Rheumatology: Juvenile Idiopathic Arthritis, Ehlers-Danlos & Henoch-Schonlein Purpura Flashcards
What is juvenile idiopathic arthritis (JIA)?
A chronic AUTOIMMUNE disease that affects children.
Characterised by joint INFLAMMATION, pain, and stiffness that can lead to joint damage and disability if left untreated.
When can JIA be diagnosed?
Where there is arthritis without any other cause, lasting more than 6 weeks in a patient under the age of 16.
How long does arthritis have to last for a diagnosis of JIA?
> 6 weeks
What are the 3 key features of JIA?
- joint pain
- swelling
- stiffness
What are the 5 key subtypes of JIA?
1) Systemic JIA
2) Polyarticular JIA
3) Oligoarticular JIA
4) Enthesitis related arthritis
5) Juvenile psoriatic arthritis
What is the most common subtype of JIA?
Oligoarticular JIA
Common signs & symptoms of JIA?
Arthritis:
- joint pain & stiffness
- joints that are swollen or warm to touch
Systemic:
- fatigue
- uveitis: blurry vision or painful, red eyes
- rash (salmon pink)
- high, spiking fever
- lymphadenopathy
- anorexia/weight loss
What joints does oligoarticular JIA typically affect?
This subtype of JIA affects 4 joints or less (think oligo-).
Usually it only affects a single joint, which is described as a monoarthritis.
It tends to affect the larger joints, often the knee or ankle.
Who does oligoarticular JIA typically occur in?
It occurs more frequently in girls under the age of 6 years.
What is oligoarticular JIA also known as?
pauciarticular JIA
What is a classic associated feature with oligoarticular JIA?
Anterior uveitis - refer to opthalmology
Features of oligoarticular JIA?
- large joints affected
- anterior uveitis: eye redness, pain, and vision loss
Typically does not have systemic symptoms.
What investigations may be done in JIA?
1) ANA: may be positive, especially in oligoarticular JIA
2) Rheumatoid factor: usually negative
Management of JIA?
The aim of treatment is to reduce inflammation within the joints, minimise symptoms and maximise function.
Mx can involve:
1) NSAIDs e.g. ibuprofen
2) Steroids: either oral, intramuscular or intra-artricular in oligoarthritis
3) DMARDs e.g. methotrexate, sulfasalazine and leflunomide
4) Biologic therapy e.g. TNF inhibitors etanercept, infliximab and adalimumab
What is Ehlers-Danlos syndrome (EDS)?
A group of genetic conditions involving defects in COLLAGEN, causing hypermobility in the joints and abnormalities in the connective tissue of the skin, bones, blood vessels and organs.
What is defected in Ehlers-Danlos?
Collagen
What is a critical differential for Ehlers-Danlos?
Marfan syndrome
What are the key features of Ehlers-Danlos?
- Joint hypermobility & joint pain
- Soft and stretchy skin
- Poor wound healing
- Stretch marks (striae)
- Easy bruising
- Bruising
- Chronic pain (can be widespread) & fatigue
What score is used to assess for hypermobility and support the diagnosis of Ehlers-Danlos?
The Beighton score
Describe the Beighton score
One point is scored for each side of the body, with a maximum score of 9, if the patient can:
1) Place their palms flat on the floor with their straight legs (scores only 1)
2) Hyperextend their elbows
3) Hyperextend their knees
4) Bend their thumb to touch their forearm
5) Hyperextend their little finger past 90 degrees
What cardiac abnormalities are patients with Ehlers-Danlos prone to?
Mitral regurgitation & aortic root dilatation
What is Henoch-Schonlein purpura (HSP)?
A type of IgA vasculitis - this is the most common form of systemic vasculitis in children.
Inflammation occurs in the affected organs due to IgA deposits in the blood vessels.
It affects the skin, kidneys and GI tract.
Typical presenting feature of HSP?
Purpuric rash affecting the lower limbs and buttocks in children.
What is HSP typically triggered by (2 things)?
An upper airway infection (mainly caused by Streptococcus) or gastroenteritis
Who is HSP most common in?
Children <10 y/o
What are the 4 classic features of HSP?
1) Purpura (rash) (100%)
2) Joint pain i.e. arthritis/arthralgia (75%)
3) Abdo pain (50%)
4) Renal involvement i.e. glomerulonephritis(50%)
What causes the rash in HSP?
The rash is caused by inflammation and leaking of blood from small blood vessels under the skin, forming purpura.
Purpura are red-purple lumps under the skin containing blood.
What are purpura?
Purpura are red-purple lumps under the skin containing blood.
Prognosis of HSP in children vs adults?
It is typically self-limiting in the majority of cases occurring in childhood.
It occasionally affects adolescents and adults and often results in more severe disease resulting in renal damage.
Describe rash seen in HSP?
Typically symmetrically distributed, non-blanching palpable purpura, especially on the lower legs, buttocks, knees and elbows.
Purpura are red-purple in colour and are palpable under the skin.
In severe cases, skin ulceration and necrosis can develop.
What joints are most affected by arthralgias/arthritis in HSP?
Knees & ankles
Describe GI features typically seen in HSP?
Colicky abdominal pain which may be severe enough to mimic an acute abdomen.
Bloody stools or melena.
N&V also occurs in about half of patients.
What is the most common GI complication in HSP?
Intussusception
If severe, what 3 GI complications can HSP cause?
1) GI haemorrhage
2) Intussusception
3) Bowel infarction
What renal features may be seen in HSP?
HSP affects the kidneys in around 50% of patients, causing an IgA nephritis.
Feautres:
- micro or macroscopic haematuria
- proteinuria
- can progress to nephrotic syndrome and renal failure
How do you know if HSP has caused nephrotic syndrome?
If there is more than 2+ of protein on the urine dipstick the child has developed nephrotic syndrome and will have a degree of oedema.
What is the most important aspect of investigating HSP?
Excluding other serious pathology, such as meningococcal septicaemia and leukaemia.
What are 4 key differentials for HSP?
1) meningococcal septicaemia
2) leukaemia
3) idiopathic thrombocytopenic purpura
4) haemolytic uraemic syndrome (HUS)
How is HSP typically diagnosed?
The diagnosis of HSP is straightforward when patients present with the classic signs and symptoms of rash, polyarthralgia, abdominal pain, and renal disease.
There are no laboratory tests that are diagnostic for HSP.
However, these tests may be useful for excluding differential diagnoses of symptoms.
Give some investigations that may be done in HSP to exclude other differentials?
1) FBC, coagulation & blood film: for thrombocytopenia, sepsis and leukaemia
2) U&Es: for kidney involvement
3) Urine dipstick: for nephrotic syndrome
4) Serum albumin: for nephrotic syndrome
5) CRP: for sepsis
6) Blood cultures: for sepsis
7) Urine protein:creatinine ratio: to quantify the proteinuria
8) BP: for HTN
Management of HSP?
Most recover spontaneously, require supportive management.
1) Simple analgesia e.g. paracetamol
2) Steroids: for those with nephrotic-range proteinuria
How should patients with HSP be monitored?
Patients should be followed for at least 6 months with periodic urinalysis and BP monitoring (for HTN).
Prognosis of HSP?
Abdominal pain usually settles within a few days.
Patients without kidney involvement can expect to fully recover within 4 to 6 weeks.
A third of patients have a recurrence of the disease within 6 months.
A very small proportion of patients will develop end stage renal failure.
