Connective Tissue Disorders
Rheumatoid Arthritis
  • Symmetric polyarthritis due to inflammatory joint disease, RF seropositive
  • Aetiology; genetic predisoposition, autoimmune pathogenesis
  • Pathogenesis; circulation autoantibody/Rheumatoid factor (IgM molecule & sometimes IgG) > form complexes and deposit into joints > causing inflammation & destruction
  • Symptoms; oedema, painful, warm, skin redness, commonly effects; fingers > wrist > ankle > foot > elbow > shoulder
  • Pathological changes; Rheumatoid synovitis (swollen synovium > villous pattern (finger-like projections), articular cartilage destruction (presence of vascular granulation tissue & inflammatori fibrous pannus > joint deformity) & focal bone destruction (osteolytic mediated > deformity & oedema)
  • Clinical presentation; secondary fractures, rheumatoid nodules present
Osteoarthritis
  • Arises a a primary disorder (e.g. aging/wear&tear) or secondary as a joint abnormality
  • Asymmetric pathological changes (affecting cartilage, bone, synovium, joint capsule & sometimes bone)
  • Pathogenesis; destruction of articular cartilage > thickening of subarticular bone > osteophytes in joints (Heberden's/Bouchard's nodes; cyst formation)
  • Symptoms; pain, limited movement, oedema, paraesthesia (in spine)
  • Clinical classification; Primary generalised osteoarthritis (Heberden's nodes on fingers, PMP women effected), Erosive inflammatory osteoarthritis (rapid progression of inflammation & erosion) & Hypertrophic osteoarthritis (ostephyte formation/bone sclerosis, slowly progressive)
Autoimmune Arthritis
  • Seen in patients with; SLE, rheumatic fever & systemic sclerosis (RF seropositive)
  • Systemic lupus erythematosus; similar location to RA, rarely progressive & does not lead to chronic disease/joint deformity
  • Rheumatic fever; affects larger joints, transient features, no progression to chronic disease/joint deformity
  • Systemic sclerosis; systemic diseases affecting skin & organs, causes joint deformity like mild RA
Crystal Athropathies 
  • Features crystal deposits in joints & soft tissues
  • Pathogenesis; acute monoarthritis/oligoarthritis > chronic arthritis > secondary osteoarthritis
  • Types;
    • Urate gout ("True gout"); due to hyperuricaemia, caused by underexcretion of uric acid, overproduction of uric acid or enzyme defects of purine metabolism (congenital) > commonly affects podagra, precipitated by purine rich diet, pathogenesis; white powdery deposits within articular cartilage > degeneration, clinical presentation; foreign-body giant cell reaction > palpable mass (tophi)
    • Calcium pyrophosphate gout ("Pseudogout"); calcium deposits > producing chondrocalcinosis (possibly asymptomatic, primary in elderly/secondary in <60 with underlying cause, treated with reduced dietary calcium intake
Infective Arthritis
  • Aetiology; commonly pyogenic bacteria infection due to; access via local trauma, adjacent infective foci spread or bloodstream spread, prosthetic surgery or intra-articular injections of steroids (non-sterile)
  • Diagnosed; cytological examination of aspirated synovial fluid > will show elevated WBC & ESR
  • Types;
    • Tuberculous arthritis; may lead to osteomyelitis of VC > VC collapse > Pott's disease (in adults), hip & knee (children), diagnosed with synovial biopsy & culture analysis
    • Lyme disease; due to Borrelia burgdorferi (from infected body lice/ticks) > erythema chronicum migrans (peri bite) > chills, fever, fatigue, muscle aches & lymphadenopathy 
Seronegative Spondylarthritides (RF seronegative)
  • Aetiology; autoimmune reaction associated with high levels of antigen HLA B27
    • Ankylosing spondylitis (AS); Begins in lower VC > progresses slowly & unremittingly > inflammation of ligaments > dense fibrous/ossification of ligaments > fusion & rigid VC (bamboo spine) > recurrent iritis & aortic valve incompetence
    • Reiter's syndrome; comprised of reactive arthritis, urethritis & conjunctivitis, may present with "sausage digits", causes inflammation for ~6 months (no further progression), prognosis; spontaneous resolution or persistent symptoms
    • Psoriatic arthropathy; involves distal IP joints, symmetrical arthritis (sacroilitis & spondylitis) > ostelytic destruction/similar to RA
Osteogenesis Imperfecta
  • Autosomal recessive/dominant inheritance disorder > abnormal collage formation in osteoid > spontaneous fracture or deformity
  • Clinical features; abnormal tooth formation, pale-blue sclera
Developmental Hip Dysplasia
  • Congenital structural abnormality > shallowness, laxity & stretching of ligaments > dislocation or subluxation
  • Treated with; splints & harness in the flexed/abducted position
  • May lead to abnormal gait, hip pain & premature osteoarthritis if untreated
Bone Disorders
Subcutaneous Lipoma
  • Benign tumour of subcutaneous fat (very common)
  • Clinical features; solitary, slow growing, soft, lobulated, well circumscribed, may be angiolipoma or fibrolipoma > may lead to liposacroma
Benign Fibrous Histiocytoma (Dermatofibroma)
  • Derived from primitive fibroblasts in dermis (very common)
Malignant Fibrous Histiocytoma (MFH)
  • Malignancy of soft-tissues
  • Clinical presentation; enlarging, painless mass, deep in thigh/lower leg (rare)
Rhabdomyosarcoma
  • Malignancy of primitive striated muscle cells
  • Types; Embryonal (in children affecting pelvic region & head/neck) & Alveolar (in adolescent muscles of limbs)
Systemic Lupus Erythematosus
  • Aetiology; production of autoantibodies (ANA vs nuclear DNA) > type III hypersensitivity
  • Pathogenesis; immune complexes deposit in tissue > causing acute inflammation
  • Involves synovial joints, skin, kidneys & brain
  • Presentation; discoid skin rash (round red scaly telangiectatic plaques), malar skin rash ("butterfly" rash), oral ulceration, renal abnormality, immunology/haematological involvement, serosal inflammation, polyathralgia
Systemic Sclerosis
  • Aetiology; produced of autoantibodies (anti-centromere & anti-scl70 antibodies vs DNA & topoisomerase I) (AutoAbs vs DNA)
  • Pathogenesis; formation of fibro collagenous tissue > rigidity of affected tissue > destruction of specialised cells > vessel wall thickening & perivascular fibrosis > ischaemic damage
  • Clinical presentation; scleroderma (dermal thickening > increased rigidity with tightening & atrophy of epidermis)
  • Complications; oesophageal strictures, pulmonary fibrosis, vascular renal damage, sclerosis of subcutis, acrosclerosis calcinosis cutis, Raynaud's phenomenon

 

Soft Tissue Tumours
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