Rheumatology Flashcards
What is juvenile idiopathic arthritis (JIA)?
Autoimmune inflammation of the joints lasting more than 6 weeks, in a patient under the age of 16.
Presentation of juvenile idiopathic arthritis.
- joint pain
- swelling
- stiffness
What is Still’s disease?
A systemic juvenile idiopathic arthritis causing:
- salmon pink rash
- fevers
- weight loss
- lympadenopathy
- splenomegaly
- muscle pain
Blood test findings in Still’s disease.
a) ANA
b) RF
c) CRP
d) ESR
e) platelets
f) serum ferritin
a) normal
b) normal
c) raised
d) raised
e) raised
f) raised
What is the main complication of Still’s disease.
Macrophage activation syndrome - severe activation of the immune system causing a massive inflammatory response.
It results in acutely unwell child with DIC, anaemia, thrombocytopenia, bleeding and a non-blanching rash.
It is life-threatening - a key feature is low ESR.
Non-infective differentials for a fever lasting >5 days in children.
- Kawasaki disease
- Still’s disease
- rheumatic fever
- leukaemia
What is
a) polyarticular JIA
b) oligoarticular JIA
a) idiopathic inflammatory arthritis of >5 joints
b) idiopathic inflammatory arthritis of ≤4 joints
What is a complication of oligoarticular JIA?
Anterior uveitis - refer to opthalmologist.
What is enthesitis-related arthritis?
Inflammatory arthritis plus enthesitis - inflammation at the point where the tendon of a muscle inserts into a bone.
Genetic association of enthesitis-related arthritis.
HLA-B27 mutation
Examination findings consistent with enthesitis-related arthritis.
Palpate areas to elicit tenderness of entheses:
- interphalangeal joints in the hand
- wrist
- greater trochanter
- ASIS
- patella
- base of achilles
What is juvenile psoriatic arthritis?
Can present as:
- symmetrical polyarthritis affected small joints
- asymmetrical arthritis affect large joints
Associated with psoriasis.
Examination findings consistent with juvenile psoriatic arthritis.
- plaques of psoriasis on the skin
- nail pitting
- onycholysis (separation of nail from nail bed)
- dactylitis (inflammation of full finger)
- enthesitis (inflammation of the entheses)
Management of juvenile idiopathic arthritis.
Refer to a specialist in paediatric rheumatology and manage as part of an MDT:
- NSAIDs (e.g. ibuprofen)
- steroids
- DMARDs
- biologic therapy
What is Henoch-Schonlein purpura (HSP)?
IgA vasculitis that presents with a purpuric rash affecting the lower limbs and buttocks in children.
Inflammation occurs in affected organs due to IgA deposits in blood vessels.
Features of HSP.
- purpura (100%)
- joint pain (75%)
- abdominal pain (50%)
- renal involvement (50%)
Why is there a rash in HSP?
Inflammation and leaking of blood from small blood vessels under the skin results in purpura.
Diagnostic workup for HSP.
- FBC and blood film (?thromboyctopenia, sepsis, leukaemia)
- renal profile (?kidney involvement)
- serum albumin (?nephrotic syndrome)
- CRP (?sepsis)
- blood cultures (?sepsis)
- urine dipstick (?proteinuria)
- blood pressure (?hypertension)
EULAR/PRINTO/PRES criteria for HSP diagnosis.
Palpable purpura PLUS one of:
- diffuse abdominal pain
- arthritis
- IgA deposits on histology
- proteinuria / haematuria
Management of HSP.
Supportive treatment with simple analgesia, rest and proper hydration.
Close monitoring:
- urine dipstick (?renal involvement)
- blood pressure (?HTN)
Prognosis of HSP.
Abdominal pain usually settles within a few days.
Relapses are possible in around 50% of patients.
Full recovery in weeks to months.
What is Kawasaki disease?
A systemic, medium-sized vessel vasculitis that affects young, Asian children typically.
Presentation of Kawasaki disease.
