When should one be concerned about a systemic infection from a nonenteric pathogen in a patient presenting with diarrhea?
Most enteric pathogens present with a diarrhea-predominant clinical syndrome, although other symptoms (headache, myalgias, fever, and malaise) may also be present. Most of these infections are self-limited and resolve within a few days. Those that can cause more severe illness ( Shigella, STEC, C. difficile ) are usually readily identified by stool studies. Many other nonenteric infectious agents and systemic illnesses can present with diarrhea. Consideration of these potential etiologic factors is indicated when a patient has persistent diarrhea with negative stool studies, or develops symptoms that are not typically seen with infectious diarrhea syndromes (high fever [> 103°], jaundice, cough, altered mental status).