Musculoskeletal Flashcards
(39 cards)
What are the pain pathways?
Pain perception is mediated by free nerve endings: nociceptors
A-delta fibres give rise to perception of sharp, immediate pain
C-fibres give rise to slower onset, prolonged pain
Sensory impulses enter the cord via the dorsal root and then ascend in the dorsal posterior column of the spinothalamic tract
What can pain lead to?
Multiple psychological effects
Leads to catecholamine release, with the resultant vasoconstriction leading to increased cardiac work and delayed healing
What is an overusuage/strain injuries presentation?
Exact time/mechanism of injury can be identified
Pain is non-progressive and produced by one/few moments
On examination there is localised tenderness and pain produced on resisted active movement/stress testing
What is osteoarthritis?
Most common type of osteoarthritis
Results from a disparity between the stress applied to articular cartilage and the ability of the cartilage to withstand that stress
Commonly affects the hip, knee, DIP, PIP, thumb CMJ and hallux MTP joints
Classically spares the MCPJs
What are the clinical features of OA?
Progressive pain: initial activity related to pain, then finally a constant rest pain
Stiffness: characteristically worse after periods of rest (gelling), but lasts <30 mins
Symptoms classically follow a waxing and waning course (good/bad days)
Later features are muscle wasting, loss of mobility, deformity and joint instability
What is seen on examination in OA?
Look: bony swelling, muscle wasting
Feel: joint line tenderness, possible effusion, crepitus
Move: limited range of movement
What are the risk factors for OA?
Age Obesity Family history: genetic predisposition Gender: polyarticular OA more common in women, particularly after menopause Hypermobility Previous trauma Occupation (miners, farmers) Protective factors: osteoporosis
What can secondary OA develop due to?
Pre-existing joint damage: inflammatory/septic/crystal arthritis, AVN, trauma
Metabolic disease: acromegaly, chonedrocalcinosis, haemochromatosis
Systemic disease: haemophilia (leading to haemarthroses)
What is hip OA?
More common in males, unilateral at presentation
Generally does poorly and requires arthroplasty
On examination: painful and decreased internal and external rotation of the hip
Positive Trendelenburg’s test (sound side sags)
What is knee OA?
Strong relationship with obesity, oath other risk factors being previous trauma or knee soft tissue injuries
Often bilateral and most commonly leads to genuflects various deformities due to medial disease
Classically on examination there will be a moderate effusion, decreased range of movement, crepitus and quadriceps wasting
What is nodal generalised OA?
Joints of the hands are affected one by one over many years, first presenting with painful swelling and impairment of function
Classically presents in menopausal women
Familial tendency, thought to have an autoimmune aetiology
What is affected in nodal generalised OA?
DIPs affected much more than PIPs and the inflammatory phase settles after months/years to have painless bony swellings posterolaterally
Herberdens (DIP) and Bouchard’s (PIPs) nodes
Function is generally still good
CMC and MCP joints of the thumb, bony swellings and fixed adduction leading to the classical ‘squared hand’ in OA
MCPJs are generally spared
Generally large joint involvement
What is erosive OA?
Rare with characteristic cysts seen on XR and a poor prognosis
What is crystal associated OA?
Calcium pyrophosphate deposition in the cartilage leads to chonedrocalcinosis (pseudo gout)
This can be asymptomatic or lead to the signs/symptoms of OA
Knees and wrists are most commonly affected
Who does rheumatoid arthritis affect?
Affects around 3% of women and 1% of men over their lifetimes
Pre-menopausal women affected more than men
No gender differences post-menopause
The disease is familial, yet inheritance is sporadic
What is the presentation of RA classically in 30-50 year old women?
Red, warm, painful and swollen peripheral joints, typically of the hands/feet
Then progresses to affect larger joints (still symmetrical)
This is worse in the morning, evolving over weeks/months
What occurs in 15% of people who present with OA?
There is a rapid onset of symptoms over days/overnight (better prognosis)
General malaise, weight loss and disturbed sleep is common
Extra-articular features may be present
What are rare presentations of RA?
Palindromic RA (recurring mono/poly arthritis), persistent mono-arthritis or systemic illness with extra-articular symptoms
What is the differential diagnosis of RA?
Includes reactive arthritis, seronegative spondyloarthropathies, polymyalgia rheumatica or acute nodal osteoarthritis
What are characteristic deformities in the hand in RA?
Ulnar deviation at the MCJPs
Radial deviation at the wrist
Boutonniere deformity: hyper flexed PIPJs, hyperextended DIPJs
Swan-neck deformity: hyper flexed DIPjs, hyperextended PIPJs
Z deformity in the thumb: flexed MCPJs, extension at IPJ
Subluxation is a late deformity: volar subluxation at the MCPJs/wrist
What can RA lead to in the hands?
Ankylosis (fusion) across the joint
Rupture of the little/ring finger extensor tendons can occur due to swelling and subluxation and this requires urgent surgical repair
Carpel tunnel syndrome is also very common due to inflamed tendon sheaths
What occurs in the feet in RA?
MPTJ swelling is one of the earliest manifestations
The foot becomes broader and a hammer-toe deformity develops
Ulcers/callouses can occur due to exposure of the metatarsal heads to pressure due to migration of the protective fat pad
What is large joint involvement in RA?
The knee is most commonly affected then the shoulder/hip
In the knee a genu valgus deformity and secondary OA can develop
Once severely affected, large joints require total replacement to restore function
How is RA diagnosed via blood tests?
FBC: leucocytosis and thrombocytosis in acute inflammatory phase, normocytic anaemia and chronic disease
CRP/ESR: elevated in active disease
Rheumatoid factor (RF): elevation in 70% but non-specific
Anti-CCP: more specific, rises predate clinical disease by several years
ANA: if suspecting connective tissue disease, however raised in 30%
Anti-nuclear antibody
