What is the most probable dx?
a. Measles
b. Bullous-pemphigoid
c. Rubella
d. ITP
e. HSP
answer:E
Henoch–Schönlein purpura
Small vessel
vasculitis associated with IgA immune complexes.
A triad of arthritis, colicky
abdominal pain, and palpable, papular, purpuric rash. Characteristically
affects prepubertal boys.
Clinical features
• Skin rash: palpable purpura over buttocks and lower legs.
Severe skin vasculitis can lead to oedema (dorsum hand, scrotum, and periorbital).
• Arthritis: typically
short-lived affecting large joints (knees, ankles, or elbows).
• Gastrointestinal: colicky abdominal pain (commonest),
malaena, haematemesis, intussusception, perforation, appendicitis.
• Renal: dipstick haematuria and proteinuria
present (50%). Glomerulonephritis and nephrotic syndrome rare.
Investigations
• FBC, renal function, dipstick urinalysis, and full renal investigation with biopsy if evidence of renal
involvement (crescentic IgA glomerulonephritis).
• Skin biopsy rarely necessary: leucocytoclastic
vasculitis.
• Abdominal investigations as per symptoms.
Treatment and prognosis
Most cases have a benign course with complete
resolution of symptoms within 6wks. NSAIDs help arthritis symptoms. Corticosteroids for abdominal pain and arthritis may hasten symptom resolution. Test for haematuria because
nephritis and nephritic syndrome carry worse prognosis for hypertension and
decreased renal function.
N.b
Acute immune
thrombocytopenia
ITP is caused by IgG autoimmune antibody to platelet cell
membrane antigens leading to platelet destruction in the spleen and liver.
Presentation
• Most present between ages of 2 and 5yrs, but can occur
at any age.
• 60% have preceding viral infection, e.g. upper
respiratory tract infection
(URTI).
• Bruising, purpura, petechiae, mucosal bleeding, menorrhagia.
• Intracranial bleeds very rare (< 0.5%); often
associated with trauma.
• Physical examination otherwise usually normal, e.g. no splenomegaly.
Investigation
• FBC: platelet count low, commonly platelet
size increased due to compensatory megakaryocytosis. Otherwise FBC is usually
normal.
• Testing for platelet antibodies is not
clinically useful.
• Bone marrow in ITP normal,
but striking increase in megakaryocytes.
Generally, bone marrow aspirate not indicated if the
child is otherwise well, unless concurrent pancytopenia, hepatosplenomegaly,
lymphadenopathy, or abnormally-increased blasts on FBC suggesting alternative
diagnosis, e.g. aplastic anaemia, acute leukaemia, SLE (adolescent girls) or
bone marrow failure syndrome.
Management
• Do not treat the platelet count, treat the patient! The
aim of treatment is to stop the bleeding not ‘cure’ the disorder, which resolves in its own time. Increases in platelet count will usually
be transient, but are usually sufficient to control current bleeding.
• Moderate bleeding can be controlled with tranexamic acid
20–25mg/kg tds for <5 days, provided haematuria is not present.
• Active treatment is required if patient experiencing significant bleeding, mucosal
haemorrhage, or haematuria, as all are associated
with increased risk of internal bleeding.
• First line therapy: 4mg/kg prednisolone
for 4 days and then stop.
• Second line therapy: IV IgG 1g/kg over 2 days if steroids not effective,
alternatively can
use anti-D.
• If bleeding life-threatening or intracranial, give 15–20mL/kg of platelets, start prednisolone
and IV IgG
and consider emergency splenectomy.
• Splenectomy for chronic ITP is indicated if disease is not steroid responsive
and child over 5yrs.
• For chronic severe ITP, rituximab has been used
successfully in young children.
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