Intestinal Obstruction Flashcards
2 causes of intestinal obstruction
- dynamic
2. Adynamic
mechanical blockage of normal propulsion and passage of intestinal contents
Dynamic obstruction
Intestines fail to transmit peristalsis due to failure of neuromuscular mechanism
Adynamic obstruction
3 causes of dynamic obstruction
- Intraluminal
- Intramural
- Extramural
2 causes of adynamic obstruction
- Paralytic ileus
2. Pseudo obstruction
4 causes of intraluminal obstruction
- Faecal impaction
- Foreign bodies
- Bezoars
- Gallstones
4 causes of intramural obstruction
- Stricture
- Malignancy
- Intussuception
- Volvulus
2 causes of extramural obstruction
- Bands/adhesions
2. Hernia
Classification of intestinal obstruction
- Acute/Chronic (duration)
- Partial/ Complete (extent)
- Small bowel/large bowel (sites)
Causes of complete obstruction
- Simple
- Closed loop obstruction
- Strangulation
What causes a closed loop obstruction
There is a carcinomatous stricture at hepatic flexure and ileocaecal valve is competent causing pressure increases in the caecum
This causes stercoral ulcer in caecum leading to gangrene and perforation - peritonitis
Perfoation also occurs due to malignant growth
3 causes of strangulation
- Direct pressure of the bowel wall (hernia, adhesions)
- Interrupted blood flow (volvulus, intussusception)
- Increased intraluminal pressure (closed-loop obstruction)
Systemic effects of obstruction
. Water and electrolytes loss • Toxic materials and toxemia • Cardiopulmonary dysfunction • Renal failure • Shock and death
Symptoms of obstruction
- Abdominal pain (sudden in acute intestinal perforation)
- Nausea and vomiting (early in proximal SBO)
- Abdominal distention (early in distal BO)
- Obstipation (no flatus or stool )
Significant vitals in obstruction
Tachycardia
Orthostatic hypotension
Significant general examination in obstruction
Dehydration (SBO)
Significant abdominal inspection findings
- Abdominal Distension
- Surgical Scars
- Overlying skin changes on the mass if present
Significant palpation findings
- Hernia
- Abnormal mass
- Tenderness
- Rigidity
- Guarding
Significant percussion findings
- Hyperresonance or tympany throughout abdomen
- Tenderness to percussion- peritonitis
- If tympany over liver instead of dull – free intraabdominal air
Significant auscultation findings
- Bowel sound high pitched initially
- Muffled
- Hypoactive with progression of obstruction
Significant DRE findings
- Fecal impaction/rectal mass
2. Gross/occult blood- intestinal tumor, ischemia, intussusception
Significant investigations to be carried out
- Complete blood count with differentials ( white cell count > 40,000)
- Electrolytes, including BUN and Creatinine
For patients with systemic signs:
• ABG (metabolic acidosis)
• Serum lactate
• Blood culture
Causes of pseudo obstruction / ogilivie syndrome
- Infection
- Surgery
- Drugs
- Mutation in FLNA or ACTG2 gene
Cause of gallstone ileus
Repeated cholecystitis, cholecystoenteric fistula
Difference between children and adult intersucception
Children - most comon, idiopathic, cinical symptos present, non-operative have to do a barium hydrostatic reduction
In adult surgical resection always required
Most common causes of adhesions
- Open surgery
- Dirty surgery
- Perforated appendix
Dirt surgery
an incision undertaken during an operation in which the viscera are perforated or when acute inflammation with pus is encountered during the operation (for example, emergency surgery for faecal peritonitis), and for traumatic wounds where treatment is delayed, and there is faecal contamination or devitalised tissue present”
What are the changes that occur proximal to bowel obstruction
There is an increased peristalsis which then become vigorous.
If the obstruction is not relieved peristalsis ceases causing flaccid, paralysed and dilated bowel.
What are the causes of intestinal changes proximal to obstruction
1.Gas: (Nitrogen- 90%, Hydrogen sulphide)
2.Fluid
Digestive juices (all in ml/24 hrs) Saliva -500
Bile- 500
Pancreatic secretions -500 Gastric secretions -1000
What are the changes that occur at the site of obstruction
Initially the venous return is impaired —> congestion and edema of bowel
Later arterial supply is jeopardized —> loss of shineness, blackish discoloration and loss of peristalsis —> gangrene —> perforation—> bacteria and toxin migration causing peritonitis
Imaging investigations for obstruction
Xray. - Abdominal Supine and Abdominal Erect
CT Scan - with radioiodine contrast and oral contrast
• With water soluble contrast (Adhesive obstruction)
• USG • MRI
What to observe in Xray of abdomen
- Gas fluid levels - The air rises above the fluid and there is a flat surface at the “air-fluid” interface.
- Dilated bowel loops
Difference between small and large bowel obstruction
• Small Bowel Obstruction
- Central distention (GAS)
- Valvulae conniventes
- “Ladder-like dilatation”
- Small diameter
• Large Bowel Obstruction
- Peripheral distention “Picture frame”
- More gross distention
- Haustral indentation & large diameter
When is oral contrast given for imaging
for low grade or intermittent small bowel obstruction
Predictors of strangulation
- decreased bowel wall enhancement
- leukocytosis
- peritoneal signs
- inc serum lactate.
Management for intestinal obstruction
- Supportive Management
- Nasogastric decompression with Ryles tube for free drainages
- Nothing per mouth
- Foley’s catheterization
- Intravenous fluid replacement
- Normal saline
- Hartmann’s solution
- Antibiotics- Broad-spectrum - Mandatory for patients going into surgery
When is non- operative management contraindicated
➢ Suspected ischemia
➢ Perforation
➢ Closed loop obstruction
➢ Strangulated hernia
Non operative management for obstruction
- NG decompression
- IV fluids
- Urinary catheter
- Water soluble contrast agent
Management’s for complete obstruction without ischemia
Resuscitate patient before surgery
Management for adhesive obstruction
Conservative management till 72 hours (chance of spontaneous resolution)
Water soluble contrast agent
Surgical management for obstruction
Midline laparotomy
- Operative Decompression
- Division of adhesions (Enterolysis)
- Resection and Anastomosis
- Bypass
- Stomas (patient unstable)
Difference between viable vs non-viable intestine
Circulation - dark becomes lighter in viable
Shiny vs dull appearance
Firm va flabby, thin and friable
Peristalsis vs no peristalsis
