When does a patient have intracranial hypotension?

Cerebrospinal fluid is made in the brain ventricles which goes out of the brain beneath the cerebellum to the spinal cord and the nerves and then comes back to the brain. The brain and the spinal cord are surrounded by the membrane called dura and the movement of CSF from the brain to the spinal cord and vice versa is made through the dura membrane.
If there is any leakage in the dura membrane, the cerebrospinal fluid present in it seeps out of the membrane which ultimately results in the dislocation of the brain and causes the condition called intracranial hypotension. It is commonly seen after the brain surgery, spinal cord surgery. But sometimes, the CSF may leak out of the dura spontaneously, without any injury is called as spontaneous intracranial hypotension. This is mainly caused due the weakened dura and is very difficult to detect at the earlier stage.