This document discusses various causes and classifications of intestinal obstruction, including intraluminal causes like impaction or foreign bodies, intramural causes like strictures or malignancy, and extramural causes like bands, adhesions or hernias. It describes the pathophysiology of obstruction including proximal bowel dilation and changes in motility and absorption. It also covers specific types like strangulation, closed-loop obstruction, internal hernias, enteric strictures, and bolus obstructions. Clinical features of different types of intestinal obstruction and specific causes like gallstones, bezoars, worms, adhesions, intussusception and volvulus are outlined.

1. INTESTINAL OBSTRUCTION

2. CLASSIFICATION
• Dynamic- acute or a chronic form
• Adynamic

3. CAUSES OF INTESTINAL
OBSTRUCTION
• Intraluminal
• Impaction
• Foreign bodies
• Bezoars
• Gallstones

4. • Intramural
• Stricture
• Malignancy
• Extramural
• Bands/adhesions
• Hernia
• Volvulus
• Intussusception

5. • Paralytic ileus
• Mesenteric vascular occlusion
• Pseudo-obstruction

6. PATHOPHYSIOLOGY
• proximal bowel dilates
• altered motility
• Below the obstruction normal peristalsis and
absorption
• Initially, proximal peristalsis is increased
• not relieved, the bowel begins to dilate

7. • flaccidity and paralysis
• prevent vascular damage
• overgrowth of both aerobic and anaerobic
organisms
• gas production
• nitrogen (90%) and hydrogen sulphide

8. • various digestive juices
• fluid accumulates within the bowel wall
secreted
• absorption from the gut is retarded

9. • Dehydration and electrolyte loss
• reduced oral intake
• defective intestinal absorption
• Vomiting
• sequestration in the bowel lumen

10. STRANGULATION
• venous return is compromised before the arterial
supply
• increase in capillary pressure
• local mural distension
• loss of intravascular fluid and red blood cells
intramurally and extraluminally

11. • Once the arterial supply is impaired
• haemorrhagic infarction
• marked translocation and systemic exposure to
anaerobic organisms with their associated toxins
• morbidity of intraperitoneal strangulation is far
greater than with an external hernia

12. CAUSES OF STRANGULATION
• Hernial
• Adhesions/bands
• Interrupted blood flow
• Volvulus
• Intussusception
• Mesenteric infarction

13. CLINICAL FEATURES OF INTESTINAL
OBSTRUCTION
• Dynamic obstruction
• classic quartet of pain, distension, vomiting
and absolute constipation

14. FEATURES OF OBSTRUCTION
• high small bowel obstruction
• vomiting occurs early and is profuse
• rapid dehydration
• Distension is minimal
• little evidence of fluid levels on abdominal
radiography

15. • low small bowel obstruction
• pain is predominant with central distension
• Vomiting is delayed
• Multiple central fluid levels are seen on
radiography

16. • In large bowel obstruction
• distension is early and pronounced
• Pain is mild
• vomiting and dehydration are late
• The proximal colon and caecum are distended on
abdominal radiography

17. CLINICAL FEATURES OF
STRANGULATION
• Constant pain
• Tenderness with rigidity
• Shock

18. CLOSED-LOOP OBSTRUCTION
• obstructed at both the proximal and distal points
• no early distension of the proximal intestine
• gangrene
• retrograde thrombosis of the mesenteric veins
• malignant stricture of the right colon with a competent
ileocaecal valve
• Unrelieved, this results in necrosis and perforation

21. INTERNAL HERNIA
• a portion of the small intestine becomes
entrapped in one of the retroperitoneal fossae
or in a congenital mesenteric defect
• the foramen of Winslow
• a hole in the mesentery

22. • transverse mesocolon
• broad ligament
• congenital or acquired diaphragmatic hernia
• duodenal retroperitoneal fossae – left paraduodenal
and right duodenojejunal
• caecal/appendiceal retroperitoneal fossae – superior,
inferior and retrocaecal intersigmoid fossa

