Abstract
Idiopathic intracranial hypertension (IIH) is an infrequent disease of unknown aetiology. A clinical presentation of chronic headache and papilloedema in an obese woman of childbearing age and normal neuroimaging prompts a strong clinical suspicion, although several other symptoms and signs such as transient visual obscurations (TVO), diplopia, tinnitus nausea and vomiting can be common. As many as 25% of IIH patients develop permanent visual loss. The diagnosis requires the exclusion of several systemic, endocrinological and iatrogenic conditions known to increase intracranial pressure, and the demonstration of a hypertensive cerebrospinal fluid (CSF) by lumbar puncture (LP) (1).
There is evidence that IIH can occur without papilloedema and papilloedema-related visual symptoms. In such cases, IIH appears clinically indistinguishable from chronic daily headache, a condition with a 4–5% prevalence in the general population (2).
We recently observed two cases of IIH presenting with papilloedema, in which headache was completely absent or remitted during pregnancy.
A 28-year-old obese nullipara, with an unremarkable past clinical history, underwent ophthalmoscopy for the subacute appearance of almost daily TVO episodes mainly in the supine position. The examination revealed a bilateral papilloedema, confirmed by the echographic finding of a bilateral enlargement of the optic nerve diameter (right 5.62 mm; left 5.11 mm). The patient did not complain of headache; moreover, she reported ‘I never had a headache in my life’. All her first-degree relatives shared the trait. The neurological examination and brain magnetic resonance imaging (MRI) were normal. Haematological investigations excluded endocrinological, autoimmune and thrombotic disorders. LP revealed a clinostatic opening pressure of 360 mmH2O. This value fell to 160 mmH2O after subtraction of 20 cm3 of CSF. Soon after LP, TVO episodes disappeared. Despite the lack of headache the patient was diagnosed with IIH and acetazolamide 250 mg b.i.d. was started. At a 2-month follow-up the patient was still asymptomatic and both the papilloedema and optic nerve diameter had normalized. Acetazolamide was therefore discontinued. A new 4-month follow-up confirmed the absence of visual symptoms, papilloedema and optic nerve enlargement.
A young woman suffering of a menstrual-related migraine without aura since the age of 14 years received a diagnosis of IIH at the age of 22 years for the appearance of a mainly clinostatic daily headache, tinnitus, bilateral papilloedema and TVO. The diagnosis was confirmed after a negative brain MRI and after the demonstration of a hypertensive CSF by LP. The patient was treated for 3 months with acetazolamide 250 mg b.i.d., reporting the complete remission of intracranial hypertensive symptoms and signs. After 2 years a daily occipital headache recurred, worsened by lying down. Other symptoms included tinnitus, diplopia and TVO. Subjective symptomatology fluctuated in the next 2 months and suddenly worsened at the beginning of a pregnancy. We first observed the patient at the end of the 8th week of pregnancy. The neurological examination was unremarkable; ophthalmoscopy revealed bilateral papilloedema, confirmed by the echographic finding of optic nerve enlargement (right 5.7 mm; left 5.11 mm). Perimetry revealed bilateral increase of blind spot size. The patient reported that both migraine attacks and clinostatic headache, but neither papilloedema nor TVO, had progressively improved to disappear completely within the 6th week of pregnancy. We refrained from treating the patient because of negative neuroimaging and recommended monthly optic nerve echography, perimetry and clinical follow-up. While papilloedema and optic nerve enlargement persisted with mild fluctuations in the remaining pregnancy period, no clinostatic headache or migraine attacks were reported at follow-up visits. The patient delivered a healthy child by caesarean section on general anaesthesia. Soon after lactation ceased, about 4 weeks after delivery, migraine attacks and a clinostatic diffuse headache reappeared. LP revealed an opening CSF pressure of 280 mmH2O that fell to 140 mmH2O after CSF (20 cm3) subtraction. Thus an IIH diagnosis was confirmed and acetazolamide 250 mg b.i.d. was started. Soon after LP the patient reported the disappearance of both clinostatic headache and TVO. After 2 months she was symptom free (apart from one or two migraine attacks per month, mainly during menstruation) and investigations demonstrated the absence of papilloedema and the normalization of the optic nerve diameter. Acetazolamide was then discontinued. A second follow-up visit, 4 months after LP, confirmed the complete remission of symptoms and signs of intracranial hypertension.
The lack of headache in the former patient may reflect an inherited condition of protection against neurovascular headache development, since neither the patient nor her first-degree relatives reported headache in their lives. Similarly, in the latter patient the IIH-related headache remitted during pregnancy, which is considered a strong migraine protective factor. Our observations are in agreement with the hypothesis of a pathogenic link between migraine and IIH-related headache (3, 4). The existence of IIH without headache has not been addressed by previous reports; in a retrospective investigation among 240 pregnant women (5), 12 IIH cases were identified (5%). Two (16.6%) were headache free but this finding was not discussed further. Many IIH patients with papilloedema do not complain of visual symptoms but of an almost continuous refractory headache that finally leads to the diagnosis. Conversely, IIH cases occurring with an asymptomatic papilloedema and without headache could remain long undiagnosed. Such observations suggest that the prevalence of IIH without headache in the general population may be underestimated.