| Question |
Answer |
| 43y m w h/o abd lap, now 16h of int crampy abd pain & bilious vom. Sx's began 3h p lunch & bttr w vomiting, but ret 1-2h ltr. 1BM at onset. No flatus/stool since. Feb, tachy, inc BP, tachypnea, dist & tender abd, hypoBS, hi-pitch. |
mechanical SBO. also have Leuko w L shft, inc amylase. xray w dilated bowel & air-fluid levels. |
| If pt has s/s of high grade mechanical SBO, what is next step in management? |
NG tube to decompress stomach, IVF, Foley to monitor urine output to assess response to fluid resuscitation |
| complications of SBO (5) |
1. strangulation, 2. bowel necrosis, 3. sepsis, 4. aspiration pneumonitis (if vomiting), 5. intravascular fluid loss (third-spacing and vomiting) --> prerenal azotemia and acute renal insuff |
| tx for mechanical SBO (6) |
CT scan, NPO, NG tube, IVF, foley to monitor fluid status. Then abx if signs of inflammation or going to OR. Exploratory laparotomy if nonresponsive to nonoperative tx or if severe at presentation. |
| what are the causes of persistent pain in SBO? (2) |
1. severe bowel distension --> venous congestion, dec perfusion, necrosis), 2. strangulation --> ischemia |
| what is the most vital aspect of treatment in SBO? |
restore intravascular volume --> maintain organ perfusion (esp before general anesthesia) |
| Closed loop SBO. What is it and what is treatment? |
blockage at both proximal and distal end of bowel (ie bowel incarcerated in hernia, intestinal volvulus), more rapid progression to strangulation, unlikely to resolve without surgery |
| Ileus |
distension of small bowell and/or colon from nonobstructive causes (inflammation, infection, recent surg, meds) |
| gallstone ileus |
mechanical obstruction of small bowel due to large gallstone; stone in gallbladder enters adjacent duodenum --> intermittent bowel obstruction for several days until the stone lodges in the distal small bowel --> complete obstruction, constant |
| likely causes of SBO in child (6) |
1. hernia, 2 . Malrotation, 3. meconium ileus, 4. Meckel diverticulum, 5. intussusception, 6. intestinal atresia |
| likely causes of SBO in adult (5) |
1. adhesions, 2. hernia, 3. Crohn dz, 4. gallstone ileus, 5. tumor |
| Extraluminal causes of bowel obstruction (5) |
adhesions (75% of all bowel obstruction), hernias, carcinomas, abscesses (ie. s/p appendicitis), and volvulus |
| % of re-operation for adhesion lysis with symptomatic bowel obstruction |
5-15% of abdominal surgery |
| intrinsic bowl wall causes of bowel obstruction |
most likely is cancer/tumor, more rare are inflammatory or radiation strictures and congenital abnormalities (duplication, atresia, stenosis) |
| Intraluminal causes of bowel obstruction (5) |
gallstones, enteroliths or meconium, foreign bodies, intussusception, or bezoars (hairballs) |
| sx's for SBO (5) |
1. cramplike abd pain, 2. nausea, 3. bil vom -> all because obstr blocks intestinal cont; 4. BM at onset -> because of stim of peristalsis leading to evacuation of the distal GI contents; 5. abd exam with mild, diffuse tenderness, 6. labs - leuk w L shift |
| sx's for complicated SBO (6) |
1. persistent pain, 2. fever, 3. tachycardia, 4. leukocytosis, 5. elevated serum amylase, 6. radiographic signs of high-grade SBO |
| tx for complicated SBO |
surgery |
| T/F Presence of BM effectively rules out bowel obstruction |
FALSE |
| In pt w frequent emesis, what acid/base abnlity is seen? |
Metabolic alkalosis |
| If pt has ischemic bowel, what acid/base disorder will they get? |
metabolic lactic acidosis |
| initial w/u for pts with suspected bowel obstruction (3) |
1. labs (CBC with diff, chem7, amylase and lactate - both may be elevated in SBO), 2. UA, 3. KUB (dilated small bowel +/- colonic air), 4. ABG |
| If initial w/u (inc KUB) is suspicious for SBO, what is next step? (3) |
1. If incarcerated hernia --> surg, 2. if h/o abd surg --> if no complications, then trial of nonoperative management, if complications, then IVF and surg, 3. if no h/o abd surg --> CT scan |
| If initial w/u (inc KUB) is suspicious for large bowel obstruction, what is next step? |
