Comparison of surgical versus medical treatment of nephrosplenic entrapment of the large colon in horses: 19 cases (1992-2002)

Effects of xylazine and adrenaline combinations: Preliminary clinical application for non-surgical protocols of nephrosplenic entrapment in horses

Background and Aim:

The medical treatment of horses with nephrosplenic entrapment (NSE) of the large colon through administrating phenylephrine and rolling during general anesthesia was effective and less expensive than surgical treatment. However, the selection of drugs for non-surgical treatment of NSE is not a usual method for clinical practice. This study aimed to identify the effects of combined drugs on the cardiac and splenic response in horses and provide information on the NSE of the large colon for clinical application.

Materials and Methods:

Six healthy Thai native crossbred horses were enrolled in this study. Horses received two protocols with a withdrawal period of 14 days: Group 1 received xylazine (0.5 mg/kg IV) and adrenaline (1 mcg/kg IV), and Group 2 received xylazine (0.5 mg/kg IV) and adrenaline (3 mcg/kg IV). Heart rate (HR), HR variability (HRV), heart dimensions, and the splenic response of six horses were measured before the sedation, 30 and 60 min later, and 65, 70, 75, 80, 90, and 100 min after adrenaline administration. Doppler was used to obtain systolic blood pressure.

Results:

The HRV low-frequency and high-frequency power ratios decreased after using xylazine. Hypertension was observed after adrenaline administration. In this study, there were only minimal differences in the HR and respiratory rate between groups. However, overall cardiac and splenic parameters were statistically higher in Group 2.

Conclusion:

This study suggested that xylazine and three micrograms of adrenaline preserved the cardiac autonomic activity balance and were safe to use non-surgical applicability in horses.

Evaluation of phenylephrine and exercise with or without trocarization for treatment of suspected nephrosplenic entrapment in horses

OBJECTIVE To report the outcomes of horses with suspected nephrosplenic entrapment (NSE) of the large colon treated by IV phenylephrine administration and exercise with and without trocarization (ie, medical management). DESIGN Retrospective, observational study. ANIMALS 134 horses. PROCEDURES Electronic medical records were searched to identify horses that underwent medical management for suspected NSE at a veterinary teaching hospital between 1995 and 2014. Demographic information, physical and ultrasonographic examination findings, treatment information (including the number of times the treatment was performed and patient response), surgical findings if applicable, complications, and patient outcome were recorded. Descriptive statistics were reported. RESULTS 72 horses had suspected NSE that resolved with medical treatment; 59 of 62 horses underwent laparotomy when medical management failed, and 3 were euthanized without surgery. Twenty-five of the 59 horses had confirmed NSE that was surgically corrected, and 34 had lesions other than or in addition to NSE. All horses that had surgically corrected NSE and 18 of 34 horses that had other lesions survived to hospital discharge. The odds of resolution of NSE with medical management were greater for horses that underwent ≤ 2 (vs > 2) treatments. The treatment success rate for horses that underwent trocarization was not greater than that for horses that did not have the procedure. CONCLUSIONS AND CLINICAL RELEVANCE Suspected NSE resolved with the described medical management for most horses. However, results indicated the potential for misdiagnosis was high. Timely surgical intervention is recommended for horses that fail to respond to medical treatment.

Meta-analysis of the Effect of Treatment Strategies for Nephrosplenic Entrapment of the Large Colon

A variety of treatment strategies for nephrosplenic entrapment of the large colon are reported, with conflicting evidence in the published literature as to the preferred treatment option. The aim of this study is to provide a systematic meta-analytical assessment of the efficacy of different treatment strategies in horses with confirmed or suspected nephrosplenic entrapment. This study involves meta-analysis including nonrandomized studies. A comprehensive literature search was performed from January 1970 to January 2017. Inclusion criteria were retrospective studies involving horses with confirmed and suspected nephrosplenic entrapment. A meta-analysis was performed using a random effects model, with the effect size calculated as an odds ratio (OR) with 95% confidence intervals. Statistical significance was P < .05. Out of 84 peer reviewed publications that met the search criteria, 19 relevant studies were identified. Using an OR as the effect size, the meta-analysis noted that the choice of medical or surgical therapy had no statistically significant effect on survival (P = .134). Patients treated via the rolling technique were no more likely to resolve with medical management than those treated via jogging (P = .187). Patients treated with phenylephrine were no more likely to exhibit medical resolution than patients that did not receive phenylephrine, either when all medical treatment methods were considered (P = .290), or when rolling under general anesthesia was used (P = .331). Treatment strategy, including medical versus surgical therapy, does not affect the likelihood of resolution of nephrosplenic entrapment. However, the lack of randomized trials means the results should be treated with caution and case selection remains important..

