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Author Topic: IMPA without fever or swelling?  (Read 34 times)


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IMPA without fever or swelling?
« on: September 09, 2018, 10:15:45 PM »

My mixed breed dog, Howdy, started limping in June on her left leg on and off. During and unrelated grass awn extraction from her ear the vet took x-rays of her back and knees and everything looked normal. A couple weeks later it swapped to her right leg, and a different vet prescribed Rimadyl and rest for a few weeks.

By late July she was having extreme trouble getting up after resting (I had to help her up with a towel a few times). Another vet trip led to lots of x-rays of the whole spine from different angles that came back normal.

Bloodwork/Urine results had a few abnomalities:
High globulin (4.1), high alkaline phosphate (192), RBC in urine, Alkiline urine, Protein in urine 1+.

Again only recommendations to keep her down and give her Rimadyl—which somewhat helped the pain, but not the stiffness.

Protein electrophoresis a couple weeks later showed the globulin had raised to 5.0, and an immunosuppressive dosing schedule of prednisone was suggested. I've postponed putting her on it because she rallyed for a couple weeks, acting much better. But more extreme limping over the last couple days has made me think it might be time to try. My main questions is about symptoms.

In summary she:
- Has shifting limp on back two legs—no fever, no noticable swelling (sometimes shows pain in a front paw, but not as extreme)
- Licks her joints more than usual (especially her front feet)
- still has her appetite, is playful execept when she's having her worst stiff/painful days.
- seems to feel the worst after resting (hard to get up), and after having
- had a surge of keratosis on her feet, which has since resolved.
- has starting to lose hair on her ear tips.

Has anyone experienced a dog having IMPA without any fever + swelling?
Is it common to do a prednisone trial on dogs that don't have a definitive diagnosis?




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Re: IMPA without fever or swelling?
« Reply #1 on: September 10, 2018, 01:35:04 PM »

Hi and welcome

How old is Howdy?  IMPA is more likely to develop in young to middle aged dogs but it is not exclusive to this age group and older dogs, although less likely,  can develop IMPA.

As you have pointed out, IMPA usually comes with a high temperature but this might not be present all the time.  Also, the clinical signs of IMPA develop and increase over time and often it turns from a chronic condition to acute, over many months, resulting in the dog being in so much pain it can  hardly stand or walk.

Given that the x-rays have not shown up any osteo/rheumatoid arthritis, she has shifting lameness and the pain and discomfort is not improving with anti-inflammatory drugs, she has some skin issues but still has an appetite,  this is building up a picture of possible IMPA. 

To obtain a definitive diagnosis of IMPA multiple joint taps have to be performed and the synovial fluid is then analysed. It is not uncommon to trial a course of steroids in the absence of a definitive diagnosis and if in doubt,  the best way to see if immunosuppressive therapy is the right treatment is to give an immunosuppressive shot of an injectable steroid called Dexamethasone.  The duration of Dexamethasone is 48-72 hours.  IMPA usually responds very well to immunosuppressive doses of steroids  and you may see significant improvement within 6+ hours of the first dose.  If this happens then you know that a course of immunosuppressive therapy is the correct treatment and this is usually started about 48 hours after the shot of Dex'.  If there is little or no response to Dexamethasone then there is no harm done because the effects will wear off in a couple of days and there is no need to wean the dog off of steroids. 

If you go down the speculative treatment route and Howdy has a good response and your vet puts her on an immunosuppressive drug protocol, then the best protocol I have come across Is by an eminent professor of immunology called Michael J Day.  See below.

You have nothing to lose by giving Howdy a shot of dex and measure the response.  If you do end up putting her on prednisolone then please give her a gastroprotectant to avoid gastric problems caused by excess acid.


Extract from my seminar notes:

IMPA - Immune Mediated Polyarthritis

Primary Immune mediated polyarthritis is the most common non-erosive polyarthritis in the dog. IMPA can be primary, or secondary to other diseases such as SLE, myositis or meningitis. Symptoms of IMPA can closely resemble Lyme disease or multiple joint infection and this has to be considered in the differential diagnoses.

For a confirmed diagnosis of IMPA, joint taps need to be performed to obtain evidence of infiltrating immune cells within the synovial fluid in the joints.   Clinical signs such as shifting lameness, soft tissue swelling around the joints, difficulty in rising to a stand, stiffness in the neck and back, and very high temperatures etc., can be vague and evident for several months prior to diagnosis.
Clinical signs therefore can be intermittent and initially antibiotic and non-steroidal anti-inflammatory drugs are usually given, but little improvement is seen. The disease continues to progress until the dog becomes quite overcome by the inflammatory process. Also, it is not unusual for the dog to become depressed and anorexic and stand with its head held low, unwilling to move. This is a very painful condition.

Reducing the Tablets
When significant improvement in the dog’s condition is seen, usually between 10-28 days, the initial steroid dose is usually reduced by 25%. The dose is generally given for another 10 - 28 days and depending on the dog’s progress and clinical signs the dose is significantly reduced once more for a further 10-28 days; and again in another 10-28 days. Anecdotal evidence has shown that if at this stage the dose is lowered more slowly, or reduced to an every other day dose over a period of months rather than weeks, relapse are less likely to occur.  It is always tempting to get your dog off steroids as soon as possible, but when treating autoimmune disease, as long as the dog is on a low, every other day dose then taking the last stage slowly seems to work best, depending, of course, on the severity of the disease and allowing for the difference in individual response - no two dogs reactions are exactly the same.  With some autoimmune diseases such as SLE, the dog is likely to be on steroids for the rest of his life. Usually an every other day dose can be achieved, but you risk a relapse if you take the dose too low. Below is the best example of a reducing immunosuppressive protocol I have come across. It is an excellent guide and can be adjusted to the individual.

Example: Reduction Protocol for prednisolone:

Clinical Immunology of the Dog & Cat , 2nd Edition,  by Michael J Day
Professor Michael DayBSc, BVMS(Hons), PhD, DSc, DiplECVP, FASM, FRCPath, FRCVS 

Professor of Veterinary Pathology, University of Bristol, UK and WSAVA - Chairman of Scientific Advisory Committee.

This example is based on a dog receiving an induction dose of 1.0mg/kg/q 12hrs (q = every)
Dose                           Duration (based on clinical effect)
1.0mg/kg/q 12h                          10-28 days
0.75mg/kg/q 12h                       10-28 days
0.5mg/kg/q 12h                         10-28 days
0.25mg/kg/q 12h                        10-28 days
0.25mg/kg/q 24h                        10-28 days
0.25-0.5mg/kg EOD                    at least 21 days
0.25-0.5 mg/kg every third day      at least 21 days

Every reduction is made after consideration to improvement of clinical signs, blood results and side effects of the drugs.
Prednisolone:  "Doses above 2.2mg/kg/day do not give more immunosuppression but do cause more side effects. Many internists believe that prednisolone doses should not exceed 80mg per day, regardless of the dog's weight."  Plumb's Veterinary Drug Handbook Eight Edition.