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Volume 57 (8) : August, 2004 Irish Veterinary Journal Right dorsal colitis in the horse: minireview and reports on three
cases in Ireland
Noreen Galvin,1 Hugh Dillon2 and Frank McGovern2
1 Bohergoy, Maddenstown, The Curragh, Co Kildare, Ireland2 Troytown Equine Hospital, Green Road, Kildare Town, Co Kildare, Ireland Right dorsal colitis (RDC) is an ulcerative inflammatory bowel disorder of the horse that Key words
has been associated with the administration of non-steroidal anti-inflammatory drugs (NSAIDs), particularly in horses treated when dehydrated or toxaemic. The acute form of Right dorsal colitis, Phenylbutazone, RDC may result in profuse diarrhoea, severe colic, dehydration, endotoxic shock and even death; the chronic form may be manifest by mild to moderate intermittent colic, ventral oedema and weight loss with or without diarrhoea. The most consistent Loss of weight.
laboratory findings are anaemia, hypoproteinaemia, hypoalbuminaemia andhypocalcaemia. Medical management of RDC requires avoidance of NSAIDs, of stressfulexperiences and of large-volume diets. Specific medications such as sucralfate andmetronidazole have been used to treat RDC in the horse. The use of dietary additionssuch as psyllium and corn oil has been mentioned in the literature. RDC has not been reported previously in Ireland or Britain; here we report that thecondition was diagnosed in three horses in Ireland on the bases of a history ofphenylbutazone therapy, clinical signs, clinical pathology and ultrasonography. In two ofthe three horses the diagnosis was confirmed by direct inspection of the affected colonat celiotomy. Irish Veterinary Journal
Volume 57: 467 - 473, 2004
Minireview of the literature
Right dorsal colitis is a specific type of protein-losing, ulcerative inflammator y bowel disorder of the horse that has been There is evidence that dehydration, enterotoxaemia or pre- associated with the administration of non-steroidal anti- existing lesions of the colon increase the risk of RDC amongst inflammatory drugs (NSAIDs), most commonly phenylbutazone horses being treated with NSAIDs such as phenylbutazone or (Karcher et al., 1990). Although the condition is relatively flunixin meglumine. NSAIDs can cause ulceration throughout common in the USA, it has not been reported in Ireland or the entire gastrointestinal tract of horses (MacAllister, 1983; Britain, despite many horses receiving phenylbutazone therapy.
MacKay et al., 1983; Collins and Tyler, 1984). The exact reason In this paper we provide a minireview of the literature on RDC for the localization of ulceration in the right dorsal colon has not and we report the diagnosis of the condition in three horses in been elucidated; however, one hypothesis is that phenylbutazone is bound extensively to roughage and is released afterfermentation in the large colon (Mathio et al., 1986). There isprolonged contact time between the drug and the right dorsal Corresponding author: colon due to the slow transit time and the narrowing of the lumen at the junction of the right dorsal colon and the transverse colon (Cohen, 2002).
Maddenstown, The Curragh, NSAIDs inhibit the cyclooxygenase (COX) enzyme, of which Co Kildare, Ireland there are two known isoforms: COX-1 and COX-2 (Griswold Tel: 087 267 3145; E-mail: [email protected].
and Adams, 1996). COX-1 mediates prostaglandin E2cytoprotection in the gastrointestinal tract; COX-2 is the isoform Volume 57 (8) : August, 2004Irish Veterinary Journal that is responsible for the production of the prostaglandins which are targeted more to inhibition of COX-2 than to associated with inflammation. Drugs such as phenylbutazone, inhibition of COX-1 (MacAllister et al., 1993).
which cause proportionately more inhibition of COX-1 than ofCOX-2, may cause a reduction in cytoprotective effects mediated Avoid stressful situations by prostaglandin E , resulting in hypoxic or ischaemic damage to Decreasing or discontinuing work regimes is important in the the mucosa (Griswold and Adams, 1996).
