Idiopathic intracranial hypertension (IIH) is a severe neurological disorder that has been linked to hormonal birth control products. This condition, which often presents like a large brain tumor, is caused by sudden increased pressure inside the skull. Symptoms of idiopathic intracranial hypertension include headache, vision problems, ringing of the ears (tinnitus), and papilledema (swelling of the optic nerve).
What is Implanon?
Implanon is a flexible plastic implant that is inserted under the skin of a woman’s upper arm. The implant is designed to prevent pregnancy for up to three years. Implanon is made by Merck, and was approved by the FDA in 2006.
What is Idiopathic Intracranial Hypertension?
IIH is characterized by increased pressure inside the brain (intracranial pressure) that causes symptoms that tend to mimic a brain tumor. The condition occurs when cerebrospinal fluid (CSF) builds up in the brain, and may be caused by an increase in fluid production or decrease in fluid absorption. Idiopathic intracranial hypertension has also been referred to in the medical literature as pseudotumor cerebri (PTC) and benign intracranial hypertension (BIH).
Hormonal Birth Control and IIH
It is still not clearly understood why IIH occurs in many patients. However, certain medications including hormone-based birth control products have been associated with the condition. One hormone in particular, levonorgestrel, was linked to idiopathic intracranial hypertension in 1995.
Symptoms of idiopathic intracranial hypertension include:
- Changes in vision
- Vision loss
- Papilledema (swelling of the optic nerve)
- Feeling dizzy or nauseated
- Neck stiffness
- Difficulty walking
- Persistent ringing in the ears (tinnitus)
The following diagnostic tests may be performed to confirm a diagnosis of IIH and rule out a brain tumor:
- MRI or CT scans of the brain
- Spinal tap (lumbar puncture)
- Eye exam