Inflammatory myopathies (myositis)

The inflammatory myopathies are autoimmune conditions. The immune system, whose job is to fight infection, turns on the muscles instead, inflaming them, and the weakness follows from that inflammation. The inflammation of polymyositis is within the muscle fibres; in dermatomyositis it also involves the small blood vessels that supply the muscle and the skin. In most cases nobody knows why this happens; genes and something in the environment are both thought to play a part.

Any age can be affected, though adulthood is when it tends to appear, and dermatomyositis is roughly twice as common in women. Another autoimmune condition, lupus or systemic sclerosis for instance, is sometimes present alongside it, within the wider group of connective tissue disease. An underlying cancer is sometimes found, with dermatomyositis in particular, so the assessment considers that risk in everyone and includes screening tests where it is higher.

Muscle weakness is the defining symptom, and it usually builds over weeks to months. The picture can include:

• The large muscles losing strength: thighs, hips and shoulders, for instance
• Everyday movements becoming hard, whether that is stairs, getting out of a chair or raising the arms
• For some people, muscles that ache or are tender to the touch
• With dermatomyositis, skin changes alongside the weakness, a distinctive rash in particular
• Tiredness on occasion, or other parts of the body affected

Several sources feed the diagnosis: your own account, the findings on examination, the blood tests for muscle enzymes and for the antibodies particular to myositis, and, when they are called for, further investigations such as scans or studies of the muscle itself. Muscle weakness has many possible causes, which is why a thorough assessment matters before the diagnosis is confirmed.

Painful joints can be scanned as well. Point-of-care ultrasound is part of the consultation with Dr Borukhson; it can help in judging whether a joint is inflamed (the ultrasound clinic page gives the background).

The treatment aims to quieten the immune-driven inflammation, to restore and protect the strength of the muscles, and to deal with any other part of the body that is involved. Getting the inflammation under control is the first job, and a corticosteroid, prednisolone as a rule, is often what does it. To bring the steroid dose down over time, a steroid-sparing medicine that calms the immune system, methotrexate, azathioprine or mycophenolate for example, is often added, and for selected people immunoglobulin (IVIG), given as an infusion, may have a part as well. Each is used with a specialist supervising, and each is gone through with you fully.

Each of these medicines brings its own precautions: with steroids over a long period the bones have to be protected and things kept under review, and with an immunosuppressant there are regular blood tests, and the chance of an infection can rise. The treatment is adjusted to the person and reviewed as it goes along, often with physiotherapy running alongside it to help strength return, and with a speech and language therapist where swallowing is affected. You and Dr Borukhson settle the plan together.

Muscle is what the heart is made of, so in some people the inflammation reaches it as well, in the heart muscle itself (myocarditis) or in the rhythm it keeps. Inflammation there can weaken the heart. That is why a blackout, palpitations happening now that will not settle, or that arrive with chest pain, breathlessness, faintness or a faint at the same time, a severe struggle to breathe (gasping, choking or no breath for words), or chest pain that is crushing, tight or like a pressure, that spreads to an arm, the jaw, the neck, the stomach or the back, that comes with breathlessness, sweating, feeling sick or feeling light-headed, or that came on suddenly and does not go away, is a 999 or A&E emergency, as the When to seek help section says, and why, short of those, new chest pain, breathlessness that is new or getting worse, palpitations, or tiredness far beyond what the muscle symptoms would explain needs an assessment the same day rather than being blamed on the myositis (in pregnancy, breathlessness that comes on suddenly, or when you lie down, or with dizziness, is for your midwife or maternity unit straight away). Should cardiology be needed, it joins the care. Checks on the heart belong in the routine care of adults with myositis, blood markers, an ECG and an ultrasound scan of the heart among them, and the heart can be affected in any phase of the condition, even when the muscles are quiet, which is why it is looked at whether or not they are active. The reasons, and the checks to ask about, can be found in the inflammation and your heart guide.

Myositis does not always confine itself to the muscles, and when it reaches further the care can call for other specialties as well. Dr Borukhson practises within a world-renowned tertiary centre, with ready access to consultant colleagues in the other specialties this condition may call on. Where it helps, she can bring those specialists in directly, and particularly complex cases can go to a multidisciplinary team meeting (MDT) with minimal delay. Whenever more than one kind of expertise is needed, the strands of your care can be drawn together and decisions reached promptly.

