Assessment of ICP in Idiopathic Intracranial Hypertension Using Transocular Ultrasound and Transcranial Doppler

This study is a prospective cohort study. Investigators plan to include 50 patients in whom the IIH-diagnosis is suspected. Patients are referred from general practitioners, neurologists or ophthalmologists to the Danish Headache Center or admitted to the Neurology ward when the IIH diagnosis is suspected. As part of an established routine clinical work-up to establish the diagnosis of IIH, all patients will undergo (according to the Friedman criteria) the following examinations: A) 1. An interview (history taking) and clinical examination 2. Routine laboratory tests (blood tests) 3. Ophthalmological examination 4. Lumbar puncture with measurement of the ICP 5. Magnetic resonance imaging (MRI) of the brain Additionally the following investigations will be performed at baseline (before and after lumbar puncture): B) Transorbital sonography (TOS) C) Transcranial Doppler When the patient is seen at the clinic for their regular follow-up visits the same measurements will be done. A control group of healthy participants (NR=25) will be included in whom TOS (B) and TCD (C) will be performed in order to compare the values between the patient group (IIH) and control group. Controls will be included to match the patients according to BMI, age and gender. All ultrasound images- and films will be saved, and evaluated by a blinded investigator.