The presenting features are [8]:

• Headache: The most common symptom, almost universally present. It is generalized, throbbing, worse on waking, and aggravated by factors which temporarily increase cerebrospinal fluid pressure such as straining, coughing, or changing posture. 50 % of patients complain of nausea.
• Obesity: Up to 90 per cent of patients are overweight.
• Papilledema: Universally present. Fundus examination of every patient with headache is vital.
• Visual symptoms: Visual obscurations, persistent blurring, or scotomas are reported by 30 to 70 % of patients. Washed out vision, halos and flickering lights lasting for a few seconds may be present. Excess straining and posture change can provoke obscurations, but they can also occur spontaneously. Occasionally, sudden and permanent loss of vision results from infarction of the optic nerve. About 30 per cent of patients complain of horizontal diplopia due to sixth nerve palsy, which may be bilateral. The cause is a false localizing sign of raised intracranial pressure.

• Visual assessment: Visual acuity, color vision, motility assessment and fundus examination
• Visual field: The most common defects are enlargement of the blind spots, generalized constriction of the fields, and scotomas caused by optic nerve damage. There may be a predilection for visual field loss in the inferior nasal quadrants. 
• Fundus fluorescein angiography: Is necessary if fundus examination is not equivocal for diagnosis of papilledema.
• Radiology: For detecting underlying pathology and especially ruling out mass lesions and hydrocephalus before doing lumbar puncture. Computed tomography (CT) scanning shows small and slit-like cerebral ventricles which may increase in volume as intracranial hypertension resolves. A similar appearance is seen on magnetic resonance imaging (MRI). Sagittal sinus thrombosis may be visualized on CT scanning as the characteristic 'empty delta' sign due to clot within the sinus. MRI is superior to CT and provides graphic images of sinus thrombosis. Occasionally MR or CT angiography may be needed to exclude sinus thrombosis or conventional venography if thrombolytic therapy is contemplated.
• Lumbar puncture: To acquire CSF sample, to measure CSF pressure and establish presence of raised pressure. At lumbar puncture the opening pressure is greater than 200 mm cerebrospinal fluid. In simple obesity the cerebrospinal fluid pressure may be as high as 250 mm; therefore the diagnostic significance of cerebrospinal fluid pressure must therefore be correlated with the clinical picture. In the few patients whose cerebrospinal fluid pressure is equivocal, continuous monitoring may demonstrate intermittent peaks of raised pressure.
• Cerebrospinal fluid analysis: The composition of the cerebrospinal fluid is entirely normal, and the presence of white cells or a raised protein concentration cast serious doubt on the diagnosis. CSF is analyzed for white blood cell and differential counts, red blood cell count, glucose, total protein, quantitative protein electrophoresis, microbial microscopy and culture for aerobic bacteria and acid-fast bacilli, cytology, cryptococcal antigens, and syphilis markers.
• Blood analysis: Complete blood count, serum iron and iron-binding capacity, erythrocyte sedimentation rate, procoagulant profile (in patients with a previous history of thrombosis or MRI evidence of dural venous sinus occlusion on MRI), antinuclear antigen (ANA) profile (e.g. anti-dsDNA and anti-ssDNA), Lyme screening test if the history is suggestive.

Weight loss is strongly recommended with exercise regime and diet management.

Pharmacologic therapy [9]:

• Acetazolamide and furosemide
• Amitriptyline or propranolol for the prophylaxis of headache
• Corticosteroids are added in case of inflammatory etiology

Surgical approach [10]:

• If visual function continues to deteriorate, optic nerve sheath fenestration (decompression), lumboperitoneal or ventriculoperitoneal shunts to divert cerebrospinal fluid and intracranial venous sinus stenting may be attempted.

Idiopathic intracranial hypertension does not increase the mortality risk. The papilledema may lead to irreversible optic neuropathy with accompanying constriction of the visual field and loss of color vision. Prolonged papilledema can adversely affect the central visual acuity as well. Timely diagnosis and treatment can preserve vision [7].

In the majority of patients with idiopathic intracranial hypertension, no cause can be identified. The most commonly affected patients are obese young women. A higher body mass indexes (BMIs) and recent weight gain is associated with the increased risk, but the causative mechanisms are not clear. Pregnancy and menstrual irregularity are also risk factors [2].

