Injecting under pressure: the pain of low CSF pressure headache responsive to botulinum toxin injections.

Low intracranial pressure headaches can, at times, be refractory to treatment including multiple blood patches and preventative medications. Imaging studies are often unable to demonstrate a cerebrospinal fluid leak that is causing headache and other associated symptoms. Onabotulinum toxin A (BTX) injection is a treatment that has proven efficacy for the treatment of chronic migraine and potentially other headache disorders. We report a patient with a long standing history of refractory low pressure headaches with brain imaging that demonstrated brain sag, and no CSF leak could be identified. She received no sustained benefit from numerous blood patches, and was unresponsive or intolerant to multiple preventative medications. With BTX treatment, the patient continued to have daily headaches, but her pain intensity improved from an average 7/10 to 3/10. This benefit has been sustained over 7 years. This case suggests that BTX may be an effective treatment for headaches due to low intracranial pressure. It also suggests that the beneficial effects of BTX in the treatment of headaches occur through a direct modulation of the nociceptive system rather than merely induction of pericranial muscle relaxation.