Rheumatology IV Flashcards
Which organ does microscopic polyangiitis (MPA) most commonly affect - how does this impact presentation of this disease? [2]
Microscopic polyangiitis (MPA)
* It is also an ANCA-associated vasculitis with specificity for pANCA, specifically myeloperoxidase (MPO).
* The main organ affected is the kidney and it can lead to glomerulonephritis with crescentic necrosis causing haematuria.
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.
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
Boutonniere - same positions are buttoning up a shirt
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 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
Which factors indicate a worse prognosis in RA?
Poor prognostic features
* rheumatoid factor positive
* poor functional status at presentation
* HLA DR4
* X-ray: early erosions (e.g. after < 2 years)
* extra articular features e.g. nodules
* insidious onset
* anti-CCP antibodies
Rheumatoid arthritis seen in adults of all ages
Which is the most common occular complication of RA? [1]
keratoconjunctivitis sicca
What are iatrogenic occular complications seen in RA? [2]
- steroid-induced cataracts
- chloroquine retinopathy
What is the difference between epi- and slceritis? [2]
episcleritis (erythema)
scleritis (erythema and pain)
Lung fibrosis caused by rheumatoid arthritis typically affects the:
* Upper zone
* Lower zone
lower zones
DAS28 is used to monitor RA; treat to target is the aim.
What DAS28 scores would indicate:
- disease remission [1]
- low severity [1]
- medium severity [1]
- high severity [1]
- disease remission: < 2.6
- low severity: 2.6 - 3.2
- medium severity 3.2 - 5.1
- high severity: > 5.1
Name this deformity seen in the hand associated with RA [1]
Describe the changes in hand position that occurs [2]
Describe the initial treatment plan for RA with MILD disease activity at initial presentation: not pregnant or planning pregnancy
1st Line: conventional DMARD:
- hydroxychloroquine - it is better tolerated and has a more favourable risk profile than other DMARDs
Consider: Corticosteroid
- Prednisolone
Consider: non-steroidal anti-inflammatory drug (NSAID)
- ibuprofen
NB: hydroxychloroquine: should only be considered for initial therapy if mild
BMJBP
State 5 side effects of corticosteroids
Osteoporosis; weight gain; DM; HTN
How do you manage / monitor ongoing methotrexate; SSZ and LEF prescription? [3]
FBC and LFTs are to be monitored every 2 weeks for the
first 6 weeks (induction phase) and with any increased
dose, and then monthly for 3 months.
Describe the MoA [1] and AEs [3] of MMF
MoA:
- Inhibits enzyme used for de novo purine synthesis - effects T & B cells
AEs:
- GI upset
- Infections
- Bone marrow suppression
What do you screen for prior to starting methotrexate; SSZ and LEF tx? [3]
- FBC; UEs; LFTs
- Viral serology screen
- Baseline CXR - for MTX as can cause PF
- Baseline BP for LEF
What should you offer women prior to cyclophosphamide treatment? [1]
Egg harvesting treatment as causes infertility
Describe the MoA and side effects of cyclophosphamide
MoA:
- Alkylating agent - cross links DNA strands, leading to cell death
Effects:
- Bone marrow suppression
- Bladder inflammation - hamorrhagic cystitis
- Infertility
- N&V
