Rung giãn nhãn cầu ở trẻ sơ sinh có thể khó phát hiện. Mặc dù sự khởi đầu có thể được sinh ra nhưng nó có thể được phát hiện sau này. Các hình thức phổ biến là gật đầu spasmus và rung giãn nhãn cầu bẩm sinh. Các tính năng phân biệt thông thường được cung cấp trong bảng dưới đây. | 378 Chapter 11 3 Albinism Albinism is a genetically determined abnormality in melanin synthesis that is associated with congenital nystagmus foveal hypoplasia and impaired visual acuity. The ocular fundus can be totally devoid of pigment or have a blond appearance. The degree of visual impairment is usually inversely related to the degree of ocular pigmentation. 4 Compressive lesions Craniopharyngiomas Optic nerve or chiasmatic gliomas - associated with neurofibromatosis. 5 Hereditary optic atrophies Nystagmus in infants Nystagmus in infants can be difficult to detect. Although the onset may be at birth but it can be detected later. The common forms are spasmus nutans and congenital nystagmus. The common distinguishing features are provided in the table below. Spasmus nutans is a self-limited disorder of infants characterized by a slow cephalic tremor associated with pendular horizontal and rarely vertical nystagmus that is often monocular. Abnormal head positions are frequently present. Optic nerve and chiasmatic gliomas can simulate spasmus nutans. Therefore neuroimaging should always be obtained in such cases. Features Spasmus nutans Congenital nystagmus Age of onset 4 months-3 years Birth Family history Negative Positive or negative Nystagmus Asymmetric 30 unilateral Bilateral and symmetric Head movement Usually previous to nystagmus Simultaneous with nystagmus Natural history Disappears in 36 months Usually persists Other Guidelines for the determination of brain death in children The guidelines for determination of brain death in children are similar to adults although they have some unique features dealing specifically with the age group from full-term newborn to the 5-year-old. Pediatric Neurology 379 These features are mainly focused on longer periods of recommended observation relative to the patient s age as outlined below. 1 Coma and apnea must co-exist. 2 Absence of brainstem function Pupils unreactive to light midposition or dilated . Absence
