intestinal obstruction
DESCRIPTION
FROM Dr.MUDASIR BASHIRVETERINARY SURGERY AND RADIOLOGYI.V.R.ITRANSCRIPT
Mudasir BashirDIVISION OF SURGERYAND RADIOLOGY-IVRI
Blockage of aborad flow of intestinal contents (chyle).
Classification (etiological)
Intestinal Obstruction
Mechanical Functional
Intraluminal(foreign bodies)
Intramural(tumors and polyps)
Intussusception Volvulus
Hypodynamic state (ileus) Strangulation/ incarceration
Congenital
Clinical Signs
Depend upon :-1. Location
More orad –more acute signs (secretion- absorption)
More aborad – mild, non specific and chronic signs
Animals with more orad obstruction respond better to fluid and electrolyte therapy.
Obstruction in duodenum and proximal jejeunum-
* Acute vomition especially post-prandial.
* Praying posture Obstruction in mid and caudal jejeunum
– *mild, non specific and chronic signs. *Letharginess, anorexia, oligodipsia
and scanty stool Intussusception – Bloody, fetid smelling
feces
2. Severity Complete – significant and early signs Partial – few or no signs (in later
stages)
3. Duration Long standing obstruction – severe
signs Early obstruction – few non specific
signs.
General signs
Depression Lack of responsiveness Halitosis Dehydration with dry mucosa Moaning Painful abdomen (treading and stretching
out, kicking at belly, lying on ground) Retching Bilateral lower abdominal distention at later
stages
Pathogenesis Obstruction Bowel distention (increased secretion
reduced absorption, hypomotility)
Gas production, lack of absorption
Progressive distention, fluid accumulation, emesis
Systemic dehydration
Reduced venous return
Poor tissue perfusion
Obstruction of venules and lymphatics in bowel wall
Edema of bowel wall
Ischaemia of bowel wall
Necrosis of bowel wall
Enterotoxemia
Death
Rupture of bowel wall
Peritonitis
Sepsis and septic shock sepsis with septic shock occurs as a result of host
response to bacterial signal molecules-endotoxin of gram negative,exotoxins of peptidoglycan,lipotechoic acid,etc.
Toll-like receptors –essential in innate recognition of microbial signal molecules in triggering acquired immunity.
Ten types of TLRs have been found.TLR-4 is essential for lps signelling.
Biological effects of LPS-induced host immunolgical responses are-
Increased vascular permeability
Extensive microvascular thrombosis disseminated intravascular coagulation.
Vasodilatation. Decreased myocardial contractility. Fever.
No organ is left by sepsis-multiple organ dysfunction syndrome.
Following are the effects of sepsis and septic shock on different organs:-
Lung-increased alveolar permeability---increased pulmonary fluid----decreased oxygen exchange.
GIT-haemorrhagic necrosis of mucosa due to ischaemia.
Kidney-acute tubular necrosis---acute renal failure.
Liver-stasis of bile,focal necrosis and jaundice. Endocrine and metabolic effects-increased
levels of cortisol,catecholamines and glucagon—increased proteolysis,lipolysis and gluconeogenesis.
Heart-decreased myocardial function--increased
Systolic and diastolic ventricular volume with a decreased ejection fraction.
strangulation obstruction Strangulation—intestinal wall integrity
disturbance—ischaemia/haemorrhagic intestinal wall infarction—anoxia and necrosis of bowell wall—bacterial growth and multiplication{bacteroids,clostridium,coliforms}—penetration of bacterial products into peritonium—through portal lymphatic—blood stream—septic shock.
Diagnosis
History Clinical findings Physical examination – abdominal
palpation Imaging
Radiography Ultrasonography Laparoscopy
Measurement of diameters Laboratory examination
1. Radiography a) Plain Dilated and gas filled loops of bowel Identifiable foreign body Clumping of bowel + intestinal gas
pattern resembling rows of tear drops shaped lucencies arranged in palisades = linear foreign body
b) Contrast radiography May take 6-24 hrs
Barium (insoluble contrast agent) Adv. - more details - soothing effect on irritated bowel Disadv. – very irritating to peritoneum if spilled
out Diatrizoate meglumine (soluble contrast agent) Adv. – less likely to cause peritonitis Disadv. – poorer details - increases dehydration (hypertonic).
