Ankylosing spondylitis

Ankylosing spondylitis


Ankylosing spondylitis (AS) predominantly affects the spine and may lead to severe stiffness of the back. This booklet aims to tell you something about the complaint and how it may affect your health and activity. It also deals with how to look after yourself, different forms of treatment, and gives advice about posture, exercises, occupation and inheritance.

What happens

Spondylitis means inflammation in the joints of the spine, and comes from the Greek word for vertebra (spondylos). As the inflammation goes and healing takes place, bone grows out from both sides of the vertebrae and may join the two together; the stiffening this causes is called ankylosis.

The cause is not yet known. Occasionally more than one member of a family may get it as there is a hereditary factor (see ‘Some questions answered’). AS is neither infectious nor contagious, nor can it be caused by athletic activity or injury.

However, symptoms sometimes follow unusual exertion or strain, which may be blamed at first. Typically, it attacks young men but it can occur in women as well.

The backbone

The backbone, or spine, is made up of 24 bones (vertebrae) and 110 joints. The three main sections, cervical, thoracic and lumbar, differ in their shape and curve. The cervical (neck) section is the most mobile. In the thoracic (chest) section each vertebra has a rib attached by joints on each side. Below the lumbar section is the sacrum which sits like a keystone in the ring of bone which forms the pelvis. AS usually starts at the sacroiliac joints which lie between the sacrum and the pelvis.

Not just backache

Back troubles are some of the most common complaints seen in a GP’s surgery. Most people with back pain don’t have AS and the doctor must recognise the possible different nature of backache in each patient.

The most common cause of backache is ‘back strain’, which can happen at any age. A ‘slipped disc’ is another example. In older patients degenerative or wear-and-tear problems often affect the back. Diagnosis is made by listening to your symptoms and examining you. Your doctor may do certain blood tests and arrange for an x-ray. We will discuss these points separately.

The effects (early signs)

At the start AS usually causes low backache and stiffness and may be diagnosed as lumbago. You may feel pain in the buttocks, possibly down the back of your thighs and in the lower part of your back. You may have first noticed these symptoms after some exertion or strain. Aches and pains in the neck, shoulders and hips, or in the thigh (like sciatica), may follow.

In a few cases, and especially in children, the first complaint may not be in the back at all, but in the hip or knee, or in the leg – perhaps just a swollen knee.

In the beginning, in spite of these complaints, even careful examination by a doctor may reveal nothing.

Some people experience nothing more than a series of mild aches and pains coming and going over a period of months, never troubling them greatly. Others pass through a phase of active AS when symptoms are more troublesome; they become generally unwell, lose weight and tire easily. Gradually the ailment settles down and the worst pains disappear.

When AS has been present for several months the back may stiffen, usually lower down; and in some patients the disease then dies out, causing no further trouble. The stiff back is often painless and does not interfere with physical activity, because the upper part of the spine, the neck, hips and limbs can remain quite normal. If you feel stiff in the early morning this is a sign of inflammation and perhaps it may be an hour or so before you have properly limbered up – it may indicate the need for anti-inflammatory drugs.

In its early stages AS causes considerable pain, but effective treatment is available to relieve this, even though the discomfort is not always banished. In some people the disease becomes much less active, or even ceases completely. In others the disease continues to be active, causing pain and stiffness. At first you will most probably be able to carry on with your work and lead a normal life. Later you may find it difficult to continue in the same job. (See ‘Employment’.)

Limb joints

Sometimes, either earlier or later, AS may affect joints other than the spine. The hips, knees, ankles and shoulders may be involved. The smaller joints of the hands and feet can be attacked, but usually only in a few places. You may experience a period of aching in the joints in question, perhaps with some swelling. As a result some of them may not move fully, but with treatment and active exercises from the start the disability should remain slight. In particular, your hip must not be allowed to stiffen in a bent position as this can lead to damage in the knees, and cause more backache.

Other trouble spots

Tender places may sometimes develop in bones that are not part of the spine – the heel bone for example. When this is affected it becomes uncomfortable to stand on a hard floor. The bone of your ‘seat’ (ischium) can be involved and make sitting on chairs uncomfortable.

Some patients experience chest pain. This does not come from the heart, but from the joints between the ribs and the breastbone. You may notice a strapped-in feeling as the ribs become less easy to move. However, your lungs are working well because the diaphragm is not affected. Breathing exercises (see ‘Daily exercise programme’) will help you maintain ribcage mobility.

