Rheumatology Flashcards
Presentation of antiphospholipid syndrome
CLOTS
- clots
- livedo reticularis (net like mottling of the skin)
- obstetric complications
- thrombocytopenia
Ix
- diagnostic blood tests:
- thrombocytopenia and a paradoxically prolonged APTT, as well as positive anti-phospholipid antibodies. These antibodies include anti-cardiolipin, anti-beta-2-glycoprotein-1 antibodies and lupus anti-coagulant.
What is Ewing’s sarcoma?
Malignant tumour that occurs most frequentlt in teh diaphyssi of the pelvis and long bones
- affects children
- onion skin appearance on xray
- fna of lesion shows EWS-FLI1 protein
Name benign bone tumours
- osteoma
- osteochondroma
- giant cell tumour
Name malignant bone tumours
- osteosarcoma
- Ewing’ sarcoma
- chondrosarcoma
What is an osteoma?
- benign ‘overgrowth’ of bone, most typically occuring on the skull
- associated with Gardner’s syndrome (a variant of familial adenomatous polyposis, FAP)
What is an osteochondroma?
- most common benign bone tumour
- more in males, usually diagnosed in patients aged < 20 years
- cartilage-capped bony projection on the external surface of a bone
What is a giant cell tumour?
- tumour of multinucleated giant cells within a fibrous stroma
- peak incidence: 20-40 years
- occurs most frequently in the epiphyses of long bones
- X-ray shows a ‘double bubble’ or ‘soap bubble’ appearance
What is an osteosarcoma?
- most common primary malignant bone tumour
- children and adolescents
- occurs in the metaphyseal region of long bones prior to epiphyseal closure:
- with 40% occuring in the femur, 20% in the tibia, and 10% in the humerus
- x-ray shows Codman triangle (from periosteal elevation) and ‘sunburst’ pattern
- mutation of the Rb gene significantly increases risk of osteosarcoma (hence association with retinoblastoma)
- other predisposing factors include Paget’s disease of the bone and radiotherapy
What is Chondrosarcoma?
- malignant tumour of cartilage
- most commonly affects the axial skeleton
- more common in middle-age
What is dermatomyositis
- an inflammatory disorder causing symmetrical, proximal muscle weakness and characteristic skin lesions
- may be from underlying malignancy
- 80% are ANA positive
What is Marfan’s syndrome?
Marfan’s syndrome is an autosomal dominant connective tissue disorder. It is caused by a defect in the FBN1 gene on chromosome 15 that codes for the protein fibrillin-1.
Common side effects of biphosphonates
- oesophageal reactions
- osteonecrosis of the jaw
- atypical stress fracture
- hypocalcaemia
Features of psoriatic arthropathy
- symmetrical polyarthritis
- asymmetrical oligoarthritis
- sacroilitis
CREST syndrome
Type of systemic sclerosis
- Calcinosis
- Raynaud’s phenomenon
- Oesophageal dysmotility
- Sclerodactly
- Telangiectasia
What is a type I hypersensitivity
- Anaphylaxis
- atopy (asthma, eczema, hayfever)
- Antigen reacts with IgE bound to mast cells
What is a type II hypersensitivity?
Cell bound
- Autoimmune haemolytic anaemia • ITP • Goodpasture's syndrome • Pernicious anaemia • Acute haemolytic transfusion reactions • Rheumatic fever • Pemphigus vulgaris / bullous pemphigoid
- IgG or IgM binds to antigen on cell surface
What is type III hypersensitivity?
Immune complex
Serum sickness
• Systemic lupus erythematosus
• Post-streptococcal glomerulonephritis
• Extrinsic allergic alveolitis (especially acute phase)
- Free antigen and antibody (IgG, IgA) combine
What is Type IV hypersensitivity
Delayes hypersensitivity
T cell mediated
Tuberculosis / tuberculin skin reaction • Graft versus host disease • Allergic contact dermatitis • Scabies • Extrinsic allergic alveolitis (especially chronic phase) • Multiple sclerosis • Guillain-Barre syndrome
Aspiration of gout shows
Negatively birefringent crystals
Blood tests of an osteomalacia patient
Low calcium and phosphate
High alkaline phosphotase
Treatment for osteomalacia
Vitamin D supplementation
- a loading dose is often needed initially
What is a poor prognosis for RA?
rheumatoid factor positive anti-CCP antibodies poor functional status at presentation X-ray: early erosions (e.g. after < 2 years) extra articular features e.g. nodules HLA DR4 insidious onset
Drug interactions of methotrexate?
avoid prescribing trimethoprim or co-trimoxazole concurrently - increases risk of marrow aplasia
high-dose aspirin increases the risk of methotrexate toxicity secondary to reduced excretion
*treatment of choice for methotrexate toxicity is folinic acid
X-ray findings of ankolysis spondylitis
Subchondral erosions, sclerosis and sqauring of lumbar vertebrae
Syndesmophytes
