There are many misconceptions in rheumatology - things that patients (and sometimes doctors) do not understand or may get wrong. If you have a question that you think should be included here, then email the webmaster
The hip joint is actually deep in the groin. Pain from the joint is felt there.
If pain is felt over the surface at the "hip" (just above the orange arrow) then the pain is coming either from the fluid sac over the bony point - the trochanteric bursa - or from the big muscle attachment there - the gluteal enthesis. Both may respond to a steroid injection. A hip X-ray will usually be quite normal.
Acute gout is caused by crystals of uric acid forming suddenly in a joint; the white blood cells come rushing in to sweep them away and in so doing release large quantities of inflammatory chemicals.
There are however many other causes of sudden joint pain and swelling. Diagnosing gout with complete certainty requires the finding of the crystals in a joint. There may be pointers to the diagnosis; thus, if the sufferer is a middle-aged man who is overweight and drinks a lot of beer (which contains yeasts that get broken down in the body to produce uric acid) then things look suspicious. Likewise the severity of the pain may be a clue. If a patient cannot bear the bedclothes on a joint it may well be gout. However, young ladies almost never suffer from gout (older ladies on water pills - diuretics - may do, but the pattern is different) and so an acute joint in such a person is almost never due to gout. There is a form of arthritis called Palindromic Rheumatism which flits about, and is often confused with gout, but requires quite different treatment.
Can you tell whether someone has gout from the uric acid level in the blood? No. You can have gout with a normal or even low blood uric acid, and you can have a high uric acid and not have gout. The only way to make a cast-iron diagnosis is to get fluid from the joint and find uric acid crystals in it.
At Queen Mary's we have learned from experience that the only way to deal with an acutely painful joint is to try and see it when it's bad. So, if you are a patient of the department you may be given a clinic timetable. If you phone, we will try and see you within 24 hours. If we can't, or your own doctor cannot see you, the next best thing is to get out the digital camara and take a photo (not too close or it will be blurred!). The same useful trick applies to any rash you might develop.
Polymyalgia rheumatica (PMR) usually presents as a fairly sudden onset of aching and stiffness in the shoulder and/or hip girdle, worse at night and with early morning stiffness. Suspicion is heightened if the ESR is elevated.
Steroids should be started promptly. 20mg daily is sufficient. If the problem is inflammatory then the symptoms should switch off within a week; see the patient again to check. A useful axiom is:
If the diagnosis has not responded to the treatment, reconsider the diagnosis because it's probably wrong.
So basically if there is no response at all then it isn't PMR.
Some patients may actually have rheumatoid arthritis, which can present in a polymyalgic way. These patients may respond initially, but tend to relapse before the steroids have been reduced very far. Or they might have polymyositis. So it's always worth checking the creatine kinase and if the ESR does not subside rapidly to normal, again think about alternative diagnoses. That said, some patients with what appears to be classical PMR run a relatively normal ESR.
Different rheumatologists have different regimes for steroid reduction in PMR, but a useful principle is that it should not be done too quickly or the patient will relapse. If you start at 20mg of prednisolone daily, and all goes well, a reduction to 15 in 1 month, 12.5 in another and 10 in a third is reasonable. Thereafter drop more slowly (so to 10/7.5 alternate days for 2 months, then 7.5 for another two, and so on. This will mean the steroids run out at about two years, which is the normal time course for PMR. However, if the patient does become symptomatic again, put the dose back up to the last dose . There is no need to jump back up to 20mg or higher. Remember also that patients on steroids for longer than 2 months should have calcium and Vitamin D3 cover as a minimum. Also you need to be absolutely sure that the relapse is really a relapse and not something else. We have see a patient whose relapses were actually new osteoporotic crush fractures in the thoracic spine, for which the steroid hikes were positively harmful.
About 10% of patients do not get off steroids and rheumatologists are nowadays introducing methotrexate in such cases.
Many patients have decided (often from drug information leaflets) that steroids are very bad and have dreadful side-effects. They need to have explained to them the concepts of relative risk, and risk-benefit analysis. What is a risk, and what is a hazard? A useful analogy is that risk means crossing the local high street on foot, while hazard is crossing the M25. In PMR the risk of not taking steroids is the possibility that the patient may develop giant-cell arteritis and suddenly lose the sight of one or both eyes. Faced with that possibility many patients will take the tablets! Suddenly the option of not taking them is perceived as a hazard.
Prabably not. Pain going down the leg from the back is common, and there are two main patterns. Referred pain is generated by the structures in the back itslef, which if you like are not very good at telling the brain where they are, so the brain hears messages from a wider area. This has been proved by putting tiny needles into the little joints at the back of the spine and passing an electric current through them. The pain generated is felt in the back, buttock and thigh and may extend below the knee.
