mistaken diagnosis

[TedTheMaineCoon]

Hi

I’m just wondering if myositis can be mistaken for PMR ? I am asking because 2 GPS say i have PMR , 1 doctor says I haven’t and rheumatologist says she’s not sure !

Some of the symptoms are the same apparently.

[Purpleprimate]

I was told I had PMR, but now apparently I have Myositis, which even after a muscle biopsy they say is not conclusive! So I've been taking steroids for 3 yrs which is not good, but being tried on Mycophenolate so I can reduce them. I'm told that one type of immune disease can segue to another. Anyway my legs hurt - sometimes a lot!

[TedTheMaineCoon in reply to Purpleprimate]

Funny you should say that , because I think I have myositis & maybe lupus . Yes I I have terrible leg pain too .

[TedTheMaineCoon in reply to Purpleprimate]

Do you get very painful armpits ? Which is what I’m experiencing

[Purpleprimate in reply to TedTheMaineCoon]

No, really just legs I think, as any other aches & pains are probably down to age. I would like to get a clear diagnosis as there are different types of myositis. I need to get off the steroids too as some people say they are not too bad for you - but if you take them for sometime they definitely are.

[Tiggywoos in reply to TedTheMaineCoon]

I get the painful arm pits 😣

[SoonToBe]

steroids themselves can cause chemical myositis together with all the other side effect-

[Wytchylady]

I was misdiagnosed with PMR before being diagnosed with SLE (Lupus). Myostosis has been a long standing problem for me, linked to the Lupus. If you don't agree with the PMR diagnosis keep pushing. Keep a diary of symptoms and push for blood tests that can be an indicator of Lupus.

[TedTheMaineCoon in reply to Wytchylady]

Thank you so much for the support ! I’ve had the butterfly rash on several occasions &’once in A&E , but no one listened to me. But I will push it when I see the rheumatologist in 2 weeks, as it’s been getting me down so much lately !

Regards

Lesley

[Wytchylady in reply to TedTheMaineCoon]

If you can take a photo of the butterfly rash and any other rashes. Other than the Rheumatologist who diagnosed me I've only ever had one other doctor recognise a Malar rash.Also there's Lupus UK, the charity. I joined for support. There's a mine of information and people who understand.

Most people with autoimmune conditions have a collection or crossovers.

Regards

Sue

[TedTheMaineCoon in reply to Wytchylady]

Thanks Sue for being so helpful.

I’ll check that site out Lupus uk 👍🏼

[Wytchylady in reply to TedTheMaineCoon]

You're very welcomeRegards

Sue

[Purpleprimate]

I was initially diagnosed with PMR & treated for that over 2 yrs. Saw a new rheumy who said he thought I actually had Myositis which tests have shown is probably the case - the biopsy was non-diagnostic probably due to long term immunosuppression, the EMG 'demonstrated clear myopathic changes' Diagnosed with 'presumed seronegative myositis' which I have yet to find out precisely want that means. If anyone knows please let me know. When I enquired how it was I had PMR & now I have Myositis I was told there can be crossovers.

Yet to understand precisely what the diagnosis is & the outlook for the future.

Just seen I've posted on her before & forgotten all about it.

[TedTheMaineCoon in reply to Purpleprimate]

Thanks for your post ! I’ve been suspicious of my PMR being myositis. Apparently it has been suggested that statins can cause myositis. Which I’ve been on for years . Whether it’s proven or not, I don’t know .

Do you know if there’s a specific blood test or any test to prove myositis ? Wondered if I should go private .

[SoonToBe in reply to TedTheMaineCoon]

Yes the link to statins is well proven but not all who take them develop HMGCR autoimmune mediated necrotizing myopathy. The easiest way to check is to request a myositis panel (blood test which consultant can request on NHS), this will identify all baring two forms of idiopatic myositis (the two it can't detect are chemical induced myositis, which is often induced by steroid usage, or seronegative,necrotizing myopathy, which is caused by unknown antibodies,

[TedTheMaineCoon in reply to SoonToBe]

Thank you so much for this info’ . I’ve just had an appointment come through to see rheumatologist on Wednesday! So will ask her about the myositis panel .

Kind Regards

Lesley

[Purpleprimate in reply to SoonToBe]

First it was thought I had necrotising myopathy, but now seronegative. Are you able to explain what they are because no one else has? Or maybe you could point me to some info. The Mycophenolate I'm taking after nearly 4 months does not seem to have made any difference to my symptoms & my hair is falling out so I might just stop it. You say myositis is often induced by steroid usage. Does that mean having taken Pred for PMR that could have then led to me now having Myositis?

The seem well informed.

