What are Immune-Mediated Poly-Arthritis?

This type of arthritis is similar to rheumatoid arthritis that impacts humans as well. There is often times no cause or reason behind the arthritis and the symptoms can come and go without explanation. There is no cure for arthritis, however, there are ways to help your dog live his best and most comfortable life.

This disorder is the most common type of arthritis for dogs and can cause pain, difficulty walking, muscle atrophy, and more in your dog. This condition can cause symptoms that mimic other disorders as well and there is no guarantee that your dog will exhibit textbook symptoms. Immune-mediated poly-arthritis can impact both small and large breed dogs equally.

Immune-mediated poly-arthritis (IMPA) is a noninfectious disorder of your dog’s immune system that impacts his joints. It is possible to cause inflammation in all joints which can cause your dog to be in discomfort and pain.

Immune-Mediated Poly-Arthritis Average Cost

From 593 quotes ranging from $800 - $4,000

Average Cost

$2,500

Symptoms of Immune-Mediated Poly-Arthritis in Dogs

The symptoms of IMPA can vary and look like other disorders, as the signs are often generic to multiple disorders. The symptoms listed may not all be present and may come and go over time.  

  • Lameness
  • Multiple joint pain
  • Joint swelling
  • Fever
  • Malaise
  • Anorexia
  • Lethargy
  • Difficult walking/standing
  • Stiffness
  • Vomiting
  • Diarrhea
  • Lymph nodes enlarged

Types

There are 2 larger subtypes – erosive and nonerosive IMPA and within that there are 4 subtypes of IMPA – Type I, Type II, Type III and Type IV. Erosive IMPA indicates there has been some damage to bone and/or cartilage. Nonerosive indicates there has not been any damage to bone or cartilage in your dog. 

Type I – Non identifiable disease

  • Most common of all IMPA
  • Accounts for more than 50% of all cases of IMPA in dogs
  • Diagnosis of exclusion

Type II – Infectious or inflammatory disease related

  • Superficial pyoderma
  • Urinary tract infection
  • Pneumonia
  • Endocarditis
  • Mastitis
  • Dirofilariasis
  • Fungal infection
  • Pleuritis
  • Severe periodontal disease
  • Diskospondylitis
  • Chronic salmonellosis
  • Bacterial prostatitis
  • Bacterial tonsillitis
  • Pharyngitis
  • Dermatitis
  • Pancreatitis

Type III – Seen with chronic stomach disease

  • Inflammatory bowel disease
  • Intestinal malabsorption
  • Bacterial overgrowth
  • Ulcerative colitis
  • Chronic and bacterial diarrhea
  • Eosinophilic gastric
  • Lymphocytic-plasmacytic hepatitis

Type IV – Associated with abnormal cells

  • Squamous cell carcinoma
  • Mammary adenocarcinoma
  • Leiomyoma
  • Heart base tumor
  • Seminoma

Other types

  • Breed associated
  • Drug associated
  • Vaccine associated
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Causes of Immune-Mediated Poly-Arthritis in Dogs

In the subtypes I-IV, 3 of them have known causes and those cases make up about 50% of dogs diagnosed with IMPA. However, Type I does not have any specific known causes and accounts for 50% of cases. 

Type I 

  • Typically, no known cause
  • Common in all ages and breeds

Type II

  • Reactive to an infection
  • Bacterial infection
  • Fungal infection
  • Viral infection

Type III

  • Stomach/intestinal related
  • Liver related
  • Rare in dogs

Type IV

  • Overgrowth of cells outside of your dog’s joints
  • Rarest form of IMPA 

Other Causes 

  • Breed associated (Akita, Chinese Shar-Pei, Boxer, Weimaraner, Bernese Mountain,German Shorthaired Pointer, Spaniel and Beagle breeds)
  • Drug associated (given within 30 days of onset of symptoms, but typically occurs within 5-20 days after drug administered - sulfonamides, lincomycin, erythromycin, cephalosporins, phenobarbital, penicillins)
  • Vaccine associated (administered within 30 days of onset of symptoms, somewhat weak link between the 2)
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Diagnosis of Immune-Mediated Poly-Arthritis in Dogs

If you begin to notice that your dog is suffering from pain, discomfort, difficulty walking and other odd symptoms with no readily available explanation, your veterinarian may be able to help you. Your veterinarian will most likely want to do a full physical exam on your dog to see if he is having pain, swelling in his joints, unexplained fever and other common symptoms to begin diagnosing.

Once your veterinarian performs a physical exam she will most likely want to hear about your dog’s history of other health concerns including any medication changes or recent vaccinations, injuries, exposure to anything that could have resulted in his symptoms. While a physical exam and history alone can diagnosis IMPA, your veterinarian may want to run some tests as well.

These tests could include drawing fluid from your dog’s joints (arthrocentesis), and x-rays of joints he is feeling pain in to see any deterioration of those areas. Your doctor may want to rule out lyme disease, other tick borne disease, and any other possible underlying causes via blood tests. Tests may be done on your dog’s stomach to determine if the cause is Type III as well – including ultrasounds, x-rays or scans. 

When prepping for your visit with your veterinarian it is important to gather as much information as possible to share with her about your dog. It would be beneficial to have a timeline of how long your dog has been suffering from symptoms and what his exact symptoms are. It would also help your veterinarian to make the best diagnosis for your dog if you can give any specifics as to when it gets worse or better, or if you have noticed the symptoms come and go over time, as arthritis symptoms tend to do this.

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Treatment of Immune-Mediated Poly-Arthritis in Dogs

In terms of treatment options for your dog, your veterinarian will most likely suggest medication management for your dog’s symptoms as the disease is not curable. Learning to manage your dog’s symptoms will lead to a happier, healthier and pain-free life for him. 

