Migraine Comorbidities - Idiopathic Intracranial Hypertension
Idiopathic intracranial hypertension (IIH) is sometimes comorbid with Migraine, which means that they can occur at the same time, but neither causes the other.
In the simplest of terms, IIH, sometimes called pseudotumor cerebri, is a condition in which the body either produces too much cerebrospinal fluid or doesn't absorb it well. This results in increased cerebrospinal fluid pressure.
In literal terms, pseudotumor cerebri means "false brain tumor." The name pseudotumor cerebri has been used for this condition because its symptoms mimic those of brain tumors.
It is officially and more accurately called Idiopathic Intracranial Hypertension (IIH). It's termed "idiopathic" because it's cause is not truly known. It is likely due to high pressure caused by the buildup or poor absorption of cerebrospinal fluid in the subarachnoid space surrounding the brain, but the reasons for the buildup or poor absorption aren't known. The disorder is most common in women between the ages of 20 and 50. Being overweight seems to be a possible contributing factor, but IIH should not be ruled out based only on body weight, age, or gender.
Symptoms of IIH:
- headache, sometimes daily, sometimes severe, and not relieved by medication
- hearing loss
- impaired vision or eventual blindness
- memory issues
- Migraine attacks with unidentified triggers
- pain behind the eyes
- pulsating intracranial noises
- shoulder and/or neck pain
Diagnosis of IIH:
The only definitive diagnostic tests for IIH are lumbar puncture (LP) (spinal tap) or epidural or intraventricular pressure monitoring (CSF pressure monitoring). A lumbar puncture is the easier method, with the opening cerebrospinal fluid (CSF) pressure measured when the needle is inserted.
In some patients, swelling of the optic nerve (papilledema) can be observed in a thorough eye exam. However, it is important to note that the absence of papilledema does not rule out IIH. Not all patients with IIH exhibit papilledema. When the LP is performed, it is also essential that the protein level and cell count of the fluid be tested. The presence of protein or elevated white blood cell count indicate can indicate that inflammation or infection could be causing the elevated CSF pressure. The second, more complicated method of diagnosing IIH is intraventricular pressure monitoring (CSF pressure monitoring).
Secondary Intracranial Hypertension:
While IIH is idiopathic in origin, secondary intracranial hypertension always has a cause. Diagnosis of secondary IH is the same as IIH, but secondary IH can be traced back to causes such as other conditions or medications:
- dural venous sinus thrombosis
- kidney failure
- excess Vitamin A
- growth hormone treatments
- nasal fluticasone propionate (Flonase)
- Medications, commonly medications with diuretic actions. (Diamox is a common choice.)
- Discontinuing medications that can exacerbate the condition. (Includes oral contraceptives and some steroids)
- Weight loss.
- When medications fail to control the CSF pressure, therapeutic shunting, which involves surgically inserting a draining tube from the spinal fluid space in the lower spine into the abdominal cavity, may be needed to remove excess fluid and relieve pressure.
With treatment and regular follow-up with physicians, the prognosis for most patients is excellent. Even if papilledema is not found, regular ophthalmologic exams are required to monitor any changes in vision or the onset of papilledema. In extreme cases, surgery may be needed to remove pressure on the optic nerve. The disorder may cause progressive, permanent visual loss in some patients.
IIH and Migraine:
Even though IIH and Migraine can't cause each other, IIH can impact Migraines. IIH can cause trigger Migraines. It can also keep Migraine preventives from working properly. If you and your doctor can't identify the triggers for your Migraines, or you're experiencing other symptoms of IIH, talk with your doctor about performing a lumbar puncture to check for IIH.
My personal experience with IIH and Migraine:
When I first sought treatment with a Migraine specialist, I was having Migraines five or six days a week. I was keeping a detailed Migraine diary, but could only identify my triggers about 50% of the time, and preventive medications weren't working. My doctor suggested doing a spinal tap to check for IIH. The opening pressure was above the "normal" range, but he didn't want to diagnose IIH immediately because there was no way to know if that was really too high for me. While doing the LP, he drew off enough cerebrospinal fluid to put my pressure into normal range. Then he had me go home, continue my diary, and return to see him in three weeks. (It would take far longer than that for the fluid he withdrew to replenish.) During that three-week period, I only had half as many Migraines and was able to identify triggers for all of them. That demonstrated that the opening pressure had been too high for me and I did have IIH. After we consulted with my ophthalmologist (because I have glaucoma), we chose Diamox for treating the IIH. After that, we were able to find an effective preventive regimen for me.
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