What is Immune-Mediated Polyarthritis?

     

Never heard of this before?  We hadn't either until Velcro was recently diagnosed with it.  We had to do some research to see exactly what this is and how he might have developed it.

 

Immune-Mediated Polyarthritis (IMPA), more commonly found in dogs rather than cats, is kind of like arthritis in overdrive and is most closely related to rheumatoid arthritis in people.  With IMPA, a cat's immune system causes inflammation in the joints leading to swelling and pain.  These symptoms make it hard for cats to walk and significantly decrease their quality of life.  

 

With this condition present, a cat's immune system is mistakenly signaled that there's an infection in the joints and starts sending white blood cells to fight it.  The white blood cells get to the joints and start releasing chemicals and enzymes into the fluid that lubricates the joints, causing it to break down leading to pain and stiffness.  Because with IMPA the body turns on itself,  it's considered an auto-immune condition.

The signs that a cat may be experiencing IMPA include soreness, unwillingness to move, swollen joints and crying out if touched where pain is located. Some cats may also run a fever and develop anorexia.  Because we monitor all the BCR cats closely, we noticed right away that Velcro was stiff, limping and was clearly in pain, so we got him to the veterinarian right away.

There are quite a few diagnostic tools a veterinarian may use to determine whether or not a dog or cat has IMPA or if there's something else causing the joint pain.  Blood tests, urinalysis and imaging to see the severity of any swelling and to rule out other possible conditions like cancer or a specific infection are among these options.  To further determine if the cause is IMPA, a vet will likely extract some fluid from the joint or joints to see if any other kind of infection is present.  Because Velcro is both FIV- and leukemia-positive, his immune system is doubly weakened, which is likely the cause of his IMPA.
 

While waiting for his specific diagnosis, Velcro began taking several medications to address his pain and inflammation as well as to treat any possible infections.  These included antivirals, antibiotics, steroids, and immune support supplements.  All of these are among  frequently used IMPA treatments.  Once it was determined that IMPA was, in fact, the cause of Velcro's pain and swelling, he continued on steroids.  Since then, his condition has greatly improved and at the time of writing this blog, he will be rechecked in a month.

 

IMPA-positive cats like Velcro can live long happy lives with consistent care from cat parents and regular monitoring by a veterinarian.  Over time, the condition may change, medication dosages may need to be adjusted, and new therapies may be developed to treat joint problems.  A veterinarian or specialist will need to see an IMPA cat regularly to be sure the cat is receiving the most effective treatment.  We will be doing that with Velcro to ensure his quality of life and happiness.

 

 

CLICK HERE for a clinical overview of IMPA from the Merck Veterinary Manual.

CLICK HERE to read an IMPA article by the Veterinary Specialty Center.