Strength comes back slowly, and while it does, pacing your activity matters. Do the exercises your physiotherapist gives you, but do not push through tiredness: when it sets in, rest. Exercise is safe in myositis and helps function return, so regular movement, tailored to you and built up gradually, is part of the treatment.

Alongside that:

• Keep the sun off your skin if you have dermatomyositis, since sunlight can set off a flare of the rash, and of the muscle disease too
• Eating well, and calcium and vitamin D where your team advises them, help to protect bone during steroid treatment, and regular movement within your limits protects muscle
• Keep up the vaccinations your team recommends, telling whoever gives them which medicines you take
• Get a fever or an infection assessed the same day, as the next section says, because the medicines can weaken your body's response to it, and the same goes for contact with measles, chickenpox or shingles

Should you want to start a family, talk to your team first: the best time is when the condition is quiet and you are on medicines that are safe in pregnancy, and methotrexate and mycophenolate are stopped before you try, on the timetable your team gives you; our guide to arthritis, autoimmune conditions and pregnancy has the detail.

Useful strength comes back for many people, and with it their normal routine. Between appointments, keeping in touch lets the plan move with you.

A few symptoms cannot wait for your next appointment, and some cannot wait at all.

Treat any of these as a 999 or A&E emergency: call 999 and do not drive yourself to A&E.

• Severe illness with suspected sepsis: a high fever with shaking, confusion, rapid breathing, or feeling dramatically worse over hours
• With a fever or feeling unwell, a rash that does not fade when you press it, a stiff neck with eyes that cannot bear bright light, or skin, lips or tongue turning blue, grey, pale or blotchy, since these can be signs of meningitis or sepsis; on black or brown skin the rash and the change of colour may be easier to see on the palms of the hands or the soles of the feet
• Chest pain that is crushing, tight or like a pressure, that spreads to an arm, the jaw, the neck, the stomach or the back, that comes with breathlessness, sweating, feeling sick or feeling light-headed, or that came on suddenly and does not go away
• Breathlessness that is severe, with gasping, choking or no breath to get words out; or coughing up blood, since the lungs and the heart can both be involved
• Palpitations happening now that do not stop, or that come with chest pain, breathlessness, feeling faint or fainting, since a heart whose muscle or rhythm is affected has to be checked at once
• A blackout, since the heart's rhythm can be disturbed when the inflammation reaches it
• Choking that will not clear, or breathing that is failing
• Sudden weakness or numbness on one side, a drooping face or difficulty speaking, a sudden severe headache, sudden confusion or a seizure, or sudden loss of vision, any of which can be a stroke, even if it stops after a short time
• An eye that suddenly and completely loses its sight
• Sudden severe pain in the abdomen or back, since the pancreas can react to prednisolone
• Lips, mouth, throat or tongue that suddenly swell, a throat that feels tight, very fast breathing or a struggle to breathe or to swallow, skin, tongue or lips turning blue, grey or pale (on black or brown skin this may be easier to see on the palms of the hands or the soles of the feet), becoming suddenly very confused, drowsy or dizzy, or fainting and not being able to be woken, since this can be a severe allergic reaction, anaphylaxis, which can follow a dose of any medicine
• Vomiting blood, or bleeding from the back passage that is heavy or will not stop, most of all with faintness, confusion or pain in the abdomen, or vomit that is black or dark brown, since a stomach ulcer on prednisolone can bleed
• Thoughts of harming yourself or ending your life, which steroids can bring on

Any of these needs an assessment that is urgent, on the same day, from your GP, your rheumatology team or NHS 111:

