Neonatal Isoerythrolysis Neonatal Isoerythrolysis Pathogenesis - - PowerPoint PPT Presentation

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Neonatal Isoerythrolysis Neonatal Isoerythrolysis Pathogenesis - - PowerPoint PPT Presentation

Sep 06, 2023 220 likes •454 views

Neonatal Isoerythrolysis Neonatal Isoerythrolysis Pathogenesis Immune mediated hemolytic anemia Mediated by maternal anti-RBC antibodies Colostrum Neonatal Isoerythrolysis Pathogenesis Foal inherits specific RBC Ag from the sire

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SLIDE 1

Neonatal Isoerythrolysis

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SLIDE 2

Neonatal Isoerythrolysis Pathogenesis

  • Immune mediated hemolytic anemia
  • Mediated by maternal anti-RBC antibodies
  • Colostrum
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SLIDE 3

Neonatal Isoerythrolysis Pathogenesis

  • Foal inherits specific RBC Ag from the sire
  • Dam does not have these Ag
  • Dam previously sensitized
  • Placental bleeding - previous pregnancies
  • Previous whole blood transfusion
  • Equine biologics
  • Plasma contaminated with RBC Ag
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SLIDE 4

Neonatal Isoerythrolysis Pathogenesis

  • Current pregnancy mare re-exposed
  • Mounts antibody response
  • Concentrates antibodies in colostrum
  • Foal absorb the colostral Abs
  • Hemolytic Anemia
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SLIDE 5

Neonatal Isoerythrolysis Pathogenesis

  • 32 blood group antigens in horses
  • Aa and Qa 90% of the reactions
  • R and S groups most of the rest
  • Based on gene frequencies
  • TB, QH, Saddlebred, - Qa & Aa
  • Standardbred, Morgan - Aa (not Qa)
  • Arabian - Qa
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SLIDE 6

Neonatal Isoerythrolysis Clinical signs

  • Onset
  • 8-120 hours old
  • Depends on amount of antibody absorbed
  • Titer in colostrum
  • Amount ingested
  • More antibody absorbed
  • More rapid the onset
  • More severe the disease
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SLIDE 7

Neonatal Isoerythrolysis Peracute disease

  • Severe, acute anemia (massive hemolysis)
  • No hypoxemia
  • Tissue hypoxia
  • Metabolic acidosis
  • MODS
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SLIDE 8

Neonatal Isoerythrolysis Peracute disease

  • Normal at birth
  • Sudden onset
  • Weakness
  • Tachycardia
  • Tachypnea
  • Collapse
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SLIDE 9

Neonatal Isoerythrolysis Peracute disease

  • Neurologic derangement
  • Fever or hypothermia
  • Cardiovascular collapse
  • Shock
  • Death - often before icteric
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SLIDE 10

Neonatal Isoerythrolysis Acute disease

  • Normal at birth
  • Progressive weakness
  • Icterus (may become extreme)
  • Exercise intolerance
  • Tachycardia
  • Tachypnea
  • Fever (secondary to hemolysis)
  • Hemoglobinuria
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SLIDE 11

Neonatal Isoerythrolysis Subacute disease

  • Normal at birth
  • Only sign may be icterus
  • Can be febrile
  • Can have brief hemoglobinuria
  • Mild tachycardia/tachypnea
  • May go undetected
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SLIDE 12

Neonatal Isoerythrolysis Lab data

  • Anemia - mild to severe (as low as 4-8%)
  • Plasma very icteric
  • Plasma may be pink
  • Hyperbilirubinemia - primarily unconjugated
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SLIDE 13

Neonatal Isoerythrolysis Test before foal nurses

  • Hemolytic test
  • Dam's serum
  • + foal's RBC
  • + complement
  • Not easily done on farm
  • Jaundice Foal Agglutination Test
  • Does not test hemolysis
  • But good correlation with it
  • Easy procedure
  • Whole blood cross match
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SLIDE 14

Neonatal Isoerythrolysis Treatment

  • If signs during first 24 hours
  • for first 24-36 hrs
  • Strip colostrum from mare
  • Discard - do not feed to other foals
  • Don’t allow nursing
  • Separate foal from mare
  • Muzzle foal and cover udder
  • Find foal alternate source of colostrum
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SLIDE 15

Neonatal Isoerythrolysis Treatment

  • Most important - minimize stress
  • Difficult since otherwise normal
  • Need to be confined - blood samples
  • Monitor PCV (serial samples needed)
  • Watch for hemolytic episodes
  • Fever
  • Hemoglobinuria
  • Tachypnea, Tachycardia
  • Muscle fasciculations
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SLIDE 16

Neonatal Isoerythrolysis Treatment

  • Particularly susceptible to infections
  • Insure adequate IgG
  • Antimicrobial therapy in severe cases
  • Maintain adequate nutrition, hydration
  • Monitor renal function
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SLIDE 17

Neonatal Isoerythrolysis Blood transfusion

  • PCV in low teens
  • PCV is dropping rapidly
  • When signs of severe anemia are present
  • Even if PCV is not extremely low
  • Monitor lactate
  • Monitor HR
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SLIDE 18

Neonatal Isoerythrolysis Blood transfusion

  • Whole or packed cells
  • Mare's washed RBC
  • Aa and Qa Ag negative donor
  • Cross-matched blood
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SLIDE 19

Neonatal Isoerythrolysis Blood transfusion

  • Cross-match
  • Major side compatibility
  • Minor will not be compatible
  • Foal's RBC's already coated with Ab
  • Autoagglutinate or autohemolize
  • Transfused RBC (if well matched)
  • Nearly normal life span
  • Unlike older horses
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SLIDE 20

Neonatal Isoerythrolysis Prevention - Identify mares at risk

  • If mare has had an NI foal
  • Can blood type mare and stallion
  • Breed based on blood groups
  • Predict likelihood of problem
  • Test mare's sera
  • In late pregnancy
  • Run the JFA test before foal nurses
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SLIDE 21

Neonatal Isoerythrolysis Prevention - Take measures at birth

  • Cover udder in late pregnancy
  • Attend birth
  • Before foal nurses & for first 24-36 hr
  • Separate foal/mare
  • Muzzle foal and cover udder
  • Strip colostrum from mare
  • Alternate source colostrum/nutrition
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SLIDE 22

Neonatal Isoerythrolysis Sequela

  • Kernicterus
  • Iron Toxicity
  • Liver failure