Background: Septicemia is associated with a systemic inflammatory response, hemostatic activation, and disseminated intravascular coagulopathy (DIC).Hypothesis: Increased plasma D-dimer concentration occurs in septic neonates and can reliably detect sepsis or DIC, and predict death in ill neonatal foals.Animals: 40 septic, 41 nonseptic hospitalized foals, and 22 healthy neonates. Methods: Prospective observational clinical study. Blood samples were collected on admission, at 24-48 hours after admission, and at the time of discharge or euthanasia. Plasma D-dimer concentration, clotting times, antithrombin activity, and fibrinogen concentration were determined.Results: On admission, D-dimer concentration values were significantly higher in septic foals (median, 25-75th percentiles; 568, 245-2013 ng/mL) compared with the nonseptic and healthy groups (386, 175-559 and 313, 152-495 ng/mL, respectively), and in septic foals at the age of 2-7 days compared with similar-age nonseptic foals. By means of samples taken at 24-48 hours of hospitalization and a cut-off value of 4 2000 ng/mL, D dimer concentration was significantly associated with the diagnosis of septicemia (odds ratio [OR] 5 19.6, 95% confidence interval [95% CI] 1.9-203) and death (OR 5 8.7, 95% CI 1.8-43). Owing to a high false-positive prediction rate (71%), a normal D-dimer concentration is better at eliminating the diagnosis of sepsis than an increased D-dimer concentration at predicting sepsis. Fifty percent of septic foals had a diagnosis of DIC, but D-dimer concentration was not significantly associated with the diagnosis of DIC.Conclusions and clinical importance: Septic foals showed a marked activation of coagulation and fibrinolytic systems and a high prevalence of DIC. Increased plasma D-dimer concentration is significantly associated with the diagnosis of sepsis.

Background: Coagulopathies detected in horses with gastrointestinal problems seem to be associated with poor outcome. Plasma D-Dimer concentration is a sensitive test for assessing coagulopathies.Hypothesis: Plasma D-Dimer concentration tested on admission is related to diagnosis and outcome in horses with colic. Animals: Four hundred and ninety three horses referred for evaluation of abdominal pain. Methods: Prospective observational clinical study. Horses were grouped according to diagnosis (medical and surgical intestinal obstructions, ischemic disorders with and without intestinal resection, enteritis, peritonitis), outcome (survivors, nonsurvivors), and number of coagulopathies (normal profile, 1 or 2 coagulopathies, subclinical disseminated intravascular coagulation [DIC]). Blood samples were collected on admission and plasma D-Dimer concentration, clotting times (PT and aPTT), and antithrombin activity were determined. Positive likelihood ratios (LR1) were calculated for evaluation of D-Dimer cut-off values, which were later tested in a logistic regression model.Results: Horses with enteritis or peritonitis had significantly (P o .001) higher plasma D-Dimer concentrations and more severe coagulopathies on admission than horses with other diagnoses. Nonsurvivors also had significantly (P o .001) higher plasma D-Dimer concentrations at presentation than did survivors, and those horses with subclinical DIC on presentation had an odds ratio (OR) 8.6 (95% confidence interval [CI], 3.3-22.5, P o .001) for nonsurvival. Finally, D-Dimer concentrations 44,000 ng/mL had a LR1 of 5.9 and an OR 8.8 (95% CI, 4.5-17.1, P o .001) for nonsurvival.Conclusion and Clinical Importance: Plasma D-Dimer concentration measured on admission can be used to facilitate diagnosis and outcome prediction in horses with colic. A potential cut-off value for nonsurvival was found at approximately 4,000 ng/mL.

Peritoneal D-dimer concentration is markedly higher in severe GI disorders, and it can be used to assess peritoneal fibrinolytic activity in horses with colic.

Background: Increased synovial fibrinolytic activity (detected by increases in synovial D-Dimer concentrations) has been observed in different joint diseases in humans and adult horses, presumably in order to minimize fibrin deposition within the joint and thus avoid its detrimental effects.Objective: To investigate fibrinolytic pathway activation in joint sepsis in foals by measuring synovial D-Dimer concentrations.Animals: Eighteen septic foals with septic joints, 9 septic foals without septic joints, 9 systemically healthy foals with septic joint, and 3 controls are included.Methods: Prospective observational clinical study of foals admitted for septic arthritis. Synovial D-Dimer concentration and routine synovial fluid analysis were performed. Diagnosis of joint sepsis was made whenever synovial total nucleated cell count was 430,000 cells/mL, synovial total protein 44 g/dL, and neutrophil percentage of 480%, or synovial fluid culture resulted positive. Results were compared among groups by general lineal models.Results: Synovial D-Dimer concentration was significantly (P o .001) higher in the foals with septic joints compared with foals without joint disease (P o .001).Conclusions and Clinical Importance: Septic joint disease is associated with a marked increase of synovial D-Dimer concentration (marked activation of the fibrinolytic activity) within the affected joint. Although further studies are needed, the measurement of synovial D-Dimer concentration may be considered a complementary diagnostic marker of septic joint disease.