Comparison of empirically developed sepsis score with a computer generated and weighted scoring system for the identification of sepsis in the equine neonate

Clinical predictive models in equine medicine: A systematic review

Clinical predictive models use a patient's baseline demographic and clinical data to make predictions about patient outcomes and have the potential to aid clinical decision making. The extent of equine clinical predictive models is unknown in the literature. Using PubMed and Google Scholar, we systematically reviewed the predictive models currently described for use in equine patients. Models were eligible for inclusion if they were published in a peer-reviewed article as a multivariable model used to predict a clinical/laboratory/imaging outcome in an individual horse or herd. The agreement of at least two authors was required for model inclusion. We summarised the patient populations, model development methods, performance metric reporting, validation efforts, and, using the Predictive model Risk of Bias Assessment Tool (PROBAST), assessed the risk of bias and applicability concerns for these models. In addition, we summarised the index conditions for which models were developed and provided detailed information on included models. A total of 90 predictive models and 9 external validation studies were included in the final systematic review. A plurality of models (41%) was developed to predict outcomes associated with colic, for example, need for surgery or survival to discharge. All included models were at high risk of bias, defined as failing one or more PROBAST signalling questions, primarily for analysis-related reasons. Importantly, a high risk of bias does not necessarily mean that models are unusable, but that they require more careful consideration prior to clinical use. Concerns about applicability were low for the majority of models. Systematic reviews such as this can serve to increase veterinarians' awareness of predictive models, including evaluation of their performance and their use in different patient populations.

Serum amyloid A as a marker to detect sepsis and predict outcome in hospitalized neonatal foals

BACKGROUND

Serum amyloid A (SAA) has been reported to hold promise as diagnostic and prognostic marker in foals. This has not been investigated thoroughly.

OBJECTIVES

Evaluate admission SAA concentrations as predictor of sepsis and outcome.

ANIMALS

Five hundred and ninety hospitalized foals <14 days old.

METHODS

Retrospective multicenter study. Foals were scored with sepsis and survival scores, grouped according to health category (septic, sick but nonseptic, uncertain sepsis status) and outcome; septic foals were further categorized according to severity (normal sepsis, severe sepsis, and septic shock). SAA was compared between groups using Mann-Whitney test and Kruskal-Wallis test. Receiver operating characteristic curves identified optimal SAA cut off values for detecting sepsis and predicting outcome.

RESULTS

Admission SAA concentrations differed significantly between sick nonseptic foals (312.1 ± 685.4 mg/L) and septic foals (1079.7 ± 1254.5 mg/L) and increased with increasing sepsis score. SAA did not differ between sepsis severity groups. The optimal cut off for sepsis detection was 1050 mg/L (sensitivity 30.2%, specificity 90.7%). Admission SAA concentrations were lower in surviving (435.0 ± 723.6 mg/L) compared to nonsurviving foals (1062.7 ± 1440.1 mg/L) and decreased with increasing survival score. The optimal cut off for nonsurvival prediction was 1250 mg/L (sensitivity 22.1%, specificity 90.8%).

CONCLUSIONS AND CLINICAL IMPORTANCE

SAA concentration was higher in septic foals and nonsurviving foals. Even though optimal cut offs for SAA to detect sepsis and predict outcome had low sensitivity, they had good specificity. SAA can therefore be used as a marker to rule out sepsis and nonsurvival.

Equine blood cultures: Can we do better?

Blood culture is considered the gold standard test for documenting bacteraemia in patients with suspected bacterial sepsis in veterinary and human medicine. However, blood culture often fails to yield bacterial growth even though the clinical picture is strongly suggestive of bacterial sepsis, or contaminating organisms can overgrow the true pathogen, making accurate diagnosis and appropriate management of this life-threatening condition very challenging. Methodology for collecting blood cultures in equine medicine, and even in human hospitals, is not standardised, and many variables can affect the yield and type of microorganisms cultured. Microbiological culture techniques used in the laboratory and specific sample collection techniques, including volume of blood collected, aseptic technique utilised, and the site, timing and frequency of sample collection, all have substantial impact on the accuracy of blood culture results. In addition, patient-specific factors such as husbandry factors, the anatomical site of the primary infection, and changing microflora in different geographic locations, also can impact blood cultures. Thus, blood cultures obtained in practice may not always accurately define the presence or absence of, or specific organisms causing, bacteraemia in horses and foals with suspected sepsis. Erroneous blood culture results can lead to inappropriate antimicrobial use, which can result in poor outcomes for individual patients and contribute to the development of antimicrobial resistance in the patient's microflora and the environmental microcosm. This review summarises current indications and methodology, and specific factors that may be optimised, for equine blood culture, with particular focus on available literature from neonatal foals with suspected bacterial sepsis. To standardise and optimise blood culture techniques in horses and foals, future research in this area should be aimed at determining the optimal volume of blood that should be collected for culture, and the ideal site, timing, and frequency of sample collection.

Equine simplified acute physiology score: Personalised medicine for the equine emergency patient

BACKGROUND

Scoring models are useful tools that guide the attending clinician in gauging the severity of disease evolution and in evaluating the efficacy of treatment. There are few tools available with this purpose for the non-human patient, including horses. We aimed (i) to adapt the simplified acute physiology score 3 (SAPS-3) model for the equine species, reaching a margin of accuracy greater than 75% in the calculation of the probability of survival/death and (ii) to build a decision tree that helps the attending veterinarian in assessment of the clinical evolution of the equine patient.

METHODS

From an initial pool of 5568 medical records from University-based Veterinary Hospitals, a final cohort of 1000 was further mined manually for data extraction. A set of 19 variables were evaluated and tested by five machine learning data mining algorithms.