• A fever, or feeling generally unwell, on immunosuppressant, biologic or steroid treatment, since an infection has to be treated early
• A joint that is hot and swollen, with a fever or feeling unwell, since an infected joint has to be ruled out at once, at A&E or through NHS 111
• A joint that has become hot and very swollen suddenly, or is worsening quickly, even without a fever, since an infected joint does not always announce itself with one; a joint that will take no weight at all, or that cannot be moved, is a 999 or A&E emergency, whether or not there is a fever
• New chest pain, new palpitations, or breathlessness that is new or getting worse, or tiredness far out of proportion to your muscle symptoms, since the heart can be involved, and so can the lungs; palpitations happening now that do not stop, or that come with chest pain, breathlessness, feeling faint or fainting, belong to the first list; in pregnancy, breathlessness that comes on suddenly, or when you lie down, or with dizziness, is for your midwife or maternity unit straight away, as the pregnancy line below says
• A persistent dry cough with a fever, with new breathlessness, or that is worsening over hours to days
• A new red, painful eye, or sight that has blurred, dimmed or changed, which needs an eye casualty or urgent eye clinic the same day, as does an eye that light hurts; in pregnancy, any change in sight, blurring or flashing lights among them, is also for your midwife or maternity unit straight away, as the pregnancy line below says, since it can be a sign of pre-eclampsia
• Difficulty swallowing, episodes of choking, or weakness getting worse fast, since the muscles of the throat can weaken, sometimes before the limbs do, and food or drink that goes down the wrong way can cause a chest infection; where swallowing has long been a problem, it is a change in it that counts
• A calf that is swollen, hot or painful, or a limb that is painful, swollen or discoloured, which can mean a clot, even where the muscles already ache from the myositis, when one calf or limb has swollen, changed colour or begun to hurt in a new way; with breathlessness, chest pain, palpitations or feeling faint, this is a 999 or A&E emergency: call 999 and do not drive yourself to A&E
• A marked change in mood or behaviour, confusion, or seeing or hearing things that are not there, on steroid treatment, since prednisolone can do this, the more so the higher the dose; confusion that comes on suddenly is a 999 or A&E emergency, as the first list says
• Unusual thirst or hunger, passing urine more often, or feeling sleepy or confused, on steroids, or swelling of the arms or legs, bruising or bleeding that is not normal, black or dark red stools, severe stomach pain, severe back pain, a severe upset stomach, being sick, or very bad dizziness, since each can be a steroid effect that needs checking without delay; pain in the abdomen or back that comes on suddenly and severely is a 999 or A&E emergency, as the first list says; in pregnancy, bleeding that is not normal, and stomach pain that is severe, belong to the pregnancy line below
• Contact with measles, chickenpox or shingles, since these infections can be severe on steroids and a medicine to protect you may be needed
• Being near someone with measles, chickenpox or shingles, while you take a medicine that weakens the immune system, since measles and chickenpox can be dangerous when the immune system is weakened, and you can catch chickenpox from someone with shingles if you have never had chickenpox; NHS 111 can tell you what to do that day
• In pregnancy, any bleeding, stomach pain that is severe or does not go away after a rest, reduced baby movements, a severe headache or visual disturbance, sudden swelling of the face, hands, legs or feet, or breathlessness that comes on suddenly, or when you lie down, or with dizziness: contact your midwife or maternity unit straight away, whatever the time; bleeding that is heavy, or that comes with severe pain in the tummy, pain in the shoulder, or feeling sick, faint or dizzy, or passing out, is a 999 or A&E emergency: call 999 and do not drive yourself to A&E; pain in the abdomen or back that comes on suddenly and severely is a 999 or A&E emergency, as the first list says
• A high temperature in pregnancy, whatever medicines you are taking, since a fever can be a sign of an infection that needs checking; your midwife or maternity unit can advise

A persistent dry cough on its own, or breathlessness that has drifted slowly, over weeks or months, is something to tell your team promptly, without waiting for a routine slot. New falls, or weakness that is clearly advancing week by week, need the same prompt call to your team, unless the weakness is worsening fast or the falls come with it, which is the same-day sign above.

Weakness that is slowly returning, new skin changes in someone who otherwise feels well, or side effects from the medicines, short of the signs in the two lists above, are reasons to contact your specialist team for a routine review rather than emergency care. In pregnancy, a new rash or skin change is not for that routine review: ring your midwife or maternity unit, or your GP, straight away, as an infection that could harm the baby has to be thought of first; our pregnancy guide covers contact with a rash illness too, and says which rash needs 999 or A&E. If you cannot tell how urgent something is, asking is never a mistake.

The sooner inflammatory muscle disease is recognised and treated, the more strength and function can be kept. If weakness is creeping into everyday movements, climbing the stairs and getting up from a chair in particular, it is time to arrange a specialist review.

