Combined VIth and VIIth nerve palsy: Consider idiopathic intracranial hypertension!

Imaging the brain: diagnosis aided by structural features on neuroimaging studies

The use of neuroimaging allows the ophthalmologist to identify structural lesions in the orbit or along the neuroaxis that allow for more accurate diagnosis and treatment of patients with neuro-ophthalmic diseases. The primary imaging tools include computed tomography (CT) and magnetic resonance imaging (MRI), both of which can be used to evaluate the brain, spinal cord and canal, and orbits. Neurovascular structures, both arterial and venous, also can be imaged in high resolution with modern CT and MR angiography and CT and MR venography. In many cases, invasive procedures such as catheter angiography can be avoided with these studies, and angiography is often reserved for confirmation of vascular lesions combined with endovascular treatment. In this article, we illustrate how the evaluation of patients presenting with neuro-ophthalmic diseases involving the afferent and efferent visual pathways can be optimized with the use of appropriate diagnostic imaging studies. The complementary value of ophthalmic imaging is also demonstrated, and the advantages and disadvantages of both CT and MRI as well as their use in longitudinal patient follow up is demonstrated.

Expanding the clinical spectrum of idiopathic intracranial hypertension

PURPOSE OF REVIEW

Idiopathic intracranial hypertension (IIH) is a disorder of raised intracranial pressure (ICP). Although the majority of patients with IIH present classically with headache and papilledema, some patients may have unusual presentations or manifestations. Recent advancements in neuroimaging have facilitated the identification of other presentations associated with IIH. This review provides an overview of the expanding clinical spectrum of IIH.

RECENT FINDINGS

Presentations of IIH that are considered unusual include highly asymmetric or unilateral papilledema, IIH without papilledema, and IIH associated with cranial nerve involvement. These presentations likely reflect differences in the way cerebrospinal fluid (CSF) pressure is transmitted intracranially. Radiological signs of intracranial hypertension are increasingly recognized in patients with IIH and provide further insights into the effects of raised ICP on intracranial structures. Osseous changes in the skull base leading to formation of meningoceles and encephaloceles have been identified in patients with IIH, spontaneous skull base CSF leak, and drug-resistant temporal lobe epilepsy, suggesting a possible association.

SUMMARY

Clinicians should be familiar with the expanding clinical spectrum of IIH and the implications for the management of these presentations.

Atypical presentations of idiopathic intracranial hypertension

Idiopathic intracranial hypertension (IIH) is a disorder of unknown etiology that results in isolated raised intracranial pressure. Classic symptoms and signs of IIH include headache, papilledema, diplopia from sixth nerve palsy and divergence insufficiency, and pulsatile tinnitus. Atypical presentations include: (1) highly asymmetric or even unilateral papilledema, and IIH without papilledema; (2) ocular motor disturbances from third nerve palsy, fourth nerve palsy, internuclear ophthalmoplegia, diffuse ophthalmoplegia, and skew deviation; (3) olfactory dysfunction; (4) trigeminal nerve dysfunction; (5) facial nerve dysfunction; (6) hearing loss and vestibular dysfunction; (7) lower cranial nerve dysfunction including deviated uvula, torticollis, and tongue weakness; (8) spontaneous skull base cerebrospinal fluid leak; and (9) seizures. Although atypical findings should raise a red flag and prompt further investigation for an alternative etiology, clinicians should be familiar with these unusual presentations.

The effect of CSF drain on the optic nerve in idiopathic intracranial hypertension

Background

Elevation of intracranial pressure in idiopathic intracranial hypertension induces an edema of the prelaminar section of the optic nerve (papilledema). Beside the commonly observed optic nerve sheath distention, information on a potential pathology of the retrolaminar section of the optic nerve and the short-term effect of normalization of intracranial pressure on these abnormalities remains scarce.

Methods

In this exploratory study 8 patients diagnosed with idiopathic intracranial hypertension underwent a MRI scan (T2 mapping) as well as a diffusion tensor imaging analysis (fractional anisotropy and mean diffusivity). In addition, the clinical presentation of headache and its accompanying symptoms were assessed. Intracranial pressure was then normalized by lumbar puncture and the initial parameters (MRI and clinical features) were re-assessed within 26 h.

