英语病例（ADEM)

History:  Young adult woman with fever, anorexia, and progressive confusion.

（年轻女性，发热，厌食及进行性精神障碍)

Acute disseminated encephalomyelitis (ADEM)

(急性播散性脑脊髓炎）

ADEM is an autoimmune demyelinating disease（自身免疫性疾病） generally associated with preceding viral infection.  Often there is no history of antecedent infection. Clinically, it is impossible to differentiate this entity from a first attack of multiple sclerosis（多发性硬化）.  However, ADEM is a monophasic illness as opposed to multiple sclerosis, which is polyphasic or progressive by definition.

Several well known viral infections（病毒感染) (e.g., measles(麻疹）, mumps（流行性腮腺炎）, influenza（流感）, etc) are thought to precede the development of ADEM.  Some anti-viral vaccines（病毒疫苗） have also been reported to antedate development of this condition.   The clinical course is highly variable, ranging from a slow progression over weeks to a fulminant course over hours to days.

Neurological signs and symptoms are variable and nonspecific, but evidence of upper motor neuron（上运动神经元） dysfunction is the rule. Headache, meningimus, and altered mental status with confusion progressing to lethargy and coma are common accompaniments. Cranial nerve involvement is common, particularly optic neuritis（视神经炎）. Motor involvement ranges from focal spastic weakness to quadraplegia. Sensory findings are almost always present. Often there is evidence of transverse myelitis（横贯性脊髓炎）.  Cerebellar dysfunction is common and initially may be the only finding.

Laboratory evaluation typically shows a CSF pleocytosis with up to 150-200 WBCs, generally with a lymphocytic（淋巴细胞） predominance. The protein level（蛋白质水平） is usually elevated.

MRI images show multiple white matter lesions on T2 and flair sequences with gadolinium enhancement on T1.  These findings are typical for inflammatory demyelinating lesions, as seen with multiple sclerosis, but they are frequently more confluent and larger in size than typical MS plaques.  Frequently there is uniform enhancement（均匀强化） of lesions (suggesting active disease) unlike MS in which there often is patchy enhancement（斑片状强化） if multiple lesions are present.

Treatment is aimed at suppressing the immune response（抑制免疫应答）. Generally, high dose corticosteroids（糖皮质激素） are administered over 3 to 5 days. Plasma exchange（血浆置换） and intravenous immunoglobulin（静脉注射免疫球蛋白） have been used with some reported benefit.

The prognosis is variable. In mild cases up to  90% of patients completely recover.   In more severe cases mortality may be as high as 5-20%, and up to 50% of these patients are left with some permanent neurological disability（神经功能障碍）.