Referred pain is dull and not usually easy to localise. On the other hand root pain, caused by compression or irritation of one of the large nerve trunks that go to make up the sciatic nerve, as well defined, severe, often has an electric shock like nature and is often associated with pins and needles or numbness. It is usually worse on bending, coughing or sneezing.
If you have this, then you have sciatica (irritation of the sciatic nerve).
Seropositive and seronegative: what do they mean?
Many patients get confused by these names not helped when temporary secretaries type zero-positive by mistake. The terms refer to the presence or absence of an antibody in the serum (the liquid part of the blood). The antibody is called Rheumatoid Factor.
In fact, to make things even more confusing, there are several different rheumatoid factors, but the one measured in the standard test is an antibody of the heaviest type of immunoglobulin which is known as IgM. This reacts against another class of immunoglobulin, IgG and forms what are known as immune complexes aggregates of antibody which attract attention from white blood cells called macrophages that eat things that look foreign. In doing this they release chemicals called cytokines which cause the inflammation characteristic of rheumatoid arthritis.
Rheumatoid Factor can be measured in different ways. The old-fashioned way was to dilute the serum over and over and see if it made sheep blood cells or little rubber particles stick together hence the sheep cell and latex agglutination tests. Each dilution halved the serum strength so 1 in 2, then 4, 8, 16, 32 and so on. On this system the higher the dilution as which the test is positive, the more of the antibody is present. 1:16 or greater is significant. This causes even more confusion if you get told the test is positive, but it is less than this, i.e. 1:2, 4 or 8. The level is known as the titre. Before deciding the test means anything, you need to know what the titre is. A low level occurs more commonly as you age. The more modern test produces a number. The higher this is, the more significant the test, and there is usually a lower cut-off number below which the test is considered negative. This varies between labs but is given with the result.
So if your test is positive, your arthritis is sero-positive, and if not it is sero-negative.
 |
|
Does it matter? Did I not get told, you say, that I have sero-negative rheumatoid arthritis, but how can that be? The answer comes back to where we started; there is more than one class of rheumatoid factor (IgG and IgA are the commonest other than IgM) but we only measure IgM. There is some relevance in this, as people with a significant level of IgM rheumatoid factor appear to develop more joint damage in the long term that those without. So early treatment is all the more important.
Other types of joint inflammation, for example arthritis associated with psoriasis or inflammatory bowel disease, are also sero-negative.
Does a positive rheumatoid factor mean you must have rheumatoid arthritis? Only if you actually have arthritis. It is not yet clear whether a high rheumatoid factor means you will necessarily develop RA if you don't have it yet. There is another blood test that may help clarify this, the cyclic citrullinated peptide antibody (CCP) but this is not universally available yet.
All clear now?
There is a widespread misconception that an MRI scan will provide the answer to why you have your back pain, arthritis and so on. It does not always do so. MRI (for Magnetic Resonance Imaging) is an imaging technique that shows soft tissues as well as bones, so it provides more information than an X-ray. Very simply, the molecules in a structure can be rotated by a strong magnetic field. When the magnet switches off, the molecules revert to their original position and in so doing give off a tiny electrical impulse that can be detected. Different molecules revert at different speed. Thus it is possible to distinguish between fat and water, and MRI relies on this to produce the image you see. It is an image that represents the structure of the tissues.
In fact, bone is not seen terribly well on MRI. You can see abnormalities within bone, for example if there is joint inflammation and the bone water content increases as a reaction to this. You can also see where bone has been replaced by something else, such as cancerous cells. But for many things a plain X-ray may be more helpful.
Isotope scans are quite different. Bone building cells (osteoblasts) will take up certain chemicals and so, if these are injected into the bloodstream labelled with a radioactive marker such as Technetium 99m, the label will follow the chemical to which is is attached into the cells. It can then be seen by a gamma camera, which is rather like a very special Geiger counter. The image looks like an outline of the skeleton with black blobs where the osteoblasts are very active. Thus isotope scans show the function of the bones rather than their structure. Activity may represent arthritis (a special scan called a SPECT scan is often used to look for this in the little facet joints in the back), abnormal bone metabolism or its replacement by something else.
It may well be that your doctor or specialist will need one or other of these scans but not necessarily so. In particular MRI scans of the neck and back are really only useful if there are signs and symptoms of a trapped nerve, with pain, pins and needles and numbness down a limb.
A shoe should protect your foot, yet allow it to walk normally (which the above shoe will not!). Many patients struggle to get shoes that fit, and hate the styles provided by the Appliance Department. A patient has given us a local tip - try Wide Shoes, 19 Bellegrove Road, Welling, Kent, DA16 3PA. They do a good selection of extra wide fittings.