What are the causes, treatment, and diagnostics of Idiopathic Intracranial Hypertension (IIH), also known as Pseudotumor Cerebri?

From the Guidelines

Pseudotumor cerebri, also known as idiopathic intracranial hypertension (IIH), should be managed with a focus on treating the underlying disease, protecting vision, and minimizing headache morbidity, as outlined in the consensus guidelines on management 1. The main causes of IIH include obesity, certain medications, endocrine disorders, and systemic diseases like lupus.

Diagnosis and Symptoms

Diagnosis involves a thorough neurological examination, brain imaging (MRI or CT) to rule out other causes, and a lumbar puncture showing elevated opening pressure with normal cerebrospinal fluid composition 1. The hallmark symptoms include:

• Headaches
• Pulsatile tinnitus
• Transient visual obscurations
• Papilledema (swelling of the optic disc)

Treatment

Treatment focuses on reducing intracranial pressure and preventing vision loss. First-line medication is acetazolamide (Diamox) starting at 500mg twice daily, potentially increasing to 1000-2000mg daily as tolerated. Topiramate (25-50mg twice daily) can be used as an alternative due to its weight loss properties and pressure-lowering effects. Weight loss of 5-10% is strongly recommended for overweight patients 1. For rapidly deteriorating vision or medication-resistant cases, surgical interventions include optic nerve sheath fenestration or cerebrospinal fluid shunting procedures. Regular ophthalmologic monitoring with visual field testing is essential to track disease progression and treatment response. Patients should be advised to discontinue medications that may exacerbate the condition and maintain adequate hydration while taking carbonic anhydrase inhibitors to prevent kidney stones. The overall management of IIH should follow the principles outlined in the consensus guidelines, which emphasize the importance of interdisciplinary collaboration and patient-centered care 1.

From the Research

Causes of Pseudotumor Cerebri

• The exact cause of pseudotumor cerebri, also known as idiopathic intracranial hypertension (IIH), is unknown 2, 3, 4, 5, 6
• However, several factors have been associated with the condition, including:
  • Obesity 3, 4, 5, 6
  • Hypervitaminosis A and related compounds 3
  • Steroid withdrawal 3
  • Female gender 3

Symptoms of Pseudotumor Cerebri

• Common symptoms of IIH include:
  • Headaches 2, 3, 4, 5, 6
  • Visual loss 2, 3, 4, 5, 6
  • Pulsatile tinnitus 2, 3
  • Papilledema 3, 4, 5
  • Diplopia from sixth nerve paresis 3

Diagnosis of Pseudotumor Cerebri

• IIH is a diagnosis of exclusion, and other causes of increased intracranial pressure must be ruled out through history, imaging, and cerebrospinal fluid examination 4
• Formal visual field testing is important to determine the severity and time course of symptoms and visual loss 4

Treatment of Pseudotumor Cerebri

• The main goals of treatment are alleviation of symptoms, including headache, and preservation of vision 2, 3, 4, 5
• Treatment options include:
  • Weight loss 2, 3, 4, 5, 6
  • Acetazolamide 2, 3, 4, 5, 6
  • Drainage of cerebrospinal fluid 2
  • Optic nerve sheath fenestration 2, 3, 4, 5
  • Stent angioplasty of a sinus stenosis 2
  • Lumboperitoneal shunting 5
  • Bariatric surgery for severely obese patients 5