A woman in her mid to late 70s who had previously received a diagnosis of immune thrombocytopenic purpura was admitted to the hospital with disturbed activity, ataxic gait, and subacute onset of apathy. She had severe disturbance of consciousness with quadriplegia and global dysphagia, and her National Institutes of Health Stroke Scale score was 28 (range, 0-42, with 0 indicating no stroke symptom and 21-42 indicating severe stroke).She had severe thrombocytopenia (platelet count, <5 × 103/μL [to convert to ×109 per liter, multiply by 1.0]) right before hospitalization. Computed tomography of her brain revealed bleeding throughout the brain (Figure, A-C). Susceptibility weighted imaging with 3-T magnetic resonance imaging revealed abundant microbleeds and macrobleeds in the lobar area in particular. These bleeds included lesions that were visible and lesions that were invisible to computed tomography (Figure, D-F). Cerebral spinal fluid analysis revealed a remarkable decrease in the Aβ40 level (929 pg/mL; mean [SD] level, 4003 [1185] pg/mL) and in the Aβ40/Aβ42 ratio (1.56; mean [SD] ratio, 4.91 [1.13]).1 Thus, the radiological and biochemical findings suggested underlying arteriopathy related to cerebral amyloid angiopathy (CAA), albeit combined with some hypertensive arteriopathy. The administration of high doses of corticosteroids and γ-globulin rapidly brought her platelet count back to normal levels. Notably, she also quickly regained her consciousness, and she was discharged from the hospital a month later, with no neurological deficits; her National Institutes of Health Stroke Scale score was 0. For 2 years after being discharged, her platelet count was maintained at the level of 10 to 20 × 103/μL, and the numbers of microbleeds and macrobleeds detected by use of susceptibility weighted imaging with 3-T magnetic resonance imaging have not increased.
一個近80歲老年女性，既往免疫性血小板減少性紫癜病史。本次是因為活動障礙，步態不穩，亞急性的淡漠入院。她有意識障礙，四肢癱瘓以及嚴重的吞咽困難，NIHSS評分為28分（評分範圍，0-42分，0分代表沒有中風症狀，21-42分代表具有嚴重的中風）。她入院前有嚴重的血小板減少(血小板計數, <5×103/μL [換算為109/L，×1])。CT頭顱平掃提示顱內多處出血病灶 (圖, A-C)。3-T MRI頭顱磁敏感成像提示多處微出血和大血腫，尤其是在皮層區域。這些出血在頭顱CT平掃上有些是可見的，有些是不可見的 (圖, D-F)。腦脊液檢測提示Aβ40 的水平顯著下降（929pg/ml；正常人群均數[標準差]是4003pg/ml[1185pg/ml]），而Aβ40/Aβ42的比例也顯著下降 (1.56; 正常人群均數[標準差]是4.91[1.13])。因此，影像學以及生化指標均提示是與腦澱粉樣變相關（CAA）的血管病，雖然可能合併有高血壓相關的血管病變。大劑量的激素以及丙種球蛋白使得患者的血小板迅速恢復正常。值得注意的是，她的意識狀態也迅速地恢復，一個月後病人出院了，沒有任何神經功能缺損，NIHSS評分為0分。在病人出院2年後複診，她的血小板維持在10 至 20 × 103/μL的水平，磁敏感頭顱MRI成像顯示患者的微出血以及血腫的數量較前沒有增多。
A CT小腦水平 B CT中腦水平 C CT側腦室水平
D SWI小腦水平 E SWI中腦水平 F SWI側腦室水平
圖：在患者入院後第三天接受了3.0T磁共振掃描（機器型號：MAGNETOM TrioTim; Siemens）。磁敏感成像使用如下參數：TR 27ms，TE 20ms，層厚 3 mm，間隙寬度0mm。
It is well known that spontaneous cerebral macrobleeds or microbleeds vary in terms of pathology depending on their anatomical location; those that occur in deep or infratentorial regions are characterized by hypertensive microangiopathy, whereas those that strictly occur in lobar areas are associated with CAA.2 Her multiple cerebral microbleeds were characterized by a myriad of fresh and chronic bleeds with neurological symptoms of subacute onset. They might be 「domino-style cerebral bleeds,」2 which occur when bleeding from 1 ruptured small vessel causes secondary bleeding in other small vessels.
自發性的顱內血腫或者微出血的出血位置根據出血的病因不同，也表現各異。發生在顱腦深部或者幕下區域的腦微出血主要與高血壓小血管病變有關，而僅發生在皮層部位的腦出血可能與血管澱粉樣變性有關。此例病人臨床表現為亞急性起病，影像上多發腦微出血包括了新鮮出血灶和陳舊性出血灶，稱之為「多米諾模式的腦出血」，即一個破裂的小血管引起的腦出血繼發性地導致其他小血管破裂出血。
Neurons secrete Aβ, and some of it is trapped in the cerebral vasculature before drainage. Cerebral amyloid angiopathy is characterized by increased vascular deposition and decreased Aβ level since rebral spinal fluid, the major isoform of which is Aβ40.1Therefore, the decreases in the Aβ40 level and in the Aβ40/Aβ42 ratio in her cerebral spinal fluid suggest that her lobar-dominant cerebral microbleeds were characterized by CAA in addition to immune thrombocytopenic purpura, although the association of CAA and immune thrombocytopenic purpura remains to be elucidated. Although the incidence of intracerebral hemorrhage in patients with immune thrombocytopenic purpura is believed to be only 1% to 2%,3 the accompanying inflammatory endothelial damage and thrombosis due to CAA could induce domino-style multiple macrobleeds or microbleeds, similar to what was observed in a case of paroxysmal cold hemoglobinuria.4 The fact that corticosteroids and γ-globulin dramatically ameliorated her condition supports this hypothesis.
神經元分泌Aβ，有些Aβ被阻止在脈管系統中而不能分泌。腦澱粉樣血管病表現為Aβ在血管內沉積增多而腦脊液中的Aβ減少。Aβ40是Aβ的主要亞型。因此，除了患有血小板減少性紫癜外，腦脊液中Aβ40以及Aβ40/ Aβ42的下降提示該患者的腦葉出血與CAA相關，雖然CAA和免疫性血小板減少性紫癜的相關性仍然有待於進一步的研究。但是，免疫性血小板減少性紫癜的發生腦出血的概率僅為1%至2%，其伴隨的由CAA所致的炎性內皮損傷和血栓會導致多米諾模式的多發血腫或者微出血，類似於陣發性冷性血紅蛋白尿症。事實上，糖皮質激素以及丙種球蛋白明顯減輕病人的病情可以支持這個假設。
(全文終)
編輯：李會琪
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