Headache attributed to idiopathic intracranial hypertension (IIH) (pseudotumor cerebri) is a secondary headache disorder. Secondary headache disorders are those that are cause by or related to another condition. In this case, the headache is secondary to IIH.
Headache attributed to IIH is often daily. It is most often a steady ache, not pulsatile, and is worsened by coughing or straining. This type of headache develops in relation to increased intracranial pressure. It improves when cerebrospinal fluid is drawn off to reduce the pressure to normal range during a lumbar puncture (spinal tap), and it stops within 72 hours of maintaining normal intracranial pressure.
Idiopathic intracranial hypertension is said to be a rare disorder, but some experts think it possible that it's not as rare as it's thought to be; it's just not being diagnosed. Part of the problem is that neither patients nor many doctors fully understand IIH or how it's diagnosed. It is too often dismissed as a possibility when patients don't have papilledema, but it's a misconception that papilledema must be present with IIH. There are two methods for accurately diagnosing IIH:
- lumbar puncture (spinal tap)
- intraventricular pressure monitoring (CSF pressure monitoring)
Intraventricular pressure monitoring is the more difficult method. You can read more about it HERE.
For those of you who like more detail, below is the diagnostic and classification criteria for headache attributed to idiopathic intracranial hypertension, as set forth in he International Headache Society. The International Classification of Headache Disorders, 2nd Edition (ICHD-II), 1st revision:
7.1.1 Headache attributed to idiopathic intracranial hypertension (IIH)1
A. Progressive headache with at least one of the following characteristics and fulfilling criteria C and D:
1. daily occurrence
2. diffuse and/or constant (non-pulsating) pain
3. aggravated by coughing or straining
B. Intracranial hypertension fulfilling the following criteria:
1. alert patient with neurological examination that either is normal or demonstrates any of the following abnormalities:
b) enlarged blind spot
c) visual field defect (progressive if untreated)
d) sixth nerve palsy
2. increased CSF pressure (more than 200 mm H2O in the non-obese, more than 250 mm H2O in the obese) measured by lumbar puncture in the recumbent position or by epidural or intraventricular pressure monitoring (CSF pressure monitoring)
3. normal CSF chemistry (low CSF protein is acceptable) and cellularity
4. intracranial diseases (including venous sinus thrombosis) ruled out by appropriate investigations
5. no metabolic, toxic or hormonal cause of intracranial hypertension
C. Headache develops in close temporal relation to increased intracranial pressure
D. Headache improves after withdrawal of CSF to reduce pressure to 120-170 mm H2O and resolves within 72 hours of persistent normalisation of intracranial pressure
IIH most commonly occurs in young obese women.
Although the majority of patients with IIH have papilloedema, IIH without papilloedema is observed. Other symptoms or signs of IIH include intracranial noises, tinnitus, transient visual obscurations and diplopia.