Locomotor Flashcards
What is osteoarthritis?
Disorder of synovial joints, which occurs when damage triggers repair processes leading to structural change within a joint (progressive and degenerative joint disorder)
What are the most commonly affected joints by osteoarthritis?
knees, hips, hands
Which cells are involved in the breakdown of cartilage seen in osteoarthritis?
Chrondrocytes
How are chondrocytes involved in osteoarthritis?
Over time, continuous ‘wear’/trauma to joint causes local inflammation and stimulation of chondrocytes to release degradative enzymes
These enzymes break down collagen and proteoglycan; destroys articular cartilage
When the articular cartilage is destroyed by chondrocytes in osteoarthritis, what is exposed?
Subchrondral bone
How does the exposure of subchondral bone play a role in osteoarthritis?
Over time, cartilage thins which leads to exposure of subchondral bone which causes subchondral sclerosis
Continuous remodelling of subchondral bone forms subchondral cysts and osteophytes → leads to loss of joint space
Risk factors for osteoarthritis?
- Increasing age
- Female sex
- Obesity
- Articular congenital deformities/trauma to joint (less common)
What are the 3 criteria required for a diagnosis of osteoarthritis?
- >/= 45 y/o AND;
- Has activity related joint pain AND;
- Has either no morning related joint stiffness or morning stiffness that lasts no longer than 30 minutes
How does movement affect pain in OA vs inflammatory arthritis?
OA → worse on movement
Inflammatory → pain tends to improve on movement
Describe morning stiffness in OA vs inflammatory arthritis
OA → not prolonged (usually <20 minutes)
Inflammatory → morning stiffness is prolonged (>30 minutes)
Give some signs seen in OA
- Reduced active and passive range of movement (2ary to pain)
- May have a fixed deformity
- Joint swelling but it shouldn’t be particularly hot or red
- Tenderness over joint lines
- Crepitus on movement
- Cervical lordosis
- Joint effusion (patellar tap)
Give some signs seen in the hands in OA
- Sparing of MCP joints
- Bony enlargement of PIP joints → Bouchard’s nodes
- Bony enlargement of DIP joints → Heberden’s nodes
- Squaring of 1st carpometacarpal joint (base of thumb)
- Reduced functional movement (e.g. reduced grip strength)
Which joints in the hand are typically spared in OA?
MCP joints
Describe inflammatory markers in OA
CRP/ESR are typically normal in osteoarthritis
What is 1st line imaging in OA?
xray
Give the 4 typical signs seen on an xray in OA
- Loss of joint space
- Osteophytes
- Subchondral sclerosis
- Subchondral cysts
Conservative management for OA?
- Education and advice about condition
- Exercise: muscle strengthening and general aerobic fitness
- Avoid weight bearing exercise though as can accelerate progression of disease
- Weight loss (if overweight/obese)
Give the stepwise analgesic management of OA
- 1st line: Topical NSAIDs (particularly effective for pain from OA)
- 2nd line: Paracetamol and topical NSAID
- 3rd line: Oral NSAID, paracetamol and topical capsaicin
- 4th line: Opioid, NSAID, paracetamol and topical capsaicin
- Intra-articular corticosteroid injection can be offered for acute exacerbation of pain (consists of steroid and local anaesthetic)
What is arthroplasty?
Joint replacement
What is athrodesis?
Fusion of joint
What is the analgesic ladder?
- Step 1 → Non-opioid analgesics e.g. NSAIDs +/- adjuvant therapy
- Step 2 → Weak opioids (hydrocodone, codeine, tramadol) +/- non-opioid analgesics +/- adjuvant therapy
- Step 3 → Potent opioids (morphine, methadone, fentanyl, oxycodone, buprenorphine, tapentadol, hydromorphone, oxymorphone) +/- non-opioid analgesics +/- adjuvant therapy
What is gout?
A disorder of purine metabolism characterised by raised uric acid levels in the blood (hyperuricaemia) and the deposition of monosodium urate crystals in joints and other tissues.
What are tophi?
Deposits of monosodium urate crystals in the skin in people with longstanding hyperuricaemia
What are tophi pathognomonic for?
Gout
What is the most common inflammatory arthritis?
Gout
Prevalence of gout in developed vs less developed countries?
Developed countries have much higher prevalence than less developed countries
What is the single most important risk factor for gout?
Hyperuricaemia
Give some non-modifiable risk factors for gout
- Male gender
- FH of gout
- Increasing age (>50 y/o) – Gout in <30 y/o suggests renal/enzymatic disorders (genetic)
Give some modifiable risk factors for gout
- Obesity
- Hypertension
- Diabetes
- CKD
- Metabolic syndrome
- Medications – thiazide diuretics, ACEi and aspirin
- Alcohol
- Menopause
- Dyslipidaemia
What medications can cause gout?
Thiazide diuretics, ACEi and aspirin → all raise uric acid levels
The triggering of acute gout flares is often due to what?
Increased production of uric acid, either through digestion of protein or increased cell turnover and protein degradation:
- Seafood & organ meats/protein binges – eating lots of high protein food raises levels of uric acid
- Chemotherapy – increases cell breakdown
- Trauma & surgery – increases cell breakdown
Pathophysiology of gout?
Precipitation of uric acid crystals within the joint leading to an acute inflammatory response.
Is it more common for gout to be caused by an under excretion of urate or an over production of urate?
- 90% under-excretors of urate
- 10% over-producers of urate
What conditions is gout seen more commonly in?
- Hyperparathyroidism
- Down’s syndrome
- Sarcoidosis
- Chronic renal disease
- Severe psoriasis
- Hypertension
3 most common gout complications?
- Kidney damage
- Joint damage
- Bone loss
What are the 3 most important differentials of monoarthropathy?
- Septic arthritis
- Crystal arthropathy – gout/pseudogout (non-urate crystal-induced arthropathy)
- Inflammatory arthritis – rheumatoid arthritis, seronegative arthritis
What is pseudogout?
Pseudogout → non-urate crystal-induced arthropathy
What should be excluded in any patient presenting with a hot swollen joint, especially if they are systemically unwell?
Septic arthritis
Which joint is typically affected in acute attacks of gout?
1st MTP joint (big toe
What characterises acute gout attacks?
- Sudden, severe attacks of pain, swelling, redness and tenderness in the joint
- Asymmetric joint distribution
Signs seen in acute gout attack?
- Arthritis (swelling, redness, warmth, and pain on passive movement) typically of 1st MTP joint (although any joint can be affected)
- Tophi (white lumps under skin formed from urate crystals)
- Tachycardia as a transient sympathetic response to the pain of an acute attack
1st line investigation in gout?
(Note - investigations are usually not performed in typical gout presentation)
Arthrocentesis with synovial fluid aspiration
What result of the arthrocentesis would confirm a gout diagnosis?
Needle shaped monosodium urate crystals with negative birefringence confirm gout and differentiate it from pseudogout
In arthrocentesis in suspected gout, why should fluid be sent for gram stain and culture?
To rule out septic arthritis
A serum uric acid can be measured in gout to confirm hyperuricaemia. When should this be done?
Measured at least 2 weeks after acute attack
N.B. gout can develop with serum uric acid levels within the normal range
Describe joint space in gout xray
Normal
Give the 1st line NSAID used in the pharmacological management of gout?
Indomethacin
Is aspirin indicated in gout?
no → contraindicated as reduces uric acid excretion
Why is aspirin contraindicated in gout?
Do not use aspirin, because it can alter uric acid levels and potentially prolong and intensify an acute attack.