Bowel obstruction

SURGERY

Intestinal Obstruction

Dynamic: where peristalsis is working against a mechanical obstruction.

Adynamic:
mechanical element is absent Peristalsis my be absent (paralytic ileus) -May be present in non propulsive form. (mesenteric vascular occlusion or pseudo-obstruction)

Causes of intestinal obstruction:

• Adhesions- 40%Z
• Tumors -15%
• Inflammatory- 15%
• Obstructed hernia-12%
• Intraluminal-10%
• Miscellaneous -8%

Mechanical Obstruction

1. Intraluminal: impacted faeces, foreign bodies, gallstones, Bezoars.
2. Intramural: tumors, inflammatory strictures,
3. Extramural: adhesion, hernias, volvulus, intussusception, tumors

Types of Obstructions

Feature	Acute Obstruction	Chronic Obstruction	Acute on Chronic	Subacute Obstruction
Usual Location	Small bowel	Large bowel
Symptoms	Obstruction w/ Severe colicky central abdominal pain, distension, early vomiting, and constipation	Lower abdominal colic & obstipation followed by distension	Short history of distension & vomiting against background of pain & constipation	Incomplete obstruction

Feature	Simple	Strangulation	Closed Loop Obstruction
Symptoms	Blockage without interfering with vascular supply	Significant impairment of blood supply Most commonly associated with hernia, volvulus, intussusception, mesenteric infarction, adhesions/Bands. Surgical emergency	Bowel is obstructed at both the proximal and distal end

Band adhesion causing a closed-loop obstruction.

Pathophysiology

Proximal to obstruction

• Increased fluid secretion ⇒ abdominal distention
• Accumulation of gas ⇒ abdominal distention
• Increased intraluminal pressure
• Vomiting
• Dehydration
• Dilatation of bowel
• Reflex contraction of smooth muscle ⇒ colicky pain
• Increased peristalsis to overcome obstruction ⇒ increased bowel sounds
• If obstruction not overcome ⇒ bowel atony
• Decreased reabsorption with time and flaccidity to prevent vascular damage from high pressure

Distal to obstruction: nothing is passed & bowel collapse ⇒ constipation

• Colicky abdominal pain

• Vomiting

• Abdominal distension – increases as the condition progresses

• Absolute constipation (Obstipation): absence of flatus and stool

• Proximal small-bowel obstruction:

  • less distention and more rapid onset of vomiting.
  • Bilious vomiting

• Distal small bowel obstruction:

  • central abdominal distention
  • vomiting (feaculent) is a late feature (because the bowel takes time to fill)

• In strangulation:

  • severe constant abdominal pain
  • fever
  • tachycardia
  • tenderness with rigidity/rebound
    • tenderness.
  • shock

General examination

Early stage:

• Normal vitals
• Hyperactive bowel sounds

Late stage:

• Vital signs
• Signs of dehydration –tachycardia, hypotension
• dry mucus membrane, decreased skin turgor, decreased urine output
• Inspection:
  • distension, scars, peristalsis, masses, hernial orifices
  • Dilated loops of bowel may be palpable
• Palpation:
  • tenderness, masses, rigidity
• Percussion:
  • tympanitic abdomen
• Auscultation:
  • high pitched bowel sound associated with peristalsis and cramp pain
  • or silent abdomen

Examine rectum for mass, blood, feces or it may be empty in case of complete obstruction

Investigations

• Full blood count (WBC, Hb, Hct), High WBC (neutrophilia with strangulation)

• Electrolytes ( Hypovolemic hypochloremic hypokalemic alkalosis)

• Hyper kalemia, hyperamylasemia & raised LDH may be associated with stangulation.

• BUN, & creatinine levels: If increased, may indicate decreased volume state (e.g, dehydration).

• Abdominal X-ray, at least 2 images (Supine & Erect)

• Small bowel follow-through

• CT abdomen with contrast (Triple)

• Scopes (OGD/Colonoscopy)

Pneumoperitoneum The 3-6-9 rule is describing the normal bowel calibre:

• small bowel: <3 cm
• large bowel: <6 cm
• appendix: <6 mm
• caecum: <9 cm

Z

Rigler triad in gallstone ileus

• Pneumobilia; air in gallbladder due gallstone ileus // C. deficelle alsoZ
• Small bowel obstruction
• Ectopic gallstone

60 c 30fCC

Loss of apetite + pain in illiac fossa + Anorexia weak cough, due pain? - acute appendicitis?

Management

• Starts ABC
• Supportive measures:
  • Nil By Mouth
  • Intake- output charts
  • IV lines, and rehydration (IV crystalloid with K+)
  • Foley’s catheter
  • NG Tube to aspirate content for ‘decompression’
  • TED stockings, DVT prophylaxis
  • Antibiotics
  • Antiemetics
  • Analgesia
  • Might needs ICU
• Obstruction due to adhesion rarely need surgery

Indication for surgery:

• Virgin abdomen. (No previous surgery)
• failure of conservative management
• tender, irreducible hernia
• strangulation, peritonitis

Surgery:

• Assess bowel viability
• Treat the cause
  • Adhesions…. Adhesiolysis
  • Mass…… Resection
  • Hernia…… Repair
  • Etc.

Sigmoid colon tumour obstruction

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IMAGING

A) Mechanical bowel obstruction

is the interruption of normal passage through the bowel due to a structural barrier (Small or large)

B) Functional bowel obstruction or paralytic ileus

is a temporary disturbance of peristalsis in the absence of mechanical obstruction.

• Bowel obstruction typically manifests with nausea, vomiting, abdominal pain, abdominal distention, and constipation.

Radiological appearances:

Dilatation of bowel loops proximal to the obstruction: 3-6-9 rule :To help guide the identification of bowel dilatation on imaging. Transverse diameter greater than the following indicates dilation: Small bowel > 3 cm Large bowel > 6 cm Cecum > 9 cm

• SBO: Dilated loops are predominantly central.
• LBO : Dilated loops are predominantly peripheral.

 Air-fluid level:

• Visible on upright or decubitus views
• Common criteria for diagnosing SBO 3 air-fluid levels & Air-fluid level diameter > 2.5 cm

#Z Mechanical small bowel obstruction-X-ray abdomen (erect) Multiple air-fluid levels are visible in the mid-abdomen. The opaque appearance of the pelvis is due to fluid-filled loops of small bowel. There is a paucity of gas in the colon, and an air-fluid level is present in the dilated stomach.

bowel obstruction