EQUINE VETERINARY EDUCATION / AE / APRIL 2006 89

Case Report Nonstrangulating small colon obstruction caused by a submucosal haematoma S. STAHEL*, C. B. RILEY, M. WICHTEL AND P.-Y. DAOUST† Departments of Health Management and † and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, Prince Edward Island C1A 4P3, Canada. Keywords: ; colic; small colon; haematoma; submucosa

Introduction This report describes a case of nonstrangulating obstruction resulting from a submucosal haematoma of Compared with other intestinal causes of equine colic, the small colon in a horse. disorders of the small colon are relatively uncommon (White 1990; Edwards 1992). One review of specific intestinal Case details disorders reported the prevalence of small colon and rectal diseases to be between 2.9 and 17.7% (Keller and Horney History 1985). More recent estimates reported a 3.5% incidence in all admitted cases (White 1990) to 4.2% incidence in An 11-year-old Morgan gelding was presented to the Atlantic undergoing celiotomy for colic (Edwards 1992). American Veterinary College Veterinary Teaching Hospital (VTH) with a miniature horses, Arabians and ponies are reported to be the 36 h history of colic. The gelding was administered breeds at greatest risk of developing small colon disorders drugs and vaccinated every 3 months; (pyrantel (Ragle et al. 1992; Edwards 1997). pamoate ~13 mg/kg bwt per os) had been given 38 days prior Submucosal haematomas of the small colon are to admission, and vaccination against rhinopneumonitis/herpes uncommon, with only a few cases having been reported in myeloencephalopathy (EHV-1 and -4), tetanus, equine influenza the last 20 years (Pearson and Waterman 1986; Dart et al. (types A1 and A2) and rabies 11 weeks prior to admission. 1992; Edwards 1992). Earlier reports found small colon Faecal output had initially been reduced and was absent haematomas in 0.4–2.4% of horses that underwent for 18 h prior to presentation. The horse’s heart rate did not celiotomy due to colic (Pearson et al. 1975; Speirs et al. exceed 48 beats/min over the 36 h period. A nasogastric tube 1981), and in 0.2% of horses examined for colic (Huskamp was placed twice by the referring during the 1982). One author reported a 0.67% prevalence of small course of the disease and failed to yield reflux. colon haematomas in horses referred for colic meglumine administered 3 times at 1.1 mg/kg bwt by the (Edwards 1992), but more recent retrospective and referring veterinarian, resulted in temporary analgesia; prospective studies have not reported cases of small colon however, the horse became uncomfortable again 8–9 h after haematomas within their study populations (Hillyer et al. each dose. No abnormal findings were identified on rectal 2002; Proudman et al. 2002). Affected horses in recent examination by the referring clinician at first visit. A second reports were, on average, 14 years of age (range 8–23 years; 24 h later resulted in a tentative diagnosis n = 7; age not documented in 4 cases) (Pearson and of pelvic flexure impaction. The horse was subsequently Waterman 1986; Dart et al. 1992; Edwards 1992). No gender referred to the VTH. or breed predisposition has been identified and the lesion has not been described previously in foals (Pearson et al. 1975; Clinical examination Speirs et al. 1981; Pearson and Waterman 1986; Adams et al. 1988; Dart et al. 1992; Edwards 1992; Vatistas et al. 1996; Upon presentation to the VTH, the horse was quiet and Cable et al. 1997). Haematomas of the equine depressed. was estimated to be ~5% have also been reported in the (determined by skin tenting) and borborygmi were reduced (Kobluk and Smith 1988; Jach and Allmeling 1990; Kopf in volume and infrequent, especially on the left side of the 1990) and (van Hoogmoed and Snyder 1996). abdomen. Rectal temperature and respiratory rate were 36.8°C and 12 breaths/min, respectively. Heart rate was *Author to whom correspondence should be addressed. 44 beats/min. The horse’s mucous membranes were pink, 90 EQUINE VETERINARY EDUCATION / AE / APRIL 2006

M

Fig 1: Intramural haematoma of the small colon. The haematoma is obstructing the whole intestinal lumen, making it impossible for faeces to pass through. Fig 2: Circular muscle layer and submucosa of the small colon. There is marked infiltration of inflammatory cells into the with capillary refill time <2 secs. On rectal examination, the muscle layer (M) and haemorrhage in the submucosa (top right pelvic flexure was impacted with ingesta. No other corner). H&E; bar = 100 µm. abnormalities were identified. Scant, dark and dry faeces were removed from the rectum. Abdominocentesis failed to Post mortem findings produce fluid. Haematology revealed an inflammatory leucogram characterised by a normal total leucocyte count Necropsy was performed 