Onyalai.
Onyalai is an acquired form of immune thrombocytopenia which differs clinically, epidemiologically and immunologically from idiopathic thrombocytopenic purpura (Table 4). The clinical hallmark is haemorrhagic bullae on the mucosa of the oronasopharynx. Haemorrhage from ruptured bullae, epistaxis or gastrointestinal bleeding is severe and may cause shock and death. The disease is limited to some black populations of central southern Africa, with a recorded incidence of one per 660 inhabitants per year in the Kavango territory of Namibia. The majority of patients demonstrate both IgG and IgM serum platelet antibodies and serum platelet glycoprotein IIb/IIIa autoantibodies. Chronic thrombocytopenia often ensues and recurrent episodes of clinical bleeding are common. Treatment directed at the prevention of haemorrhagic shock reduced the mortality rate in the acute phase from 9.8 to 2.8%. Standard dose prednisolone does not increase the platelet count. Vincristine sulphate may benefit some patients and splenectomy is indicated in patients with severe uncontrollable haemorrhage. High dose intravenous gammaglobulin may be followed by a rise in the platelet count and cessation of haemorrhage. The aetiology is unknown. The possible aetiological role of mycotoxins from contaminated millet, sorghum or maize requires further investigation.
Hesseling
P B
PB
D000349:Africa; D000367:Age Factors; D001768:Blister / Q000209:etiology; D005260:Female; D006470:Hemorrhage / Q000209:etiology; D006801:Humans; D008297:Male; D009055:Mouth; D009092:Mucous Membrane; D009305:Nasopharynx; D011696:Purpura, Thrombocytopenic / Q000453:epidemiology / Q000209:etiology / Q000628:therapy; D012737:Sex Factors