CT scan. If confirms LBO, then treat. If no LBO or SBO, then treat ileus. |
| Why low grade fever and tachycardia in bowel obstruction pt? |
dehydration and inflammation - will show leukocytosis w L shift |
| What should you be thinking if suspected bowel obstruction pt continues to be tachy after restoration of intravascular volume? |
Unresolved inflammation from small bowel ischemia or necrosis |
| What should you be thinking if suspected bowel obstruction pt continues to have leukocytosis after restoration of intravascular volume? |
suspicion of complicated SBO, may need early surgical intervention |
| What should you be thinking if fever in pt with suspected bowel obstruction? (2) |
bowel ischemia and/or pulm complications due to aspiration of gastric contents |
| Pt suspected of SBO with non-specific tenderness on abd exam that does not improve after decompression by placement of NG tube |
Can still be SBO; uncomplicated SBO may show improvement with NG tube decompression |
| What should you consider if pt suspected of bowel obstruction has localized tenderness? |
severe distension or bowel ischemia, this pain is not specific for ischemia |
| What would you expect on DRE of pt with bowel obstruction? |
DRE often reveals little or no stool in rectal vault because of continued peristalsis and evacuation of stool from distal bowel |
| What would you think if DRE of suspected SBO pt revealed large amt of stool in the rectum? |
suggests ileus rather than SBO as cause of distension |
| why do pts with SBO lose intravascular volume? (4) |
1. reduced absorp -> fluid acc in bowel (edema -> dec absorp), 2. local inflam & ven conges -> fluid shift, 3. trans fluid loss into periton, 4. vomiting (sterile bowel contents overgrown w bacteria->emesis, met alk (hypoCl, hypoK), & worse hypovol) |
| what is the danger of decreased intravascular volume in SBO pt? |
risk of hypoperfusion and remote organ dysfxn |
| What is the difference in sx's of pt with proximal vs. distal SBO? |
proximal - more frequent vomiting; distal - more distension |
| In pt with SBO, what does feculent vomitus suggest? |
long-standing distal SBO with bacterial overgrowth |
| KUB showing dilated small bowel +/- colonic air |
SBO OR ileus |
| what can you see on CT of SBO pt that is diagnostic for mechanical obstruction? |
transition from dilated to decompressed bowel |
| What studies besides KUB can you use to diagnose SBO? |
upper GI with small bowel follow through AND CT scanning |
| What to do if pt develops SBO within 30 d of abdominal operation? What is the cause? |
narrowing of lumen or ileus --> nonoperative observation. CT scan to r/o infxn. |
| initial tx for pts with uncomplicated partial SBO from adhesions (4) |
trial of nonoperative therapy: 1. NPO, 2. NG tube, 3. IVF, 4. follow w exam, labs, imaging |
| for pts with uncomplicated partial SBO treated nonoperatively, when shld pts demonstrate improvement? |
6 to 24h after initiation of tx |
| How can you tell that a pt with uncomplicated SBO is responding to nonoperative tx? (3) |
1. dec in abd discomfort and distension, 2. dec in volume of NG aspirate, 3. radiographic resolution of bowel distension |
| What should you do if pt with uncomplicated SBO is not responding to nonoperative tx? |
CT scan or UGI/SBFT to confirm dx or further define obstruction for surg |
| What is surgical tx for SBO? |
ID and removal of obstruction, lysis of adhesions, resect ischemic or necrotic bowel |
| What are you looking for on CT in pt with suspected SBO? |
Obstruction (mechanical vs. ileus; quantify degree of obstruction), possible malignancy, gallstone ileus, internal hernia |
| If SBO pt has anion gap acidosis, what does it mean and what should you do? |
probably ischemia or severe fluid depletion --> build up of lactic acid; if intra-abd sepsis or high-grade obstruction on CT --> surgery |
| In which SBO pts would you NOT need CT imaging? |
1. pts with simple SBO 2/2 adhesions, 2. absense of indicators of complicated SBO |
| when is it appropriate to tx SBO nonoperatively |
partial SBO |
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