Intestinal neoplasia: A review of 34 cases

The clinicopathological features of 34 horses with a histological diagnosis of intestinal neoplasia were reviewed; these included 17 horses with lymphoma, five with gastrointestinal stromal tumours (GISTs), four with adenocarcinomas, three with leiomyosarcomas, two with leiomyomas, two with squamous cell carcinomas (SCC) and one with adenocarcinoma/mesothelioma. The mean age at presentation was 19 years (range 3–36 years), and 81% of cases occurred in horses aged 15 years or older. Weight loss, acute or recurrent colic, inappetence, diarrhoea, depression and pyrexia were the most common presenting clinical signs. Hyperfibrinogenaemia, hypoalbuminaemia and leukocytosis were the most common clinical pathological findings. Transabdominal ultrasonography and exploratory laparotomy were the most useful diagnostic tests. Neoplasia was identified in all regions of the intestinal tract, with the jejunum being most frequently affected. The presence of mass lesions or thickened intestinal walls on transabdominal ultrasound, coupled with other clinical findings, were suggestive of intestinal neoplasia. Where possible, complete surgical resection offered the best prognosis, but generally the prognosis was poor to hopeless.     

Putative intestinal hyperammonaemia in horses: 36 cases

Reasons for performing the study: Intestinal hyperammonaemia (HA) has been infrequently reported in individual horses; however, there have been no studies describing clinical and laboratory data as well as short‐ and long‐term outcome in a larger number of cases. Objectives: To describe clinical and laboratory data and short‐ and long‐term outcome in a large group of horses with intestinal HA. Methods: Multi‐centred, retrospective study; case records of horses with HA were reviewed and any horse with a clinical or post mortem diagnosis of intestinal HA was included. Hyperammonaemia was defined as a blood ammonium (NH₄⁺) concentration ≥60 µmol/l and horses with a diagnosis of primary hepatic disease were excluded. Relevant data were recorded and, if appropriate, data from survivors were compared to nonsurvivors to identify potential prognostic indicators. Results: Thirty‐six cases, 26 mature horses and 10 foals with intestinal HA were identified. Case histories included diarrhoea, colic and neurological signs and the most common clinical diagnosis was colitis and/or enteritis. The most common clinical and laboratory abnormalities included tachycardia, increased packed cell volume, hyperlactataemia and hyperglycaemia. Fourteen horses (39%) survived to discharge; NH₄⁺ concentration on admission was the only parameter significantly associated with survival. All surviving horses and foals for which follow‐up information was available recovered completely and returned to their intended use without further complications. Conclusions and potential relevance: Intestinal HA occurs in mature horses and foals and can be associated with severe clinical and laboratory abnormalities; further studies are required to investigate predisposing factors and delineate possible differences in aetiologies.     

Small intestinal segmental volvulus in horses after gastroscopy: Four cases (2011–2012)

Gastroscopy is the most common technique used in veterinary medicine to evaluate the stomach in horses and to date, no complications have been described associated with the procedure. This paper reports 4 cases developing a nonstrangulating segmental volvulus of the small intestine after gastroscopy at 3 referral institutions over a 2 year period. After performing diagnostic gastroscopy, all horses developed acute and severe clinical signs of colic unresponsive to medical management. Time range between gastroscopy and onset of colic signs varied from 10 min to 3 h. An exploratory laparotomy revealed a nonstrangulating segmental volvulus of the small intestine that was manually corrected without need for resection in all horses. In all cases, affected small intestine was severely gas distended. Three of those horses survived to discharge and were alive at follow‐up. One horse was subjected to euthanasia 2 days after surgery due to diffuse intestinal lymphoma.     

Atypical presentation of caecal perforation in two horses

This case report describes retroperitoneal and subserosal emphysema as the primary indication of a caecal perforation associated with an episode of colic. Feed contamination was not noted on repeated peritoneal fluid samples or within the peritoneal cavity at the time of surgery; however, subserosal and retroperitoneal emphysema at the base of the caecum was identified during surgical exploration, which later corresponded to retroperitoneal caecal perforation at necropsy examination.     

