Small bowel obstruction cases - Julie Cornish
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Transcript of Small bowel obstruction cases - Julie Cornish
Small bowel obstruction
Case-based teaching module
Case 1 Dear surgeon on-call,
Please see this 72 year old lady whom I visited at home today. She complains of abdominal pain and vomiting. BNO
o/e dryAbdo distended ++
Many thanks, GP
Objectives
• Describe and classify the common causes of small bowel obstruction
• Understand initial resuscitation• Appreciate the role of different investigations• Understand the principles of operative and
non-operative management
Small bowel obstruction - history
What key features will you seek in the history?• Site of pain• Nature of pain• Duration of pain• Duration of vomiting – bilious vs “faeculent”• When bowels last open, passing flatus• Recent history suggestive of malignancy• PMH – abdominal surgery - intra-abdominal pathology eg. Crohns
Why does small bowel obstruction tend to cause central colicky pain?
• Small bowel is of midgut embryological origin
• What are the anatomical borders of the foregut, midgut and hindgut derivatives?
Foregut
• (Pharynx)• Oesophagus• Stomach• Duodenum (D1 & ½ D2)• Liver, Pancreas, Biliary tree
• Blood supply?
Coeliac trunk
Midgut• Duodenum from ½ D2 onward• Jejunum• Ileum• Caecum• Ascending colon• Prox ⅔ Transverse Colon
• Blood supply?
SMA
Can you Label branches?
Midgut Arterial Supply
SMA
Middle Colic
Right Colic
ileocolic
Jejunal branches
Ileal branches
Appendicular
Inferior pancraetoduodenal
Hindgut
• Distal ⅓ Trasverse Colon•Descending Colon•Sigmoid Colon•Rectum
• Blood supply?
IMA
Label branches?
Hindgut
Superior rectal
IMA
Left colic
Sigmoid branches
Case 1 - history• 2 day history• Colicky central abdo pain• Vomiting last 24hrs, bilious• Bowels open 2 days ago, not passing wind• No recent weight loss/change in bowel habit/anaemia
• PMH – “bowel resection” for Crohn’s disease 20 years ago. No follow up since
- admission 2001 with adhesions, conservative - type 2 diabetes, insulin requiring
Small bowel obstruction - examination
What are you particularly seeking and trying to assess with examination?
• Hydration status of patient Mucous membranes, observations
• Signs of small bowel obstruction Abdominal distension Tinkling bowel sounds
• Potential causes of small bowel obstruction Abdominal scars Hernia Abdominal mass
• Evidence of small bowel strangulation/ischaemia or perforation Peritonism Fever
Case 1 - examinationo/e• Dry mucous membranes• Bilious vomitus on gown• HR 100, BP 130/70, T 36.9• Distended abdomen• Bowel sounds tinkling• Generally tender, no guarding• Midline laparatomy scar, no incisional hernia• No masses• Groin hernial orifices normal• PR – empty rectum
Small bowel obstruction - investigations
What initial investigations would you request and why?• Bloods FBC - ↑WCC suggests ischaemia, ↓Hb and MCV could suggest tumour U+Es – assess electrolyte loss, acute renal impairment LFTs Amylase – pancreatitis with ileus could present similarily
• AXR – seek bowel dilatation, sensitivity 60-80%• Erect CXR – seek perforation, sensitivity 80%• ABG – metabolic status of patient, evidence of
intestinal ischaemia
Biochemical markers of bowel ischaemia
• Metabolic acidosis is a late change• An isolated elevated lactate can be misleading• Persistent elevated lactate despite rehydration
suggests ischaemia
Case 1 - investigations
• WCC 7• HB 12 MCV 85• U 15 Cr 150 K 3.1 Na 134• Amylase 121
Case 1 - investigationsComment on the findings
Case 1 - AXR
•Multiple loops small bowel•Centrally positioned•Prominent valvulae coniventes•Cannot see rectum
How sensitive is AXR at detecting SBO?