- fever >5 days
- widespread erythematous maculopapular rash
- desquamation on palms and soles
Other features:
- strawberry tongue
- lymphadenopathy
- conjunctivitis
Diagnostic workup of Kawasaki disease.
- FBC (?anaemia, thrombocytosis, leukocystosis)
- LFTs (?hypoalbuminaemia)
- ESR raised
- urinalysis (?raised WCC without infection)
- echocardiogram (?coronary artery pathology)
Kawasaki disease course:
1) acute phase
2) subacute phase
3) convalescent stage
1) weeks 1-2; child is unwell; fever; rash; lymphadenopathy
2) weeks 2-4; acute symptoms settle; desquamation and arthalgia; risk of coronary artery aneurysms.
3) weeks 4-8; remaining symptoms settle; blood tests return to normal; coronary aneurysms regress,
Complications of Kawasaki disease.
- coronary artery aneurysm
Management of Kawasaki disease.
- high dose aspirin to reduce the risk of thrombosis
- IV immunoglobulins to reduce the risk of coronary artery aneurysms
Follow up with echocardiograms to monitor for evidence of coronary artery aneurysms.
TOM TIP: Kawasaki disease is one of the few scenarios where aspirin is used in children. Aspirin is usually avoided due to the risk of Reye’s syndrome. This is a unique fact that examiners like to test.
What is rheumatic fever?
An autoimmune condition triggered by streptococcus bacteria, where antibodies made in response also target tissues within the body.
Why is rheumatic fever rare in the UK?
Streptococcus is usually treated by antibiotics before rheumatic fever has chance to develop.
Pathophysiology of rheumatic fever.
Group A beta-haemolytic streptococci infection has antibodies created to fight the infection. These antibodies target the bacteria, and match antigens on the cells of the person’s body.
This results in a type 2 hypersensitivity reaction, where the immune system begins to attack cells throughout the body.
Presentation of Rheumatic fever.
2-4 weeks following a streptococcal infection (ie. tonsillitis):
- fever
- joint pain
- rash
- shortness of breath
- chorea (unpredictable muscle movements)
- nodules
What tissues can be targeted by antibodies in rheumatic fever?
- joint
- heart
- skin
- nervous system
Rheumatic fever - joint involvement.
A migratory arthritis affecting the large joints, with hot and swollen joints.
It is migratory because different joints become inflamed and improve at different times, giving the appearance that the arthritis is moving from one joint to the next.
Rheumatic fever - heart involvement.
Inflammation of the heart tissues can result in:
- pericarditis
- myocarditis
- endocarditis
This leads to:
- tachycardia / bradycardia
- murmur (mitral valve disease)
- pericardial rub
- heart failure
Rheumatic fever - skin involvement.
- subcutaneous nodules over extensor surfaces
- erythema marginatum around the torso and proximal limbs
Rheumatic fever - nervous system involvement.
Antibodies targeting the nervous system can result in chorea - the irregular, uncontrolled and rapid movement of the limbs.
Diagnostic workup for rheumatic fever.
- throat swab for bacterial culture
- ASO antibody titres
- echocardiogram, ECG and CXR to assess heart involvement
Role of ASO antibody titres in diagnosing rheumatic fever.
ASO antibodies are produced in response to streptococcus infection, indicating recent infection and supporting a diagnosis of rheumatic fever.
Jones criteria for diagnosis of rheumatic fever.
Two major criteria OR one major criteria + two major criteria.
Major Criteria:
J - joint arthritis
O - organ inflammation
N - nodules
E - erythema marginatum rash
S - sydenham chorea
Minor Criteria:
F - fever
E - ECG changes
A - arthralgia
R - raised ESR / CRP
Management of rheumatic fever.
Treat any streptococcus infection with penicillin V.
Management of rheumatic fever:
- NSAIDs
- aspirin and steroids
- prophylactic antibiotics
- monitoring and management of complications
Complications of rheumatic fever.
- recurrence of rheumatic fever
- valvular heart disease (mitral stenosis)
- chronic heart failure
