orientation in clinical science

1. JAI HIND

2. A gastrointestinal condition in
which digested material is
prevented from passing normally
through the bowel.

3.  One of the common cause of acute abdomen
 It can be classified into two types:
Dynamic (mechanical)
Adynamic

4.  Dynamic: where peristalsis is working against a
mechanical obstruction.
 Adynamic: mechanical element is absent
- Peristalsis my be absent(paralytic ileus)

5. DYNAMIC
1.Intraluminal: impacted faeces, foreign bodies,
gallstones, Bezoars.
2.Intramural: tumors, inflammatory strictures,
3.Extramural: hernias, tumors

6. also can be divided into:
1. Small bowel obstruction (SBO)
 rapid dehydration
 Vomiting delayed
 multiple central air-fluid levels seen on AXR
2. Large bowel obstruction (LBO)
 Mild pain
 Vomiting, dehydration late
 E.g -Carcinoma

7.  Acute obstruction:- usually in small bowel
-obstruction central abdominal pain, distension,
early vomiting and constipation.
 Chronic obstruction: -usually in large bowel
- lower abdominal colic & constipation followed by
distension.
 Acute on chronic: short history of distension &
vomiting against background of pain & constipation.
 Subacute obstruction : incomplete obstruction.

8.  Adhesions- 40%
 Tumors -15%
 Inflammatory- 15%
 Obstructed hernia-12%
 Intraluminal-10%
 Miscellaneous -8%

9. Irrespective of etiology or acuteness of onset:
Proximal to obstruction
Increased fluid secretion  abdominal distention
Accumulation of gas  abdominal distention
Increased intraluminal pressure
 Vomiting
 Dehydration
Increased peristalsis to overcome obstruction  increased bowel
sounds
Decreased reabsorption with time and flaccidity to prevent vascular
damage from high pressure
Distal to obstruction: nothing is passed & bowel collapse 
constipation

10. The four features of intestinal obstruction:
-abdominal pain
-vomiting
-distension
-constipation
Vary according to:-
location of obstruction
Duration of obstruction
underlying pathology
intestinal ischemia

11. Abdominal pain
- colicky in nature, around the umbilicus in SBO
while in the lower abdomen in LBO
- if it becomes continuous, think about perforation
or strangulation.
- does not usually occurs in paralytic ileus.
Vomiting
-starts early in SBO and late in LBO
-As obstruction progresses vomitus alters from
digested food to faeculent due to enteric bacterial
overgrowth
Distension
-more with lower obstruction

12. Constipation
-more with lower or complete obstruction
- constipation is either absolute (no feces or
flatus)
cardinal feature of complete Int.Obst.
or relative (flatus passed).
 it does not apply in
-Richter’s Hernia
-Gallstone obturation.
-mesentric vascular occlusion.
- obstruction associated with pelvic abscess.
-diarrhea may be present with partial obstruction

13. Dehydration
 More common in small bowel obstruction. due to
repeated vomiting .
 Secondary polycythemia due to raised B.urea &
hematocrit.
Pyrexia
 Onset of ischemia.
 Intestinal perforation.
 Inflamation associated with int. obst.

14. In strangulation:
 severe constant abdominal pain
 fever
 tachycardia
 shock

15. General examination-
Vital signs
Signs of dehydration –tachycardia, hypotension
dry mucus membrane, decreased skin turgor, decreased urine
output
Inspection
distension, scars, peristalsis, masses, hernial orifices
Palpation
tenderness, masses, rigidity
Percussion
tympanitic abdomen
Auscultation
high pitched bowel sound or silent abdomen
*Examine rectum for mass, blood, feces or it may be empty in case
of complete obstruction

16.  Hemogram - WBC (neutrophilia-strangulation)
 Plain AXR
 Sigmoidoscopy (carcinoma, volvulus)
 Contrast x-ray
 CT abdomen.
 Usg

17. When distended by gas:
 Jejunum is characterized by valvulae
conniventes(completely pass across the width &
regularly placed)
 Ileum is featureless.
 Caecum is shown by rounded gas shadow in RIF.
 Colon shows haustral folds.
 Fluid level appears later than gas shadow
 Two fluid level in small bowel considered normal.
 No. of fluid level is proportional to degree of
obstruction and distal site in small bowel.

18.  Colonic obstruction does not commonly give rise to
small bowel fluid level unless advanced.
 Associated with large ammount of gas in caecum.
 Ba-follow through is contraindicated in acute
intestinal obstruction.

19.  Three main measures-
- GI drainage
 Fluid &Electrolyte replacement
- Relief of obstruction, usually surgical

20. Treatment
Conservative:
-Nasogastric aspiration by Ryles tube
-IV fluids- volume varies depending on
dehydration
-NPO
-urinary catheter
-check temp. and pulse 2 hourly
-abdominal examination 8 hourly
-Broad spectrum antibiotics initiated early-
reduce bacterial overgrowth.

21. https://kgmu.org/download/virtualclass/Surgical%20Ga
stroenterology/intestinal%20obstruction%202.ppt
References