IMAGING DIAGNOSIS - RADIOGRAPHY, ULTRASONOGRAPHY, AND COMPUTED TOMOGRAPHY OF A GIANT FECALOMA CAUSING STERCORAL PERFORATION OF THE COLON IN A DOG WITH A PROSTATIC ABSCESS.

A mixed-breed dog presented with tenesmus, hematochezia, and abdominal distension of 2 weeks duration. Radiography showed a large round mass with a "soap-bubble" appearance and shell-like mineralization in the caudal abdomen. Computed tomography revealed a lamellate mineralized mass 8 cm in diameter and containing air in the descending colon and prostatic abscess. Heterogeneously contrast-enhanced, irregularly thickened colonic wall with intramural and peritoneal free gas indicated stercoral colonic perforation. Surgical intervention revealed a tumor-like giant fecaloma in the descending colon adjoining the prostate with extensive wall rupture and fecal peritonitis. Hypothetically, prostatic inflammation may affect colonic motility with resultant fecaloma formation.

Outcome of Surgical and Medical Management of Cecal Impaction in 150 Horses (1991-2011).

OBJECTIVE: To evaluate short- and long-term outcome after medical and surgical management of horses with cecal impaction and to determine reasons for death or euthanasia. STUDY DESIGN: Retrospective case series. ANIMALS: Horses (n = 150). METHODS: Data collected from medical records (1991-2011) of horses with a diagnosis of cecal impaction, included signalment, history of recent disease/surgical procedure, admission data, management (medical, typhlotomy alone, jejunocolostomy), complications, and outcome. Short-term outcome (alive or dead at discharge) and long-term outcome (alive or dead at ≥1 year) were determined by telephone interview. Data were analyzed using a χ(2) or Fisher's exact test. Level of significance was P < .05. RESULTS: Of 150 horses hospitalized with a diagnosis of cecal impaction, 102 (68%) had a history of recent disease or a surgical procedure. Thirty-eight horses (25%) had cecal perforation at admission and 3 horses (2%) were euthanatized without treatment. Of 109 horses treated, 59 (54%) were managed medically and 50 (46%) surgically (typhlotomy [26]; jejunocolostomy [24]). The proportion of horses alive at hospital discharge was significantly lower for horses managed medically (61%) compared with surgically (82%; P = .02) but there was no difference between horses managed with typhlotomy alone (77%) or with jejunocolostomy (88%; P = .47). There were 57% of horses managed medically alive at 1 year. There was a similar proportion of horses alive at 1 year after typhlotomy alone (73%) and jejunocolostomy (70%; P = .86). CONCLUSIONS: Compared to the recent reports, the proportion of horses alive at hospital discharge was lower for both medically and surgically managed horses with cecal impaction. There was decreased survival for horses treated medically than those treated surgically; however, no significant difference was seen in survival between horses managed with typhlotomy alone versus jejunocolostomy.

Prospective survey of veterinary practitioners' primary assessment of equine colic: clinical features, diagnoses, and treatment of 120 cases of large colon impaction.

BACKGROUND: Large colon impactions are a common cause of colic in the horse. There are no scientific reports on the clinical presentation, diagnostic tests and treatments used in first opinion practice for large colon impaction cases. The aim of this study was to describe the presentation, diagnostic approach and treatment at the primary assessment of horses with large colon impactions. METHODS: Data were collected prospectively from veterinary practitioners on the primary assessment of equine colic cases over a 12 month period. Inclusion criteria were a diagnosis of primary large colon impaction and positive findings on rectal examination. Data recorded for each case included history, signalment, clinical and diagnostic findings, treatment on primary assessment and final case outcome. Case outcomes were categorised into three groups: simple medical (resolved with single treatment), complicated medical (resolved with multiple medical treatments) and critical (required surgery, were euthanased or died). Univariable analysis using one-way ANOVA and Tukey's post-hoc test, Kruskal Wallis with Dunn's post-hoc test and Chi squared analysis were used to compare between different outcome categories. RESULTS: 1032 colic cases were submitted by veterinary practitioners: 120 cases met the inclusion criteria for large colon impaction. Fifty three percent of cases were categorised as simple medical, 36.6% as complicated medical, and 9.2% as critical. Most cases (42.1%) occurred during the winter. Fifty nine percent of horses had had a recent change in management, 43% of horses were not ridden, and 12.5% had a recent / current musculoskeletal injury. Mean heart rate was 43 bpm (range 26-88) and most cases showed mild signs of pain (67.5%) and reduced gut sounds (76%). Heart rate was significantly increased and gut sounds significantly decreased in critical compared to simple medical cases (p<0.05). Fifty different treatment combinations were used, with NSAIDs (93%) and oral fluids (71%) being administered most often. CONCLUSIONS: Large colon impactions typically presented with mild signs of colic; heart rate and gut sounds were the most useful parameters to distinguish between simple and critical cases at the primary assessment. The findings of seasonal incidence and associated management factors are consistent with other studies. Veterinary practitioners currently use a wide range of different treatment combinations for large colon impactions.

