MSK Flashcards
What does arthropathy mean?
Something wrong with a joint
What does arthralgia mean?
Joint pain
What is arthritis?
Joint inflammation
What are the common features of inflammatory conditions?
Joint pain with diurnal variation
Morning stiffness
Synovitis (soft tissue swelling)
What are the common features of mechanical conditions?
Worse with activity
Generally localised
Normal blood tests
Give an example of an inflammatory joint condition
RA
Give an example of a non-inflammatory joint condition
OA
Give an example of an inflammatory condition not related to the joint
Giant cell arteritis
Give an example of an non-inflammatory condition not related to the joint
Fibromyalgia
What are the 3 types of inflammatory joint conditions?
Connective tissue diseases and vasculitides (group of diseases that destroy blood vessels by inflammation)
Sero-negative arthritides
Crystal arthropathies
Give examples of the Connective tissue diseases and vasculitides.
RA
SLE
Scleroderma
Wegener’s granulomatosis
Give examples of Sero-negative arthritides
Ankylosing spondylitis
Psoriatic arthritis
Reiters syndrome
Gut associated arthropathy
Give examples of crystal arthropathies
Gout
Pseudogout
What is enthesitis?
Inflammation of the area where tendons and ligaments insert into bone
What are some of the extra-articular symptoms of RA?
Raynauds Sicca (mucosal dryness) ILD Neuropathy Vasculitis
What are some of the extra-articular symptoms of sero-negative arthritides?
Psoriasis
Uveitis/iritis
Tendonitis
IBD
What does LOSS describe with relation to OA?
Loss of cartilage
Osteophyte formation
Subchondral cysts
Subchondral sclerosis (hardening of tissue)
How can connective tissue diseases as a group be defined as?
They have spontaneous over-activity of the immune system and are often associated with specific auto-antibodies
What is SLE?
A systemic AI disease that can affect any part of the body resulting in inflammation and tissue damage.
Is SLE commoner in males or females?
Females
Per 100,000 people, how many will have SLE?
20-150 depending on the ethnic group
There are 4 factors which can influence SLE development, what are these?
Genetic
Environmental
Hormonal (higher oestrogen exposure)
Immunological
What environmental factors can influence SLE development?
Viruses e.g. EBV
UV light
Silica dust is cigarette smoke and cleaning powders
Name some of the general symptoms of SLE
Fever Malaise Poor apetite Weight loss Fatigue
What are the mucocutaneous features of SLE?
Photosensitivity
Malar rash
Discoid lupus erythematosus
Subacute cutaneous lupus
What are the MSK features of SLE?
Non-deforming polyarhritis
Jaccoud’s arthritis = deforming arthropathy
Myopathy - weakness, myalgia (muscle pain) and myositis (muscle inflammation)
What are the pulmonary features of SLE?
Pleuricy Infection Diffuse lung infiltration and fibrosis Pulmonary hypertension Pulmonary infarct
What are the cardiac features of SLE?
Pericarditis
Cardiomyopathy
Pulmonary hypertension
Libmen Sacks endocarditis (sterile)
Golemulonephritis can occur in SLE, what does this present with?
Proteinuria
Hypertension
Acute or chronic renal failure
What are the neurological features of SLE?
Depression Migranous headache TIA/stroke Cranial/peripheral neuropathy Cerebellar ataxia (condition affecting balance)
What are the haematological features of SLE?
Lymphadenopathy (v.common)
Leucopenia (low WBC)
Anaemia
Thrombocytopenia (low platelets)
SLE can also increase an individuals susceptibility to infection. Why is this?
Individual has a compromised immune system and drugs used to treat lupus can compromise immune system more.
What screening tests would be done for an individual with suspected SLE?
FBC Renal function tests Anti-nuclear antibody Anti-double stranded DNA antibodies ENA Complement levels
ANA is present in what % of SLE patients?
What is the downside of ANA?
95%
20% of the healthy population have positive ANA. Also found in a variety of other conditions
A positive ANA test should be taken seriously if they have CTD symptoms or if other antinuclear antibodies are positive; what are these other autoantibodies?
Anti-dsDNA
Anti-Sm
Anti-Ro
Anti-RNP
How often does anti-dsDNA occur in SLE patients?
60% of patients
Highly specific for SLE
What is Anti-Ro associated with?
Anti-La and cutaneous manifestations
Also neonatal LE
How do you monitor SLE activity?
BP Anti-dsDNA levels - +ve correlation C3/C4 levels - -ve correlation Urine FBC and blood biochem
What is the 1st thing tried to treat mild SLE?
NSAIDs and simple analgesia
What other drug treatment can be used in SLE?
Anti-malarials: Chloroquine and hydroxychloroquine
Steroids: dose and type depends on symptoms
Immunosuppressives:
azathioprine, cyclophosphamide, methotrexate, mycophenolate mofetil
Biologics:
Rituximab and Belimumab
What is sjogrens syndrome?
AI condition - lymphocyte infiltration of exocrine glands causing xerostomia and keratoconjunctivitis sicca (dry mouth and dry eyes)
What are the classification criteria for Sjogrens?