RESULTS

The final scoring model, named EqSAPS for equine simplified acute physiology score, reached 91.83% of correct estimates (post hoc) for probability of death within 24 hours upon hospitalization. The area under receiver operating characteristic curve for outcome 'death' was 0.742, while for 'survival' was 0.652. The final decision tree was able to refine prognosis of patients whose EqSAPS score suggested 'death'.

CONCLUSION

EqSAPS is a useful tool to gauge the severity of the clinical presentation of the equine patient.

[Uroperitoneum in neonatal foals - a review of the literature]

Uroperitoneum is a typical disease in newborn foals. An accumulation of urine develops in the abdominal cavity in consequence to a congenital or acquired leakage in the urinary tract. Colts are more frequently affected than fillies. The most common cause of uroperitoneum is a rupture of the dorsal urinary bladder wall. The urinary bladder is affected in 73.1 %, the urachus in 21.6 % and the ureter in 5.2 % of cases. Typical clinical signs occur 2-5 days postpartum, and encompass reduced general condition, abdominal distention, mild colic symptoms and unphysiologic micturition. Ultrasound examination in conjunction with abdominocentesis is considered as the gold standard of diagnostics. Typical laboratory findings are azotemia, metabolic acidosis as well as electrolyte imbalances, particularly hyperkalemia, hyponatriemia and hypochloridemia. Surgical treatment is the only reasonable therapy. Preoperative metabolic disorders and electrolyte abnormalities should be corrected prior to surgery. Especially hyperkalemia leads to a high potential for complications during general anesthesia. Following effective perioperative stabilization, the presence of a defect in the bladder wall or the urachus carries a good prognosis. In total, 63.6 % of the affected foals are healed. Most common complication is a recurrence of uroperitoneum caused by disruption of the suture line or an incomplete closure of the defect.

Third Generation Cephalosporin Resistant Enterobacterales Infections in Hospitalized Horses and Donkeys: A Case-Case-Control Analysis

In human medicine, infections caused by third-generation cephalosporin-resistant Enterobacterales (3GCRE) are associated with detrimental outcomes. In veterinary medicine, controlled epidemiological analyses are lacking. A matched case–case–control investigation (1:1:1 ratio) was conducted in a large veterinary hospital (2017–2019). In total, 29 infected horses and donkeys were matched to 29 animals with third-generation cephalosporin-susceptible Enterobacterales (3GCSE) infections, and 29 uninfected controls (overall n = 87). Despite multiple significant associations per bivariable analyses, the only independent predictor for 3GCRE infection was recent exposure to antibiotics (adjusted odds ratio (aOR) = 104, p < 0.001), but this was also an independent predictor for 3GCSE infection (aOR = 22, p < 0.001), though the correlation with 3GCRE was significantly stronger (aOR = 9.3, p = 0.04). In separated multivariable outcome models, 3GCRE infections were independently associated with reduced clinical cure rates (aOR = 6.84, p = 0.003) and with 90 days mortality (aOR = 3.6, p = 0.003). Klebsiella spp. were the most common 3GCRE (36%), and bla_CTX-M-1 was the major β-lactamase (79%). Polyclonality and multiple sequence types were evident among all Enterobacterales (e.g., Klebsiella pneumoniae, Escherichia coli, Enterobacter cloacae). The study substantiates the significance of 3GCRE infections in equine medicine, and their independent detrimental impact on cure rates and mortality. Multiple Enterobacterales genera, subtypes, clones and mechanisms of resistance are prevalent among horses and donkeys with 3GCRE infections.

Factors associated with the risk of positive blood culture in neonatal foals presented to a referral center (2000-2014)

Background

Bloodstream infections (BSI) are common in sick foals and increase foal morbidity and mortality when they occur. Recognition of risk factors for BSI could be an important means to limit their occurrence, but studies on this topic are limited.

Objectives

Historical as well as maternal and foal physical examination findings will predict risk of BSI in neonatal foals.

Animals

Foals <14 days of age admitted to a referral equine hospital for care.

Methods

Retrospective case‐control study with univariate and multivariable logistic regression analysis.

Results

Four hundred twenty‐nine (143 cases and 286 controls) foals <14 days of age were studied. Risk of a foal having a BSI was increased in foals with umbilical disease (adjusted odds ratio [OR], 11.01; P = .02), hypoglycemia (adjusted OR, 13.51; P = .03), and the combined presence of umbilical disease and low hematocrit (adjusted OR, >999.99; P = .04). Factors not found to be risk factors for development of BSI included prematurity, hypothermia, abdominal disease, diarrhea, failure of passive transfer, and maternal uterine infection.

Conclusions and Clinical Importance

Several historical and physical examination findings increase the risk of foals being blood culture positive at presentation to the hospital. This knowledge may aid early identification of blood culture status, thus aiding in treatment decisions.

Extended-Spectrum β-Lactamase-Producing Enterobacteriaceae in Hospitalized Neonatal Foals: Prevalence, Risk Factors for Shedding and Association with Infection

Simple Summary

Multidrug-resistant (MDR) Enterobacteriaceae are becoming a major worldwide concern in human and veterinary medicine, mainly due to the production of extended-spectrum β-lactamases (ESBLs). These bacteria have been investigated in adult horses, but not in neonatal foals. In this study, we investigated extended-spectrum β-lactamase Enterobacteriaceae (ESBL-E) shedding and infection in hospitalized mares and their neonatal foals. Overall, we sampled rectal swabs from 55 pairs of mares and their foals on admission, and 33 of them were re-sampled on the 3rd day of hospitalization. We also collected clinical samples, when available. We found that shedding rates and bacterial species diversity increased significantly during hospitalization, both in mares and foals. On admission to hospital, foals’ shedding was associated with umbilical infection. During hospitalization, it was associated with ampicillin treatment. Foals’ shedding was independent of their mares’ shedding. Four foals were infected with ESBL-E strains, including umbilical infections and wounds. We suggest further investigation and surveillance of ESBL-E in neonatal foals, in order to reduce resistance rates and infections.

