, Juraj Payer2 and Manfred Herold3
(1)
National Institute for Rheumatic Diseases, Piestany, Slovakia
(2)
Fifth Department of Internal Medicine, Comenius University University Hospital, Bratislava, Slovakia
(3)
Department of Internal Medicine VI, Medical University of Innsbruck, Innsbruck, Austria
Radiography The radiograph (X-ray) is still ‘a gold standard’ of musculoskeletal system examination even in the era of novel diagnostic imaging methods such as USS, CT and MRI. It enables evaluation and assessment of changes to the skeleton in arthritic and orthopaedic disorders, monitoring the potential progression of the disease over time and assessment of their changes with respect to treatment. Projectional radiography is commonly used in examining the joints and the spine and involves taking two X-rays, usually at right angles to each other, to produce 2D X-ray images. Image intensification may be used for targeted joint injections (e.g. hip joint or spinal injections) or in internal fixation of fractures. Radiographic examination with contrast medium is used in rheumatology for diagnosing oesophageal dysmotility in systemic sclerosis.
Radiographic examination after an intra-articular application of the contrast medium (arthrography) is utilised less in the era of CT, MRI and arthroscopy. Radiographic examination of the vascular system after intravenous injection of a contrast medium (classical angiography, digital subtraction angiography – DSA) is utilised, for example, in the diagnosis and assessment of vasculitis.
Radioimmunoassay An analytical method used to assess the concentration of soluble antigens or haptens. In this method, the antigen or hapten is labelled with a radioactive isotope which competitively inhibits the binding of unmarked antigen with specific antibody. The relation between the inhibition and concentration of the analysed antigen is assessed by a set of standard solutions of unmarked antigen of known concentration. It was the first method to enable quantification of various proteohormones, neuropeptides and other substances in complex biological fluids.
Radioimmunoelectrophoresis An electrophoretic analysis with radioactive labelled antigen or antibody to identify the precipitation line.
Radioimmunoscintigraphy Monoclonal antibodies directed against antigens associated with malignancies are used in this in vivo diagnostic method. After the conjugation of antibodies with radioactive nuclides and their administration to a patient affected by a malignancy, these conjugates bind exclusively to the malignant cells and identify them. Contemporary radioimmunoscintigraphy is a sensitive method able to identify a tumour weighing as low as 0.1–1.0 g, including possible metastases.
RANK (receptor activator of nuclear factor κ-B) A transmembrane protein consisting of 616 amino acids that is localised on precursors of osteoblasts. Binding OPG-L (RANKL) to ODAR (RANK) leads to the differentiation and activation of osteoblasts.
RANKL (receptor activator of nuclear factor κ-B ligand) Produced by osteoblasts. It belongs to the TNR receptor family. Initially, it was called osteoclast differentiation factor, which represents its main role in the body. It is produced by osteoblasts in soluble and membrane-binding forms. Binding to its receptor (RANK) on the surface of osteoclasts and their precursors leads to the activation of differentiation, maturation and production of new osteoclasts and stimulation of their osteolytic activity.
Rapamycin A relatively new immunosuppressive agent, originally developed as an antifungal agent, with a structure similar to tacrolimus but with a different mode of action. It inhibits the response to IL-2 and thereby blocks the proliferation of B and T lymphocytes, the synthesis of lymphokines and responsiveness of T cells. Its immunosuppressive concentrations are significantly lower than those of tacrolimus and cyclosporin.
Rapid assessment of disease activity in rheumatology (RADAR) – see Instruments of assessing (health status measurements, outcome measurement).
Raynaud’s phenomenon (RP) A symmetrical non-progressive vasospastic disorder affecting the fingers and toes, which manifests as paleness and/or cyanosis. Such a symptom is due to cold exposition or emotional stress. Maurice Raynaud (1834–1881, French physician) first described the phenomenon in 1862.
► Clinical symptoms
The typical clinical picture consists of three phases. In the first phase, the fingers become pale due to vasospasm of the digital arteries. In the second phase, dilatation of the capillaries and venules occurs, leading to cyanosis due to blood stasis and its subsequent deoxygenation. The patient usually complains of cold sensations and paraesthesia during these phases of RP. When heating the limb, vasospasm retreats and blood perfusion dramatically increases. This phase of reactive hyperaemia is characterised by a bright red colour of the fingers and is often associated with unpleasant pulsating sensations. The changes to the fingers extend from distal parts towards proximal areas and never proximal of the metacarpophalangeal joints. The fingers and toes are most often affected, particularly the second, third and fourth fingers of the hand, less frequently the toes. The acral part of the nose, the tongue and ear can be affected. Infrared thermography can be used in the detection and quantification of RP.
