Equine Colic PDF

COURSE: EQUINE MEDICINE(VMD VI) Topic: Equine colic DR. O.O. AKINNIYI Department of Veterinary Medicine, University of Ibadan 1  Colic The term “colic” comes from the Greek word koli...

COURSE: EQUINE MEDICINE(VMD VI) Topic: Equine colic DR. O.O. AKINNIYI Department of Veterinary Medicine, University of Ibadan 1  Colic The term “colic” comes from the Greek word kolikos meaning “suffering in the colon”. Equine colic is defined as a general manifestation of abdominal discomfort or pain in the horse, specifically associated with discomfort or pain originating from the gastrointestinal tract. The nature of some abdominal discomfort may be non-gastrointestinal in origin (false colic), such as those resulting from other abdominal organs (e.g., bladder stone and ovarian problems). Equine colic by Dr. O.O Akinniyi 2  Colic Reasons horses are generally more prone to colic compared to most other domestic animals 1) Anatomy of the digestive system: 2) Hindgut fermentation: 3) Inability to vomit: 4) Eating habits: 5) Stress and management factors: 6) Parasite burden: Equine colic by Dr. O.O Akinniyi 3  Causes of Colic Causes of colic: 1) Obstruction: a) Simple (non-strangulating) obstructions: A blockage or narrowing of the intestinal lumen that impedes the normal passage of ingesta without compromising the blood supply to the affected segment of intestine. A subset of this is impaction (caused by the accumulation and dehydration of ingesta within the intestinal lumen). Examples: Pelvic flexure impaction, cecal impaction b) Strangulating obstruction: An obstruction that not only blocks the intestinal lumen but also compromises the blood supply to the affected segment of intestine. Examples: Small intestinal volvulus, large colon torsion, or strangulating lipoma Equine colic by Dr. O.O Akinniyi 4  Causes of Colic 2) Gastrointestinal Inflammation: a) Enteritis (inflammation of the small intestine), colitis (inflammation of the large intestine), and typhocolitis (inflammation of the cecum and colon). GIT inflammation result from infections, dietary changes, or other irritants, leading to inflammation of the colon and associated symptoms like abdominal discomfort, diarrhea, and potential systemic complications like dehydration and endotoxemia. Equine colic by Dr. O.O Akinniyi 5  Causes of Colic 3) Gastrointestinal Distension or Gas Accumulation: This occurs when there is an excessive buildup of gas or fluids within the intestines, causing them to become distended and painful. It can be caused by factors like dietary changes, overeating, or disruptions in the normal digestive process. Equine colic by Dr. O.O Akinniyi 6  Causes of Colic 4) Displacements or Torsions (twists): Displacements occur when a portion of the intestine becomes displaced from its normal anatomical position, potentially leading to obstruction or compromised blood flow. Torsions, or twists, involve the intestine becoming twisted upon itself, resulting in a complete obstruction and strangulation of the affected segment. Equine colic by Dr. O.O Akinniyi 7  Causes of Colic 5) Parasitic Infestations: Heavy infestations with parasites like strongyles, ascarids, or tapeworms can cause intestinal irritation, inflammation, and obstruction, leading to colic symptoms. Equine colic by Dr. O.O Akinniyi 8  Causes of Colic 6) Other Causes: a) Gastrointestinal ulcers: Ulcers in the stomach or intestines can cause pain and discomfort, potentially leading to colic episodes. b) Metabolic or endocrine disorders: Conditions like hyperlipidemia (high blood lipids) or equine metabolic syndrome can predispose horses to impaction colic. c) Abdominal masses or tumors: Growths or masses within the abdomen can exert pressure on the intestines, causing obstruction or discomfort. d) Abdominal trauma: Injuries or trauma to the abdominal region can lead to internal bleeding, perforation, or damage to the gastrointestinal tract, resulting in colic signs. e) Abdominal organ diseases: Problems with organs like the liver, spleen, or kidneys can sometimes manifest as abdominal discomfort, mimicking colic symptoms (referred to as "false colic"). Equine colic by Dr. O.O Akinniyi 9  Colic Clinical signs for colic The most common signs include pawing repeatedly with a front foot, looking back at the flank region, curling the upper lip and arching the neck, repeatedly raising a