recovery phase of affected horses (Cohen, 2002). It is desirable The dose of phenylbutazone required to induce ulcerative colitis to avoid any situations that may cause stress (such as changes in was initially thought to be greater than 10mg/kg bwt s.i.d. for management regimes) or may precipitate dehydration (as in long longer than seven to ten days (Meschter et al., 1990; MacAllister, 1983). However, in one study, RDC was induced in two horsesby administering 6mg/kg bwt phenylbutazone s.i.d. for five days while water intake was restricted to half maintenance Large-volume fibre sources should be eliminated to reduce the requirements (Karcher et al., 1990).
mechanical and physical load on the compromised colon, in The variable occur rence of the toxic side ef fects of order to favour mucosal healing (Cohen et al., 1995a; Cohen, phenylbutazone may be attributed to individual variation (i.e., 2002). A low bulk diet, consisting of a pelleted feed and small age, breed, health status, hydration, diet, stress levels and quantities of grass, should be provided in several small feeds duration of treatment). There appears to be a higher incidence in during the day. Generally, a period of three to six months should young horses and ponies, perhaps because young horses that are be allowed for the colon to heal prior to reintroduction of bulk in work are more likely to be prescribed NSAIDs for treatment of musculoskeletal injuries (Cohen, 2002).
The use of psyllium mucilloid, a soluble dietary fibre, may beuseful. When fed intermittently, it acts as a laxative. When fed Clinical aspects continuously, it can result in the production of short-chain fatty Clinical signs of acute RDC may include profuse diarrhoea, acids, which may promote healing and repair of the colonic severe colic, dehydration, endotoxic shock and death. The mucosa (Argenzio, 1994). The recommended dose is 100g once chronic form may be manifested by mild to moderate daily for three to six months. However, control studies on intermittent colic, ventral oedema, weight loss with or without psyllium mucilloid in equine species are lacking. diarrhoea, the duration of which can vary from weeks to several The addition of oils to the diet of horses with RDC has been months (Karcher et al., 1990; Simmons et al., 1990; Cohen et proposed as beneficial (Bueno et al., 2000; Cohen, 2002). The al., 1995a, b; Bueno et al., 2000; Cohen, 2002). The most addition of corn oil, 100 to 200ml daily, also has the advantage consistent clinicopathological features include anaemia, of introducing low-bulk calories to the patient's diet (Cohen et hypoproteinaemia, hypoalbuminaemia and hypocalcaemia al., 1995a). Ensure plentiful water supply at all times to avoid (Karcher et al., 1990; Cohen et al., 1995a, b), all probably due to losses through the damaged mucosa. Anaemia is usually mild,and the PCV rarely falls below 0.25L/L (Cohen et al., 1995a, b; Use of specific medication Bueno et al., 2000; Cohen, 2002). has been shown to prevent ulceration in the gastrointestinal tract of ponies (Collins and Tyler, 1985).
Misoprostal is a synthetic analogue of PGE . However, side Initial reports described RDC as a condition that needs surgical effects (which may include abdominal discomfort) and cost are inter vention; however, such surgical treatments were not likely to limit its use in the horse. Other anti-ulcer medications successful (Karcher et al., 1990; Simmons et al., 1990). While like histamine -receptor antagonists and proton pump inhibitors definitive diagnosis requires exploratory laparotomy, this is are unlikely to be effective in the treatment of RDC as their unlikely to be the best therapeutic approach. Medical function is to decrease gastric acidity (Cohen et al., 1995b). They management is likely to provide a more satisfactory outcome if an may have a role in treating concurrent gastric ulceration.
accurate and early diagnosis can be made on the bases of history, It has been suggested that sucralfate may be beneficial at clinical signs and clinical pathology, and if the owner can be 22mg/kg bwt p.o. t.i.d. (MacAllister and Taylor-MacAllister, persuaded to comply with the therapeutic and dietary constraints 1994). Administration can be relatively inexpensive and it has that must be observed. Medical management is based upon four been used in cases of RDC (Cohen, 1995b).
main principles: avoid further use of NSAIDs, avoid stressful Metronidazole and sulphasalazine have been used in human situations, modify the diet, and use specific medication.
patients to deal with NSAID-induced enteropathies. The effectsof sulphasalazine in the horse have not been evaluated.
