Musculoskeletal & Rheumatology Flashcards
What are the features of inflammatory pain?
Inflammatory :
- pain eases with use
- stiffness, >30 mins in morning
- swelling, synovial +/- bony
- hot + red
- young
- joint distributions = hangs and feets
- responds to NSAIDs
What are the features of degenerative pain?
- pain increases with use
- stiffness, not prolonged
- swelling, none, bony
- not clinically inflamed
- older people
- joint distribution = 1st CMC J, DIP J, knees
- less convincing response to NSAIDs
What are the patterns of bone pain?
pain at rest and night
- tumour, infection, fracture
What are the patterns of pain in inflammatory joint pain?
Pain and stiffness in joints in the morning, at rest and with us
What are the patterns of pain in osteoarthritits?
pain on use,
at end of day
What are the patterns of pain in neuralgic?
Pain + paraesthesia in dermatomal distribution worsened by specific activity
What are the patterns of pain in referred pain?
Pain unaffected by local movement
Define osteomyelitis.
Bone - marrow - inflammation
- infection localized to bone
What is the epidemiology of osteomyelitis?
- increasing incidence of chronic osteomyelitis
- bimodal age distribution
young = haematogenous osteomyelitis
older = diabetes, peripheral vascular disease
What are the 3 pathways in osteomyelitis of pathogens infecting the bones?
bacteria gets into the bone by:
1) direct innoculation into the bone = wound, trauma, surgery
2) continugous spread of infection to bone = spreads to adjacent soft tissue and joints, older adults, DM
3) Haematogenous seeding = pathogen in one part of the bone carried via blood to another weal part, children, mono-microbial
What host factors are risk factors for osteomyelitis?
Behavioral factors
i.e. risk of trauma
Vascular supply
Arterial disease
Diabetes mellitus
Sickle cell disease
Pre-existing bone / joint problem
Inflammatory arthritis
Prosthetic material inc arthroplasty
Immune deficiency
Immunosuppressive drugs
Primary immunodeficiency
What bones are most likely affected in Osteomyelitis?
Adults = vertebra - clavicle, pelvis
Children = long bones
Why in adults is osteomyelitis more likely to affect vertebra?
With age the vertebrae become more vascular, making bacterial seeding of the vertebral endplate more likely
Why are long bones in children more likely to be affected in osteomyelitis?
In metaphysis
- blood flow is slower
- endothelial basement membranes are absent
- The capillaries lack or have inactive phagocytic lining cells
- High blood flow in developing bones in children
Which other groups of people have a higher risk of getting osteomyelitis?
- People who inject drugs (PWD / IVDU)
younger, more often clavicle and pelvis - People with risk factors for bacteremia
central lines, on dialysis
sickle cell disease,
urinary tract infection, urethral catheterization
Similar factors as those for infective endocarditis
What are steps of the pathogenesis of osteomyelitis?
- inflammatory exudate in the marrow
- increased intramedullary pressure
- extension of exudate into the bone cortex
- rupture through the periosteum
- interruption of periosteal blood supply causing necrosis
- leaves pieces of separated dead bone
- new bone forms here
What is the acute phase of osteomyelitis?
Bacteria reach the bone and start to proliferate. This alerts immune cells and they try and fight off the infection.
The immune cells release chemicals that cause local bone destruction and usually this is effective
What is chronic osteomyelitis?
If the lesion is not that extensive, and there’s viable bone the osteoblasts and the osteoclasts begin to repair the damage over a period of weeks.
However, in some cases, the process turns into a chronic osteomyelitis - lasting months to years.
What are the signs of osteomyelitis?
Systemic:
Fever, rigors, sweats, malaise
Local:
tenderness, warmth, erythema, and swelling
PLUS any of
draining sinus tract
deep / large ulcers that fail to heal despite several weeks treatment*
non-healing fractures
What are the symptoms of osteomyelitis?
Onset - several days.
dull pain at site of OM
- may be aggravated by movement.
fever
erythema
muscle aches
What are the investigations for osteomyelitis?
