Health Conditions that Cause Mucus in Stool. A sudden onset of mucus in the stool, accompanied by urgent diarrhea, cramping, fever, and blood in the stool may be indicative of a bacterial infection. If you are having any of these symptoms, contact your physician immediately.
Atelectasis, or localized obstruction of the lungs that may result from mucus plug obstruction, can occur resulting to the collapse of a portion of the lungs. This is enumerated by the study published by Respiratory Care in September 2007.
However, if the body produces too much mucus and it begins to accumulate in the lungs, symptoms can occur. This includes coughing, trouble breathing, fatigue and chest pain or discomfort. In some cases, mucus is an early warning sign of a serious underlying disease.