You smile as you dispatch the resident to check out a 17-year-old girl with a chief complaint of migraine headache. Migraines can be so satisfying to treat. You give them a liter of fluid with some IV pain meds, turn out the lights and they usually feel much better when you check on them later. Anticipating this plan, you go about your other business until the resident comes out with the story. Yeah, you should have known it wasn’t going to be this straight forward.
The patient has already been seen several times for headaches in your institution. She was diagnosed with pseudotumor cerebri, or idiopathic intracranial hypertension (IIH) by neurology a few weeks ago. She originally came in complaining of throbbing headache and intermittent vision loss. As part of the work-up she had a lumbar puncture that demonstrated increased opening pressure. Some CSF was taken off and the closing pressure was normalized. The patient felt better and was sent home with diamox, which she was semi-compliant about taking. After three weeks her symptoms returned and she again had a lumbar puncture, again with improvement of her headache. That was five days ago. She’s been on her diamox the past five days, but her headache returned yesterday. She tried several medications she has used in the past for migraine headaches, but they are not helping. She again reports intermittent vision loss. In addition, she reports low back pain since the last spinal tap. She says these symptoms are the same as they were the last two times she came in. She wants to know if you are going to do another spinal tap.
You proceed to her examination. She is a very overweight teen with unremarkable vitals. Her fundoscopic exam does not show papilledema tonight; she says it didn’t last time either. Her pupils are equal, round and reactive, her extra-ocular movements are intact. Her visual acuity is 20/25 bilaterally and her visual fields seem OK. The rest of her examination, including a thorough neurological exam, is also normal.
The resident wants to know if he should get an LP tray out. She just got tapped five days ago. How fast does CSF re-accumulate? Are serial LPs a reasonable treatment for her headaches?
The first question is easy enough to answer. People are pretty efficient when it comes to CSF production. The fluid they took off during her last LP would have re-accumulated within a few hours. So should you just keep taking it off? She’s still sore from the last LP.
IIH, or pseudotumor cerebri presents with signs and symptoms consistent with increased intracranial pressure (headache, vision loss, papilledema). It is diagnosed after other causes of increased intracranial pressure have been ruled out. Patients with IIH will have disabling headaches and they can go on to have permanent vision loss. A diagnostic lumbar puncture will have normal CSF but an elevated opening pressure. Patients will get some relief from the removal of enough CSF to get the closing pressure down into the normal range.
However, serial spinal taps for fluid drainage are not generally recommended for the treatment of IIH, except as a prelude to surgery in a patient with severe, progressive vision loss or intractable headache who has either failed optimal medical management or cannot be treated with medication. Spinal taps hurt, they can produce complications, and they can be hard to do since many patients with IIH are obese.
Medication is more promising. Carbonic anhydrase inhibitors purportedly reduce the rate that CSF is made. Acetazolamide (diamox) is the usual one prescribed. Loop diauretics, such as furosimide (lasix) can be added to acetazolamide for additional benefit. Routine migraine medications can also be helpful although rebound headaches from the overuse of analgesics are a common problem. Steroids are controversial.
This patient was sent home and told to continue her diamox, start lasix, take her migraine meds for headache, and see the neurologist in a few days.
Handling the ED patient who comes in with IIH
~ Perform an eye exam. If the patient has severe progressive vision loss, it is an emergency. Otherwise, you can treat conservatively.
~ Optimize medical management. Make sure the patient is on an appropriate dose of acetazolamide (diamox). Consider adding furosimide (lasix). Consider additional, conventional headache therapy.
~ Ensure good follow-up.
~ No spinal tap is necessary unless the patient has severe progressive vision loss.
Amy Levine, MD, is an associate professor of pediatric emergency medicine at UNC Chapel Hill