Laboratory tests:
Acute = high WCC
Chronic = can have normal WCC
Raised inflammatory markers = CRP but can be normal
Imaging:
plain radiographs
MRI
CT (alternative to MRI)
Nuclear Bone scan if metalwork makes CT/MRI impossible
What is the gold standard test for osteomyelitis?
MRI- will show bone marrow oedema and abscesses
When can you use an X-ray as an investigation osteomyelitis?
in chronic osteomyelitis
What can be identified in an MRI for osteomyelitis?
- bone marrow oedema from 3-5 days
- Delineates cortical, bone marrow and soft tissue inflammation
What are the diagnosis differentials in OM?
Soft tissue infection (Cellulitis and erysipelas)
Charcot joint
Avascular necrosis of bone = Causes: steroid, radiation, or bisphosphonate use.
Gout = uric acid crystals in joint fluid / more acute presentation
Fracture
Bursitis
Malignancy
What is the treatment for osteomyelitis?
- 6 weeks of flucloxacillin, possibly with rifampicin or fusidic acid added for the first 2 weeks
- Clindamycin if penicillin allergy
- Vancomycin in MRSA
Chronic requires 3 months of antibiotics
What are the more radical treatments for osteomyelitis?
- Surgical
Debridement
Hardware placement or removal - Antimicrobial therapy
Initial broad spectrum empirical therapy “start SMART”
- S. aureus or MRSA?
- gram-negative organisms?
- Special population: IVDU/HbSS?
Tailored to culture and sensitivity findings -
- “then FOCUS”.
Bone penetration of drug
Prolonged duration
- unreliable antibiotic penetration into bone if vascular disease
- shorter duration possible if all infected bone resected
What are the features and managment of TB osteomyelitis?
- May be slower onset
- Systemic symptoms
- Epidemiology is different from pyogenic OM
- Blood Culture less useful
- Biopsy essential:
prolonged mycobacterial culture
Caseating Granolumata on histology
Induced sputum may help (sometimes occult pulmonary TB) - Longer treatment 6 months (oral instead of IV)
What are the usual microrganisms that cause OM?
Staphylococcus aureus,
coagulase-negative staphylococci,
aerobic gram-negative bacilli (30%)
Others:
Streptococci (skin, oral)
Enterococci (bladder, bowel)
Anaerobes (bowel)
fungi,
Mycobacterium tuberculosis
What acute and chronic changes occur in the histopathology of OM?
Acute changes:
Inflammatory cells
Oedema
Vascular congestion
Small vessel thrombosis
Chronic changes:
neutrophil exudates
lymphocytes & histiocytes
Necrotic bone ‘sequestra’
new bone formation ‘involucrum’
What are the clinical features for OM in hip, vertebra or pelvis?
pain but few other signs
What are the clinical features for OM in Vertebral: lumbar > thoracic > cervical?
- Posterior extension - epidural and subdural abscesses or even meningitis.
- Extension anteriorly or laterally can lead to paravertebral, retropharyngeal, mediastinal, subphrenic, retroperitoneal, or psoas abscesses
What are the clinical features for OM in joints?
(can also present as septic arthritis.)
when infection breaks through cortex resulting in discharge of pus into the joint (knee, hip, and shoulder).
More common in infants due to patent transphyseal blood vessels and immature growth plate
What are the complications of osteomyelitis?
Septic arthritis - if infection spreads to joints
Growth disturbance in children and adolescents
Amputations
What is the most common microorganism to cause joint infection?
staphylococcus aureus
What happens to prednisolone dose on being admitted into hospital with an infected joint?
double the dose
What is septic arthritis?
An infection of 1 or more joints caused by pathogenic inoculation of microbes.
(infection within a joint)
What is the epidemiology of septic arthirits?
- 2-8 cases in 100,000
more common in Rheumatoid arthritis
M =F
prosthetic joint infection > native joint infection
What is gonoccocal arthiritis?
- joint inflammation occurs within disseminated gonococcal infection
- affects multiple joints = polyarticular compared to septic
- maculopapular = pustular rash
What are the risk factors for a septic joint?