Results

After normalization of CSF pressure, the morphometric MRI scans of the optic nerve and optic nerve sheath remained unchanged. In the diffusion tensor imaging, the fractional anisotropy value was reduced suggesting a tissue decompression of the optic nerve after lumbar puncture. In line with these finding, headache and most of the accompanying symptoms also improved or remitted within that short time frame.

Conclusion

The findings support the hypothesis that the elevation of intracranial pressure induces a microstructural compression of the optic nerve impairing axoplasmic flow and thereby causing the prelaminar papilledema. The microstructural compression of the optic nerve as well as the clinical symptoms improve within hours of normalization of intracranial pressure.

Idiopathic intracranial hypertension presenting with isolated unilateral facial nerve palsy: a case report

BACKGROUND

Idiopathic intracranial hypertension, also known as pseudotumor cerebri, is a disorder characterized by increased intracranial pressure of unclear pathogenesis in the absence of other structural and obstructive lesions that is predominantly, although not exclusively, seen in obese women of childbearing age. Patients with idiopathic intracranial hypertension commonly present with a headache, transient visual obscurations, and intracranial noises with some cranial nerves occasionally involved, most commonly CN VI. We report idiopathic intracranial hypertension presenting with isolated complete unilateral facial nerve palsy, as the sole cranial nerve involved, which is a presentation rarely reported in the literature.

CASE PRESENTATION

A 40-year-old Hispanic woman with a history of obesity and hypertension presented to our emergency department complaining of bifrontal headache for 3 days associated with nausea, vomiting, transient visual disturbances, and a picture of right-sided cranial nerve VII palsy. Her neurologic examination including other cranial nerves was otherwise normal, but a fundus examination revealed bilateral grade II papilledema. Imaging studies ruled out structural and obstructive lesions as possible causes of her symptoms and lumber puncture results were unremarkable except for an increased opening pressure. She was then started on prednisone and acetazolamide. Two days later, she reported a dramatic improvement in both headache and facial nerve palsy.

CONCLUSIONS

Idiopathic intracranial hypertension should be suspected in obese young women presenting with headache and transient visual complaints and some cranial nerve abnormalities. Idiopathic intracranial hypertension is a diagnosis of exclusion and imaging studies should always be performed to rule out other structural and obstructive lesions. In this case report, we aimed to draw attention to the possibility of idiopathic intracranial hypertension presenting with unilateral cranial nerve VII palsy as the only cranial nerve involved, which needs a high index of suspicion by clinicians. The mechanisms of cranial nerve VII palsy in idiopathic intracranial hypertension are not well understood and prompt further investigation.

Idiopathic intracranial hypertension: Proposal of a stratification strategy for monitoring risk of disease progression

OBJECTIVES

A general consensus based on a multidisciplinary perspective involving an international panel was recently developed for management of patients with idiopathic intracranial hypertension (IIH). In this paper, the authors sought to develop further on the aspect of this consensus that concerns monitoring progression of the disease.

PATIENTS AND METHODS

A systematic literature review of previous publications on monitoring disease progression in IIH and a meta-analysis to examine efficacy of method of monitoring employed in each study. The authors present a brief descriptive analysis of challenges with monitoring progression of the disease and propose a risk stratification to aid monitoring.

RESULTS

Of a total of 382 publications identified from the literature search, only 8 studies (144 patients) satisfied inclusion criteria and were included for analysis. Among these, 3 were based on ICP monitoring while the remaining 5 focused on ophthamological evaluation. Interestingly, there were neither any studies on monitoring with progression of clinical features nor any study on monitoring with symptomatology associated with IIH among the selected studies.

CONCLUSION

There is a paucity of studies in the literature on methods of monitoring disease progression in IIH. Though close attention to adequate evaluation and proper care of patients with IIH remains the key in managing this problem, this proposed risk stratification will be an objective tool and useful guide to better monitor these patients according to their extent of risk from the disease and possibly for planning treatment and intervention.