CHIRANTAN MANDAL 3rd MB proffesional Part II Medical College kolkata 5th April 2013

1. Pathophysioliogy of
Intestinal
obstruction
Chirantan Mandal
3rd MB Proffessional part II
Dept of Surgery, Medical College Kolkata

2. Intestinal obstruction
• Dynamic - peristalsis is working against a
mechanical Obstruction
• Adynamic -
absent peristalsis (Paralytic ileus)
non-propulsive peristalsis form

3. Changes proximal to Bowel obstruction
Intestinal Obstruction & Increased Peristalsis
Obstruction not relieved
Peristalsis ceases
Fluid collection Proximal to obstruction
(Bacterial multiplication and Toxaemia)
Flacid, paralysed, dialated Bowel
Inflammation (bowel Wall)
Cytokine releasing Macrophages Accumulates
Increased release of NO with ROS production

4. Changes at site of Bowel obstruction
Venous Return Inpaired
increased intraluminal pressure exceeding bowel wall venous pressure
Congestion & edema of Bowel
Further Dialatation & Ischaemic Injury
Involvement of Arterial Supply
Blockage of arterial perfusion
Loss of Peristalsis
Bowel wall necrosis
Gangrene
Bacterial Toxin release & mucosal damage
Translocation to submucosa
Toxaemia

5. STRANGULATION

6. Closed-loop obstruction
Loop of Bowel obstructed at entry
and Exit point of a closed loop
i.e at proximal and distal loop of
bowel

7. Closed-loop obstruction
Gangrenous Bowel

8. External Hernia

9. Internal hernia
portion of the small intestine becomes
entrapped in the retroperitoneal fossae
other Sites of Internal Hernia :-
• the foramen of Winslow
• a hole in the mesentery
• hole in the transverse mesocolon
• diaphragmatic hernia

10. transverse colon volvulus
Volvulus
Twist in axis of bowel
loop type CV
Each arrow on the diagram of the normal colon
represents a possible torsion mechanism
bascule type ceacal volvulus
(Constricting Band Around Ascending Colon)
bascule = Sea Saw

11. loop type CV
Caecum distended and
found in centre of Abdomen

12. Compound
Volvulus
& Ileosigmoidal
Knotting

13. Intussusception
portion of the gut becomes invaginated
within an immediately adjacent segment
part that advances = apex
Mass = Intussusception
Neck =junction of the entering layer with the mass
strangulating obstruction as the blood supply of the
inner layer
degree of greatest at ileocaecal valve
In children intussusception is ileocolic
(50cm terminaL Ileum)
In Adult colocolic intussusception is common

14. Obstruction by adhesions
and bands

15. Causes
Obstruction by adhesions • Ischaemic areas
• Reperitonealisation of raw areas
• trauma, vascular occlusion
• Foreign material Talc,
• Infection Peritonitis, tuberculosis
• Crohn’s disease
types –
• ‘avscular’ flimsy
• ‘poorly vascular’ dense

16. Obstruction by Bands
Strangulation of Bowel loops by Knotting Diverticulum
Dense Fibrous String attaching one
portion of abdo to other; entraping
intestine into Strangulation
Causes:-
• following previous bacterial peritonitis
• a portion of greater omentum
adherent to the parietes.

17. Bolus obstruction

18. Gallstones Ileus
passage of a GBstone from the biliary tract
into the intestinal tract (by fistulous
connection between the GB & duodenum)
usual location is at or 60 cm proximal
to the ileocaecal valve
obstruction is frequently incomplete or
relapsing as a result of a ball-valve effect.

19. Ascariasis
Obstruction of the small
intestine
due to
Ascaris lumbricoides

20. Trychobezoars &
phytobezoars
firm masses of undigested hair balls &
fruit/vegetable fibre
associated with an underlying
psychiatric abnormality
Phytobezoars
Predisposition to
phytobezoars
• high fibre intake
•inadequate chewing
•previous gastric
surgery
• hypochlorhydria
Trychobezoars

21. Food Bolus obstruction
• may occur after
partial or total
gastrectomy
• when unchewed
articles can pass
directly into the small
bowel.
• Fruit and vegetables
are particularly liable
to cause obstruction

22. Stercolith associated with
Faecal Impaction Diverticulosis and
ileal stricture

23. Meconeum Ileus
Meconium becomes thickened and causes mechanical obstruction in ileum
(associated with cystic fibrosis )
Hypertrophy dialatation of Proximal Bowel
Distal ileum contains Pellets and gets narrowed

24. Congenital Intestinal
Obstruction

25. Duodenal
Atresia
Duodenal Stenosis Fibrous cord Atresia
Complete Atresia With Separation

26. Most common site of Intestinal atresia
Defective fusion of foregut and Midgut
With failure of recanalisation
Associated with
1. Annular Pancreas
2. Down syndrome
3. Maternal polyHydroamnios

27. Fibrous Atresia
Mucosal Atresia
Complete Single Atresia
Complete jejunal Atresia
(Vshaped Mesentry)
with Coiled Ileum
(christmas tree deformity)
Gresifield Classification
Jejunoileal
Atresia
Multiple Atresia

28. Most common at prox. Ileum
Proximal bowel:- dialated & hypertrophy
normal sized Villi
Distal bowel:- collapsed hypertrophied Villi

29. Malrotation

30. Small bowel in right side
colon on left side
Caecum suspended midline

31. Incomplete
Rotation
Most common type
Caecym subhepatic Rt
hypochondrium
LADDs band connects to postr wall
LADDs compresses 2nd part of
Duodenum
Midgut hangs along SMA

32. Reverse Rotation
180deg clockwise
rotation
Colon posterior to
duodenum & SMA

33. Paralytic ileus
(Adynamic )
Intestine Fails to
transmit any
peristalsis due to
failure of
nueromuscular
mechanism
Auerbachs and
Meissners Plexus

34. Thank You

35. Normal Rotation of Midgut

37. Strangulated Bowel due to Omental Adhesion