Any cause for bacteraemia
Direct/ penetrating trauma
Local skin breaks/ ulcers
Damaged joints/ undelrying joint disease
IV drug user
prosthetic joint
Immunosuppression (including steroids only)
Elderly
Rheumatoid arthritis (or other immune-driven disease)
Diabetes
What are the typical clinical presentations of septic joints?
Painful, red, swollen, hot joint
Remember children may just not use it
Fever
90% monoarthritis (So don’t rule out in polyarticular presentations)
Knee > hip > shoulder
What is the most important investigation in septic joints?
Aspirate and send fluid for culture
What are the first line investigations for septic arthritis?
FBC
Elevated CRP and ESR
Blood cultures
Plain x-ray
What is a the most common location of septic arthritis?
Knee
- normally only one joint is affected
What is the scoring criteria used for septic arthritis?
Kocher criteria a score of 2 suggests 40% likelihood and score of 3 suggest 93%
What is the treatment for septic arthritis?
Empirical therapy = flucloxacillin plus rifampicin is first-line
Penicillin allergy = clindamycin
Suspected or confirmed MRSA = vancomycin
Gonococcal arthritis or gram-negative infection = cefotaxime or ceftriaxone
Continue for 3-6 weeks
What is the prognosis for septic arthritis?
Mortality from septic arthritis ranges from 10 to 20% with treatment,
What are the pathways of infection for a prosthetic joint?
Local = been there since surgery, symptoms occur quickly
Haematogenous spread = takes longer to present
What is the gold standard investigation for prosthetic joint diagnosis?
Aspiration
- identifies organisms
- must be done with patient off antibiotics for at least 2 weeks
What are the aims of prosthetic joint infection treatment?
- eradicate sepsis
- relieve pain
- restore function
What is the treatment for prosthetic joint infection?
- Antibiotic suppression = will NOT eliminate sepsis
- Debridement and retention of prosthesis = for acute infections
- Excision arthroplasty = cutting tissue away within the joint to allow it to move again
- One stage exchange arthroplasty = remove + add in new prothesis in same surgery
- Two stage exchange arthroplasty = remove and wait to do reconstruction
- Amputation
What is the most likely causative microorganism for upper limb joint inflammation?
Propionibacteria
- They are colonisers of humans from the above the waist
- Can even be shed by blinking the eyes
- Therefore may represent more of a threat in upper limb prostheses and Spines
What causes joint inflammation?
- Inflammatory arthritis:
Rheumatoid arthritis
Seronegative spondyloarthritis
- Psoriatic
- Ank Spond
- Reactive Arthritis
- Enteropathic – Crohns and Ulcerative Colitis related
Crystal arthrits – gout and pseudogout - septic arthritis
What is the epidemiology of RA?
- F>M
- smokers
- middle aged
- family history
What are the key features of RA?
Symmetrical small joints, hands wrists feet
Big joints involved later, bad prognostic sign if involved at presentation
No spinal involvement
What are the key features of seronegative/inflammatory arthritis?
- Asymmetrical big joints, with spinal involvement
- More common in men
- Associated symptoms = Inflammatory bowel, or GI infection, eye inflammation and psoriasis
- Nail involvement predicts arthritis in patients with psoriasis
What are the key features of psoriatic arthritis?
RA like
Distal interphalangeal involvement (OA more common)
Mutilans - rare
Dactylitis – sausage digit / toe
Asymetrical large joints + spine
CRP may not be significantly raised
What is psoriatic Arthritis?
An inflammatory arthritis associated with psoriasis. Can vary in severity from mild stiffening and soreness in the joint or the joint can be completely destroyed arthritis mutilans
What % of people with psoriasis will develop psoriatic Arthritis?
10-20% and it usually occurs within 10 years of developing the skin change
What is the pathophysiology of psoriatic Arthritis?
It has a strong genetic component and although not fully understood the activation of CD8+ T cells is thought to play a crucial role
What are the signs of psoriatic Arthritis?
