Published: 3 March 2016

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Idiopathic Intracranial Hypertension

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Prescriber Update 37(1): 7
March 2016

Idiopathic intracranial hypertension (IIH, previously known as pseudotumor cerebri) is a disorder of increased cerebrospinal fluid pressure in which patients maintain an alert and oriented mental state. Signs and symptoms include headache, pulsatile tinnitus, diplopia, papilloedema and visual loss^1,2.

IIH occurs more often in women than men and most commonly occurs in obese women of childbearing age. More than 90% of patients with IIH are obese and the incidence is rising in parallel with the increasing prevalence of obesity².

Other risk factors for IIH include hyperaldosteronism, Cushing’s syndrome, hypervitaminosis A, use of recombinant growth factor and some medicines.

Medicines known to be associated with IIH include^1-4:

• antibiotics including tetracyclines (eg, minocycline, doxycycline), naldixic acid and nitrofurantoin
• steroids (on withdrawal)
• contraceptives
• vitamin A derivatives such as isotretinoin
• indomethacin or ketoprofen in patients with Bartter’s syndrome
• amiodarone
• thyroid replacement therapy in hypothyroid children.

Because of the risk of IIH, concomitant use of tetracyclines and vitamin A or retinoids is contraindicated.

Prompt discontinuation of the causative medicine leads to resolution of the disorder, usually over two to four weeks³. Weight loss is associated with improvement of IIH in overweight patients⁴.

Of the reports of IIH received by the Centre for Adverse Reactions Monitoring (CARM), 84% occurred in females and 69% of reports in females were associated with a tetracycline or a contraceptive medicine.

Any suspected or confirmed case of IIH in association with medicines should be reported to CARM (https://nzphvc.otago.ac.nz/).

References

1. Ko MW, Liu GT. 2010. Pediatric Idiopathic Intracranial Hypertension (Pseudotumor Cerebri). Hormone Research in Paediatrics 74: 381-389.
2. Wall M. 2010. Idiopathic Intracranial Hypertension. Neurologic Clinics 28(3): 593-617.
3. Lochhead J, Elston JS. 2003. Doxycycline induced intracranial hypertension. BMJ 326: 641-642.
4. Andrews LE, Liu GT, Ko MW. 2014. Idiopathic Intracranial Hypertension and Obesity. Hormone Research in Paediatrics 81: 217-225.