Constipation associated with brumation? Intestinal obstruction caused by a fecalith in a wild red diamond rattlesnake (Crotalus ruber).

This report describes the fecalith-induced intestinal obstruction of a free-ranging red diamond rattlesnake (Crotalus ruber) and the snake's subsequent history following surgical removal of the fecalith. The captured snake exhibited an abnormally distended abdomen and an extremely hard mass, detected via palpation, near its vent. Coeliotomy yielded a 2.5-cm, 5-g fecalith from the large intestine. Microscopic dissection of the fecalith revealed no evidence of gastrointestinal parasitic worms. Subsequently, we implanted a radio-transmitter that allowed us to track the snake's movements for 7 months (until the radio signal vanished), indicating normal behaviour, complete recovery and good health apart from the obstruction. This observation suggests that fecalith development and intestinal obstruction represent potential risks of long-term faecal retention, an unusual physiological trait well documented among rattlesnakes and other stout, heavy-bodied terrestrial viperid snakes. Dehydration and decreased gut motility associated with brumation (≈hibernation) may predispose temperate snakes to fecalith formation. Regional drought and a small mammal diet with indigestible hairs might have also promoted fecalith formation in this specimen.

Ponies, miniatures, and younger equids are at higher risk of fecalith obstruction compared to a general colic population.

OBJECTIVE: To determine breed, age, and sex predispositions for fecalith obstruction and to evaluate short-term survival and prognostic factors following surgical treatment of fecalith intestinal obstruction in equids. ANIMALS: 151 equids. METHODS: Medical records of equids undergoing surgery for fecalith obstruction from 2000 to 2020 were reviewed. Signalment, history, presenting clinicopathological data, surgical findings, complications, and short-term survival were recorded and compared between survivors and nonsurvivors. Signalment of the fecalith population was compared to a contemporaneous colic population. Clinical factors were assessed for association with outcome. RESULTS: 64 females, 53 castrated males, and 31 intact males were included. Three equids presented twice. Miniature horses, ponies, and miniature donkeys/mules represented 48% (71/148) of fecalith population and full-sized breeds represented 52% (77/148). Miniature horses and ponies were overrepresented and equids ≤ 1 year of age were overrepresented in the fecalith population compared to the colic population. One hundred thirty-nine equids (92%) survived to discharge, 6% (9/148) were euthanized intraoperatively, and 2% (3/148) were euthanized during hospitalization. Nonsurvivors showed more severe colic signs on admission, tachycardia on admission, and hyperlipemia. Equids with postoperative colic (P = .01) and complications (P = .002) were less likely to survive. CLINICAL RELEVANCE: Miniature horses and ponies were overrepresented compared to the colic population; however, full-sized breeds were also affected. Surgical treatment had an excellent short-term prognosis. Severe colic signs, tachycardia, hyperlipemia, postoperative colic, and surgical complications negatively affected short-term survival.

Subclinical cecal impaction in a dog.

A 7-year-old, bichon frise dog was incidentally diagnosed with cecal impaction. Typhlectomy was performed as cecal rupture and resultant septic peritonitis appeared to be imminent. Histopathological evaluation did not identify an underlying cause for impaction and cecal dysmotility was suspected. Subclinical cecal impaction has not previously been reported in dogs.

Impaction cæcale subclinique chez un chien. Un diagnostic fortuit d'impaction cæcale a été posé chez un chien Bichon frisé âgé de 7 ans. Une typhlectomie a été réalisée, car une rupture cæcale et une péritonite septique résultante semblaient imminentes. L'évaluation histopathologique n'a pas identifié une cause sous-jacente pour l'impaction et la dysmotilité était soupçonnée. L'impaction cæcale subclinique n'a pas été précédemment signalée chez les chiens.(Traduit par Isabelle Vallières).

