++
Gastrointestinal (GI) diseases most often present with one or more of four common classes of symptoms and signs: (1) abdominal or chest pain; (2) altered ingestion of food (eg, resulting from nausea, vomiting, dysphagia [difficulty swallowing], odynophagia [painful swallowing], or anorexia [lack of appetite]); (3) altered bowel movements (ie, diarrhea or constipation); and (4) GI tract bleeding, either occurring without warning or preceded by one or more of the foregoing (Table 13–1). However, not all cases of a particular GI disease present in the same way. For example, peptic ulcer disease, although typically accompanied by abdominal pain, may be painless.
++++
GI disease may be limited to the GI tract (eg, reflux esophagitis, peptic ulcer, diverticular disease), be a manifestation of a systemic disorder (eg, inflammatory bowel disease), or present as a systemic disease resulting from a primary GI pathologic process (eg, vitamin deficiencies resulting from malabsorption). Because different parts of the GI tract are specialized for certain functions, the most prominent causes, consequences, and manifestations of disease differ from one anatomic site to another.
++
Acutely, GI disease can be complicated by dehydration, sepsis, or bleeding or by their consequences, such as shock. Dehydration can occur as a consequence of even subtle alterations in fluid input or outflow because the volume of fluid traversing the GI tract daily is enormous (see later discussion). Sepsis can result from disruption of the barrier function against pathogens in the environment, including bacteria resident in the colon. The tendency for bleeding is a reflection of the tremendous vascularity of the GI tract and the difficulty of applying pressure at the site of bleeding.
++
Chronically, GI disease can be complicated by malnutrition and deficiency states. These occur because many primary GI diseases result in ...