Hearing loss as a false localising sign in raised intracranial pressure

Evaluation of peripheral and central olfactory regions by MRI in patients with idiopathic intracranial hypertension

OBJECTIVES

We investigated the peripheral and central smell regions in patients with idiopathic intracranial hypertension (IIH) by cranial MRI.

METHODS

In this retrospective study, cranial MRI images of 43 adult patients with IIH (Group 1) and 43 healthy adults without IIH (Group 2) were included. In both groups, peripheral [Olfactory bulb (OB) volume and Olfactory sulcus (OS) depth] and central smell regions (insular gyrus and corpus amygdala area, and thalamus volume) were measured in cranial MRI.

RESULTS

Bilateral OB volume and insular gyrus area, and right corpus amygdala and thalamus volumes of the IIH group were significantly lower than those of the control group (p < 0.05). In the IIH group, OB volume of the right side was significantly lower, and insular gyrus area of the right side was significantly higher than those of the left side (p < 0.05). In the IIH group, there were positive correlations between OB volumes; OS depths; insular gyrus areas; corpus amygdala areas; and thalamus volumes bilaterally (p < 0.05). In older patients, right OS depth and right corpus amygdala area decreased (p < 0.05).

CONCLUSION

In conclusion, IIH may be related to olfactory impairment. Cranial MRI images showed a decrease in peripheral (OB volume) and central (insular gyrus and corpus amygdala area and thalamus volume) smell regions. To prevent olfactory impairment in IIH patients, treatment should be done in IIH patients to decrease intracranial pressure. It is very important to prevent the circulation of CSF with increased pressure between the sheets of the olfactory nerve in IIH patients.

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.

Pediatric Idiopathic Intracranial Hypertension Presenting With Sensorineural Hearing Loss

OBJECTIVE

To present the rare case of a young boy with idiopathic intracranial hypertension presenting with bilateral sensorineural hearing loss developing over several months. This was accompanied by headaches, otalgia, tinnitus, and vertigo. Furthermore, we aim to provide a concise review on this matter, as this report represents the second case in literature of pediatric idiopathic intracranial hypertension presenting with hearing loss.

METHODS

Workup of a 9-year-old boy with bilateral sensorineural hearing loss, including (among others) physical examination, audiometry, diagnostic imaging, and lumbar puncture.

RESULTS

Physical examination including fundoscopy as well as imaging showed no abnormalities. At presentation, pure tone audiometry revealed bone conduction thresholds of about 30 dB HL in both ears. Two months later, this declined to about 35 dB HL in both ears. Lumbar puncture revealed an increased intracranial pressure. The boy was thus diagnosed with idiopathic intracranial hypertension. After the lumbar puncture, the otological complaints gradually resolved, and the hearing normalized (bone conduction thresholds of 0-5 dB HL).

CONCLUSION

Although rare, sensorineural hearing loss in the pediatric population together with otalgia, tinnitus, and vertigo can be due to idiopathic intracranial hypertension and as such can be reversible.

An update on idiopathic intracranial hypertension

Idiopathic intracranial hypertension (IIH) is a condition of unknown etiology often encountered in neurologic practice. It produces nonlocalizing symptoms and signs of raised intracranial pressure and, when left untreated, can result in severe irreversible visual loss. It most commonly occurs in obese women of childbearing age, but it can also occur in children, men, nonobese adults, and older adults. Although it is frequently associated with obesity, it can be associated with other conditions, such as obstructive sleep apnea and transverse cerebral venous sinus stenoses. Recent identification of subgroups at high risk for irreversible visual loss, including black patients, men, and patients with fulminant forms of IIH, help guide the optimal management and follow-up. Ongoing studies of venous anatomy and physiology in IIH patients, as well as a recently begun randomized clinical treatment trial, should provide further insight into this common yet poorly understood syndrome.

More than meets the eye? Redefining idiopathic intracranial hypertension

Idiopathic intracranial hypertension (IIH) is a disease of unknown etiology associated with increased intracranial pressure, predominantly affecting obese females of childbearing age. The history of IIH is quite unique, featuring only limited advancements in evidenced-based treatments, but boasting literally countless changes in nomenclature, proposed etiology, and conceptual approach. Despite its elusive pathogenesis, an evolution of our approach to IIH can be traced sequentially through identifiable periods. Contemporary research suggests that we are approaching a new phase in IIH, redefining it as a global neurologic syndrome with more far-reaching effects than previously realized.

Pseudotumor cerebri

Pseudotumor cerebri is a perplexing syndrome of increased intra-cranial pressure without a space-occupying lesion. The terminology for the disorder has changed over the years and the diagnostic criteria revised to reflect advances in diagnostic technology and insights into the disease process. The classification and nomenclature depend on the presence or absence of an underlying cause. When the diagnostic criteria are followed, a secondary etiology is unlikely. When no secondary cause is identified, the syndrome is termed "idiopathic intracranial hypertension."

False localising signs

Neurological signs have been described as "false localising" if they reflect dysfunction distant or remote from the expected anatomical locus of pathology, hence challenging the traditional clinicoanatomical correlation paradigm on which neurological examination is based. False localising signs occur in two major contexts: as a consequence of raised intracranial pressure, and with spinal cord lesions. Cranial nerve palsies (especially sixth nerve palsy), hemiparesis, sensory features (such as truncal sensory levels), and muscle atrophy, may all occur as false localising signs. Awareness that signs may be false localising has implications for diagnostic investigation.