Ultrasound of the equine acute abdomen

Abdominal ultrasound is an invaluable aid in the evaluation of the colic patient but can be heavily influenced by patient preparation, individual horse-to-horse variation, availability of ultrasound transducers, technique, experience level of the examiner, and complexity of the abdominal disorder. This article describes ultrasonographic anatomy of the normal equine abdomen and technique for examination of the equine colic patient. Common abnormalities of the stomach, small intestine, large intestine, and peritoneal cavity are described along with other abnormalities that may be discovered with abdominal ultrasonography of the colic patient, such as masses, urolithiasis, cholelithiasis, and thoracic or cardiac lesions.

Comparison of phenylephrine administration and exercise versus phenylephrine administration and a rolling procedure for the correction of nephrosplenic entrapment of the large colon in horses: 88 cases (2004-2010)

OBJECTIVE

To compare the outcome of horses with nephrosplenic entrapment of the large colon (NSELC) that were treated nonsurgically by IV administration of phenylephrine and exercise with that of horses treated by IV administration of phenylephrine and a rolling procedure under general anesthesia.

DESIGN

Retrospective case series.

ANIMALS

88 horses with NSELC.

PROCEDURES

Horses examined between 2004 and 2010 because of acute abdominal pain that had NSELC on the basis of findings on abdominal palpation per rectum, abdominal ultrasonography, or both were included. Medical records were reviewed to obtain information on treatment (IV administration of phenylephrine and exercise vs IV administration of phenylephrine and a rolling procedure) and outcome.

RESULTS

Overall, 85% (75/88) of horses with NSELC responded to exercise or rolling under general anesthesia. The success rate of rolling under general anesthesia (42/50 [84%]) was significantly higher than the success rate of exercise after IV administration of phenylephrine (24/38 [63.2%]). Resolution of NSELC was achieved by rolling under general anesthesia in 8 of 14 horses that initially failed to resolve with exercise.

CONCLUSIONS AND CLINICAL RELEVANCE

A rolling procedure performed under general anesthesia had a higher success rate than exercise after IV phenylephrine administration for resolution of NSELC in horses, suggesting that rolling could be considered as the initial medical treatment. The rolling procedure may be labor intensive and should only be attempted in a surgical facility in the event that exploratory laparotomy is required.

Rolling technique for treatment of left displacement of the large colon in horses: 11 cases (2004-2009)

The left displacement of the large colon, a condition that commonly occurs in horses, has two clinical manifestations. Different treatments including medical treatment, rolling the horse under general anesthesia or surgical correction have been recommended. The diagnosis can often be made by rectal examination and confirmed by percutaneous ultrasonography. During the period between 2004 and 2009, 11 horses were treated for left displacement of the large colon by rolling the horses under general anesthesia, using a slightly different technique than the ones previously described. The clinical case selection was based on rectal palpation confirmed with ultrasonogram. Nine animals were successfully treated and two had to be submitted to surgery after three attempts of rolling. No short or long term complications were observed after the procedure. Only one animal had a recurrence of the clinical manifestation 10 months after the first treatment and was successfully rolled once again. Despite a bit different from the other rolling procedures, this also proved to be an effective procedure. Rolling a horse even when attempted more than once showed to be a safe procedure, however, we reinforce the need for special attention following the procedure in order to establish proper emergency procedures in case complications occur.

