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Horse colon displacement

Presented by :Rajeev Kumar MishraL2015V38MDepartment of veterinary MedicineCredit seminar

Gastro Intestinal Tract of Horse

1. Mouth2. Pharynx3. Esophagus4. Diaphragm5. Spleen6. Stomach7. Duodenum8. Liver, upper extremity9. Large colon10. Coecum11. Small intestine12. Floating colon13. Rectum14. Anus15. Left kidney and its ureter16. Bladder17. UrethraSource:-United States Department of Agriculture Leonard Pearson Rush Shippen Huidekoper Ch. B. Michener W. H. Harbaugh

Colon

Descending colon(Small colon)

Ascending colon(Large colon)

Transverse colon

Ascending colon3-4 metres long, 20-30cm in diameter & 80 liters capacity.

45% of the horses digestive tract, compared to 17% of Human.Microbial digestion (fermentation) continues of Fibres Absorption, B group of vitamins & Phosphorus.Begins at cecocolic orifice & terminates at transverse colon

Continue.Begins at lesser curvature of the base of caecum.

Moves caudally up to pelvic inlet as Left ventral colon Sternal Flexure

Pelvic FlexureMoves cranially up to Diaphragm as left dorsal colon

Passes caudally, on reaching medial surface of the base of ceacum it turns left

Transverse colonDiaphragmatic Flexure

Anatomical variation throughout colon

At pelvic region the diameter of colon decreases markedly and turns back.Initial portion of unsacculation.

Right dorsal colon is closely attached to right ventral colon by a short intercolic foldAnd to body cavity by common mesenteric attachment with base of ceacum, no such attachment Is seen in left colon.Transverse colon is fixed firmly to the most dorsal aspect of abdomen by fibrous mesentery

Colonic Motility PatternIt is under the control of pacemaker located at pelvic flexure.The pacemaker sense either the size or the consistency of feed particle.

Normograde peristalsis :- Left ventral colon to left dorsal colon

Retrograde Peristalsis :- from pelvic flexure to sternal flexure.Sufficiently digested food particlesIf additional digestion necessary.

Etiology or predisposing factorLack of mesenteric attachment to the body wall.

Excess soluble carbohydrate diet, quick fermentation, excessive gas accumulation.

Abrupt change in diet.

Altered colonic motility pattern.

Parturition

Displacement of colonDisplacement of Ascending colon

Displacement of colon

Left dorsaldisplacementRetroflectionRight dorsaldisplacement

Left Dorsal Displacement

In a normal healthy horse, the spleen rests against the left abdominal wall and is connected to the left kidney.Left dorsal displacement is characterized by entrapment of ascending colon in the renosplenic space.

NormalTwistedEntrapment

Pelvic flexureA large colon With pelvic flexure Near diaphragm

When the colon is trapped in this position, it is known as a nephrosplenic entrapment.

Abnormal movement (motility) of the colon causes dysfunction and gas accumulation within the colon, which then floats up or is pushed up into the abnormal position. Another hypothesis is that a feed impaction starts the abnormal movement of the colon.

Spurgeon's Color Atlas of Large Animal Anatomy.Prof. Pat McCarthy (Australian)

Per rectal examinationIf large colon is found to the left and slightly ventral to the left kidney between the kidney and caudo dorsal border of the spleen.

It can be suspected when large colon Is between spleen and body wall or when spleen is displaced medially.

In one study rectal examination was diagnostic in 72% of cases.

Ultrasonographic examinationNephrosplenic Ligament Entrapment

Dorsal spleen and left kidney not visible in left caudal abdomenVisualize ingesta or gas-filled large bowelSpleen ventrally displacedBright hyperechoic reflection dorsal to the spleen from the bowel

False negative diagnosis can result from a gas distended viscus near the left kidney.

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Management Withholding the feed.

Phenylephrine@ 3g/kg/min for 15 Minute, Reduces the spleen size by 25%The Rolling procedure.

PhenylephrinePhenylephrine is a sympathomimetic amine Alpha-1 agonist.

ActionPeripheral vasoconstriction increase in arterial blood pressure; this may lead to a reflex bradycardia, particularly if hypertension occurs.

Reduced cardiac output due to reduced heart rate and increased afterload.

Splenic contraction.

Mydriasis.

Phenylephrine reduces femoral arterial and venous blood flow, therefore may reduce muscle perfusionHardy et al. (1994 ) made a study in 6 healthy horse and found that 3 & 6 g/kg/min for 15 Minute, splenic are was reduced to28 &17% of baseline measurement by 35 minute of end of infusion.

