Colic: the Exam, Treatment, and Prognosis K
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Volume 54 | Issue 1 Article 7 1992 Colic: The Exam, Treatment, and Prognosis K. L. Varner Iowa State University E. L. Reinertson Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/iowastate_veterinarian Part of the Digestive System Diseases Commons, and the Large or Food Animal and Equine Medicine Commons Recommended Citation Varner, K. L. and Reinertson, E. L. (1992) "Colic: The Exam, Treatment, and Prognosis," Iowa State University Veterinarian: Vol. 54 : Iss. 1 , Article 7. Available at: https://lib.dr.iastate.edu/iowastate_veterinarian/vol54/iss1/7 This Article is brought to you for free and open access by the Journals at Iowa State University Digital Repository. It has been accepted for inclusion in Iowa State University Veterinarian by an authorized editor of Iowa State University Digital Repository. For more information, please contact [email protected]. Colic: The Exam, Treatment, and Prognosis K. L. Varner* E. L. Reinertson, D.V.M., M.S.** Horses are especially susceptible to a variety horse's behavior, manifestation and progression of gastrointestinal incidents, manifesting of pain, water consumption and appetite, and tl1emselves as episodes of colic or abdominal frequency of defecation and the consistency of pain. The anatomy of the equine gastrointestinal the feces. It should be noted if the horse had been system is long and has marked variations in its exposed to any excess feed, chemicals, toxins, or diameter which contributes to tl1e increased medications and details of any previous colic incidence of colic. Possible displacements and episodes. Other factors of importance are the twisting may also be attributed to the sparse age, sex, use, and presence of any vices such as attachment of intestinal tract to the abdominal cribbing or pica. Also to be considered is the wall, which leaves areas of the gastrointestinal monetary and emotional value of the horse to the organs to move about freely. owner, as this may be an important factor in the There are many etiologies of colic wl1icl1 can treatment of the horse. be classified into broad groups: obstruction, The decisions concerning severity, treatment, strangulating obstruction, non-strangulating and prognosis of the colic episode are made infarction, intestinal infections or enteritis, based on a complete physical exam. A list of peritonitis, ulceration, and unexplained pain differentials should be established as there are labelled colic. 1 Tl1ere are also many diseases of few pathognomonic signs of a specific disease. non-gastrointestinal origin that may resemble colic, The results of the initial physical exam should be including liver disease; muscle degeneration or recorded for cornparison with subsequent exams. laminitis; pulmonary-pleural disease; urinary tract Often tl1e decision for surgery is based on changes disease; toxicoses; reproductive tract problems; that occur over time. Detection of these trends neurological disease; and occasionally cardiac necessitates accurate recordings. 2 disease. There are also many other specific problems besides these that may cause signs Pain resembling colic. Initial examination of a horse with colic should Initial observation of the horse should occur in determine if the horse needs surgical intervention the stall or paddock without restraint to note its or if medical treatment can be successfully behavior and manifestations of pain. Pain may be employed. Physical examination of a horse evidenced in different manners, such as pawing, experiencing a bout of colic is tl1e most important stretching, lying down, looking at the flank, kicking means of assessment. The exam should be at the abdomen, crouching, grinding of the teeth, carried outthoroughly, systematically, and quickly dog-sitting, rolling, sweating, odd head positioning, in order to institute the appropriate therapy. groaning, or straining to urinate. The severity of A quick history may detenTline the etiology of pain sl10uld also be classified as absence of pain, the colic episode. A general history of management mild pain, moderate pain, severe pain, or should include parasite control, feeding program, depression.3 Previous treatments of analgesics housing and environment, vaccination schedule, may affectthe expression of pain. Pain responses and the presence and status of other 110rses on may make a complete physical exam impossible the premises. Any recent changes in management, and dangerous to the veterinarian, therefore, a including feeding, pasturing, pregnancy, ormedical strong analgesia or general anesthesia should be treatments, should also be noted. employed. Violent severe pain that is not alleviated Tl1e individual history of the horse in question by analgesics is a strong indication for surgery. should be requested. This should include the Severe pain may be caused by strangulation of the large colon or the small intestine, intestinal *Dr. Varner is a 1991 graduate of the College of herniation a.nd strangulation involving the gonads.4 Veterinary Medicine. If severe pain suddenly dissipates and depression **Dr. Reinertson is an Associate Professor of ensues, it is likely that rupture of the stomacl1 or Veterinary Clinical Sciences at Iowa State bowel has occurred. University. 