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Author Topic: Our journey to a diagnosis  (Read 60 times)

Rockdraft

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Our journey to a diagnosis
« on: January 05, 2021, 02:01:38 AM »

I apologize for the long post.
3 months ago our girl Bailey started showing signs of lameness in her back legs. The vet said X-rays showed mild hip displasia and muscle atrophy in one back leg. A 2nd vet felt she may have a herniated disk/disks and sent us to see an orthopedic vet. He felt there was no herniation but said it could be a sprained spine. Bailey continued to get worse. We were referred to a neurological vet who took her off of the anti inflammatory medication she was on and had us return a week later to be examined by her again and a surgeon. They noticed that her front wrists were enlarged and filled with fluid. She suggested  doing joint taps which would tell them what was going on in the joints. The results came back and the diagnosis was IMPA or immune-mediated polyarthritis. Bailey was put on prednisone to bring down the inflammation and Gabapentin for pain. We were advised to follow up with an internal medicine vet who took X-rays, blood work and a urine sample. She confirmed the IMPA and a report from the radiologist showed no destruction of the joint surfaces. The bloodwork came back negative for Lymes disease or tick borne diseases. The urine test did show protein loss so she is putting her on telmisartan, to reduce protein loss and help prevent kidney damage. She also recommended we see a Chinese medicine specialist to discuss any supplements or dietary changes. Since she has been on the increased dosage of prednisone, we have seen  a lessening of the struggle she was having when she tried to stand. There is also a lot less stiffness when she first stands up. Earlier in the week we brought home a couple of toys for the girls and she actually played for about 10 minutes, first time in 3 months. Last night, she chewed on a nylabone for around a 1/2 hour, something she has been doing since she’s a puppy but hasn’t for 3 months. She has started going up stairs occasionally and is wagging her tail again when we come home. She has also been splooting again which is her favorite way to lay.I hope that this is the turnaround we were hoping for. The first picture is splooting.
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Jo CIMDA

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Re: Our journey to a diagnosis
« Reply #1 on: January 05, 2021, 12:49:36 PM »

Hi and welcome

I am sorry that Bailey has IMPA.  The good news is, if it is treated correctly, and brought into remission, then she can lead a normal life again and without pain.  For a dog to have an autoimmune disease they have to have a genetic predisposition.  All is normal until a trigger is met and this induces an immune response that targets the synovial fluid within the joints.  No erosion of the bone occurs and once the immune system is brought under control the body can return to normal function again.  From now on you must limit as many potential triggers as you can.  I will copy some information below.

The correct dosage of steroids and the duration is crucial to the outcome.   The best protocol that I have come across is by Prof. Michael J Day and this can be confidently used as a guide.  If the dose is not high enough or it is given for a shorter duration than necessary you may see an improvement in the clinical signs, but the dog will relapse and not reach full remission.  Although alternative therapies may optimise a dogs condition none that I know of will bring the disease into remission.  Unfortunately, autoimmune disease has to be treated by conventional immunosuppressive drugs.
Below is some information taken from my seminar notes that I hope you will find useful.  A dog that has IMPA may relapse, and then treatment has to be started again, but I have known many IMPA dogs who have, after one or two bouts of IMPA, achieved long term remission and lived a normal, long life without any drugs. 
Best wishes