Medication management for your dog’s symptoms is the go to option for many veterinarians. These medications fall under two categories which are immunosuppressive  and chemotherapeutic medications. Immunosuppression medications will be anti-inflammatory typically, such as corticosteroids (prednisone) alongside other medications (chemotherapeutic) such as Azathioprine, Leflunomide, and Cyclophosphamide. Long term corticosteroid use can have side effects also such as diabetes, urinary tract infections and hyperadrenocorticism. 

It is recommended that liver enzymes be checked out if your dog is on Azathioprine, and side effects can include bone marrow becoming suppressed and cystitis. Azathioprine can be used for a longer period of time than Cyclophosphamide which is not recommended past four months of use. 

Immunomodulation drugs which are used to regulate your dog’s immune system have been found to be beneficial if your dog’s IMPA does not go in remission or they have a relapse of symptoms. There are some side effects however, such as lethargy, vomiting, diarrhea, agitation, and anemia. 

Medication management is done over the course of 2-4 months and if your dog is responding, your veterinarian will begin to taper him down off of the medications. The taper can take another 2-4 months after that. 

There is a high rate of relapse with IMPA due to the fact that it can act up anytime and without warning. The prognosis is good for Type I with ongoing medication management. Types II-IV have a good prognosis assuming the underlying cause of their IMPA is treated adequately in order to take care of the IMPA symptoms. Up to 56% of dogs have gotten off of medication management therapy.

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Recovery of Immune-Mediated Poly-Arthritis in Dogs

It will be important as your dog continues to age and grow to have him checked out regularly for any changes in his IMPA symptoms and any necessary medication changes. Your dog may relapse as discussed above, so follow up appointments will be beneficial to keep him comfortable. 

If it has been found that your dog’s IMPA was the cause of Type II-IV you may have to continue working with his veterinarian to ensure those underlying issues are continuing to be taken care of as well. Keeping up with your dog’s medication and making sure he is taking them as directed will also help him to remain pain-free.

Lastly, as there is no cure for IMPA you can expect to deal with possible flare ups throughout your dog’s life. However, once the underlying issues are handles in Types II-IV it should be easier to control the IMPA and your dog should be able to continue his normal routine.

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Immune-Mediated Poly-Arthritis Average Cost

From 593 quotes ranging from $800 - $4,000

Average Cost

$2,500

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Immune-Mediated Poly-Arthritis Questions and Advice from Veterinary Professionals

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Elton

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Hound

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4 Years

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Moderate severity

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0 found helpful

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Moderate severity

Has Symptoms

Limb Swelling
Limping

My dog Elton was diagnosed with IMPA and prescribed presnidone 15 mg x 2 per day. He initially responded well and in 3 days was back to his normal self but a few days after he started to regress and became lethargic and unable to walk/stand on his own. We took him back to the hosptial where they re-examined him and didn’t feel the need to run additional tests, felt this came on from overuse and prescribed strict crate rest a long with the same presnidone dosages. Elton had to be a carried for a few days to his walks but today was finally able to walk (short just to pee) on his own. However, he did have throat swelling in the beginning (which caused them to do an endoscopy before diagnosing the IMPA through a joint tap) and we came to decide with the vet that the swelling was a result of the inflammation and pain (it has gone down significantly since) but Elton has still lost his bark. The engiscopy showed no foreign objects or abnormalities of the throat. Could this still be a side effect of the inflammation? We have only had him on presnidone for a week thus far.

Aug. 12, 2018

Elton's Owner

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0 Recommendations

Some inflammation may occur after endoscopy, but shouldn’t be too severe and the corticosteroids should also help with that; keep an eye on Elton for the time being and ensure that he he is kept well rested. If there is no improvement over the next few days return to your Veterinarian. Regards Dr Callum Turner DVM

Aug. 12, 2018

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Gibson

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Catahoula Bulldog

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7 Years

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Serious severity

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0 found helpful

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Serious severity

Has Symptoms

See Above

Hello, My 7yr old, 55lb bully mix was diagnosed with IMPA last November. He has been treated with prednisone, but is experience very extreme side affects that are now potentially life threatening. Mychophenolate was added before tampering the pred. He relapsed on 3 occasions even at previously therapeutic levels. Cyclosprine was added to the mix and after 3-4 days, a very fast tamper of pred (reduction every 3-4 days) resulted in another relapse. We are now experiencing significant protein in the urine (5.7!), in addition to the pancreatitis, increased liver enzymes (controlled with Denamarin), and extreme muscle wasting caused by the prednisone. We are evaluating Leflunimide currently, but have started Benazapril in the short term. Any advise is appreciated as my vet is struggling with next steps. He is currently on all medications listed above except Cyclosporine, which was deemed ineffective.

April 18, 2018

Gibson's Owner


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Dr. Michele K. DVM

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0 Recommendations

I'm sorry that this is happening to Gibson. Given your description, it might be best to have a referral to a specialist by your veterinarian. It seems that they have done a great job managing his disease, but his condition is complicated, and a specialist is often helpful to provide ongoing support and care.

April 18, 2018

Our lab was DX with IMPA 2 months ago. Takes high dose Prednisone and Cyclosporin. She is very weak, no energy at all. Taking Codeine for pain. She just turned 2 years. We tried Holistic meds, prescribed by her general vet, not the internist, Phytoprofen, Yi Yi Ren Tang, and she vomited. We stopped and started same meds, she vomited so off the Holistic meds. Were trying BPC-157 injections. Hope this helps, but nothing much helping at month 2. We are treating joints with cold laser TX.

June 24, 2018

Patty H.

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Immune-Mediated Poly-Arthritis Average Cost

From 593 quotes ranging from $800 - $4,000

Average Cost

$2,500

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