Diagnóstico de la hemorragia subaracnoidea espontánea de escasa cuantía o de larga evolución: a propósito de un caso

subarachnoid hemorrhage implies the presence of blood within the subarachnoid space from some pathologic process. the initial study of choice is an urgent cranial computed tomography scan, but its sensitivity declines with time. so that it is recommended that patients with severe sudden headache but normal cranial computed tomography scan, should have a lumbar puncture performed, more than 12 hours after the onset of symptoms, to rule out subarachnoid hemorrhage. the methods for distinguishing among traumatic lumbar puncture and true subarachnoid hemorrhage include the erythrocyte level, the "three tube test", d-dimer assay and ferritin in cerebrospinal fluid. but the best technique is the xanthochromia o yellow-to-orange cerebrospinal fluid supernatant, measured spectrographically. we report a case of a young woman with a subarachnoid hemorrhage diagnosed by xanthochromia after 18 days after the onset of bleeding.