RESUMEN
OBJECTIVE: Spontaneous intracranial hypotension (SIH) is most commonly caused by cerebrospinal fluid (CSF) leakage. Therefore, we hypothesised that patients with orthostatic headache (OH) would show decreased optic nerve sheath diameter (ONSD) during changes from supine to upright position. METHODS: Transorbital B-mode ultrasound was performed employing a high-frequency transducer for ONSD measurements in the supine and upright positions. Absolute values and changes of ONSD from supine to upright were assessed. Ultrasound was performed in 39 SIH patients, 18 with OH and 21 without OH, and in 39 age-matched control subjects. The control group comprised 20 patients admitted for back surgery without headache or any orthostatic symptoms, and 19 healthy controls. RESULTS: In supine position, mean ONSD (±SD) was similar in patients with (5.38±0.91â mm) or without OH (5.48±0.89â mm; p=0.921). However, in upright position, mean ONSD was different between patients with (4.84±0.99â mm) and without OH (5.53±0.99â mm; p=0.044). Furthermore, the change in ONSD from supine to upright position was significantly greater in SIH patients with OH (-0.53±0.34â mm) than in SIH patients without OH (0.05±0.41â mm; p≤0.001) or in control subjects (0.01±0.38â mm; p≤0.001; area under the curve: 0.874 in receiver operating characteristics analysis). CONCLUSIONS: Symptomatic patients with SIH showed a significant decrease of ONSD, as assessed by ultrasound, when changing from the supine to the upright position. Ultrasound assessment of the ONSD in two positions may be a novel, non-invasive tool for the diagnosis and follow-up of SIH and for elucidating the pathophysiology of SIH.
Asunto(s)
Ecoencefalografía/métodos , Hipotensión Intracraneal/diagnóstico por imagen , Adulto , Anciano , Anciano de 80 o más Años , Pérdida de Líquido Cefalorraquídeo/diagnóstico por imagen , Femenino , Humanos , Hipotensión Ortostática , Masculino , Persona de Mediana Edad , Nervio Óptico/diagnóstico por imagen , Órbita/diagnóstico por imagen , Valores de ReferenciaRESUMEN
Optic nerve sheath diameter (ONSD) sonography is a reliable method for evaluation of intracranial pressure, yet there is a lack of reliable normal values. In the study described here, we established normal ONSD values in three different age groups and both sexes. One hundred eighty-seven volunteers without central nervous system disease were enrolled in this prospective study. ONSD measurements were taken in volunteers in the supine and upright positions and after application of positive end-expiratory pressure (PEEP). Normal ONSD values were 4.9-5.3 mm (patient age range: 20-85), with significant differences between men and women (p < 0.001). ONSD values increased with age (∆â¯=â¯0.34 mm, p < 0.001). There were no differences compared with the upright position but application of PEEP led to significantly increased ONSD values (∆â¯=â¯0.21 mm, pâ¯=â¯0.008). ONSD values increased with age, correlated well with the width of the third ventricle, were significantly lower in the female cohort and quickly responded to PEEP, especially in women.