Avoid further use of non-steroidal anti-inflammatory drugs Metronidazole has been used in the treatment of RDC (Cohen, If the use of a non-steroidal anti-inflammator y dr ug is 2002). It should be added to the therapeutic regime if secondary unavoidable, use less ulcerogenic drugs, such as ketoprofen, anaerobic infection is suspected. Recently, glutamine has been Volume 57 (8) : August, 2004 Irish Veterinary Journal TABLE 1: History and signalment of the three horses diagnosed with right dorsal colitis
Age (years)
Clinical signs reported
by owner prior to admission
intermittent colic, intermittent colic and diarrhoea.
Duration of signs before admission (days)
Duration of administration of phenylbutazone (days)
Estimated dose of phenylbutazone
5mg/kg/bwt b.i.d. 4mg/kg/bwt b.i.d.
administered (per os)
for two day and 2.5 mg/kg/bwt. b.i.d. for b.i.d. for twelve days TABLE 2: Clinical examination of the three horses on admission
Exhibiting signs of abdominal discomfort Heart rate (per minute)
Respiratory rate (per minute)
Pale, CRT< 2 sec Pale, CRT<2sec Pale, CRT<2sec Mild weight loss Moderate weight loss Oedema between the rami CRT= capillary refill time; L = left side of abdomen; R = right side of abdomen shown to improve the healing and repair of the mucosa in the gain is also a good indicator of progress, if weight loss was a damaged right dorsal colon of horses (Rotting et al., 2002).
presenting sign.
Horses with acute RDC may require intravenous fluid therapy tocombat dehydration and endotoxaemia. Plasma and other Case reports
colloids may be necessary in the acute RDC if the animal is severely hypoproteinaemic. This will increase the plasma oncotic History and clinical examination pressure and aid in the reduction of ventral oedema and oedema A two-year-old Thoroughbred colt in training was admitted to of the bowel wall.
the hospital for investigation and treatment of weight loss and Once medical treatment has been initiated, progress can be intermittent bouts of colic over a period of 30 days. Diarrhoea monitored by assessing the frequency of the colic episodes.
had been present for five to seven days. Seven weeks prior to Monitoring serum total protein and serum albumin can be a admission the colt had been prescribed a seven-day course of oral useful indicator of the healing process: values should increase phenylbutazone for a fore limb lameness. The dose was 2g gradually over two to twelve weeks. Ultrasonography can be used (5mg/kg bwt) p.o. b.i.d. for two days then reduced to 1g p.o.
at regular intervals to monitor the thickness of the wall of the b.i.d. (Table 1). Results of the clinical examination are outlined right dorsal colon and to assess the degree of oedema. Weight Volume 57 (8) : August, 2004Irish Veterinary Journal TABLE 3: Clinical pathology and further diagnostic tests on three horses with right dorsal colitis
Packed cell volume L/L
White blood cell count x 109/L
Neutrophils x 109/L
Serum total protein g/L
Serum albumin g/L
Total serum calcium mmol/L
Faecal occult blood
Worm egg count
Gastric ulceration present on gastroscopy
Abdominal fluid analyses
White blood cells x109/L
Total protein g/L
Thickness of the wall of the right dorsal colon (ultrasound) cm
FIGURE 1:
Further investigations Horse 1. Image of Clinicopathological abnormalities included mild anaemia, severe the abaxial wall of hypoproteinaemia with a hypoalbuminaemia (Table 3). Total serum calcium was decreased. Faecal occult blood test was positive.
