Large Colon Volvulus: What the Research Says
Evidence from 20 peer-reviewed studies
What Professionals Should Know
- •Dexmedetomidine given as a preconditioning agent before large colon volvulus surgery may offer histologic protection against ischaemia-reperfusion damage and reduce mucosal injury
- •While promising in this controlled experimental model, clinical applicability is limited; results suggest investigating postconditioning protocols may be more feasible for field colic cases
- •This research supports further investigation of dexmedetomidine as a therapeutic intervention in suspected large colon volvulus cases, though clinical trials in actual colic cases are needed
- •Post-operative reflux in large colon volvulus cases is an important complication to monitor for, as its presence carries a grave prognosis with only 44% surviving to discharge
- •Horses developing reflux after LCV surgery require aggressive management and owners should be counselled on significantly reduced survival odds compared to non-reflux cases
- •Early detection and treatment protocols for post-operative reflux in LCV cases are critical, as this complication marks a major shift in prognostic outlook
- •Check peripheral lactate before and after manual correction of colon volvulus — values of ≥3.2 mmol/L initially and ≥5 mmol/L post-correction suggest guarded prognosis and warrant honest owner conversations about discharge likelihood
- •If colonic biopsy is obtained, severe mucosal hemorrhage (score ≥3) and abnormal tissue architecture (I:C ratio >1) indicate greater risk of mortality; colonic venous lactate alone is not a reliable prognostic indicator
- •Peripheral and arterial lactate measurements are more clinically useful than colonic venous samples for immediate post-operative prognostication in colic surgery
- •Protein biomarkers identifying intestinal progenitor cells may provide objective prognostic indicators for large colon volvulus cases, helping determine tissue viability at surgery
- •Assessment of progenitor cell populations could aid in clinical decision-making regarding surgical intervention versus medical management in cases with questionable tissue viability
- •Understanding progenitor cell involvement in post-ischaemic epithelial repair may lead to targeted therapies to improve survival outcomes in large colon volvulus
- •Early referral and prompt surgical treatment are critical—each hour of delay before admission reduces survival chances in mares with large colon volvulus
- •Monitor packed cell volume, intra-operative blood pressure stability, and post-operative heart rate and digestive function as indicators of prognosis and complications
- •Communicate to owners that mares with large colon volvulus have good overall prognosis (88% survival) when treated surgically, but outcomes depend heavily on time from onset of colic to surgery
- •When presented with large colon volvulus, obtain and carefully assess pelvic flexure biopsies—quantified mucosal haemorrhage and interstitium-to-crypt ratio provide objective prognostic information that can guide owner counselling and decision-making
- •Consider Thoroughbred breed as a negative prognostic factor; this may warrant more cautious initial prognostication in this population
- •Decide on colonic resection based on clinical indications rather than expected impact on survival, as resection alone does not significantly alter short-term outcome in this cohort
- •Faecal microbiota composition—particularly elevated Proteobacteria and reduced Firmicutes—may provide predictive markers for postpartum colic risk; monitoring these changes could identify high-risk mares for preventive intervention.
- •Foaling itself causes minimal microbiota disruption, suggesting postpartum colic risk is linked to pre-existing microbial dysbiosis rather than the birth event, allowing for pre-emptive management strategies.
- •Specific bacterial families (Lachnospiraceae and Ruminococcaceae) are protective against large colon volvulus; future probiotics or dietary interventions targeting these taxa may help prevent this life-threatening condition.
- •Mucosal membrane pallor, prolonged capillary refill time, and elevated heart rate should be used to counsel owners on realistic prognosis before referral for colic surgery
- •Refer horses with surgical colic to hospitals with board-certified surgeons when possible, as certification status significantly influences survival outcomes
- •Expect approximately 1 in 4 horses with surgical colic will be euthanized intraoperatively; use clinical parameters to discuss this possibility with owners early in case management
- •Preoperative assessment including arterial blood gas analysis helps prognosticate survival likelihood before surgery in large colon volvulus cases
- •Monitor specific intraoperative physiologic parameters as indicators of outcome; adjust management strategy accordingly
- •Decision-making regarding colon resection versus conservative management should incorporate physiologic assessment data
- •Monitor tall mares with previous foaling history and horses with recurrent colic episodes closely, as these populations have higher LCV risk
- •Be alert to horses on recent non-anthelmintic medications or displaying quidding behaviour as potential LCV candidates
- •Review management practices for at-risk horses: minimise unnecessary stabling, standardise forage feeding, avoid rapid pasture or dietary changes, and ensure consistent caregiver routines
- •Do not rely solely on colonic luminal pressure measurements to predict survival in large colon volvulus cases; use as part of a broader clinical assessment
- •CLP measurements may have slightly better predictive value for manual correction cases than for resection and anastomosis cases
- •Consider additional prognostic variables beyond CLP when counseling clients on expected outcomes after large colon volvulus surgery
- •Nearly half of colicky horses have concurrent gastric ulceration—consider gastroscopic examination and ulcer treatment alongside addressing the primary abdominal condition
- •Medical colic cases show higher ulceration rates than surgical cases, suggesting gastric ulceration may be associated with less severe primary lesions or represents a secondary complication of painful states
