MSK Flashcards
What lab findings are associated with pseudo gout?
Hypothyroidism, hyperparathyroidism, haemochromatosis, hypomagnesaemia
What is compartment syndrome?
Elevated interstitial pressure in a closed fascial compartment leading to microvascular compromise.
(usually 0-4mmHg but may be > 30mmHg)
What is the pathophysiology of compartment syndrome?
Internal or External compression
Pressure in the compartment exceeds capillary pressure and so blood flow is reduced. Venous blood flow is affected first. Arterial inflow continues.
Pressure increases due to endothelial calls becoming more permeable and so oedema- more swelling
Arterial flow is reduced - hypoxia – muscle swelling
Autoregulatory mechanisms overwhelmed.
Necrosis after 4 hours of ischaemia
List some features and causes of mechanical back pain.
Morning stiffness < 30min
Pain worse with movement and prolonged standing
- Lumbar sprin/strain
- Degenerative disc disease (spondylosis)
- Spinal Stenosis, disc prolapse
- Compression fractures
Give an example of a type of back pain that is an emergency.
Cauda equina syndrome
Bilateral sciatica, saddle anaesthesia, bowel and bladder dysfunction (reduced anal tone), numb around genitals and anus
What primary cancers can metastasise and cause non-specific back pain?
LP Thomas Know Best
Lung, Prostate, Thyroid, Kidney breast
Give some red flags of back pain.
New onset <16 or >50 Following trauma Previous malignancy HIV, IVDU, Immunocompromised Urinary retention Recent significant infection Saddle anaesthesia, anal tone reduced, hip or knee weakness
What is the criteria for axial Ankylosing spondylitis?
Chronic back pain (>3 months) and age onset < 45
AND
Scaroilitis on imaging + >/= 1 feature OR
HLA B27 + >/= 2 features
(uveitis, inflammatory back pain, arthritis, IBD, enthesitis, family history, psoriasis, dactylitis)
What is Ankylosing spondylitis?
A chronic inflammatory rheumatic disease of the spine and sacroiliac joints of unknown aetiology.
HLA B27
3M:F
What examinations can you use in the diagnosis of Ankylosing spondylitis?
Schobers- detects reduced flexion >20cm is normal
Flesches - Occipit to wall distance (should be 0)
What is the commonest cause of progressive spastic quadriparesis and sensory loss below the neck?
Cervical spondylosis with spinal cord compression (myelopathy) and nerve root compression
What is L’Hermitte’s symptom?
Sudden transient electric like shock extending down the spine triggered by flexion of the neck
What is Pagets disease of the bone?
AKA osteitis deformans
Metabolic disorder of the bone
Increased bone turn over due to increased osteoclast and osteoblast activity. More osteoclasts and have more nuclei (100 compared to 3-10) Weak woven bone laid down - bone enlargement, bone deformities, weakness
What are some complications of pagets disease?
Neurological: Hearing loss, spinal stenosis, nerve root compression
Ortho: Osteoarthritis, pathological fractures
Oncological: osteosarcoma, giant cell tumours
Other: Hyperclacaemia, 2ndary hyperparathyroidism, HF
What treatment is available for pagets disease of the bone?
Analgesia
Zolendronate 5mg IV single infusion
Ca / Vit D supplements
What are the subtypes of psoriatic arthritis?
DR SAM
DIP joint disease
Rheumatoid like pattern (symmetrical polyarthritis)
Spondyloarthritis
Asymmetrical oligoarthritis/ monoarthritis (50%)
Mutalins (arthritis mutalins)
What is the severe form of psoriatic arthritis?
Arthritis Mutilans
Occurs in phalanxes
Osteolysis around the bone of the joints leading to shortening of the digits. The skin then folds in as the fingers shorted - Telescope fingers
How might osteonecrosis cause arthritis?
Reduced blood supply to the bone - Ischaemia - necrosis
Dead bone can’t remodel
No remodelling leads to microdamage
Damage accumulates and the bone weakened and collapses
Irregular surface causes more damage
What are some risk factors for osteonecrosis?
History of trauma, Corticosteroid use or cushings disease, alcohol abuse, sickle cell disease/ haemoglobinopathies, renal failure, HIV, Bisphosphonates (AVN of the jaw), SLE, anti-phospholipid syndrome
What is myasthenia gravis?
An autoimmune condition causing muscle weakness. Progressively gets worse with activity and better with rest. 85% Anti-Ach Receptor antibodies.
What condition is linked to myasthenia gravis?
Thymoma
What antibodies can be found in Myasthenia Gravis?
Acetylcholine receptor antibodies
Muscle specific kinase
Low density lipoprotein receptor related protein 4 (LPR4)
List some symptoms of myasthenia gravis.