rear leg or kicking at the abdomen, lying down, rolling from side to side, sweating, stretching out as if to urinate, straining to defecate, distention of the abdomen, loss of appetite, depression, and decreased number of bowel movements. It is uncommon for a horse with colic to exhibit all of these clinical signs. Although they are reliable indicators of abdominal pain, the particular clinical signs do not indicate which portion of the GI tract is involved or whether surgery will be needed. Equine colic by Dr. O.O Akinniyi 10  Colic TYPES/CLASSIFICATION OF COLIC 1) Tympanic (flatulent) colic a) Aetiology/pathogenesis Flatulent colic results from accumulation of excessive volumes of gas in the gastrointestinal tract. The overdistension of the viscera stimulates pain and pressure receptors causing mild to severe colic. The condition is usually due to increases in fermentation or ineffectual gastrointestinal motility or may be secondary to partial luminal obstruction. Distension inhibits vagal motility while fermentation continues. Since the release of gas is normally dependent on escape through the gastrointestinal tract, gas accumulates in the stomach, caecum and large colon. Equine colic by Dr. O.O Akinniyi 11  Colic TYPES/CLASSIFICATION OF COLIC b) Causes interruptions in gastrointestinal motility from stress, excitement or pain. impactions. displacements. late pregnancy. ileus secondary to anaesthesia, surgical manipulation of intestines, vascular compromise (thromboembolic colic) and liver disease. Contributory factors related to management include: feeding highly fermentable substrate (grain overload). feeding horses when exhausted or overheated. cold water engorgement and poor feed quality. Behaviour-associated contributory factors include: inadequate mastication. rapid feed engorgement. Equine colic by Dr. O.O Akinniyi 12  Types of Colic c) Clinical signs The temperature, pulse and respiratory rate will usually be elevated in proportion to the clinical signs. The mucous membranes are pale, and the respirations become more rapid and shallow as the distended viscera occupy a greater proportion of the abdominal cavity and place pressure on the diaphragm. Because the stomach is situated immediately adjacent to the diaphragm, shallow respirations occur more consistently with gastric tympany. Rectal examination reveals gas-filled sections of intestine. The shape of the abdomen changes in response to the intraabdominal distension. Large colon tympany tends to result in bilateral abdominal distension, while caecal tympany often flattens and elevates the region of the right paralumbar fossa. Auscultation of the abdomen is valuable in determining the presence or absence of intestinal sounds. Percussion will aid in identifying more accurately the region of gaseous distension. The rate and location of gas accumulation tend to govern the intensity of pain. Gastric distension results in severe signs of pain, while with distension of the caecum and colon the pain tends to be dull and intermittent. Equine colic by Dr. O.O Akinniyi 13  Types of Colic d) Treatment The primary objective of therapy is to evacuate the gases from the region of distension and to prevent its formation. 1) Stomach tubing 2) Medical treatment should include supportive therapy to relieve pain. Mineral oil is often used to coat fermentable substrate and to lubricate the food material within the gastrointestinal tract for easier passage. 3) Decompression by trocharization should be used only when the sublumbar fossae are very distended, to prevent rupture. Trocharization of the caecum is carried out via the right sublumbar fossa. The site is clipped and surgically prepared. A local anaesthetic skin bleb. Insertion of a 10-cm, 14- or 16-gauge needle through the abdominal wall into the caecum. A rush of gas from the needle will occur immediately, and the needle should be left in place until the flow ceases. A broad spectrum antibiotic (10 to 20 mL) is injected through the needle as it is withdrawn as an aid to the prevention of septic peritonitis and localized infection in the abdominal wall. Systemically administered antibiotics may further suppress diffuse septic peritonitis. Equine colic by Dr. O.O Akinniyi 14  Types of Colic 2) Impaction colic a) Introduction and aetiology Impaction is one of the most common medical colics encountered by equine