In absence of obesity, other risk factors associated with idiopathic intracranial hypertension are:

• Drugs: Exposure or withdrawal of certain exogenous substances, like corticosteroids, vitamin A (> 100,000 U/day)/retinoic acid, antibiotics, carbidopa, levodopa, amiodarone, indomethacin, levonorgestrel implants, oral contraceptives, cyclosporine, danazol, growth hormone, lithium, and phenytoin.
• Systemic diseases: Anemia, chronic respiratory insufficiency, hypertension, multiple sclerosis, Lyme disease, psittacosis, chronic renal disease, thrombocytopenic purpura, sarcoidosis, systemic lupus erythematosus and Reye syndrome.
• Disruption of cerebral venous flow: An impaired absorption of cerebrospinal fluid (CSF) may result from any compression of cerebral veins (extravascular tumors, secondary thrombosis due to coagulopathy) or a venous flow anomaly.
• Preceding minor head injury has shown some association.
• It has been suggested that an empty sella may be associated with about 4 % of cases. There is raised intracranial pressure in combination with incompetence of the diaphragm sellae. Clinical hypopituitarism does not occur, but occasionally the empty sella may harbor a prolactinoma [3].

The incidence of idiopathic intracranial hypertension in the United States has been estimated to range from 0.9 to 1.0 per 100,000 in the general population. The female preponderance over males ranges from 3:1 to 8:1. The incidence in women is 1.6-3.5 per 100,000 overall, with an incidence of 7.9-20 per 100,000 in overweight women of childbearing age (17 to 44 years). Very rarely, it is familial and may occur in more than one generation. Although men have a lower incidence, they are twice as likely as women to lose visual function as a result of papilledema [4].

The mechanism by which intracranial pressure rises is poorly understood and the contribution of various factors controversial. Since the intracranial contents are housed in a rigid container, an increase in cerebrospinal fluid pressure in theory may result from an increase in blood volume, swelling of the brain parenchyma, or an increase in the cerebrospinal fluid volume due to overproduction or malabsorption. However, there is little evidence to suggest that increased blood volume or cerebrospinal fluid production have any causative role [5].

Although idiopathic intracranial hypertension occurs more in overweight women, the role of obesity is not clear. In some cases, a familial link between obesity and idiopathic intracranial hypertension has been documented. Obesity may increase intraabdominal pressure leading to raised cardiac filling pressures. This may result in impeded venous return from the brain [6]. The increased intracranial pressure interrupts the axoplasmic flow of the optic nerves giving rise to papilledema which may lead to irreversible optic neuropathy.

Obesity is strongly correlated to idiopathic intracranial hypertension and therefore, weight management can contribute to prevention of this condition in many people. A high index of suspicion in overweight women and pregnant women complaining of visual disturbance is important for timely diagnosis and management.

Idiopathic intracranial hypertension (IIH), also known as pseudotumor cerebri or benign intracranial hypertension (BIH), is a syndrome of raised intracranial pressure occurring in the absence of an intracranial mass lesion or enlargement of the cerebral ventricles due to hydrocephalus. The condition occurs predominantly in obese women of childbearing age. The chronically elevated intracranial pressure leads to symptoms of headache and visual loss, with papilledema, which may lead to progressive optic atrophy and blindness [1]. It was previously called benign intracranial hypertension but the term is not preferred anymore because of the significant morbidity associated with the condition.

Definition: Idiopathic intracranial hypertension, also known as pseudotumor cerebri, is a condition in which the pressure of the fluid inside the skull is increased leading to damage to the optic nerves.

Cause: The cause is unknown, however, it occurs more in overweight women, pregnancy, and is associated with deficiency and excess of vitamin A, and some other drugs, inflammatory conditions and infectious diseases.

Symptoms: Headache, nausea, washed out vision with loss of vividness of colors and transient obscuration of vision is common. Headache may be mild to severe, and may increase with bending or coughing.

Diagnosis: Vision is tested and the presence of increased cerebrospinal fluid pressure is established by examining the optic nerve at the back of the eye with an instrument called ophthalmoscope and by examining the fluid pressure with a needle inserted in the lower part of the spine in the back.

Treatment and follow-up: Weight reduction is an important aspect of treatment of this condition. Medications are given to reduce the intracranial pressure. If the raised pressure does not respond to medication and the optic nerve is in danger of permanent damage, surgery may be done to reduce the pressure in the skull and within the optic nerve.

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