For a 600 kg horse600*3*15=27000mg1 ml of phenylepherin in 100 ml of NSS= 100g/mlTotal required=27000/100=270mlA 16 gauge needle has 52ml/min (maximum)As we have to infuse for 15 min so Per ml fluid 270/15= 18ml /min

This treatment combined with exercise, has a reported efficacy of 92% (11 out of 12) in horses with low gaseous distension of the colon

Side effectBradycardia with atrioventricular block second degree.

Increased blood pressure and haematocrit.

The stroke volume remains stable, but the cardiac output decreases with phenylephrine dose.

However, one study showed that this treatment has an increased risk (64 times higher) of internal bleeding (hem thorax, hem peritoneum) in older horses over 15 years

Venner et al.() showed that infusion of adrenaline to 1 mcg / kg / min for 5 minutes in healthy horses results in a decrease of the size of the spleen in 52% of its base value.

Adrenaline is a nonspecific adrenergic agonist, risks associated with its use are potentially larger and less predictable than those of phenylephrine specific for 1 receptors.

Recurs in about 10% of horses.

Surgery

Ablation of nephrosplenic space

colopexy

Colopexy Cont .

Techniques involving suturing the dorsal and ventral colon segments together.Should not be usedA technique of suturing the lateral free band of the LVC to the left body wall, approximately 6 cm to the left of midline, is the currently recommended technique.

Markel MD, Meagher DM, Richardson DW: Colopexy of the large colon in four horses. J Am Vet Med Assoc 192:358, 1988Markel MD: Prevention of large colon displacements and volvulus. In Snyder JR, Markel MD (Eds): Advances in Equine Abdominal Surgery. Vet Clin North Am Equine Pract 5:395, 1989

Right Dorsal Displacement

The left colons move laterally around the base of the cecumlie between the cecum and the right body wall.

usually the arterial supply remains intact.The pelvic flexure ends up positioned near the diaphragm.some interference with venous drainage from the affected colon.most common form of this displacement

Clock wise displacement is more common than counter clock wise.cranialcaudal

Pelvic flexure being placed lateral to caecum.

cranialcaudal

Spurgeon's Color Atlas of Large Animal Anatomy.

Colon is palpated between caecum and right body wall.

Rectal examination may reveal the taenia of the colon running transversely across the pelvic inlet. It may not be possible to palpate the ventral caecal band on rectal examination.

The pelvic flexure cannot normally be felt and caecum is often difficult to palpate.

Per rectal examinationNot much significant.

In addition to clinical signs mentioned above, elevation of -glutamyltransferase ( GT) is often noted when moving right colon.Generally in more chronic cases.It happens that initially diagnosed as mere stasis of pelvic curvature and not responding to repeated administration of laxatives turn out to be right movements.

Large intestine distended with gas filled.

In the normal equine abdomen, the ascending colonic vasculature courses in the mesentery along the medial aspects of the colon and should not be visible during transabdominal sonographic examinationVisualization of colonic mesenteric vessels on ultrasound provided a sensitivity of 67.7%, specificity of 97.9%, positive predictive value of 95.8%, and negative predictive value of 81% for large colon right dorsal displacement or 180 large colon volvulus, or bothUltrasonographic examination

Ultrasound image obtained from a horse that presented for colic. Dorsal is to the right of the image. Colonic vessels are identified in the right 13th intercostal space just dorsal to the costochondral junctions with the probe oriented transversely to the spine. Note large colon adjacent to the vessels, identified by a semi-curved appearance and hyperechoic wall to gas lumen interface (arrow). Also note the echogenic mineralized costal cartilage casting an acoustic shadow ventrally (asterisk) and a small amount of free peritoneal fluid external to the mesocolon and vessels dorsally (double asterisk). Right dorsal displacement of the large colon was confirmed at surgery.

ManagementSurgerysurgery must be performed to locate the pelvic flexure, to exteriorize and decompress the left portion of the colon and then to relocate the colon to its normal position by rotating it around the cecal base.The twisting of the colon must be identified and corrected. The prognosis for survival is good, provided that the colonic wall is not damaged during surgery.

Source:

Merck Manual Equine Internal Medicine , By Stephen M. ReedManual of Equine Practice, Reuben j. Rose.Blackwell's Five-Minute Veterinary Consult: Equine, 2nd EditionEquine Hospital Manual, Kevin Corley & Jennifer Stephen.