Colic - General Concepts

Simple Obstruction

When the lumen is blocked by a foreign body preventing movement of ingesta (usually occurs in large intestine)

Obstruction → decreased absorption of fluid proximal to site → acid/base imabalance → eventual hypovolemia → gas and SI secretions accumulate proximal to site

Sequella of simple obstruction in SI

Rapid in SI, slower onset in small colon

How fast is deterioriation in simple obstruction of SI? Small colon?

Strangulating Obstruction

Both a physical blockage of the lumen and occlusion of mesenteric blood supply

Obstruction → blood engorgement of walls → collapse of capillaries → occlusion of arterioles and tissue hypoxia → cessation of blood flow → intestinal wall necrosis → absorption of bacterial endotoxin → endotoxemia → endotoxic shock

Mechanism of strangulating obstruction