Ileal impaction and jejunal enterotomy in a 4-month-old Arabian filly.

A 4-month-old Arabian filly was treated by surgical correction of an ileal impaction. The impaction was resolved through a distal jejunal enterotomy. One-year follow-up showed no post-operative complications secondary to the enterotomy. Jejunal enterotomy may be a surgical option for resolution of an ileal impaction.

Sand impactions in a Saskatchewan beef cow-calf herd.

Forty beef cows were reported to show signs of abdominal pain and discomfort over a period of 1 wk. Two of the affected animals died and on postmortem examination were found to be impacted with sand in their abomasum and small intestines. Sand-laden barley silage was found to be the cause of these impactions.

Outcome and long-term follow-up of 20 horses undergoing surgery for caecal impaction: a retrospective study (2000-2008).

REASONS FOR PERFORMING STUDY: If untreated, caecal impaction may progress to rupture of the caecum and reports of long-term outcome for horses undergoing surgery for caecal impaction are required. OBJECTIVES: To describe short- and long-term complication rates for horses undergoing surgery for caecal impaction in an otherwise life-threatening gastrointestinal condition. METHODS: Case records were reviewed for horses undergoing surgery for caecal impaction. Horses were included in the study if an abnormally large, fluid-distended or feed-impacted caecum was the primary diagnosis at surgery and excluded if the caecum had already ruptured upon opening the abdomen, necessitating euthanasia. Short-term follow-up data were obtained from clinical records; and included complications, repeat celiotomy and survival to discharge. Long-term survival was defined as survival for >1 year post operatively. Long-term follow-up data were obtained through telephone interviews with owners and referring veterinary surgeons. Survival, occurrence of post operative colic and subsequent use of the horse were recorded. RESULTS: Twenty horses underwent surgery for caecal impaction: 16 horses underwent caecal bypass (typhlotomy and removal of caecal contents, ileal transection followed by ileocolostomy); 3 underwent typhlotomy alone; and one horse underwent typhlotomy followed by a second procedure where caecal bypass was performed. Five horses (25%) were admitted for colic evaluation with primary caecal impactions, in 10/20 (50%) of cases the impaction was secondary to previous orthopaedic surgery and in 5/20 (25%) caecal impaction was identified at repeat celiotomy following a previous colic surgery. Sixty-five percent (13/20) of horses survived to discharge; 11/13 (85%) of horses discharged survived long term; 100% (3/3) horses that received typhlotomy alone were discharged and survived long term. CONCLUSIONS: The prognosis following caecal impaction surgery is fair, if the horse survives to discharge then prognosis for long-term survival is good. POTENTIAL RELEVANCE: Surgery for caecal impaction carries a fair prognosis for a potentially life threatening disease, in particular where caecal dysfunction is suspected.

Acupuncture for Anaemia and Large Intestine Impaction Associated with Hind Limb Weakness in a Horse: A Case Report.

A 24-year-old horse was presented with a clinical history of anaemia, large intestine impaction and hind limb weakness. Loss of body weight was also reported. Hematocrit and hemoglobin levels were low and piroplasmosis test was negative. Nasogastric intubation with laxative agents was performed and 50 ml of a red blood-cell-supplement was given daily during a month. An assessment following Traditional Chinese Veterinary Medicine (TCVM) principles was performed after the last episode of large intestine impaction. A swollen, pale and wet tongue was observed. A superficial, weak pulse combined punctually with a slippery pulse was detected on the right side. The pulse on the left side was very thin. BL18, BL20 and BL23 were the most sensitive acupoints on the right side. BL18 and BL23 were the most sensitive on the left. TCVM diagnosis was Qi/Yang Kidney Deficiency, Spleen Qi Deficiency with Stagnation and Blood Deficiency. It received acupuncture at Bai-Hui, KI3, KI7, KI10, BL23, GB39, ST36, BL17 and acupressure at SP10. The client reported a significant improvement after treatment and hematocrit and hemoglobin levels were normal. KI3, ST36, BL39 acupoints were treated 14 days later. The outcome was favourable and one acupuncture session per month was recommended. No previous case reports in equines have been documented with a combination of blood, gastrointestinal and musculoskeletal problems in the same episode. This case is an example of an integrative approach to investigate the origin and the interdependent relation between body systems.

