IM7.1-22 | Rheumatologic Problems — Glossary

A scoring system for classifying definite RA: ≥6 points from four domains — joint involvement (0–5), serology — RF/anti-CCP (0–3), acute-phase reactants — ESR/CRP (0–1), symptom duration (0–1); designed for classification of early RA in patients with synovitis who cannot be otherwise explained.

A xanthine oxidase inhibitor used for urate-lowering therapy in gout; reduces uric acid synthesis; must NOT be started during an acute gout attack (precipitates mobilisation of crystals and worsens inflammation); started 4 weeks after the acute attack resolves; target serum urate <6 mg/dL.

A rare but potentially fatal drug reaction to allopurinol characterised by fever, widespread maculopapular rash progressing to Stevens-Johnson syndrome/TEN, hepatitis, eosinophilia, and renal failure; higher risk in HLA-B*5801 carriers (more prevalent in Han Chinese, Korean, Thai populations) and in patients with CKD started on high allopurinol doses.

A normocytic, normochromic anaemia seen in chronic inflammatory states (RA, SLE, vasculitis); caused by cytokine-mediated hepcidin elevation reducing iron availability for erythropoiesis, not true iron deficiency; serum ferritin is normal or elevated, distinguishing it from iron-deficiency anaemia.

Normocytic normochromic anaemia caused by inflammatory cytokines that sequester iron in reticuloendothelial cells, reduce erythropoietin responsiveness, and shorten red cell survival; common in RA, SLE, and other chronic inflammatory conditions; distinguished from iron deficiency by low serum iron with normal or elevated ferritin.

An autoantibody directed against citrullinated proteins; specificity 95–98% for RA, higher than RF; positive in ~50% of seronegative RA patients; high titres predict erosive disease; can precede clinical RA by 5–10 years.

An autoantibody against double-stranded DNA; specificity 97% for SLE; sensitivity 57–70%; titres correlate with disease activity, particularly lupus nephritis; rising anti-dsDNA with falling complement precedes flare.

An autoantibody against the Smith nuclear antigen; specificity ~99% for SLE; sensitivity only 25–30%; a positive anti-Sm in a clinical context consistent with SLE is essentially diagnostic.

A group of autoantibodies against nuclear components (DNA, histones, ribonucleoproteins); sensitivity 95–98% for SLE (a screening test); specificity only 57–74%; positive in many non-SLE conditions including thyroid disease, fibromyalgia, and in low titre in healthy individuals; always requires specific antibody follow-up.

Joint pain without objective evidence of inflammation — no warmth, swelling, effusion, or restricted ROM detectable on examination; a subjective symptom only. Distinct from arthritis, which requires objective signs of synovial inflammation.

Aspiration of synovial fluid from a joint using a needle; indicated for acute monoarthritis (to exclude septic arthritis), diagnosis of crystal arthropathy, therapeutic drainage of tense effusion, or intra-articular injection; synovial fluid is sent for cell count, differential, Gram stain, culture, and crystal analysis.

A radiographic appearance of the lumbar and thoracic spine in advanced ankylosing spondylitis — vertical bridging syndesmophytes (bony bridges between vertebral bodies via ossification of the annulus fibrosus) create a continuous bony column resembling bamboo.

The clinically important distinction between achieving target disease activity scores (e.g., DAS28 <2.6 in RA) by clinical and laboratory measures (biological remission) and achieving the patient's subjective goals of adequate function, well-being, work participation, and quality of life (patient remission); the two may not coincide — a patient in DAS28 remission may still have significant functional disability (HAQ ≥1.0) or depression (PHQ-9 ≥10).

A model of illness proposed by Engel (1977) that considers three interacting dimensions of health: biological (disease, inflammation, organ damage), psychological (mood, coping style, pain cognitions, self-efficacy), and social (employment, family support, financial resources, cultural context); the governing framework for understanding QoL impact in chronic rheumatologic disease.

A finger deformity in RA characterised by PIP flexion and DIP hyperextension; results from rupture of the central slip of the extensor tendon at the PIP joint (the lateral bands displace volar, acting as flexors); limits finger extension.

Inflammation of a bursa (fluid-filled sac that reduces friction near joints); produces localised, fluctuant, tender swelling over the bursa — distinct from joint effusion; common sites: prepatellar (housemaid's knee), olecranon (often gout or RA), subacromial (shoulder impingement), trochanteric (lateral hip pain).

A state of amplified pain processing in the central nervous system whereby pain signals are perceived as more intense and widespread than expected from the peripheral tissue damage; common in RA and fibromyalgia overlap; contributes to persistent pain in patients in clinical remission by DAS28; requires non-pharmacological management (CBT, graded exercise, low-dose amitriptyline).

