Intestinal Obstruction

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Intestinal Obstruction

• Ahmed Badrek-Amoudi FRCS

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The common Scenario
A 50 year old gentleman presents with abdominal
pain, distension and absolute constipation. With
repeated episodes of vomiting. His vital sign
were stable, abdomen distended with diffuse
tenderness but minimal peritonism. Bowel Sounds
are hyperactive. The plain abdominal xray was
taken on admission.
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What are your objectives?

• You should be able to address the following
  questions
• Is this bowel obstruction or ileus?
• Is this a small or large bowel obstruction?
• Is this proximal or distal obstruction?
• What is the cause of this obstruction?
• Is this a complex or simple obstruction?
• How should I start investigating my patient?
• What is the role of other supportive
  investigations?
• What is my immediate/ intermediate treatment
  plan?
• What are the indications for surgery?
• What are the medico-legal and ethical issues that
  I should address?

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Introduction and Definitions

• Accounts for 5 of all acute surgical
  admissions
• Patients are often extremely ill requiring
  prompt
  assessment, resuscitation and intensive monitoring

• Obstruction A mechanical blockage arising from a
  structural abnormality that presents a
  physical barrier to the progression of gut
  contents.
• Ileus is a paralytic or functional variety of
  obstruction

Obstruction is Partial or complete Simple or
strangulated
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Patho-physiology I

• 8L of isotonic fluid received by the small
  intestines (saliva, stomach, duodenum, pancreas
  and hepatobiliary )
• 7L absorbed
• 2L enter the large intestine and 200 ml excreted
  in the faeces
• Air in the bowel results from swallowed air ( O2
  N2) and bacterial fermentation in the colon (
  H2, Methane CO2),
• 600 ml of flatus is released
• Enteric bacteria consist of coliforms, anaerobes
  and strep.faecalis.
• Normal intestinal mucosa has a significant immune
  role

• Distension results from gas and/ or fluid and can
  exert hydrostatic pressure.
• In case of BO Bacterial overgrowth can be rapid
• If mucosal barrier is breached it may result in
  translocation of bacteria and toxins resulting in
  bactaeremia, septaecemia and toxaemia.

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Patho-physiology II

• Obstruction results in
• Initial overcoming of the obstruction by
  increased paristalsis
• Increased intraluminal pressure by fluid and gas
• Vomiting
• sequestration of fluid into the lumen from the
  surrounding circulation
• Lymphatic and venous congestion resulting in
  oedematous tissues
• Factors 3,4,5 result in hypovolaemia and
  electrolyte imbalance
• Further localised anoxia, mucosal depletion
  necrosis and perforation and peritonitis.
• Bacterial over growth with translocation of
  bacteria and its toxins causing bacteraemia and
  septicaemia.

• Decompress with NGT
• Replace lost fluid
• Correct electrolyte abnormalities
• Recognise strangulation and perforation
• Systemic antibiotics.

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Causes- Small Bowel
Extraluminal Mural Luminal
Postoperative adhesions Congenital adhesions Hernia Volvulus Neoplasims lipoma polyps leiyomayoma hematoma lymphoma carcimoid carinoma secondary Tumors Crohns TB Stricture Intussusception Congenital F. Body Bezoars Gall stone Food Particles A. lumbricoides
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Small Bowel Adhesions

• Accounts for 60-70 of All SBO
• Results from peritoneal injury, platelet
  activation and fibrin formation.
• Associated with starch covered gloves,
  intraperitoneal sepsis, haemorrhage and wash with
  irritant solutions iodine and other foreign
  bodies.
• As early as 4 weeks post laparotomy. The majority
  of patients present between 1-5 years
• Colorectal Surgery 25
• Gynaecological 20
• Appendectomy 14
• 70 of patients had a single band
• Patients with complex bands are more likely to be
  readmitted
• Readmission in surgically treated patients is 35

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Hernia

• Accounts for 20 of SBO
• Commonest 1. Femoral hernia
• 2. ID inguinal
• 3. Umbilical
• 4. Others incisional and internal H.
• The site of obstruction is the neck of hernia
• The compromised viscus is with in the sac.
• Ischaemia occurs initially by venous occlusion,
  followed by oedema and arterialc ompromise.
• Attempt to distinguish the difference between
• Incaceration
• Sliding
• Obstruction
• Strangulation is noted by
• Persistent pain
• Discolouration
• Tenderness
• Constitutional symptoms

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Other causes
Gall stone Ileus
Intussusception
IBD
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Large Bowel Obstruction

• Aetiology
• 1. Carcinoma The commonest cause, 18
  of colonic ca. present with
  obstruction
• 2. Benign stricture Due to Diverticular disease,
  Ischemia, Inflammatory bowel disease.
• 3. Volvulus 1. Sigmoid Volvulus
  Results from long redundant,
  faecaly loaded colon with a narrow pedicle
• 2. Caecal
  Volvulus
• 4. Hernia.
• 5. Congenital Hirschusbrung, anal
  stenosis and agenesis

Distinguishing ileus from mechanical obstruction is challenging According to Leplacs law maximum pressure is at the its maximum diameter. Cecum is at the greatest risk of perforation Perforation results in the release of formed feaces with heavy bacterial contamination
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Sigmoid Volvulus
Colonic Obstruction
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Radiological Evaluation

