Optic nerve changes in raised intracranial pressure

Abstract

Papilledema and widened optic nerve sheaths are common findings in chronically elevated intracranial pressure (ICP) and are often encountered in e.g. benign intracranial hypertension (Aulhorn 1984). It has been proven experimentally that both phenomena are closely linked (Hayreh 1984) because perineural cerebrospinal fluid (CSF) pressure depends on intracranial subarachnoidal pressure. This is applied in clinical practice when surgical optic nerve sheath decompression helps to resolve papilledema and prevent blindness. Since papilledema is a rather late finding in patients with raised intracranial pressure, we investigated the behaviour of the optic nerve sheath in patients under neurological intensive care. This retrobulbar structure, concealed for clinical examination, can be imaged by B-scan ultrasound which is applicable at bedside in the intensive care unit (ICU). In particular, we adressed the question of the temporal sequence of changes of the nerve sheath and head.