Reevaluation of the effect of phenylephrine on resolution of nephrosplenic entrapment by the rolling procedure in 87 horses

OBJECTIVE

To evaluate the outcome in horses treated with a rolling technique or surgically for nephrosplenic entrapment of the large colon (NSE) and to examine the benefit of phenylephrine (PE) HCl on the efficacy of nonsurgical (rolling) management of NSE.

STUDY DESIGN

Case series.

ANIMALS

Horses (n = 211) diagnosed with NSE by rectal palpation with or without ultrasonography, or at the time of exploratory celiotomy or necropsy.

METHODS

Medical records (January 1, 2001-September 1, 2008) were collected from horses diagnosed with NSE at 2 referral centers. Records were used to obtain signalment, physical exam findings, laboratory results, ultrasonographic findings, the use of PE HCl, the specific treatment used, and outcome. Rectal findings indicative of NSE were: (1) palpation of large colon within the nephrosplenic space or (2) palpation of colonic bands coursing dorsally toward the nephrosplenic space in association with ultrasonographic findings suggestive of NSE.

RESULTS

Rolling was successful in 50 of 87 (58%) horses, 85 horses (98%) survived to discharge. Horses (n = 155) that were treated surgically (42 of which had previously undergone the rolling procedure) had a 94% short-term survival rate. Premedication with PE resulted in no significant difference (P = .91) in resolution of NSE by rolling.

CONCLUSIONS

Resolution of NSE by rolling was not significantly affected by premedication with PE in the population studied.

Severe phenylephrine-associated hemorrhage in five aged horses

CASE DESCRIPTION

5 aged (≥ 17 years old) horses developed life-threatening Internal hemorrhage following IV administration of phenylephrine at 3 hospitals.

CLINICAL FINDINGS

All 5 horses developed severe hemothorax, hemoabdomen, or both within minutes to hours following administration of phenylephrine.

TREATMENT AND OUTCOME

Four of 5 horses died of hemorrhagic shock, and 1 horse survived with a blood transfusion. The exact source of hemorrhage was Identified In only 1 horse. Medical records of all horses with nephrosplenic entrapment of the large colon and treated with phenylephrine at the University of Florida Veterinary Medical Center between 2000 and 2008 (n = 74) were reviewed. Three of these 74 (4%) horses developed fatal hemorrhage (horses 1 through 3 of this report). The risk of developing phenylephrine-associated hemorrhage was 64 times as high (95% confidence interval, 3.7 to 1,116) in horses ≥ 15 years old than in horses < 15 years old.

CLINICAL RELEVANCE

The potential risks versus benefits of phenylephrine administration should be evaluated carefully, especially In old horses.

Use of ultrasonography to diagnose large colon volvulus in horses

OBJECTIVE

To describe the use of ultrasonography to diagnose large colon volvulus (LCV) in horses.

DESIGN

Descriptive report.

ANIMALS

4 horses with clinical signs of abdominal pain.

PROCEDURE

Each horse was administered analgesic agents for pain control and placed in stocks. Ultrasonographic evaluations were performed with a 3.5-MHz sector scanning transducer that was placed parallel to the long axis of the horse (longitudinal imaging) over an area of the left ventral aspect of the abdomen. The boundaries of the evaluated region included the ventral midline, 2 vertical lines at the level of the left 10th and 17th intercostal spaces, and a horizontal line between the 2 vertical lines at the level of the costal arch of the left 10th intercostal area.

RESULTS

In all horses, nonsacculated large colon was identified ultrasonographically in the left ventral portion of the abdomen; this finding was considered indicative of LCV. In 3 horses, the LCV involved intestinal rotation of 180 degrees, whereas in 1 horse, the LCV involved intestinal rotation of 540 degrees. As confirmed by surgical or postmortem findings, the degree and location of the volvulus were correctly estimated from ultrasonographic images.

CONCLUSIONS AND CLINICAL RELEVANCE

In horses, this method of diagnosis of LCV appears to be of value regardless of the location at which the rotation of the large colon occurs. Ultrasonographic findings may aid in the earlier diagnosis of LCV in horses, especially at an early stage of the disease when other clinical signs are equivocal.