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Author Topic: Myositis, relapse and treatment advice needed!!  (Read 155 times)

kateandmoose

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Myositis, relapse and treatment advice needed!!
« on: August 02, 2020, 01:53:57 PM »

Hi everyone!

My 2 year old whippet x, Moose, was diagnosed with Myositis a couple of weeks ago. He started on 25mg steroids then dropped to 12.5mg, and has been very quickly dropped to 10mg every other day two days ago. His symptoms have come back (including a balding around his muzzle - we don't know if this is a symptom too?) and we have had to start giving him calpol again for the pain. Not good!!

Will be heading back to the vets tomorrow but are considering taking him to a specialist (we live in York if anyone has any recommendations) - thoughts? Also, any other advice on treatment or questions to be asking our vet would be hugely appreciated!!

Thank you in advance!!

Kate x
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Catherine

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Re: Myositis, relapse and treatment advice needed!!
« Reply #1 on: August 02, 2020, 02:43:24 PM »

How much does Moose weigh? He needs to be on the correct dose. It sounds as though his medication was reduced too quickly. Here is a good medication protocol:

Immunosuppressive Protocols for Oral Prednisolone in the Dog.
Ref: Clinical Immunology of the Dog & Cat by Michael J Day  – 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/q12hrs (every 12 hours)

Dose                Duration (based on clinical effect)

1.0mg/kg/q12h             10-28 days
0.75mg/kg/q12h            10-28 days
0.5mg/kg/q12h             10-28 days
0.25mg/kg/q12h          10-28 days
0.25mg/kg/q24h          10-28 days
0.25-0.5mg/kg/ Every other day      at least 21 days
0.25-0.5 mg/kg/ Every third day       at least 21 days

Azathioprine (a cytotoxic drug) can be used in combination with prednisolone at 2mg/kg/24 or 48 hrs and dose gradually reduced, when remission is achieved, over a period of months.
Clinical response to Azathioprine may take up to 6 weeks. (Plumb’s Veterinary Drug Handbook)

Don't forget the gastroprotectant!

Also you can see some posts regarding myositis which you may find helpful, using the search facility on the site.

If your vet (or indeed you) are not confident about their experience with the illness then a specialist would be a good idea.

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Jo CIMDA

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Re: Myositis, relapse and treatment advice needed!!
« Reply #2 on: August 02, 2020, 06:39:08 PM »

Hi Kate and welcome

I am sorry Moose has myositis.  I presume this was diagnosed by having muscle biopsies, and that the improvement was very good once started on the prednsiolone?

Like Catherine says, the preds were reduced too soon and this is why you are seeing the return of clinical signs.  For any inflammatory autoimmune disease the dose and duration of immunosuppressive treatment is crucial to the outcome.  The protocol that Catherine has copied is the best immunosuppressive protocol that I have come across and it can be confidently used as a guide.  If the dose is not high enough, or the duration is not long enough, long term remission will not be achieved and relapses will occur.

In a way, taking Moose to see a specialist is not really necessary.  As long as the diagnosis of an inflammatory AI disease is correct the treatment is the same - that is with immunosuppressive doses of prednsiolone and perhaps a combination drug such as mycophenolate, cyclosporine, leflunomide etc..... At this stage the introduction of Azathioprine (another potential combination drug)  is not a good idea because it takes many weeks to reach its full potential. See this link:
 
https://www.dvm360.com/view/immunosuppressive-drugs-beyond-glucocorticoids

As Moose has already has some build up of prednsiolone over the last couple of weeks, it might be prudent to introduce another drug to support immunosuppression, and also so that you can start to reduce the preds a bit earlier without reducing immunosuppressive effect.   One of the side effects of preds is muscle weakness and, especially with a myositis,  the addition of another drug will help to reduce this unwanted side effect.

Moose should also be on something like omeprazole to protect his stomach from the excess acid that the steroids produce.

Once the preds are increased back to an immunosuppressive dose, and given for the correct duration, and slowly reduced over a period of many months (especially if you add another immunosuppressive drug)  Moose  should quickly improve again and achieve remission.

Good luck with your vet.

Jo

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kateandmoose

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Re: Myositis, relapse and treatment advice needed!!
« Reply #3 on: August 03, 2020, 09:31:30 PM »

Hi Jo and Catherine,

Thank you so much for your reply!! I really appreciate all the help from both of you.