Measured at the nipple line as the difference between maximum inspiration and forced expiration; normal ≥5 cm; reduced expansion (<2.5 cm) indicates costovertebral joint involvement in ankylosing spondylitis; assessed as part of the spinal examination in spondyloarthropathy.

Post-translational modification of arginine to citrulline, catalysed by PAD enzymes; induced by smoking and NETosis in the lung; generates citrullinated proteins that trigger anti-CCP antibody production in HLA-DR4 carriers — an early event in RA pathogenesis, often preceding joint symptoms by years.

A plant-derived anti-inflammatory agent that inhibits microtubule polymerisation, blocking neutrophil activation and crystal phagocytosis; first-line for acute gout (0.5 mg 2–3 times daily); also used for prophylaxis during ULT initiation (0.5 mg twice daily for 3–6 months); dose-reduce in renal and hepatic impairment; toxicity: diarrhoea, nausea, myopathy in overdose.

Diffuse swelling of an entire digit (finger or toe) from base to tip due to simultaneous inflammation of the flexor tendon sheath and all interphalangeal joints; the 'sausage digit'; a hallmark of psoriatic arthritis and reactive arthritis (spondyloarthropathies).

Disease Activity Score 28 — a composite score of rheumatoid arthritis activity based on swollen and tender joint counts (28 joints), patient global assessment, and CRP or ESR; DAS28 <2.6 = remission; 2.6–3.2 = low; 3.2–5.1 = moderate; >5.1 = high disease activity.

Inflammation at the enthesis — the insertion point of a tendon, ligament, or joint capsule into bone; a pathological hallmark of seronegative spondyloarthropathies (ankylosing spondylitis, psoriatic arthritis, reactive arthritis); common sites include the Achilles tendon insertion, plantar fascia origin, and patellar tendon.

Hip Flexion, ABduction, External Rotation test — the hip is placed in the figure-4 position and the knee is pressed down while the contralateral pelvis is stabilised; pain in the ipsilateral groin suggests hip pathology; pain posteriorly over the contralateral sacroiliac joint indicates sacroiliac joint disease.

A 13-item patient-reported fatigue scale scored 0–52, where lower scores indicate more fatigue; a score ≤30 is considered clinically significant fatigue; used in RA and SLE to quantify fatigue, which is often the most disabling symptom but correlates poorly with joint counts or inflammatory markers.

Folic acid 5 mg once weekly, prescribed on a different day from the MTX dose; reduces MTX-induced mucositis, nausea, alopecia, and hepatotoxicity by ~79% without reducing efficacy; its omission when prescribing methotrexate is a medication safety error.

A 7-item validated tool for anxiety screening and severity assessment, scored 0–21; ≥10 indicates moderate anxiety; commonly administered alongside PHQ-9 in rheumatologic clinic settings.

Gait, Arms, Legs, Spine — a validated 2–3 minute rapid musculoskeletal screening assessment developed by Doherty et al. (1992); identifies abnormal regions that require detailed regional examination; recommended as the standard approach to musculoskeletal screening in general medical practice.

Violaceous (purple-pink) papules over the dorsal surface of the MCP and PIP joints; a pathognomonic sign of dermatomyositis; often associated with heliotrope rash (purple discolouration of the upper eyelids) and proximal muscle weakness.

A structured, progressively increasing aerobic exercise programme (walking, swimming, cycling) that is the most evidence-based non-pharmacological intervention for fatigue in RA and AS; counter-intuitive to patients who associate exercise with pain — needs to be explicitly prescribed and explained; does not worsen joint inflammation when performed appropriately.

The most widely used PROM for RA; assesses functional disability across 8 activity categories (dressing, arising, eating, walking, hygiene, reach, grip, usual activities); scored 0–3; ≥1.0 indicates significant disability correlating with work incapacity; MCID 0.22.

The subjective perception of health across physical functioning, role functioning, mental health, and vitality as it relates to the impact of illness and its treatment; distinguished from general quality of life by its focus on the health-related aspects; measured by patient-reported outcome measures (PROMs).

Bony swellings (osteophytes) at the DIP joints of the fingers in osteoarthritis; represent cartilage loss and subchondral bone remodelling; typically hard, not tender in established disease; distinguish OA from RA (which spares the DIP joints).

A purple-red discolouration of the upper eyelids, sometimes with periorbital oedema; a characteristic feature of dermatomyositis; named after the heliotrope flower; often associated with Gottron's papules and proximal myopathy.

