Bowel Obstruction
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| 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.
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| 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
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| 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
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| 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.
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| what are the causes of persistent pain in SBO? (2) | 1. severe bowel distension --> venous congestion, dec perfusion, necrosis), 2. strangulation --> ischemia
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| what is the most vital aspect of treatment in SBO? | restore intravascular volume --> maintain organ perfusion (esp before general anesthesia)
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| 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
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| Ileus | distension of small bowell and/or colon from nonobstructive causes (inflammation, infection, recent surg, meds)
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| 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
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| likely causes of SBO in child (6) | 1. hernia, 2 . Malrotation, 3. meconium ileus, 4. Meckel diverticulum, 5. intussusception, 6. intestinal atresia
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| likely causes of SBO in adult (5) | 1. adhesions, 2. hernia, 3. Crohn dz, 4. gallstone ileus, 5. tumor
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| Extraluminal causes of bowel obstruction (5) | adhesions (75% of all bowel obstruction), hernias, carcinomas, abscesses (ie. s/p appendicitis), and volvulus
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| % of re-operation for adhesion lysis with symptomatic bowel obstruction | 5-15% of abdominal surgery
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| 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)
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| Intraluminal causes of bowel obstruction (5) | gallstones, enteroliths or meconium, foreign bodies, intussusception, or bezoars (hairballs)
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| 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
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| 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
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| tx for complicated SBO | surgery
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| T/F Presence of BM effectively rules out bowel obstruction | FALSE
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| In pt w frequent emesis, what acid/base abnlity is seen? | Metabolic alkalosis
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| If pt has ischemic bowel, what acid/base disorder will they get? | metabolic lactic acidosis
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| 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
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| 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
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| 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.
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| Why low grade fever and tachycardia in bowel obstruction pt? | dehydration and inflammation - will show leukocytosis w L shift
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| 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
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| 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
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| 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
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| 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
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| 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
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| 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
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| 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
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| 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)
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| what is the danger of decreased intravascular volume in SBO pt? | risk of hypoperfusion and remote organ dysfxn
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| What is the difference in sx's of pt with proximal vs. distal SBO? | proximal - more frequent vomiting; distal - more distension
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| In pt with SBO, what does feculent vomitus suggest? | long-standing distal SBO with bacterial overgrowth
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| KUB showing dilated small bowel +/- colonic air | SBO OR ileus
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| what can you see on CT of SBO pt that is diagnostic for mechanical obstruction? | transition from dilated to decompressed bowel
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| What studies besides KUB can you use to diagnose SBO? | upper GI with small bowel follow through AND CT scanning
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| 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.
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| 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
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| for pts with uncomplicated partial SBO treated nonoperatively, when shld pts demonstrate improvement? | 6 to 24h after initiation of tx
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| 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
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| 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
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| What is surgical tx for SBO? | ID and removal of obstruction, lysis of adhesions, resect ischemic or necrotic bowel
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| 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
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| 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
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| 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
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| when is it appropriate to tx SBO nonoperatively | partial SBO
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