Convulsive and allied syndromes of the neonatal foal

Equine Neonatal Encephalopathy: Facts, Evidence, and Opinions

Neonatal encephalopathy (NE) and neonatal maladjustment syndrome (NMS) are terms used for newborn foals that develop noninfectious neurologic signs in the immediate postpartum period. Cerebral ischemia, hypoxia, and inflammation leading to neuronal and glial dysfunction and excitotoxicity are considered key mechanisms behind NE/NMS. Attention has been placed on endocrine and paracrine factors that alter brain cell function. Abnormal steroid concentrations (progestogens, neurosteroids) have been measured in critically ill and NE foals. In addition to supportive treatment, antimicrobials should be considered. Controversies regarding the pathophysiology, diagnosis, and treatment of NE and NMS will remain until controlled mechanistic and therapeutic studies are conducted.

Use of a multivariable model to estimate the probability of discharge in hospitalized foals that are 7 days of age or less

OBJECTIVE

To create a mathematical model to assist in early prediction of the probability of discharge in hospitalized foals < or= 7 days old.

STUDY DESIGN

Prospective study.

ANIMALS

1,073 foals.

PROCEDURES

Medical records from 910 hospitalized foals < or = 7 days old for which outcome was recorded as died or discharged alive were reviewed. Thirty-four variables including historical information, physical examination findings, and laboratory results were examined for association with survival. Variables associated with being discharged alive were entered into a multivariable logistic regression model. Accuracy of the model was validated prospectively on data from 163 foals.

RESULTS

Factors in the final model included age group, ability to stand, presence of a suckle reflex, WBC count, serum creatinine concentration, and anion gap. Sensitivity and specificity of the model to predict live discharge were 92% and 74%, respectively, in the retrospective population and 90% and 46%, respectively, in the prospective population. Accuracy of an equine clinician's initial prediction of the foal being discharged alive was 83%, and accuracy of the model's prediction was 81%. Combining the clinician's prediction of probability of live discharge with that of the model significantly increased (median increase, 12%) the accuracy of the prediction for foals that were discharged and nonsignificantly decreased (median decrease, 9%) the accuracy of the predication for nonsurvivors.

CONCLUSIONS AND CLINICAL RELEVANCE

Combining the clinician's initial predication of the probability of a foal being discharged alive with that of the model appeared to provide a more precise early estimate of the probability of live discharge for hospitalized foals.

Survey of retinal haemorrhages in neonatal thoroughbred foals

Twenty-seven of 167 neonatal thoroughbred foals (16 per cent) were found to have retinal haemorrhages after a careful examination of the entire fundus. Experience in differentiating haemorrhages from other lesions, and the selection of foals from normal populations, were considered to have an important effect on their apparent incidence. Bilateral haemorrhages were more common and there was a significantly higher incidence in female foals. The numbers of haemorrhages ranged between one and 20; 36 per cent of eyes with retinal haemorrhages had the small punctate type and 56 per cent had the splash-like form. There was no change from one type of haemorrhage to another, and the patterns of resolution were similar. The haemorrhages were in the tapetal fundus, except two that were recorded in the optic disc, and they resolved within 10 days. No short- or long-term ocular or neurological effects of the retinal haemorrhages were detected, and they were not related to the incidence of abnormal foal behaviour.

Subconjunctival haemorrhages in neonatal thoroughbred foals

A survey of 169 neonatal thoroughbred foals revealed that 8.3 per cent had subconjunctival haemorrhages, but there was no indication of a relationship between retinal and subconjunctival haemorrhages. The haemorrhages were not related to any abnormality of the foals and there was no sex or eye predisposition. In most cases the haemorrhages were fresh and red, occurred mainly dorsally or dorsonasally and extended up to the limbus; they resolved completely within four to 10 days, depending on their initial severity and extent. They had no effect on the foals' vision in the short or long term. The incidence of subconjunctival haemorrhages was associated with foaling category, multiparity and country of birth.