Enteritis toxin accumulation. Ischemic enteritis is uncommon compared to ischemic colitis due to the highly vascularised nature of the small intestine, allowing for sufficient blood flow in most situations. It develops due to circulatory shock of mesenteric vessels in the absence of major vessel occlusion, often associated with an underlying condition such as hypertension, arrhythmia or diabetes. Thus it has been considered to be associated with atherosclerosis. Surgical treatment is usually required due to the likelihood of stenosis or complete occlusion of the small intestine. Ischemic damage can range from mucosal infarction, which is limited only to the mucosa; mural infarction
Inflammation Sydenham and Virchow. Redness and heat are due to increased blood flow at body core temperature to the inflamed site; swelling is caused by accumulation of fluid; pain is due to the release of chemicals such as bradykinin and histamine that stimulate nerve endings. Loss of function has multiple causes. Acute inflammation of the lung (usually caused in response to pneumonia) does not cause pain unless the inflammation involves the parietal pleura, which does have pain-sensitive nerve endings. The process of acute inflammation is initiated by resident immune cells already present in the involved tissue, mainly resident macrophages, dendritic cells,