Tests and terminology in psoriatic arthritis

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ACUTE PHASE PROTEIN - a protein produced in the liver which increases during inflammation, e.g., C-reactive protein (CRP) see under C.
ALBUMIN - a blood protein which falls in severe inflammation, malnutrition and some kinds of kidney disease.
ALKALINE PHOSPHATASE - liver enzyme monitored in patients taking methotrexate or azathioprine
ARTHRALGIA - pain in a joint.
ARTHROPATHY - something wrong with a joint.
ARTHRITIS - inflammation of a joint.
AST - a liver enzyme - see alkaline phosphatase above


BAKER'S CYST - swelling behind the knee which contains fluid, common in osteoarthritis, also rheumatoid arthritis, and sometimes psoriatic arthritis.


CITRULLIN ANTIBODIES - new and very specific test for rheumatoid arthritis.
CREATININE CLEARANCE TEST - test done on a 24-hour urine sample + a blood sample as a measure of kidney function.
C-REACTIVE PROTEIN (CRP) - a protein produced in the liver which rises in quantity in the blood when there is active Inflammation. In psoriatic arthritis pain may be present with some swelling in a number of small joints without this showing an abnormal result. Increased -when there is active involvement of large joints or widespread bone erosion


DEXA SCAN - this is the best measurement of bone mineral density. Inflammatory spondylitis found in some patients with arthropathy may be accompanied by reduced bone density in the vertebrae particularly.
VITAMIN D - special forms of this can be measured in blood and if low supplements of vitamin D3 maybe advised.
DNA - antibodies to DNA are the most specific and reliable test for the diagnosis of systemic lupus erythematosus and are rarely found in psoriatic arthropathy whereas the screening test for anti-nuclear antibodies is occasionally found positive but usually has no significance.


EFFUSION - collection of fluid in a joint.
ENA - antibodies to extractable nuclear antigens are looked for in patients with connective tissue diseases such as systemic lupus erythematosus and are helpful in predicting which organs are likely to be affected and indicating a more specific diagnostic category.
ENTHESIS - the junction between bone and ligament or bone and muscle.
ENTHESITIS - inflammation of this junction is commonly found in psoriatic arthritis.
ESR - traditional test for inflammation - not specific for arthritis and may be normal despite it.


FACET JOINTS - the small joints extending throughout the spine which slide up and down in movement and a source of pain when inflamed.
FOLIC ACID - given to patients on methotrexate, reduces likelihood of mouth ulcers and blood count abnormalities.


GAMMA GT - blood test for a protein made in the liver, particularly sensitive to alcohol overuse, but found in other causes of liver dysfunction. Patients with high results are not safe to take methotrexate without careful evaluation.
GLUCOSE - the sugar found in the blood which the brain and the muscles use as fuel. Too high in diabetes, too low in diabetics given too much insulin.
GLUCOSE TOLERANCE TEST - test involving taking a dose of glucose followed by a series of blood tests to see how much has appeared in the blood over a period of hours and used to confirm diagnosis of diabetes. Useful in patients on long-term steroid treatment.
GLYCATED HAEMOGLOBIN - test done on blood in diabetes to check on long term control.


HYDROCORTISONE - the least powerful of the steroid medicines available.
HYPOGLYCAEMIA - low blood sugar.
HYDROXYUREA - a drug used in the treatment of psoriasis.


INTRAVENOUS INFUSION - technique of giving medicine such as Infliximab/Remicade. IRON - important component of haemoglobin, the oxygen-carrying pigment which gives blood its colour. Hence iron may be given as a medicine in anaemia.


JOINT - site at which two bones come together, may be very mobile, eg, shoulder, or almost immobile, eg, the sacro-iliac joint.
JOINT FLUID - this has special features in psoriatic arthritis (see under L.)
JUNCTIONAL TISSUE - see enthesis above


KENALOG - proprietary name for triamcinolone acetonide, longest-acting and most potent steroid available for joint injections; at present.


LATEX TEST - very sensitive, but not very specific test for rheumatoid factor in the serum.
LEUCOCYTES - white blood cells increased during infection. In psoriatic joint effusions leucocytes, rather than lymphocytes, show a particular increase in numbers. In rheumatoid arthritis lymphocytes usually predominate. In the blood lymphocytes are often found to be reduced in patients on immunosuppressive forms of treatment.
LUNG FIBROSIS - a rare complication of treatment with methotrexate predominantly in elderly women.