Thanks.

[SoonToBe in reply to Purpleprimate]

Not certain what you are exactly looking for but try these links (yes they are American but are good sources of information and much better than any UK site). understandingmyositis.org/ & myositis.org/.

As to the types of necrotizing myopathies - Seronegative just means the antibody that causes it has not been identified. The other 2 types of necrotizing myositis are caused by two antibodies, anti-SRP and anti-HMGCR. The second of these, anti-HMGCR, is often, but not exclusively, link to the use of certain statins.

As to your biopsy 'being non-diagnostic' I am not certain what you mean? If it means your biopsy was inconclusive that is sometimes the case as it is not simple to read these or decide which muscle to sample.

As to steroid induced myositis it is an elephant in the room - it is not often discussed as whist a side effect its occurrence is less common than the well know ones. Along with all the well known issues, weight increase, diabetes, high cholesterol and osteoporosis, it can also induce myositis. It was a whispered topic during my last neuromuscular consultation - lets get you off the steroids as they could be adding to your issues due to chemical myositis. It is not often discussed even though the leaflet included with them state 'muscle weakness' can occur.

Did you have an MRi? This would show degree of muscle loss/inflammation.

You should also be aware other things can cause myopathies (immunosuppressants may have no impacts of these) - for example genetic issues like myofibrular myopathy (5 type known each caused by different genetic defects).

Note: for me methotrexate had not impact, ritexumab was need to control my anti-SRP.

[Purpleprimate in reply to SoonToBe]

'Being non-diagnostic' I'm presuming was that they couldn't make any diagnosis - 'This is likely to be related to his long term immunosuppression'. I had an MRI previously so they decided from that where to take the muscle biopsy from. My initial diagnosis was necrotising myositis but they have not been able to confirm this, hence 'presumed seronegative Myositis'. My brother, when a teenager had Reiter's syndrome brought on by a virus & dependant on having a gene HLA-B27. My other brother has psoriatic arthritis.

Although my NHS consultant neurologist & rheumatologist both appear well informed & very competent I need to get another Neurologist's opinion I think, so will look for one privately. I live in London UK so any suggestions very welcome.

I was tried on Methotrexate way back, which had similar side effects to the Mycophenolate I'm taking now , in that my hair thinned & I felt no better.

[SoonToBe in reply to Purpleprimate]

A lot of the 'cancer/immunosupressent' drugs can lead to hair loss in some people. Most drugs used for myositis are immunosuppressive in nature.

As to the biopsy it sounds like the use of immunosuppresents is working as the could not see the normal myositis signs as inflammation and immune system effects where not seen. The issue seems to be the hair loss these cause. You do not note if they ran the myositis blood panel but I assume they did to state you were seronegative?

Its worth noting that many people who's myositis is 'under control' suffer aches, pains and weakness - these need to be trended over time to determine if getting worse. I'm still active in the US support organizations for these illness and these are the number one complaints most sufferers have (US population of suffers is much larger then the UK one due to population size).

The big issue with the necrotizing ones is any dead muscle is replaced with fat if left untreated long enough and when this happens you can never regain this muscle - the weakness is permanent. All you can do is strengthen what is left. Some physicians will give you false hope by saying you can gain your strenght back - of the 100 plus necrotizing sufferers I know from the US only 1 or 2 regained their pre-illness strength, these were those who got rapid treatment.

Following British Society of Rheumatology guideline the treatment, if the 1st and 2nd line treatments failed (steroids, then methotrexate/Mycophenolate and a few others) is Ritexumab (knocks out b-cells so antibodies are not produced) and/or IVIG are the suggested options (note the latter will only be authorized if you are no longer mobile and you'll have to push for Ritexumab as it makes you prone to infections) - I assume these have not been tried? These are similar to the recommendations of The National Institutes of Health in Washington DC, USA (NIH, they have an expert team who liaise with John Hopkins Hospital and are seen as some of the world experts on inflammatory myositis). My diagnosis has been confirmed by 3 independent teams, my original US neurologist, NIH and NHS.

As to suggesting a London expert I'm based in Lincoln UK and am seeing a neuromuscular specialist at the Queens Medical center in Nottingham (he is attached to Nottingham University). No knowledge of experts in the Home Counties. Dr Chinoy in Manchester is seen as one of the UK's top experts in muscle diseases.

[Purpleprimate]

Yes, it would appear that the Pred is working as they could see nothing on the biopsy, hence 'non-diagnostic'. The EMG 'has demonstrated clear myopathic changes. There may also be some superimposed lumbar & cervical radiculopathy' - whatever that means. They have taken numerous blood tests. Whether the myositis is 'under control' I'm not sure, probably not, as my muscle weakness & pain has become worse - my balance is definitely worse & I've fallen on a number of occasions.

