Intestinal Obstruction

Prepared by Ahmad Zaki and ZurinaSupervisor : Dr Viknes

Outlines

DefinitionClassifications Pathophysiology CausesHow to diagnoseManagementTake home messages

Definition• Intestinal obstruction is a partial or complete blockage

of the bowel that prevents the contents of the intestine from passing through.

Classification

• Mechanical and functional• Partial and complete• Simple and strangulated• Acute and subacute

Obstruction

Proximal

Dilates

Proximal peristalsis will increase to overcome the

obstruction

it will continue to dilates

reduction of peristaltic strength

resulting in flacidity and paralysis

Obstruction

Below/distal

Exhibition normal peristalsis and absorption

Until it become empty

collapses

abdominal pain,

distention, vomiting and

absolute constipation.

Pathophysiology for Mechanical IO

Varieties underlying causes

Systemic generation of endocrine and inflammatory

mediators

Activation of inhibitory spinal

reflex arcs

Failure of transmission of peristaltic wave

Stasis

Accumulation of fluid and gas

Abdominal Distension, vomiting,

absence of bowel sound and absolute

constipation

Pathophysiology for Functional IO

INTRALUMINAL - Faecal impaction- Foreign bodies- Bezoars - Gallstones

INTRAMURAL- Volvulus- Intussusception- Malignancy - Stricture

EXTRAMURAL- Bands / adhesions- Hernia

Causes INTESTINAL

OBTRUCTIONParalytic Ileus

Pseudo- obstructionFUNCTIONAL

MECHANICAL

• ELDERLY – carcinoma, diverticulitis, sigmoid volvulus

• ADULT – hernia, adhesion, carcinoma• PAEDIATRICS – intussusception, congenital

hypertrophic pyloric stenosis, atresia (duodenum, ileum), meconium obstruction, volvulus neonatorum

How to diagnose?

• Thorough history and clinical examination• Investigations– Biochemical test– Radiology

History

4 cardinal symptoms• Abdominal pain• Vomiting and nausea• Abdominal distention • Absolute constipation

Others: dehydrations, hypokalaemia, pyrexia, abdominal tenderness, high pitched bowel sound.

1) Pain• first symptom, occurs suddenly and usually severe. • Nature : colicky, coincide with peristalsis constant,

diffuse as distension increases.• severe pain indicative of strangulation.

2) Vomiting• The more distal the obstruction, the longer interval

between the onset of symptoms and nausea/vomiting.• As obstruction progresses the character of the vomitus

alters (digested food faeculent material; as a result of the presence of enteric bacterial overgrowth)

3) Distension• Small bowel: dependent on the site of the obstruction

and is greater the more distal the lesion.• Colonic obstruction: delayed distension • Visible peristalsis may be present.

4) Constipation• Absolute or relative.

– Absolute constipation COMPLETE intestinal obstruction.• The rule that constipation is present in intestinal

obstruction does not apply in:– Richter’s hernia; gallstone obturation; mesenteric vascular

occlusion; obstruction associated with pelvic abscess; partial obstruction (faecal impaction/colonic neoplasm) ~diarrhoea may often occur.

The clinical features vary according to:• the location of the obstruction• the age of the obstruction• the underlying pathology• the presence or absence of intestinal ischaemia.

■ In high small bowel obstruction, vomiting occurs early and is profuse with rapid dehydration. Distension is minimal ■ In low small bowel obstruction, Vomiting is delayed. pain is predominant with central distension. ■ In large bowel obstruction, distension is early and pronounced. Pain is mild and vomiting and dehydration are late.

Physical examinationInspection• Visible scar -band

-adhesionPalpation• hernial orifices

• large, slightly tender, mobile

• mass changes its position with colicky pain

• tender indurated mass• hard impacted masses

-incarcerated -strangulated hernia- torsion- intussusception-mass of Ascaris worms

- intraperitoneal abscess- fecaloma

Percussion - tympanic sound

Auscultation -runs of borborygmi-tinkling high pitched musical sounds

Rectal examination• fresh blood and mucus

• hard mass of faeces• hard mass in the

rectovesical pouch

-strangulating lesion-carcinoma of large gut-intussusception- constipation-extraintestinal tumour

InvestigationsBiochemical test

• FBC

• BUSE

• Arterial blood gasses• Clotting profile• Optional (ESR, CRP, Hepatitis

profile, tumour markers)

- high Hb and hematocrit- leukocytosis- Anaemia

- electrolytes depletion (hypokalemia, hyponatreamia)

-- acidosis

• X-RAYS -Gas pattern-Fluid level-Masses shadow-Fecal pattern

• ULTRASOUND -free fluid-masses-mucosal folds-pattern of paristalsis

• CT, MRI, Contrast studies -level of obstruction-partial or complete-cause of the obstruction

Radiology

Large Bowel: Small Bowel:

•Peripheral•Presence of haustration, diameter >8 cm•distended caecum a rounded gas shadow in the right iliac fossa. >10cm diameter.

•Central•jejunum valvulae conniventes•Ileum featureless•Diameter >5 cm•No gas is seen in the colon

Multiple air fluid levels located centrally-small bowel obstruction

Small bowel volvulus-coffee bean appearance.

Management• Early management• Conservative• Operative

Early management• Resuscitation– Oxygen therapy (if necessary)– Correct dehydration and electrolytes– IV antibiotics-IV cefobid 1gm bd, IV flagyl 500 mg tds

• Close monitoring– Temperature,Pulse,BP,Urine output, Central venous

pressure• Regular re-evaluation • Keep nil by mouth• Nasogastric tube- 4hourly aspirate and free flow • Appropriate analgesia

Conservative If obstruction presumed to be due to adhesions and there are no features of

peritonism, conservative management may be consider.

– Nasogastric tube • to help decompress the dilated bowel

– CBD• To monitor urine output

– IV fluid• Normal saline or Hartman’s for intravascular volume depletion

– Electrolytes correction• Guided by test results

– Analgesic• Opioid pain relievers may be used for patients with severe pain

– Antibiotic• If bowel ischemia or infarction is suspected

Operative

Principles of surgical intervention for obstruction• Management of:– The segment at the site of obstruction– The distended proximal bowel– The underlying cause of obstruction

Indications for surgery

• Immediate intervention:– Evidence of strangulation (eg:hernia)– 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

Take home messages

• The 4 main Cardical signs of intestinal obstruction are Abdominal pain, Abdominal distention, Vomiting and Constipation.

• Always examine for hernia orifice.• Request for Supine, Erect and CXR.• Provide adequate resusitation to the patient. • Be attentive of signs of peritonitis resulting

from perforation or ischemia of bowel.