12 h following euthanasia. On gross (7.3 x 109/l; reference range [rr] 5.5–12.5 x 109/l), left shift examination, a haemorrhagic and congested area was found in (bands 0.36 x 109/l) and 1+ toxic change. Fibrinogen level the small colon 2 m proximal to the anus. On palpation, the was 4 g/l. Serum biochemistry analysis revealed a contents of the described area had a gelatinous consistency. A hypokalaemia (2.5 mmol/l; rr 3.0–5.0 mmol/l), large intramural haematoma, obstructing the entire small hypophosphataemia (0.82 mmol/l; rr 1.0–1.8 mmol/l), colonic lumen, was diagnosed on section (Fig 1). The hypomagnesaemia (0.64 mmol/l; rr 0.74–1.02 mmol/l), haematoma was approximately 17 cm long, 8 cm in diameter, hyperglycaemia (7.6 mmol/l; rr 3.6–5.6 mmol/l) and soft and poorly organised. Proximal to the obstruction, the γ elevated -glutamyltransferase (GGT) (40 u/l; rr 0–25 u/l). small colon was filled with firm faecal balls. The large colon was With the exception of the elevated GGT, those distended with a greater amount of soft ingesta than would be abnormalities were thought to be due to reduced dietary expected in a normal horse subjected to euthanasia. The intake and stress. Cholestasis was suspected based on the caecum and right dorsal colon were gas-distended. An 8 cm elevation of GGT in the presence of a normal sorbitol long portion of the mesocolon, adjacent to the small colon and dehydrogenase concentration. immediately proximal to the haematoma, was haemorrhagic. The affected segment of bowel and mesocolon was fixed in Treatment 10% formalin. Sections, 5 µm thick, were cut and stained with haematoxylin and eosin. Histology revealed extensive Lactated Ringer’s solution was administered through a haemorrhage in the mesocolon that extended into the 14 gauge catheter into the left jugular vein. The flow rate was submucosa of the small colon. Inflammatory cells (50% adjusted to replace the horse’s fluid deficit of 5% within 12 h. Following rehydration the rate of fluid administration and 50% mononuclear leucocytes), fibrin, was reduced to 90 ml/kg bwt/day. Analgesia was provided fibroblasts and new capillaries had infiltrated the tissues (flunixin meglumine 1.1 mg/kg bwt i.v. q. 24 h) and food (mesocolon, colonic circular and longitudinal muscle layers, and withheld. Over the next 36 h, the horse’s condition submucosa) within and at the periphery of the large areas of deteriorated. The painful episodes increased, response to clotted blood (Fig 2). Neovascularisation and fibroblasts were medication decreased and the heart rate prominent in the mesocolon, suggesting that the process was intermittently rose to 72 beats/min. No faeces had passed subacute (>5 days’ duration). Within the mesocolon there was since admission and borborygmi were still reduced in volume also and haemorrhage in the walls of a few small blood and infrequent. Findings on rectal examination at this time vessels. The vascular lesion was not associated with perivascular were supportive of a tentative diagnosis of large colon necrosis or haemorrhage. A portion of the intestinal mucosa at displacement. Passage of a nasogastric tube was attempted, the level of the haematoma had sloughed off, leaving only a but the tube could not be advanced into the stomach. Based thin layer of bacteria covering the submucosal surface. on the poor response to therapy, surgical exploration was The final post mortem diagnosis was focal, subacute recommended. The horse’s owner opted to subject the horse submucosal haematoma of the small colon with secondary to euthanasia. luminal obstruction. 92 EQUINE VETERINARY EDUCATION / AE / APRIL 2006

Discussion resulting in clinical signs. It is possible that the initial injury occured in the mesocolon (chronic changes were most Small colon haematomas have only been reported previously in prominent there) and that the colonic wall was secondarily mature horses (Pearson and Waterman 1986; Dart et al. 1992; affected. Gross findings suggested a localised disease process. Edwards 1992). Although foals may suffer from small colon However, histological evaluation of other grossly normal obstruction (Adams et al. 1988), submucosal haematomas sections of both small and large intestines should have been have not been described. This may suggest that small colon performed to rule out multifocal disease. submucosal haematomas are neither congenital nor In most reported cases of equine small colon haematomas, developmental, but rather that they are an acquired condition. the cause remains speculative. Equine strongyle disease has The duration of colic in horses with submucosal been postulated as a possible cause (Keller and Horney 1985). haematoma of the small colon reported in the history varies The larvae as well as the adult gastrointestinal may from 6 h to 5 days (Speirs