Abstract

Extended-spectrum β-lactamase Enterobacteriaceae (ESBL-E) have been investigated in adult horses, but not in foals. We aimed to determine shedding and infection in neonatal foals and mares. Rectal swabs were sampled from mare and foal pairs on admission and on the 3rd day of hospitalization; enriched, plated, and bacteria were verified for ESBL production. Identification and antibiotic susceptibility profiles were determined (Vitek2). Genotyping was performed by multilocus sequence typing (MLST). Genes were identified by PCR and Sanger sequencing. Medical data were analyzed for risk factors (SPSS). On admission, 55 pairs were sampled, of which 33 pairs were re-sampled. Shedding rates on admission in foals and mares were 33% (95% CI 21–47%) and 16% (95% CI 8–29%), respectively, and during hospitalization, these increased significantly to 85% (95% CI 70–94%) and 58% (95% CI 40–73%), respectively. Foal shedding was associated with umbilical infection on admission (P = 0.016) and with ampicillin treatment during hospitalization (p = 0.011), and was independent of the mare’s shedding. The most common ESBL-E was Escherichia coli. During hospitalization, species diversity increased. Four foals were infected with ESBL-E strains, including umbilical infections and wounds. This study substantiates an alarming prevalence of shedding in neonatal foals, which should be further investigated in order to reduce resistance rates.

A Comparative Review of Equine SIRS, Sepsis, and Neutrophils

The most recent definition of sepsis in human medicine can be summarized as organ dysfunction caused by a dysregulated host response to infection. In equine medicine, although no consensus definition is available, sepsis is commonly described as a dysregulated host systemic inflammatory response to infection. Defense against host infection is the primary role of innate immune cells known as neutrophils. Neutrophils also contribute to host injury during sepsis, making them important potential targets for sepsis prevention, diagnosis, and treatment. This review will present both historical and updated perspectives on the systemic inflammatory response (SIRS) and sepsis; it will also discuss the impact of sepsis on neutrophils, and the impact of neutrophils during sepsis. Future identification of clinically relevant sepsis diagnosis and therapy depends on a more thorough understanding of disease pathogenesis across species. To gain this understanding, there is a critical need for research that utilizes a clearly defined, and consistently applied, classification system for patients diagnosed with, and at risk of developing, sepsis.

The FGF-23/klotho axis and its relationship with phosphorus, calcium, vitamin D, PTH, aldosterone, severity of disease, and outcome in hospitalised foals

BACKGROUND

Fibroblast growth factor-23 (FGF-23) and klotho are key regulators of vitamin D and parathyroid hormone (PTH) synthesis as well as phosphorus and calcium homeostasis; however, information on the FGF-23/klotho axis in healthy and hospitalised foals is lacking.

OBJECTIVES

The aims of this study were to measure serum FGF-23 and klotho concentrations and determine their association with serum phosphorus, total calcium (TCa), vitamin D metabolite [25(OH)D, 1,25(OH)₂ D], PTH, and aldosterone concentrations, disease severity, and mortality in hospitalised foals.

STUDY DESIGN

Prospective, multicentre, cross-sectional study.

METHODS

A total of 91 foals ≤72 h old were classified as hospitalised (n = 81; 58 septic; 23 sick non-septic [SNS]) and healthy (n = 10). Blood samples were collected on admission. Hormone concentrations were determined by immunoassays.

RESULTS

Serum FGF-23, PTH, phosphorus, and aldosterone concentrations were higher while klotho, 25(OH)D, 1,25(OH)₂ D, and TCa concentrations were lower in septic and SNS compared to healthy foals (P<0.05). In hospitalised and septic foals, increased FGF-23 and aldosterone concentrations were associated with high phosphorus and PTH but not with TCa and vitamin D metabolite concentrations. Hospitalised foals with the highest FGF-23 and lowest klotho concentrations were more likely to die (odds ratio (OR): 3.3; 95% confidence interval (CI): 1.1-10.3 and OR: 3.1; CI: 1.1-8.0, respectively).

MAIN LIMITATIONS

Blood gas, ionised calcium, blood culture information not being available for many foals, and use of the sepsis score to classify hospitalised foals.

CONCLUSIONS

Imbalances in the FGF-23/klotho axis may contribute to mineral dyshomeostasis and disease progression in critically ill foals. Elevated FGF-23 and reduced klotho, together with high phosphorus and PTH concentrations suggests FGF-23 resistance. FGF-23 and klotho are good markers of disease severity and likelihood of mortality in hospitalised foals. Aldosterone may influence phosphorus and PTH dynamics in hospitalised foals. Routine measurement of phosphorus concentrations in sick foals is recommended.

Evaluation of updated sepsis scoring systems and systemic inflammatory response syndrome criteria and their association with sepsis in equine neonates

Background

The original equine sepsis score provided a method of identifying foals with sepsis. New variables associated with sepsis have been evaluated, but the sepsis score has not been updated.

Objectives

To evaluate the sensitivity and specificity of 2 updated sepsis scores and the systemic inflammatory response syndrome (SIRS) criteria in regard to detecting sepsis in foals.