Jo


What You Should Know About Autoimmune Disease in the Dog
Genetics
It is known that autoimmune disease in the dog occurs in animals that are genetically predisposed. This means that they have an inherited risk of developing autoimmune disease.  It is thought to be a complicated mode of inheritance involving more than one gene; this is known as polygenic. Both parents carry the genes responsible and it does run in families, but this does not necessarily mean that if one dog in a litter gets an autoimmune disease the others will also follow.  This is possibly due to the different mix of inherited genes in individual pups in a litter, or environmental factors (potential triggers).  Unfortunately, at the moment, there are no DNA tests for these diseases.
It is not known why dogs with a genetic predisposition develop a specific autoimmune disease or indeed develop more than one autoimmune disease.  It may be due to the combination of inherited genes (or lack of them); different environmental influences; or a particular set of untimely circumstances that triggers specific diseases in a predisposed dog.
Age
It is more likely to occur in a young to middle aged dog, but occasionally dogs as old as 14, or more, have been known to develop an autoimmune disease.
Gender
Females seem to be more prone - and this probably due to hormonal influences. Also, it is known that hormones can be a major trigger factor for autoimmune disease in the dog, as in humans. 
So, for a dog to develop an autoimmune disease it needs to have a genetic predisposition, but that’s not all, as it would have to encounter a `trigger’ that causes the immune system to malfunction.
So what are trigger factors?
Anything within your dog’s environment that may challenge the immune system can be a potential `trigger’.  A dog that develops an autoimmune disease may have encountered the same trigger factor before, with no detrimental effect, but for some reason `on this occasion’ it has caused the immune system to malfunction resulting in the dog developing an autoimmune disease.
Possible trigger factors are:
1.   Stress eg., fireworks, thunderstorms, separation anxiety, whelping, hormones etc.
2.   Viral or bacterial infection.
3.   Reaction to chemicals, drugs or vaccines.
To sum up:
A primary autoimmune disease may occur if a genetically predisposed dog encounters a trigger factor that causes the immune system to become confused and mounts an attack on its own body parts or systems.
How do you control the immune system and get it to behave normally again?
Drugs, predominately steroids, are used to significantly suppress the immune system in order to stop the destruction and allow the body to heal and work normally again. When clinical improvement is seen, the drugs are reduced over a period of time, slowly releasing the immune system back to normal function and, hopefully, achieving a state of remission.  There is no cure for autoimmune disease but long term remission can be achieved. Dogs may have an autoimmune disease only once and never get it again but there is always a possibility that a predisposed dog could relapse or get another autoimmune disease at a later date. Some dogs will stay in remission without any drugs and others will have to be controlled on a low, every other day maintenance dose. 

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.

The Importance of Correct Treatment and Dosage

Iatrogenic Cushing’s syndrome may also occur if the vet has initially prescribed a dose too high for the size of dog being treated.  For example:  I received an email from the owner of an Irish Setter, with AIHA.  The dog was prescribed 200mg of prednisolone each day. I called the owner, only to hear that the dog had to be put to sleep that day.  I was not surprised. The poor dog was on nearly twice the highest, recommended dose of prednisolone.  She was 9 years old and had never had a day’s illness in her life.  What a terrible shock for the owners and what a lot of unnecessary suffering.  I know what it feels like because I too, have lost a dog due to prescribed overdosing of prednisolone.  The feelings of responsibility are enormous.
In contrast, some dogs are not treated with enough prednisolone.  Here’s another story:
A greyhound diagnosed with immune mediated thrombocytopenia (IMTP).  Her vet gave her an initial shot of dexamethasone (a steroid which is 6 times stronger in terms of glucocorticoid activity than prednisolone).  Some vets choose to give a shot of ‘Dex’ as an initial therapy in autoimmune disease, especially if the patient is acutely ill.  Its effects can sometimes be seen within 6 hours and lasts for 36-72 hours.
The vet did really well and a marked improvement in her clinical signs was seen. It is usual, 24 to 48 hours after the shot of Dexamethasone for the treatment to change to an immunosuppressive dose of prednisolone tablets and for the owner to continue treatment in the usual way.  However, the vet only prescribed 5mg of prednisolone a day. The owner said they were very concerned that after a few days of improvement, she seemed to be very poorly again.  The vet couldn’t understand why she was not continuing to improve.  He gave her another shot of Dexamethasone and the same improvement was seen.  I suggested to the owner that she either spoke to her vet about putting her dog on an immunosuppressive dose of prednisolone or change her vet.  They saw another vet in the practice, who was more experienced in treating autoimmune disease, and the dog was put on the correct, immunosuppressive dose of prednisolone and the treatment was successful.
These case histories demonstrate how important it is to treat promptly and correctly.

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.

A gastroprotectant should be given to protect the stomach from the excess acid that the steroid produce.
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