What are the symptoms? Headache is the most common symptom in IIH, occurring in 90 per cent of patients with this condition. It is most severe in mornings and worsens with coughing or sneezing. Visual disturbance is reported in 35 to 80 per cent of IIH patients and includes: temporary vision loss or ‘blacking out’gradual vision reductionperipheral vision lossdouble vision. These episodes can occur without the patient realising and may not be totally eliminated even with successful treatment of IIH. Other symptoms of IIH include dizziness, nausea and tinnitus. What are the causes? True benign intracranial hypertension means that there is no underlying cause but the many other possible causes of similar conditions need to be excluded. There is an association with medications given for various conditions including tetracyclin, istotretinoin, trimethoprim, sametadine, lithium, naradoxic acid and tamoxifen. If symptoms of benign intracranial hypertension develop in the presence of these medications, then they should be stopped if possible. The patient themself can help the situation by weight loss and it is reported that simply by losing weight, the symptoms can be resolved spontaneously. How is it diagnosed? The following tests are used to diagnose IIH: brain scan (computed tomography scan (CT)/magnetic resonance imaging (MRI)); these should be normaleye examinationlumbar puncture (a process in which CSF is removed from the lower back). How is it treated? IIH is monitored closely through outpatient examinations, which include regular visual testing. Headache diaries are helpful in monitoring. If an underlying cause of IIH is identified, its treatment will usually control IIH. Excess weight will need addressing and loosing seven to ten per cent of body weight may improve headaches and vision. Weight loss should be achieved through a dietician-lead calorie-controlled diet plus exercise. When there is no clear cause, IIH can be treated through lumbar punctures, medicines or surgery. Lumbar puncture involves draining CSF from the lower back, thus reducing ICP. A lumbar puncture is performed under local or general anaesthetic, usually general anaesthetic for children. Intermittent lumbar puncture to reduce pressure is usually an effective treatment for IIH. Treatment with acetazolamide reduces CSF production and thus reduces ICP. Other dehydrating medicines, such as furosemide, can be tried but are less effective. Steroids can also be tried as alternative. When lumbar puncture or drug therapies are unsuccessful or when vision is deteriorating, surgical treatment will be considered. Shunts (a tube draining CSF from the brain or spine into the abdomen) can be used to reduce ICP and there are many different types available. A subtemporal decompression, a technique whereby a ‘window’ is made in the side of the skull thus reducing ICP, can also be performed. Optic nerve fenestration or decompression is another surgical option. In this procedure, slits or a large hole are placed in the optic nerve sheath and fluid drains out, thereby taking pressure off the optic nerve and preventing sight loss. Inheritance patterns and prenatal diagnosis Inheritance patternsIIH is not inherited, but may occur in families. Prenatal diagnosisNot applicable. Is there support? Idiopathic Intracranial Hypertension (IIH) UK Email: email@example.comWebsite: iih.org.uk IIH UK is a Registered Charity in England and Wales No. 1143522. It provides information and support to sufferers, their families and friends. It has an online support forum and holds regional social gatherings. Group details last updated August 2014. Information and support in the UK for idiopathic intracranial hypertension is also provided by SHINE (Spina Bifida•Hydrocephalus•Information•Networking•Equality; see entry Spina Bifida).