- •Duodenitis-proximal jejunitis shows a concerning association with gastric ulceration; monitor these cases closely for ulcer development and consider prophylactic or therapeutic ulcer management
- •When horses or ponies present with colic signs unresponsive to medical treatment and large colon displacement or volvulus is suspected, consider that a small colon faecalith may be the underlying cause—this diagnosis is easily missed on ultrasound and rectal exam
- •Small colon obstruction from faecaliths can trigger secondary large colon tympany and displacement; suspect this cascade when pre-operative diagnostics suggest only large colon pathology
- •Be prepared to find incidental small colon faecaliths during exploratory surgery for large colon colic cases, as this combination appears more common than previously reported in literature
- •LDFS can be used intraoperatively to assess large intestinal viability in strangulation cases by measuring oxygen saturation and blood flow — horses with lower postoperative tSo2 and tBF had worse survival outcomes
- •Pelvic flexure microperfusion remains compromised even after correction, warranting careful assessment of this region during surgery
- •Consider LDFS as an adjunct diagnostic tool to guide decisions on resection versus preservation of compromised intestinal segments
- •Neonatal foals with meconium impaction unresponsive to standard medical therapy should be evaluated urgently for atresia coli and consider surgical intervention early.
- •Type 3 atresia coli may complicate colic presentation by predisposing to secondary large colon volvulus.
- •Post-mortem examination and histopathology should be performed on neonatal foal deaths from atresia coli to better understand the condition's pathophysiology and associations.
- •When treating large colon impactions, consider administering smaller volumes of fluids more frequently rather than large single doses (8-10 liters) to reduce acute abdominal distension risk
- •Screen for concurrent gastric impaction before aggressive enteral fluid therapy, as the combination significantly increases volvulus risk
- •Sudden pain escalation unresponsive to analgesics after large-volume fluid administration warrants immediate surgical referral for volvulus evaluation
- •PAR2 activation appears to be a key driver of the inflammatory cascade in colon volvulus; understanding this mechanism may inform future anti-inflammatory treatment strategies beyond current supportive care
- •The upregulation of chemokines (CXCL1, IL-8, MIP-2β) confirms severe intestinal inflammation occurs during volvulus and may help explain poor prognosis outcomes in clinical cases
- •Early intervention and management of ischemic-reperfusion injury should target inflammatory pathways, as PAR2-mediated inflammation appears central to tissue damage
- •Left ventral paramedian colopexy offers good long-term survival and reproductive outcomes for thoroughbred broodmares with large colon disorders—most mares can return to breeding soundly
- •Monitor closely for SIRS, diarrhea, and thrombophlebitis postoperatively as these significantly affect survival; their presence should guide intensive supportive care decisions
- •Mares treated with this technique have low recurrence rates (1-3%), making it a reliable surgical option that avoids complications associated with linea alba adhesions
- •VEGF upregulation in large colon volvulus may be a protective mechanism for early intestinal healing but also contributes to increased vascular permeability and tissue edema
- •IGF pathway activation in small intestine during ischemia-reperfusion suggests potential therapeutic targets to improve outcomes after small intestinal surgical correction
- •Monitoring mRNA expression patterns of growth factors could provide insight into prognosis and guide post-operative management strategies in horses recovering from large colon volvulus
- •Modify stall management and feeding practices—avoid meal feeding and prolonged confinement to reduce alterations in colonic water movement and microbiome disruption
- •Implement surveillance-based parasite control rather than relying solely on anthelmintic efficacy, as large strongyle resistance patterns are changing
- •Tailor management recommendations based on colic type; different conditions (impaction vs. volvulus vs. lipoma) require different nutritional and management strategies
Key Research Findings
Dexmedetomidine preconditioning reduced crypt epithelial loss severity (DEX 2.1 vs CON 3.1, p=0.03) compared to saline control
Mucosal haemorrhage was decreased in dexmedetomidine group (DEX 2.1 vs CON 3.5, p=0.03)
Crypt length remained significantly longer in dexmedetomidine group during reperfusion (369.5±91.7 μm vs 238.5±72.6 μm, p=0.02)
Interstitium to crypt ratio was lower in dexmedetomidine group (DEX 1.4 vs CON 2.6, p=0.03), indicating less mucosal oedema
Post-operative reflux occurred in 18% (23/128) of horses following large colon volvulus surgery despite absence of small intestinal lesions
Horses with post-operative reflux had 26-fold higher odds of non-survival to hospital discharge (44% vs 95% survival; p<0.001)
Post-operative reflux horses had 13.4-fold higher odds of mortality within 3 years post-surgery (p<0.001)
Overall survival rate to hospital discharge was 86% in the LCV cohort, with post-operative reflux identified as a strong negative prognostic indicator
Peripheral venous lactate ≥3.2 mmol/L at admission and ≥5 mmol/L after manual correction were associated with poor short-term outcome
Arterial lactate ≥3.53 mmol/L post-correction and mucosal hemorrhage score ≥3 predicted poor prognosis
Interstitium to crypt ratio >1 was associated with poor short-term survival
Colonic venous lactate values showed no significant association with outcome (P=0.011 before, P=0.201 after correction)
Intestinal progenitor cell biomarkers can be used to identify subpopulations critical for epithelial repair following ischaemic injury in large colon volvulus
A critical number of intestinal progenitor cells determined by protein biomarker expression predicts tissue viability in large colon volvulus cases
Progenitor cell status correlates with survival to discharge in equine large colon volvulus
Evidence Base
Dexmedetomidine preconditioning reduces ischaemia-reperfusion injury in equine model of large colon volvulus.
