Rheumatology - general Flashcards
Which is more common?
RA or OA?
OA
Pathophysiology of OA
Imbalance between cartilage degeneration and bone remodelling
Chronic slowly progressive disorder due to failure of articular cartilage (wear + tear)
Non-inflammatory degenerative process
Localised loss of cartilage
Remodelling of adjacent bone
Associated inflammation
Pathophysiology of RA
Active symmetrical arthritis lasting >6 weeks
Chronic (>6 weeks) autoimmune disease characterised by
Symmetrical deforming polyarthritis (>4 joints)
Extra-articular manifestaions
Site of inflammation - synovium
HLA associations in RA
HLA-DR1
HLA-DR4
Difference of primary vs secondary amyloidosis
Primary amyloidosis - AL amyloidosis
– Deposition of immunoglobulin light chain
- Plasma cell disorders e.g. MM
Secondary amyloidosis - AA amyloidosis
– Deposition of serum amyloid A
- Chronic inflammation e.g. RA, IBD, chronic infection
Seronegative spondyloarthritis = PEAR HEADS
Psoriatic arthritis
Enteropathic arhtirits
Ankylosing spondylitis
Reactive arthritis
HLA B27 Enthesitis Assymetrical oligoarthritis + axial involvement + extra-articular involvement Dactylitis Seronegative
Pathophysiology of ankylosing spondylitis
- Autoimmune chronic progressive inflammatory disease
- Destruction of interverbral joints, facet joints, sacroiliac joint
- Fibroblasts replace destroyed joint with fibrin
- Fibrous bands around joint limit range of motion
- Ossification
- HLA-B27
- Peak onset 20-30
- M>F
Define reactive arthritis
Sterile inflammation in joints 2 weeks after extra-articular infection
Urogenital (chlamydia, HIV, c.trichomatis, gonorrhoea) GI infections (salmonella, shigella, campylobacter, c difficile, giardia lamblia)
Define septic arthritis
Infection causing inflammation in a native or prosthetic joint
Most common pathogen
children - haemophilus influenzae
<30 years - N. gonorrhoea
>30 years - Staph aureus
surgical emergency! (joint destruction <24h)
Composition of crystals in gout vs pseudogout
Gout - monosodium urate crystals
Gout - excessive production of uric acid
Pseudogout - calcium pyrophosphate crystals
pseudogout - excessive production of pyrophosphate
When do acute gout attacks usually happen?
Tend to happen after
- a large meal with foods rich in purines (shellfish, anchiovies, red meat)
- alcohol consumption
- dehydration
- diuresis
- surgery
- trauma
RF for pseudogout
- Hyperparathyroidism
- Hypothyroidism
- Hypomagnesemia
- Hypophosphatesia
- Haemochromatosis
- Acromegaly
- Wilson’s disease
Elderly women
RF for gout
- Chemo/radiation (tumour lysis syndrome)
- Obesity, DM, HTN, dyslipidaemia
- Consumption of purine rich foods (shellfinsh, anchiovies, red meat), alcohol
- Underexcretion of uric acid by the kidney (renal failure, thiazide + loop diuretics, aspirin, pyrazinamide, cyclosporin)
Obese middle aged men
Definition of osteomyelitis
Infection of the bone marrow which can spread to the bone cortex + periosteum via the Haversian canals
Results in an inflammatory destruction of the bone and if the periosteum becomes involved it can result in necrosis
What is a sequestrum and an involucrum?
Processes that happen during chronic osteomyelitis
- Sequestrum - Necrotic bone separates from healthy part of bone
- Involucrum - osteoblasts (originate from periosteum) may form new bone that wraps the sequestrum in place
Most common organisms that cause osteomyelitis in
a) most common
b) sickle cell disease
c) cat/dog bite, scratch
a) staph aureus
b) staph aureus + salmonella
c) pasturella multocida
Way in which osteomyelitis can spread
• Hematogenous spread (most common)
(Immunocompromised, DM, IVDU, Haemodialysis, Dental extraction of infected tooth)
- Contiguous spread (cellulitis, localised infection, neuropathic ulcer)
- Direct/Trauma (Penetrating injuries)
- Surgery
Most common site of osteomyelitis in adults vs children
Adults – cancellous bone, vertebrae (affects the 2 vertebrae + the intervertebral disc in between them, can result in vertebral abscess causing neural compression + spinal instability)
Children – metaphysis of long bones (femur, proximal tibia)
Feet commonly affected in diabetics (neuropathic ulcers get infected –> contiguous spread)
Definition of idiopathic inflammatory myopathies
- Autoimmune disorders that cause muscle inflammation –> muscle weakness –> wasting
- Therefore in individuals with gradually progressive muscle weakness, suspect inflammatory myopathy
refers to a group of 3 disorders – polymyositis, dermatomyositis, inclusion body myositis
Polymyositis typically affects adults (F>M)
Dermtomyositis mainly affects children (F>M)
Inclusion body myositis - the most common inflammatory myositis in individuals >50 years (M>F)
Sarcoidosis definition
multisystem chronic granulomatous inflammatory condition characterised by the formation of non-caseating granulomata at various sites in the body
• Commonly affect lungs, skin, eyes
• Accumulation of lymphocytes + macrophages - formation of non-caseating granulomas in the lungs and other organs
RF
• FHx
• Prior infection with M tuberculosis + Borrelia burgdorferi
• Bimodal distribution – peaks in 30s and 50s
• African-Americans
• F>M
SLE pathophysiology
inflammatory, multisystem, autoimmune disease
DR2
DR3
Immune system recognizes nuclear antigens as foreign and tries to attack them
Type III hypersensitivity rxn - Ag-Ab complexes are deposited in vessels in various organs
Type II hypersensitivity rxn - ab targeting RBC, WBC, plt –> pancytopenia
What is scleroderma +
Which are the 2 types of scleroderma and what is their difference?
- Rare multisystem autoimmune disorder
- Increased fibroblast activity –> abnormal growth of connective tissue –> fibrosis of organs + vasculature
Limited cutaneous scleroderma/CREST syndrome
• More common type
• Slower progression
• No sign of internal organ involvement
• Limited to face, distal limbs (blow the elbow + knees)
Diffuse cutaneous scleroderma
• Faster progression
• Internal organ involvement
• Can affect the entire body
What does fundoscopy show on a pt w GCA?
- Pallor
- Oedema of the optc disc
- Cotton wool spots
- Small haemorrhages
- Cherry spot on macula (if there is retinal artery thrombosis)
What is not a symptom of polyarteritis nodosa?
No glomerulonephritis
Pulmonary arteries spared