I do walk for aprox an hour most days but I think I need to do more to stop my muscle degradation, although when you're hurting it's not what you feel like doing.

I have been put on the Mycophenolate to get me off the Pred having tried Methotrexate when it was thought I had PMR which I came off very quickly as it just made me feel bad. So it would appear I need to try & get someone to try me on Ritexumab.

Will look at the US website you suggested.

Very many thanks for your advice.

[SoonToBe]

radiculopathy is a pinched nerve - it in its self can cause pain (siatica results from this when this effects the legs). So the biopsy results means they saw no Myositis related changes - dependent on how quickly from onset this was taken it would still show muscle damage if it was the necrotizing form (this causes muscle death). A MRi would also show muscle replacement with fat if the necrotizing form. This would still be there in the biopsy even if the Myositis was under control. Im not a medical expert but based on what you have said it does not look like necrotizing myopathy - could be one of the other forms though.

[Purpleprimate in reply to SoonToBe]

The MRI report:

lower limb showed intramuscular oedema of the abductor magnus & hamstring muscles of both thighs, the gastrocnemius muscles & soles muscles bilateral & both tibias anterior muscles. The quadriceps muscles & gracilis muscles are spared. The appearances are suggestive of immune mediated myopathy IMPP or HMG-CoA.

An MRI 4 months later showed: relatively stable appearances with perhaps slight improvement in the oedema within the hamstring muscles.

The problem is they don't really have the time to explain to you precisely what all these results mean. I will go & see someone privately so I can go through everything.

What will allow me to be prescribed Ritexumab on the NHS & are there side effects to worry about?

Thanks.

[SoonToBe]

One comment on MRi - did it show any muscle loss or fat replacement of the muscles? These are common in NAM (needs the correct MRi to be run, it is not a 'standard' MRi, I believe this is called a T2 or STIR MRi). It also needs more specialized knowledge to analyze it (NHS had to run 2 separate MRi's on me and send the second for external analysis, as the local team did not have the required knowledge, the first one was not run correctly due to lack of clear communication). Oedema only really shows inflammation is present. Plus NAM normally impact proximal muscles first, most you highlight are distal. Have they considered myofibrillar myopathy (a rare form of muscular dystrophy) or similar?

You'd have to show signs of active necrotizing myosotis not controlled by other treatments (methotrexate etc.) to get Ritexumab infusion. If it any other myositis then it may not work. It is not particularly cheap so may have to self advocate. You'd also need to find a clinician who is willing to prescribe it (I pushed mine as I have evidence that its worked for me and methotrexate did not, I also had 3 independent NAM diagnosis). Its biggest 'side effect' is that it knocks out part of the immune system, it actually works by stopping antibody production by preventing b-cell generation. This means you become susceptible to any infections going around (I have been on it 1 year and only had one mild COVID bout, yes I'm fully up to date on vaccinations, and one chest infection following a bad cold). Its an infusion which takes 2 doses two weeks apart initially, each which take 3-6 hours each (depends on how well you tolerate it). There are a number of other side effects (search it on drugs.com to find all of these). Some people can have allergic reactions to it, which generally occur rapidly during the infusions or within 24 hours. After the 1st two doses it lasts anything 6-12 months (UK uses b-cell levels to determine when another dose is needed).

In my case they ran it at full speed (3 ½ hrs. per infusion, after 1st one) and I had no side effects.

[Purpleprimate in reply to SoonToBe]

Soon to Be, there is quite a lot there for me to take in! 'My' Neurologist recently spoke to me & I'm having another MRI. I explained to him I didn't think the Mycophenolate was really making any difference. He said of 100 of his patients on the drug none had experienced hair loss that he is aware of, although it does come up as a side effect. I have lowered my dose to 500mg a day (without telling the consultant) & the itching I've had in my scalp has gone away, although I will up the dose again to 1 gram a day. He did mention Ritexumab but said it had to be agreed by a 'panel'. Once the MRI has been analysed will see where this goes. I'm going to go through your last post carefully so that I can ask the consultant all the right questions & will let you know how things go in due course.

Many thanks again.

[SoonToBe]

yes ritexumab has strict rule for use in UK. But it will also depend on your consultant. I was initially under a rheumatologist when I came back to UK and they only wanted to use steroids ( currently have case open with Ombudsman as this does not follow British Society for Rheumatology guidelines). Switch on a more major hospital and neuromuscular specialist who instantly suggest ritexumab and was willing to push for it and indicated it would not be a problem.