My pa is one mask of brooses both blue and green. CHARLES DICKENS (1812–1870), NICHOLAS NICKLEBY
Many people present with the complaint that they bruise easily but only a minority turn out to have an underlying blood disorder. Purpura is bleeding into the skin or mucous membranes, appearing as multiple small haemorrhages that do not blanch on pressure. Smaller purpuric lesions that are 2 mm or less in diameter (pinhead size) are termed petechiae, while larger purpuric lesions are called ecchymoses (see FIG. 29.1).
Purpuric rash (petechiae and ecchymoses)
Bruises are large areas of bleeding that result from subcutaneous bleeding. If bruising is abnormal and out of proportion to the offending trauma, then a disturbance of haemostasis is suggested (see FIG. 29.2). The three spontaneous, intrinsically linked pathways that arrest bleeding following injury are vasoconstriction, formation of a platelet plug and activation of coagulation factors.
Photo courtesy Hatem Salem
Severe bleeding in a woman with diabetes and systemic fibrinolysis. Note the bleeding following insulin injections into the abdominal wall and an injection into the shoulder joint.
‘Palpable purpura’ due to an underlying systemic vasculitis is an important differential problem. The petechiae are raised so finger palpation is important. The cause is an underlying vasculitis affecting small vessels (e.g. polyarteritis nodosa).
The decision as to which individuals require investigation is difficult and depends on whether the haemostatic defect is due to local or systemic pathology.1 The ability to identify a bleeding disorder is important because of implications for surgery, pregnancy, medication and genetic counselling.
Key facts and checkpoints
Purpura = petechiae + ecchymoses.
Abnormal bleeding is basically the result of disorders of (1) the platelet, (2) the coagulation mechanism or (3) the blood vessel.
There is no substitute for a good history in the assessment of bleeding disorders.
The first step is an assessment of personal and family histories.
When someone describes ‘bruising easily’ it is important to exclude thrombocytopenia due to bone marrow disease and clotting factor deficiencies such as haemophilia.
The commonest cause of an acquired bleeding disorder is drug therapy (e.g. aspirin, NSAIDs, cytotoxics and oral anticoagulants).
Bleeding secondary to platelet defects is usually spontaneous, associated with a petechial rash and occurs immediately after trauma or a cut wound.1 The bleeding is usually mucosal (e.g. bleeding from gingiva, menorrhagia, epistaxis and petechiae).
Bleeding caused by coagulation factor deficiency is usually traumatic and delayed (e.g. haemorrhage occurring 24 hours after a dental extraction in haemophilia).
Laboratory assessment should be guided by the clinical impression.
The routine screening tests for the investigation of a true bleeding disorder can occasionally be ...