He was not diagnosed via biopsy but via symptoms and the vets sent off for bloods to confirm (should be getting them back at the end of this week). We don't know which bloods have been done but we think it's antibodies to type 2 M. Should they have done CK, FBC (eosinophils) and U and E's as well? Do we still need a biopsy if the bloods are positive?

We have noticed a loss in fur around his muzzle and wonder if this is a symptom of the disease or treatment? The vets believe he has masticicatory myositis.

What dose of omeprazole should he be on? He weighs 24kg.

Which other immunosuppressant would you recommend and what monitoring would it need?

We are concerned that he has been dropped far too quickly. At the start of his third week on prednisole he is on 10mg every 2 days. Even at the start of his steriods he was on 25mg every day but from the look of your table he should be on 24mg twice every 24h, and should have been on this for a lot longer. Do we need to ask to start the course again?

At what point should I seek a specialists' advice? We live near York, are there any you would recommend? We have been suggested Liverpool Teaching Hospital by a friend?

Thank you so much in advance!!!
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Jo CIMDA

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Re: Myositis, relapse and treatment advice needed!!
« Reply #4 on: August 04, 2020, 09:43:22 AM »

Hi Kate

When you first visited the vet, was Moose able to open his mouth without pain? 

The symptoms of  Masticatory muscle myositis  (MMM) pretty much give a good indicator of the disease.  The mouth is unable to open very much and there is intense pain.  Also the dog is unable to bark because of the restriction of the mouth.  The muscles on the head will reduce considerably and you will be able to see the formation of his bones.  Masticatory myositis is confined to the head muscle but a generalised myositis can also occur and this affects any other muscle in the body.

The only way to definitively diagnose MMM is by a biopsy of the muscles affected.  The blood tests only indicate inflammation or infection and they are not specific.

To treat an autoimmune disease the dose of prednisolone has to be immunosuppressive, anything less and it will not suppress the immune system enough to bring the disease process under control and achieve long term remission.
 Moose was on an anti-inflammatory starting dose of pred and although this may well have shown a positive response it will not last, and as you have found out, the symptoms will return.  The object is to treat with the correct dose of steroids (and/or other immunosuppressive drugs) for the correct duration of time, in order to stop the immune cells from targeting the masticatory muscles and return to normal function, thereby achieving remission.   

For an autoimmune disease to develop, the dog has to have a genetic predisposition, which then has to be triggered by something within the environment, vaccines, chemicals, stress, hormones etc.,   So when the dog has achieved remission it will stay in remission as long as it doesn't meet another trigger. This is something you will have to consider when Moose is better.

If Moose is showing clinical signs similar to when this started, then you can assume a relapse has occurred and an immunosuppressive course of treatment has to be started from the beginning.  The protocol that Catherine  quoted is the best protocol that I have come across and it can confidently be used as a guide. If Moose receives any less than 1mg/kg/12hours prednsiolone then the treatment will not work.  By adding another immunosuppressive drug you will likely be able to reduce the preds a little quicker.  Mycophenolate Mofetil has had excellent results and the lead in time isn't long, which is a bonus.  It is likely that your vet will have other drugs that he may be more familiar with and would prefer to use.

Liverpool Teaching hospital is a very good referral hospital.  The only problem that you have now is they will likely want to biopsy Moose and because he is on prednsiolone this cannot be performed for at least a couple of weeks after the withdrawal of prednsiolone because the effect of pred will mask results.   Your vet could call the hospital, or any of the good vet schools, such as Glasgow, RCV, Cambridge, and ask for advice and see what treatment they recommend.

I hope you will be able to work with your vet  on this.  If the symptoms fit MMM, and there was some improvement when giving steroids, then a biopsy shouldn't be necessary.  Often when an AI disease is suspected, and a definitive diagnosis isn't reached, speculative treatment with immunosuppressive doses of prednsiolone is given and if the desired response is seen then the diagnosis is assumed. 

Jo





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Jo CIMDA

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Re: Myositis, relapse and treatment advice needed!!
« Reply #5 on: August 04, 2020, 09:48:36 AM »

P.S.

The dose of omeprazole is as follows:

Dogs:

For GI ulcer management/prevention:   Usually dosed at 0.5-1mg/kg once daily.  Practically rounding to the nearest 10mg within this range.
Ref:   Plumb's Veterinary Drug Handbook, Eighth Edition.



It is best to give other medication one hour before omeprazole,  or two hours after omeprazole administration,  to avoid it inhibiting the absorption other drugs.
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