RA Flashcards
Define RA [1]
Rheumatoid arthritis is an autoimmune condition that causes chronic inflammation in the synovial lining of the joints, tendon sheaths and bursa. It is a type of inflammatory arthritis which occurs in a symmetrical pattern
State why synovial joints are susceptible to inflammatory injury [2]
Presence of rich network of fenestrated capillaries
* Fenestrated capillaries: become more leaky so plasma and immune cells can enter synovial membrane and joint cavity
Limited ways it can respond
Which cell types are the first to respond in RA? [1]
Neutrophils
Describe the basic pathophysiology of RA
current theory for the pathophysiology of RA is that exposure to an external trigger in a genetically predisposed individual leads to an abnormal, autoimmune response, which targets synovial joints resulting in chronic inflammation and joint damage
Following a suspected triggering event, there is development of self-citrullination: alteration of a positively charged arginine amino acid into the neutral citrulline
- The immune system then reacts to these citrullinated proteins, which is characterised by development of anti-cyclic citrullinated peptide (anti-CCP) antibodies.
Also get infiltration of synovial joints with immune cells and a subsequent pro-inflammatory response causing the classic synovitis
At joint level: synovial membrane hyperplasia, or ‘thickening’, which subsequently damages cartilage - called a pannus. There is subsequent boney loss, which manifests as localised and periarticular boney erosions.
What is a pannus? [1]
Where are pannus created? [1]
What can be the effect of pannus creation ? [2]
Villi like projections caused by proliferation of SF and subintima:
Created at the small microenvironment of bone-cartilage junction
. Concentration of pro-inflammatory cytokines causes increase in osteoclasts and thickening of lining and subintima
Causes synovial membrane to grow over and erode articular cartilage
2nd year content
The most common gene associated with rheumatoid arthritis is []
The most common gene associated with rheumatoid arthritis is HLA DR4.
Which antibodies are present in RA? [2]
RF; most often IgM ; found in70% ptx targets Fc portion of IgG
Anti-cyclic citrullinated peptide antibodies (anti-CCP antibodies)
Describe the clinical features of RA
Polyarthropathy:
- multiple joints affected, usually in symmetrical distribution; typically the small joints of hands or feet (MCP most common; PIP; MTP)
- On palpation of the joints, there will be tenderness and synovial thickening, giving them a “boggy” feeling.
- Morning stiffness lasting more than 30 mins
- Joint swelling
- Cervical (but not lumbar) spine can be affected
- Knees, ankle, hips and shoulders
- Pain on palpitation
Muscle atrophy:
- may see ‘guttering’ between extensor tendons in hands due to wasting of the interossei muscles
Systemic symptoms
- myalgia
- fatigue
- low-grade fever
- weight loss
- low mood
TOM TIP: Rheumatoid arthritis very rarely affects the distal interphalangeal joints. Enlarged and painful distal interphalangeal joints are more likely to represent Heberden’s nodes due to osteoarthritis.
Describe what is meant by a boutonniere and swan-neck deformity [2]
Boutonniere deformity:
- flexion at the PIP joint with hyperextension of the distal interphalangeal (DIP) joint
- caused by a tear in the central slip of the extensor components at the proximal interphalangeal (PIP) joint.
Swan-neck deformity:
- hyperextension at the PIP joint with flexion of the DIP joint
Name two other hand signs of RA (asides from swan-neck and Boutonniere deformities) [2]
Name a foot sign [1]
Ulnar deviation at MCPs:
- subluxation of the MCP joints with deviation of the fingers towards the ulnar bone due to dislocation of flexor tendons and disruption of extensor tendons.
Z-deformity at wrist:
- hyperextension of interphalangeal joint of thumb in association with carpal bone rotation and radial deviation as well as ulnar deviation at MCPs
- deformity to the thumb
Hammer toes:
- compensatory flexion of the toes due to weakening and subluxation of surrounding tendons.
Describe why RA can lead to spinal cord compression [1]
Atlantoaxial subluxation occurs in the cervical spine.:
- Synovitis and damage to the ligaments around the odontoid peg of the axis (C2) allow it to shift within the atlas (C1).
Describe the extra articular manifestations of RA:
- occular [4]
- oral [2]
Ocular
* Keratoconjunctivitis sicca: refers to dry eyes. Seen in 10%. If accompanied with xerostomia (dry mouth) suggestive of secondary Sjögren’s syndrome.
* Episcleritis: inflammation of superficial layer of sclera
* Scleritis: more aggressive inflammation of the whole sclera
* Scleromalacia perforans
Oral
* Xerostoma (dry mouth): If accompanied with keratoconjunctivitis sicca (dry eyes) suggestive of secondary Sjögren’s syndrome.
* Oral ulcers
Describe the extra articular manifestations of RA:
- pulmonary [3]
- cardiac [4]
Pulmonary
* Interstitial lung disease
* Serositis: inflammation of serous membranes (i.e. pleural, pericardium, peritoneum)
* Costochrondritis
Cardiac
* Pericarditis: as part of serositis
* Myocarditis
* Non-infective endocarditis
* Increased risk of ischaemic heart disease
Describe the extra articular manifestations of RA:
- Renal [1]
- Neurological [3]
- Haemotological [3]
Renal
* Glomerulonephritis (uncommon in the absence of vasculitis)
Neurological
* Peripheral neuropathy: diffuse sensorimotor neuropathy or mononeuritis multiplex
* Entrapment mononeuropathies: carpal tunnel syndrome
* Cervical myelopathy: typically due to cervical spin involvement or atlantoaxial subluxation
Haematological
* Neutropenia: if combined with splenomegaly known as Felty’s syndrome
* Thrombocytopaenia or thrombocytosis
* Haematological malignancies
Describe 3 dermatological mainfestations of RA [3]
Rheumatoid nodules:
- most present skin complaint (20%). Found on extensor surfaces of upper limb at pressure points (e.g. elbow) as hard nodule. Composed of central fibrinoid necrosis with surrounding fibroblasts. Usually in seropositive patients.
Vasculitis skin rash:
- ulcers, digital gangrene, periungual infarcts, splinter haemorrhages
Pyoderma gangrenosum
Describe the diagnosis of RA
The American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) classification criteria from 2010 can be used to make the diagnosis.
- score of 6/10 is needed
Made up of the categories of:
1. Joint involvment (no. of joints)
2. Serology (antibodies present)
3. Acute phase reactants
4. Duration of symptoms
Rheumatoid arthritis seen in adults of all ages
Rheumatoid arthritis commonly affects the MCP, PIP joints
scleritis (erythema and pain)
episcleritis (erythema)
HLA DR4
Bilateral inflammed 2nd + 3rd MCPs - rheumatoid arthritis
DAS28
Which of the following depicts RA
A
B
C
D
B