An HLA class I allele present in ~8% of the Indian general population; strongly associated with seronegative spondyloarthropathies — ankylosing spondylitis (~95%), reactive arthritis (~75%), psoriatic arthritis with axial disease (~50%), and IBD-associated axial disease.

A HLA class II allele (particularly HLA-DRB104:01 and 04:04) strongly associated with rheumatoid arthritis; contains the shared epitope — a specific amino acid sequence in the peptide-binding groove that presents citrullinated peptides to autoreactive T cells.

An antimalarial drug used in mild RA and SLE (all SLE patients); inhibits lysosomal function in antigen-presenting cells, reducing inflammation; safe in pregnancy; requires annual ophthalmology review after 5 years to detect retinopathy (cumulative dose-related).

A WHO framework classifying the consequences of health conditions at three levels: impairment (structural/functional abnormality), activity limitation (difficulty executing tasks), and participation restriction (problems with involvement in life situations); provides a structured approach to understanding the full impact of rheumatologic disease beyond laboratory and imaging findings.

Back pain meeting specific criteria suggesting spondyloarthropathy: onset before 40 years, insidious onset, improvement with exercise (not rest), pain at night (improving on getting up), and morning stiffness >30 minutes; contrasted with mechanical low back pain which worsens with exercise and improves with rest.

A non-erosive, reducible deformity of the hands in SLE, resembling RA with ulnar deviation — but the joints can be passively corrected (no fixed erosion). Caused by tendon laxity without synovial pannus formation; distinguishes SLE arthritis from RA.

Targeted synthetic DMARDs that inhibit Janus kinase enzymes (JAK1, JAK2, JAK3, TYK2), blocking intracellular cytokine signalling pathways; examples include tofacitinib, baricitinib, upadacitinib; oral small molecules; used in RA after DMARD failure; associated with increased infection risk and (at higher doses) cardiovascular and thromboembolic risk.

Renal involvement in SLE from immune complex deposition in the glomerulus; classified by ISN/RPS into classes I–VI; class III (focal) and IV (diffuse) proliferative nephritis are the most severe and require immunosuppressive therapy; proteinuria and haematuria on urine dipstick are the clinical markers.

Fixed erythema over the cheeks and nasal bridge in a butterfly distribution, sparing the nasolabial folds; photosensitive; a characteristic feature of SLE (one of the ACR/SLICC classification criteria); caused by immune complex deposition in dermal capillaries triggered by UV radiation.

A radiographic finding in RA — well-defined defects at the joint margins at the 'bare area' (uncovered by cartilage), where synovial pannus erodes bone directly; best seen at the radial aspect of the 2nd and 3rd MCP joints; indicates structural damage requiring urgent DMARD therapy.

Transverse compression of all metacarpophalangeal joints simultaneously by squeezing firmly across the metacarpal heads; tenderness indicates MCP synovitis; one of the most sensitive bedside signs for early rheumatoid arthritis, detectable before visible swelling develops.

Hyperkeratotic, cracked skin on the lateral aspects and palmar surface of the fingers, resembling the hands of a manual labourer; a skin sign of dermatomyositis and anti-synthetase syndrome (associated with anti-Jo-1 antibodies); also associated with interstitial lung disease.

Transverse compression across the metatarsal heads of the foot; tenderness indicates MTP synovitis; along with MCP synovitis, a hallmark of RA (the MTP joints are the second most commonly affected joints in RA after the hand joints).

The cornerstone first-line conventional synthetic DMARD for RA; given 10–25 mg/week (oral or subcutaneous) with folic acid supplementation; mechanism involves inhibition of dihydrofolate reductase and adenosine-mediated anti-inflammatory effects; requires monitoring of LFT, CBC, and renal function; teratogenic — contraindicated in pregnancy.

The anchor conventional DMARD for RA; inhibits dihydrofolate reductase, reducing purine/pyrimidine synthesis in activated T and B cells; given once weekly at 7.5–25 mg; must be co-prescribed with folic acid 5 mg/week (different day); hepatotoxic, teratogenic — contraindicated in pregnancy and significant alcohol use.

An acute gout attack triggered by a rapid fall in serum uric acid during urate-lowering therapy initiation, as stored urate crystals are mobilised from tissues into the joint space; prevented by co-prescribing prophylactic colchicine 0.5 mg twice daily for the first 3–6 months of ULT.

A proposed mechanism of autoimmunity in which microbial antigens share structural similarity with self-peptides; immune responses against the pathogen cross-react with host tissues; examples include Klebsiella nitrogenase homology with HLA-B27 in ankylosing spondylitis and Streptococcal M protein similarity with cardiac myosin in rheumatic fever.