Watkins Amanda, Engiles Julie, Long Alicia et al. (2024) — Equine veterinary journal
Factors associated with development of post-operative reflux in horses with large colon volvulus and association with complications and outcomes.
Watrobska Natalia, Gough Rachel, Hallowell Gayle et al. (2024) — Equine veterinary journal
Prognostic value of colonic and peripheral venous lactate measurements in horses with large colon volvulus.
Orr Kindra E, Baker W True, Lynch Tim M et al. (2020) — Veterinary surgery : VS
Protein biomarker of cell proliferation determines survival to discharge in cases of equine large colon volvulus.
Kucera C R, Stranahan L W, Hughes F et al. (2018) — Equine veterinary journal
Duration of disease influences survival to discharge of Thoroughbred mares with surgically treated large colon volvulus.
Hackett E S, Embertson R M, Hopper S A et al. (2015) — Equine veterinary journal
Operative factors associated with short-term outcome in horses with large colon volvulus: 47 cases from 2006 to 2013.
Gonzalez L M, Fogle C A, Baker W T et al. (2015) — Equine veterinary journal
Changes in the faecal microbiota of mares precede the development of post partum colic.
Weese J S, Holcombe S J, Embertson R M et al. (2015) — Equine veterinary journal
Surgical treatment of equine colic - a retrospective study of 297 surgeries in Norway 2005–2011
Bjørn Wormstrand, C. Ihler, Ragnhild Diesen et al. (2014) — Acta Veterinaria Scandinavica
Use of physiologic and arterial blood gas variables to predict short-term survival in horses with large colon volvulus.
Kelleher Maureen E, Brosnan Robert J, Kass Philip H et al. (2013) — Veterinary surgery : VS
Risk factors for large colon volvulus in the UK.
Suthers J M, Pinchbeck G L, Proudman C J et al. (2013) — Equine veterinary journal
Use of colonic luminal pressure to predict outcome after surgical treatment of strangulating large colon volvulus in horses.
Mathis Stephanie C, Slone Donnie E, Lynch Timothy M et al. (2006) — Veterinary surgery : VS
Prevalence of gastric squamous ulceration in horses with abdominal pain.
Dukti S A, Perkins S, Murphy J et al. (2006) — Equine veterinary journal
Small Colon Faecalith with Large Colon Displacement in Ten Cases (2015-2023): A Detailed Case Description and Literature Review.
Scilimati Nicola, Cerullo Anna, Nannarone Sara et al. (2024) — Animals : an open access journal from MDPI
Flowmetry and spectrophotometry can detect reduced intestinal microperfusion in nonsurvivors during equine colic surgery for large intestinal strangulation
Verhaar Nicole, Reineking Wencke, Hewicker-Trautwein Marion et al. (2024) — American Journal of Veterinary Research
Large Colon Volvulus in a Neonatal Foal Secondary to Atresia Coli.
McGovern K F, Gough R L (2022) — Journal of equine veterinary science
Gastric and Large Colon Impactions Combined With Aggressive Enteral Fluid Therapy May Predispose to Large Colon Volvulus: 4 Cases.
Giusto Gessica, Cerullo Anna, Gandini Marco (2021) — Journal of equine veterinary science
Expression of Proteinase-Activated Receptor 2 During Colon Volvulus in the Horse.
Lambertini Carlotta, Zannoni Augusta, Romagnoli Noemi et al. (2020) — Frontiers in veterinary science
Clinical outcomes after colopexy through left ventral paramedian incision in 156 thoroughbred broodmares with large colon disorders (1999-2015).
Broyles Alecsya H, Hopper Scott A, Woodie J Brett et al. (2018) — Veterinary surgery : VS
Growth factor and receptor mRNA expression in the intestine of horses with large colon volvulus: a pilot study.
Southwood L L, Lindermann J, Zarucco L et al. (2006) — Equine veterinary journal
Colic Prevention to Avoid Colic Surgery: A Surgeon's Perspective.
Blikslager Anthony T (2019) — Journal of equine veterinary science