23. ENTERIC STRICTURES
• tuberculosis
• Crohn’s disease
• Lymphoma
• carcinoma and sarcoma are rare
• subacute or chronic

24. BOLUS OBSTRUCTION
• food
• gallstones
• trichobezoar, phytobezoar
• stercoliths
• worms

25. GALLSTONES
• erosion of a large gallstone through the gall
bladder into the duodenum
• 60 cm proximal to the ileocaecal valve
• recurrent attacks
• air–fluid level in the biliary tree
• The stone may not be visible

26. FOOD
• partial or total gastrectomy
• Fruit and vegetables

27. TRYCHOBEZOARS AND
PHYTOBEZOARS
• firm masses of hair balls and fruit/vegetable fibre
• Psychiatric abnormality
• high fibre intake, inadequate chewing, previous gastric
surgery
• hypochlorhydria and loss of the gastric pump
mechanism

28. STERCOLITHS
• jejunal diverticulum or ileal stricture
• identical to that of gallstones

29. WORMS
• Ascaris lumbricoides
• children, the institutionalised and those near the tropics
• attack frequently follows the initiation of anti-helminthic
therapy
• Debility is frequently out of proportion to that produced by
the obstruction.
• eosinophilia or the sight of worms within gas-filled small
bowel loops

31. OBSTRUCTION BY ADHESIONS AND
BANDS
• Adhesions
• most common cause
• in the early postoperative period difficult to
differentiate from paralytic ileus
• peritoneal irritation results in local fibrin production
• Early fibrinous adhesions may disappear

32. CAUSES OF INTRA-ABDOMINAL
ADHESIONS
• Sites of anastomoses reperitonealisation of raw
areas trauma vascular occlusion
• Talc, starch, gauze, silk
• Peritonitis, tuberculosis
• Crohn’s disease
• Radiation enteritis

33. • Bands
• obliterated vitellointestinal duct
• a string band following previous bacterial
peritonitis
• a portion of greater omentum, usually adherent
to the parietes

34. ACUTE INTUSSUSCEPTION
• one portion of the gut becomes invaginated within an
immediately adjacent segment
• Children between 5 and 10 months of age
• 90% of cases are idiopathic
• upper respiratory tract infection or gastroenteritis may
precede
• hyperplasia of Peyer’s patches in the terminal ileum

35. • Weaning, loss of passively acquired maternal immunity and
common viral pathogens
• Meckel’s diverticulum, polyp, duplication,Henoch–Schönlein
purpura or appendix
• After the age of 2 years, a pathological lead point is found in at least
one-third of affected children
• Adult cases are invariably associated with a lead point
• polyp (e.g. Peutz–Jeghers syndrome), a submucosal lipoma or other
tumour

36. PATHOLOGY
• entering or inner tube
• the returning or middle tube
• the sheath or outer tube (intussuscipiens)
• the apex
• blood supply of the inner layer is usually impaired
• ileocolic colocolic

38. CLINICAL FEATURES OF
INTUSSUSCEPTION
• episodes of screaming and drawing up of the legs
• for a few minutes and recur repeatedly
• child appears pale
• Vomiting
• blood and mucus the ‘redcurrant jelly’ stool

39. • a lump
• feeling of emptiness in the right iliac fossa (the
sign of Dance)
• apex may be palpable or even protrude from
the anus

41. VOLVULUS
• twisting or axial rotation of a portion of bowel about its
mesentery
• closed loop of obstruction
• primary or secondary
• congenital malrotation of the gut, abnormal mesenteric
attachments or congenital bands
• volvulus neonatorum, caecal volvulus and sigmoid volvulus

43. CLINICAL FEATURES OF VOLVULUS
• Volvulus of the small intestine
• lower ileum
• Caecal volvulus
• first the obstruction may be partial, with the passage of
flatus and faeces
• tympanic swelling in the midline or left side of the
abdomen

44. • Sigmoid volvulus
• intermittent followed by the passage of large
quantities of flatus and faeces
• Abdominal distension associated with hiccough and
retching
• vomiting occurs late
• Constipation is absolute