Cecal rupture in foals--7 cases (1996-2006).

The objective of this study was to identify risk factors and describe clinical signs in 7 foals with cecal rupture; none of the foals survived. Six foals had undergone general anesthesia; 5 for orthopedic procedures. Six of the foals were receiving nonsteriod anti-inflammatory drugs. Most foals started showing colic signs on day 2 after surgery, preceded in 3 cases by dullness. Cecal rupture occurred between 4 hours and 2 days after the first signs of colic were noticed. Intestinal motility was decreased or absent in all foals for which it was recorded.Foals undergoing general anesthesia should be closely monitored for any sign of dullness, prolonged recumbency, reduced fecal output, and signs of abdominal discomfort for 3 days postoperatively, especially in cases following orthopedic surgery. If any of the above occurs, cecal impaction should be considered as a differential diagnosis. A prompt exploratory laparotomy may be a reasonable diagnostic option before the cecum ruptures with fatal consequences.

Colonic obstruction in three captive reticulated giraffe (Giraffa camelopardalis reticulata).

Fatal colonic obstructions were diagnosed in three captive, adult, reticulated giraffe (Giraffa camelopardalis reticulata). Clinical presentations varied, but all cases displayed decreased activity, anorexia, and considerably decreased fecal production, consistent with intestinal obstruction. Case 1 was diagnosed at necropsy with a phytobezoar obstructing the spiral colon. Case 2 was diagnosed at necropsy with a fecal impaction of the colon. Case 3 was diagnosed during surgery with colonic ileus. Cases 2 and 3 underwent surgical intervention but were markedly compromised by the time of surgery and died during surgery or 24 hr postoperatively. Gastrointestinal obstruction, requiring aggressive supportive care and early surgical intervention, should be considered in giraffe in which anorexia and substantially decreased fecal production are observed. Abdominal exploratory surgery will likely be necessary for diagnosis and treatment. Based on a small number of cases, gastrointestinal obstruction has a poor prognosis in giraffe.

Gastrointestinal impactions in backyard poultry.

In contrast to conventional commercial poultry, which are raised primarily in controlled indoor environments, backyard poultry are typically raised in less restricted settings, potentially exposing them to a greater variety of ingestible substances, including multiple types of forage. Consequently, problems such as gastrointestinal impactions caused by ingesta have been noted in backyard poultry. To determine the prevalence of these impactions in backyard poultry, we performed a retrospective database search for autopsy submissions to the California Animal Health and Food Safety laboratory system and found that gastrointestinal impaction was associated with the death of 42 backyard poultry cases (40 chickens, 1 turkey, and 1 goose) from January 2013 to July 2018. In 32 of these 42 (76%) cases, the impaction was caused by fibrous plant material, 7 (17%) by compacted feed, and 3 (7%) by miscellaneous ingesta (tortilla, plastic, and wood shavings). The large proportion of grass impactions indicate that foraging is the predominant source of impaction material in backyard poultry, and that long grasses may be a significant health hazard for poultry. Backyard, pasture-raised, and free-range poultry producers are advised to maintain short pastures, avoid feeds that may expand in the gastrointestinal tract, and provide adequate grit to prevent impactions.

Physical characteristics of free-living sea turtles that had and had not ingested debris in Microregion of the Lakes, Brazil.

The ingestion of detritus by sea turtles results in high mortality and morbidity. The objective of this study was to describe the characteristics of free-living sea turtles that ingested anthropogenic inorganic detritus in comparison to those that did not. A total of 186 necropsy files were analyzed in marine turtles from the beaches of the Microregion dos Lagos, Rio de Janeiro. Among the turtles that ingested detritus, the mean turtle was female and cachectic, with a carapace length of 36,6 cm, detritus accumulated in the large intestine, and fecal compaction. It seems most likely that's low food transit, combined with the multiplicity of ingestion, favored the accumulation of detritus. This ingestion resulted in cachexia associated with fecal compaction, since the greatest accumulation was in the large intestine. The intake of detritus by turtles was not punctual but continuous. These studies demonstrated the vulnerability of these animals to environmental pollution.

Epidemiology of impaction colic in donkeys in the UK.