Small intestinal volvulus in 115 horses: 1988-2000

OBJECTIVE: To evaluate the historical data, signalment, clinical signs, results of laboratory analyses, treatment, and outcome of horses with small intestinal (SI) volvulus. STUDY DESIGN: Retrospective study. SAMPLE POPULATION: One hundred and fifteen client-owned horses, aged 1 month to 21 years. METHODS: Clinical signs, laboratory data, surgical or necropsy findings, and outcome for horses with SI volvulus were obtained from medical records, identified by computer search and manual review. RESULTS: There was no statistical difference in signalment between cases and the hospital population. Seventy-four percent of horses were >/=3 years. There were considerable variations in clinical signs on admission; high heart rate and signs of severe pain were not consistent features. Examination per rectum identified distended small intestine in only 69% of horses. One hundred horses had surgery, and small intestine resection was performed in 25. Eighty-four horses were recovered from surgery, and 67 horses survived to hospital discharge (80% of horses recovered from surgery, 58% of 115 horses). Forty-eight percent that were ultimately discharged had a post-operative complication and these horses had a longer average stay than horses with no complication (11 days versus 8.9 days). CONCLUSIONS: We identified 115 horses with primary SI volvulus over a 12-year period. We found that the population of horses with this lesion was older than has previously been reported and that the prognosis for post-operative survival to hospital discharge is good (80%). Post-operative complications were common, and affected approximately half the horses that were ultimately discharged from the hospital. CLINICAL RELEVANCE: This information may aid diagnosis and prognosis and guide decision making for horses with this condition.     

Hypothesis on the pathophysiology of small intestinal strangulation by a pedunculated lipoma

The current hypothesis proposed for strangulation of small intestine by a pedunculated lipoma in horses involves movement of the lipoma around the small intestine until it loops through its own pedicle. This mechanism is difficult to demonstrate during surgical correction. The objective was to examine an alternative explanation for strangulation by pedunculated lipomas that is logical and consistent with intraoperative findings by the analysis of the anatomical features of 11 cases of lipoma strangulation in horses. In the proposed hypothesis, the stalk of the lipoma is tensed by the weight of the lipoma alone or by external forces on it from adjacent intestine. This produces a slit-like aperture formed by the stalk and the contiguous mesentery. One or more loops of intestine pass across the lateral edge of the stalk before turning into this aperture, either because of lack of space in the abdominal cavity or through the effects of peristalsis. The weight of the intestine itself causes the loop to ‘fall’ into the aperture and become entrapped. This creates a half-hitch knot in which the loop of intestine uses the lipoma pedicle as a ‘post’ around which it becomes strangulated. It was concluded that the proposed hypothesis differs from the existing one by requiring intestinal movement to create the strangulation, which is more plausible than the current proposal that the strangulation is caused by movement of the lipoma itself. It is also more consistent with surgical findings.     

Large colon resection and anastomosis in horses: 52 cases (1996-2006)

Reasons for performing study: Large colon resection and anastomosis (LCRA) is the most aggressive method of surgical management of a colon with questionable viability. Currently, published studies are comprised mostly of broodmares and discuss short‐term survival. Objectives: To determine the prognosis for survival after LCRA in a diverse population of horses, report the incidence of post operative complications, and determine if associations between analysed variables and survival rate exist. Methods: The medical records of 52 horses that underwent LCRA were evaluated. Data were used to identify univariable associations with survival as well as complications related to LCRA. Chi‐square, odds ratio with 95% confidence interval, Mann‐Whitney or Kruskal‐Wallis tests were used, with significance set at P<0.05. Results: Forty‐four horses (84.6%) survived anaesthesia and recovery, 30 (57.7%) survived to be discharged from the hospital. Of the variables analysed, heart rate 24 h after recovery was significantly associated with mortality, as were endotoxaemia, ileus and peritonitis experienced post operatively. Conclusions: Heart rate 24 h after recovery may be a more reliable prognostic indicator than other analysed variables. Survival rate and complications after LCRA were similar to those previously reported. Potential relevance: By reporting on LCRA in a diverse group of horses, referral clinics with similar populations may have a better understanding of prognosis and complications associated with the procedure. When a colon with questionable viability is removed, waiting until 24 h after recovery may be advised to allow for a more informed decision regarding prognosis.     