et al. 1981; Pearson and Waterman cause direct intestinal wall damage. However, a multifocal 1986; Edwards 1992). In general, intestinal distention, lesion pattern is typical and the small colon is an atypical mesenteric tension and intestinal necrosis are considered location for these parasites (Keller and Horney 1985). In the responsible for pain (Mair 2002). In horses with submucosal present case, there were no gastrointestinal parasites detected haematoma of the small colon, expansion and necrosis of the grossly, eosinophils were absent, and hypobiotic larvae were small colon wall by the submucosal haemorrhage may be not seen. Because the small colon receives its blood supply responsible for pain. However, gas-distended intestine from the caudal mesenteric artery and, to a lesser extent, from proximal to the small colon obstruction, a characteristic the cranial mesenteric artery, thromboembolic ischaemia feature in all the horses described by Speirs et al. (1981), secondary to migrating Strongylus vulgaris larvae may also Pearson and Waterman (1986) and Edwards (1992), may also account for colonic injury. The haemorrhage in this horse may be a contributing factor to the development of intestinal pain. have originated in the mesocolon. Therefore, it is possible that It is possible that horses with a more chronic history of colic verminous thromboemboli initiated the bleeding; however, experience slower or only partially obstructing submucosal there was no evidence of verminous arteritis in this case. haemorrhage compared to horses with peracute colic onset. In If equine strongyle disease is a possible cause for small the current case the onset of colic was subacute. The authors colon haematoma, improved anthelmintic strategies and hypothesise that the pain experienced resulted from 3 factors: development of the anthelmintic drug group of avermectins generalised gas distention of the , local may explain why there has been a general decrease in reports distention of the small colon at the site of the haematoma, of small colon haematomas in recent years (Hillyer et al. 2002; and necrosis of the mesocolon. Proudman et al. 2002). The aetiology of submucosal haemorrhage has been Iatrogenic rectal trauma has been hypothesised as a cause discovered in two previously reported cases (Speirs et al. (Speirs et al. 1981; Pearson and Waterman 1986), but the 1981). One horse showed chronic ulceration of the small lesion in our case was 2 m proximal to the anus. Transrectal colon mucosa, which affected the submucosa and trauma would have to be expected in order to initiate the consequently resulted in submucosal bleeding. The other lesion diagnosed in the present case. A rectal lesion was not horse suffered from iatrogenic rectal trauma, which resulted in found. Furthermore, the problem appeared to be at least submucosal bleeding of the small colon. Histological 5 days old and there was no history of rectal palpation prior to evaluation was important in establishing the aetiology in the examination by the referring clinician. first case. Speirs et al. (1981) discovered focal ulceration of the Chronic mucosal ulceration with subsequent severe mucosa, severe cellulitis and damaged blood vessels in the cellulitis of the submucosa and damage to its vasculature has submucosa and concluded that ulceration of the mucosa had been implicated as a cause of submucosal bleeding (Speirs led to cellulitis, which consequently damaged blood vessels in et al. 1981). In our horse, there was histological evidence of the submucosa. In other reports (Speirs et al. 1981; Pearson mucosal sloughing in the area of the submucosal haematoma. and Waterman 1986; Edwards 1992), histology has been only However, this focal mucosal loss was determined to be casually mentioned or not performed. Careful histological a preterminal change, supported by the lack of submucosal evaluation of the lesion site is a useful method of detecting infiltration with inflammatory cells. In addition, the aetiology of small colon submucosal haematomas. In the gastrointestinal parasites and nonsteroidal anti-inflammatory present case, histological evaluation revealed haemorrhage drugs (NSAIDs), 2 common causes of mucosal ulceration, and in the wall of the small colon as well as in could not be identified as causal agents in this horse. the adjacent mesocolon. Neovascularisation and fibroplasia Parasitism was ruled out on gross examination of the small were particularly marked in the mesocolon. The fibroblastic and large intestine and histologically in the region of the phase of intestinal healing commences ~5 days after injury lesion, and NSAIDs were not administered until 2 days before (Robertson 1990). The histological appearance in this case the horse was subjected to euthanasia. suggests that the lesion was older than indicated by the time In man, blunt trauma has been implicated as a cause of of onset of clinical signs. The haematoma as it appeared at the intestinal (, jejunum) intramural haematoma time of necropsy was focal, but unorganised, and may have formation, due to the fact that the duodenum and proximal expanded suddenly only a few days prior to presentation, portion of jejunum are positioned adjacent to the spine (Bailey EQUINE VETERINARY EDUCATION / AE / APRIL 2006 93