Weakness that is worse with muscle use and improve with rest Worst at the end of the day Extraocular muscle weakness - diplopia Eye lid weakness - ptosis Facial muscle weakness Difficulty swallowing Slurred speech Jaw fatigue
What is Polymyalgia rheumatic?
A chronic systemic rheumatic inflammatory condition causing pain and stiffness to the shoulders, neck and pelvic girdle. Usually in association with giant cell arteritis
What is Rheumatoid arthritis?
A inflammatory disorder characterised by symmetrical polyarticular arthritis usually involving the hands, follows a chronic course and can result in disability
3F:M, 30-60y
What is Osteoarthritis?
A degenerative disease of the joints that affects all weight bearing components of the joint
What are the X-ray features of Osteoarthritis?
LOSS Loss of joint space Osteophytes Subchondral sclerosis Subchondral Cysts
What are the stages of OA on X-ray?
Stage 1: Doubtful JSN and possible osteophyte lipping
2: Definite osteophytes and possible JSN
3: Multiple Osteophytes, sclerosis, definite JSN and possible deformity
4: Large osteophytes, severe sclerosis, markedJSN, definite bony deformity
If a arthritis is seronegative for rheumatoid factor what will it show?
HLA-B27
What commonly causes the inflammatory cause for back pain, infective discitis?
Staphylococcus aureus
PUO, weight loss, constant back pain (at rest and night pain)
Immunosuppressed, diabetic, IVDU
What are the 2 criteria for diagnosing ankylosing spondylitis?
New York criteria AS
ASAS criteria for axial SpA
Describe the New York criteria for diagnosing AS.
Clinical criteria
- Lower back pain and stiffness for > 3 months, improved with exercise but not relieved with rest
- Limited lumbar motion
- Limited chest expansion
Radiological criteria
- Sacroilitis Grade >/=2 bilaterally or Grade 3-4 unilaterally
Radiological criteria with at least 1 clinical
Describe the ASAS criteria for axial SpA.
In patients with > 3 months back pain age onset < 45
Either - Sacrolitis on imaging** + >/=1 SpA feature
OR HLA- B27 + >/= 2 SpA feature
SpA features - Arthritis, inflam back pain, uveitis, psoriasis, Enthesitis, dactulitis, crohns/colitis, elevated CRP, HLA-B27
** Active inflam pn MRI highly suggestive or definite according to New York criteria
What extra-articular features may be seen in AS?
Males < 30
Enthesitis - achilles tendonitis, plantar fasciitis
Arthritis
Atlanto-axial subluxation - neck hyperextension
Anterior uveitis
AV node block
Amyloidosis
Anterior mechanical chest pain due to costochondritis
Apical lung fibrosis
In AS, what may be seen on X-ray?
Sacroilitiis - in lower half of joint in early stages
*Vertebral syndesmophytes - Often T11-L1 - bony proliferations due to enthesitis between ligaments and bone. these fuse with bone - ankylosis. Ligament calcifies - bamboo spine.
Also can do MRI to look for bone marrow oedema in sacroiliac joint
What tests can u do for AS?
Flesches - occiput to wall distance - Severity of cervical flexion deformity
Schobers test - reduced flexion in lumbar spine
How might you manage a pt with ASpod?
- Exercises and staying active to maintain posture and mobility
- NSAIDs - Diclofenac, naproxen
- TNF-alpha inhibitors - Adalimumab, golimumab
- DMARDs - cDMARDs (methotrexate, sulphasalazine - Used for peripheral arthropathy), bDMARDs (if NSAIDs + PT failed)
- Cox-2 inhibitors - celecoxib, etorcoxib
What is cervical spondylosis?
Most common cause of progressive spastic quadraparesis and sensory loss below the neck
As the neck flexes and extends the cord is dragged anteriorly across the bony spurs (osteophytes) and indented by a thickened ligament flavum posteriorly
What symptoms and signs may be seen in cervical spondylosis?
Axial neck pain/ neck stiffness Crepitus with neck movement L'hermitte's sign Radiculopathy Foot drop, weak clumsy hands, heavy legs, incontinence §
How might you distinguish between C6 radiculopathy and carpal tunnel syndrome?
Spurlings manoeuvre can exacerbate C6 radiculopathy
CTS - thenar atrophy, weakness in wrist flexion
C6 - elbow flexion and wrist extension weakness
Give some examples of cancers causing bone mets that are sclerotic or lytic? (give causes for each)
Lytic - Renal and thyroid (lytic more common)
Sclerotic - prostate, breast, carcinoid
What are some complications of the metabolic bone disease pagets disease of the bone?
Osteosarcoma, Spinal stenosis - spinal cord compression, Hight output CCF
Hearing loss, OA, pathological f#, hypercalcaemia, 2ndary hyperparathyroidism
How would you monitor disease progression in Pagets disease of the bone?
ALP
Tx - bisphosphonates, analgesia, Ca and vir D supplements, PT, OT
What condition is linked with MG?