Plasma trypsin level in horses suffering from acute intestinal obstruction

Gastrointestinal disorders in horses leading to endotoxic shock could have further consequences on other splanchnic organs such as the pancreas, as can be seen in humans suffering from septic shock. In this study, the range of enzymatically active trypsin (EAT) in healthy horses was established and is similar to the range observed in healthy humans. EAT values were determined in horses with acute abdominal crises on admission as well as during anaesthesia and in the postoperative phase. A significant increase in plasma EAT was found in 59% of the horses with surgical colic when compared to our established reference range. Significantly higher values were found in severe shock cases. When separated in groups according to the duration of colic before referral, significantly higher EAT values were observed in the non-survivor group compared to the survivor group of colics of short duration. EAT plasma values increased significantly during the postoperative phase, and were significantly higher in small intestine obstructions than in large bowel disorders. In human medicine, hypovolaemic or septic shock patients show an increase in pancreatic proteases. Splanchnic hypoperfusion during shock could lead to pancreatic damage resulting in trypsin liberation into the peritoneal space and an increase in plasma levels. Trypsin is able to activate inflammatory cascades and leucocytes and could play a role in multiple organ failure. Further studies are needed to evaluate the implications of changes in plasma trypsin in the disease process of equine acute abdomen and to demonstrate possible pancreatic damage.     

Return to use and performance following exploratory celiotomy for colic in horses: 195 cases (2003–2010)

Reasons for performing study: There are few objective data on return to use and performance in horses following colic surgery. Objective: To investigate return to functional use of horses following colic surgery and factors associated with a negative outcome. Methods: The North Carolina State University Equine Colic Database was reviewed for horses that underwent exploratory celiotomy for colic (2003–2010). Horses were excluded from the study if they survived <6 months, had no intended use preoperatively, or if further data were not available at attempted follow‐up. Information retrieved included history, background, use, and selected pre‐, intra‐, and post operative factors. Telephone interviews were used to obtain follow‐up data. Logistic regression was used to investigate associations between clinical data and outcome, reported as odds ratios with a 95% confidence interval and corresponding P value. Results: Of patients surviving to 6 months, 133/195 (68%) were performing their intended use and 85/156 (54%) were at or above preoperative performance. At one year, 145/190 (76%) horses were performing their intended use and 101/153 (66%) were at or above preoperative performance. Animals were significantly less likely to return to use/performance if they had a previous celiotomy, stall rest for an orthopaedic condition, a nonstrangulating lesion type, incisional hernia, diarrhoea or laminitis. Conclusions: The overall prognosis for return to use and performance following colic surgery is fair to good. Multiple pre‐ and post operative factors may affect the likelihood of return to use and performance. Potential relevance: Targeted owner education regarding preoperative lameness, post operative rehabilitation and treatment for complications, such as incisional hernioplasty, may help inform owners about their horse's potential for return to use and performance following colic surgery.     

Review of gastric rupture in the horse

Gastrointestinal rupture is an important cause and complication of equine colic. The stomach is the most commonly affected segment in the gastrointestinal tract involved in gastrointestinal rupture. Gastric rupture can be primary or secondary; however, unless prodromal clinical signs are identified, localised and corrected, the resulting peritoneal contamination with feed, intestinal secretions and bacteria is invariably fatal. Causes for gastric rupture may be known or idiopathic; however, factors that predispose a horse to gastric rupture are poorly understood. Further research is needed to identify underlying causes and pathophysiology of gastric rupture to prevent it from occurring.     

Small intestinal volvulus in a free-ranging female dugong (Dugong dugon)

An adult female dugong (Dugong dugon) was found dead and floating in Moreton Bay, Queensland, Australia. This animal was found to have a 360° mesenteric volvulus with infarction of the associated segment of small intestine, and fibrinous peritonitis. Mortality was attributed to the volvulus and its sequelae. The cause was not apparent on gross or histological examination.