Abdominocentesis revealed a grossly normal sample of peritoneal fluid, with an elevated white blood cell content and increased total protein (Table 3). Abdominal ultrasonography was intercostal space.
unremarkable except for an increased thickness (1.3cm) in the The liver and the wall of the right dorsal colon at the level of the 12th intercostal space (Figure 1). lying dorsal to the Initial supportive therapy consisted of intravenous balanced polyionic fluids at 70ml/kg/day, with 2 litres of fresh frozen plasmaadministered over six hours. Three litres of hydroxyethyl starch 6% days. On discharge, packed cell volume (PCV) was 0.27L/L, (7.5ml/kg bwt) was also administered i.v. in the initial 24-hour total protein 25g/L and albumin 11g/L. Follow-up treatment period, followed by 2 litres (5ml/kg bwt) on each of the following included elimination of all high bulk fibre from the diet and two days. On admission, there was no evidence of endotoxaemia; replacement with low volume fresh grass feeds and pelleted however, prophylactic therapy with 3.2g pentoxifylline (8mg/kg bwt) feedstuffs. Psyllium mucilloid (50g) and corn oil (200ml) were p.o. b.i.d. for five days was initiated. Bismuth and salicylate mixture added to the feed twice daily for the following three months. The was administered via nasogastric tube, 1.2 litres (3ml/kg bwt) b.i.d owner was advised to avoid administration of all NSAIDs and the for 48 hours.
colt was withdrawn from training to minimise stress. While in the hospital the colt's appetite was considered normal. High In the initial month following discharge the colt experienced two bulk fibre roughage was withdrawn from the diet and frequent feeds bouts of colic. The first coincided with the accidental feeding of of fresh grass and a commercial pelleted concentrate were fed.
hay. The colt responded favourably to intravenous injections of4mg detomidine (0.01mg/kg bwt) and 4mg butorphanol (0.01mg/kg bwt). The second incident was mild, of short The colt remained bright during his hospitalization and clinical duration and specific treatment was not needed.
parameters were normal. Crystalloid and colloid therapies were One month after discharge the PCV was 0.32L/L, total protein discontinued 72 hours after presentation. Faecal consistency was 36g/L and albumin was 18g/L. Three month after improved within 48 hours and the colt was discharged after five discharge the PCV was within normal limits and total protein was Volume 57 (8) : August, 2004 Irish Veterinary Journal 54g/L with albumin at 25g/L. Training was resumed two weeks Two weeks after discharge the gelding was readmitted for later and at the time of writing (eighteen months after discharge) evaluation of colic, which had not responded to 2g phenylbutazone there has been no report of further problems.
administered i.v. four hours earlier by the referring veterinarian. Atpresentation, the heart rate was elevated at 64 beats/minute; abdominal auscultation revealed poor gut motility in all quadrants.
History and clinical examination PCV was 0.31L/L, total protein was 40g/L and albumin was A five-year-old sporthorse gelding was presented to the hospital 16g/L. On rectal examination, a distended and displaced large for investigation and treatment of a mild colic, which had not colon could be felt cranial to the pelvic inlet. In view of the clinical resolved after the administration of 2g phenylbutazone i.v. by the findings an exploratory celiotomy was performed.
referring veterinarian. Oral phenylbutazone had been prescribed Preoperatively, the gelding received an intravenous injection of 3.3g three weeks previously for a wound on the lateral forearm. The gentamicin (6.6mg/kg bwt) and an intramuscular injection of 6g duration of treatment was fourteen days at a dose of 2g (4mg/kg procaine penicillin (12mg/kg bwt). Anaesthesia was induced with bwt) p.o. b.i.d. for two days and then 1g (2mg/kg bwt) p.o.
intravenous injections of 550mg xylazine (1.1mg/kg bwt) followed b.i.d. for the following twelve days (Table 1). Findings of the by 1.1g ketamine (2.2mg/kg bwt) and 20mg (0.04mg/kg bwt) clinical examination are outlined in Table 2.
diazepam; it was maintained with halothane and oxygen in a semi-closed circuit. A balanced electrolyte solution (Hartmann's) was Further investigations administered continuously during surger y at a rate of Clinicopathological abnormalities included a mild anaemia, leukocytosis, hypoproteinaemia and hypoalbuminaemia (Table A standard midline celiotomy approach was performed. There was 3). Total serum calcium was decreased. Faecal occult blood test gross distension of caecum and the entire large colon. Following was positive. Abdominocentesis revealed a grossly normal sample, initial decompression, the colon was identified on the right side of which had an elevated total protein concentration (Table 3).
