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Chapter 12: Bleeding disorders 495

Management ceptors within the spleen) shorten the course of the con-
Vitamin K (phytomenadione) can be given as iv. or im dition. Prior to using steroids a bone marrow aspirate
injections. If given orally in malabsorption syndromes it must be performed to exclude leukaemia. Platelet trans-
must be in a water-soluble form. fusions are not used unless life threatening bleeds occur.
In refractory cases splenectomy can be considered. Pre-
vious response to intravenous immunoglobulin is sug-
Acute immune thrombocytopenia
purpura gestive of a favourable outcome of splenectomy.

Definition Prognosis
Purpura arising secondary to a fall in platelet count In children 80% of cases are acute self limiting with a full
thought to be of immune origin. recovery within 6 months, most within 8 weeks.

Incidence
Commonest cause of thrombocytopenia. Chronic idiopathic thrombocytopenia
purpura
Age
Definition
More common in childhood, peak onset 2–10 years.
Chronic idiopathic thrombocytopenia purpura (ITP) is
a fall in platelet count thought to be of immune origin.
Sex
M = F
Age
Aetiology Chronic ITP is seen predominantly in adults.
The cause is largely not understood but it may arise
1–4 weeks after a viral infection. Platelet associated IgG Sex
antibodies are detectable in the serum of patients. F > M

Pathophysiology Aetiology/pathophysiology
The autoantibody binds to circulating platelets, which Chronic ITP may occur with other autoimmune disor-
are then removed in the spleen. Clinical problems only ders such as systemic lupus erythematosus and thyroid
become apparent when the platelet count falls below disease. Platelet associated IgG antibodies are often de-
9
50 × 10 per litre. tectable.
Clinical features
Clinical features
Children present with petechiae and superficial bruis-
Patients present with easy bruising, purpura, epistaxis
ing, however in severe cases mucosal bleeds occur such
and menorrhagia.
as epistaxis and menorrhagia. Cerebral haemorrhages
are rare. There may be a history of a viral illness in the
previous four weeks. Investigations
Full blood count and blood film identify the low platelet
Investigations count, a bone marrow aspirate demonstrates normal or
Full blood count shows the level of platelets. Bone mar- raised megakaryocytes.
row aspiration can be used to confirm the diagnosis
(normal megakaryocytes) and exclude haematological Management
malignancy. Prednisolone may produce a complete or partial remis-
sion. Intravenous immunoglobulin works by blocking
Management the Fc receptors in the spleen. The effect is transient
Treatment is often not necessary. Steroids and intra- but is useful in severe bleeding and predicts the poten-
venous immunoglobulin (acts by saturating the Fc re- tial success of splenectomy. Other drugs used include