Coagulation Disorders, DIC, and Organ Dysfunction in Equine Colic: Emerging Prognostic Insights

Colic remains one of the most common and life-threatening conditions encountered in equine practice and continues to be a major cause of mortality worldwide. Increasing evidence suggests that severe colic is not merely a gastrointestinal disorder but is also associated with systemic coagulation abnormalities, fibrinolysis, and multiorgan dysfunction¹. 

These systemic alterations may significantly influence survival outcomes but are often under-recognized during early clinical evaluation. 

Why Coagulation Matters in Colic 

The pathogenesis of severe colic involves activation of inflammatory and coagulation pathways, which may progress to disseminated intravascular coagulation (DIC)¹. In horses with advanced gastrointestinal disease, abnormalities such as thrombocytopenia, prolonged prothrombin time (PT), increased fibrin degradation products (PDD/d-dimer), reduced fibrinogen concentrations, and altered antithrombin activity have all been associated with hypercoagulability and poor prognosis¹. 

In practical terms, severe colic is not simply an intestinal disorder—it can rapidly become a systemic vascular disease. 

DIC and Microvascular Damage 

DIC is characterized by uncontrolled coagulation and fibrinolysis occurring simultaneously, resulting in widespread fibrin microthrombi formation within small blood vessels². 

The consequences include: 

• Reduced tissue perfusion 

• Hypoxic cellular injury 

• Organ dysfunction 

• Multiorgan failure 

Vital organs commonly affected include: 

• Kidneys 

• Liver 

• Lungs 

• Heart 

• Central nervous system 

Microvascular fibrin deposition has been linked with organ dysfunction in horses with gastrointestinal disorders and is considered consistent with DIC-related pathology². 

In severe colic cases, organ dysfunction may therefore result not only from dehydration or endotoxemia, but also from microvascular thrombosis. 

Clinical Examination: Useful but Often Incomplete 

Routine clinical examination remains essential in colic evaluation. Parameters commonly assessed include¹: 

• Heart rate (HR) 

• Capillary refill time (CRT) 

• Respiratory rate (RR) 

• Abdominal sounds 

• Nasogastric reflux 

• Rectal findings 

• Body temperature 

• Abdominocentesis findings 

However, evidence suggests that some traditionally emphasized findings may not reliably predict survival when interpreted alone. 

Clinical Parameters with Better Prognostic Value 

The parameters most consistently associated with poorer outcomes include: 

Heart Rate (HR) 

Higher HR strongly correlates with nonsurvival and reflects pain severity, hypovolemia, and systemic compromise^1,3. 

Capillary Refill Time (CRT) 

Prolonged CRT has been associated with poorer prognosis and circulatory compromise¹. 

Abdominal Sound Status 

Reduced gut sounds have been linked with severe disease progression and worsening gastrointestinal motility disturbances^1,4. 

These findings demonstrate stronger prognostic utility compared to several other routine examination parameters. 

Parameters with Limited Predictive Accuracy 

Several commonly used clinical findings may have limited ability to independently differentiate survivors from nonsurvivors. 

These include¹: 

• Rectal palpation findings 

• Nasogastric reflux volume 

• Body temperature 

• Abdominocentesis findings 

Studies have shown that reliance solely on rectal findings or gastric reflux may occasionally delay appropriate surgical intervention or result in inaccurate prognostic assessment (White et al., 2005). 

This highlights an important clinical reality: relying solely on examination findings may delay appropriate surgical referral or aggressive intervention. 

Role of Hematology and Biochemical Markers 

Routine blood parameters provide additional prognostic value. 

Hemoconcentration 

Nonsurviving horses frequently demonstrate: 

• Increased RBC count 

• Elevated hematocrit (HCT) 

• Higher hemoglobin concentrations 

These changes reflect severe dehydration, acute intestinal fluid shifts, and reduced perfusion¹. 

Renal and Hepatic Dysfunction in Severe Colic 

Significant increases in¹: 

• Urea 

• Creatinine 

• Total bilirubin 

• AST activity 

have been associated with¹: 

• Renal dysfunction 

• Hepatic compromise 

• Prerenal azotemia secondary to dehydration and hypoperfusion 

However, evidence also suggests that organ injury may result from fibrin microthrombi associated with DIC rather than dehydration alone. 

Severe colic should therefore be viewed as a potential multiorgan disease process. 

Key Coagulation Findings Associated with Poor Prognosis 

Horses with poorer outcomes commonly demonstrate: 

• Prolonged PT 

• Increased fibrin degradation products (PDD/d-dimer) 

• Reduced fibrinogen concentration 

When multiple coagulation abnormalities occur simultaneously, subclinical DIC becomes highly likely^1,2. 

Combined abnormalities in coagulation parameters have shown strong association with poor survival outcomes, emphasizing the importance of coagulation profiling in severe colic cases¹. 

Hypofibrinogenemia: An Important Red Flag 

Marked hypofibrinogenemia in severe colic may reflect: 

• Excessive fibrinolysis 

• Consumptive coagulopathy associated with DIC 

The combination of: 

• Low fibrinogen 

• Increased PDD/d-dimer 

• Prolonged PT 

is considered particularly concerning and may indicate advanced systemic involvement¹. 

Clinical Relevance  

Clinical examination alone may not always accurately predict outcomes in horses with colic, as severe cases can involve systemic coagulation disturbances and disseminated intravascular coagulation (DIC). Early coagulation profiling may therefore support faster and more informed treatment decisions, particularly in identifying horses at risk of poor prognosis. Organ dysfunction involving the kidneys and liver may reflect DIC-related microvascular injury and impaired tissue perfusion. Studies indicate that combining clinical findings with laboratory markers provides better prognostic accuracy than relying on physical examination alone. Among the most useful parameters are heart rate, capillary refill time (CRT), gut sounds, prothrombin time (PT), fibrinogen concentration, plasma degradation products (PDD/d-dimer), and renal and hepatic biomarkers 

References  

1. Nikvand AA, Jalali SM, Ghadrdan Mashhadi A, Razi Jalali M, Hassanpour Amirabadi S. Clinical, hematologic, hemostatic, and serum biochemical findings related to survival in Arabian horses with colic. Veterinary clinical pathology. 2019 Sep;48(3):441-8. https://doi.org/10.1111/vcp.12779  

2. Monreal L, Anglés A, Espada Y, Monasterio J, Monreal M. Hypercoagulation and hypofibrinolysis in horses with colic and DIC. Equine Veterinary Journal. 2000 Jun;32(S32):19-25. https://doi.org/10.1111/j.2042-3306.2000.tb05329.x  

3. Nocera I, Cingottini D, Di Franco C, Sala G, Bindi F, Spadari A, Rinnovati R, Vitale V, Jose-Cunilleras E, Sgorbini M. In-Depth Analysis of the Prognostic Factors Associated with Short-Term Outcome in Equine Colic Patients: Multicentric Retrospective Study. Animals. 2026 Jan;16(3):496. https://www.mdpi.com/2076-2615/16/3/496 

4. Fereig RM. A review on equine colic: Etiology, differential diagnosis, therapy, and prevention. Ger J Vet Res. 2023;3(4):1-2. https://gmpc-akademie.de/articles/1702196798_2023_4_0063_GJVR_Freig.pdf