and Akers 1965; Morson and Dawson 1972). In horses, blunt to shortness of the mesocolon (Edwards 1997). In those trauma is an unlikely cause of intestinal intramural cases, either resection of the affected part of the small colon haematoma formation, as their intestines are not fixed as must be performed within the abdominal cavity or colostomy closely to the spine. There was also no history of trauma in this may be necessary. case. To date there are no data to support the aetiology of In the process of working up a case with submucosal blunt trauma in cases of equine small colon haematoma. haematoma of the small colon, differential diagnoses should Haemorrhagic bowel syndrome (HBS) has been described in include large colon disorders such as feed impaction, dairy cattle (Dennison et al. 2002). Features include severe displacement and partial torsion, as well as several diseases of necrohaemorrhagic or jejunitis with intraluminal the small colon (, foreign body obstruction, faecal haemorrhage or blood clots. The most prominent histological impaction, faecaliths, phytoconglobates and bezoars). Although findings are severe segmental submucosal haemorrhage and rare, submucosal haematoma of the small colon should also be oedema of the . For a large percentage of included in the list of differential diagnoses for colic. affected cattle, faecal cultures were positive for perfringens. There was no histological evidence of an infestation Conclusions with Clostridium spp. in the present case. A more multifocal disease pattern would be considered more typical of clostridial Submucosal haematoma of the small colon is a rare cause of infection, and this was not observed in the present case. colic in the horse. Ante mortem diagnosis and treatment The presence of a small colon submucosal haematoma require exploratory surgery of the abdomen. Based on the was not detected ante mortem in this case. Nonsurgical ante literature, submucosal haematomas of the small colon have a mortem diagnosis of this condition is challenging. Transrectal reasonable to good prognosis when managed surgically. The palpation of a gelatinous mass in the small colon may be aetiology of submucosal bleeding of the small colon remains possible; however, the clinician would have to be fortunate to speculative. Further histological studies in horses with small find the focal lesion and interpret its significance. In only 2 of colon haematomas are needed to understand the aetiology of 7 cases of small colon haematoma discussed thoroughly in the the disease. literature was a hard mass discovered on rectal palpation (Speirs et al. 1981; Pearson and Waterman 1986). In neither of References these cases was the location of the mass determined, or a specific diagnosis made based on rectal findings. In 2 other Adams, R., Koterba, A.M., Brown, M.P., Cudd, T.C. and Baker, W.A. (1988) Exploratory celiotomy for gastrointestinal disease in cases, blood was discovered on the sleeve after rectal neonatal foals: a review of 20 cases. Equine vet. J. 20, 9-12. palpation, suggesting that the intestinal mucosa may rupture Bailey, W.C. and Akers, D.R. (1965) Traumatic intramural hematoma and bleed into the intestinal lumen. Hence (clotted) blood of the duodenum in children: a report of 5 cases. Am. J. Surg. 110, discovered on rectal examination may be of diagnostic value, 695-703. but must be differentiated from blood resulting from rectal Cable, C.S., Fubini, S.L., Erb, H.N. and Hakes J.E. (1997) Abdominal tear. A common rectal finding in cases reported with surgery in foals: a review of 119 cases (1977-1994). Equine vet. J. submucosal haematoma of the small colon is tympany of the 29, 257-261. large intestine (Speirs et al. 1981; Pearson and Waterman Dart, A.J., Snyder, J.R. and Pascoe, J.R. (1992) Resection and 1986; Edwards 1992). This is a nonspecific finding which may of the small colon in four horses. Aust. vet. J. be present in numerous causes of intestinal blockage, and 69, 5-7. therefore is not diagnostic per se. Tympany of the large Dennison, A.C., VanMetre, D.C., Callan, R.J., Dinsmore, P., Mason, G.L. and Ellis, R.P. (2002) Hemorrhagic bowel syndrome in dairy intestine was not a prominent feature of the present case. cattle: 22 cases (1997-2000). J. Am. vet. med. Ass. 221, 686-689. Transrectal ultrasonography may be beneficial in Edwards, G.B. (1992) A review of 38 cases of small colon obstruction diagnosing strangulating lesions of the small colon (Freeman in the horse. Equine vet. J., Suppl. 