急性菌痢的肠道病变及脓血便主要是因为（）

A.痢疾杆菌侵入肠黏膜固有层，引起固有层小血管痉挛，上皮细胞坏死，形成溃疡

B.内毒素引起肠壁坏死

C.外毒素引起肠黏膜坏死

D.迟发型变态反应

E.痢疾杆菌产生的溶组织酶

David, a hyperkinetic 5-year-old, exhibits signs of extreme restlessness, short attention span, and impulsiveness. In order to alter the child’s milieu that would likely be most therapeutic for him, what could the nurse do()

A. Define behaviors of the child that will be acceptable and those that will be unacceptable.

B. Allow the child freedom to choose activities in which to participate and other children with whom to associate.

C. Increase the child’s sensory stimulation and activity.

D. Limit the child’s opportunities to display anger and frustration.