Joint tenderness and warmth
Dactylitis: swelling of the whole digit (sausage fingers)
Enthesitis: Inflammation of the tendons
Plaques of psoriasis on the skin
Pitting of the nails
Onycholysis (separation of the nail from the nail bed)
What are some other complications of psoriatic Arthritis?
Eye disease
Aortitis
Amyloidosis
What are the different patterns in which psoriatic Arthritis can present?
not a single pattern of affected joints like osteoarthritis or rheumatoid:
Symmetrical polyarthritis presents similarly to rheumatoid arthritis and is more common in women. The hands, wrists, ankles and DIP joints are affected.
Asymmetrical pauciarthritis affecting mainly the digits (fingers and toes) and feet. Pauciarthritis describes when the arthritis only affects a few joints.
Spondylitic pattern is more common in men.
What is used to screen patients who have psoriasis for arthritis?
PEST screening tool
Patients are asked about: joint pain, swelling, nail pitting
Can also use the CASPAR criteria
What are some x-ray changes seen in psoriatic Arthritis?
- Periostitis- thickened and irregular outline of the bone
- Ankylosis- where bones are joined together
- Pencil-in-cup appearance- the classic x-ray change to the digits is the “pencil-in-cup appearance”.
- central erosions of the bone beside the joints
- appearance of one bone in the joint being hollow and looking like a cup whilst the other is narrow and sits in the cup.
What are the key features of the 2 types of crystal arthritis?
Typically acute intermittent episodes joint inflammation
- Gout (6x more common in men = MC type)
feet, ankles, knees, elbows, hands
Hyperuricaemia
Risks – beer, renal impairment, diuretics, aspirin, FH (affect how kidney deals with uric acid) - Pseudogout – 3 x more common in women
calcium pyrophosphate crystals deposits
wrists, knees, hands
Typically on background of OA
Chondrocalcinosis on xray
What are the key features of ostesoarthritis?
NOT INFLAMMATORY (would be sudden onset)
Usually slow onset – months to years
Typically weight bearing joints DIPs, PIPs, thumb bases, big toes
Minimal early morning stiffness (gelling)
No variability to joint swelling
Normal CRP
Clear changes on xray
What are the differences between inflammatory and osteoarthritis?
Inflammatory
- happen at any age
- rapid onset
- symmetrical
- small joints of hand and feet
- stiffness worse in mornings
- fatigue, fever, night sweats
Osteoarthritis:
- later in life
- slow onset, years
- initially asymmetrical, polyarthritis
- weight bearing joints
- stiffness <1 hour + worse at end of day
What is gout?
A type of crystal arthritis which is associated with chronically high levels of uric acid. Urate crystals are deposited in the joint causing it to become hot swollen and painful
What happens to uric acid levels in Gout in an acute flare up?
Normal
- as the uric acid is in the joints not the blood
- if measured when not having a flareup then the uric acid levels would be high
What is the pathophysiology of Gout?
- Uric acid formed as a breakdown product of purines
- uric acid has a limited solubility in the blood and when there is too much uric acid it can become a urate ion and bind to sodium
- this forms urate crystals which deposit in areas with slow blood flow the joints and kidney tubules
- The immunological reaction initiated to try and remove them, leads to acute pain and swelling
( Only ‘Curable’ form of inflammatory arthritis)
What causes an increase of uric acid intake?
- beer
- diet = red meat, shellfish, offal, purine rich
- sweetened soft drinks (fructose shares renal uric acid transporter)
- conditions leading to increased cell turnover (haematological malignancy + psoriasis)
Why does alcohol increase risk of gout?
Beer / lager / stout equally bad
All rich in guanosine and then converted into uric acid
Small increased risk with spirits
No increased risk with wine
What will affect the output of uric acid?
- Renal impairment (any cause)
- Drugs:
Low dose aspirin reduces renal clearance by 10%
Diuretics – worse with higher dose
Cyclosporin, TB drugs, theophyllines
Genetics – affects renal clearance of uric acid
Fructose – shares renal uric acid transporter
How will Gout first present?
