Value of Cerebrospinal Fluid (CSF) Biomarkers in Patients of Idiopathic Intracranial Hypertension (IIH) as an Indicative of Visual Affection and Treatment Modalities

Idiopathic intracranial hypertension (IIH) is a rare disease of increasing incidence recently[1], owing to the rising curve of obesity and weight gain[2,3]. It is a disease of elevated intracranial pressure without known obvious aetiology. The reported incidence of IIH is 1 to 3 cases per 100,000 people of the general population[4]. IIH is diagnosed by exclusion; as patients come with continuous headache repeated vomiting , pulsatile tinnitus and the hall landmark of this disease, visual disturbance. One of the most deleterious effect of IIH is through its effect on optic nerve (papilledema) leading to visual field defect, horizontal double vision and finally decrease of visual acuity. Despite this, these presentations may not appears collectively and patient can come with one or two of vague symptoms as in IIH without papilledema variant[5]. So IIH needs an accurate, trusted, and rapid tool for diagnosis and follow up. Modified Dandy criteria[6,7] gives an informative description for IIH and a differentiation from other causes of increase intracranial pressure through; Signs and symptoms of increased intracranial pressure, Absence of localizing findings on neurologic examination, Absence of deformity, displacement, or obstruction of the ventricular system except for evidence of increased cerebrospinal fluid pressure (greater than 200 mm water)[8]. Normal neuroimaging except for empty sella turcica, optic nerve sheath with filled out CSF spaces, and smooth-walled non flow-related venous sinus stenosis or collapse should lead to another diagnosis, No other cause of increased intracranial pressure present for CSF opening pressure of 200 to 250 mm water.

The clinical presentation of the disease is heterogeneous and often not correlating with the objective findings such as lumbar puncture opening pressure and papilledema. Currently, it is not possible to predict if a patient will respond to medical treatment, or which patients may develop severe permanent visual loss. Papilledema, the only non-invasive objective measurable treatment response, develops with substantial delay compared to intracranial pressure. Therefore, an objective tool indicating permanent optic nerve damage is sorely needed and will help guide treatment and predicting disease outcome. Biomarkers have this advantage as they allow early predicting optic nerve damage. For that reason CSF biomarkers deserve precise understanding for there rule in IIH which is the aim of our study.