Reactive arthritis (ReA) Aseptic immunologically mediated joint inflammation, which develops in association with distant infection in the body. The disease has a systemic character and usually develops after upper airway infections and urogenital or gastrointestinal infections. However, ReA may develop after infection localised anywhere in the body, and often, the association between clinically and microbiologically defined previous infection and ReA may not be found.
Main features of ReA:
Arthritis, eventually other musculoskeletal symptoms (myalgia, tendinitis, osteitis, enthesopathy).
Skin and mucosal lesions.
Ophthalmic lesions (uveitis, conjunctivitis).
Organ lesions are rare (nephritis, carditis).
The prognosis is usually favourable with spontaneous remission.
Chronic course of the disease with functional impairment is rare.
Significant association with the HLA-B27 antigen.
Reactive arthritis, formerly referred to as Reiter’s syndrome This syndrome is characterised by three conditions, namely, reactive arthritis, conjunctivitis and urethritis. It is a subgroup of reactive arthritis which belongs to spondylarthritis. Arthritis is typically mono- or oligoarthritis in lower extremities, developing in young people who have overcome an infection. Patients may also experience other extra-articular manifestations of reactive arthritis, i.e. inflammatory back pain and skin (keratoderma blennorrhagicum, erythema nodosum) and mucous membrane manifestations. Most frequent pathogens are enteric infections (Salmonella, Shigella, Yersinia and Campylobacter), followed by Streptococcus, Chlamydia trachomatis, Neisseria, Ureaplasma urealyticum and Borrelia; 65–96 % of patients with reactive arthritis are HLA B 27 positive.
Reactive nitrogen intermediates (RNI) Nitric oxide, for which NO synthase is involved in its synthesis, is the main representative RNI. NO is involved in a number of protective, regulatory and also harmful reactions in the immune, nervous and cardiovascular systems. Other oxides of nitrogen, anions of peroxynitrous and nitrous acid and finally anions of nitric acid can originate from nitric oxide.
Reactive oxygen intermediates (ROIs) Unstable molecules that possess an uncoupled electron (free radicals) or excited state electrons (singleton oxygen). The basic free radical derived from molecular oxygen is superoxide from which hydrogen peroxide and subsequently hydroxyl radicals are formed. ROIs are formed in higher concentrations, particularly in professional phagocytes (neutrophils, macrophages), where they are involved in the destruction of phagocytosed microorganisms. They are also very effective cytolytic substances and may damage the cells and tissues of the hosting organism during immunopathological reactions.
Receptor A complex of atoms or molecules that form a site with stereochemically specific affinity for a particular substance known as ligand (agonist in pharmacology). The receptors are usually present on the surface of cells but may also be located on the inner part of the cytoplasmic membrane or in the cytoplasm. The binding of ligand (agonist) to the receptor is the signal for the cell to perform certain physiological (in some cases pathological) responses. The binding of an inhibitor (antagonist) to this receptor leads to the inhibition of the receptor’s function. Neurotransmitters, hormones, antigens, cytokines or other mediators transmit their signal through receptors, and thereby, information is transmitted between cells. One cell can transfer the information to another cell directly without the need for any chemical messenger. In such a case, the receptor of one cell reacts with the receptor (effector) of the other cell.
Receptor activator of nuclear factor κ-B – see RANK (receptor activator of nuclear factor κ-B).
Receptor activator of nuclear factor κ-B ligand – see RANKL (receptor activator of nuclear factor κ-B ligand).
Referred pain The pain felt in an area that is distinct from the affected area. It is common in lesions of visceral organs. It is usually felt in the area that is innervated from the same spinal segment as the involved viscus.
Reflex A basic functional unit of nervous system function. It can be defined as an involuntary, rapid and stereotype response to a peripheral stimulus.
Reflex sympathetic dystrophy – see Algodystrophic syndrome (ADS).
Reflexive massage The fundamental of this massage is the knowledge that functional connections exist between the skin and muscle areas, bones, vessels, nerves and subcutaneous tissue and inner organs, which are supplied from the same spinal segments. Reflexive massage can be used in both organic and functional disorders, particularly in the chronic stage. The main indications are spinal pain syndrome and extra-articular rheumatism.
Reflex arc The set of structures involved in reflex pathway. It consists of five components: receptor, afferent nerve pathway, integration centre, efferent nerve pathway and effector. The connection with the central nervous system runs through the integration centre.
Rehabilitation methods Rehabilitation methods in rheumatoid arthritis are focused on maintaining the scope of movement and muscle strength. The patient must be taught about the knowledge of how to protect affected joints by improving muscle power and how to improve their daily routine. The use of orthoses and various auxiliary instruments in performing daily routines is, apart from rehabilitation, one of the basic components of joint protection. The resources of physical therapy (PT) need to be used to minimise the symptoms and signs of RA, such as pain and atrophy, decrease in local metabolism, spasms etc. Balneotherapy, both local and systemic, is also important in the management of RA.
