From the Guidelines
Persistent abdominal pain following influenza infection is most likely caused by post-viral inflammation, gastroenteritis, or post-infectious irritable bowel syndrome, as these conditions are commonly associated with the immune response triggered by the influenza virus 1. According to the study published in the Journal of Infection 1, gastrointestinal symptoms such as vomiting and diarrhea are uncommon in adults, but abdominal pain is rare, suggesting that when it does occur, it may be related to the aforementioned conditions. Some key points to consider include:
- Post-viral inflammation can affect the digestive tract even after the primary infection resolves 1
- Gastroenteritis may develop as a complication of influenza, causing stomach pain, nausea, and diarrhea 1
- Post-infectious irritable bowel syndrome can occur, where gut motility and sensitivity remain altered for weeks or months following the viral illness 1 It is essential to note that if abdominal pain persists beyond 1-2 weeks after influenza recovery, becomes severe, or is accompanied by fever, vomiting, or bloody stool, medical evaluation is recommended to rule out more serious complications such as pancreatitis or appendicitis 1. Treatment typically involves rest, adequate hydration, gentle nutrition with easily digestible foods, and possibly antacids or acid reducers like famotidine (20mg twice daily) or omeprazole (20mg once daily) for stomach irritation 1. Additionally, probiotics may help restore gut flora balance disrupted by the infection or antibiotics 1.
From the Research
Causes of Persistent Abdominal Pain Following Influenza Infection
- Eosinophilic enteritis, a rare condition characterized by intestinal eosinophil infiltration, can cause persistent abdominal pain after influenza infection, as seen in a case report of a 29-year-old female patient with massive ascites and diarrhea after an influenza A virus infection 2.
- Respiratory influenza virus infection can induce intestinal immune injury via microbiota-mediated Th17 cell-dependent inflammation, leading to gastroenteritis-like symptoms such as diarrhea and abdominal pain 3.
- Secondary bacterial infections, which can occur after influenza infection, can also cause intestinal disease and abdominal pain 4, 5.
- In some cases, abdominal pain after influenza infection may be related to functional abdominal pain, which can be caused by a variety of factors, including visceral hypersensitivity, bacterial overgrowth, and bowel dysmotility, as well as centrally mediated neurobiological and psychosocial underpinnings 6.
Mechanisms of Abdominal Pain
- The mechanisms by which influenza infections result in enhanced disease, including development of pneumonia and acute respiratory distress, are multifactorial, involving host, viral, and bacterial factors 5.
- Influenza viral infections can cause damage to the respiratory epithelium, facilitating secondary infection with common bacterial pneumopathogens and leading to secondary bacterial pneumonias that can contribute to respiratory distress and abdominal pain 5.
- The alteration of intestinal microbiota can stimulate IL-15 production from intestinal epithelial cells, promoting Th17 cell polarization in the small intestine and leading to intestinal injury and abdominal pain 3.