Thrombotic thrombocytopenic purpura

Thrombotic thrombocytopenic purpura (TTP) is

A rare disorder of early adulthood which, despite the low platelet count, causes recurrent and widespread occlusion of small vessels. The pathophysiology involves microangiopathic haemolysis and formation of platelet microthrombi. TTP may be familial or acquired, but in both cases endothelial cells secrete abnormally large von Willebrand factor multimers; these are not degraded because of the lack of the cleavage enzyme ADAMTS-13. This causes the formation of platelet thrombi in small vessels. The clinical hallmarks are fevers, hepatic and renal disease, and a low platelet count. Fragmented red cells on the blood film, elevated lactate dehydrogenase, bilirubin and reticulocyte count are typical laboratory clues. Fluctuating neurological symptoms of altered conscious level, seizures, headache or encephalopathy may herald disease onset in half of the patients, sometimes provoked by intercurrent illness; and most patients have neurological symptoms at some stage of the illness. Low platelets can lead to intracerebral haemorrhage, but ischaemic stroke from large or small vessel occlusion may occur. The mainstay of treatment is plasma exchange. Antiplatelet agents or anticoagulants are usually used in ischaemic stroke, although evidence for efficacy is lacking. Other immunomodulatory treatments have been used, including ciclosporin and rituximab. Haemophilia, disseminated intravascular coagu-

Malabsorption

About 3 per cent of patients with inflammatory bowel disease, ulcerative colitis or Crohn’s disease have neurological complications, most often a demyelinating peripheral neuropathy. Less commonly, a chronic progressive or acute inflammatory myelopathy may appear: these are more common in Crohn’s disease. Vascular complications associated with inflammatory bowel disease may result from hypercoagulability and include cerebral venous sinus thromboses and ischaemic strokes.


Lation and von Willebrand disease are also rare causes of intracerebral haemorrhage.

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  • Category: Nervous diseases