323 Obstruction Flashcards
Types of intestinal obstruction
mechanical from blockage or functional from intestinal dysmotility
most common causes of intestinal obstruction
postoperative adhesions, carcinomatosis, herniation of the abdominal wall
most common origin of carcinomatosis
ovary, pancreas, stomach or colon
responsible for majority of easly postoperative obstruction
adhesions
Most common causes of acute intestinal obstruction
extrinsic, intrinsic diseases and intraluminal abnormalities
Examples of extrinsic disease
adhesions, hernias, neoplasms, etc
Examples of intrinsic disease
congenital malrotation, atresia, stenosis, duplication, congenital bands; IBD, radiation, TB, traumatic, intussusception, volvulus
Example of luminal abnormalities
bezoars, feces, foreign bodies
Operations that are most likely to create adhesions that can cause bowel obstruction
Open operations of the lower abdomen such as appendectomy and colorectal and gynecologic procedures
commonly affected part of volvulus
sigmoid
True or false. It is rare for adhesions or hernias to obstruct the colon
True.
Responsible for most cases of chronic volvulus
Cancer of ascending colon and rectum
Other names of functional obstruction
ileus and pseudo obstruction
Most common identified form of functional bowel obstruction
ileus that occurs after intraabdominal surgery
Relatively rare where patient have chronic dysmotility due to abnormalities of their autonomic nervous system that may be inherited
Ogilvies syndrome
Primary contributor to intestinal obstruction
swallowed air
How early can epithelial necrosis can be identified in intestinal obstruction
Within 12 hours of obstruction
What is the mechanism of dehydration in intestinal obstruction
loss of normal intestinal absorptive capacity as well as fluid accumulation in the gastric or intestinal wall and intraperitoneally
What type of obstruction does nausea and vomiting occur
high grade distal obstruction
How does intestinal obstruction lead to dyspnea and vascular instability
Intraperitoneal fluid increase the intraabdominal pressure enough to elevate the diaphragm inhibiting respiration and to impede systemic venous return leading to vascular instability
Refers to when the proximal and distal openings of a given bowel segment are both occluded like due to a volvulus or a hernia
closed loop obstruction
Most common precursor for strangulation
closed loop obstruction
True or false. All closed loop obstruction leads to strangulation
False. Not every one
At what diameter is the cecum most likely to perforate
Cecal diameter exceed 10-12 cm
What type of patient will present with close loop obstruction early and warrant early intervention
patient with high grade distal obstruction competent ileocecal valuve and prone to close loop obstructon earlier than those with imcompetent ileocecal valves
Cardinal signs of intestinal obstruction
colicky abdominal pain, abdominal distention, emesis and obstipation
In intestinal obstruction which part will be dilated and which part will be collapse
Proximal to the obstruction there is bowel dilatation and the distal part is collapse
Differentiate distal from proximal intestinal bowel obstruction
distal intestinal bowel obstruction greater distention, more discomfort, delayed feculent emesis when there is bacterial overgrowth; proximal intestinal bowel obstruction present with less abdominal distention but more pronounced vomiting
Bowel sounds of early small bowel obstruction
high pitched, musical, tinkling bowel sounds
Differential bowels sounds of intestinal obstruction versus ileus or pseudo obstruction
in intestinal obstruction there is high pitched tinkling bowel sounds in the beginning before becoming absent or hypoactive while in ileus it is hypoactive or absent bowel sounds right at the beginning
in intestinal obstruction there is high pitched tinkling bowel sounds in the beginning before becoming absent or hypoactive while in ileus it is hypoactive or absent bowel sounds right at the beginning
Typical presentation of patient with colonic volvulus
severe abdominal pain, vomiting, obstipation and asymmetrical abdominal distention and a tympanic mass may be evident
classical findings in intestinal obstruction
staircasing pattern of dilated air and fluid filled small loops more than 2.5 cm in diameter with little or no air seen in the colon
When can small bowel air fluid levels not be obvious on abdominal radiograph of intestinal obstruction
air fluid levels may not be obvious if the ileocecal valve is competent
What is the sensitivity of CT scan in detecting bowel obstruction
About 95%; specificity of 96% and accuracy of more than 95%
CT scan imaging of volvulus
birds beak or c-loop or whorl deformity on CT scan show where the twisting obstruct the lumen in volvulus
Most specific early finding of bowel ischemia
altered bowel wall enhancement
Late CT scan findings of bowel ischemia
mesenteric venous gas, pneumoperitonium and pneumatosis intestinalis
True or false. Barium studies are part in the workup of intestinal obstruction for better visibility
False. Barium studies are contraindicated esp in patients with firm evidence of complete or high grade obstruction as it may develop into barium concretions causing additional source of blockage
May be given to patients with ileus to accelerate gastrointestinal recovery
u opioid receptor antagonist such as alvimopan and mehtylnatrexone
An acetylcholinesterase inhibitor that increase cholinergic activity and stimulate colonic motility in patient with Ogilvie’s
neostigmine
True or false. 60-80% of patients with mechanical bowel obstruction can be managed successfully with conservative measures
True.
Done to decompress the stomach, minimize further distention and improve patient comfort
nasogastric tube suction
Most common site of intestinal obstruction in patients with gallstone
ileum in 60% of patients
How early can postoperative mechanical obstruction occurs
as early as the first 6 weeks of operation
true or false. In postoperative bowel obstruction, the longer it tales for the obstructive symptoms to resolve after hospitalization, the more likely is the patient to require surgical intervention
True.