13, 42-50. et al. 2001; Schumacher and Mair 2002; Freeman 2002); Edwards, G.B. (1997) Diseases and surgery of the small colon. Vet. however, it seems to be of limited use in the case of intramural Clin. N. Am.: Equine Pract. 13, 359-375. haematomas. The difficulty lies in finding the affected Freeman, S. (2002) Ultrasonography of the equine abdomen: segment of the small colon and positioning the ultrasound techniques and normal findings. In Pract. 24, 204-211. probe correctly in order to produce a diagnostic picture. Freeman, S.L., Boswell, J.C. and Smith, R.K.W. (2001) Use of Exploratory surgery seems to be the most definitive transrectal ultrasonography to aid diagnosis of small colon diagnostic tool. Surgical removal of the affected small colon strangulation in two horses. Vet. Rec. 148, 812-813. segment is the only recommended treatment option for these Hillyer, M.H., Taylor, F.G.R., Proudman, C.J., Edwards, G.B., Smith, J.E. cases (Pearson et al. 1975; Speirs et al. 1981; Pearson and and French, N.P. (2002) Case control study to identify risk factors for simple colonic obstruction and distension colic in horses. Waterman 1986; Edwards 1992, 1997; Moore 1990; Equine vet. J. 34, 455-463. Schumacher 2002). Based on previous reports, small colon Huskamp, B. (1982) The diagnosis and treatment of acute abdominal haematomas have a fair to good prognosis when managed conditions in the horse. In: Proceedings of the 1st Equine Colic surgically. Prognosis decreases if the haematoma is situated in Research Symposium, University of Georgia, USA. pp 261-272. either the origin or the distal end of the small colon. These Jach, T. and Allmeling, G. (1990) Obturationsileus des Jejunums bei two segments of the small colon cannot be exteriorised due einer Traberstute aufgrund eines submukoesen Haematoms, 94 EQUINE VETERINARY EDUCATION / AE / APRIL 2006

hervorgerufen durch Massenbefall mit Anoplocephala perfoliata. Proudman, C.J., Smith, J.E., Edwards, G.B. and French, N.P. (2002) Pferdeheilkunde 6, 89-92. Long-term survival of equine surgical colic cases. Part 1: Patterns Keller, S.D. and Horney, F.D. (1985) Diseases of the equine small colon. of mortality and morbidity. Equine vet. J. 34, 432-437. Comp. cont. Educ. pract. Vet. 7, 113-120. Ragle, C.A., Snyder, J.R., Meagher, D.M. and Honnas, C.M. (1992) Kobluk, C.N. and Smith D.F. (1988) Intramural hematoma in the Surgical treatment of colic in American miniature horses: 15 cases jejunum of a mare. J. Am. vet. med. Ass. 192, 379-380. (1980-1987). J. Am. vet. med. Ass. 201, 329-331. Kopf, N. (1990) Protrahierte Magenruptur infolge eines Robertson, J.T. (1990) Intestinal enterotomy, resection, and Duenndarmileus und intramurales Haematom des Jejunums in anastomosis. In: The Equine , Ed: N.A. White, Lea Verbindung mit Zestodenbefall bei einem Pferd. Pferdeheilkunde & Febiger, Philadelphia. pp 251-276. 6, 169-171. Schumacher, J. (2002) Diseases of the small colon and rectum. In: Mair, T. (2002) Clinical evaluation of the colic case: clinical signs of Manual of Equine , Eds: T. Mair, T. Divers and N. colic. In: Manual of Equine Gastroenterology, Eds: T. Mair, T. Divers Ducharme, W.B. Saunders Co., London. pp 299-315. and N. Ducharme, W.B. Saunders Co., London. pp 107-109. Schumacher, J. and Mair, T.S. (2002) Small colon obstructions in the Moore, J.N. (1990) Diseases of the small colon and rectum. In: The mature horse. Equine vet. Educ. 14, 19-28. Equine Acute Abdomen, Ed: N.A. White, Lea & Febiger, Speirs, V.C., van Veenendaal, J.C., Christie, B.A., Lavelle, R.B. and Gay, Philadelphia. pp 392-402. C.C. (1981) Obstruction of the small colon by intramural Morson, B.C. and Dawson, I.M.P. (1972) Tumour-like lesions of the haematoma in three horses. Aust. vet. J. 57, 88-90. small intestine. In: Gastrointestinal Pathology, 2nd edn., Blackwell van Hoogmoed, L. and Snyder, J.R. (1996) Acute small intestinal injury Scientific Publications Ltd, Oxford. p 394. associated with hematomas in the mesentery of four horses. J. Pearson, H. and Waterman, A.E. (1986) Submucosal haematoma as a Am. vet. med. Ass. 209, 1453-1456. cause of obstruction of the small colon in the horse: a review of Vatistas, N.J., Snyder, J.R., Wilson, W.D., Drake, C. and Hildebrand, S. four cases. Equine vet. J. 18, 340-341. (1996) Surgical treatment for colic in the foal. Equine vet. J. 28, Pearson, H., Pinsent, P. J.N., Denny, H.R. and Waterman, A. (1975) The 139-145. indications for equine laparotomy - an analysis of 140 cases. White, N.A. (Ed) (1990) Epidemiology and etiology of colic. In: The Equine vet. J. 7, 131-136. Equine Acute Abdomen, Lea & Febiger, Philadelphia. pp 49-64.

