小白馬

作者：Pam Harrison  
出處：WebMD醫學新聞

　　April 28, 2010 — 根據一篇由西班牙研究團隊進行的文獻回顧，查加斯氏疾病，一種由寄生蟲Trypanosoma cruzi造成的疾病，是缺血性中風一個獨立危險因子，且許多病患並不知道他們被感染了，直到他們發生中風。
　　
　　西班牙巴塞隆納昆卡Virgen de la Luz醫院的Francisco Javier Carod-Artal醫師與醫院診所的Joaquim Gascon醫師引用一項研究，其中高達42%罹患查加斯氏疾病患者持續有缺血性中風，且在中風後才診斷遭到感染（J Neurol Sci. 2007;263:35-39）。
　　
　　他們表示，很少有研究數據顯示感染Trypanosoma cruzi後病患的累積風險。這項綜論於4月14日線上發表於5月號的Lancet神經學期刊上。
　　
　　【篩檢中風患者】
　　在一項有輕微查加斯氏心臟病變的患者群體中，大約有1.2%病患在第一年的後續追蹤中發生缺血性中風（Acta Cardiol. 2000;55:33-38），在平均後續追蹤的36個月之間，另一組213位罹患查加斯氏疾病且左心室收縮功能不全的患者中，整體缺血性中風發生率為每100位病患每年2.7件（J Neurol Sci. 2009;278:96-101）。
　　
　　研究作者們附帶表示，中風是無症狀或慢性疾病查加斯氏疾病的第一個病徵，不論其心臟收縮功能或是否有心律不整。且罹患查加斯氏疾病，但沒有相關血管危險因子或是心臟衰竭臨床證據的患者，也處於中風風險。
　　
　　研究作者們建議，有鑑於此，如果中風患者居住於流行區域，或從流行區域搬來，應該接受Trypanosoma cruzi的篩檢。
　　
　　【查加斯氏心臟病變】
　　研究作者們指出，查加斯氏心臟病變與缺血性中風獨立有關，且其特徵為出現鬱血性心臟衰竭、許多種類的心律不整、傳導阻滯、突發性心跳停止以及全身性栓塞。
　　
　　他們附帶表示，與查加斯氏中風有關的主要危險因子包括心尖動脈瘤、心律不整、心壁栓塞、以及左心室功能不全。然而，約有70%罹患查加斯氏中風患者有心電圖上的異常。
　　
　　至少一篇斷面性研究（J Neurol Neurosurg Psychiatry. 2003;74:516-518）指出，相反的，典型的危險因子，如糖尿病、吸菸，在查加斯氏疾病患者身上，相較於沒有這種疾病患者少見。
　　
　　研究作者們指出，沒有專一的或是神經症狀可以區分查加斯氏中風與其他心因栓塞性中風成因。感染Trypanosoma cruzi的中風患者，應該根據中風治療指引進行急性中風治療與次級預防。
　　
　　據估計中風再發率約20%，而心因性查加斯氏中風次級預防包括長期抗凝血藥物。需要臨床研究來評估查加斯氏疾病患者長期使用口服抗凝血藥物於原發與次發性中風預防的效果。
　　
　　他們附帶表示，最後，查加斯氏疾病、中風及血管性失憶症風險之間的關聯目前仍未被適當地研究，且並沒有研究評估再發性查加斯氏感染對於血管性失智症的效應。雖然部分研究已經報告慢性Trypanosoma cruzi感染與以迷你精神狀態評估（MMSE）的認知功能受損關係，仍然需要進一步的研究來證實其相關性。
　　
　　研究作者們預測，遷徙模式的改變，包括從拉丁美洲的移民，可能導致美國與歐洲Trypanosoma cruzi感染病例增加。
　　
　　研究作者們表示沒有相關資金上的往來。


Parasitic Chagas Disease a Growing Cause of Ischemic Stroke

By Pam Harrison
Medscape Medical News

April 28, 2010 — Chagas disease, caused by the parasite Trypanosoma cruzi, is an independent risk factor for ischemic stroke, and many patients are unaware they are infected until after they have their first stroke, according to a new review of the literature by Spanish investigators.

Francisco Javier Carod-Artal, MD, Hospital Virgen de la Luz, Cuenca, and Joaquim Gascon, MD, Hospital Clinic, Barcelona, Spain, cite 1 study in which 42% of patients with Chagas disease who had sustained an ischemic stroke were diagnosed with the infection after they had had their stroke (J Neurol Sci. 2007;263:35-39).

"Few data are available on the cumulative risk of stroke in people with T cruzi infection," they note. The review is published online April 14 and will appear in the May issue of The Lancet Neurology.

Screen Stroke Patients

In 1 cohort of patients with mild chagasic cardiomyopathy, approximately 1.2% of patients had an ischemic stroke during the first year of follow-up (Acta Cardiol. 2000;55:33-38). At a mean follow-up of 36 months, another group of 213 patients with Chagas disease and left ventricular systolic dysfunction showed an overall incidence of ischemic stroke of 2.7 events per 100 patient-years (J Neurol Sci. 2009;278:96-101).

"Stroke could be the first sign of Chagas disease in patients with asymptomatic or chronic disease, irrespective of systolic dysfunction or presence of cardiac arrhythmias," the study authors add, "and patients with Chagas disease but without associated vascular risk factors or clinical evidence of heart failure could also be at risk of stroke."

In light of this, stroke patients should be screened for T cruzi infection if they reside in or have emigrated from endemic regions, the study authors suggest.

Chagasic Cardiomyopathy

Chagasic cardiomyopathy is independently associated with ischemic stroke, the study authors point out, and is characterized by the presence of congestive heart failure, several types of arrhythmias, conduction defects, sudden cardiac death, and systemic thromboembolism.

"The main risk factors associated with chagasic stroke include cardiac apical aneurysm, arrhythmias, mural thrombus, and left ventricular dysfunction," they add, whereas about 70% of patients with chagasic stroke have electrocardiographic abnormalities.

In contrast, classic risk factors, such as hypertension, diabetes, and smoking, are less common in stroke patients with Chagas disease than in those without, at least according to 1 cross-sectional study (J Neurol Neurosurg Psychiatry. 2003;74:516-518).

"No specific signs or neurological symptoms can distinguish chagasic stroke from other causes of cardioembolic stroke," the study authors note. In stroke patients with T cruzi infection, treatment of acute stroke and secondary prevention measures should be done according to stroke guidelines, they add.

It is estimated that stroke recurrence occurs in approximately 20% of patients and secondary prevention measures include long-term anticoagulation in cardioembolic chagasic stroke. "Clinical trials are needed to assess the efficacy of long-term oral anticoagulation in primary and secondary prevention of stroke in Chagas disease," they conclude.

Finally, the association among Chagas disease, stroke, and the risk for vascular dementia has not been "properly investigated," they add, and there are no studies assessing the effect of recurrent chagasic infection on vascular dementia. "Although some studies have reported an association between chronic T cruzi infection and cognitive impairment, as measured by the Mini-Mental State Examination, further studies are needed to prove this link."

Changes in migration patterns, including emigration from Latin America, could lead to a substantial disease burden from T cruzi infection in the United States and in Europe, the study authors predict.

The study authors have disclosed no financial relationships.

Lancet Neurol. 2010;9:533-542.