Deresiewicz R L, Thaler S J, Hsu L, Zamani A A
Infectious Disease Division, Brigham and Women's Hospital and Harvard Medical School, Boston, USA.
N Engl J Med. 1997 Jun 26;336(26):1867-74. doi: 10.1056/NEJM199706263362604.
Eastern equine encephalitis occurs principally along the east and Gulf coasts of the United States. Recognition of the neuroradiographic manifestations of eastern equine encephalitis could hasten the diagnosis of the illness and speed the response to index cases.
We reviewed all cases of eastern equine encephalitis reported in the United States between 1988 and 1994. The records of 36 patients were studied, along with 57 computed tomographic (CT) scans and 23 magnetic resonance imaging (MRI) scans from 33 patients.
The mortality rate was 36 percent, and 35 percent of the survivors were moderately or severely disabled. Neuroradiographic abnormalities were common and best visualized by MRI. Among the patients for whom MRI scans were available, the results were abnormal for all eight comatose patients as well as for all three noncomatose patients who subsequently became comatose. The CT results were abnormal in 21 of 32 patients with readable scans. The abnormal findings included focal lesions in the basal ganglia (found in 71 percent of patients on MRI, and in 56 percent on CT), thalami (found in 71 percent on MRI and in 25 percent on CT), and brain stem (found in 43 percent on MRI and in 9 percent on CT). Cortical lesions, meningeal enhancement, and periventricular white-matter changes were less common. The presence of large radiographic lesions did not predict a poor outcome, but either high cerebrospinal fluid white-cell counts or severe hyponatremia did.
Eastern equine encephalitis produces focal radiographic signs. The characteristic early involvement of the basal ganglia and thalami distinguish this illness from herpes simplex encephalitis. MRI is a sensitive technique to identify the characteristic early radiographic manifestations of this viral encephalitis.
东部马脑炎主要发生在美国东部和墨西哥湾沿岸。认识东部马脑炎的神经影像学表现有助于加快疾病诊断并加速对首例病例的应对。
我们回顾了1988年至1994年间美国报告的所有东部马脑炎病例。研究了36例患者的记录，以及来自33例患者的57份计算机断层扫描（CT）和23份磁共振成像（MRI）扫描结果。
死亡率为36%，35%的幸存者有中度或重度残疾。神经影像学异常很常见，MRI显示效果最佳。在有MRI扫描结果的患者中，所有8例昏迷患者以及随后昏迷的3例非昏迷患者结果均异常。在32例有可读扫描结果的患者中，21例CT结果异常。异常表现包括基底节局灶性病变（MRI检查中71%的患者出现，CT检查中56%的患者出现）、丘脑（MRI检查中71%的患者出现，CT检查中25%的患者出现）和脑干（MRI检查中43%的患者出现，CT检查中9%的患者出现）。皮质病变、脑膜强化和脑室周围白质改变较少见。影像学上大的病变的出现并不能预测预后不良，但脑脊液白细胞计数高或严重低钠血症则可以。
东部马脑炎产生局灶性影像学征象。基底节和丘脑的特征性早期受累将本病与单纯疱疹病毒性脑炎区分开来。MRI是识别这种病毒性脑炎特征性早期影像学表现的敏感技术。
