Pseudotumor cerebri (IIH) and vision

Idiopathic intracranial hypertension (IIH) is a condition characterized by elevated pressure of the cerebrospinal fluid (CSF) that surrounds the brain, optic nerves, and spinal cord. It is termed 'idiopathic' because no underlying cause can be identified after a thorough medical evaluation has ruled out other potential reasons for the increased pressure. This elevated pressure can lead to swelling of the optic nerves, known as papilledema, which, if left untreated, can threaten permanent vision loss.

IIH is more common among young women of childbearing age, especially those who are overweight or obese. Similar raised pressure can also arise from identifiable causes, including certain medicines such as tetracycline antibiotics and vitamin A derivatives such as isotretinoin. When a medication or another cause explains the pressure, it is called secondary intracranial hypertension rather than IIH. Tell the medical team about all medicines and supplements, but do not stop prescribed treatment on your own.

The most common symptom of IIH is headache, which often worsens when lying down, occurs upon waking, or can even awaken individuals from sleep. Other symptoms include transient visual obscurations, which are temporary episodes of blurred or dimmed vision lasting a few seconds, often triggered by changes in posture or bending over. Pulsatile tinnitus (a whooshing sound in the ears that synchronizes with the heartbeat) and double vision (diplopia) for distant objects can also occur. In advanced stages, permanent vision impairment may develop. These symptoms are not exclusive to IIH and warrant medical evaluation.

Diagnosing IIH requires confirming raised pressure and excluding other causes. Assessment includes visual acuity, visual fields and examination of the optic discs, often supported by OCT to document swelling. Brain imaging with MRI, or CT when appropriate, is combined with imaging of the cerebral veins such as MRV or CTV to exclude a mass and venous sinus thrombosis. After imaging has excluded a contraindication and the doctor has assessed safety, lumbar puncture is usually needed to measure the opening pressure and check the composition of the cerebrospinal fluid. OCT alone cannot establish the diagnosis, and the results must be interpreted together.

The primary goals of IIH treatment are to protect vision and manage symptoms. Initial treatment often involves medications that reduce CSF production, such as acetazolamide. Weight loss, especially for patients who are overweight or obese, is a critical component of management and can significantly help in controlling the disease and preventing exacerbations. In some cases, when medication and weight management are insufficient, surgical intervention may be considered.

When vision is threatened, surgery may be needed urgently rather than waiting for medication or weight changes to work. Options include optic nerve sheath fenestration, which creates an opening in the sheath around the optic nerve to reduce pressure there, or a shunt that drains cerebrospinal fluid from the brain's ventricles or the space around the spinal cord, usually to the abdomen. Venous sinus stenting may be considered in carefully selected patients after specialist assessment of a relevant narrowing and its pressure effect. These procedures have different risks and goals, and the choice is individualized; surgery is not routinely used for headache alone.

Patients with IIH require regular medical follow up to monitor their vision and assess the effectiveness of treatment. Adherence to prescribed medications and maintaining a healthy lifestyle are important. Urgent medical attention should be sought for any progressive or sudden decline in vision, significant worsening of headaches, or the development of new neurological symptoms. These changes could indicate an exacerbation of the condition requiring immediate intervention to prevent further complications.