Phase 2 - MSK Flashcards
Define Osteoarthritis
An AGE related, DYNAMIC REACTION PATTERN of a joint in response to INSULT and INJURY - also has a genetic component
(aka NON-INFLAM DEGENERATIVE MECHANINCAL SHEARING OF JOINTS, usually age related)
- All tissues of joint involved but esp ARTICULAR CARTILAGE
- Changes in underlying bone at joint margin
Multifactorial in origin
Subtypes of osteoarthritis
- Nodal OA - strong genetic component
- Inflammatory/erosive OA
- Hip OA
- Knee OA
OA Staging
1 = doubtful = ~10% cartilage loss
2 - osteophyte development starts (looks like little bony outpouchings)
3 - increased loss of joint space + osteophytes
4 - severe
Epidemiology of OA
- Most common condition affecting synovial joints
- Most important condition relating to disability as result of locomotor symptoms
- 8.75 million people in the UK have sought treatment for OA
Impact to UK economy ~1% GNP (2008):
- Lost days of work
- Incapacity benefit
- Treatment strategies
Causes/risk factors of OA
- AGE (cumulative effect + decline in neuromuscular function) - esp >50 y/o
- FEMALE (post menopause)
- GENETIC predisposition - esp if POLYARTICULAR (COL2A1)
- OBESITY
- thought to be due to the low grade inflam state
- release of IL1, TNF, ADIPOKINES (Leptin. adiponectin)
- Occupation
- manual labour - small hand joints
- farming hips
- football - knees
Others:
- Direct trauma
- Inflam arthritis
- Abnormal biomechanics (e.g. congenital hip dysplasia, hypermobility, NEUROPATHIC CONDITIONS)
Percentage of people over 65 with osteoarthritis
80-90% over 65 will have radiographic evidence of OA and 50% will have symptoms
Pathophysiology of osteoarthritis
Characterised by:
- LOSS OF CARTILAGE due to shift in homeostatic balance of tissue (i.e. imbalance between the cartilage being worn down and the chondrocytes repairing so net loss)
- Matrix metalloproteinases increase -> collagen degradation + cyst formation -> increased mechanical wear -> stiffness + pain
- Nitric oxide further activates metalloproteinases
- DISORDERED BONE REPAIR (attemt to overcome via T1 collagen -> formation of osteophytes)
A METABOLICALLY ACTIVE + DYNAMIC PROCESS - mediated by CYTOKINES:
- IL-1
- TNFa
- NO
and DRIVEN BY MECHANICAL FORCES
SIgns + symptoms of OA
- PAIN (may not be present despite radiographic change)
- Transient Morning stiffness <1 hr (some say < 30 mins)
- stiffness gets worse over course of day/with more activity
- FUNCTIONAL IMPAIRMENT:
- Walking
- Activities of daily living
- Inability to do stuff -> muscle wasting -> make things worse
Signs:
- Altered GAIT
- JOINT SWELLING (usually asymmetrical, hard + non-inflamed)
- Bony enlargement
- Heberden’s (DIP) and Bouchard’s (PIP) nodes + esp used joints 1st MCP, MTP, hip/knees(in nodal)
- Effusion
- Synovitis (if inflammatory component)
- Bony enlargement
- Limited range of motion
- Crepitus (crackling noises - esp in patellar OA)
- Tenderness
- Deformities
No extra-articular presentation
Investigations for OA
X-RAY - remember findings as JOSSA (like bone fossa)
- Joint space narrowing
- Osteophyte formation
- Sub-chondral sclerosis
- Sub-chondral cysts
- Abnormalities of bone contour
Bloods normal
Diff diagnosis OA
Rheumatoid or Reactive Arthritis
Non-medical management of OA
- Patient education/support
- Activity/exercise
- Weight loss (can be a pre-requisite for surgery)
- Physiotherapy
- Occupational therapy
Weight bearing supports:
- Footwear/orthoses (can get wedge to improve weight bearing)
- Walking aids: stick, frame
- Splints
Pharm treatments of OA
Pain killers/anti-inflam
Topical
- NSAIDs
- Capsaicin cream
Oral
- Paracetamol
- NSAIDs (with caution - may be paired with PPIs)
- Opioids (don’t work for chronic pain -> addiction)
Transdermal patches
- Buprenorphine (strong opiod)
- Lignocaine (local anaesthetic + antiarrhythmic)
Intra-articular steroid injections (not disease modifying and then get steroid side effects so not as commonly used if avoidable)
DMARDs for inflam OA
Surgical treatment of OA
- Arthroscopy (only indicated for loose bodies)
- camera into joint
- Osteotomy (partial removal of bone)
- Arthoplasty (complete replacement)
- will eventually have to be replaced
- Fusion of bones (if joint won’t tolerate replacement well e.g. ankle/foot)
- stops pain but loss of mobility
Indications for Arthoplasty
- Significant/uncontrolled pain (esp at night)
- Sig loss of function
It may be discouraged in youger patients as they will inevitably need replacement
Complication of OA
- pain, loss of function etc.
- Loose bodies (bone/cartilage fragment) can get stuck within joints and can cause the joint to ‘lock’
- esp in KNEE
- only indication of ARTHROSCOPY in OA
Presentation of Nodal OA
- affects hands -> reduced function
- Heberden’s (DIP) and Bouchard’s (PIP) nodes
- MCP esp of thumb affected
- Initial inflam phase
- BONY SWELLINGS + CYSTS
- Relapse/remit over a few years
Presentation of Knee OA
- Can affect 3 compartments (in isolation or a combination of these):
- Medial (mc)
- Lateral
- Patellofemoral (request more views when imaging)
- Slow evolution if no significant trauma
- Oft stays stable for years once established (unless there is trauma)
Presentation of Hip OA
- Pain in groin - may persist at night and wake people up
- Difficulty walking
Presentation of Erosive/Inflam OA
- Erosive element - can look like birds wings on scan
- Inflammatory component
- DMARD therapy oft used (ususally milder things like hydroxychloroquine)
When can a clinical diagnosis of OA be made without investigation
If patient is:
- Over 45
- Has typical activity related joint pain
- No morning stiffness or morning stiffness that lasts less than 30 minutes
Advice to give regarding a prescription of alendronate
- Take first thin in morning
- On an empty stomach
- Remain upright 30 mins after taking
Define fibromyalgia
A chronic pain syndrome diagnosed by presence of widespread MSK pain lasting >3 MONTHS with all other causes ruled out
DDx of Fibromyalgia
Polymyalgia Rheumatica also presents with widespread pain, more common in females
- but presents almost exclusively OVER 50 Y/O
- Also has raised ESR/CRP
Risk factors of Fibromyalgia
- FEMALE
- Poor socieconomic status
- Depression/stress
- 20-50 Y/O