the caecal base, having become displaced cranially and then laterally Abdominal ultrasonography was unremarkable, with the right (right dorsal displacement with the colons passing in an anti- dorsal colon wall measuring 0.5cm in thickness at intercostal clockwise direction as viewed from the ventral abdomen). The space 12 on the right-hand side. Gastroscopy carried out displacement was reduced and the large colon was exteriorised. On eighteen hours after admission showed the presence of multifocal visual examination the entire wall of the large colon was moderately ulcerations along the squamous epithelium of the margo plicatus congested and oedematous. Lesions restricted to the right dorsal and involving the dorsal region of the glandular mucosa.
colon included multifocal areas of congested serosa with irregularmural thickenings. The content of the large colon was removed via enterotomy at the pelvic flexure, after which the serosa of the large Analgesia was induced by the intravenous administration of colon improved in colour, except in the affected areas of the right 250mg xylazine (0.5mg/kg bwt) and 5mg butorphanol dorsal colon where the serosa remained congested and the bowel (0.01mg/kg bwt), which brought about immediate cessation of wall remained thickened. Despite these visible pathological changes, signs of abdominal discomfort. Fluid therapy was initiated with it was decided not to resect the affected portion but to treat RDC 10 litres of sterile balanced electrolyte solution (Hartmann's) medically. The abdomen was closed in a standard three-layer closure.
supplemented with 69g calcium borogluconate (140mg/kg The gelding made an uneventful recovery from anaesthesia, and was bwt). This was administered at maintenance rates of maintained postoperatively on 3.3g gentamicin (6.6mg/kg bwt) i.v.
3ml/kg/hour and continued for 24 hours. Trimethoprim s.i.d., 6g procaine penicillin (12mg/kg bwt) i.m. b.i.d., 4g sulphonamide 7.5g (15mg/kg bwt) was administered i.v. s.i.d.
pentoxyfilline (8mg/kg bwt) p.o. b.i.d., 15mg butorphanol for three days. Food was withheld for eighteen hours and (0.03mg/kg bwt) i.v. t.i.d. for the initial 24 hours postoperatively omeprazole paste was added to the therapy at a dose of 4mg/kg and 250g (0.5g/kg bwt) dimethylsulphoxide was administered i.v.
bwt. p.o. s.i.d. for fourteen days.
as a 5% solution s.i.d. Maintenance fluid therapy (1.5L/kg/hour)was continued for 48 hours. The gelding made an uncomplicated recovery from surgery and was discharged six days after admission.
While the gelding was in the hospital, rectal examinations did not Clinical pathology at this time showed a packed cell volume of reveal any abnormalities. The gelding did not experience any more 0.29L/L, total protein at 36g/L and albumin at 16g/L. Follow-up colic symptoms over the following 72 hours and was discharged from therapy consisted of box rest, dietary modification, continuation of the hospital. Follow-up therapy consisted of omeprazole paste psyllium and corn oil in the diet and avoidance of non-steroidal formulation 4mg/kg p.o. s.i.d., and the addition of psyllium mucilloid anti-inflammatory drugs. For the initial two months after discharge, (50g) and corn oil (200ml) to the diet twice daily. In order to the gelding experienced mild bouts of colic on average every two eliminate high bulk fibre from the diet, small quantities of fresh grass weeks, which were controllable with xylazine or detomidine and and pelleted feed were to be given at frequent intervals during the day.
butorphanol. Clinical pathology ten weeks after discharge showed The owner was also advised regarding the avoidance of NSAIDs.
packed cell volume of 0.32L/L, total protein at 43g/L and Volume 57 (8) : August, 2004Irish Veterinary Journal albumin at 20g/L. At the last update, twelve months after surgery, anastomosis was carried out. The abdomen was closed in a the gelding was competing successfully, and had not experienced standard three-layer closure. any noted abdominal discomfort in the latter nine months.
The mare made an uneventful recover y from anaesthesia.
Postoperative therapy included 3.3g gentamicin (6.6mg/kg bwt) i.v. s.i.d. for five days, 6g procaine penicillin (12mg/kg bwt) i.m.
