Bronchitis is a common respiratory infection that causes the bronchial tubes, the airways leading to your lungs, to become inflamed and produce excess mucus. When people experience both respiratory symptoms and diarrhea, it is understandable to question if the two are related. The direct answer is that diarrhea is not considered a typical or primary symptom of simple, acute bronchitis.
Diarrhea is Not a Primary Bronchitis Symptom
Acute bronchitis, often called a chest cold, primarily targets the respiratory system. The defining symptom is a persistent cough, which often produces mucus that can be clear, white, yellow, or green. This inflammation and mucus production also frequently lead to chest soreness, fatigue, and sometimes a low-grade fever or mild body aches.
The infection’s effects are largely confined to the airways, meaning inflammation does not typically extend into the gastrointestinal (GI) tract. Chronic bronchitis, usually caused by smoking, similarly presents with a productive cough and chest discomfort but lacks GI symptoms. Diarrhea occurring directly from bronchitis is considered rare.
Why Diarrhea Still Occurs During Respiratory Infections
While bronchitis itself is centered in the chest, diarrhea can still occur due to several factors related to the overall illness or its treatment. The most frequent reason for co-occurring symptoms is the use of medications taken to manage the respiratory infection. Many antibiotics prescribed when a secondary bacterial infection is suspected can disrupt the delicate balance of bacteria in the gut, leading to antibiotic-associated diarrhea.
This disruption occurs because antibiotics eliminate beneficial bacteria along with harmful ones, allowing other organisms to overgrow. In rare but serious cases, this involves Clostridioides difficile, a bacterium that causes severe diarrhea. Additionally, common over-the-counter pain relievers and fever reducers, specifically Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) like ibuprofen, can sometimes irritate the stomach and intestines, contributing to loose stools.
Another element is that the illness might be caused by a virus affecting both the respiratory and digestive systems. Many viruses that cause acute bronchitis, such as influenza or coronaviruses, are systemic and can cause inflammation in both the lungs and the gut. Diarrhea is more common with these infections, especially in children, indicating a single infection is causing both sets of symptoms.
Finally, the body’s response to a severe respiratory infection can sometimes lead to mild GI upset. Excessive mucus produced in the lungs and sinuses often drains into the throat and is swallowed. This ingested mucus can irritate the stomach lining, potentially leading to nausea or a temporary bout of loose stools.
When to Consult a Doctor
If you experience diarrhea alongside respiratory symptoms, monitor the severity and duration. Seek medical attention if the diarrhea lasts longer than 48 hours without improvement. Persistent diarrhea increases the risk of dehydration, especially with fever, so watch for signs like excessive thirst, dark-colored urine, dizziness, or a dry mouth.
Consult a doctor immediately if the diarrhea is bloody or black, or if it is accompanied by a high fever (102°F or higher). These symptoms can signal a more severe bacterial infection, such as C. difficile, or another complication. If you develop severe chest pain, shortness of breath, or feel very weak, it could indicate a complication like pneumonia requiring prompt evaluation.