Rheumatology Diagnostics Flashcards
What basic tests are performed in patients in rheumatology?
FBC U&E Liver function tests Bone profile Erythrocyte sedimentation rate (ESR) C-reactive protein (CRP)
In inflammatory arthritis, what type of anaemia is present?
Normocytic anaemia
What is the mean cell volume in patients with inflammatory arthritis?
Normal
What is the WCC in patients with inflammatory arthritis?
Normal
What is the platelet count in patients with inflammatory arthritis?
Normal or increased
In osteoarthritis, what blood abnormalities exist?
Nil
In septic arthritis, what can be said regarding WCC?
Increased due to leukocytosis
In septic arthritis, what can be said regarding platelet count?
Normal or increased
A high creatinine count in patients with rheumatoid disorder can suggest what?
Impaired renal clearance, and suggestive of renal failure.
Which rheumatological disorder is strongly concerned with renal failure?
SLE can manifest as lupus nephritis
How does vasculitis affect the kidneys?
Can cause nephritis
What type of protein is elevated and deposited within the kidney due to chronic inflammation?
Serum amyloid (A) SAA protein
This causes AA amyloidosis
Which four main parameters are examined under a liver function test?
Bilirubin
Alkaline aminotransferase
Alkaline phosphatase
Albumin
What effect doe DMARDs have on the kidneys, and provide an example?
DMARDs can cause liver damage
Methotrexate
How often are LFTs conducted in patients on methotrexate?
LFTs and blood tests are conducted every 8 weeks.
What type of plasma protein is albumin (concerning inflammation)?
Negative acute phase protein
What three main parameters are examined in a bone profile?
Calcium
Phosphate
Alkaline phosphatase (ALP) - produced by bone or liver
Which enzyme is elevated in Paget’s disease?
Alkaline phosphatase (ALP), since there is an abnormally high bone turnover
Which is ALP elevated in Paget’s disease?
Due to an abnormally high bone turnover
What are the clinical features associated with Paget’s disease?
Bone pain
Excessive pain growth
Fracture through area of pathological bone
What can cause an elevated ESR (4)?
Elevated immunoglobulin level
Paraprotein (myeloma)
Anemia
Tends to rise with age
Which marker is specific for inflammation?
C-reative protein
In SLE, what happens to CRP?
CRP is normal
Which factor is elevated in SLE?
ESR
Under what circumstance is ESR and CRP elevated in patients with SLE?
Synovitis (Infection)
Inflammatory pleural or pericardial effusion
Which type of autoantibodies are typical for patients with SLE?
Anti-nuclear antibodies (ANA)
What happens to ANA concentrations after an infection?
Increases transiently following infection
What are the common autoimmune tissue diseases?
SLE
Sjogren’s syndrome
Scleroderma
What ANA dilution suggests a weak concentration?
1:320
What ANA dilution ratio suggests a strong concentration of ANA?
1:1280
A negative test of ANA rules out which disorder?
SLE
Does a positive ANA test confirm a diagnosis of SLE?
NO, other clinical and lab features support diagnosis
What are the five common antinuclear autoantibodies?
Ro La RNP Smith Jo-I
An RNP positive autoantibodies suggests what?
Lupus or mixed connective tissue disease
Which ANA antibodies are associated with Sjogrens?
Ro and La
Which antibodies other than ANA are highly specific for lupus and are useful for monitoring SLE activity?
Double stranded DNA (dsDNA) antibodies
What happens to complement levels in a patient with lupus?
C3 and C4 may decrease in active lupus
What is the diagnostic purpose of a synovial fluid analysis?
To obtain synovial fluid for analysis
What is the therapeutic objective of a synovial fluid analysis?
To relieve symptoms (+/- concurrent steroid injections).
What diagnostic investigation is conducted in a patient with septic arthritis?
Joint aspiration (Gold standard)
What happens after a joint aspiration is conducted?
Sent for microscopy and sensitivity
Enables the causative organism to be identified
Sensitivities from culture guide antibiotic choice
How is gout diagnosed in terms of crystal analysis?
Needle shaped crystals with negative birefringence
What composes gout crystals?
Monosodium urate
How is pseudogout diagnosed in terms of crystal analysis?
Rhomboid shaped crystals with positive birefringence
A synovial fluid culture in reactive arthritis reveals what result?
Sterile
What is the ultimate treatment goal for septic arthritis once a joint aspiration is conducted, and is positive?
Joint lavage for large joints
What is the first-line of imaging in rheumatoid disorders?
X-rays
What is the purpose of CT scan imaging?
To identify detailed bony imaging
What doe MRIs provide?
Provides maximal visualisation of soft tissue structures including tendons and ligaments
Which type of imaging is optical for spinal disorders?
MRI
What is the disadvantage to using MRIs?
Expensive and time consuming
What types of structures are visualised using ultrasound?
Soft tissue structures, good for smaller joint structures
What is the most useful imaging test used in osteoarthritis?
Radiographic (X-ray)
What are four main radiographic features associated with osteoarthritis?
Joint space narrowing
Subchondral bony sclerosis
Osteophytes
Subchondral cysts
What radiographic features are evident in patients with rheumatoid arthritis?
Soft tissue swelling Peri-auricular osteopenia Bony erosions Joint space narrowing Ulnar deviation
Ulnar deviation is associated with which type of arthritis?
Rheumatoid arthritis
What is the treatment aim of rheumatoid arthritis in view of erosions?
Treat early before erosions occur
What is an appropriate investigation to detect for synovitis?
Ultrasound
What utlrasound changes are visible in RA?
Synovial hypertrophy (thickening)
Increased blood flow (as seen as Doppler signal)
May detect erosions not seen on plain X-ray
Why does joint space narrowing occur in rheumatoid arthritis?
Indicates articular cartilage loss (Secondary damage due to synovitis)
Where are osteophytes prevalent in osteoarthritis?
Distal inter-phalangeal joints
What are Heberden’s nodes?
Osteophytes and IPJS
What are Bouchard’s nodes?
Osteophytes at PIPs
Juxta-articular osteopenia is an early radiographic sign of what type of arthritis?
Inflammatory arthritis of any cause
What is the ‘bare area’ in arthritis?
Erosions occur initially at the margins of the join where the synovium is in direct contact with the bone.