practitioners. Diagnosis is seldom difficult, and impaction colics, particularly those of the large colon, can usually be resolved with conventional therapy. The primary objectives of therapy are: to maintain hydration. to provide gastrointestinal lubrication. to stimulate gastrointestinal motility. to control pain. In the majority of cases of impaction the obstructing material comprises ingesta of a drier than normal consistency, but extraneous materials such as sand or foreign objects, like nylon hay nets, may be the cause. Equine colic by Dr. O.O Akinniyi 15  Types of Colic b) Clinical signs Rapid consumption of excessive amounts of corn can result in gastric and duodenal impactions. Pain is usually moderate and frequently intermittent. Signs include pawing, lying down and flank watching. Horses with an impacted pelvic flexure located within the pelvis adopt a stance for urination frequently and appear to find relief by lying in dorsal recumbency. The pulse may be slightly raised (40–50 per minute) with increases related to hypovolaemia and pain. The packed cell volume (PCV) and plasma protein are often normal but can be slightly increased if the impaction involves the small intestine or if it has been present for more than 24 hours in the large colon or caecum. Auscultation of the abdomen usually reveals a decrease in borborygmi, but in horses with large colon impactions, bouts of pain are often concurrent with bowel activity. Equine colic by Dr. O.O Akinniyi 16  Types of Colic c) Diagnosis Rectal examination Sand impactions may be suspected whenever faeces retrieved during rectal examination contain sand or grit. If water is added to faecal material in a rectal sleeve and massaged, the sand will settle into the fingers of the glove. Caecal impactions are particularly difficult to assess since digesta may bypass the caecum while the impaction is present Equine colic by Dr. O.O Akinniyi 17  Types of Colic d) Treatment Medical management of colonic impactions is relatively simple and involves the use of nasogastric intubation for lubrication and hydration, parenteral fluid therapy and the control of pain. 1. Lubrication of the intestinal tract is achieved using mineral or vegetable oil (4 to 8 L) either on its own or mixed with electrolyte supplements. This should be administered via a nasogastric tube by gravity or by carefully using a stomach pump. If necessary this is repeated at 12 and 24 hours. 2. Since softening of the obstruction requires gut motility to mix the oil with the mass of ingesta, it is important to use an analgesic which does not depress colonic contractions. Flunixin meglumine 0.5–1.0 mg/kg at 8- to 12-hour intervals is the analgesic of choice. 3. While not necessary in horses with mild impactions of short duration, the intravenous administration of balanced electrolyte solution may be of value in horses with large or firm impactions. The goal of IV fluid administration is to increase plasma volume and decrease osmotic pressure of plasma thereby allowing fluid to move into the extracellular space with subsequent secretion into the bowel lumen. However the efficacy of this treatment is uncertain. Equine colic by Dr. O.O Akinniyi 18  Types of Colic 4) They should be allowed water ad libitum, but all food should be withheld until the impaction has cleared and then reintroduced slowly over 48 hours. 5) Surgical removal of impactions is indicated whenever a definitive diagnosis confirms that the obstruction cannot be cleared medically as with enteroliths or faecoliths or when sustained medical treatment has become unsuccessful and the horse becomes subject to bowel necrosis identified by changes in peritoneal fluid. 6) Meconium retention in neonates rarely requires surgical interference. Enemas are a mainstay of treatment for small colon meconium impactions. Warm water liquid detergent enemas (half a teaspoonful of liquid detergent in 500 mL of water) are gentle to the mucosa and effective. Acetylcysteine retention enemas are now widely used and have proved highly successful. 