Animals

Two‐hundred and seventy‐three ill foals and 25 healthy control foals.

Methods

Historical, physical examination, and clinicopathologic findings were used to calculate the original sepsis score and 2 updated sepsis scores. SIRS criteria were also evaluated. Sepsis scores and positive SIRS scores were statistically compared to foals with sepsis.

Results

One‐hundred and twenty‐six foals were septic and 147 sick‐nonseptic. The original and updated sepsis scores were significantly higher in septic foals as compared to sick‐nonseptic and healthy foals. The sensitivity and specificity of the updated sepsis scores to predict sepsis were not significantly better than those of the original sepsis score. One‐hundred and twenty‐seven of 273 (46.5%) foals met the original SIRS criteria and 88/273 (32%) foals met the equine neonatal SIRS criteria. The original SIRS criteria had similar sensitivity and specificity for predicting sepsis as did the 3 sepsis scores in our study.

Conclusions and Clinical Importance

The updated sepsis scores did not provide improved ability in predicting sepsis. Fulfilling the original SIRS criteria provided similar sensitivity and specificity in predicting sepsis as the modified sepsis score and might serve as a diagnostic aid in identifying foals at risk for sepsis.

Treatment of septic arthritis of the coxofemoral joint in 12 foals

OBJECTIVE

To describe the clinical signs, surgical treatment, and outcome of septic arthritis of the coxofemoral joint in foals.

STUDY DESIGN

Retrospective clinical study.

SAMPLE POPULATION

Foals (n = 12) with confirmed sepsis of the coxofemoral joint.

METHODS

Lameness was localized to the coxofemoral joint based on physical examination. Sepsis was confirmed by cytological analysis of synovial fluid obtained under ultrasonographic guidance, during general anesthesia or standing sedation. Intra-articular analgesia was used as an adjunct diagnostic modality in 2 foals. Surgical lavage of the affected joint was performed via arthroscopy or needle lavage, with repeated lavage performed in 7 foals.

RESULTS

Synovial fluid contained 4.4 to 173 × 10⁹ /L white blood cells (WBCs), and 38-63 g/L total protein. Cultures were positive in 10/12 foals. Isolated organisms included Salmonella spp., Streptococcus spp., Rhodococcus spp., Enterococcus spp., Escherichia spp., Staphylococcus spp., Acinetobacter spp., Methicillin-resistant Staphylococcus aureus and Bacillus spp. Ten foals were discharged from hospital (83%). One of these was euthanized 15 days later due to chronic intestinal salmonellosis and renal failure, and 9 foals survived with no residual lameness detected 1 year after discharge from hospital.

CONCLUSIONS

Sepsis of the coxofermoral joint can be effectively treated with a combination of arthroscopic lavage and the use of systemic and local antimicrobials.

Factors associated with outcome and gradual improvement in survival over time in 1065 equine neonates admitted to an intensive care unit

REASONS FOR PERFORMING STUDY

There is a paucity of information regarding the association between common disorders and outcome over time in a large population of ill equine neonates.

OBJECTIVES

To describe the relative frequency of neonatal disorders in a large population of foals admitted to a neonatal intensive care unit, to determine the disorders and factors associated with nonsurvival and determine if the outcome of ill neonatal foals has improved over time.

STUDY DESIGN

Retrospective study.

METHODS

Cases were selected from equine neonatal (≤14 days of age) admissions between 1982 and 2008. Multivariable logistic regression was used to identify the disorders, clinical parameters and laboratory variables associated with nonsurvival or natural death and assess survival over time after accounting for potential confounding variables.

RESULTS

A total of 1065 foals were included in the study. Overall, 775 of 1065 (72.8%) foals survived to be discharged from the hospital and 290 (27.2%) foals were nonsurvivors. Age at admission, sepsis score, proportion of foals with positive blood cultures and proportion of survivors were significantly different (P<0.001) between primary disease categories. Variables retained in the multivariable model for nonsurvival included positive blood culture, neutrophils <2.28 × 10⁹ /l, temperature ≤37.6°C, bicarbonate, PCO₂ , presence of infectious orthopaedic disorders and sepsis score. The adjusted odds of survival for foals admitted in the 2000s were approximately 3.4 (95% CI = 1.9-6.0, P<0.001) times higher than that of foals admitted in the 1980s.

CONCLUSIONS

Primary disorders, sepsis, temperature, acid base status and neutropenia are the main factors that affect outcome in this population of equine neonates. The survival of foals admitted to a neonatal intensive care unit has increased dramatically over a 26 year period.

Retrospective evaluation of blood culture isolates and sepsis survival rate in foals in the Czech Republic: 50 cases (2011-2013)

OBJECTIVE

To identify the specific pathogens causing sepsis in hospitalized foals in the Czech Republic and identify important factors associated with their survival.

DESIGN

A retrospective study from 2011 to 2013.

SETTING

University veterinary teaching hospital.

ANIMALS

Fifty compromised foals.

INTERVENTIONS

None.

MEASUREMENT AND MAIN RESULTS

Blood was aseptically collected for bacterial culture from compromised foals. The foals were classified as septic according to a positive blood culture result or sepsis score ≥11. Blood cultures were positive in 44% of the foals. In these positive cultures, 27.3% had only Gram-positive (G+) bacteria and 54.5% had only Gram-negative (G-) bacteria. A mixed bacterial population was presented in 18.2% of the positive cultures. Thirty-six foals were classified as septic on the basis of positive blood culture or a sepsis score ≥11. In the group of foals that did not survive, there were significantly more foals with low levels of immunoglobulin G (IgG) than foals with normal levels of IgG (P < 0.0001). We also found a significant difference in the proportion of foals with low levels of IgG and positive blood cultures when compared to negative blood cultures. Twenty-six of the 50 foals were discharged from the hospital. Survival was significantly lower in foals with a diagnosis of sepsis than in foals without sepsis. There was no statistically significant difference between foals that died as a result of infection caused by G- or G+ pathogens. There was no difference in the proportion of survivors that did or did not receive antimicrobials prior to admission.