Clinical Commentary Potential causes and alternate methods for diagnosis and treatment of small colon submucosal haematoma: can we extrapolate from human patients? L. L. SOUTHWOOD University of Pennsylvania, New Bolton Center, 382 W. Street Rd, Kennett Square, Pennsylvania, USA.

Intestinal obstruction resulting from submucosal haematoma (TerKonda et al. 1992), of 274 cases only 12 involved the colon, formation is an uncommon cause of in with no cases involving the rectum (Hughes et al. 1977). horses. The sequence of events leading up to the formation Interestingly, the large intestine is thought to be less commonly of a submucosal haematoma is usually undetermined. affected, because the taenia coli play a protective role against Possible aetiologies in the case reported above (Stahel et al. initiation and expansion of the haematoma (Abbas et al. 2006) are straining to defaecate in association with a primary 2002a,b). Common causes of gastrointestinal tract submucosal small colon impaction, faecalith or dried faeces; trauma haematomas in human patients include blunt abdominal associated with passage of a foreign body; or external trauma, anticoagulant therapy (particularly warfarin toxicity), abdominal wall trauma. coagulopathy (for example, idiopathic thrombocytopaenia, In human patients, gastrointestinal submucosal haematoma haemophilia), pancreatic disease, alcoholism, malignancy (for formation is also uncommon. While submucosal haematomas example, leukaemia, , myeloma), inflammatory and can occur at various regions of the gastrointestinal tract, immune-mediated disease (for example, vasculitis), including the oesophagus (Kise et al. 2001; Ganeshram and chemotherapy and bone transplantation, and in some cases the Harrison 2002), duodenum (Hughes et al. 1977), jejunum (Birns cause is unknown (Birns et al. 1979; Kise et al. 2001). Many et al. 1979), sigmoid colon (Yoshida et al. 1983) and rectum cases of gastrointestinal submucosal haematoma formation in 96 EQUINE VETERINARY EDUCATION / AE / APRIL 2006

man occur in the older (over 60 years) population (Ganeshram Most human patients present with acute and severe and Harrisson 2002; Polat et al. 2003), probably as a abdominal, thoracic or (Abbas et al. 2002a) and consequence of a higher incidence of underlying disease. gastrointestinal tract obstruction (TerKonda et al. 1992). Whether the horse in the accompanying report had an Pain is thought to be associated with epithelial separation underlying disease is unknown, but it appears unlikely. by the submucosal haematoma (Kise et al. 2001) and In human patients, submucosal haematoma of the obstruction (Yoshida et al. 1983). Abdominal pain is a oesophagus and Mallory-Weiss tears (mucosal injury) occur nonspecific sign in human and veterinary patients and following retching and , and can also occur with additional diagnostic tests are required. In equine patients coughing, blunt trauma, childbirth and during an epileptic fit with abdominal pain, routine diagnostic tests are limited to (Kise et al. 2001). A close temporal relationship with food physical examination, passage of a nasogastric tube, rectal intake has also been reported (Ganeshram and Harrisson palpation, haematology and serum biochemistry, and 2002). It is proposed that haematoma formation occurs peritoneal fluid analysis. Exploratory celiotomy is performed secondarily to a sudden increase in intraluminal pressure (Kise as a diagnostic and therapeutic procedure in horses that do et al. 2001). A spontaneous rectal haematoma was diagnosed not respond to medical therapy, if economics permit. While in a 17-year-old human patient following a history of chronic advanced diagnostic procedures are generally not constipation and straining to defaecate (TerKonda et al. 1992). performed routinely on horses with abdominal pain, That patient was receiving warfarin therapy and had a because horses respond to medical management, undergo prolonged prothrombin time. The haemorrhage is usually in the exploratory celiotomy or are subjected to euthanasia, it is submucosa of the intestine and originates from a small vessel important, even in retrospect, to consider alternative producing slow bleeding (Abbas et al. 2002a,b). As in the case diagnostic procedures and treatments. The diagnosis of reported by Stahel et al. (2006), intraluminal, intramesenteric, submucosal haematoma formation is more readily made in and retroperitoneal haemorrhage can also occur (Abbas et al. human patients based on a history of trauma, coagulopathy, 2002a,b); the horse in this case may have been straining to anticoagulant use or underlying disease in combination with defaecate against a small colon impaction or faecalith, for various diagnostic tests. example, and the submucosal haematoma occurred as a result Other diagnostic procedures to consider include faecal of straining, with secondary development or exacerbation of occult blood, transabdominal or transrectal ultrasound the small colon impaction. examination, colonoscopy