中枢神经系统感染-2课件

1、TUBERCULOUS MENINGITIS,结核性脑膜炎,Longnan Hospital Chenjing,Tuberculous meningitis is an infection of the membranes 膜covering the brain and spinal cord (meninges). Tuberculosis (TB) is caused by the bacterium Mycobacterium tuberculosis结核分枝杆菌 and is annually responsible for nearly two million deaths worldwide. A third of the worlds population is currently infected with the TB bacillus, and more than eight million new cases are diagnosed each year.,Tuberculous meningitis must be considered in patients

2、 who present with a confusional state, especially if there is a history of pulmonary tuberculosis, alcoholism, corticosteroid treatment, HIV infection, or other condition associated with impaired immune responses.,It should also be considered in patients form areas (eg, Asia, Africa) or groups (eg, the homeless and inner-city drug users) with a high incidence of tuberculosis.,Causes,Risk factors include a history of: AIDS Excessive alcohol use Pulmonary tuberculosis Weakened immune system,Pathog

3、enesis & Pathology发病机制&病理,Tuberculous meningitis usually results from reactivation of latent infection with mycobacterium tuberculosis. 结核性脑膜炎多是由于潜伏的结核杆菌复发感染引起的。,Primary infection, typically acquired by inhaling bacillus containing droplets, may be associated with metastatic dissemination of blood-borne bacilli from the lungs to the meninges and surface of the brain. Here the organisms remain in a dormant state in tubercles that can rupture into the subarachnoid space at a later time, resulting

4、in tuberculous meningitis.,原发性感染，尤其是通过吸入含菌颗粒引起的感染，可能与血源性细菌从肺部到脑膜及大脑表面的播散有关。此处的致病菌在结核结节中处于休眠状态，后期可破入蛛网膜下腔，并导致结核菌性脑膜炎。,主要发现是含有大量单核细胞的脑基底部脑膜分泌物。脑膜及脑表面可见结核结节。,The main finding is a basal meningeal exudate渗出物containing primarily mononuclear cells. Tubercles may be seen on the meninges and surfaces of the brain.,The ventricle may be enlarged as a result of hydrocephalus, and their surfaces may show ependymal exudate or granular ependymitis. Arteritis can result in cerebral infarction, and basal inflam

5、mation and fibrosis can compress cranial nerves.,脑积水可引起脑室扩大，并且脑室表面可有大量室管膜渗出物或颗粒状室管膜炎。 动脉炎可导致脑梗塞，而颅底部炎症反应和纤维化可压迫神经。,Acute tuberculous meningitis with marked involvement of the vessel walls and occlusion of smaller vessels. The vascular involvement can result in infarction.,Clinical Findings,A. SYMPTOMS Symptoms have usually been present for less than 4 weeks at the time of presentation and include fever, lethargy昏睡 or confusion, and headache. Weight loss, vomiting, neck stiffness, visual impairme

6、nt, diplopia 复视, focal weakness, and seizures may also occur. A history of contact with known cases of tuberculosis is usually absent.,B.SIGNS,Fever, signs of meningeal irritation脑膜刺激征, and a confusional state are the most common findings on physical examination, but all may be absent. Papilledema视乳头水肿, ocular palsies眼肌麻痹, and hemiparesis轻偏瘫 are sometimes seen.,Complications include spinal subarachnoid block脊髓蛛网膜下腔梗阻, hydrocephalus脑积水, brain edema脑水肿, cranial never palsies颅神经麻痹, and stroke cause

7、d by vasculitis or compression of blood vessels at the base of the brain因血管炎或颅底血管受压导致的卒中.,结核球,stroke,hydrocephalus,Laboratory Findings,Only one-half to two-third of patients show a positive skin test for tuberculosis or evidence of active or healed tubercular infection on chest x-ray.,CSF,The diagnosis is established by CSF analysis. CSF pressure is usually increased, and the fluid is typically clear and colorless but may form a clot upon standing. Lymphocytic and mononuclear cell pleocytosis of

8、 50-500 cells/mL is most often seen, but polymorphonuclear 多形核细胞pleocytosis can occur early and may give an erroneous impression of bacterial meningitis. CSF protein is usually more than 100 mg/dL, particularly in patients with spinal subarachnoid block. The glucose level is usually decreased and may be less than 20 mg/dL.,Acid-fast smears抗酸染色涂片 of CSF should be performed in all cases of suspected tuberculous meningitis , but they are positive in only a minority of cases.,Definitive diagnosis is

9、 most often made by culturing M tuberculosis from the CSF, a process that usually takes several weeks and requires large quantities of spinal fluid for maximum yield.,The polymerase chain reaction (PCR) 聚合酶链反应 has also been used for diagnosis.,Finally, the CT scan may show contrast enhancement of the basal cisterns and cortical meninges, or hydrocephalus.,MRI appearance of the typical pattern of central nervous system tuberculous meningitis,Differential Diagnosis,Many other conditions can a subacute confusional state with mononuclear cell单核细胞 pleocytosis 脑脊液细胞增多, including syphilitic 梅毒的, fungal, neoplastic 肿瘤的, and partially treated bacterial meningitis. These can be diagnosed by appropriate smears 涂片, cultures, and serologic 血清学的 and cytologic examinations 细胞学检查.,Treatment,Treatment should be started as early as possible; it should not be withheld while awaiting culture results. The decision to treat is based on the CSF findings described above; lymphocytic pleocytosis and decreased

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