Iritis (inflammation of the iris which forms the pupil) occasionally occurs, so if you suddenly develop a red eye go to your doctor immediately.

Other rare complications, affecting less than 1 patient in 100, may occur. These include the heart, lung and nervous system, but treatment is available for all of them. Patients with AS are not any more at risk from getting heart attacks, strokes or cancer than the general population. Colitis, or inflammation of the bowel, is associated with AS in some people, as is a skin condition called psoriasis (see arc booklet ‘Psoriatic Arthritis’).


AS is often not diagnosed until a patient has had backache for 2 or 3 years or even longer. A blood test for inflammation may show an abnormal result in the early stages and so help your doctor to distinguish it from more common forms of backache. There are three commonly used blood tests for inflammation: the CRP (C-reactive protein), the ESR (erythrocyte sedimentation rate) and the PV (plasma viscosity). Your doctor may request one or more of these. X-rays may also confirm the diagnosis. However, in the early stages x-rays may be normal, even when the symptoms are severe.

A special test (HLA-B27 antigen) can be used. This is like testing for a blood group but concerns the white and not the red blood cells. If it is positive it shows that you have a tendency to AS, but does not prove the diagnosis (see ‘The family’).

Associated problems

It is now clear that AS is one of a group of diseases (‘spondarthritides’). Other examples are psoriatic arthritis, colitic arthritis and reactive arthritis. Each of these can occur with AS or even before it. Some children can develop arthritis which later develops into AS. In some cases reactive arthritis, which may be associated with an infection of the bowel or the urethra (the tube from the urinary bladder), can develop into AS. The link between these and other diseases has revealed some of the genetic factors that are involved. Having certain genes will predispose you to AS, but without one of the ‘triggers’ the disease will not appear.

The outlook

AS takes a different course in different people, and no two cases are exactly the same. The symptoms may come and go over long periods, and it may never settle down. Your lower back will probably become stiff, but the same can happen to the upper part of your back and neck as well. Therefore it is most important to maintain a good posture.

Not every person suffering from AS will return to normal, even when the exercises are followed, but serious deformities can usually be prevented. Sufferers with a bent back can often be acutely self-conscious and concerned about how others see them. But even though this may be difficult most patients can come to terms with the problem.

Severe involvement of hip or knee may need surgical treatment such as a new hip or knee joint.

Summing up ankylosing spondylitis

It is a form of inflammation which affects the spine, usually beginning lower down.

After a period of inflammation which causes aching and stiffness in the back it may settle down, but may also persist for many years.

It may leave some pain and stiffness in the spine. It may interfere with your work and physical activity.


Do your best to keep fit. Eat anything, especially protein such as meat and fish, but don’t get overweight. Take plenty of exercise. The motto for treatment which all patients should remember is: it is the doctor’s job to relieve pain, and the patient’s job to keep exercising and maintain a good posture.


If the AS is very active and the stiffness very troublesome, a spell off work or in hospital may be necessary. This does not mean keeping still in bed, because this can hasten the stiffening of the spine. So even a spell of rest from work means that you will be encouraged to do exercises for your back, chest and limbs to keep them supple.

When you are in bed it is important that you should lie quite flat on your back. Some of the time you should practise lying on your front. ‘Prone lying’, as this is called, is best done for 20 minutes before rising in the mornings and 20 minutes before going to bed at night.

At first you may not be able to tolerate more than 5 minutes at a time, or may even need a pillow under your chest. But with practice, as the spine relaxes, it will become easier. If you make a habit of this it will help prevent your back and hips becoming bent. It may, of course, not be practical every day but it is better to devote some time to it than nothing at all.

Your bed

Your bed should be firm. If you have an internally-sprung mattress, get a suitable board put between the mattress and the bed frame. A sheet of plywood 70 x 150 x 1 cm is ideal. A hardboard door panel is satisfactory but not so durable. You will find this more comfortable to lie on than a bed which is too yielding. Even when the painful active phase of AS has passed, it is important to keep a firm bed in order to prevent any tendency for spinal curvature.

Medical approach

There is no cure at present for AS. The doctor aims to relieve the symptoms, to improve spinal mobility where this has been lost, and to allow you to maintain a normal job and social life.

