The illness caused by the SARS-CoV-2 virus, COVID-19, is most often recognized for its impact on the respiratory system, leading to symptoms like cough, fever, and shortness of breath. However, the virus is systemic, meaning it can affect various organ systems throughout the body, including the gastrointestinal (GI) tract.
Digestive issues are a recognized part of the overall disease presentation for many patients. Abdominal pain is a symptom that can accompany the infection, prompting the need to understand how the virus affects the digestive organs. This article explores how frequently abdominal pain occurs with COVID-19, the biological mechanisms that cause it, and how to distinguish it from other causes of stomach discomfort.
Clinical Presentation and Frequency
While respiratory symptoms remain the most common features of COVID-19, a significant portion of patients experience gastrointestinal distress. GI symptoms, such as nausea, vomiting, and diarrhea, are reported more frequently than abdominal pain, which is a less common manifestation. Studies indicate that abdominal pain is present in a smaller subset of patients, often ranging from 2 to 10 percent of those diagnosed with COVID-19.
Among hospitalized patients, the frequency of abdominal pain can be higher, sometimes reaching nearly 20 percent of cases. The pain is often described as non-specific cramping, frequently associated with diarrhea. In some instances, the pain can be localized, such as discomfort in the upper right abdomen, which may signal inflammation of the liver or related structures. Importantly, these GI symptoms can occasionally be the first or even the only sign of the SARS-CoV-2 infection, appearing before classic respiratory issues.
Mechanisms of Gastrointestinal Involvement
The biological reason SARS-CoV-2 can cause abdominal pain relates to its mechanism for entering human cells. The virus utilizes a specific protein on the surface of human cells called Angiotensin-Converting Enzyme 2 (ACE2) as its entry receptor. While ACE2 is present in the lungs, it is also highly expressed in the lining of the digestive system, particularly on the enterocytes, the absorptive cells of the small intestine.
The high concentration of ACE2 receptors in the gut allows the virus to directly infect and replicate within the intestinal cells. This process is often facilitated by the enzyme TMPRSS2, which helps prepare the virus for entry. Direct viral damage to the gut lining, combined with the body’s localized inflammatory response, is the primary cause of gastrointestinal symptoms, including pain and diarrhea.
The presence of the virus in the GI tract is confirmed by detecting SARS-CoV-2 genetic material in the stool. The resulting inflammation is not limited to the intestines; the systemic immune reaction can also affect nearby organs like the liver, leading to inflammation that presents as abdominal discomfort, often felt in the upper right quadrant. This explains why the illness can manifest with symptoms far beyond the respiratory tract.
Differentiating Abdominal Pain Causes
For individuals experiencing abdominal pain during a possible COVID-19 infection, understanding when to manage symptoms at home and when to seek medical care is a practical concern. Mild abdominal discomfort, especially when associated with nausea or diarrhea, can often be managed with supportive care. This home management includes prioritizing rest, maintaining hydration by sipping clear fluids, and consuming a bland diet to minimize digestive irritation.
It is important to recognize that abdominal pain can signal conditions unrelated to COVID-19 or complications that require immediate attention. Severe, worsening, or highly localized abdominal pain is a serious “red flag” symptom that should prompt an urgent medical evaluation. Other danger signs include persistent vomiting or diarrhea that prevents keeping fluids down, which can quickly lead to severe dehydration.
The appearance of blood in the stool or vomit, a high-grade fever, or a noticeably rigid or distended abdomen are also indications for immediate medical attention. These severe symptoms may suggest an acute issue like appendicitis, a gallbladder problem, or intestinal ischemia. Consulting a healthcare provider helps differentiate COVID-related inflammation from other acute causes and ensures appropriate management.