Idiopathic Intracranial Hypertension (IIH), also known as Pseudotumor Cerebri (PTC), is a neurological disorder characterized by abnormally high pressure of the cerebrospinal fluid (CSF) surrounding the brain. This elevated pressure can cause severe symptoms and potentially lead to permanent vision loss. For individuals diagnosed with IIH while using the levonorgestrel-releasing Mirena intrauterine device (IUD), removing the device is often the first step to determine if the hormonal component is the underlying trigger.
What Is Idiopathic Intracranial Hypertension (IIH)?
Idiopathic Intracranial Hypertension is a condition where the pressure within the skull increases without an identifiable cause, such as a tumor or infection. The disorder results from a disruption in the balance of cerebrospinal fluid (CSF), which is constantly produced and reabsorbed to cushion the brain and spinal cord. When the body produces too much CSF or fails to reabsorb it efficiently, the excess fluid volume leads to increased pressure inside the skull.
The most common symptoms are intense, daily headaches, which often worsen with position changes, and a pulsing noise in the ears known as pulsatile tinnitus. Of greater concern is the effect on vision, as the pressure can cause the optic nerve to swell, a condition called papilledema. This swelling can lead to brief episodes of vision dimming, loss of peripheral vision, or even permanent blindness if the pressure is not controlled.
The association between IIH and the Mirena IUD, which releases the synthetic progestin levonorgestrel, is based primarily on case reports and observational data. Studies analyzing adverse event reports have shown a higher than expected number of IIH cases linked to the device. Although the IUD is designed to deliver the hormone locally, systemic absorption of levonorgestrel does occur, leading researchers to hypothesize a hormonal influence on CSF dynamics. This possibility is often sufficient for clinicians to warrant removal of the device upon diagnosis.
Outcomes Following Mirena Removal
For patients diagnosed with IIH where the IUD is considered a potential trigger, removal of the device is often the first therapeutic action. If the IIH is truly linked to levonorgestrel, removal eliminates the hormonal source, offering the possibility of symptom resolution. Observed data suggests that for some patients, symptoms, particularly headaches and visual disturbances, may begin to improve within weeks to months following the IUD extraction.
The success of Mirena removal as a sole treatment is highly variable and depends on individual factors, including the severity and duration of the IIH symptoms before removal. Patients who experienced a rapid onset of symptoms shortly after IUD insertion may have a better chance of full resolution compared to those who have had long-standing, severe IIH. Complete symptom resolution is not guaranteed, and in many cases, patients still require medical management to fully control their intracranial pressure.
Close monitoring by specialists, such as a neurologist and an ophthalmologist, is required following IUD removal. Monitoring involves repeat visual field testing and ophthalmoscopic examinations to assess for papilledema regression, which measures pressure control. If visual function does not stabilize or continues to decline, medical treatment must be initiated promptly to protect the optic nerve from irreversible damage. A follow-up lumbar puncture may also be performed to confirm if the intracranial pressure has normalized.
Medical Management of Persistent IIH
When IIH symptoms persist or do not completely resolve after the Mirena IUD is removed, the condition is treated as standard IIH, regardless of the initial suspected trigger. The medical approach focuses on reducing intracranial pressure to protect vision and alleviate headache frequency and severity. Physicians often rule out other secondary causes of IIH, such as certain medications, kidney disease, or underlying venous sinus issues, before initiating long-term therapy.
The primary pharmaceutical treatment is a diuretic class of medication called carbonic anhydrase inhibitors, such as acetazolamide. This drug works by directly decreasing the rate of cerebrospinal fluid production, thereby reducing the volume and pressure inside the skull. If maximum doses of acetazolamide are not tolerated or fail to control the symptoms, another drug like topiramate may be used, which can also help with weight loss, a known factor in IIH.
Surgical Options
For severe cases where vision loss is progressive despite maximal pharmaceutical intervention, surgical options are considered to relieve pressure. An optic nerve sheath fenestration (ONSF) involves cutting a small window into the sheath covering the optic nerve to allow CSF to drain and relieve pressure. Alternatively, a shunt procedure, such as a lumboperitoneal shunt, may be performed to divert excess CSF from the spinal canal to the abdominal cavity for reabsorption.
Weight management is a fundamental component of long-term IIH control for patients who are overweight, irrespective of whether the IUD was the initial trigger. Studies show that a modest weight reduction of 5 to 15 percent can significantly reduce intracranial pressure and improve symptoms. In cases of significant obesity, bariatric surgery has demonstrated effectiveness in achieving sustained remission of IIH.