~ 80%
Case 1 – initial management
• What are your priorities?• Rehydration/Resuscitation• Monitor UO + response to - catheter• Decompression – NG tube• Analgesia• DVT/PE prophylaxis
What measures would you use to guide your fluid and electrolyte administration?
• Estimation of fluid loss, likely to be litres of electrolyte-rich fluid in small bowel or lost already in vomit
• Estimation of daily requirements based on weight
• Estimation of ongoing losses, NG output• Urine output• U + Es
Case 1
• You have commenced iv fluid and electrolyte rehydration, with NG decompression and UO monitoring.
• You now need to decide on potential differential diagnoses and definitive management
What are the commonest causes for small bowel obstruction?
• Adhesions• Malignancy (including primary and metastatic
deposits)• Hernia(commonest cause in developing world)
How would you classify causes of SBO?
• Intra-luminal
• Luminal
• Extra-luminal
Intra-luminal
• Gallstone• Foreign body• Parasites
Luminal
• Tumour Primary – Small bowel eg. Lymphoma - Caecal tumour Secondary
• Inflammatory Crohn’s Radiation Post-op stricture
• Intussusception
Extra-luminal
• Adhesions Congenital Acquired
• Hernia
What are the likely differential diagnoses for our patient?
• Adhesions – laparotomy and “bowel resection” for Crohn’s disease 20 years ago
• Crohn’s stricture - seems unlikely given disease has not been active
• Should bear in mind other diagnoses, particularly malignancy, given patient’s age
Case 1 - Management
• It is 9pm on Monday, do you think this patient needs surgery tonight? Tomorrow?
What do you think are the indications for urgent surgery in small bowel obstruction?
• Evidence of strangulation – peritonism - leucocytosis• Perforation• Irreducible hernia
Case 1 - management• You decide to continue conservative treatment overnight
and r/v the patient on the WR the following morning• What features would you seek to decide whether
conservative management should be continued? NG output Peritonism Temperature HR Change in pain Flatus?
Small bowel obstruction – further investigations
• Water-soluble contrast studyo Useful in identifying patients with SBO that
are unlikely to settle with conservative Rxo Failure of contrast to reach caecum by 4 hrs
indicates surgical intervention likely to be necessary.
o Therapeutic in adhesional SBO due to osmolar effect
Gastrografin therapy for adhesional SBO
• 40 patients suspected adhesional SBO• Randomised to conventional treatment or
gastrografin• Water soluble contrast reduced hospital stay,
mean difference = –2.58; p = 0.004• Did not reduce need for surgical intervention
Burge J, Abbas SM, Roadley G et al. Randomized controlled trial of Gastrografin in adhesive small bowel obstruction. ANZ J Surg 2005; 75, 672-674.
Small bowel obstruction – further investigations
• CTo Gives information on other organs/pathology
outside the bowelo Oral contrast can have similar therapeutic
effecto Disadvantage is cost and radiation exposure
CT for small bowel obstruction
• Break out session for requesting CT from radiologist
Case 1 - CT
Laparotomy for small bowel obstruction
Describe your approach?• Midline incision• Identify transition point (Examine small bowel from DJ
flexure to IC valve)• If entire small bowel dilated with no transition point,
diagnosis of mechanical obstruction may be incorrect• Decompress small bowel by milking and aspirating
through NG tube• Take care not to tear friable distended bowel• Cover dilated bowel loops with moist packs
Laparotomy for small bowel obstruction
• When point of obstruction identified, treat cause– Divide adhesions/congenital bands– Right hemicolectomy for obstructing caecal tumour– Resect Crohn’s stricture
• Inspect any bowel caught in band/hernia for viability
• Resect ischaemic bowel and consider anastamosis vs exteriorisation
Laparotomy for Small bowel obstruction
Small bowel obstructionHow would your management differ in this 79 yr old lady with a similar history?
Small bowel obstructionSBO likely due to incarcerated inguinal/femoral hernia
Small bowel obstructionAnd this patient?