Page 350 - Essential Haematology

336 / Chapter 25 Bleeding disorders

Diagnosis 4 Monoclonal antibody Rituximab (anti - CD20)
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1 The platelet count is usually 10 – 100 × 10 /L. produces responses in approximately 50%, which

The haemoglobin concentration and white cell are often durable and it is now usually tried
count are typically normal unless there is iron before splenectomy.

deficiency anaemia because of blood loss. 5 Thrombopoietin - receptor agonists Romi plostim

2 The blood film shows reduced numbers of plate- (subcutaneously) and eltrombopag (orally) are

lets, those present often being large. There are no active non - peptide thrombopoietin - receptor ago-
morphological abnormalities in the other cell nists (thrombomimetics) (Fig. 25.4 ). Th ey stim-
lines. ulate thrombopoiesis (Fig. 25.5 ). Th ey are

3 The bone marrow shows normal or increased indicated for patients in whom steroids are con-
numbers of megakaryocytes. traindicated or who are refractory to steroids.
4 Sensitive tests are able to demonstrate specifi c 6 Splenectomy This operation was recommended

antiglycoprotein GPIIb/IIIa or GPIb antibodies in patients who have symptoms and still have
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on the platelet surface or in the serum in most platelets < 30 × 10 /L after 3 months of steroid
patients. Platelet - associated IgG assays are less therapy or who require unacceptably high doses

specifi c. These tests are not usually used in of steroids to maintain a platelet count above
clinical practice. 30 × 10 /L. With the increase in number of
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alternative drugs, splenectomy is now performed
Treatment
As this is a chronic disease the aim of treatment less frequently for ITP than previously. Good
should be to maintain a platelet count above the results occur in most of the patients, but in
level at which spontaneous bruising or bleeding patients with ITP refractory to steroids or immu-
occurs with the minimum of intervention. In noglobulin there may be little benefi t. Splenunculi
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general, a platelet count above 50 × 10 /L does not must be removed otherwise subsequent relapse of
require treatment. ITP can occur.
7 Other treatments that may elicit a remission
1 Corticosteroids Eighty per cent of patients remit include danazol (an androgen which may cause
on high - dose corticosteroid therapy. Prednisolone virilization in women) and intravenous anti - D

1 mg/kg/day is the usual initial therapy in adults immunoglobulin. It is often necessary to combine
and the dosage is gradually reduced after 10 – 14 two drugs (e.g. danazol and an immunosuppres-
days. In poor responders the dosage is reduced sive agent). Helicobacter pylori infection should
more slowly but alternative immunosuppression be treated as there are some reports that this may
or splenectomy is considered. improve the platelet count.
2 High dose intravenous immunoglobulin 8 Platelet transfusions Platelet concentrates are
therapy is able to produce a rapid rise in platelet beneficial in patients with acute life - threatening

count in the majority of patients. A regimen of bleeding. Th eir benefit will only last a few hours.

400 mg/kg/day for 5 days or 1 g/kg/day for 2 days 9 Stem cell transplatation has cured some severe

is recommended. It is particularly useful in cases.
patients with life - threatening haemorrhage, in
steroid - refractory ITP, during pregnancy or prior Acute i diopathic t hrombocytopenic p urpura

to surgery. The mechanism of action may be This is most common in children. In approximately

blockage of Fc receptors on macrophages or 75% of patients the episode follows vaccination or
modification of autoantibody production. an infection such as chickenpox or infectious mono-

3 Immunosuppressive drugs (e.g. vincristine, nucleosis. Most cases are caused by non - specifi c
cyclophosphamide, azathioprine, mycophenolate immune complex attachments to platelets.
mofetil or ciclosporin alone or in combination) Spontaneous remissions are usual but in 5 – 10% of
are usually reserved for those patients who do not cases the disease becomes chronic (lasting > 6

respond sufficiently to steroids, rituximab or months). Fortunately, morbidity and mortality in
splenectomy. acute ITP is very low.