Feline Neonatal Isoerythrolysis, FNI (Destruction of Red Blood Cells in Newborn Cats, Fading Kitten Syndrome) in cats
- Occurrence: rarer
- Location of illness: General/Whole body
Feline Neonatal Isoerythrolysis (FNI) is a life-threatening condition in newborn cats in which the kittens’ red blood cells are destroyed by the mother’s antibodies, leading to anemia and other serious health problems.
The most important facts at a glance
Feline Neonatal Isoerythrolysis (FNI) occurs when there is a blood type incompatibility between a mother cat with blood type B and her newborn kittens who have blood type A or AB. The mother transfers antibodies via the first milk, the colostrum, to the kittens, which leads to the destruction of their red blood cells. This can cause a rapidly developing anemia, which can be fatal without treatment. Symptoms of FNI include failure to thrive, weakness, loss of appetite, and respiratory distress. Diagnosis is made through clinical observations, blood tests, and determination of the blood types of the mother and kittens.
Treatment involves immediate separation of the kittens from the mother to stop the uptake of antibodies, as well as feeding with formula. In severe cases, a blood transfusion may be necessary. Supportive care, such as providing warmth and monitoring fluid intake, is crucial. The prognosis depends on the speed of treatment; with timely intervention, many kittens can be saved. To prevent FNI, breeders should know the blood types of the parent animals and avoid pairings that increase the risk. In an emergency, the kittens should be separated from the mother for the first 24 to 48 hours to avoid contact with dangerous antibodies.
Causes
Feline Neonatal Isoerythrolysis occurs when there is a blood type incompatibility between the mother cat and her newborn kittens. Cats have three main blood types: A, B, and AB. The most common blood type in cats is A, followed by B, while AB is very rare.
The incompatibility arises when a queen with blood type B, who has natural antibodies against blood type A, has kittens with a tomcat of blood type A. The kittens can then have blood type A or AB. The mother’s antibodies, which she passes on to her young through the first milk (colostrum), attack the red blood cells of the kittens who have blood type A or AB.
This antibody binding leads to hemolysis, meaning the kittens’ red blood cells are destroyed. This process leads to a rapidly developing anemia, which can be fatal without immediate treatment. Not all kittens in a litter are necessarily affected – it depends on their individual blood type.
Symptoms
The symptoms of FNI in kittens usually appear within the first hours to days after birth. A common sign is the so-called Fading Kitten Syndrome, in which the kittens appear weak and lethargic and do not drink effectively.
Other symptoms include pale or yellowish mucous membranes due to anemia and elevated bilirubin levels in the blood. Occasionally, jaundice can also be observed. In extreme cases, the kittens may suffer from respiratory distress or develop convulsions.
Another specific symptom is discoloration of the skin on the ears, tail, or paws due to the destruction of red blood cells. Occasionally, a brown discoloration of the urine is also observed, indicating hemoglobinuria, another sign of red blood cell breakdown.
Diagnosis
The diagnosis of FNI is made through a combination of clinical symptoms and specific tests. A blood test can show signs of anemia, and blood typing in the kittens and the mother can provide clues to an incompatibility.
A direct Coombs test can also be performed to detect the presence of antibodies on the kittens’ red blood cells. In some cases, an examination of the colostrum for antibodies is also performed.
The veterinarian will also take a detailed history to determine the parents’ blood types and to understand whether there may be a genetic predisposition to the disease.
Therapy
Treatment for FNI requires rapid and targeted measures. The first step is to prevent further antibody uptake through colostrum by separating the kittens from the mother and feeding them with formula.
In severe cases, a blood transfusion may be necessary to replace the red blood cells. The blood transfusion should come from a donor with a compatible blood type to avoid further immunological reactions.
Supportive care is also crucial to keep the kittens stable. This includes providing warmth and monitoring fluid intake to prevent dehydration. As the kittens are susceptible to infections, prophylactic antibiotics may also be administered.
Prognosis and follow-up care
The prognosis for kittens with FNI depends heavily on the severity of the disease and the speed of treatment. With timely diagnosis and intervention, many kittens can be saved, although some may develop long-term health problems.
In cases where severe anemia or organ damage occurs, the prognosis may be worse. Some kittens who are severely affected may not survive despite treatment.
However, if early action is taken to prevent antibody uptake and provide the necessary supportive treatments, many kittens can achieve a normal quality of life.
Prevention
To prevent Feline Neonatal Isoerythrolysis (FNI), it is important to know the blood types of breeding cats. Cats have three main blood types: A, B, and AB. The risk for FNI exists mainly when a blood type B cat is mated with a blood type A cat, as the offspring can have blood type A. These newborn kittens can then absorb antibodies through the mother’s milk, which destroy their red blood cells.
To avoid this, breeders should have the blood types of the parent animals determined before breeding. If a mating between a blood type B cat and a blood type A cat is unavoidable, alternative measures can be taken. One option is to separate the newborn kittens from the mother for the first 24 to 48 hours and feed them with special formula instead to prevent contact with the dangerous antibodies.
In addition, it is advisable to use cats with blood type AB or the same blood types in breeding to minimize the risk of FNI. Careful planning and monitoring of breeding processes can help to avoid this disease and ensure the health of the kittens.