CONCLUSIONS

In our study, we confirmed the increasing trend for G+ bacteria in blood cultures but G- still predominate. The percentage of nonsurviving septic foals was high.

Re-evaluation of the sepsis score in equine neonates

REASONS FOR PERFORMING STUDY

The modified sepsis scoring system provides a method to identify sepsis in foals early in the disease process, but inconsistent results have been obtained from its clinical application in previous studies.

OBJECTIVES

To evaluate the sensitivity and specificity of the modified sepsis score in a larger population of foals. A secondary objective was to identify factors associated with sepsis.

STUDY DESIGN

Retrospective cohort study.

METHODS

Records were retrospectively analysed for neonatal admissions to the University of Florida Large Animal Hospital from 1982 to 2008. Backwards stepwise multivariable logistic regression was used to evaluate objective clinical factors associated with sepsis. Receiver operating chararacteristic ROC curve analysis was performed on the modified sepsis score and used to determine an optimal cut point.

RESULTS

A total of 1065 foals were included in the study. The modified sepsis score had a sensitivity of 56.4% and specificity of 73.4% for the originally suggested cut point (>11). Receiver operating chararacteristic analysis revealed an optimal cut point of >7 (sensitivity 84.4%, specificity 41.8%). The modified sepsis score performed better than the generated regression model which included age, creatinine, lymphocytes, potassium and IgG>8 g/l (P = 0.026). Diagnostic performance of the modified sepsis score did not change significantly over time.

CONCLUSIONS

Sensitivity and specificity of the modified sepsis score were not as high as previously documented, but the score still outperformed a regression model derived from objective clinical data. The Summary is available in Chinese - see Supporting information.

Update on the management of neonatal sepsis in horses

Despite advances in neonatal intensive care sepsis, severe sepsis and septic shock remain the biggest killers of neonatal foals. Management of this severe syndrome remains difficult, requiring intensive intervention. Key aspects of management include infection control, hemodynamic support, immunomodulatory interventions, and metabolic/endocrine support. Infection control largely consists of early antimicrobial therapy, plasma transfusions, and local therapy for the infected focus. In cases with severe sepsis or septic shock, hemodynamic support with fluids, vasoactive agents, and respiratory support insuring oxygen delivery to vital organs is important. Nutritional support is important, but close monitoring is needed to avoid hyperglycemia and hypoglycemia.

Uveal inflammation in septic newborn foals

BACKGROUND

Septicemia in humans is described as a leading cause of uveitis, which eventually can induce blindness.

HYPOTHESIS/OBJECTIVES

Uveal inflammatory findings could be related to sepsis severity in newborn foals and might be used as an indirect indicator for survival.

ANIMALS

Seventy-four septic foals, 54 nonseptic foals, and 42 healthy foals.

METHODS

Prospective observational clinical study. A detailed blinded, ophthalmic examination was performed by boarded ophthalmologists on all admitted newborn foals. Foals were grouped as septic (when blood culture resulted positive or the sepsis score was > or =14), nonseptic, and controls. Based on blood culture results, the septic group was subdivided into bacteremic and nonbacteremic foals.

RESULTS

Blood culture was performed in 62/74 septic foals, from which 35 (56%) were bacteremic and 27 (44%) were non-bacteremic. Anterior uveitis was diagnosed in a significantly (P < .005) higher number of septic/bacteremic foals (14/35, 40%) than in septic/nonbacteremic foals (5/27, 19%), nonseptic foals (4/54, 7%), and control foals (0%). Anterior chamber fibrin was only observed in 4/14 (29%) septic/bacteremic foals with anterior uveitis. Anterior uveitis was also associated with posterior uveitis in 6/35 (19%) septic/bacteremic foals. The diagnosis of uveitis was related to nonsurvival (P = .001, odds ratio = 6.2, 95% confidence interval = 2.1-18.2).

CONCLUSIONS AND CLINICAL IMPORTANCE

Anterior uveitis is highly prevalent in septic newborn foals, especially in those with a positive blood culture, and it should be considered as a survival prognostic factor.

Arterial lactate concentration, hospital survival, sepsis and SIRS in critically ill neonatal foals

REASONS FOR PERFORMING STUDY

Blood lactate concentration has been shown to be a useful clinical indicator in human patients, but has not been formally investigated in critically ill foals.

OBJECTIVE

To investigate the association of blood lactate with hospital survival, markers of cardiovascular status, metabolic acid base status, sepsis and systemic inflammatory response syndrome (SIRS).

METHODS

A database containing clinical, haematological, plasma biochemical and hospital outcome data on neonatal foals referred to an intensive care unit in 2000-2001 was analysed. Seventy-two foals for which arterial lactate was measured at admission were included in the study.

RESULTS

Sixty-one foals had an admission lactate concentration > 2.5 mmol/l. Admission lactate was statistically associated with hospital survival, mean arterial pressure, blood creatinine concentration, bacteraemia, anion gap, lactate concentration at 18-36 h after admission and evidence of SIRS, but not with packed cell volume or heart rate. Lactate at 18-36 h was also associated with survival and evidence of SIRS. Anion gap, base excess, base excess due to unidentified anions (BEua), simplified strong ion gap or bicarbonate correctly classified foals for presence of hyperlactaemia (> 5 mmol/l) in < or = 80% of animals.

