Siderosis and Subarachnoid Hemorrhage

To the Editor.— In the article by Caroscio et al (Archives1980;357:101-103), a patient with recurrent subarachnoid hemorrhage from a spinal cord arteriovenous malformation associated with an aneurysm had intracranial signs of double vision, slurred speech, and unsteady gait. Initially intermittent, these signs subsequently became fixed, with persistent nystagmus and ataxia. A search for an intracranial source of these signs was unrevealing. Although the authors recognized that intracranial symptoms and signs in spinal subarachnoid hemorrhage are common, no explanation for their occurrence is given. The presence of sustained intracranial signs after repeated subarachnoid hemorrhage may on occasion be the result of superficial siderosis of the CNS. This entity was first observed by Hamill 1 in 1908, and described in clinical detail by Bauer 2 in 1928. Koeppen and Barron 3 and others have shown that the condition occurs as a result of blood in the subarachnoid space. In contrast to