How is myositis diagnosed?

By weighing several findings together rather than relying on one test. Dr Borukhson goes through your symptoms and tests the strength of your muscles, then arranges blood tests for muscle enzymes and for the particular antibodies linked to myositis, with scans or muscle studies when they are needed. Point-of-care ultrasound is part of the consultation with Dr Borukhson, so if the joints are affected as well it can help to tell whether they are inflamed, which means a good deal of the assessment is done in a single visit.

What does treatment for myositis involve, and for how long?

Treatment has two purposes: settling the inflammation the immune system is driving, and protecting your strength, and restoring it where that is possible. A corticosteroid, usually prednisolone, is often the first step towards getting the condition under control, and a steroid-sparing immunosuppressant such as methotrexate, azathioprine or mycophenolate is added so that, over time, the steroid dose can come down. Physiotherapy helps strength return. Expect a plan that usually runs for the longer term rather than a short course, with regular reviews and adjustments as you respond.

Will my strength come back?

For many people, yes: once the inflammation is under control, useful strength returns, and treatment started early gives the best chance of protecting the muscle and what you can do with it. Expect strength to return by degrees rather than overnight, with physiotherapy playing an important part in rebuilding it safely. How far and how fast varies between people, so the plan is revisited as you go. The monitoring appointments, and a word to the team when something changes, keep the plan where it should be.

Do the medicines have side effects, and what checks go with them?

The medicines are effective, and each comes with its own monitoring. A longer course of steroids brings a need for bone protection and monitoring; immunosuppressants call for regular blood tests and can make infection more likely, so a new fever, or feeling unwell, needs an assessment the same day, from your GP, your rheumatology team or NHS 111, and with the signs of sepsis in the first list under When to seek help it is a 999 or A&E emergency. That monitoring exists so the treatments can be used safely. Nothing is started until the specialist has gone through it with you, and all of it is supervised.

Does myositis ever involve the heart?

Yes, in some people. Because the heart is a muscle, the process that weakens the arms and legs can reach it too, either the heart muscle (myocarditis) or its rhythm. That inflammation can weaken the heart in some people, so a blackout, palpitations that are going on now and do not stop, or that bring chest pain, breathlessness, faintness or a faint with them, breathlessness severe enough that you are gasping or choking, or too breathless to say a word, or chest pain that is crushing, tight or like a pressure, that spreads to an arm, the jaw, the neck, the stomach or the back, that comes with breathlessness, sweating, feeling sick or feeling light-headed, or that came on suddenly and does not go away, is a 999 or A&E emergency, as the first list under When to seek help says; short of those, new chest pain, new or worsening breathlessness or palpitations, or tiredness that feels far out of proportion to your muscle symptoms, need an assessment the same day, from your GP, your rheumatology team or NHS 111, rather than being put down to the myositis (in pregnancy, breathlessness that comes on suddenly, or when you lie down, or with dizziness, is for your midwife or maternity unit straight away). Your care also includes checks on the heart, with blood markers, a heart tracing (ECG) and an echocardiogram, and a cardiologist shares the care if the heart needs attention; because the heart can be affected in any phase, remission included, it is looked at whether or not the muscles are active.

When should muscle weakness be looked at by a specialist?

Weakness in the big muscles that interferes with everyday movements, such as climbing stairs, standing up from a chair or lifting your arms above your head, is worth a prompt review by your GP or a rheumatologist rather than a routine one, especially when it has crept up over weeks rather than following one hard day's effort. Skin changes appearing alongside the weakness make that review more pressing; difficulty breathing or swallowing, or weakness that is getting worse fast, needs help the same day, from your GP, your rheumatology team or NHS 111 (in pregnancy, breathlessness that comes on suddenly, or when you lie down, or with dizziness, is for your midwife or maternity unit straight away), and choking that will not clear, breathing that is failing, or breathlessness so bad that you gasp, choke or cannot talk, is a 999 or A&E emergency, as the first list under When to seek help says. Weakness that arrives suddenly on one side of the body, with or without a drooping face or trouble speaking, is a 999 or A&E emergency as well, since it can be a stroke, even if it stops after a short time. Call 999 and do not drive yourself to A&E. The earlier myositis is recognised and treated, the better strength and function are protected.