CONCLUSIONS

Admission blood lactate gives important prognostic information. Lactate should be measured rather than assumed from the anion gap, base excess, BEua, simplified strong ion gap or bicarbonate.

POTENTIAL RELEVANCE

Blood lactate concentrations at admission are clinically relevant in neonatal foals and warrant further investigation. This should include the clinical value of measuring changes in lactate in response to treatment.

Relationships between early foal health, future performance and their dams reproductive health

The objectives of this study were to investigate: (i) relationships between early foal health and their dams' reproductive health at mating/conception as well as after parturition and (ii) health status during early foal life and its association with performance as an adult. The study included 35 foals showing clinical symptoms indicating septicaemia, sometimes in combination with other disturbances, within their first 18 h postpartum (Group I). Eighty-eight foals that were healthy during their first few days of life were used as control (Group II). All foals were born in the same region of Sweden and during the same period, and were expected to become performance athletes based upon the pedigree of their parents. Cytological and bacteriological examination of uterus at the time of mating/insemination at which the foal was conceived, revealed no difference between dams of Group I and Group II foals. Within 2-3 days after parturition, 29% and 4% of dams (p < 0.001) of Group I and Group II foals had metritis, respectively. At 30 days post-parturition, 64% of the dams of Group I foals and 32% of the dams of Group II foals (p = 0.002) had cytological indication of endometritis, and 57% of the dams of Group I foals and 21% of the dams of Group II foals (p < 0.001) showed bacterial growth upon culture. Altogether 29% of the Group I foals and 7% of the Group II foals were killed or died before 2 years of age (p = 0.001). The majority of the remaining Group I foals were poor performers and some were used just for pleasure riding. It is hypothesized that (i) mares--delivering foals that compromised within their first 18 h postpartum--might have suffered from an ascending infection during late gestation and (ii) health status during early foal life might be associated with their performance as adult.

Expression of molecular markers in blood of neonatal foals with sepsis

OBJECTIVE

To determine gene expression of selected molecular markers (tumor necrosis factor [TNF]-alpha, interleukin [IL]-1beta, IL-6, IL-8, IL-10, procalcitonin [PCT], and transforming growth factor [TGF]-beta) in the blood of healthy and sick foals.

ANIMALS

28 sick foals without sepsis, 21 foals with sepsis, and 21 healthy foals.

PROCEDURES

Total RNA was extracted from blood samples and converted into complementary DNA (cDNA). Gene expression was measured for the molecular markers by use of real-time PCR assay, and final quantitation was performed with the comparative threshold cycle method.

RESULTS

Samples from all foals yielded transcription for all markers. Expression of TNF-alpha and TGF-beta was significantly lower and that of IL-8 significantly greater in the sick-nonseptic and septic groups, compared with the healthy group. No significant difference in expression of IL-1beta, IL-6, and PCT was found between the healthy group and the 2 sick groups. Expression of IL-10 was significantly greater in nonsurvivors, compared with survivors.

CONCLUSIONS AND CLINICAL RELEVANCE

The cytokine profile in foals with sepsis may suggest an immunosuppressive state. Expression of IL-10 may be a marker for identification of foals with a guarded prognosis.

Equine neonatal sepsis

Neonatal infection remains a leading cause of morbidity and mortality in the equine industry, despite advances in prevention and treatment. Many factors can influence a foal's risk for the development of sepsis in the peripartum period. This article discusses those factors, causative organisms, and therapeutic options. Factors that influence prognosis and potential preventative strategies also are addressed.

Risk Factors and Prognostic Variables for Survival of Foals with Radiographic Evidence of Pulmonary Disease

The medical records of 163 neonatal foals that had thoracic radiographs taken within 48 hours of admission to a referral hospital were reviewed. The objectives of this study were (1) to identify risk factors for the development of thoracic radiographic changes and (2) to identify prognostic indicators for survival in foals with radiographic evidence of pulmonary disease. Failure of transfer of passive immunity (IgG concentration < or = 400 mg/dL) was the only risk factor for radiographic evidence of respiratory disease identified by multivariate analysis. Hypoxemic patients (PaO2 < or = 60 mm Hg) were 4.9 times more likely to reveal radiographic abnormalities in a subset of foals for which arterial blood gas results were available. Foals with a serum creatinine concentration > 1.7 mg/dL upon presentation, dyspnea, and a history of dystocia were significantly more likely to die based on the multivariate statistical outcome analysis. An anion gap > or = 20 mEq/dL was strongly associated with nonsurvival in a subset of foals with arterial blood gas results. These hematologic and biochemical variables can be readily obtained during the initial evaluation of sick foals. The presence of a high anion gap appeared to have the greatest clinical impact and may be a useful prognostic indicator in foals with radiographic evidence of respiratory disease. In contrast, the majority of physical examination variables, including evaluation of tachypnea, abnormal respiratory sounds, fever, weakness, and milk reflux from the nares, which are usually obtained during the general respiratory evaluation of foals, were unrelated to outcome.