BACKGROUND: Colic (abdominal pain) is a clinical condition of serious concern affecting the welfare and survival of donkeys at the Donkey Sanctuary in the UK. One of the most commonly reported causes is due to impacted ingesta in the large intestine ("impaction colic"). However little is known about the incidence of, or risk factors for, this condition. Here we describe the epidemiology of colic in donkeys, specifically impaction colic. We focus on temporal aspects of the disease and we identify environmental and management related risk factors for impaction colic in UK donkeys. RESULTS: There were 807 colic episodes in the population of 4596 donkeys between January 1st 2000 and March 31st 2005. The majority (54.8%) of episodes were due to a suspected or confirmed diagnosis of impaction of the gastrointestinal tract. The mortality risk for all colics (51.1%) was higher than reported in other equids. The incidence rate of all colics (5.9 episodes per 100 donkeys per year) and of impaction colic (3.2 episodes) was similar to that in horses. A retrospective matched case-control study of all impaction colics from January 2003 (193) indicated that older donkeys, those fed extra rations and those that previously suffered colic were at increased risk of impaction. Lighter body weight, musculo-skeletal problems, farm and dental disease were also significantly associated with a diagnosis of impaction colic. CONCLUSION: To our knowledge this is the first study to estimate the incidence rate of colic in a large population of donkeys in the UK. In contrast to other equids, impaction was the most commonly reported cause of colic. We identified several risk factors for impaction colic. Increasing age, extra rations and previous colic are known risk factors for colic in other equids. Results support the hypothesis that dental disease is associated with impaction colic. Musculo-skeletal problems may be associated with colic for various reasons including change in amount of exercise or time at pasture. Other associated factors (weight and farm) are the subject of further research. Identification of risk factors for impaction colic may highlight high risk donkeys and may allow intervention strategies to be introduced to reduce the incidence of the disease.

Outcome of medical and surgical treatment of cecal impaction in horses: 114 cases (1994-2004).

OBJECTIVE: To determine short- and long-term outcomes, including recurrence rates, for horses with cecal impaction treated medically or surgically. DESIGN: Retrospective case series. ANIMALS: 114 horses. PROCEDURES: Medical records were reviewed for information on signalment, history, clinical findings, treatment (medical vs surgical), and short-term outcome. Information on longterm outcome was obtained through a mail survey and telephone interview with owners. RESULTS: 54 horses were treated medically, 49 horses were treated surgically, and 11 horses were euthanized after initial examination without further treatment. Horses treated surgically were significantly more likely to have signs of moderate or severe pain than were horses treated medically. Forty-four of the 54 (81%) horses treated medically were discharged from the hospital. Twelve of the 49 horses treated surgically were euthanized at surgery because of cecal rupture. Thirty-five of the 37 (95%) horses that were allowed to recover from surgery were discharged from the hospital. In 34 horses treated surgically, typhlotomy without a bypass procedure was performed. Long-term (>or= 1 year) follow-up information was available for 19 horses treated medically and 28 horses treated surgically. Eighteen (95%) and 25 (89%) of the horses, respectively, were alive at least 1 year after treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that medical and surgical treatment were both associated with favorable outcomes in horses with cecal impactions. In this population, typhlotomy alone without cecal bypass was associated with a low recurrence rate. The long-term prognosis for horses that were discharged from the hospital was good.

Intra-abdominal fungal pseudomycetoma in two cats.

BACKGROUND: Pseudomycetomas are deep cutaneous to subcutaneous lesions caused by Microsporum canis mainly described in Persian cats, with few reports of intra-abdominal location. This report describes the clinical signs and lesions of intra-abdominal pseudomycetomas caused by M. canis in two Persian cats. CASE REPORT: Two Persian cats with a history of previous laparotomy (ovariohysterectomy and nephrostomy) and fecal impaction were examined. Cat #1 was euthanized and subjected to necropsy, histopathology and mycological evaluation. Cat #2 presented with chronic dermatophytosis, and an intra-abdominal mass, that was subjected to histopathology evaluation. Cat #1 presented at necropsy a white-grayish, firm mass (6cm×3.5cm×2.8cm) in the uterine cervix. Cat #2 presented a firm whitish mass (6.5cm×1.5cm×0.5cm) located close to the left kidney. Histologically, both masses contained multifocal granules with hyphae and spores surrounded by Splendore-Hoeppli reaction, with a pyogranulomatous inflammatory infiltrate and fibrous connective tissue proliferation in the periphery. Hyphae and spores exhibited marked Grocott and periodic acid-Schiff staining. M. canis was identified by fungal isolation in cat #1. CONCLUSIONS: Pseudomycetoma should be considered as a differential diagnosis in cats, especially in Persian cats presenting with an intra-abdominal mass. Entrance of the agent into the cavity can occur during laparotomy.