• Normal Scout
• Always request Supine, Erect and CXR
• Gas pattern
• Gastric,
• Colonic and 1-2 small bowel
• Fluid Levels
• Gastric
• 1-2 small bowel
• Check gasses in 4 areas
• Caecal
• Hepatobiliary
• Free gas under diaphragm
• Rectum
• Look for calcification
• Look for soft tissue masses, psoas shadow
• Look for fecal pattern

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The Difference between small and large bowel
obstruction
Small Bowel Large bowel
Central ( diameter 5 cm max) Vulvulae coniventae Ileum may appear tubeless Peripheral ( diameter 8 cm max) Presence of haustration
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Role of CT

• Used with iv contrast, oral and rectal contrast
  (triple contrast).
• Able to demonstrate abnormality in the bowel
  wall, mesentery, mesenteric vessels and
  peritoneum.
• It can define
• the level of obstruction
• The degree of obstruction
• The cause volvulus, hernia, luminal and mural
  causes
• The degree of ischaemia
• Free fluid and gas
• Ensure patient vitally stable with no renal
  failure and no previous alergy to iodine

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Role of barium gastrografin studies

• As follow through, enema
• Limited use in the acute setting
• Gastrografin is used in acute abdomen but is
  diluted
• Useful in recurrent and chronic obstruction
• May able to define the level and mural causes.
• Can be used to distinguish adynamic and
  mechanical obstruction

Barium should not be used in a patient with
peritonitis
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How to initially investigate your patient

• Lab
• CBC (leukocytosis, anaemia, hematocrit,
  platelets)
• Clotting profile
• Arterial blood gasses
• U Crt, Na, K, Amylase, LFT and glucose, LDH
• Group and save (x-match if needed)
• Optional (ESR, CRP, Hepatitis profile
• Radilogical
• Plain xrays
• USS ( free fluid, masses, mucosal folds, pattern
  of paristalsis, Doppler of mesenteric vasulature,
  solid organs)
• Other advanced studies (CT, MRI, Contrast
  studiessenior decision)
• ECG and other investigations for co-morbid factors

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Understanding the clinical findings
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Clinical Findings1. History

• Persistent pain may be a sign of strangulation
• Relative and absolute constipation

The Universal Features Colicky abdominal pain, vomiting, constipation (absolute), abdominal distension. Complete HX ( PMH, PSH, ROS, Medication, FH, SH)
Colonic ? Preexisting change in bowel habit Colicky in the lower abdomin Vomiting is late Distension prominent Cecum ? distended Distal small bowel Pain central and colicky Vomitus is feculunt Distension is severe Visible peristalsis May continue to pass flatus and feacus before absolute constipation High Pain is rapid Vomiting copious and contains bile jejunal content Abdominal distension is limited or localized Rapid dehydration
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Clinical Findings2. Examination
Others Systemic examination If deemed necessary. CNS Vascular Gynaecological muscuoloskeltal Abdominal Abdominal distension and its pattern Hernial orifices Visible peristalsis Cecal distension Tenderness, guarding and rebound Organomegaly Bowel sounds High pitched Absent Rectal examination General Vital signs P, BP, RR, T, Sat dehydration Anaemia, jaundice, LN Assessment of vomitus if possible Full lung and heart examination
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Initial Management in the ER

• Resuscitate
• Air way (O2 60-100)
• Insert 2 lines if necessary
• IVF Crytloids at least 120 ml/h. (determined by
  estimated fluid loss and cardiac function). Add
  K at 1mmmol/kg
• Draw blood for lab investigations
• Inform a senior member in the team.
• NPO.
• Decompress with Naso-gastric tube and secure in
  position
• Insert a urinary catheter (hourly urinary
  measurements) and start a fluid input / output
  chart
• Intravenous antibiotics (no clear evidence)
• If concerns exist about fluid overloading a
  central line should be inserted
• Follow-up lab results and correction of
  electrolyte imbalance
• The patient should be nursed in intermediate care
• Rectal tubes should only be used in Sigmoid
  volvulus.

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Indications for Surgery

• Immediate intervention
• Evidence of strangulation (hernia.etc)
• Signs of peritonitis resulting from perforation
  or ischemia
• In the next 24-48 hours
• Clear indication of no resolution of obstruction
  ( Clinical, radiological).
• Diagnosis is unclear in a virgin abdomen
• Intermediate stage
• The cause has been diagnosed and the patient is
  stabalised

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Legal issues and consent
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Ileus

• Associated with the following conditions
• Postoperative and bowel resection
• Intraperitoneal infection or inflammation
• Ischemia
• Extra-abdominal Chest infection, Myocardia
  infarction
• Endocrine hypothyroidism, diabetes
• Spinal and pelvic fractures
• Retro-peritoneal haematoma
• Metabolic abnormalities
• Hypokalaemia
• Hyponatremia
• Uraemia
• Hypomagnesemia
• Bed ridden
• Drug induced morphine, tricyclic antidepressants

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Is this an ileus or obstruction

• Clinical features
• Is there an under lying cause?
• Is the abdomen distended but tenderness is not
  marked.
• Is the bowel sounds diffusely hypoactive.
• Radiological features
• Is the bowel diffusely distended
• Is there gas in the rectum
• Are further investigasions (CT or Gastrografin
  studies) helpful in showing an obstruction.
• Does the patient improve on conservative measures

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Example of ileus