Clinical and Prognostic Significance of Radiographic Pattern, Distribution, and Severity of Thoracic Radiographic Changes in Neonatal Foals

A total of 207 thoracic radiographs obtained from 128 foals were evaluated to assess the impact of pulmonary radiographic pattern, distribution, and severity of pulmonary changes on short-term survival of neonatal foals. The association between selected clinical variables and the radiographic manifestation of neonatal respiratory disease was also investigated. The evaluation of interstitial and alveolar-interstitial radiographic patterns within the caudodorsal, caudoventral, and cranioventral lung regions proved to be highly reliable between viewers in the study. A diagnosis of systemic inflammatory response syndrome was related to increased pulmonary infiltrates within the caudodorsal lung region. Dyspneic foals had more extensive pulmonary infiltrates within the cranioventral lung, advanced respiratory disease, and lower survival rates. A fibrinogen concentration >400 mg/dL was associated with increased cranioventral radiographic abnormalities. In addition, tachypnea most consistently related to diffuse (caudodorsal, caudoventral, and cranioventral) pulmonary changes. Neutropenia, milk reflux from the nares, upper airway pathology, abnormal respiratory sounds, failure of transfer of passive immunity (IgG concentration <400 mg/dL), immaturity, or fever, however, were not related to radiographic pattern, distribution, or severity of radiographic changes. Sixty-five percent of foals with radiographic pulmonary disease were discharged alive from our referral hospital. Concurrent caudodorsal and caudoventral radiographic disease was most frequently observed in this foal population. Increased caudodorsal radiographic scores retained statistical significance as a prognostic indicator for nonsurvival in a multiple stepwise logistic regression analysis.

Intragastric pH in critically ill neonatal foals and the effect of ranitidine

OBJECTIVE

To characterize intragastric pH profiles in critically ill foals and determine whether administration of ranitidine altered pH profiles.

DESIGN

Prospective observational study.

ANIMALS

23 hospitalized neonatal foals < or = 4 days of age.

PROCEDURE

Intragastric pH was measured continuously for up to 24 hours by use of an indwelling electrode and continuous data recording system. In 21 foals, ranitidine was administered IV.

RESULTS

10 foals had predominantly or exclusively alkaline profiles, 10 had profiles typical of those reported for healthy foals, with periods of acidity (hourly mean pH < 5.0 at least once), and 3 had atypical profiles with periods of acidity. All 10 foals that had intragastric pH profiles typical of healthy foals survived, whereas only 2 foals with alkaline profiles survived, and none of the foals with atypical profiles survived. The effects of ranitidine administration could not be assessed in 13 foals because of a high baseline intragastric pH. In 7 of the remaining 9, ranitidine administration resulted in an alkalinizing response, but this response was often of blunted duration. Ranitidine administration did not appear to alter the intragastric pH profile in the remaining 2 foals.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that hospitalized critically ill foals often have intragastric pH profiles different from those reported for healthy foals and may respond differently to ranitidine administration than do healthy foals. Many critically ill foals have continuously alkaline intragastric pH profiles, questioning the need for prophylactic administration of ranitidine in all critically ill foals.

Uroperitoneum in the hospitalised equine neonate: retrospective study of 31 cases, 1988-1997

Historical, physical and diagnostic data were reviewed retrospectively in 31 equine neonates with uroperitoneum. Gender predilection was not observed, and classic electrolyte abnormalities were seen in less than 50% of the cases. Aetiologies for uroperitoneum have been well described, but this review found that septicaemia/severe illness played a crucial role the outcome of uroperitoneum. Approximately half the individuals with uroperitoneum had positive sepsis scores. Foals receiving fluid therapy were more likely to be septic and to have normal electrolyte concentrations. Ultrasonographic findings, serum creatinine and serum:peritoneal creatinine ratios were not affected by previous fluid therapy and were invaluable aids in the diagnosis of uroperitoneum, even with multisystemic disease such as sepsis.

Model to predict septicemia in diarrheic calves

The difficulty in distinguishing between septicemic and nonsepticemic diarrheic calves prompted a study of variables to predict septicemia in diarrheic calves, 28 days old that were presented to a referral institution. The prevalence of septicemia in the study population was 31%. Variables whose values were significantly different (P < .10) between septicemic and nonsepticemic diarrheic calves were selected using stepwise, forward, and backward logistic regression. Variables identified as potentially useful predictors were used in the final model‐building process. Two final models were selected: 1 based on all possible types of predictors (laboratory model) and 1 based only on demographic data and physical examination results (clinical model). In the laboratory model, 5 variables retained significance: serum creatinine > 5.66 mg/dL (> 500 μmol/L) (odds ratio [OR] = 8.63, P = .021), toxic changes in neutrophils ≥ 21 (OR = 2.88, P = .026), failure of passive transfer (OR = 2.72, P = .023), presence of focal infection (OR = 2.68, P = .024), and poor suckle reflex (OR = 4.10, P = .019). Four variables retained significance in the clinical model: age ≤ 5 days (OR = 2.58, P = .006), presence of focal infection (OR = 2.45, P = .006), recumbency (OR = 2.98, P = .011), and absence of a suckling reflex (OR = 3.03, P = .031). The Hosmer—Lemeshow goodness‐of‐fit chi‐square statistics for the laboratory and clinical models had P‐values of .72 and .37, respectively, indicating that the models fit the observed data reasonably well. The laboratory model outperformed the clinical model by a small margin at a predictabilty cutoff of 0.5, however, the predictive abilities of the 2 models were quite similar. The low sensitivities (39% and 40%) of both models at a predicted probability cutoff of 0.5 meant many septicemic calves were not being detected by the models. The specificity of both models at a predicted probability cutoff of 0.5 was .90%, indicating that .90% of nonsepticemic calves would be predicted to be nonsepticemic by the 2 models. The positive and negative predictive values of the models were 66–82%, which indicated the proportion of cases for which a predictive result would be correct in a population with a prevalence of septicemia of 31%.

