Rheumatology: Juvenile Idiopathic Arthritis, Ehlers-Danlos & Henoch-Schonlein Purpura

Question 1

What is juvenile idiopathic arthritis (JIA)?

Answer 1

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.

Question 2

When can JIA be diagnosed?

Answer 2

Where there is arthritis without any other cause, lasting more than 6 weeks in a patient under the age of 16.

Question 3

How long does arthritis have to last for a diagnosis of JIA?

Answer 3

> 6 weeks

Question 4

What are the 3 key features of JIA?

Answer 4

• joint pain
• swelling
• stiffness

Question 5

What are the 5 key subtypes of JIA?

Answer 5

1) Systemic JIA
2) Polyarticular JIA
3) Oligoarticular JIA
4) Enthesitis related arthritis
5) Juvenile psoriatic arthritis

Question 6

What is the most common subtype of JIA?

Answer 6

Oligoarticular JIA

Question 7

Common signs & symptoms of JIA?

Answer 7

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

Question 8

What joints does oligoarticular JIA typically affect?

Answer 8

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.

Question 9

Who does oligoarticular JIA typically occur in?

Answer 9

It occurs more frequently in girls under the age of 6 years.

Question 10

What is oligoarticular JIA also known as?

Answer 10

pauciarticular JIA

Question 11

What is a classic associated feature with oligoarticular JIA?

Answer 11

Anterior uveitis - refer to opthalmology

Question 12

Features of oligoarticular JIA?

Answer 12

• large joints affected
• anterior uveitis: eye redness, pain, and vision loss

Typically does not have systemic symptoms.

Question 13

What investigations may be done in JIA?

Answer 13

1) ANA: may be positive, especially in oligoarticular JIA

2) Rheumatoid factor: usually negative

Question 14

Management of JIA?

Answer 14

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

Question 15

What is Ehlers-Danlos syndrome (EDS)?

Answer 15

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.

Question 16

What is defected in Ehlers-Danlos?

Answer 16

Collagen

Question 17

What is a critical differential for Ehlers-Danlos?

Answer 17

Marfan syndrome

Question 18

What are the key features of Ehlers-Danlos?

Answer 18

• Joint hypermobility & joint pain
• Soft and stretchy skin
• Poor wound healing
• Stretch marks (striae)
• Easy bruising
• Bruising
• Chronic pain (can be widespread) & fatigue

Question 19

What score is used to assess for hypermobility and support the diagnosis of Ehlers-Danlos?

Answer 19

The Beighton score

Question 20

Describe the Beighton score

Answer 20

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

Question 21

What cardiac abnormalities are patients with Ehlers-Danlos prone to?

Answer 21

Mitral regurgitation & aortic root dilatation

Question 22

What is Henoch-Schonlein purpura (HSP)?

Answer 22

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.

Question 23

Typical presenting feature of HSP?

Answer 23

Purpuric rash affecting the lower limbs and buttocks in children.

Question 24

What is HSP typically triggered by (2 things)?

Answer 24

An upper airway infection (mainly caused by Streptococcus) or gastroenteritis

Question 25

Who is HSP most common in?

Answer 25

Children <10 y/o

Question 26

What are the 4 classic features of HSP?

Answer 26

1) Purpura (rash) (100%)

2) Joint pain i.e. arthritis/arthralgia (75%)

3) Abdo pain (50%)

4) Renal involvement i.e. glomerulonephritis(50%)

Question 27

What causes the rash in HSP?

Answer 27

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.

Question 28

What are purpura?

Answer 28

Purpura are red-purple lumps under the skin containing blood.

Question 29

Prognosis of HSP in children vs adults?

Answer 29

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.

Question 30

Describe rash seen in HSP?

Answer 30

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.

Question 31

What joints are most affected by arthralgias/arthritis in HSP?

Answer 31

Knees & ankles

Question 32

Describe GI features typically seen in HSP?

Answer 32

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.

Question 33

What is the most common GI complication in HSP?

Answer 33

Intussusception

Question 34

If severe, what 3 GI complications can HSP cause?

Answer 34

1) GI haemorrhage

2) Intussusception

3) Bowel infarction

Question 35

What renal features may be seen in HSP?

Answer 35

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

Question 36

How do you know if HSP has caused nephrotic syndrome?

Answer 36

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.

Question 37

What is the most important aspect of investigating HSP?

Answer 37

Excluding other serious pathology, such as meningococcal septicaemia and leukaemia.

Question 38

What are 4 key differentials for HSP?

Answer 38

1) meningococcal septicaemia
2) leukaemia
3) idiopathic thrombocytopenic purpura
4) haemolytic uraemic syndrome (HUS)

Question 39

How is HSP typically diagnosed?

Answer 39

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.

Question 40

Give some investigations that may be done in HSP to exclude other differentials?

Answer 40

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

Question 41

Management of HSP?

Answer 41

Most recover spontaneously, require supportive management.

1) Simple analgesia e.g. paracetamol
2) Steroids: for those with nephrotic-range proteinuria

Question 42

How should patients with HSP be monitored?

Answer 42

Patients should be followed for at least 6 months with periodic urinalysis and BP monitoring (for HTN).

Question 43

Prognosis of HSP?

Answer 43

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.