Ileal impaction in 22 cows.

The clinical signs, diagnosis, treatment and outcome of 22 cows with ileal impaction were investigated using the medical records of bovine patients referred to the Department of Farm Animals, Vetsuisse Faculty, University of Zurich from 1993 to 2003. Only 15 of the cows had signs of colic, which were subtle but slowly increased in severity in some patients. The results of haematological and biochemical analyses were mildly abnormal in only few animals. There was no correlation between the duration of the disorder before admission, the severity of symptoms and the results of the haematological and biochemical analyses. Dilated loops of small intestine in the right dorsal quadrant of the abdomen could be palpated transrectally and imaged via ultrasonography. A definitive diagnosis of ileal impaction was made during exploratory laparotomy by finding the impaction and ruling out other abnormalities. In 19 cows, the obstructing food mass was easily massaged into the caecum, and in three animals an enterotomy was carried out. All cows had an uneventful recovery with no recurrence of the disorder. It is concluded that the cause of the impaction was most likely due to seasonal influences and winter-feeding with a hay based ration. The short and long-term prognosis after surgical intervention was good.

Post anaesthetic colic in horses: a preventable complication?

REASONS FOR PERFORMING STUDY: There is little information on the prevalence of, and risk factors associated with, post anaesthetic colic (PAC) in horses undergoing nonabdominal operations. OBJECTIVES: To undertake the first prospective study of prevalence of PAC and identify risk factors in its development in nonabdominal procedures. METHODS: A multicentre prospective case-control study was conducted, on every horse undergoing anaesthesia for a nonabdominal procedure between April 2004 and June 2005. Colic cases were defined as any horse with recognised signs of abdominal pain within 72 h of general anaesthesia that could not be attributed to any concurrent disease. Five control horses per case were selected randomly from the study population at all hospitals. Multivariable logistic regression analysis was used to examine the relationship between predictor variables and the risk of developing PAC. RESULTS: The estimated mean prevalence of PAC in the study population was 5.2% (95% CI, 2.8, 8.0). However, the prevalence of colic varied between each centre. The most commonly diagnosed cause of colic was impaction. Multivariable analyses showed that the centre involved and the type of surgery performed were associated with an increased risk of PAC. Preoperative food deprivation and the use of opioid drugs were confounding factors. CONCLUSIONS: Prevalence of PAC varied significantly between the 4 hospitals studied; there may be hospital-related covariates that account for this. The type of surgery performed influenced the risk of PAC. POTENTIAL RELEVANCE: Identifying the risk factors for PAC is a prerequisite for its prevention. This study indicates horses at increased risk of PAC that might benefit from a more critical evaluation of post anaesthetic gastrointestinal function and/or the provision of preventative measures. Further investigation is required to explain the variation in prevalence of PAC between centres.

Predisposing factors for small colon impaction in horses and outcome of medical and surgical treatment: 44 cases (1999-2004).

OBJECTIVE: To identify factors associated with development of small colon impaction in horses and with selection of medical versus surgical treatment and to determine the prognosis for affected horses following medical or surgical management. DESIGN: Retrospective case series. ANIMALS: 44 horses with primary impaction of the small colon. PROCEDURES: Medical records were reviewed for signalment, history, clinical findings, treatment (medical vs surgical), hospitalization time, and outcome. For comparison purposes, the same information was collected for 83 horses with primary impaction of the large colon. RESULTS: Diarrhea was the only factor found to be associated with development of small colon impaction. Horses with small colon impaction were 10.8 times as likely to have diarrhea at the time of initial examination as were horses with large colon impaction. Abdominal distension was the only factor associated with use of surgical versus medical treatment. Horses with small colon impaction that were treated surgically were 5.2 times as likely to have had abdominal distension at the time of admission as were horses with small colon impaction that were treated medically. Overall, 21 of 23 (91%) horses treated medically and 20 of 21 (95%) horses treated surgically survived to discharge. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that diarrhea may be a risk factor for development of small colon impaction and that horses with small colon impaction that have abdominal distension at the time of initial examination are more likely to require surgical than medical treatment.