Relapsing polychondritis A very rare disease affecting a number of organs. The disease is episodic but occasionally progressive. It is an inflammatory process affecting structures of the cartilage and tissues with a high content of glycosaminoglycans. Clinical symptoms appear in the areas of pinna of the ear, nose, larynx, upper airways, joints, heart, blood vessels, inner ear, cornea and sclera.
► Clinical symptoms
Chondritis of the ear, nasal, laryngotracheal, costal and joint cartilages.
Inflammation of the eye and inner ear.
Collapse of laryngotracheal structures, subglottic area leading to increased upper airways infections and stridor.
Concurrent presence of vasculitis or glomerulonephritis may contribute to increased morbidity and mortality.
Clinical symptoms, the course of disease and response to treatment vary.
Relaxation An essential component of rehabilitation when both muscle and psychological relaxation occurs. Relaxation in the rhythm of breathing, autogenic training (Schultz’ autogenic training psychomotor relaxation therapy; Johannes Heinrich Schultz, German physician, 1884–1970), Jacobsons’ relaxation method (Edmund Jacobson, American physician, 1888–1983) and yoga elements are amongst such techniques.
Remicade Trade name of infliximab.
Remitting seronegative symmetrical synovitis with pitting oedema see Syndrome RS3PE (remitting seronegative symmetrical synovitis with pitting oedema).
Remsima Trade name of an infliximab biosimilar.
Reverse transcriptase An RNA-dependent DNA polymerase, which is the enzyme that synthesises DNA on the RNA chain matrix and transfers the genetic information from RNA into DNA. RNA viruses contain this enzyme.
Rhesus blood group system The set of antigens present on the surface of erythrocytes in humans and Rhesus apes (that is why Rh). They are encoded by gene locus on chromosome 1 which possesses at least three allele pairs Dd, Cc and Ee. The clinically most significant is antigen D, so individual is either rhesus factor positive (RhD+) or rhesus factor negative (RhD−) depending on whether they do or do not possess rhesus factor on the surface of their erythrocytes. Individuals who do not possess this antigen (RhD−) and receive erythrocyte RhD+ transfusion will develop alloantibodies directed against the antigen. Anti-RhD antibodies will evoke severe posttransfusion reactions during another transfusion of RhD+ blood. In pregnant women who are RhD− and who have a foetus with RhD+ erythrocytes (antigen RhD inherited from father), the transfer of foetal erythrocytes into maternal circulation (e.g. during labour or amniocentesis) may evoke the formation of anti-RhD antibodies. Such alloantibodies will cause haemolytic disease in newborns in subsequent pregnancies. Contrary to alloantibodies against ABO blood groups antigens, anti-Rh antibodies do not cause agglutination of Rh-positive erythrocytes and that is why they must be detected by a different method (Coombs test).
Rheumatic fever Systemic inflammatory disease which develops 2–5 weeks after infection with group A beta-haemolytic streptococcus. It is characterised by a number of pathological reactions in which the immune system is involved and which affect mainly the heart and joints.
► Clinical symptoms
The disease is characterised by fever, migratory arthritis and symptoms of rheumatic heart inflammation (carditis). The inflammation may affect endocardium, myocardium or pericardium – either selectively or completely (pancarditis). In certain cases, permanent heart damage may develop, primarily rheumatic valve disease. Central nervous system involvement can result in chorea, pneumonitis when the lungs are affected and erythema marginatum when the skin is affected. Laboratory findings include increased titre of streptococcal antibodies and the presence of elevated acute phase reactants.
Jones criteria JONES is an abbreviation summary often used to recall the major criteria (joints, O-shaped heart in imaging, nodules, erythema marginatum, Sydenham’s chorea). The presence of two major symptoms or one major +2 minor symptoms is necessary to make a diagnosis of rheumatic fever:
Major symptoms: migratory polyarthritis, carditis, chorea minor, erythema marginatum and rheumatic nodules
Minor symptoms: fever, arthralgias, increased erythrocyte sedimentation rate, elevated C-reactive protein, leucocytosis, the confirmation of beta-haemolytic streptococcus infection, prolonged P–R interval on ECG (first-degree heart block) and a history of rheumatic fever
Rheumatoid arthritis (RA) A common inflammatory joint disease that affects individuals of all ages, with maximal onset in women around the menopause. The disease is multifactorial in origin with certain genetic predispositions and unknown trigger factors. It is characterised by chronic inflammation, which is initiated and maintained by immunopathological mechanisms. The course of RA is very variable in pattern but generally is progressive and can lead to significant disability (Rovenský et al. 2000).
General features:
RA is not a benign disease as it shortens the life of affected individuals by 5–10 years.
Joint erosion develops early – usually during the first 2 years.
Early RA affects mainly the joints, and later systemic symptoms may develop.
Therapeutic management is effective particularly in the early stages of RA.
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