Idiopathic intracranial hypertension (IIH) is a common condition in obese women, leading to significant visual impairment. The cause of IIH is unknown, and management is controversial due to the lack of prospective trials. This thesis provides a comprehensive review of the aetiology and management of IIH. The hypothesis that IIH is associated with a pro-inflammatory cytokine profile, suggested by its association with female gender and obesity, was tested. Laboratory studies demonstrated elevated leptin in the cerebrospinal fluid of women with IIH, suggesting a role in the pathogenesis of IIH. The first randomised controlled trial in IIH is reported, examining treatment with acetazolamide in 50 patients, providing seminal information for future trials and data on the natural history of the condition. A composite scoring system was developed based on clinical parameters, with visual fields and optic disc appearance having the greatest influence on clinical outcome. A systematic study of papilloedema in IIH highlights the limitations of the widely adopted Frisen staging scheme. The thesis also discusses the epidemiology, clinical features, associated factors, and management of IIH, including the role of obesity, cytokine profiles, and the impact of various conditions and medications. The study concludes that IIH is more common in women, predominantly affects younger adults, and is associated with obesity. The management of IIH includes therapeutic lumbar puncture, medication, and surgery, with weight reduction being an important factor. The thesis emphasizes the need for further research into the pathogenesis and optimal management of IIH.Idiopathic intracranial hypertension (IIH) is a common condition in obese women, leading to significant visual impairment. The cause of IIH is unknown, and management is controversial due to the lack of prospective trials. This thesis provides a comprehensive review of the aetiology and management of IIH. The hypothesis that IIH is associated with a pro-inflammatory cytokine profile, suggested by its association with female gender and obesity, was tested. Laboratory studies demonstrated elevated leptin in the cerebrospinal fluid of women with IIH, suggesting a role in the pathogenesis of IIH. The first randomised controlled trial in IIH is reported, examining treatment with acetazolamide in 50 patients, providing seminal information for future trials and data on the natural history of the condition. A composite scoring system was developed based on clinical parameters, with visual fields and optic disc appearance having the greatest influence on clinical outcome. A systematic study of papilloedema in IIH highlights the limitations of the widely adopted Frisen staging scheme. The thesis also discusses the epidemiology, clinical features, associated factors, and management of IIH, including the role of obesity, cytokine profiles, and the impact of various conditions and medications. The study concludes that IIH is more common in women, predominantly affects younger adults, and is associated with obesity. The management of IIH includes therapeutic lumbar puncture, medication, and surgery, with weight reduction being an important factor. The thesis emphasizes the need for further research into the pathogenesis and optimal management of IIH.