Main study concluded before enrollment

The purpose of this optional sub-study to GSPB-2018 (NCT03652714) is to evaluate the changes in cerebral blood flow (CBF) under different conditions to understand if postdural puncture headache is caused by changes in the cerebral blood flow and if treatment normalises that change.

Study Population:

Subjects who have consented to participate in GSPB-2018 will be approached for participation in this sub-study. Subjects who have consented to participate in GSPB-2018 are not required to participate in this sub-study.

Inclusion Criteria:

• Age > 18 years
• Patients with postdural puncture headache defined as moderate to severe postural headache (VAS >= 30mm) after lumbar puncture or accidental dural puncture during epidural insertion with an onset within 3 days following the puncture.
• Lack of headache remission within 1 day after dural puncture and after treatment with fluids, caffeine and paracetamol
• Patients who have given their written informed consent for participation in the study and substudy after fully understanding the protocol content and limitations.

Exclusion Criteria:

• Patients who cannot cooperate to the study
• Patients who does not understand or speak Danish
• Allergy to the drugs used in the study
• Has taken opioids within 12 hours prior to intervention
• No possible transcranial window on transcranial doppler. If not possible to find a useable window to get measurement the patient will be excluded and replaced with another patient.