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 space-occupying lesions. CT head may be used if MRI is not immediately available, but MRI is preferred for detailed assessment. This step is critical before confirming IIH diagnosis NICE CG150[Mollan et al. 2018].
• Ophthalmic assessment: A thorough eye examination including fundoscopy to detect papilloedema is vital. Papilloedema is a hallmark of IIH and its presence supports the diagnosis NICE CG150[Mollan et al. 2018].
• Lumbar puncture (LP): Measurement of opening cerebrospinal fluid (CSF) pressure via lumbar puncture is required to confirm raised intracranial pressure after neuroimaging has excluded other causes. CSF analysis also excludes infection or malignancy. LP should be performed in secondary care but arranging timely referral from primary care is important NICE CG150[Mollan et al. 2018].
• Clinical assessment: Careful history and neurological examination to identify symptoms and signs consistent with IIH (e.g., headache, visual disturbances, pulsatile tinnitus) and to exclude other neurological deficits or red flags that warrant urgent referral NICE CG150.

In primary care, the role is to recognise clinical features suggestive of IIH, perform initial assessment including fundoscopy, and urgently refer for neuroimaging and specialist evaluation including lumbar puncture. Definitive confirmation of IIH requires exclusion of secondary causes by imaging and demonstration of raised CSF pressure, which cannot be done solely in primary care NICE CG150[Mollan et al. 2018].