Linear foreign body
2. Ultrasonography More rapid method More chances of false -ve and false +ve Technique of choice for intussusception
3. Laparoscopy
4. Measurement of diameters Max. SI diameter:L5body ht. At narrowest
point = 1.6 (normally) >2 = obstruction
5. Laboratory findings (abdominal fluid)• Increased total protein (>2.5 g/dl)• Increased cell count (> 10000 cell/cmm.)
Intussusception-Radiographic trident appearance
Transverse Longitudinal
Laparoscopy (Intestinal polyps)
Foreign bodies Most common cause of intestinal
obstruction in animals.1. Space occupying
Round smooth Complete obstruction Trail of distended bowel (aborad
propulsion) Pressure necrosis
Sharp edged Partial obstruction Perforates bowel wall
2. Linear foreign body Thread, nylon stockings, rope, string,
carpet etc. Most frequent in cats One end – tongue base, pharynx, pylorus Other end – carried to intestine through
peristalsis Mesenteric side – perforations Oral examination – most important Abdominal examination – pain, pleating
and clumping of intestine Radiography Rx - surgical emergency - enterotomy (multiple or single)
Tumors Mostly malignant (thoracic radiography
and hepatic ultrasonography).
1. Adenocarcinoma bowel stricture Most common – distal jejunum and
ileum Treatment unrewarding
2. Leiomyoma/ Leiomyosarcoma Impinge on bowel lumen Leiomyoma- good prognosis Leiomyosarcoma- grave prognosis
3. Lymphosarcoma Protein losing enteropathy – most
common Chemotherapy is treatment of choice
4. Adenoma Also known as polyps Partial obstruction Irritation - intussussception
Polyps
Intestinal tumors
Intussusception Invagination or telescopy of intestines Intussusceptum – intussuscipiens Hypermotility (irritataed bowel) Partial obstruction – complete obstruction Ileo-caeco-colic junction – most common
site Common in young pups
Rx Laparotomy – release of invagination with
or without intestinal resection and anastomosis.
Intussusception ant ileo-caeco-colic junction
Volvulus
Twisting of intestine on its mesenteric axis
Susceptibility – GSD – dogs with GSD blood – other
breeds. Radiograph – massive dilation of
multiple loops of bowel in stellate pattern originating from a central focus.
Prognosis – very grave.
Intestinal volvulus
Intestinal volvulus
Congenital defects
Atresia of intestinal segments Signs visible in neonatal life Intestinal resection and anastomosis -
only cure.
Ileus / Pseudo- obstruction
Def. – ineffective aborad intestinal propulsion Occurs – (a) after surgery (b) secondary to diseases (uremia, peritonitis, pancreatitis) Mainly due to electrolyte disturbances Usually transient Rx – (a) prokinetic drugs (b) correction of electrolyte disturbance (c) correction of underlying disease
Strangulation / Incarceration
Entrapment of intestines in traumatic wall hernia, omental tears, congenital hernia, mesenteric rents, volvulus and intussusception.
Compression of intestinal veins – inhibition of arterial flow – mucosal degeneration – endotoxemic shock and peritonitis (perforation)
Stabilize the animal – enterotomy / anastomosis
Prognosis - grave
Causes of strangulation
Appearance of strangulated intestines in a horse suffering from colic
Intestinal Surgery GENERAL PRINCIPLES
1. Maintenance of fluid and electrolyte imbalance (hypokalemia, hypochloremia, hyponatremia and metabolic acidosis)
2. Antibiotic prophylaxis (contaminated or clean contaminated surgery)
3. Assessment of intestinal viability4. Choice of suture material Monofilament synthetic absorbable
(polydioxanone, polyglyconate)
5. Choice of suture pattern Submucosa (incorporation)
A. * Single layer – preferred * Double layered – Avascular necrosis of
inverted cuff of tissues - Narrowing of lumen.inadequate submucosal apposition.
.
B. * Apposition – preferred method * Eversion - adhesions * Inversion – reduced intestinal lumen
Interrupted single layered serosubmucosal suture pattern – gold standard
6. Suture line enforcement Prevention of leakage Revascularization A. Omental wrappingB. Serosal patching (surgical parachute)
Enterotomy and Anastomosis