Factors Associated with Outcome in Foals with Neonatal Isoerythrolysis (72 Cases, 1988–2003)

Abstract

Background: Neonatal foals with isoerythrolysis (NI) often die, but the risk factors for death have not been identified. Objectives: To identify factors associated with outcome in foals with NI and to identify factors associated with death from liver failure or kernicterus in the same population.Animals: Seventy-two foals with NI examined at referral institutions. Methods: Retrospective case series. Information on signalment, clinical examination findings, laboratory testing, treatment, complications, outcome, and necropsy results were obtained.Results: The overall survival rate was 75% (54 of 72). Liver failure (n 5 7), kernicterus (n 5 6), and complications related to bacterial sepsis (n 5 3) were the 3 most common reasons for death or euthanasia. The number of transfusions with blood products was the factor most strongly associated with nonsurvival in a multivariate logistic regression model. The odds of liver failure developing in foals receiving a total volume of blood products ! 4.0 L were 19.5 (95% confidence intervals [CI]: 2.13-178) times higher than that of foals receiving a lower volume (P 5 .009). The odds of kernicterus developing in foals with a total bilirubin ! 27.0 mg/dL were 17.0 (95% CI: 1.77-165) times higher than that of foals with a lower total bilirubin (P 5 .014).Conclusions and Clinical Importance: Development of liver failure, kernicterus, and complications related to bacterial sepsis are the most common causes of death in foals with NI. Foals administered a large volume of blood products are at greater risk for developing liver failure.

Selected Arterial Blood Gasometry Parameters as Indicators of Blood Transfusion Effectiveness in Foals with Haemolytic Disease

“…The pathogenesis of the disease involves the breakdown of the newborn's erythrocytes by antibodies present in the colostrum of sensitised mothers, which decreases RBC counts, haematocrit and haemoglobin levels in the blood. Similar results were reported by Polkies et al (11) in a study of isoerythrolysis in foals. A decrease in RBC counts and haemoglobin levels lowers the amount of oxygen supplied to body tissues.…”

“…According to Whiting and David (16), and Polkes et al (11), haematocrit values lower than 0.2 l/l and poor health pose a threat to the foal's life, and constitute indications for blood transfusion. In this study, foals received whole blood in the amount and at the rates recommended for horses by Orsini and Divers (9).…”

“…It results from the uptake of colostrum containing antibodies directed against the newborn's red blood cells (RBC). Haemolytic disease relatively frequently leads to death (11). The serological conflict occurs when a foal inherits RBC antigens, which the mare does not have.…”

The Effects of Deferoxamine Mesylate on Iron Elimination after Blood Transfusion in Neonatal Foals

“…There is a strong association between the volume of blood administered and the likelihood of development of liver failure in foals with NI. Foals treated with ≥4 L of blood or blood products were 19.5 times more likely to develop hepatic failure than those treated with a lower volume 1 . Hepatic histologic lesions of foals with NI that develop liver failure 1 are identical to those after oral administration of ferrous fumarate to newborn foals 2–5 .…”

“…Most foals diagnosed with NI require one or more blood transfusions. There is an approximately 25% case fatality rate for foals treated for NI, with the most common causes of death being hepatic failure, kernicterus, and complications resulting from sepsis 1 . There is a strong association between the volume of blood administered and the likelihood of development of liver failure in foals with NI.…”