Sudden acute swollen big toe
Risk factors for Gout?
Renal impairment
Beer
Diuretics
Aspirin
Family History
Fructose
What joints are typically affected in acute gout?
1st MTPJ 90%
Midfoot, ankle, knee, wrist, elbow hand
Periarticular involvement - Olecranon bursitis
Systemic features can occur
What are the investigations for Gout?
FBC (expect raised WCC)
U+E
LFT if concern re alcohol
Serum Uric Acid (often normal during acute attack)
CRP
Joint aspiration (to exclude septic arthritis)
Xray if recurrent episodes or concern re sepsis
What are the 4 clinical phases if Gout is untreated?
asymptomatic hyperuricemia,
acute/recurrent gout,
intercritical gout,
chronic tophaceous (uric acid deposits in the skin) gout
What are the x-ray signs of gout?
Joint space maintained
Lytic lesions
Punched out erosions
Sclerotic borders with overhanging edges
What is the treatment for acute Gout?
- NSAID (short course) - unless Renal failure, Peptic Ulcer Disease, Some pts with asthma
- Colchicine - 500ug 2-3 times daily
- Corticosteroids - Intra-articular, Oral - low dose (5-10mg short course)
Other analgesics don’t work!! (as don’t deal with inflammation)
- advice about lifestyle
- ensure patient knows to return if further attacks
What is the indication and treatment for long term Gout?
Indication:
1. Recurrent attacks
2. Evidence of tophi or chronic gouty arthritis
3. Associated renal disease
4. Normal serum Uric acid cannot be achieved by life-style modifications
Medication:
1. Allopurinol – Xanthine Oxidase Inhibitor
2. Febuxostat – more potent Xanthine Oxidase Inhibitor
3. Benzbromarone / Probencid – if allergic / intollerant
What is the aim of gout treatment?
Aim of chronic gout management is to reduce Uric acid below <300 umol/l
- Start at 100mg allopurinol and increase every 2-4 weeks until target met.
- Engage patient in this – more likely to comply and make lifestyle modification
What is used to prevent gout?
Lifestyle management and a Xanthine oxidase inhibitor
First-line Allopurinol
Second-line Febuxostat
What are the complications of Gout?
Disability and misery
Tophi (punched out erosions)
Renal disease:
Calculi 10 -15%
Chronic urate nephropathy
Acute urate nephropathy (cytotoxics)
What is pseudogout?
Is a form of inflammatory arthritis caused by the deposition of calcium pyrophosphate crystals in the synovium
What are risk factors of pseudogout?
Hyperparathyroidism
Hemochromatosis
Hypomagnesaemia
Hypophosphatemia
Wilson’s disease
Acromegaly
Describe the pathophysiology of pseudogout?
Deposition of calcium pyrophosphate triggers synovitis with the knee, shoulder and wrist most commonly being affected
Can be acute or chronic
What will joint aspiration for pseudogout show?
No bacterial growth
Calcium pyrophosphate crystals
Rhomboid shaped needles
Positive birefringent of polarised light
What would an x-ray of pseudogout show?
Chondrocalcinosis is the classic x-ray change in pseudogout. It appears as a thin white line in the middle of the joint space caused by the calcium deposition. This is pathognomonic (diagnostic) of pseudogout.
At what point is an X-ray useful for investigating RA?
only 6 months after onset would you see an abnormal X-ray
What is the prognosis of RA?
if treated within ‘window of opportunity’ can control disease and prevent damage
What is the clinical presentation of RA?
Pain and Swelling of joints = typically small joints hands, wrists, forefeet
Early morning stiffness (often prolonged)
Sudden change in function
Intermittent, Migratory or Additive involvement
What are some signs of rheumatoid arthritis?
- Z shaped deformity to the thumb
- Swan neck deformity
- Boutonnieres deformity- due to a tear in the central slip of the extensor components of the finger. This means when they try to straighten their finger it cause it to bend and flex
- Ulnar deviation of the fingers at the knuckles
What are some extra-articular manifestations of rheumatoid arthritis?
