COVID-19 is primarily known as a respiratory illness, but the causative virus, SARS-CoV-2, affects multiple organ systems. This systemic nature means symptoms extend far beyond the lungs and upper airways. Many patients experience non-respiratory complaints, including neurological, cardiovascular, and gastrointestinal issues. Among these presentations, abdominal pain has emerged as a symptom increasingly recognized as a potential manifestation of the illness.
Abdominal Pain as a Recognized COVID Symptom
Abdominal pain is a recognized, though less frequent, symptom of COVID-19 compared to classic signs like fever, cough, and fatigue. The prevalence varies widely, ranging from a low of 0.5% in some early studies to nearly 20% in cohorts of hospitalized patients.
The pain is often non-specific, presenting as general abdominal discomfort or cramping, especially when accompanied by diarrhea. Abdominal pain can be the sole presenting symptom in a small subset of patients, sometimes appearing before any respiratory issues. Clinicians must therefore consider COVID-19 in the differential diagnosis for acute abdominal pain, even when traditional respiratory symptoms are absent. For those with severe infection, the pain may be intense enough to mimic an acute surgical condition, requiring careful evaluation.
How COVID-19 Affects the Digestive System
The mechanism for COVID-19-related abdominal pain involves the virus’s ability to directly infect cells within the gastrointestinal tract. SARS-CoV-2 uses the Angiotensin-Converting Enzyme 2 (ACE2) receptor to gain entry into human cells. This receptor is highly expressed on enterocytes, the epithelial cells lining the small intestine, often at higher levels than in the lungs.
Once the virus binds to ACE2, it enters and replicates within the intestinal cells, causing localized injury and inflammation, known as enteritis. This direct viral damage and the subsequent immune response release inflammatory chemicals that irritate the digestive tract, which is the likely source of the pain. The localized inflammation can also disrupt the protective barrier of the gut.
The infection and resulting inflammatory state can also impact the gut-brain axis and the balance of the gut microbiome. Vascular complications, such as micro-clots, have been observed in severe cases, leading to reduced blood flow (ischemia) in the mesenteric blood vessels that supply the intestines. This ischemia causes intense, acute pain. Upper right abdominal pain may also be linked to associated liver inflammation caused by the virus.
Related Gastrointestinal Manifestations
Abdominal pain is frequently accompanied by other digestive disturbances. Loss of appetite (anorexia) is one of the most common gastrointestinal symptoms reported, affecting a significant portion of patients. Diarrhea is also highly prevalent, often occurring in approximately one-third of hospitalized individuals.
Many patients also experience nausea and vomiting, sometimes preceding the onset of respiratory complaints. These symptoms, along with abdominal cramping, may be caused by the same inflammatory processes triggered by the viral invasion of the intestinal lining.
Symptom Management and When to Seek Care
For mild abdominal discomfort associated with COVID-19, home management focuses on supportive care to ease the symptoms. Maintaining adequate hydration is important, especially if the pain is accompanied by vomiting or diarrhea, as fluid loss can rapidly lead to dehydration. Consuming a bland diet of easily digestible foods can help minimize irritation to the gastrointestinal tract during the acute phase of the illness.
Over-the-counter medications, such as antacids, may help with general stomach upset or inflammation, but any pain reliever should be discussed with a healthcare provider. Most COVID-related gastrointestinal symptoms resolve within a few days as the infection clears. However, it is important to differentiate manageable viral discomfort from a medical emergency, as severe abdominal pain can signal a non-COVID-related issue.
Immediate medical attention is necessary if the abdominal pain is sudden, severe, and localized, or if it is accompanied by concerning signs. These warning signs should prompt an immediate call to a healthcare professional:
- Persistent, high fever
- Signs of significant dehydration like dizziness or reduced urination
- Inability to keep liquids down
- The presence of blood in the stool, black or tarry stools
- Persistent vomiting that does not resolve