Rheumatoid Diagnostics

Question 1

Basic blood tests

Answer 1

FBC
Urea and electrolytes (U&E)
Liver function tests (LFT)
Bone profile
Erythrocyte sedimentation rate (ESR)
C-reactive protein (CRP)

Question 2

Liver function tests content

Answer 2

Bilirubin
Alanine aminotransferase (ALT)
Alkaline phosphatase (ALP)
Albumin

Question 3

Bone profile content

Answer 3

Calcium
Phosphate (PO4)
Alkaline phosphatase (ALP)

Question 4

CRP

Answer 4

More specific for inflammation

SLE:
-normal
Exception - if significant synovitis or inflammatory pleural or pericardial effusion

Question 5

Autoantibodies in RA

Answer 5

Rheumatoid factor

Cyclic citrullinated peptides (CCP) antibodies
-more specific than RF
-associated with worse prognosis

Question 6

Synovial fluid analysis

Answer 6

Suspected septic arthritis
Diagnosing crystal arthritis

Gout - needle shaped and negative
Pseudogout - rhomboid shaped and positive

Question 7

Septic v Reactive

Answer 7

Synovial fluid culture - positive / sterile
Antibiotic therapy - yes / no
Joint lavage - yes / no

Question 8

Imaging

Answer 8

X ray
- first line, cheap, widely available

CT scan
-more detailed

MRI
-best for tendons and ligaments
-best for spinal imaging
-expensive and time consuming

Ultrasound
-tendons and ligaments
-good for smaller joints, not for larger

Question 9

Osteoarthritis X ray features

Answer 9

Joint space narrowing
Subchondral bony sclerosis
Osteophytes
Subchondral cyst

Question 10

SLE

Answer 10

Autoimmune connective tissue disease

Arthritis
Skin rash
Mouth ulcer
Kidney disease
Pleural effusion
Pericardial effusion

Question 11

Sjögren’s syndrome

Answer 11

Autoimmune connective tissue disease

Dry eyes
Dry mouth
Extra-articular feature

Question 12

Polymyositis

Answer 12

Autoimmune connective tissue disease

Muscle inflammation
Weakness
High CK

Question 13

FBC

Answer 13

Haemoglobin
-inflammatory arthritis: decrease or normal
-osteoarthritis: normal
-septic arthritis: normal

MCV
-normal
-normal
-normal

WCC
-normal
-normal
-increase (leukocytosis)

Platelet count
-normal or increase
-normal
-normal or increase

Question 14

U&E content

Answer 14

Urea
Creatinine
Sodium
Potassium

Question 15

U&E

Answer 15

High creatinine is worse renal clearance

Rheum disease can affect kidneys
-SLE - lupus nephritis
-vasculitus - nephritis
-NSAIDs can cause kidney impairment

Question 16

Liver function test

Answer 16

DMARDs can cause liver damage
Patients in methotrexate need regular blood tests

Low albumin - either problem of synthesis or problem of leak from kidney

Question 17

Bone profile

Answer 17

Paget’s disease of bone: increased ALP
Osteomalacia: ALP normal or increased, Ca and PO4 normal or decreased
Osteoporosis: all normal

Question 18

ESR

Answer 18

Elevated due to
-elevated immunoglobulin level
-paraprotein (myeloma)
-anemia
-tends to rise with age

SLE:
-high

Question 19

Anti nuclear antibodies (ANA)

Answer 19

High titre ANA in combination with correct clinical features may indicate one of the autoimmune connective tissue diseases

Only order if suspected autoimmune connective tissue disease

Neg rules out SLE
Pos not necessarily SLE

Question 20

If ANA is positive

Answer 20

Extractable nuclear antigens (ENA)
Ro- lupus or sjogrens
La - lupus or sjogrens
RNP - lupus or mixed connective tissue disease
Smith - lupus
Jo-1 - polymyositis

Question 21

Rheumatoid arthritis X ray

Answer 21

Soft tissue swelling
Peri-articular osteopenia
Bony erosions

Question 22

Rheumatoid arthritis ultrasound

Answer 22

Synovial hypertrophy
Increased blood flow
May detect erosion not seen on X ray

Better for synovitis

Question 23

Scleroderma

Answer 23

Autoimmune connective tissue disease

Vasculopathy
Skin thickening
Organ fibrosis