During the consent process, she expresses concern about a post-LP headache. What is the mechanism of post-LP headaches?

A 23-year-old woman undergoes a planned lumbar puncture (LP) as part of neurological investigations for possible multiple sclerosis. During the consent process, she expresses concern about a post-LP headache. What is the mechanism of post-LP headaches?

Vertebral body injury
Nerve injury
Bleeding into cerebrospinal fluid
Leaking cerebrospinal fluid from the dura
Too much cerebrospinal fluid removed

Dr. Kasper:
Leaking cerebrospinal fluid from the dura

Leaking of cerebrospinal fluid from the dura is the most likely explanation for post-lumbar puncture headaches. It is thought that ongoing leak of cerebrospinal fluid (CSF) through the puncture site causes ongoing CSF loss, leading to low pressure. A post-LP headache is typically frontal or occipital and occurs within three days. It is normally associated with worsening on standing and improvement when lying down. Treatment in severe cases includes an epidural blood patch, but most resolve on their own.

Vertebral body injury, nerve injury and bleeding would not cause headaches, whilst the loss of cerebrospinal fluid volume during lumbar puncture does not cause pain.