and diagnostic . Blunt abdominal trauma is also a feasible, although less Peritoneal fluid analysis and measurement of faecal occult probable, cause of small colon haematoma formation in this blood could have been performed in the case reported. case. In human patients, the abdominal trauma may be major Peritoneal fluid analysis may have revealed serosanguinous or minor and ‘all but forgotten by the patient’ (Hughes et al. fluid. In a study of human patients reporting on small 1977). The majority of gastrointestinal tract haematomas intestinal submucosal haematomas, approximately 30% of resulting from blunt trauma in human patients occur in young cases were associated with gastrointestinal haemorrhage children (less than 10 years), and this is thought to be because (Birns et al. 1979) and a faecal occult blood may have been of their less developed abdominal musculature (Hughes et al. positive (Polat et al. 2003). The ultrasonographic appearance 1977). Submucosal haematoma formation resulting from of acute submucosal haematomas may be nonspecific (Abbas abdominal trauma in human patients most often occurs in the et al. 2002b) and reveals intestinal wall thickening and free duodenum because of its fixed position (Hughes et al. 1977). fluid within the peritoneal cavity (Polat et al. 2003). Haematoma formation is thought to occur as a result of Ultrasound examination successfully diagnosed 5 out shearing of the layers of the intestinal wall causing tearing of of 7 human patients with haematomas involving the the submucosal vessels (Hughes et al. 1977). With the well gastrointestinal tract (Polat et al. 2003) and has also been used developed equine abdominal musculature, it seems unlikely to aid in the diagnosis of a rectal haematoma (Babu et al. that blunt abdominal trauma, particularly minor trauma 2001). Ultrasonographic evaluation is being used more without other signs, would be a common cause of small colon routinely in horses with abdominal pain. The small colon can submucosal haematoma. Additionally, if blunt abdominal be seen ultrasonographically in the left caudodorsal quadrant trauma was a likely cause of submucosal haematoma dorsal to the pelvic flexure (Desrochers 2005). The success of formation in horses, we would expect to see this type of lesion ultrasound examination to diagnose the small colon commonly with the type of activities in which horses routinely submucosal haematoma depends on the proximity of the engage, and this does not appear to be the case. small colon to the rectum or body wall. Fifty percent of major haemorrhagic problems of the Endoscopy has been used for diagnosis of oesophageal gastrointestinal tract in human patients are associated with (Kise et al. 2001; Ganeshram and Harris 2002; Nagai et al. colonic cancer, ulceration, diverticula disease and hiatus 2004) and rectal (TerKonda et al. 1992; Babu et al. 2001) (Moseley et al. 1963). While most of these conditions are submucosal haematomasin human patients. Colonoscopy unlikely to be important causes in horses, neoplasia should using a 3 m endoscope could have been performed to always be considered in a horse with submucosal identify a lesion 2 m oral to the rectum. Endoscopically, the haemorrhage and a sample of the affected intestine submitted haematoma may be identified as a large dark red or purple- for histological evaluation. red superficial smooth swelling (Nagai et al. 2004). However, EQUINE VETERINARY EDUCATION / AE / APRIL 2006 97

without histological evaluation, a definitive diagnosis could through a serosal incision or by resection and anastomosis, be difficult to make in horses based on the gross appearance with a good outcome using either technique (Moore and of the lesion alone. Carpenter 1984). A 71-year-old human patient with a large Laparoscopy is being used more often as a diagnostic, and rectal haematoma was treated by transanal incision and occasionally therapeutic, modality in horses with abdominal drainage of the haematoma (Babu et al. 2001). If the pain. It can be performed under standing sedation or general haematoma was not accessible, a temporary colostomy could anaesthesia in dorsal recumbency. The small colon lesion could be performed to divert faeces from the small colon to allow have been identified laparoscopically and a biopsy obtained the haematoma to resolve and small colon to heal (Yoshida et and/or the haematoma evacuated. Resolution of the small al. 1983; Freeman and Martin 1992; TerKonda et al. 1992). colon impaction would require medical management or The colostomy could be reversed within 10–21 days following surgical intervention. Laparoscopic cannula insertion, resolution of the lesion (Freeman and Martin 1992). however, may be challenging in patients with severe Alternatively, the small and large colon oral to the haematoma abdominal distention and large intestinal decompression could be evacuated of feed via an enterotomy and the horse (trocharisation) may be necessary prior to making a given or a