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686 Neonatal Isoerythrolysis

Prognosis appears to be much better for dogs Technician Tips SUGGESTED READING
(>80% survival) than humans. Prognosis Close monitoring of vital signs and affected Naidoo SL, et al: Necrotizing fasciitis: a review. J Am
VetBooks.ir PEARLS & CONSIDERATIONS ing whether the infection is progressing and AUTHOR: Michelle Woodward, DVM, MS, DACVD
tissues and wounds can be helpful for identify-
appears to be worse for cats.
Anim Hosp Assoc 41:104-109, 2005.
further surgery is warranted. A Sharpie-type pen
EDITOR: Joseph Taboada, DVM, DACVIM
Comments can be used to mark skin along edge of affected
area to help monitor disease progression.
Early recognition and aggressive surgical and
medical management are important for a Client Education
favorable outcome. Referral to a 24-hour care Owners should be aware that treatment is
facility (in a timely manner) is ideal. frequently drastic, is costly, and should be
pursued quickly.

Neonatal Isoerythrolysis

BASIC INFORMATION • Urine that is dark red/brown (hemoglobinuria) Initial Database
• Tail tip necrosis (common in survivors) • Packed cell volume
Definition • Blood smear for cytologic evaluation of
Neonatal isoerythrolysis (NI) is a hemolytic Etiology and Pathophysiology RBCs: evidence of agglutination and/or
disease occurring in newborn kittens (and • Colostrum is the antibody-rich fluid found spherocytosis is consistent with NI
rarely in puppies). It is a type II hypersensitivity in the mammary gland at parturition. After • Pigmenturia in fading kittens strongly sug-
reaction in which antibodies from the mother’s about 48-72 hours, the mammary gland gests NI.
colostrum are directed against the red blood switches from colostrum to milk, which is
cells (RBCs) of the newborn. rich in immunoglobulins G (IgG) and A (IgA). Advanced or Confirmatory Testing
• The mammalian gut absorbs colostrum for • Blood typing of both parents (NI occurs
Epidemiology ≈24 hours after birth (highest in the first 16 when queen is type B, tom type A)
SPECIES, AGE, SEX hours). After gut closure occurs, antibody is • Cord blood can be used to type kittens if a
Far more common in neonatal cats than no longer absorbed into circulation but acts risky mating is known or suspected and the
dogs locally in the gut. tom is not available for typing.
• Cats with blood type B have naturally occur- • The diagnosis is confirmed by screening
GENETICS, BREED PREDISPOSITION ring anti-A antibodies without prior exposure maternal serum, plasma, or colostrum against
Feline breeds with a high prevalence of B (sometimes referred to as “isoantibodies”). the neonatal RBCs or paternal RBCs; in
blood type, such as British shorthair, Birman, If the queen is type B, these antibodies will essence a cross-match (p. 1084).
Devon rex, Scottish fold, Somali, Turkish be found in the colostrum.
van, Persian, or Abyssinian, are at higher risk • If the tom has type A blood (dominant to TREATMENT
for NI (p. 1203). type B), any type A offspring will ingest
maternal antibody (naturally occurring anti-A Treatment Overview
RISK FACTORS antibodies from the type B queen) when Treatment for NI is supportive; early identifica-
• Kittens with blood type A that are born to suckling colostrum. tion and intervention is key.
queens of blood type B • Colostrum-derived antibodies (especially
• Puppies born to dams that have previously IgG) targeting the kitten’s RBCs induces Acute General Treatment
received blood transfusions hemolysis similar to immune mediated- • Remove nursing animals from the queen until
hemolytic anemia (p. 60). blood types are established for all kittens in
GEOGRAPHY AND SEASONALITY • Cats with type A blood can develop anti-B the litter. Type B kittens can be returned to
Cats with type B blood are found more often antibodies. However, the anti-B reaction is a type B queen immediately.
in some locations (e.g., Australia, Greece, much less vigorous and the clinical signs • Remove blood type A kittens from queens
California) much less severe. for about 24 hours after birth.
• In dogs, maternal antibodies may develop to ○ Bottle-feed using a high-quality kitten
Clinical Presentation a specific foreign blood group from previous milk replacer until returned to queen.
HISTORY, CHIEF COMPLAINT transfusions but not from prior pregnancies. ○ Kittens deprived of colostrum are at
The kittens/puppies are typically normal at increased risk for infection.
birth and nurse vigorously. They begin to fade DIAGNOSIS ○ Adult serum (type A donor) can provide
48-72 hours after birth, exhibiting lethargy and antibody to colostrum-deprived kittens.
weakness. Diagnostic Overview • Anemic kittens may require transfusion
Blood type A kittens born to type B queens (p. 1169). If IV catheterization is impossible,
PHYSICAL EXAM FINDINGS are at high risk for NI. The diagnosis is usually the intraosseous route may be used.
• Weak, lethargic kitten(s) suspected based on history and clinical signs.
• Reduced vocalization PROGNOSIS & OUTCOME
• Hypothermia Differential Diagnosis
• Pale/white mucous membranes, sometimes Heritable RBC disorders, hemolytic toxins, The prognosis is guarded if NI is not recognized
icterus severe parasitism early.

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