Pulmonary fibrosis
Anaemia
Cardiovascular disease - pericardial effusion
Amyloidosis
Bronchiolitis obliterans (inflammation causing small airway destruction**
Felty’s syndrome (RA, neutropenia and splenomegaly)
Sjogren’s syndrome
Subcutaneous nodules
Peripheral sensory neuropathy
Episcleritis (redness + pain of sclera)
What is found in a physical examination of RA?
- struggle to form a fist
- doesn’t involved DIP joint
- symmetrical
- deformity unusual at presentation
What are the investigations for RA?
CRP (+/- ESR) raised
Rheumatoid Factor
- Falsely positive in 10-15% population
- 70% of patients with RA are positive
Anti-CCP (cyclic citrullinated peptide)
- Almost never falsely positive
- 70% of patients with RA are positive
- Selects the subset of patients with most aggressive disease
Joint X-rays
What is the main aim of treatment of RA?
- to suppress inflammation as completely and quickly as possible once diagnosis confirmed without making our patients ill
- Improve symptoms, prevent/reduce damage, prevent premature mortality
What is the diagnostic criteria for rheumatoid arthritis?
Comes from the American college of rheumatology
1. The joints involved (more and smaller joints score higher)
2. Serology
3. Inflammatory markers
4. Duration of symptoms longer or less than 6 weeks
Score is added up and a score of greater than 6 indicates rheumatoid arthritis
Who is considered to have the worst prognosis with rheumatoid arthritis?
younger onset
Male
Presence of RF and anti-CCG
What is treatment of RA?
- DMARD treatment = methotrexate, sulphasalazine, leflunomide, hydroxychloroquine
- referral to physio, OT
- escalate to biologic treatment if resistant disease e.g. anti-TNF, rituximab, JAK inhibitors
What is the first-lie monotherapy for rheumatoid arthritis?
Any one of methotrexate, leflunomide or sulfasalazine
What second line therapy for rheumatoid arthritis?
Two of methotrexate, leflunomide or sulfasalazine
What is third line treatment for rheumatoid arthritis?
Methotrexate plus a TNF inhibitor e.g., infliximab
What is fourth line treatment for rheumatoid arthritis?
Methotrexate plus rituximab (monoclonal antibody)
What is the mechanism of action for Methotrexate?
(DMARD)
- competitively inhibits dihydrofolate reductase > inhibits folate synthesis
- 100,000 times greater affinity than dihydrofolate
(Must give 5mg of Folic Acid ONCE weekly not on the same day as Methotrexate)
What is used to monitor rheumatoid arthritis?
CRP levels and DAS28
What is the leading cause of death in rheumatoid arthritis?
Accelerated atherosclerosis leading to cardiovascular disease
Describe the pathophysiology of rheumatoid arthritis
- Environmental triggers cause modification of self-antigens e.g., arginine is converted to citrulline in type 2 collagen.
- Due to susceptibility due to genes the immune cells cannot differentiate between self and non-self antigen.
- This causes an inflammatory response and cytokines Interferon gamma, IL-17, TNF, Il-1 and IL6 are secreted
- This creates a pannus (thick synovial membrane). This damages the cartilage, soft tissue and bones. The cytokines can also escape and affect multiple organ systems
What are two autoantibodies that are found in rheumatoid arthritis?
- Rheumatoid factor =
- 70% of patients with rheumatoid arthritis.
- It targets the Fc portion of the IgG antibody.
- This causes activation of the immune system against own IgG antibodies.
- RF is mainly IgM antibodies - Cyclic citrullinated peptide antibodies (anti-CCP antibodies) =
- target citrullinated proteins.
- This forms immune complexes which can accumulate and activate the complement system.
- Often found before development of rheumatoid arthritis
What is the typical presentation of rheumatoid arthritis?
Symmetrical polyarthritis: (on both sides of body)
Pain, swelling and stiffness in the small joints of the hands and feet. The onset can be rapid or over months to years
What type of joint problems are NSAIDs most useful for?
usually helpful for most inflammatory causes of pain