Idiopathic Intracranial Hypertension: Implications for the Otolaryngologist

Clinical Predictors of Pulsatile Tinnitus in Patients With Idiopathic Intracranial Hypertension: An Age-Matched Cohort Study

INTRODUCTION

Pulsatile tinnitus (PT) occurs in many but not all patients with idiopathic intracranial hypertension (IIH). It is poorly understood why some patients with IIH develop PT, yet others do not. The purpose of this study was to determine if any clinical findings differ between those with and without PT in IIH, potentially shedding light on a pathophysiologic mechanism.

METHODS

Age-matched cohort analysis of patients with documented IIH and presence or absence of PT was performed, collecting data including body mass index (BMI), blood pressure, visual acuity, cerebrospinal fluid (CSF) opening pressure, sleep apnea, migraines, and transient visual obscurations, among others. Independent-sample t test and χ2 test were used to analyze continuous and binary variables, respectively, with multivariate analysis conducted including variables statistically significant on univariate analysis.

RESULTS

Eighty subjects with IIH met the inclusion criteria (40 PT+, 40 PT-). CSF opening pressure showed no significant difference between the two groups. The PT+ cohort was found to have an average BMI of 45.1 kg/m 2 , which was significantly higher than the PT- group (37.7 kg/m 2 ; p = 0.0023). PT+ pulse pressure (60.1 mm Hg) was also significantly higher than the PT- group (51.6 mm Hg; p = 0.019). PT+ patients were also significantly more likely to have sleep apnea ( p < 0.001) and migraines ( p = 0.0036). Multiple logistic regression revealed an adjusted odds ratio of 13.9 for sleep apnea, 4.1 for migraines, and 1.01 for every increase in unit of BMI.

CONCLUSION

Among patients with IIH, presence of PT is associated with higher BMI and pulse pressure, and increased incidence of sleep apnea and migraines. Given no significant difference in CSF pressures between the two groups, PT may not be a product of increased disease severity but may be related to sequelae of obesity, such as increased pulse pressure and sleep apnea.

Doxycycline-Induced Intracranial Hypertension Presenting as Unilateral Pulsatile Tinnitus

Background

Pulsatile tinnitus (PT) is increasingly recognized as a cardinal symptom of idiopathic intracranial hypertension (IIH). However, clinicians should remain aware of other causes of nonidiopathic or secondary intracranial hypertension manifesting as PT. We present 2 patients with isolated PT (without accompanying headache, blurred vision, and papilledema) thought to be secondary to tetracycline-induced intracranial hypertension. To our knowledge, these are the first cases of PT as the presenting symptom of this condition.

Cases

A 41-year-old female (body mass index [BMI] 29 kg/m2) with ocular rosacea was initially treated with minocycline. Shortly after transitioning to oral doxycycline and erythromycin eye ointment, she noted left-sided PT. Her PT resolved after discontinuing doxycycline. In a second case, a 39-year-old female (BMI 19 kg/m2) with acne presented with a three-year history of left-sided PT while on long-term oral doxycycline for many years. She denied visual or auditory changes and atypical headaches. MRI findings were concerning for intracranial hypertension. Three months later, the patient was seen by neuro-ophthalmology, with findings suggesting prior papilledema. The patient reported PT improvement after discontinuing doxycycline.

Conclusions

This case series highlights 2 cases of isolated PT as the sole symptom of intracranial hypertension that resolved with tetracycline cessation. The presentation and unexpected improvement following tetracycline discontinuation are atypical compared with previous reports of tetracycline-induced intracranial hypertension. Clinicians should maintain a high index of suspicion for all types of intracranial hypertension (idiopathic and secondary), even in patients with a lower BMI. Current and prior medications should be reviewed when considering the etiology of intracranial hypertension.

Combined surgical repair and venous sinus stenting for patients with skull base encephaloceles secondary to dural venous sinus stenosis

BACKGROUND

Chronically elevated intracranial pressure (ICP) seen in idiopathic intracranial hypertension (IIH) can cause the development of skull base encephaloceles and cerebrospinal fluid (CSF) leaks. Surgical repair and ventriculoperitoneal shunt (VPS) placement are mainstays of treatment. Venous sinus stenting (VSS) is a newly accepted treatment modality. The goal of this study was thus to determine if VSS can be used to treat symptoms and prevent recurrence after surgical encephalocele repair.

METHODS

Retrospective chart review of patients that had surgical repair of encephaloceles followed by VSS for symptomatic stenosis with elevated pressure gradient.

RESULTS

A total of 13 patients underwent a combined encephalocele repair and VSS. Seventy-two percent were female; 46% had headaches, 69% pulsatile tinnitus, and 92% CSF rhinorrhea or otorrhea. One had seizures. Mean lumbar opening pressure was 23.3 ± 2.6 cm H2O; the average sagittal-to-jugular pressure gradient was 12.7 ± 1.8 cmH2O and was elevated in all patients. Four patients had middle fossa craniotomy for repair of tegmen defect (one bilateral); one had a retrosigmoid craniotomy for repair of a sigmoid plate defect. Eight had an endoscopic endonasal repair for sphenoid or cribriform plate encephalocele. There were no VSS procedural complications or complications associated with dual antiplatelet therapy. One patient had meningitis after endoscopic repair that was treated with antibiotics. One patient had recurrence of both CSF leak and venous stenosis adjacent to the stent requiring repeat repair and VSS. There was no further recurrence.

CONCLUSION

In patients with dural sinus stenosis and encephaloceles requiring repair, VSS can be performed safely within weeks of surgery for relief of symptoms, resolution of underlying pathology, and prevention of CSF leak recurrence.

Radiographic Sigmoid Sinus Wall Abnormalities and Pulsatile Tinnitus: A Case-Control Study

OBJECTIVE

Compare incidence of sigmoid sinus wall abnormalities (SSWAs) and other radiographic abnormalities in patients with pulsatile tinnitus (PT) versus controls.

STUDY DESIGN

Retrospective case-control.

SETTING

Tertiary referral center.

PATIENTS

Adults with PT and high-resolution computed tomography imaging were compared with adults undergoing cochlear implant workup including high-resolution computed tomography imaging.

MAIN OUTCOME MEASURES

Incidence of SSWA in PT cohort (n = 141) compared with control (n = 149, n = 298 ears). Secondary outcome measures included differences in demographics and in other radiographic abnormalities between cohorts.

RESULTS

Patients with PT had a higher incidence of SSWA (34% versus 9%, p < 0.001) and superior canal dehiscence (23% versus 12%, p = 0.017) than controls. Spearman product component correlations demonstrated that ipsilateral PT was weakly associated with SSWA ( r = 0.354, p < 0.001). When SSWA was present in the PT cohort (n = 48 patients, n = 59 ears), in 31 cases (64.6%), the SSWA correlated with PT laterality (e.g., left SSWA, left PT); in 12 (25.0%), SSWA partially correlated with PT laterality (e.g., bilateral SSWA, right PT); and in 5 (10.4%), the SSWA did not correlate with PT laterality (e.g., right SSWA, left PT).

CONCLUSIONS

For our patients with both PT and SSWA, the SSWA is likely a contributing factor in approximately 65% of cases. For a third of patients with PT and concomitant SSWA, the association between the two is either not causative or not solely causative. Surgeons counseling patients with PT and SSWA may be optimistic overall regarding sigmoid resurfacing procedures but must appreciate the possibility of treatment failure, likely because of untreated comorbid conditions.