Gel phenomenon in inflamed joints after rest — cytokines and inflammatory mediators accumulate overnight; stiffness lasting ≥1 hour is a hallmark of inflammatory arthritis (RA); stiffness lasting <30 minutes is characteristic of mechanical/degenerative disease.

A prodrug that inhibits inosine monophosphate dehydrogenase, selectively suppressing lymphocyte proliferation; used for induction and maintenance of lupus nephritis (class III/IV); preferred over cyclophosphamide in Indian patients for maintenance; teratogenic — contraindicated in pregnancy.

The optical property of monosodium urate crystals under compensated polarised light — they appear YELLOW when their long axis is parallel to the first-order red compensator's slow axis (and blue when perpendicular); needle-shaped, diagnostic of gout.

A bony outgrowth at the joint margin, formed in response to increased mechanical stress on the subchondral bone; the radiographic hallmark of osteoarthritis; occurs at the knee tibial plateaux, acetabular rim, vertebral endplates, and DIP/PIP joints.

A cognitive-emotional pain response characterised by a tendency to magnify pain, ruminate about it, and feel helpless in response to it; the strongest psychological predictor of disability in RA, exceeding joint count and radiographic damage in predictive value; measured by the Pain Catastrophising Scale (PCS); a target for cognitive-behavioural therapy.

Invasive granulation tissue arising from inflamed synovium in RA; invades articular cartilage and subchondral bone, producing the characteristic erosions seen on X-ray. Driven by activated synoviocytes, macrophages, and cytokines including TNF-α and RANKL.

A standardised, validated questionnaire completed by the patient (not the clinician) to quantify health-related quality of life, functional status, pain, fatigue, or psychological well-being; examples include HAQ-DI, SF-36, PHQ-9, FACIT-Fatigue; essential for capturing dimensions of disease impact not visible in clinical or laboratory assessments.

Localised loss of bone density around a joint, visible on plain X-ray as decreased radiodensity of the periarticular bone; an early radiographic sign of rheumatoid arthritis, reflecting the local bone-resorbing effect of inflammatory cytokines.

A 9-item validated screening and severity tool for major depression, scored 0–27; ≥10 indicates moderate depression requiring clinical management; administered at clinic visits for patients with chronic rheumatologic disease; when PHQ-9 ≥10, referral to psychological services or initiation of antidepressant therapy is indicated.

Acute gout of the first metatarsophalangeal (MTP) joint — the classic presentation of gout; the joint is red, hot, severely swollen, and exquisitely tender; the attack typically resolves within 1–2 weeks untreated and recurs at variable intervals.

The optical property of calcium pyrophosphate dihydrate crystals under compensated polarised light — they appear BLUE when their long axis is parallel to the compensator's slow axis (and yellow when perpendicular); rhomboid-shaped, diagnostic of pseudogout.

The probability that a patient with a positive test result truly has the disease; dependent on both test specificity and pre-test probability (disease prevalence in the tested population); explains why a positive ANA has different clinical significance in a young woman with multisystem SLE features versus an asymptomatic healthy woman.

Weakness predominantly affecting the shoulder and hip girdle muscles (proximal limb-girdle distribution); patients cannot rise from a chair without arm support, cannot raise arms above the head, and struggle with stairs; when combined with elevated CK and skin changes, indicates inflammatory myopathy (polymyositis/dermatomyositis).

A radiographic finding in chronic tophaceous gout — well-defined, round, lytic lesions with overhanging margins (rat-bite appearance), occurring adjacent to tophi deposits; the joint space is notably preserved until late disease, distinguishing gout erosions from RA erosions.

A cytokine produced by activated T cells and synoviocytes in RA that stimulates osteoclast differentiation and bone resorption, producing the characteristic periarticular erosions seen on X-ray; the target of denosumab in osteoporosis.

An aseptic inflammatory arthritis triggered by a preceding infection (enteric — Salmonella, Shigella, Yersinia, Campylobacter; or genitourinary — Chlamydia trachomatis) in a genetically susceptible host (HLA-B27 positive in ~75%); the classic triad is arthritis + urethritis/cervicitis + conjunctivitis/uveitis (Reiter syndrome).

An IgM autoantibody directed against the Fc portion of IgG; present in 70–80% of RA patients but also in Sjögren syndrome, hepatitis C, endocarditis, and 5% of healthy elderly individuals; sensitivity ~70–80%, specificity ~80% for RA.

An Indian legislation that recognises RA, SLE, and ankylosing spondylitis (meeting severity criteria) as disabilities, entitling affected individuals to employment accommodations, educational reservations, disability benefit schemes, and protection from workplace discrimination; a social determinant of QoL relevant to rheumatology clinical practice.