Model to predict septicemia in diarrheic calves

The difficulty in distinguishing between septicemic and nonsepticemic diarrheic calves prompted a study of variables to predict septicemia in diarrheic calves <28 days old that were presented to a referral institution. The prevalence of septicemia in the study population was 31%. Variables whose values were significantly different (P < .10) between septicemic and nonsepticemic diarrheic calves were selected using stepwise, forward, and backward logistic regression. Variables identified as potentially useful predictors were used in the final model-building process. Two final models were selected: 1 based on all possible types of predictors (laboratory model) and 1 based only on demographic data and physical examination results (clinical model). In the laboratory model, 5 variables retained significance: serum creatinine > 5.66 mg/dL (>500 micromol/L) (odds ratio [OR] = 8.63, P = .021), toxic changes in neutrophils > or = 2+ (OR = 2.88, P = .026), failure of passive transfer (OR = 2.72, P = .023), presence of focal infection (OR = 2.68. P = .024), and poor suckle reflex (OR = 4.10, P = .019). Four variables retained significance in the clinical model: age < 5 days (OR = 2.58, P = .006), presence of focal infection (OR = 2.45, P = .006), recumbency (OR = 2.98, P = .011), and absence of a suckling reflex (OR = 3.03, P = .031). The Hosmer-Lemeshow goodness-of-fit chi-square statistics for the laboratory and clinical models had P-values of .72 and .37, respectively, indicating that the models fit the observed data reasonably well. The laboratory model outperformed the clinical model by a small margin at a predictabilty cutoff of 0.5, however, the predictive abilities of the 2 models were quite similar. The low sensitivities (39% and 40%) of both models at a predicted probability cutoff of 0.5 meant many septicemic calves were not being detected by the models. The specificity of both models at a predicted probability cutoff of 0.5 was >90%, indicating that >90% of nonsepticemic calves would be predicted to be nonsepticemic by the 2 models. The positive and negative predictive values of the models were 66-82%, which indicated the proportion of cases for which a predictive result would be correct in a population with a prevalence of septicemia of 31%.

Actinobacillus suis septicaemia in two foals

A 24-hour-old Hackney ony filly developed signs of weakness, depression and a poor suck reflex, with harsh lung sounds over both fields, and a 48-hour-old Arabian colt from a normal birth which had sucked vigorously developed loose stools and became depressed, weak and anorectic. Both foals had serum IgG concentrations greater than 800 mg/dl, but each had a severe neutropenia with a left shift, and blood cultures from both of them yielded Actinobacillus suis. The A suis isolates had different antimicrobial susceptibility patterns and, in the case of the Arabian, the isolate was resistant to commonly used broad spectrum antimicrobial agents.

Update on neonatal septicemia

Septicemia is the second most commonly diagnosed problem in the equine neonate, superseded only by the problem of inadequate transfer of maternal antibodies. This article reviews the factors that may put a foal at high risk for developing sepsis, the diagnostic tools used to identify these animals, some of the sequelae of sepsis, and the therapeutic modalities available to the clinician.

Clinical view of disturbances in equine foetal maturation

This review summarises comparative aspects of equine pregnancy and birth. The allantochorion covers the entire endometrial surface of the mare's uterus and the placenta is microcotyledonary and epitheliochorial in structure. The foetus has, therefore, to pass through the allantochorion at birth. The umbilical cord has amniotic and allantoic portions and remains intact after delivery, enabling an arterial venous circulation to be maintained for several minutes. Maternal IgG does not cross the placental barrier and passive transfer post-natally is essential for immune status. Gestation in Thoroughbreds is 340 days with a wide range (320-360 days). Birth may be induced by oxytocin but dose rate is related inversely to gestational age. Normal foals rise, suck from the mare and gallop within 4 h after birth. Categorisation of newborn foal diseases into infective (Group 1) and non-infective (Groups 2, 3 and 4) conditions is presented. The neonatal maladjustment syndrome (NMS) affects full-term individuals, causing cerebral oedema, haemorrhage and/or ischaemic necrosis. NMS is related to the birth process and myocardial 'injury'. Prematurity and dysmaturity have origins in pre-natal disturbances of foetal maturation and physiology. Prematurity is a term ascribed to foals delivered at less than 320 days gestation whereas dysmaturity, for clinical convenience, describes foals born in the full-term period showing premature-like signs. Dysmature foals are generally associated with placental pathology. However, the distinction between the two groups is tenuos. Recent evidence suggests that 1) placental pathology is often present in premature foals; 2) differences exist in the degree of adrenocortical function. These affect clinical signs, prognosis and course of the condition. Placental pathology results in precocious adrenocortical maturation but the effect on maturation of other organ systems requires further study. Premature/dysmature foals fall into two groups; those with a favourable clinical outcome and those which make progress during the first 24 h post partum but deteriorate with development of neurological, metabolic and respiratory deficits (second day syndrome). Two models have been established to study premature/ dysmature foals. The first, developed in the early 1980s, was based on induction of mares from 280 days gestation to full term, using oxytocin. A premature, intermediary (twilight) and full-term status of adrenocortical function were identified; these categories correlating with changes in mammary secretion electrolytes. The same groupings have been related to other organ systems and metabolic functions of maturation. The second model establishes placental pathology from 220 to 260 days of gestation. A small area of placenta is separated from its uterine attachment, using a videoendoscope introduced through the cervix. Precocious adrenocortical function has been induced although further work is required to confirm the model as a means of investigating the pathogenesis of dysmaturity. Foetal injections of ACTH, CRH or betamethasone cause precocious increases in maternal plasma pregnane concentrations.