Idiopathic intracranial hypertension (IIH), also known as pseudotumor cerebri or benign intracranial hypertension (BIH), is a disorder characterized by chronically elevated intracranial pressure and signs and symptoms resulting from the raised intracranial pressure in the absence of any detectable underlying causative lesion or pathology.
The presenting features are :
Pharmacologic therapy :
Surgical approach :
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 .
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 .
In absence of obesity, other risk factors associated with idiopathic intracranial hypertension are:
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 .
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 .
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 . 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 . 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.