Ocular symptoms (daily for >3 months) Oral symptoms (daily for >3 months) Evidence of ocular dryness Evidence of salivary gland involvement Immunology - Ro, La, or both Biopsy evidence of lymphocytic infiltrate
Must have 4 of 6 inc. Immunology or biopsy
What test can be done to prove Sjogrens clinically?
Schirmers test
What classifies secondary Sjogrens syndrome?
Caused by or alongside other AI conditions
What other manifestations of Sjogren’s disease are there?
Fatigue, arthralgia, raynauds, ILD, neuropathy, skin and vaginal dryness, Lymphoma (x40 risk), Neonate complete heart block (anti-Ro)
What is the prevalence of Sjogrens?
1-3%
Who is most likely to be affected by Sjogrens syndrome?
40-60 year old Females
How do you treat Sjogrens syndrome?
Eye drops, saliva replacement
Pilocarpine - for dry mouth (stimulates saliva production)
Hydroxychloroquine - anti-malarial and antinflammatory
Steroids and immunosupression
What are the 2 types of Systemic sclerosis?
Limited and Diffuse
What are the common symptoms of limited systemic sclerosis?
Calconosis - calcium deposits in the tissue
Raynaud’s
Eosophageal dysmotility
Sclerodactyly -localized tightening and thickening of skin on fingers and toes
Telangiectasia - small widened blood vessels of the skin
Pulmonary hypertension (in 30%)
What autoantibodies are associated with limited systemic sclerosis?
anti-centromere
What are the common symptoms of diffuse systemic sclerosis?
Truncal and acral skin involvement
Early organ involvement
Quicker and more severe than the limited disease in general
What is systemic sclerosis?
A multisystem autoimmune disease in which there is increased fibroblast activity resulting in abnormal growth of connective tissue, causing vascular damage and fibrosis.
What autoantibody is associated with Diffuse systemic sclerosis?
Anti-Scl-70
What are the GI manifestations of Systemic sclerosis?
Small bowel, oesophageal and rectal hypomobility
Pancreatic insufficiency
What are the Respiratory manifestations of Systemic sclerosis?
ILD
Pulmonary hypertension
Chest wall restriction
What are the Renal manifestations of Systemic sclerosis?
Hypertensive renal crisis
Ischaemic
What are the Cardio manifestations of Systemic sclerosis?
Raynaud’s with digital ulceration
Atherosclerotic disease
Hypertensive cardiomyopathy
Who is most likely to develop systemic sclerosis?
25-55 year old females
What can be used to treat systemic sclerosis?
CCbs Prostacyclin (Iloprost) ACEIs Prednisolone Immunosuppression Bosentan, Sildenafil
What are some of the major criteria for Mixed Connective tissue Disease (MCTD)?
Severe myositis Pulmonary involvement Raynauds Swollen hands Sclerodactyly Anti-U1-RNP
What are some of the minor criteria for MCTD?
Alopecia Leukopenia - low WBCs Anaemia Pleuritis Pericarditis Arthritis Malar rash Thrombocytopenia Mild myositis Histroy of swollen hands
What is Anti-phospholipid syndrome?
An AI disorder characterised by arterial and venous thrombosis, adverse pregnancy outcomes (for mother and fetus), and raised levels of antiphospholipid (aPL) antibodies
What are the Diagnostic criteria for Anti-phospholipid syndrome?
+ anti-cardiolipin antibodies/
lupus anticoagulant activity/
Anti-beta2-glycoprotein; on 2 occasions 12 weeks apart
Arterial/Venous thrombosis
Pregnancy loss with no other explanation (10-34/40)/
3 pregnancy losses with no other explanation (<34/40) due to eclampsia, severe pre-eclampsia or placental insufficiency
1 lab and 1 clinical to make diagnosis
What are the features of anti-phospholipid syndrome?
Superficial thrombophlebitis and livedo reticularis ( mottled reticulated vascular pattern)
Mild/Mod thrombocytopenia
Migraine
Libman-Sacks endocarditis
How is anti-phospholipid syndrome treated?
Thrombosis - lifelong anticoagulation
Pregnancy loss - aspirin + heparin during pregnancy
What are the 3 types of joint?
Synovial
Fibrous
Cartilaginous
Give an example of a fibrous joint
Bones in the skull
Give an example of a cartilaginous joint
Intervertebral discs
Give an example of a synovial joint
Knee
What is a simple synovial joint?
One pair of articular surfaces e.g. phalanges
What is a compound synovial joint?
More than one pair of articular surfaces e.g. elbow
What helps stabilise the joints during purposeful motion?
Shape of the bone
Ligaments
Synovial fluid
What helps lubricates the joints?
Cartilage interstitial fluid
Synovium-derived hyaluronic acid and lubrcin
What is synovial fluid absorbed and replenished by?
Synovial membrane
The synovial fluid has few cells, but what cells usually do exist in it?
Mononuclear leucocytes
What is needed for rapid movement of a joint to occur?
Decreased viscosity and increased elasticity of the synovial fluid
What are the main roles of articular cartilage?