Although AS will tend to become less active as you get older, treatment must continue. In particular you must pay close attention to good posture, mobility and exercise.

Although the disease cannot be cured, much can be done to help. The doctor will prescribe tablets that relieve pain (analgesic) and inflammation. There are several drugs which will reduce or kill the pain, and give you a good night’s sleep and sufficient freedom from pain to do exercises.

You will probably need tablets during bad patches and some people need a small maintenance dose of their drug over a longer period. Some tablets are manufactured to remain effective throughout a 24-hour period, thus helping relieve night pain and morning stiffness.

Some drugs are called ‘disease-modifying’: they never make an immediate impact on the disease but rather take some time to start working, but ultimately they may make a big difference to the disease. Sulphasalazine and methotrexate are two such drugs. Both these drugs, commonly used in other forms of arthritis, are more likely to benefit the arthritis in the limb joints rather than the arthritis in the spine.

Some of the newer drugs are given by injection. These fall broadly into two groups:

  • Bisphosphonates are given in short bursts over a period of a few weeks – an example is the drug called pamidronate. You may feel pain relief in the spine soon after receiving this drug.
  • Biological therapies are drugs which are also given by injection – either as an infusion over a few hours or as a twice-weekly injection. You may also feel early benefit with these drugs. Examples are infliximab and etanercept.

Heat in its various forms will help to relieve pain and stiffness. A hot bath before going to bed, a hot-water bottle or electric blanket may be quite enough.

Surgery has only a small place in treatment. An operation is used to help restore movement to damaged hip joints (arthroplasty) and, rarely, to straighten the back or neck of someone who has become so bent they cannot look forward (and find it dangerous just to cross the road).


Since untreated AS causes increased bending of the spine (the person becomes progressively more stooped), you must keep as straight and erect as possible. Hardback, upright chairs or straight-back rocking chairs are far better for your back posture than low, soft, upholstered chairs.

Pay special attention to the position of your back when at work, so that you do not have to stoop. If you sit at a desk or bench, see that your seat is at the proper height and do not sit in one position for too long without moving your back.

A job which allows sitting, standing and walking is ideal. The most unsuitable type of work is that in which you have to stoop over a bench for hours at a time. If you have a heavy or tiring job do not tackle other activities at home or elsewhere until you have had a break. If necessary, rest flat for a time. It may also help if you can rest flat for 20 minutes at midday. At such times try to lie for part of the time face downwards.

If your job involves a lot of stooping or back strain, talk this over with your doctor. S/he, or a doctor from the hospital or from the Employment Medical Advisory Service or Disability Services Team, may be able to advise you on how you may change to more suitable work. Some people with AS have found it helpful to show this booklet to their employers or their doctors in explaining their needs.

Corsets and braces are hardly ever helpful, and indeed can make AS worse. It is better to develop your own muscles, and keep a straight back by natural means. Very occasionally some form of support may be necessary, for example after a back injury. However, this decision should only be taken by a doctor who is experienced in treating people with AS.

The family

In the UK, and in most populations of European origin, AS is virtually confined to those who inherit the white cell group HLA-B27. This group also occurs in 7–10% of the healthy population. Nearly all people with AS will have this particular blood group.

However, it is very important to note that there are far more people with this blood group who never get AS than those who do. Even in families where one member suffers, a brother or sister can share the same blood group and never get the disease.

Parents with AS sometimes ask if their children should have the HLA-B27 test – to see whether they may develop the disease in the future. The answer at present is ‘no’; there is no way of knowing which child with this blood group is likely to get the disease and it would only cause unnecessary worry.

Sex and pregnancy

AS usually starts in the most sexually active period of one’s life. The disease can make the person with AS feel tired, which may reduce the desire for sex. This may put a strain on a loving relationship which can also be aggravated by lack of understanding by the partner. You may experience pain during sexual intercourse because of inflammation in the sacroiliac joints and lumbar spine. Lack of mobility of the hips, especially in women, would also cause difficulty. People can be helped in various ways. The inflammatory pain can be suppressed with drugs. Poorly mobile hips can be treated with an artificial hip joint. And if surgery is not appropriate there are alternative positions for sexual intercourse (see arc booklet ‘Sexuality and Arthritis’). There may be a need for sexual counselling for both partners; organisations such as Relate can be very helpful in this respect.

