60-64 IleusandBowelObstruction. Flashcards
What are the types of bowel Obstruction (6)
Mechanical obstruction
Functional obstruction.
Simple obstruction
Strangulation obstruction
Open-loop obstruction
Closed-loop obstructions
Mechanical obstruction definition
Mechanical obstruction.
means that luminal contents cannot pass through the gut tube because the lumen is blocked.
definition of
Functional obstruction.
There are neurogenic or functional obstructions in which luminal contents are prevented from passing because of disturbances in gut motility that prevent coordinated peristalsis from one region of the gut to the next.
simple obstruction definition
the intestinal lumen is partially or completely occluded without compromise of intestinal blood flow.
may be complete, meaning that the lumen is totally occluded
or
incomplete, lumen is narrowed but permitting distal passage of some fluid and air.
Strangulation obstruction.
- def
- ceonsequences
complete/ incomplete obstruction
In strangulation obstruction, blood flow to the obstructed segment is compromised and tissue necrosis and gangrene are imminent.
Strangulation usually implies that the obstruction is complete.
Open-loop obstruction. def
open-loop obstruction occurs when intestinal flow is blocked but proximal decompression is possible through vomiting.
Closed-loop obstructions
- def
- is decompression possible
closed-loop obstruction occurs when inflow to the loop of bowel and outflow from the loop are both blocked. This obstruction permits gas and secretions to accumulate in the loop without a means of decompression, proximally or distally
classification of Intestinal obstruction
Dynamic- Peristalsis against a mechanical obstruction
- intraluminal
- intramural
- Extraluminal
Adynamic – absent or non propulsive peristalsis
Dynamic classification of Bowel Obstruction
Intraluminal
- Foreign bodies, Gallstones,
- Parasites, Enteroliths, Intussuseption
- Swallowed objects
Intramural
- Congenital: Meckels, Atresia, Stenosis,
- Inflammatory: crohns, Diverticulitis, Radiation enteritis
- Traumas: Intramural/Extramural
- Tumors: mg/ benign
Extraluminal
- Adhesions
- Meckels bands
- Hernia
- Volvulus
- External Mass Effect
Adynamic /functional obstruction - absent or non propulsive peristalsis
( func obs has disturbances in gut motility )
- paralytic ileus (neuourigenic)
- Mesenteric Vascular Occlusion
- Pseudo-obstruction
Pathophysiology of Intestinal Obstruction
When a loop of bowel becomes obstructed, intestinal gas and fluid accumulate.
Stasis of luminal content favors bacterial overgrowth!! → alters intestinal fluid transport properties and motility, and causes variations in intestinal perfusion and lymph flow. →
altered flow leads to Changes in hydrostatic and osmotic pressures on the blood and lumen sides of the mucosa. →
pressure changes lead to favor flow of extracellular fluid into the lumen. →
Perfusion is compromised as luminal pressures increase,bacteria invade, and inflammation leads to edema within the bowel wall.
complications of closed-loop obstructions
closed loop obstructinos evolve rapidly compared to open loop
blood supply of the obstructed loop is compromised→ gangrene and perforation → free perforation w/ Peritonitis ( clinically leads to a rigid abdomen)
Toxins from necrotic tissue and bacterial overgrowth are released into the systemic circulation → shock ensures
conplications of open-loop obstructions
dosent evolve as quickly since proximal jeujenum can be decompressed by vomitting
Complications / charaacteristics clinical sx of Proximal obstruction
vomiting →loss of gastric, pancreatic, and biliary secretions, → electrolyte disturbances.
- sx of Elyte disturbance
- dehydration,
- metabolic alkalosis
- hypochloremia -( gastric)
- hypokalemia -(bile)
- hyponatremia -(hypovolemic hyponatremia)
Characteristics Complications of Obstructions of the distal ileum
- speed of progression
- most marked comp
this type of obs leads to slowly progressing distention of the small intestine.
distal jejunal obstruction tend to present with complications resulting from
- Loss of intestinal contents from vomiting, as well as
- distention of Lower abdom seg
- compromise of intestinal wall perfusion.