Benign intracranial hypertension

Benign Intracranial Hypertension

Benign Intracranial Hypertension (BIH), also known as Idiopathic Intracranial Hypertension (IIH) or pseudotumor cerebri, is a neurological disorder characterized by increased intracranial pressure (ICP) without an identifiable cause. This condition predominantly affects young, overweight women of childbearing age, but it can occur in other populations as well.

Pathophysiology

The exact pathophysiology of BIH is not well understood. It is hypothesized that there is an imbalance between the production and absorption of cerebrospinal fluid (CSF), leading to increased pressure within the skull. This pressure can compress the brain and optic nerves, potentially leading to vision problems and other neurological symptoms.

Clinical Presentation

Patients with BIH typically present with symptoms of increased intracranial pressure, including:

• Headache: Often described as a throbbing or pressure-like headache, which may be worse in the morning or when lying down.
• Papilledema: Swelling of the optic disc due to increased ICP, which can be observed during an eye examination.
• Transient visual obscurations: Temporary episodes of vision loss or blurring.
• Tinnitus: Often described as a "whooshing" sound in the ears, synchronous with the heartbeat.
• Diplopia: Double vision due to cranial nerve VI palsy.

Diagnosis

The diagnosis of BIH is primarily clinical, supported by imaging and lumbar puncture findings. Key diagnostic criteria include:

• Normal brain imaging (e.g., MRI or CT scan) without evidence of a mass lesion or hydrocephalus.
• Elevated opening pressure on lumbar puncture, typically greater than 250 mm H2O.
• Normal CSF composition.

Management

The management of BIH focuses on reducing intracranial pressure and alleviating symptoms. Treatment options include:

• Weight loss: Often recommended for overweight patients, as it can significantly reduce symptoms.
• Medications: Acetazolamide is commonly used to decrease CSF production. Other diuretics like furosemide may also be used.
• Surgical interventions: In cases where medical management is insufficient, procedures such as optic nerve sheath fenestration or cerebrospinal fluid shunting may be considered.

Prognosis

The prognosis for patients with BIH varies. While many patients experience symptom relief with treatment, some may have persistent symptoms or complications such as vision loss. Regular monitoring by healthcare professionals is essential to manage the condition effectively.

Also see

• Intracranial pressure
• Cerebrospinal fluid
• Papilledema
• Optic nerve