Diarrhea with pneumonia: what to know

Pneumonia mainly affects the lungs, causing symptoms such as cough, fever, chills, chest discomfort, or coughing up phlegm. Some infections can also disturb the digestive system. Viral illnesses such as COVID-19 or influenza may produce both respiratory and bowel symptoms. Diarrhea can also come from contaminated food, another infection, or an antibiotic used for pneumonia; the timing helps a clinician separate these possibilities.

Diarrhea removes fluid and salts while fever and rapid breathing increase fluid loss. That can leave someone weak, dizzy, thirsty, or passing less urine, and dehydration can make recovery harder.

Take frequent small sips of water or an oral rehydration drink. Continue light meals if tolerated, and avoid alcohol and very fatty foods while stools are loose. Follow the pneumonia treatment plan exactly; do not stop a prescribed antibiotic without speaking with the prescriber. Record stool frequency, temperature, breathing changes, urine output, and any blood or mucus. Keep separate towels and wash hands carefully if an infectious cause is possible.

Seek urgent medical help for severe breathlessness, blue or grey lips, new confusion, fainting, inability to keep fluids down, very little urine, severe abdominal pain, black or bloody stools, or rapidly worsening weakness. Contact a clinician promptly if diarrhea is frequent, begins after antibiotics, or continues while pneumonia symptoms are not improving. A clinician may need to check oxygen, hydration, medicines, and the cause of both problems.

Could the diarrhea be linked to my infection or medicine? How should I replace fluids and salts? Which changes in breathing or urine should prompt urgent help? Do I need testing or a review of my pneumonia treatment?