History and clinical examination b.i.d. for seven days, 7.5 g metronidazole (15mg/kg bwt) p.o.
A 10-year-old mare was admitted to the hospital for investigation b.i.d. for five days, 15mg butorphanol (0.03mg/kg bwt) i.v. t.i.d.
and treatment of weight loss and intermittent bouts of acute colic for 24 hours, 4g pentoxyfilline (8mg/kg bwt) p.o. b.i.d. for five over a period of six months. Diarrhoea had been present for the days and 250gm dimethylsulphoxide (0.5gm/kg bwt) previous month. Seven months prior to presentation, administered i.v. as a 5 % solution s.i.d. for three days.
phenylbutazone was administered for a chronic lameness. The Maintenance i.v. fluids were provided for three days. Water was owner could not recall the exact dose; however, the duration of allowed p.o. 24 hours after surgery and small grass feeds were administration was at least three weeks. Results of the clinical introduced after 36 hours. The mare continued to make an examination are outlined in Table 2.
uneventful recovery from surgery and was discharged after 10days hospitalisation.
Further investigations Clinicopathological abnormalities included mild anaemia and leukopaenia with neutropaenia (Table 3). There was moderate Gross examination of the resected bowel revealed severe oedema hypoproteinaemia with marked hypoalbuminaemia and mild of the bowel wall with multiple haemorrhagic areas on the serosal hypocalcaemia. Faecal occult blood test was positive. Abdominal surface. There was marked congestion with severe diffuse ultrasonography showed a slight increase in the amount of free ulceration of the mucosa. Histopathology confirmed ulcerative peritoneal fluid and also a thickened right dorsal colon wall (1.2 foci in the mucosa, with fibronecrotic debris overlying some of cm). Abdominocentesis revealed a grossly normal sample, the ulcerated areas. There were infiltrating sheets of fibrous without abnormalities on analysis. connective tissue in the lamina propria. Initially, the diet was altered to remove high bulk fibre, and Four weeks after discharge the mare was reported to be doing frequent feeds of fresh grass and pelleted concentrate feeds were very well; she was still on box rest and being fed small and introduced. Forty-eight hours after presentation, the mare became frequent feeds. Haematology and biochemistry at this time restless with frequent attempts to roll. Clinical examination at this showed packed cell volume at 0.33L/L, total protein at 45g/L time revealed an elevated pulse of 84 beats/minute and an and albumin at 20g/L.
increased respirator y rate of 24 breaths/minute. Rectal Six weeks after discharge the mare developed severe colic and was examination at this time did not reveal any abnormality. PCV euthanised by the referring veterinarian. A postmor tem increased to 0.44L/L and total protein to 50g/L. Nasogastric examination was not carried out.
intubation did not yield gastric reflux. On intravenousadministration of 300mg xylazine (0.06mg/kg bwt) and 10mg Discussion
butorphanol (0.02mg/kg bwt) the colic symptoms resolved but The diagnoses of right dorsal colitis were based on the history of they recurred 15 minutes later. Due to the clinical findings and phenylbutazone administration, together with the clinical signs, the poor response to analgesia, an exploratory celiotomy was clinical pathology and ultrasonography. These findings allow for a presumptive diagnosis of RDC (Cohen et al., 1995a, b; Bueno et Preoperatively, the mare received 3.3g gentamicin (6.6mg/kg al., 2000; Cohen, 2002). The differential diagnoses for RDC bwt) i.v. and 6g procaine penicillin (12mg/kg bwt) i.m. Ten litres include gastric ulceration, inflammatory, neoplastic or parasitic of a sterile balanced electrolyte solution was administered rapidly bowel diseases, and hepatopathies. Each of the three horses was i.v. Anaesthesia and fluid therapy protocols were the same as for subjected to a comprehensive work-up with those differential diagnoses in mind. In horses 2 and 3 direct visualization of the The mare was placed in dorsal recumbency and a ventral affected colon at celiotomy enabled confirmation of the diagnosis celiotomy approach was performed. Abdominal exploration and exclusion of other possible causes of the clinical signs revealed the colon to be in the correct position. Once the entire exhibited by the animals. large colon was exteriorised, significant pathology was evident, Abdominal ultrasonography was used in the diagnosis of all three localised to the right dorsal colon. There was diffuse mural cases. The peripheral wall of the right dorsal colon can be oedema with multiple old and fresh haemorrhagic lesions on the visualized through the intercostal spaces 11 to 15 on the right- serosa. Due to the gross pathological changes, the affected hand side of the abdomen. The duodenum and the liver will be portion of the right dorsal colon was resected and an end-to-end in the dorsal plane with the ventral colon ventrally. The wall Volume 57 (8) : August, 2004 Irish Veterinary Journal should rarely exceed 0.4cm thickness (Reef, 1998). Mural Cohen, N.D., Carter, G.K., Mealey, R.H. and Taylor, T.S.
