Which investigations are essential for confirming a diagnosis of idiopathic intracranial hypertension in primary care?

Essential investigations to confirm idiopathic intracranial hypertension (IIH) in primary care include:

• Neuroimaging: Urgent brain imaging, preferably MRI with venography, is essential to exclude secondary causes of raised intracranial pressure such as venous sinus thrombosis or mass lesions. CT head may be used if MRI is not immediately available, but MRI is preferred for detailed assessment NICE CG150[Mollan et al. 2018].
• Ophthalmic assessment: A thorough fundoscopic examination to detect papilloedema is critical, as IIH diagnosis requires evidence of raised intracranial pressure manifesting as optic disc swelling NICE CG150[Mollan et al. 2018].
• Lumbar puncture (LP): Measurement of opening cerebrospinal fluid (CSF) pressure via LP is necessary to confirm raised intracranial pressure after neuroimaging has excluded mass lesions or venous thrombosis. CSF analysis also excludes infection or other secondary causes NICE CG150[Mollan et al. 2018].
• Clinical assessment: Detailed history and neurological examination to identify symptoms and signs consistent with IIH (e.g., headache, visual disturbances) and to exclude other neurological deficits or red flags that require urgent referral NICE CG150.

In primary care, the role is to identify suspected IIH based on symptoms and signs, perform initial assessment including blood pressure and neurological examination, and urgently refer for neuroimaging and specialist ophthalmology assessment. Definitive diagnosis requires specialist investigations including LP under controlled conditions NICE CG150[Mollan et al. 2018].