20 Iowa State University Veterinarian Abdominal silhouette be associated with cold extremities. Arrhythrnias due to electrolyte imbalances may produce an The abdominal silhouette of the horse may irregular pulse. If xylazine or detomidine have suggest causes of colic. Cecal involvement may been administered to sedate the horse, a reduced be evidenced by rounding of the right, flank while heart rate or second degree heart block may be left side rounding suggests large colon distention. present. Although laminitis is not associated with Generalized enlargement of the abdomen can acute colic, the digital arteries should be palpated occur with large colon torsion or small intestinal as owners may confuse signs of laminitis, such as volvulus. A pear shaped abdomen suggests fluid sweating, increased heart rate, and recumbency, filled. Enlargement of an umbilical hernia or of the with colic. 6 scrotum may indicate intestinal incarceration with The respiratory rate can be elevated due to obstruction. External palpation or ballottement of abdominal pain and is usually shallow to reduce the abdomen may help determine an etiology. movement of the chest and diaphragm. Significant Splinting of the abdomen may be associated with abdominal distension, as with colon torsions, can parietal pain from peritonitis or pleuritis. In such compromise the horse's thoracic volume, thus cases, the horse may be very resistant to secondarily elevating the respiratory rate. movement and resentful of external abdominal Metabolic acidosis can also cause an elevation in pressure. the rate. Temperature, Pulse, Respiration Mucous Menlbranes, Peripheral Perfusion The temperature, pulse, and respiratory rate A horse's mucous membranes are normally should be taken early in the course of the exam to pale pink with a capillary refill time of two seconds help classify the type of colic. The temperature or less. Hemoconcentration and endotoxemia should be taken before performing a rectal exanl may cause dark, brick red mucous nlembranes as air introduced into the rectum will cause it to with an increased capillary refill time. Severe decrease. One should also remember that most pain, causing catecholanline release and thus non-steroidal anti-inflammatory drugs (i.e.: peripheral vasoconstriction, can cause pale, Banamine) are also antipyretics and may mask a blanched mucous membranes. Pale blue-grey or fever. A normal to slightly elevated temperature cyanotic membranes are due to decreased (up to 101.5°.) may be presentwith obstructions or perfusion and hypoxia due to severe shock from displacements. An elevated temperature, greater endotoxemia, lung compression, or compression than 102°., can signify an infectious agent or the of the caudal vena cava. Capillary refill time presence of pyrogenic agents. Peritonitis, pleuritis, appears to be one of the best indicators of colitis, or enteritis can cause an elevated peripheral perfusion and cardiovascular status as temperature. A subnormal temperature is a grave they relate to su rvival. 7 sign and can occur with severe bowel necrosis or rupture due to circulatory collapse. Auscultation The pulse rate and character is related to pain, vascular volume, cardiovascular status, and Auscultation of the upper, lower right, and left cardiovascular response to endotoxemia. paralumbar regions should be performed, as well Generally, the higher the rate, the greater the as of the ventral abdomen. Colon rnixing is severity of disease. Dehydration and shock may normally heard on the lower sides while cecal increase pulse rate irrespective of pain. Often noises are heard on the upper right. simple obstructions will show a mild elevation of Small intestinal noises are heard on the upper 40 to 70 bpm in pulse rate. Early strangulations left. Normally, fluid gurgling mixed with gas sounds can have 50 to 90 bpm, late strangulations having are heard. There are great variations in the 70 to 120 bpm. Enteritis or peritonitis may show frequency and amplitude of sounds in normal rates of 40 to 100 bpm. 5 The pulse rate may horses. Usually the sounds are two to four times elevate then drop to near normal with transient per minute. Noise increases in frequency and episodes of pain seen with spasmodic or flatulent amplitude with eating and decrease with