Pregnancy in women with AS provides no special problem for mother or baby. However, in contrast with some other forms of arthritis the condition does not die down during pregnancy. The babies are usually born by the normal route, but occasionally a Caesarean operation is necessary if the hip joints become stiff.

Although tablets commonly used for treating AS have never been shown to damage the unborn baby (foetus), it is sensible to take as few as possible – especially during the first 3 months of pregnancy (see arc booklet ‘Pregnancy and Arthritis’).


People with AS are capable of doing a wide variety of jobs, from strictly sedentary to manual (e.g. carpenters and builders). Many have pursued very successful professional and business careers.

AS is not a sentence to life-long unemployment.

Should I give up work?

People who work – both in physical jobs and in offices – will have difficulties if they develop arthritis, but the problem may not be as serious as it first appears. Difficulties with work are recognised by the Department for Work and Pensions. Work assessment and retraining can be arranged by your local Disability Services Team, who can be contacted through a Jobcentre or Jobcentre Plus office. If you are disabled due to arthritis and wish to carry on working then the local Employment Medical Advisory Service can also help keep you in work by providing equipment which is needed to make it easier for you to do your job. Advice on how to contact these agencies can be given by a health professional such as an occupational therapist or at a Citizens Advice Bureau.


If you have to make a long car journey, stop from time to time for 5 minutes and get out of the car for a stretch as pain and stiffness can distract your attention.

Many people with stiffness of the neck and other parts of the spine have difficulty in reversing into parking spaces or a garage; special mirrors can be fitted to your car to help you. If this is the case, it is worth practising the reversing technique using the new mirrors in an open area with some light wooden obstacles (such as a broom handle stuck in the earth) to act as markers.

The stiff neck of a person with AS is more easily hurt than normal, so head supports are advised to avoid sudden injuries to the neck. A disabled driver’s Blue Badge may be used if you can’t walk very far, but these are strictly regulated (see arc booklet ‘Driving and Arthritis’).

Sport and exercise

Exercise is good for AS, so you should keep active. Swimming is the best form of sport as it uses all muscles and joints without jarring them. And regular swimming is something the whole family can join in with.

Regular daily exercise is important. It is best to choose activities you enjoy doing for their own sake. For those who prefer to carry out an exercise routine some suggestions are listed below (see ‘Daily exercise programme’). It is wise to do at least some each day. Contact sports (such as rugby or basketball) are best avoided as the joints and spine can be injured.

General advice

Lie on your front on a firm surface for about
20 minutes every morning or evening.

Repeat your deep-breathing exercises at frequent intervals during the day.

Be aware of your posture – correct it constantly, not only during your exercise periods but also during the day while standing, sitting and walking.

Do some of your exercises every day

Some questions answered

How should I take my tablets?

Pain-relieving tablets are usually best taken during a meal or just before; they irritate the stomach lining less when mixed with food. This is not of vital importance, so don’t worry if you cannot.

Why do I feel tired?

Tiredness is sometimes due to the activity of the disease and this can be detected by a blood test for inflammation (see ‘Tests’). Occasionally anaemia causes tiredness, although some people remain anaemic for long periods and keep perfectly fit. Tiredness is sometimes due to frustration and depression rather than to the disease.

Would manipulation help the spine?

Unfortunately no. In fact manipulation of the spine, especially the neck, can be positively dangerous.

Would acupuncture help?

Acupuncture may relieve pain, but it does not affect the disease.

Does treatment in a pool help?

The advantage of exercise in water is that the buoyancy of water helps movement. There is no special benefit from brine or other types of baths. Some hospitals have a pool in the physiotherapy department but ordinary public swimming pools are usually just as good for people with AS. Breaststroke may be a problem if there is limited neck movement, particularly extension.

Can I do anything to stop stiffness in the morning?

Some find a hot bath helps; others prefer doing exercises. Anti-inflammatory tablets that work overnight also help.

Will I have any trouble in taking out a life-insurance policy?

Life-insurance companies often do not understand this disease, so they may want to load the premium. But it may be possible to get normal terms. The National Ankylosing Spondylitis Society (NASS) has, over the years, helped members and it now has a list of companies who are more sympathetic to people with AS. You should shop around if a loading factor is included and, if that fails, contact NASS.

Is it all right to be on the birth control pill?