Thymoma - do a CT thymus
What autoantibodies are seen in MG?
ACh receptor antibodies 85%
Muscle specific kinase (MuSK) 10%
Low density lipoprotein receptor related protein 4 (LRP4)
What is MG and what are some symptoms?
An autoimmune condition in which ACh receptor antibodies block the transmission of NT leading to muscles weakness. Fatiguability of muscles * worse at the end of the day.
First Sx - Extraocular muscles - Ptosis, diplopia
Fatiguability while chewing, problems swallowing, slurred speech
Affects proximal muscles and small muscles of head and neck
What examinations can you do to test for MG?
Repeated blinking - fatiguability of eyelids - ptosis
Prolonged upward gaze - diplopia
20 Abductions at shoulder - unilateral weakness
Thymectomy scar? FVC
IV endrophonium test - Give IV endrophonium chloride or neostigmine - should inc ACh in cleft - briefly relieves weakness
What is a myasthenic crisis?
Severe life threatening complication
Triggered by another illness
Respiratory failure due to weakness in respiratory muscles - NIV, BiPAP, ventilated and intubated? IVIg, plasma exchange
What is polymyalgia rheumatica?
A chronic, systemic, inflammatory, rheumatic disease causing pain and stiffness around the neck, shoulders and pelvic girdle **
What condition is often associated with PMR?
Giant cell arteritis
What are the core features of PMR?
Morning stiffness >45 min
Bilateral shoulder pain and stiffness that goes down to the elbow lasting >/=2 weeks (difficult brushing hair)
Bilateral Pelvic girdle pain or stiffness lasting >/=2 weeks (difficult getting up from a chair)
Symptoms worse with movement and interfere with sleep
How might you manage a patient with suspected PMR?
Rapid improvement with low dose steroids
15mg Prednisolone daily
Assess after 1 week - working?
3-4 weeks - 70% improvement? reduced inflam markers? start reducing dose to wean off
How would you investigate for gout?
Serum uric acid level
Polarised light microscopy - joint aspiration
X-ray
What can cause hight levels of uric acid?
Obesity, old age, excess alcohol, high protein diet
Genetic predisposition - Lesch-nyhan syndrome
Secondary - myeloproliferative disease, CKD, leukaemia treated with chemo, diuretics
How could you tell gout and pseudo gout apart?
Gout - Urate crystals. High serum uric acid. Yellow needle shaped Negative birefringence in polarised light, TOE, severe sudden onset pain
Pseudogout - Calcium pyrophosphate crystals. Sr uric acid normal, blue rhomboid Positive birefringence crystals, KNEE, moderate pain, Chondrocalcinosis
What screening tool can be used in psoriasis / psoriatic arthritis?
PEST - Psoriasis epidemiological screening tool
How would you manage a patient with psoriatic arthritis?
- Lifestyle changes and NSAIDs
- cDMARDs - methotrexate, sulphasalazine
- Anti-TNF - Entanercept, infliximab, adalimumab
- Biologics - UStekinumab - IL12/23
What X-ray features may be seen in osteonecrosis?
Crescent sign, subchondral collapse, bone remodelling
What Lab investigations might you do in suspected RA?
ESR/CRP, LFTs, FBC
Rheumatoid factor - IgM directed against IgG
Anti-cyclic citrullinated peptide antibody, inflammation leads to cellular damage, citrullination of arginine into citrilline - foreign so ab created
In RA, cDMARDs are first line, the if failed on >/=2 bDMARDs, what must you do before commencing bDMARDs?
Screening for: Viral hepatitis, TB, VZV
Contraindicated in - TB, infection, pregnancy, malignancy, diverticular disease
What scoring systems may be used to predict the 10year risk of a fragility fracture?
FRAX - ± DEXA bone mineral density
QFracture - doesn’t use BMD
Age, BMI, alcohol, smoking, FH, co-morbidities
What is the T score and Z score?
T score is how many standard deviations above or below the mean your BMD is compared to a young healthy Caucasian adult.
Z score is compared to someone your age
First line for osteoporosis is bisphosphonates, what is their MoA and SE?
Aldendronate Once weekly PO
Risedronate once weekly PO
Zolendronic acid once year.y IV
Reduce bone turnover by inhibiting osteocalats. It is readily incoroporated into bone (hydroxyapatite bonding site), when osteoclasts try resorb it, it accumulates. their activity is inhibited and they undergo apoptosis.
SE - oesophagitis, atypical femoral f#, avascular necrosis of the jaw
What Rules are there for taking bisphosphonates?
- Take first thing in the morning, before breakfast and any other tabkets
- Take with lots of water
- Sit upright for 30min and do not drink or eat in this time
- Avoid other Ca supplements or things with Ca in them (or wait 4 hours until taking as it impairs absorption)
