Fluctuation of intra-parenchymal cerebral pressure may drive the rapid spontaneous resolution of acute subdural hematoma.

Acute subdural hematoma (ASDH) is a severe insult with a high mortality rate, and emergent surgical evacuation is recommended in the vast majority of such cases. Generally, resolution of the hemorrhage requires weeks and months in patients treated conservatively. However, numerous cases of rapid spontaneous resolution of ASDH, occurring within 72h after the trauma, have been reported to date in the literature. Several possible hypotheses have been suggested, primarily involving redistribution and dilution, or washing out the ASDH. In this study, we present the relevant images of such a case, review the mechanisms of the rapid spontaneous resolution in the literature, and also propose a new hypothesis to explain the occurrence of the rapid spontaneous resolution of ASDH. We indicate that the fluctuation of intra-parenchymal cerebral pressure that drives the rapid spontaneous resolution of ASDH.