Yes, but always mention this to your doctor.

What is the chance that my children will get AS?

The chance of your children developing it is small, not more than 1 in 50, compared with 49 out of 50 chances of producing a normal, healthy child. No doctor would discourage a person with AS from having a family.

Is any research going on to try and find the cause of AS?

Yes, in many centres around the world, but it costs money and arc is supporting numerous projects. Studies following on from the discovery of HLA-B27 have proved very revealing with regard to the influence of inheritance and infection.

Some case histories

AS is a very variable disease; indeed two people with it are hardly ever alike. The typical course described in this booklet does not occur in every person, and for this reason a few case histories are described below. They are reproduced by courtesy of the National Ankylosing Spondylitis Society.

Arthur, 24 years old, whose disease started in childhood

At the age of 11 Arthur developed a swollen right knee which did not respond to aspirin treatment. He was seen at his local hospital and the leg was put into a plaster-of-Paris splint for 6 weeks. The knee was very stiff after this but the swelling had settled. After 3 months of physiotherapy the knee had returned to normal. A similar episode occurred when he was 14 years old and once again the knee settled.

At the age of 21 he began to experience pain in the buttocks and the top of his legs, which was thought to be lumbago. He found that aspirin had no effect on the pain, which would wake him at night. He was so stiff in the mornings that he had to wake himself an hour earlier to loosen up so he could get to work on time.

Arthur decided to see an osteopath, who manipulated his spine on three occasions. The pain seemed to be worse after the manipulations for 2 or 3 days, so he stopped going.

At the age of 24 he was referred to the hospital, where a diagnosis of AS was made. At the time of his referral he had been getting bouts of low-back pain waking him at night for about 4 months. He was demoralised and had changed his job from working in a warehouse doing heavy lifting to clerical tasks. The change had not helped his back. He responded well to appropriate drug treatment and physiotherapy. The nature of his disease was explained to him and he felt much less depressed about it.

Comment: Arthur’s disease began in childhood but it was not possible to make a firm diagnosis of AS at that stage. Osteopathic manipulation made his symptoms worse, whereas controlled exercise as instructed in the physiotherapy department proved to be useful.

Dennis, 48 years old, whose disease did not go into remission

Dennis first noticed low-back pain while he was in the Army at the age of 21. He would wake with severe pain and stiffness at 5.00 am. His disease was not recognised at that time and it was felt that he was trying to get out of the Army on medical grounds.

While on leave his parents took him to see an orthopaedic surgeon, who found that he had an elevated ESR (a blood test for inflammation). The diagnosis of AS was suspected at that time, although his x-rays did not show any abnormality. He was discharged from the Army and got a job as a salesman.

The back pain persisted although painkillers did dull the discomfort. He never seemed to get periods of relief from the pain. Gradually the pain caused Dennis to adopt a stooped posture which has never improved in spite of exercises. He did find that when indomethacin became available the pain was much easier to tolerate and his stoop never worsened from then on.

Comment: For Dennis his AS has not gone into remission. This occurs in some patients.

Susan, 31 years old, whose disease was reactivated after an injury

Susan developed AS at the age of 19, but after 3 years she was free of symptoms. At the age of 31 she was shaken up in a car accident, no bones were broken but she was bruised around the face, chest and thighs.

Two days after the accident she developed acute pain in the thoracic spine, which was worse on breathing.

Susan had to be given large doses of painkilling drugs to settle the pain. The AS became reactivated in the thoracic spine and took 4 months to settle. Her chest expansion, which had previously been normal, was reduced to less than half.

Edith, 73 years old, with advanced AS and no history of backache

Edith was knocked over by a passing car while she was crossing the road. In the casualty department of the local hospital she was found to have fractured her lumbar spine, which was rigid from AS. Edith denies having any back pain during her life.

Comment: This is uncommon but does illustrate the fact that x-rays may look impressive, but the symptoms don’t always match them. The reverse is also true: someone suffering a great deal of pain may have x-rays which show nothing. It has been suggested that it is more common for AS to run a less painful course in women than in men, but this is not always the case. It has also been shown that on the whole men get their AS diagnosed much earlier than women.

Last word

Do not be afraid of AS. It will help to take a positive attitude. There is a lot that a person with AS can do for themselves to help relieve symptoms and prevent deformity.

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