Inflammation of the sacroiliac joints; the earliest and most diagnostic radiographic finding in ankylosing spondylitis; appears as sclerosis, irregularity, and erosions at the SI joint margins on AP pelvis X-ray; graded 0–4 by the modified New York criteria.

Assessment of lumbar flexion: a mark is placed 10 cm above and 5 cm below the lumbosacral junction (15 cm total); on maximal forward flexion, the distance should increase to ≥20 cm; an increase <20 cm indicates restricted lumbar mobility as seen in ankylosing spondylitis.

Tight, thickened skin binding the fingers in systemic sclerosis; results from dermal fibrosis; leads to restricted finger flexion and a characteristic tapered, shiny appearance of the fingers; associated with Raynaud's phenomenon, nail fold capillary abnormalities, and digital ulcers.

RA in which both RF and anti-CCP are negative; accounts for approximately 30% of RA cases; diagnosis is based on clinical criteria (ACR/EULAR 2010 scoring) without serological support; generally associated with milder disease and lower erosive risk than seropositive RA.

A generic health-related QoL questionnaire measuring 8 health domains and producing two summary component scores — Physical Component Summary (PCS) and Mental Component Summary (MCS); used to compare QoL with population norms across disease types.

A six-step structured approach to breaking bad news and communicating serious diagnoses: Setting, Perception (what does the patient know?), Invitation (how much does the patient want to know?), Knowledge (giving information in plain language), Empathy (acknowledging the emotional response), Summary and Strategy (next steps); adapted for use in chronic inflammatory disease diagnosis disclosure.

Increased radiodensity of the bone immediately beneath narrowed cartilage in osteoarthritis; reflects reactive bone remodelling (eburnation) in response to increased mechanical load; seen alongside joint space narrowing and osteophytes.

A finger deformity in RA characterised by PIP hyperextension and DIP flexion; results from volar plate laxity at the PIP joint and tightening of the central extensor tendon; limits grip and pinch function.

Boggy, rubbery, non-fluctuant swelling around a joint due to hypertrophy of the inflamed synovial membrane; distinguished from a synovial effusion (which is fluctuant) and from bony swellings (osteophytes in OA, which are hard and non-tender); characteristic of RA at the MCP and PIP joints.

Inflammation of the synovial membrane lining a joint, producing warmth, swelling (effusion or synovial thickening), tenderness, and restricted range of motion; the hallmark of inflammatory arthritis.

Mandatory pre-biologic workup including QUANTIFERON-TB Gold (IGRA) and chest X-ray; required before TNF inhibitors, IL-6 inhibitors, and JAK inhibitors; in India, every patient should be screened; latent TB must be treated with isoniazid preventive therapy (IPT) for 6–9 months under NTEP guidance before or concurrent with biologic initiation.

A class of biologic DMARDs that block tumour necrosis factor-alpha (TNF-α), a key proinflammatory cytokine in RA, AS, and psoriatic arthritis; examples include adalimumab (SC), etanercept (SC), infliximab (IV), certolizumab (SC), golimumab (SC); require pre-treatment TB screening; reactivate latent tuberculosis.

A management strategy in RA in which therapy is escalated until a specific disease activity target (remission: DAS28 <2.6, or low disease activity: DAS28 2.6–3.2) is achieved; endorsed by ACR and EULAR; associated with better long-term outcomes than symptom-driven management.

Long-term pharmacological reduction of serum uric acid to <6 mg/dL (target <5 mg/dL in tophaceous gout) to prevent recurrent gout attacks, tophi, and urate nephropathy; primary agent is allopurinol; indicated for ≥2 gout attacks per year, tophi, urate nephropathy, or recurrent renal calculi.

The concept that early aggressive DMARD therapy in the first 3–6 months of RA produces better long-term outcomes (remission, less erosive damage) than delayed treatment, even if the same disease activity level is treated later; used as a communication tool to motivate early treatment adherence.

Inability to maintain paid employment due to rheumatologic disease; occurs in 30–50% of RA patients within 10 years of diagnosis; prevented by early DMARD initiation (treat-to-target), occupational therapy, ergonomic workplace adjustment, and disability rights advocacy; classified under the RPwD Act 2016 in India when severity criteria are met.

A validated patient-reported questionnaire measuring the impact of chronic disease on work and daily activities; generates four subscores — absenteeism (hours absent due to illness), presenteeism (performance impairment while at work), overall work impairment, and activity impairment; used in rheumatology to quantify occupational impact.