thickening up to 2.5cm has been recorded in RDC (Cohen (1995a). Medical management of right dorsal colitis in five 2002). The interpretation of the image is very dependent on the experience and skill of the operator. There is a high risk of false Veterinary Internal Medicine 9: 272-276.
negatives as only a small portion of the right dorsal colon is Cohen, N.D., Mealey, R.H., Chaffin, M.K. and Carter, G.K.
imaged. Mural thickenings were identified in horse 1 (1.3cm) (1995b). The recognition and medical management of right and in horse 3 (1.2cm) but not in horse 2 - this may represent a dorsal colitis in horses. Veterinary Medicine 90: 687-692.
false negative finding, since two weeks later RDC was confirmed Collins, L.G. and Tyler, D.E. (1984). Phenylbutazone toxicosis
by direct visual inspection during exploratory laparotomy. It was in the horse: a clinical study. Journal of the American Veterinary felt that the specific lesions on the right dorsal colon of this horse Medical Association 184: 699-703.
could not be attributed just to the displacement of the colon; Collins, L.G. and Tyler, D.E. (1985). Experimentally induced
given the history, clinical findings and clinical pathology, the phenylbutazone toxicosis in ponies: description of the syndrome lesions were more indicative of RDC. and its prevention with synthetic prostaglandin E . American Gastroscopy is recommended in suspected cases of RDC as Journal of Veterinary Research 46: 1605-1615.
gastric ulceration can occur concomitantly with RDC, as it did in horse 2. Faecal occult blood was present in all three horses.
cycloxygenase (COX-1) and inducable cycloxygenase (COX-2); Horse 1 and 3 had the faecal samples taken prior to rectal rationale for selective inhibition and progress to date. Medical examination; however, the sample from horse 2 was taken Research Review 16: 181–206.
following rectal examination. False positive results for occult Karcher, L.F., Dill, S.G., Anderson, W.I. and King, J.M.
blood may be obtained up to 24 hours following rectal (1990). Right dorsal colitis. Journal of Veterinar y Internal examination (Cohen, 2002). Medicine 4: 247– 253.
Hypoproteinaemia, hypoalbuminaemia, decreased total serum calcium and mild anaemia were present in all three horses.
phenylbutazone in ponies. American Journal of Veterinar y Peritoneal fluid analyses revealed increases in total protein and Research 44: 2277-2279.
the white blood cell count for horses 1 and 2 but these MacAllister, C.G., Morgan, S.J., Borne, A.T. and Pollet, R.A.
parameters were within normal ranges for horse 3. On admission, (1993). Comparison of the adverse effects of phenylbutazone, horse 1 was massively hypoalbuminaemic and also had diarrhoea.
flunixin meglumine and ketoprofen in horses. Journal of the Intravenous fluid therapy was administered at 1.5 times American Veterinary Medical Association 202: 71-77.
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(1983). Effects of large dose phenylbutazone administration to In all three cases treatment was initially medical, adhering to the horses. American Journal of Veterinary Research 44: 774-780.
four basic principles: avoidance of NSAIDs: avoidance of stress; Maitho, T.E., Lees, P. and Taylor, J.B. (1986). Absorption and
modification of diet; and use of specific medications. Our case pharmacokinetics of phenylbutazone in Welsh mountain ponies.
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