Fourth nerve palsy in pseudotumor cerebri

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.

Hemifacial Spasm as a Rare Clinical Presentation of Idiopathic Intracranial Hypertension: Case Report and Literature Review

OBJECTIVES

To report a rare case of idiopathic intracranial hypertension (IIH) presenting with hemifacial spasm (HFS) and review the current literature.

METHODS

Case report and literature review. The patient's medical record was reviewed for demographic and clinical data. For literature review, all case reports or other publications published in English literature were identified using PUBMED.

RESULTS

A 43-year-old obese female presented with a 2-year history of left HFS.Electroencephalography and head computed tomography were unremarkable. Magnetic resonance imaging demonstrated bilateral anterior inferior cerebellar artery vascular loops involving the internal auditory canals as well as IIH-associated findings. A lumbar puncture was performed and revealed an elevated opening pressure of 26 cm H₂0 cerebrospinal fluid. Acetazolamide treatment was then initiated, resulting in complete resolution of the HFS.

CONCLUSION

HFS may be a rare presenting manifestation of IIH, and treatment of IIH may result in improvement of HFS symptoms. This is the first report of IIH presenting with HFS in the absence of headache or visual change. As a result, this is the first report of HFS as a presenting manifestation of IIH in Otolaryngology literature.

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.

Stroke mimics

Stroke mimics are an important consideration for emergency physicians and physician extenders working in emergency departments. The emergency medicine physician must determine whether the acute neurologic deficits represent a transient event or a potential stroke. This article describes the common stroke mimic presentations by cause, including toxic-metabolic pathologies, seizure disorders, degenerative neurologic conditions, and peripheral neuropathies.

Fourth cranial nerve palsy in pediatric patients with pseudotumor cerebri

PURPOSE

To describe three children with acute fourth cranial nerve palsy secondary to pseudotumor cerebri.

METHODS

We reviewed the medical records of children younger than 18 years who were diagnosed with pseudotumor cerebri between 1977 and 1997. Pseudotumor cerebri was defined by normal neuro-imaging, elevated intracranial pressure measured by lumbar puncture, and normal cerebrospinal fluid composition.

RESULTS

Three children with pseudotumor cerebri presented with vertical diplopia and clinical signs of fourth cranial nerve palsy including a hypertropia of the affected eye, which increased with adduction and ipsilateral head tilt. The fourth cranial nerve palsy resolved after reduction of the intracranial pressure in all three children.

CONCLUSIONS

Fourth cranial nerve palsy may occur in children with pseudotumor cerebri and may be a nonspecific sign of elevated intracranial pressure.

Pseudotumor cerebri in children

PURPOSE

Demographic and outcome data in the era of modern neuroimaging are needed to describe pseudotumor cerebri in children.

METHODS

We reviewed the medical records of children less than 18 years old who were diagnosed with pseudotumor cerebri between 1977 and 1997. We defined pseudotumor cerebri as (1) increased intracranial pressure, (2) normal or small ventricles, and (3) normal cerebrospinal fluid composition. The condition might be idiopathic or the result of a nontumor etiology.

RESULTS

Thirty-seven patients had an initial diagnosis of pseudotumor cerebri. Two patients were subsequently diagnosed with a central nervous system malignancy and were excluded from further analysis. The remaining 35 patients included 10 patients with idiopathic pseudotumor cerebri and 25 patients with disorders reported to be associated with pseudotumor cerebri. The mean age was 10.6 years with a range of 3 to 17 years. Twenty patients (57%) were female and 13 patients (37%) were obese. At presentation 4 patients had a visual acuity less than 20/40 in the best eye and 10 patients had visual field deficits. Seventeen patients (49%) had cranial nerve deficits, all of which resolved with normalization of the intracranial pressure. Follow-up data were obtained on 30 patients. Only one patient had a final visual acuity less than 20/40 in the best eye, whereas six patients had residual visual field deficits. Ten patients (33%) had optic nerve atrophy.

CONCLUSIONS

There was no gender predominance, and associated etiologic factors were common in these children with pseudotumor cerebri. Permanent visual loss occurs in some children with pseudotumor cerebri. Quantitative perimetry and optic nerve examination were more sensitive than visual acuity determination in detecting damage to the visual sensory system. In rare instances the patient diagnosed with pseudotumor cerebri will be found after extended follow-up to harbor an intracranial neoplasm.