace professional medical advice.
How COVID-19 Affects the Gut
The SARS-CoV-2 virus, responsible for COVID-19, can interact with the gastrointestinal (GI) system. The virus primarily gains entry into human cells by binding to angiotensin-converting enzyme 2 (ACE2) receptors. These receptors are abundantly present not only in the lungs but also in various parts of the GI tract, including the small intestine and colon.
Once the virus enters the intestinal cells, it can trigger localized inflammation. This inflammation might disrupt the normal function of the gut lining and affect the gut microbiota. Alterations in the gut microbiota composition have been observed in COVID-19 patients.
Beyond direct viral effects on intestinal cells and inflammation, the systemic inflammatory response and hypercoagulable state associated with severe COVID-19 can also influence gut health, potentially leading to issues such as ischemic colitis.
Is Bloody Stool a Direct Symptom of COVID-19?
Bloody stool is generally considered a rare direct symptom of COVID-19. While gastrointestinal symptoms like diarrhea, nausea, vomiting, and abdominal pain are reported in some COVID-19 patients, significant GI bleeding directly caused by the virus is not typical. Studies indicate that GI bleeding occurs in a small percentage of hospitalized COVID-19 patients, estimated to be around 1.5% to 3.0%.
If bloody stool occurs in the context of a COVID-19 infection, it is often due to indirect factors or severe complications rather than a direct viral assault on the intestinal lining causing overt bleeding. For instance, severe illness can exacerbate pre-existing conditions like peptic ulcer disease or stress gastritis. Additionally, medications used to treat COVID-19, such as blood thinners or certain anti-inflammatory drugs, can increase the risk of bleeding.
In some rare instances, severe inflammation, vascular issues, or a hypercoagulable state associated with critical COVID-19 may contribute to gastrointestinal bleeding, including conditions like ischemic colitis. The severity of COVID-19 has been linked to an increased risk of gastrointestinal bleeding, particularly lower GI bleeding.
Common Causes of Bloody Stool
Since bloody stool is rarely a direct symptom of COVID-19, understanding its more common causes is important for proper context. One of the most frequent causes of bright red blood in stool or on toilet paper is hemorrhoids, which are swollen veins in the rectum or anus. These are often associated with straining during bowel movements or constipation. Another common benign cause is anal fissures, small tears in the lining of the anal canal, which can also result from passing hard stools and cause pain during bowel movements.
Beyond these common benign conditions, several other gastrointestinal issues can lead to bloody stool. Inflammatory bowel disease (IBD), which includes Crohn’s disease and ulcerative colitis, causes chronic inflammation in the bowels and can result in bleeding, abdominal pain, and diarrhea.
Diverticulitis, an inflammation of small pouches that can form in the colon, is another cause of bloody stool, often accompanied by abdominal pain and fever. Gastrointestinal infections, sometimes leading to hemorrhagic colitis, can also cause bloody diarrhea. Peptic ulcers in the stomach or small intestine can lead to darker, tarry stools, indicating bleeding higher in the digestive tract.
When to Seek Medical Attention
Experiencing bloody stool, regardless of COVID-19 status, warrants medical evaluation to determine the underlying cause. While some instances may be due to minor issues like hemorrhoids, it can also signal a more serious condition. It is advisable to consult a healthcare professional for any instance of bloody stool.
Certain signs should prompt immediate medical attention. These include large amounts of blood in the stool, black or tarry stools (which may indicate bleeding from higher in the digestive tract), severe abdominal pain, dizziness, or weakness.
Other concerning symptoms that warrant prompt care include a rapid heart rate, signs of shock, persistent changes in bowel habits, or unexplained weight loss accompanying the bleeding. If bloody diarrhea occurs alongside fever, severe abdominal pain, or an inability to eat or drink, medical consultation is also recommended.