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The outstanding causes are senile purpura and purpura due to steroids.5 The cause in both instances is atrophy of the vascular supporting tissue.
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Simple purpura (easy bruising syndrome)
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This is a benign disorder occurring in otherwise healthy women usually in their 20s or 30s. The feature is bruising on the arms, leg and trunk with minor trauma. The patient may complain of heavy periods. Major challenges to the haemostatic mechanism, such as dental extraction, childbirth and surgery, have not been complicated by excessive blood loss.
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Unexplained bruising or bleeding may represent self-inflicted abuse or abuse by others. In self-inflicted abuse, the bruising is commonly on the legs or areas within easy reach of the patient.
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Immune (idiopathic) thrombocytopenic purpura
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Acute onset in children
Easy bruising and petechiae
Epistaxis, bleeding gums and menorrhagia common
No systemic illness
Splenomegaly rare
Isolated thrombocytopenia: platelets may be <20 000/mm3
Other blood cells normal
Otherwise normal physical examination
Normal bone marrow with normal or increased megakaryocytes (acute leukaemia and aplastic anaemia should be excluded)
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DxT bruising + oral bleeding + epistaxis ➜ ITP
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The two distinct types caused by immune destruction of the platelets are:
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acute thrombocytopenia of childhood—usually in children, usually postviral
chronic ITP—autoimmune disorder, usually in adult women; all cases should be referred to a specialist unit
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Acute thrombocytopenia of childhood
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This is caused by a reaction to a virus infection resulting in the production of cross-reacting antibodies against platelets.
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There is an early risk of spontaneous haemorrhage, so refer/admit to hospital especially if the platelet count is <30 × 109/L or there is active bleeding.
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The prognosis is good, invariably self-limiting—90% resolve in 6 months. It may recur with further viral infections. The rest pass into chronic ITP.
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Bleeding is treated with immunoglobulin or steroids.
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Chronic idiopathic (immune) thrombocytopenic purpura
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Chronic ITP is a relapsing illness that rarely undergoes spontaneous remission and may require treatment with prednisolone or biological agents, e.g. rituximab. Ask about drug history. Some require splenectomy, but this operation is avoided where possible, especially in young children, because of the subsequent risk of severe infection, particularly with Streptococcus pneumoniae.5 (Refer later in this chapter.)
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Thrombotic thrombocytopenic purpura
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This is an uncommon life-threatening syndrome of haemolytic anaemia, thrombocytopenia and extremely high LDH. Clinical features include fever (non-infectious), neurologic and kidney abnormalities. The defect is in the absence of a specific protease in the plasma.
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COAGULATION DISORDERS
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The inherited disorders such as haemophilia A and B are uncommon and involve deficiency of one factor only. The acquired disorders, such as disseminated intravascular coagulation (DIC), occur more commonly and invariably affect several anticoagulation factors (see TABLE 39.6).
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Inherited coagulation disorders
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A list of the inherited bleeding disorders is included in TABLE 39.1. The better-known disorders are vWD, haemophilia A and haemophilia B (Christmas disease).
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von Willebrand disease
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This is the most common disorder of haemostasis (incidence 1% of population) and is usually a mild problem with an excellent prognosis.6 There are about 22 types.
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Autosomal dominant inheritance (common types)
Equal sex incidence
Prolonged bleeding time
Bleeding tendency exacerbated by aspirin
Platelets normal
Defective platelet adhesion at site of trauma combined with factor VIII deficiency6
APTT prolonged
Positive vW factor antigen
Menorrhagia and epistaxis common
Haemarthroses rare
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DxT menorrhagia + bruising + increased bleeding—1. incisions 2. dental 3. mucosal ➜ vWD
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No specific treatment
Avoid aspirin (including Alka-Seltzer), NSAIDs, IM injections
Be cautious of surgical and dental procedures
Preparations that help include desmopressin acetate (DDAVP), factor VIII concentrates and tranexamic acid
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Spontaneous haemarthroses, especially knees, ankles and elbows, are almost pathognomonic
X-linked recessive pattern of inheritance
Invariably only males affected (1 in 5000)
Females theoretically affected if haemophiliac father and carrier mother
The human factor gene has long been identified
Severity levels:
– severe—bleed spontaneously
– moderate—bleed with mild trauma or surgery
– mild—bleed after major trauma or surgery
Deficiency of factor VIII
APTT prolonged
Normal prothrombin time and fibrinogen
Many seropositive for HIV, hepatitis B or C (factor VIII concentrate transmission)
Low platelet count should suspect HIV-associated ITP6
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DxT spontaneous haemarthrosis + muscle bleeds + delayed bleeding ➜ haemophilia A
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Haemophilia B (Christmas disease)
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Identical clinical features to haemophilia A
Also an X-linked recessive hereditary disorder
Incidence of 1 in 30 000
Deficiency of coagulation factor IX
Same laboratory findings as haemophilia A apart from specific factor assays
Treatment is with recombinant factor IX concentrates