双语病例——脑弓形虫病

朗读老师：章  维     昆明医科大学第二附属医院

翻译老师：司东雷     石家庄市第三医院

History: A 48-year-old woman presents with subacute weakness that is greater on the right than left, pronator drift, dyspnea on exertion, hypoesthesia of her feet, and dysgeusia.

An unenhanced CT scan was performed. Axial image is shown below.

病史：一位48岁女性，表现为亚急性虚弱，右侧大于左侧，旋前肌漂移，用力时呼吸困难，足部感觉减退，以及味觉障碍。

进行平扫CT扫描。轴向图像如下所示。

MR images

A brain MRI scan was performed. Axial fluid-attenuated inversion-recovery (FLAIR) and axial T1-weighted postcontrast images, as well as an axial apparent diffusion coefficient (ADC) map, are shown below. Click to enlarge.

进行脑部核磁共振扫描。轴位液体衰减反演恢复（FLAIR）和轴位T1加权增强后图像以及轴位表观扩散系数（ADC）图如下所示

Findings

• Head CT: There are multiple areas, including the temporal lobes, of hypoattenuation in the white matter bilaterally consistent with vasogenic edema. There is mild mass effect associated with regions of vasogenic edema. There is mild diffuse sulcal effacement.

结果

·头颅CT：双侧白质有多个区域（包括颞叶）低密度，与血管源性水肿一致。与血管源性水肿相关的区域有轻微的占位效应。轻度弥漫性脑沟消失。

• Head MRI: MRI shows multiple infra- and supratentorial lesions with surrounding vasogenic edema, and many of them have an alternating pattern of hypo- and hyperintense signal on T2-weighted/FLAIR imaging -- i.e., the so-called target pattern of enhancement. There is no evidence of restricted diffusion and no evidence of abnormal meningeal enhancement.

头部MRI：MRI显示多个幕下和幕上病变，周围有血管源性水肿，其中许多在T2加权/FLAIR成像上呈低信号和高信号交替模式，即所谓的增强后靶征。没有证据表明扩散受限，也没有证据表明脑膜异常强化。

Differential diagnosis

• Neurotoxoplasmosis

• Metastatic disease

• Bacterial infection with abscess

• Central nervous system lymphoma

Diagnosis: Neurotoxoplasmosis

鉴别诊断

 脑弓形虫感染

  转移性疾病

 细菌感染伴脓肿

 中枢神经系统淋巴瘤

诊断：脑弓形虫感染

Discussion

Neurotoxoplasmosis

Pathophysiology

Toxoplasma gondii is a parasite that is usually asymptomatic in immunocompetent patients but can reactivate in immunocompromised patients, causing significant morbidity. Symptoms usually occur when CD4 levels drop below 100. Transmission is through ingestion, most commonly cat feces or undercooked infected meat. Once ingested, the parasite enters any nucleated cell, most commonly in the central nervous system; extracerebral toxoplasmosis is less common.

讨论

脑弓形虫感染

病理生理

弓形虫是一种寄生虫，通常在免疫功能正常的患者中无症状，但在免疫功能低下的患者中可重新激活，导致显著的发病率。症状通常发生在CD4水平下降到100以下时。传播是通过摄入，最常见的是猫粪便或未煮熟的感染肉。一旦摄入，寄生虫进入任何有核细胞，最常见的中枢神经系统；脑外弓形虫病不太常见。

Epidemiology

Up to 11% of people in the U.S. and up 80% in parts of Europe, South America, and Africa are infected with Toxoplasma gondii, though the majority are asymptomatic. In the presence of HIV/AIDS, up to 30% of patients not on therapy are symptomatic. Neurotoxoplasmosis is considered an AIDS-defining illness.

流行病学

在美国，高达11%的人和欧洲、南美和非洲部分地区80%的人感染了弓形虫，尽管大多数人没有症状。在存在艾滋病毒/艾滋病的情况下，多达30%的未接受治疗的患者有症状。神经弓形虫病被认为是艾滋病的界定性疾病。

Clinical presentation

Patients typically present with fever and headache, altered mental status, focal neurologic deficits, and seizure. Less commonly, patients present with extracerebral manifestations from disseminated disease, including cough from pneumonitis and eye pain from chorioretinitis.

临床表现

患者通常表现为发热、头痛、精神状态改变、局灶性神经功能缺损和癫痫发作。较少见的是，患者表现为播散性疾病的脑外表现，包括肺炎引起的咳嗽和脉络膜视网膜炎引起的眼痛。

Imaging features

• CT: CT typically shows multiple hypodense regions in the basal ganglia and gray-white junction corresponding to edema from lesion(s) with possible mass effect. If contrast is given, ring enhancement may be seen.
   

• MRI:

• Isointense in T1-weighted imaging

• Concentric hypo- and hyper/isointense rings known as the concentric target sign on T2-weighted imaging

• Surrounding edema on FLAIR

• Ring enhancement on postcontrast imaging

• No specific restricted diffusion
   

• FDG-PET:

• No uptake

• Can be used to differentiate from lymphoma, which shows uptake

影像特征

CT：CT典型显示基底节和灰白质交界处有多个低密度区，与病灶水肿相对应，可能有占位效应。增强后，可以看到环状强化

MRI:在T1加权成像中呈等信号；T2加权成像上同心低信号和高信号/等信号环称为同心靶征

周围水肿

强化后图像环形增强

无弥散受限

         FDG-PET:

  无吸收摄取

    可以用来与淋巴瘤鉴别，淋巴瘤表现为摄取

Treatment

Treatment can be initiated from imaging findings alone and consists of antibiotics. No biopsy is needed. Toxoplasma gondii immunoglobulin G (IgG) serology can be used for additional evidence if needed. Sulfadiazine and pyrimethamine are recommended for initial treatment. Steroids and antiepileptic medications are often given for management of the edema and seizures if present. Following initial therapy, prophylactic therapy with trimethoprim-sulfamethoxazole should be started along with antiretroviral therapy. Prophylactic therapy can be discontinued once CD4 levels have recovered. There is no consensus on whether neuroimaging should be used to guide discontinuation of prophylactic therapy.   

治疗

治疗可以从单独的影像学表现开始，包括抗生素。不需要活检。如果需要，弓形虫免疫球蛋白G（IgG）血清学可用于补充证据。初次治疗建议使用磺胺嘧啶和乙胺嘧啶。类固醇和抗癫痫药物通常用于水肿和癫痫的治疗。在初步治疗后，复方新诺明的预防性治疗应与抗逆转录病毒治疗一起开始。一旦CD4水平恢复，就可以停止预防性治疗。神经影像学是否应该用来指导预防性治疗的中止，目前还没有共识。