New insights in idiopathic intracranial hypertension 

The Guest Lecture at the Neurology Update Meeting 2025 was delivered by Prof Alexandra Sinclair, Professor of Neurology, University of Birmingham, UK, and lead of the Translational Brain Science Research Group.

The title of the lecture was ‘Idiopathic intracranial hypertension (IIH): New insights shaping clinical practice’.

Prof Sinclair gave an overview of IIH, including risk factors, clinical features, investigations and management, including during pregnancy.

The condition, which is most common in women of reproductive age, results in raised intracranial pressure (ICP) in the brain and can cause disabling headaches and loss of sight due to the compression of the optic nerve (papilloedema).

Prof Sinclair said that papilloedema is a common presenting sign, although it is not always straightforward to recognise. For example, Prof Sinclair noted that pseudopapilledema is an eye condition where the optic disc appears elevated, mimicking papilloedema, but without the swelling caused by increased ICP.

She quoted evidence which showed approximately 40 per cent of patients labelled with IIH who are referred to a neuro-ophthalmology clinic do not have the condition.

“Error is due to the inaccurate identification of papilloedema,” she added.

Patients with IIH may also suffer from other symptoms that include pulsatile tinnitus, back pain, dizziness, neck pain, visual blurring, cognitive disturbances, radicular pain, and horizontal diplopia.

Prof Sinclair pointed out intracranial hypertension can be the result of secondary causes.

A careful history is required to rule out drug-induced intracranial hypertension, she said.

“Drug-induced intracranial hypertension can only be confirmed if the drug is withdrawn and the intracranial hypertension resolves,” according to Prof Sinclair.

Obstructive sleep apnoea (OSA) is a common comorbidity, she said, referencing a study she was involved in which found an OSA prevalence of 47 per cent in an IIH cohort.

IIH is also “strongly associated with obesity”, she told the meeting, noting that the condition is increasing in parallel with obesity rates.

In terms of treating obesity, Prof Sinclair referred to how dieting is “very poor at lasting weight loss”.

She stressed that achieving sustained weight loss is vital as it is “disease-modifying” in IIH. Those with a higher baseline weight needed to lose more weight, according to a study published in Neurology in 2022, titled ‘Association of amount of weight lost after bariatric surgery with intracranial pressure in women with idiopathic intracranial hypertension’.

In terms of what type of bariatric surgery to choose, the study found Roux-en-Y gastric bypass achieved greater, more rapid, and sustained ICP reduction compared with other methods.

Weight loss drugs are another option, with growing evidence about their potential benefits, Prof Sinclair said.

A randomised clinical trial on the effect of the GLP-1 RA (receptor agonist) exenatide on IIH was published in the journal Brain in 2023. It found a significant reduction in ICP in patients with IIH, with the GLP-1 RA also treating their obesity.

Prof Sinclair also highlighted data which found tirzepatide is the most effective GLP-1 RA, leading to 15 per cent weight loss by six months and 19-20 per cent weight loss by 12 months (New England Journal of Medicine, 2022).

Speaking to the Medical Independent (MI) after her lecture Prof Sinclair said: “Ten years ago, we had no evidence base on how to treat IIH effectively. We hadn’t proven it was related to weight…. We have now proved conclusively that losing weight is disease-modifying.”

In her talk, she also discussed how there is now a greater understanding of headaches associated with IIH.

“We know they are migraine-like, and that is something we didn’t know 10 years ago,” she told MI. “And we know now that we can use migraine-therapies to treat those patients.”

In terms of the future, Prof Sinclair said ensuring access to treatments is essential, in addition to continuing to expand the evidence base.

Prof Sinclair is the Chief Investigator of the new IIH-Advance Study, which will evaluate the effect of weight loss induced by tirzepatide plus standard of care over six months in patients diagnosed with IIH compared to standard of care only on proportion with resolution of papilloedema.

Another study Prof Sinclair is leading is the IIH Intervention trial. This is comparing cerebrospinal fluid shunting with dural venous sinus stenting in IIH patients with sight-threatening papilloedema.

Both interventions reduce intracranial pressure and preserve vision, but there has been no direct comparison between them, and it is currently not known which one is more effective.