Helps prevent joint wear and tear by allowing a low-friction surface
Distributes contact pressure to sunchondral bone
What is the ECM of articular cartilage made of?
Water (70%) - lubrication
Collagen (mainly type II) (20%) - strength
Proteoglycans (10%) - compression
What are the proteoglycans in cartilage made mainly of?
Glycosaminoglycan
Cartilage is 98% ECM, what is the other 2%, and what is its role?
Chondrocytes - synthesise, organise, degrade and maintain the ECM
Articular cartilage is avascular, so how does it receive its nutrients and oxygen?
Via the synovial fluid
With regards to the structure of cartilage, what can cause joint disease?
Changes in relative amounts of water, collagen and proteoglycans
ECM degredation exceeding rate of synthesis
What do catabolic factors do to cartilage matrix turnover?
Stimulate proteolytic enzymes and inhibit proteoglycan synthesis (TNF + IL-1)
What do anabolic factors do to cartilage matrix turnover?
Stimulate proteoglycan synthesis and counteracts the effects of IL-1 (TGF + IGF-1)
How can you tell if cartilage degradation is occuring?
Increased serum and synovial keratin sulphate levels
Type II collagen in the synovial fluid
What structural changes occur in an osteoarthritic knee?
Thickened joint capsule Cyst formation Subchondral sclerosis Fibrillated cartilage (softer with gaps) Synovial hypertrophy Osteophyte formation
What is seen microscopically in gout?
Deposition of needle shaped uric acid crystals
What is seen microscopically in psuedo-gout?
Deposition of rhomboid shaped calcium pyrophosphate crystals
What is the prevalence of RA?
1%
What genes are thought to be associated with RA?
HLA DR4 and DR1
What happens to the synovium in RA?
Macrophage, fibroblast and multi-nucleated giant cell infiltration
Membrane expands and erodes bone and cartilage
What are some symptoms of RA?
Morning stiffness
Malaise
Fatigue
Joint pain and swelling
How is RA classified?
Number and site of involved joints
Serological abnormality
Elevated acute phase response
Symptom duration
How can RA be investigated for?
Anti-CCP
RF
Inflammatory markers
What are the principles of RA treatment?
Early initiation of DMARDs with steroids to cover the lag phase
What biologic approaches have proved important in RA treatment?
Anti-TNF
B cell depletion
Disruption of T cell costimulation
IL-1 inhibition
What drugs target TNF inhibition in RA?
Inflximab
Adalimumab
Etanercept
What drugs target B cell depletion in RA?
Rituximab
What drugs target disruption of T cell costimulation if RA?
Abatacept
What drugs target IL-1 inhibition in RA?
Anankira
What is a motor unit?
A single alpha motor neuron and all the skeletal muscle fibres it innervates
When is calcium released from skeletal muscle fibres?
Surface AP spreads down transverse T tubules
What does the A band in a sarcomere contain?
Thick filaments, with the overlapping parts of the thin filaments
What does the H-zone in the sarcomere contain?
Middle of A bands where thin filaments dont reach
What is the M-line of a sarcomere?
It extends vertically down the middles of the A-band and the H-zone
What does the I-band of a sarocomere consist of?
Remaining portion of thin filaments that the A-band does not cover.
What are Z-lines?
Connect 2 sarcomeres
When is ATP required in the muscles?
Contraction and relaxation
When is caqlcium required in muscle movement?
Calcium binds the thin to thick filaments, allowing the process of contraction to begin
How does calcium switch on cross bridge formation?
It binds to troponin on actin, and the troponin-tropomyocin complex moves to uncover the cross bridge binding sites
Where is calcium released from in skeletal muscle movement?
Sarcoplasmic Reticulum
If AP duration is shorter than the muscle “twitch” associated with it, what does this mean in terms of muscle work?
Possible to summate twitches to bring about stronger contraction
How does tetanus in skeletal muscle occur?
If the fibres are stimulated so rapidly, that they do not have a chance to relax between stimuli.
Can cardiac muscle be tetanised?
No, the long refractory period prevents this occurring.
What is isotonic muscle contraction?
Body movements and moving objects.
Muscle tension is constant as length increases.
What is isometric muscle contraction?
Supporting objects in fixed positions and maintaining body posture.
Muscle tension changes whilst muscle remains the same length
What is the stretch reflex?
Negative feedback system that resists passive change in muscle length to maintain optimal resting length of muscle
What are muscle spindles?
A collection of specialised muscle fibres.
Where are muscle spindles found?
Within the belly of muscles, running parallel to the ordinary muscle fibres.
What are muscle spindles also known as?
Intrafusal fibres
What are ordinary muscle fibres also known as?
Extrafusal fibres
What are the sensory nerve endings of muscle spindles called?
Annulospiral fibres
What neurons will increase firing rate when a muscle is stretched?
Afferent neurons
What are the efferent neurons called that supply the muscle spindles?
Gamma motor neurons
What do gamma motor neurons do?
Adjust the level of tension in muscle spindles to maintain their sensitivity when the muscle shortens in contraction