henoch-schonlein purpura

Question 1

define HSP

Answer 1

IgA vasculitis, clinical diagnosis
features include rash and one or more of:
- arthritis/arthralgia
- abdominal pain
- nephritis

Question 2

pathophys of HSP

Answer 2

immune mediated small vessel IgA vasculitis
IgA and compliment C3 are depositied into the vessel walls leading to inflammation
mechanism underlying is unknown, thought to be triggered by abnormal immune response following upper respiratory tract infection

Question 3

epidemiology of HSP

Answer 3

most common cause of non-thrombocytopaenic purpura
incidence peaks 4-6 years old
M>F
URTI may occur 7-14 days before symptoms
seasonal peak in winter

Question 4

Hx of HSP

Answer 4

clinical manifestations vary in order of appearance
pupura occurs in all cases but is the presenting complaint in only 75% of cases
recent URTI is present in 50% of cases, commonly viral or GAS infections
abdominal pain associated with nausea and vomiting

Question 5

general observations

Answer 5

hypertension (suggests renal involvement)
low grade fever may be present

Question 6

skin Ex

Answer 6

palpable purpura, peteciae and eccymosis
may be preceded by urticarial, erythematous, maculopapular os bullous skin lesions, usually cymmetrical on gravity/presssure depednant areas (eg. buttocks and lower limbs)
panful non pitting subcutaneous oedema (commonly periorbital or depednant areas (hands, feet, scrotum)

Question 7

joints Ex

Answer 7

transient arthralgia +- arthritis
usually affects large joints of the lower limbs, rarely upper limbs
usually no effusion or warmth
may cause difficulty weight bearing

Question 8

abdominal Ex

Answer 8

diffuse abdominal pain intermittant and colicky
generalised tenderness
diarrhoea with occult blood
signs of bowel obstruction/pritonism
most common complication is intussusception

Question 9

genital Ex

Answer 9

testcular pain, orchitis, necrosis, cord hematoma
exclude testicualr torsion

Question 10

urinalysis

Answer 10

haematuria (microscopic or macroscopic)
protienuria (mild to severe)

Question 11

investigation

Answer 11

urinalysis is usually the only one needed in classic presentation
urine MC, urinary protein creatinine ratio and UEC and albumin may also be necessary if there is hypertension, macroscopic haematuria or significant proteinuria
FBC to rule out ITP?

Question 12

investigation for severe abdo pain

Answer 12

abdominal US to exclude intussusseption

Question 13

treatment flow

Answer 13

Question 14

follow up

Answer 14

critical to ientfy subsequent renal involvement which rarely requires renal biopsy +- immunosuppression

Question 15

treatment for mild pain

Answer 15

subcutaneous odema is managed with bed rest and elevation of the affected area
paracetamol and NSAIDs

Question 16

treatment for moderate/severe pain

Answer 16

consider steroids (prednisolone) for moderate/severe joint pain or abdominal pain
may reduce duration of symptoms, do not impact rate of long term renal complications

Question 17

prognosis

Answer 17

usually resolves within 4 weeks, rash is usually last symptom to remit
joint pain usually resolves within 72 hours
uncomplicated abdominal pain usually resolves within 24-48 hours
HSP may recur within 4 months of the intiial presentation, subseuent episodes are usually associated with milder symptoms of shorter duration that the previous episodes

Question 18

how do you know if its meningoccocal disease

Answer 18

child will be systemically unwell with a high grade fever
may also be signs of shock (hypotension and tachycardia)
child is usually stable in HSP

Question 19

how do you know if its actually ITP

Answer 19

fall in platelet count

Question 20

how do you know if its actually haemolytic uraemic syndrome

Answer 20

triad of thrombocytopaenia, AKI, and microangiopaathic haemolytic anaemia
caused by E coli infection
also presents with abdo pain and petechial rash, key distinguishing feature is bloody diarrhoea

Question 21

progression to renal failure

Answer 21

1% of HSP
more likley in patients that present withh nephrotic or nephritic syndrome