low residue or liquid diet to laparoscopic approach. Alternatively, in cases in which allow the affected area to rest. economics are a concern, a flank approach to the abdomen In human patients, gastrointestinal submucosal could be used to access the small colon for diagnostic and haematomas often resolve spontaneously within days to weeks therapeutic purposes (Hardy 2003a). with medical management (fasting, parenteral nutrition, Unfortunately, because of the large size of the equine antimicrobial drugs) and surgical intervention is generally not adult abdomen, many imaging modalities used in human recommended for spontaneous haematoma formation, patients cannot be applied to horses. Radiography can be particularly if it is secondary to anticoagulant toxicity or performed in human patients and the addition of barium coagulopathy (Birns et al. 1979; TerKonda et al. 1992; Kise et contrast is particularly successful in obtaining a diagnosis of al. 2001; Abbas et al. 2002a,b; Ganeshram and Harisson 2002; submucosal haematoma (Hughes et al. 1977; Yoshida et al. Polat et al. 2003; Nagai et al. 2004). However, acute severe 1983; Babu et al. 2001). Some of the typical findings of a intestinal obstruction, particularly associated with trauma, barium contrast study in patients with submucosal requires surgical intervention. Human patients with haematoma formation include a ‘picket fence’ or ‘stacked spontaneous intramural small intestinal haematoma secondary coin’ appearance of the small intestine (thickened to either anticoagulant toxicity or coagulopathy were treated oedematous mucosal folds with spike-like projections of medically with nasogastric decompression for an average of barium) or ‘coiled spring’ appearance (intussusception of the 4 days (0–13 days) (Abbas et al. 2002a). Most patients resumed mucosa with oedema distal to the haematoma) (Hughes et al. feeding after 4 days and 11 out of 13 patients survived to 1977; Babu et al. 2001). A barium has been used to discharge. These authors concluded that while in the past aid in the diagnosis and evaluation of sigmoid colon (Yoshida exploratory laparotomy, evacuation of the haematoma, et al. 1983; Polat et al. 2003) or rectal (TerKonda et al. 1992) resection or intestinal bypass was important, most patients submucosal haematomas and barium swallow for improve with nonsurgical management (Abbas et al. 2002a). oesophageal submucosal haematomas (Ganeshram and There were no short- or long-term complications associated Harrisson 2002). In human patients, plain and contrast- with resolution of the haematoma (Abbas et al. 2002a). enhanced computerised tomography (CT) can provide early Options for medical management in horses involve and accurate diagnosis of small intestinal haematomas withholding feed and oral treatment with laxatives, water (TerKonda et al. 1992; Abbas et al. 2002a,b); however, CT was and electrolytes, i.v. polyionic isotonic fluids to maintain not able to detect an ascending colon intramural haematoma hydration, and analgesia. Parenteral nutrition should also be in one patient that was subsequently diagnosed with considered (Hardy 2003a). The importance of oral fluids for ultrasound examination (Polat et al. 2003). This useful imaging hydrating ingesta has recently been demonstrated modality is currently not available for the equine abdomen. experimentally (Lopes et al. 2004). The right dorsal colon and Surgical exploration would probably have been necessary faecal water content was higher in horses given oral in the case reported by Stahel et al. (2006) to obtain a compared with i.v. fluids and electrolytes (Lopes et al. 2004). definitive diagnosis. If the affected segment of intestine was Specifically, horses treated with a balanced electrolyte readily accessible via a ventral midline celiotomy then a solution per os had an optimal compromise between resection and anastomosis, with submission of the resected hydration of ingesta/faeces and maintenance of systemic intestine for histological evaluation, would be recommended. electrolyte balance (Lopes et al. 2004). Additionally, if there is an area of necrosis, resection of the The diagnosis and treatment of submucosal haematomas is affected segment and anastomosis is indicated (Polat et al. challenging and an intramural mass should be considered in 2003). An alternative surgical approach to resection and any horse with an impaction that recurs or does not respond to anastomosis involves incising the serosa overlying the medical management. Economics play a considerable role in haematoma and evacuation of the haematoma (Hughes et al. diagnostic and treatment strategies in equine patients and, as 1977). In dogs, intramural haematomas of the duodenum and with the case presented by Stahel et al. (2006), many animals jejunum were treated surgically by evacuating the haematoma with abdominal pain are subjected to euthanasia without 98 EQUINE VETERINARY EDUCATION / AE / APRIL 2006

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