MACROCYTES - red blood cells of increased size. May be found in patients treated with azathioprine, methotrexate or sulphasalazine.
MACROPHAGES - cells which devour the remains of dead cells of other kinds and sometimes bacteria also.
MRI - magnetic resonance imaging - uses magnetic fields and radio signals to compose images of body slice by slice without using x-rays.


NUMBNESS - loss of sensation in fingers, eg, in carpal tunnel syndrome, in toes in sciatica or generally in peripheral neuropathy and other neurological diseases. Seen occasionally as a drug side-effect.


ONYCHOLYSIS - a severe form of the psoriatic nail dystrophy in which there is thickening, splitting of the nail into layers and crumbling of the edge.


PITTING - mild form of nail dystrophy in which minute indentations usually smaller than the head of a pin are seen in the nails.
PLANTAR FASCIITIS - a cause of heel pain, a variant of enthesitis frequently found in psoriatic arthropathy.
POLYARTHRITIS - arthritis affecting many joints.


QUEEN TEST - quality question devised by a distinguished hospital architect and pioneer of operational research in hospitals. The question is: If we were doing this for the Queen, is this how we would do it.


RETINOIC ACID DERIVATIVES - drugs used in the treatment of psoriasis and helpful for the arthritis in some cases.


SPONDYLITIS - spinal inflammation may be part of psoriatic arthropathy.
STEROIDS - short form of the word corticosteroid, too high a dose used for too long may lead to diabetes, high blood pressure, poor wound healing, susceptibility to infection, cataracts and glaucoma. More recently, it has been appreciated that the long term use of quite small doses may lead to osteoporosis. Some psoriasis sufferers given oral steroids will find that, on cessation of treatment, the psoriasis appears in areas not previously affected.
SULPHASALAZINE - an old, but still useful drug for psoriatic arthritis but rarely helps the skin. Careful monitoring is essential in the early weeks of treatment particularly. Serious side-effects in the longer term are uncommon.
SYNOVITIS - inflammation of a joint.


TECHNETIUM - a man-made radio-active element used in isotope scans. THROMBOCYTOPAENIA - a reduced number of platelets in the blood. This may be a cause of bruising or bleeding and is a potential side-effect from a number of treatments, hence the need for regular blood monitoring.
TNF - tumour necrosis factor. A number of biological agents which block this rae*ator of inflammation have been devised, notably Embrel and Remicade. They are but the first in a series of agents based on similar principles which will have much to offer in the future.


ULTRASOUND - this is used both in diagnosis and treatment. High resolution ultrasound equipment has an increasing role in the diagnosis of rheumatic disorders and its value as a treatment tends currently to be underestimated in the UK.
UREA - blood urea is measured as a fairly guide to kidney function but is useful as part of a biochemical profile in monitoring drug treatment.
URIC ACID - if increased in blood may indicate gout.


VASCULAR - pertaining to blood vessels.
VASCULITIS- inflammation of blood vessels, a feature of some rheumatic diseases but not psoriatic arthritis.


WAX - hot wax baths were formerly very commonly employed for the treatment of stiff rheumatic hands and were actually quite effective in the short term. The technique was time-consuming needed to be repeated frequently and the apparatus was occasionally a fire hazard, so has largely been withdrawn.


X-RAYS - main disadvantage is the radiation risk. Other techniques of imaging employed are ultrasound or MRI scans, but x-rays are considered useful in specific situations.


YTTRIUM-90 - a radio-active element, sometimes used to inject into chronically inflamed joints to provide longer periods of relief than steroid injections and mostly used for knees. Results in psoriatic arthritis less good than in rheumatoid arthritis.


ZYLORIC - brand name for allopurinol, drug used in the treatment of gout. Quite frequently new patients give a history of receiving this treatment when they have shown their doctor a red, swollen, painful toe and the diagnosis of psoriatic arthritis has not been considered.

List compiled by Dr Anthony White Consultant Rheumatlogist.
Originally published as part of the Psoriatic Care Fact File
Published By PAPAA Publications ©2004