SBO

Question 1

etiology of SBO with classification?

Answer 1

extrinsic obstruction:
-metastatic cancer
-adhesions (most common cause)
-incarcerated hernia
-volvulus (in elderly)

intrinsic obstruction:
1. intramural obstruction:
-cancer
-diverticulitis
-strictures from IBD, crohns
-intussusception (pediatric)

2.intralumen obstruction:
-gallstone ileus
-foreign body ingestion (in elderly)

Question 2

symptoms of SBO and bowel sounds? with complication and its red flags?

Answer 2

cardinal symptoms: colicky abdomen pain and distention, vomiting, constipation/obstipation, high pitched bowel sounds. in paralytic ileus it’s absent bowel sounds

Can progress into ischemia and necrosis and perforation if left untreated
red flags:
-pain out of proportion (dont give pain killers)
-peritonitis (guarding, rigidity, rebound tenderness)
-hemodynamic instability
-high leukocytosis, metabolic acidosis and high lactate

Question 3

differentiate between SBO and LBO through signs and symptoms?

Answer 3

SBO: vomit occurs early and is bilious and large in volume than in LBO, constipation/ob occurs later in course, abdomen distention is less severe

LBO: vomit occurs later is bilious then becomes fecal vomit, constipation/ob occurs early in onset, abdomen distention is severe

Question 4

initial management in emergency? which labs to order?

Answer 4

keep NPO
two large bore IV cannulas
intubate to prevent aspiration and gastric decompression
foley catheter insertion (aim is 0.5cc per kg per hr)
give IV fluids (421 rule first 10kg x 4, next 10kg x 2, rest of kg x 1)
give anti emetics

CBC (WBC, high Hg due to hemoconcentration), RFT, electrolytes (hypochloremic hypokalemic met alkalosis), coagulation profile, LFT if suspect gallstone

Question 5

which imaging to do and what would you find? how to know if LBO or SBO?

Answer 5

first xray especially if pt is unstable then do CT abdomen

multiple air fluid levels (more than 2)
dilated bowel loops (369 rule, more than 3cm for SB, more than 6cm for LB, more than 9cm for cecum). in CT you will see also transition zone at the site of obstruction

if complications: pneumoperitoneum (air under diaphragm), pneumatosis intestinalis (air in the intestinal wall)

LB has haustra
SB has plica circularis (circles)

Question 6

definitive treatment?

Answer 6

supportive as mentioned before esp if cause is IBD.
if patient fails to improve within few days OR presents with complicated obstruction (leukocytosis, acidosis, high lactate, pain out of proportion, peritonitis) OR has cause that requires surgical intervention

exploratory laparotomy
(hernia reduction, adhesiolysis, tumor resection) (resect ischemic bowel)