Читать книгу Pathy's Principles and Practice of Geriatric Medicine - Группа авторов - Страница 583

In these disorders (Table 24.4), coagulation tests and platelet number and function are normal. The defect lies in the vascular endothelium and supporting tissues.¹³ Senile purpura is relatively common and occurs on the extensor surfaces of the forearms and hands in particular. It is due to decreased amounts of collagen supporting the small blood vessels, which rupture with minor trauma or apparently spontaneously. The process is considerably accelerated by long‐term treatment with corticosteroids. There is no specific treatment and, other than being cosmetically disturbing, it does not constitute a significant haemorrhagic diathesis. Hereditary haemorrhagic telangiectasia is an autosomally dominantly inherited disease with multiple telangiectasia of the lips, conjunctiva, and oral cavity associated with telangiectasia throughout the gastrointestinal tract and also with pulmonary arteriovenous malformations. The condition tends to become progressively more severe with age and frequently presents in later life, usually as chronic iron deficiency anaemia. Troublesome gastrointestinal bleeding can usually be managed by iron supplementation but may require a chronic transfusion regimen. The fibrinolytic inhibitor tranexamic acid and oestrogens have been used with some success. Owing to the widespread nature of the lesions, surgery is not usually a feasible treatment option.¹⁴

Table 24.4 Haemorrhagic vascular defects.

Senile purpura

Steroid purpura

Hereditary haemorrhagic telangiectasia

Gastrointestinal angiodysplasia

Ehlers–Danlos syndrome

Henoch–Schönlein purpura

Scurvy (vitamin C deficiency) is associated with purpura and widespread bleeding, particularly from mucosal surfaces and subperiostally. It is due to both abnormal collagen synthesis and a defect in platelet function but is rare in the Western world, except in association with malnutrition and alcoholism. Amyloidosis may be primary or complicate paraproteinaemias, collagen vascular disorders, and chronic infection. The deposition of amyloid protein in the blood vessels leads to fragility, and consequently purpura is common. Cases of a specific coagulation defect due to absorption of the coagulation factor X by the amyloid protein have occasionally been reported. Ehlers–Danlos syndrome, especially type IV with a deficiency of type III collagen, results in structural weakness of major blood vessels with a tendency to rupture and consequent severe haemorrhage. Henoch–Schönlein purpura is rare in the elderly, being primarily a condition of childhood. It is an anaphylactoid purpura with cutaneous petechia and urticaria, associated with joint swelling, abdominal colic, and melena. Despite the purpura, which is usually a manifestation of severe thrombocytopenia, the platelet count remains normal in this condition. Precipitating drugs should be withdrawn; steroids give relief from the joint and abdominal symptoms.