Context: An empty sella is a relatively common condition, often being an incidental finding at MRI or CT scan. It can develop because of the intrasellar herniation of Cerebro-spinal Fluid (CSF) and arachnoid membrane through an absent or rudimentary diaphragm sellae in concomitance of a sudden and even transient increment of intracranial pressure, leading to a picture in which the pituitary is flattened along the floor of the sella.
Case Description: A young female with headache, nausea, dizziness, diplopia and visual impairment showed an empty sella on MRI and increased CSF pressure at the lumbar puncture. After an initial improvement, there was a progressive worsening of the headache, especially in orthostatic position, with transient relief after bed rest and hydration. At MRI the empty sella was no longer evident, cerebellar tonsils were displaced in the occipital foramen and there was an impregnation of the meninges after contrast medium, a picture of CSF hypotension, probably due to the previously performed lumbar puncture causing a fistula with leak of CSF and consequent disappearance of the empty sella. The patient gradually improved after being submitted to epidural blood patch.
Conclusions: The case here reported demonstrates that an empty sella can be a reversible condition in rare cases. Its disappearance can be due to the reduction in intracranial pressure caused by the lumbar puncture itself. The changes in the characteristics of the headache, in particular its worsening in the orthostatic position, should lead to the suspicion of CSF leak through a fistula and consequent intracranial hypotension, a dangerous and sometimes life-threatening condition.