7) Initially, medical therapy is warranted. Administration of Psyllium hydrophilia mucilloid (0.25 to 0.5 kg/500 kg in 4 to 8 L of water by stomach tube) may facilitate passage of sand. Equine colic by Dr. O.O Akinniyi 19  Types of Colic e) Prevention avoiding abrupt change to diet, providing adequate water supply. maintaining adequate parasite control and dental care. removing foreign objects such as baling twine from food sources. Equine colic by Dr. O.O Akinniyi 20  Types of Colic 3) Displacement (Extra-Luminal) colic It occurs due to mechanical distortion or obstruction of intestine with consequence of interfere with blood supply. A volvulus is a twist along the axis of the mesentery, a torsion is a twist along the longitudinal axis of the intestine. Occlusion of the blood supply means that it is a painful condition causing rapid deterioration and requiring emergency surgery. Intussusceptions most commonly occurs at the ileocecal junction and requires urgent surgery. It is almost always associated with parasites infection, usually tapeworms. Equine colic by Dr. O.O Akinniyi 21  Types of Colic 4) Spasmodic colic a) Introduction It is a functional intestinal disorder that is rarely associated with histological changes of the mucosa. It is attributed to an increase in vagal tone causing increased peristalsis and a propensity to spasm. Equine colic by Dr. O.O Akinniyi 22  Types of Colic b) Clinical signs The disease is characterized by severe paroxysmal attacks of colic lasting from 5 to 10 minutes and separated by pain-free intervals during which the horse’s appearance and behaviour are normal. Initially systemic effects are very mild. The respiratory and pulse rates increase little during bouts of pain and return to normal when the horse is quiet. Faeces may be passed frequently and in small amounts and may have a soft to semi-liquid consistency. Equine colic by Dr. O.O Akinniyi 23  Types of Colic c) Treatment The administration of a spasmolytic/analgesic drug combination such as hyoscine/dipyrone will quickly abolish the spasm and thereby relieve the pain. It is therefore both diagnostic and therapeutic. The treatment may be repeated after several hours if necessary, but most cases show no recurrence of colic when the effects of the initial injection wear off. Equine colic by Dr. O.O Akinniyi 24  Types of Colic 5) Strangulating colic Caused by a complete obstruction of the intestine, leading to compromised blood supply. 6) Non-strangulating colic or Simple obstructive colic There is a partial or complete obstruction in the intestine, but without compromising the blood supply to the affected segment. This can be caused by impactions, displacements, or other obstructions that do not strangulate the intestine. 7) Inflammatory colic (Enteritis/Colitis) Caused by inflammation of the small or large intestine. Equine colic by Dr. O.O Akinniyi 25  Diagnosis of Colic 1) Signalment A. The age of the horse should signal the veterinarian to consider specific conditions – for example, meconium impaction in a foal 1 to 2 days old; ileal intussusception in yearlings or strangulating lipomas in horses older than 15 years. B. Some conditions have a sex predisposition. Inguinal herniation affects stallions while large colon volvulus and uterine torsion typically affect mares. B. The breed of horse may occasionally suggest certain disorders. Large-bodied horses appear to have a high prevalence of left dorsal displacement of the large colon and Standardbreds have a predisposition to inguinal hernia Equine colic by Dr. O.O Akinniyi 26  Diagnosis of Colic 2) History 3) Clinical examinations a) Cardiovascular system i) Rate and quality of pulse ii) Appearance of mucous membranes. b) Examination of abdomen i) Abdominal distension. ii) Auscultation and palpation. iii) Rectal examination. iv) Abdominal paracentesis. v) Nasogastric intubation. vi) Imaging techniques c) State of peripheral perfusion and hydration (PCV, capillary refill time, Total protein) Equine colic by Dr. O.O Akinniyi 27  Diagnosis of Colic 4) Laboratory investigations a) Faecal examination Equine colic by Dr. O.O Akinniyi 28  THE DECISION FOR SURGERY Surgical intervention is indicated: 1. When the exact cause of the colic can be diagnosed and the obstructing lesion requires surgery for its correction. 2. When there is no exact diagnosis but there is sufficient evidence to indicate that surgery is the only means of saving the horse’s life. 3. When horses with recurrent colic over a period of days or weeks are suspected of having partial obstruction due to adhesions, neoplasia etc. Equine colic by Dr. O.O Akinniyi 29 Equine colic by Dr. O.O Akinniyi 30 Equine colic by Dr. O.O Akinniyi 31