Pathophysiology and Treatment of Cerebrospinal Hypotension Exploration Study

Inclusion Criteria (patients): * Age 18-80. * Patients with a suspected intracranial hypotension diagnosis. * Participants must read and understand the Danish language or have an official interpreter present to be able to understand the work-up and sign the participation consent for the study. Inclusion Criteria (Control): * Age 18-80. * Healthy people who do not suffer from any form of primary headache except infrequent tension-type headache. * Participants must read and understand the Danish language or have an official interpreter present to be able to sign the participation consent for the study. Exclusion Criteria (patients): * Pregnant or breastfeeding females * Patients in whom the examination cannot be performed due to anatomical reasons such as severe head dysmorphia or severe ophthalmological diseases. * The patient has a disease, takes medication, or abuses alcohol or drugs that could, in the investigator´s opinion interfere with the assessments of safety, tolerability, or efficacy, or interfere with the conduct or interpretation of the study. * The patient is, in the investigator´s opinion, unlikely to comply with the protocol or is unsuitable for any reason. Exclusion Criteria (Control): * Pregnant or breastfeeding females * Participants in whom the examination cannot be performed due to anatomical reasons such as severe head dysmorphia or severe ophthalmological diseases. * The participant has a disease, takes medication, or abuses alcohol or drugs that could, in the investigator´s opinion interfere with the interpretation of the study.