Pseudotumor Cerebri and Jugular Foramen Syndrome

Aristides Sismanis and David R. Salley

Department of Otolaryngology-Head and Neck Surgery, Virginia Commonwealth University Medical Center, Richmond, Virginia, U.S.A.

■ Pseudotumor Cerebri Syndrome 344

■ Introduction 344

■ Definition 344

■ Epidemiology 344

■ Pathogenesis 344

■ Clinical Manifestations 346

■ Diagnosis 346

■ Treatment 348

■ Complications 349

■ Prognosis 349

■ Jugular Foramen Syndrome 349

■ Introduction 349

■ Definition 349

■ Etiology and Epidemiology 350

■ Pathogenesis 350

■ Anatomy of the Jugular Foramen 350

■ Clinical Manifestations 351

■ Diagnosis 351

■ Treatment 353

■ Complications and Prognosis 355

■ References 356

PSEUDOTUMOR CEREBRI SYNDROME INTRODUCTION

Pseudotumor cerebri (PC) syndrome may present with otologic/neurotologic manifestations; therefore, otolaryngologists should be familiar with this entity, in order to establish early diagnosis and apply effective treatment.

DEFINITION

PC syndrome is a disorder characterized by increased intracranial pressure (ICP), normal cerebrospinal fluid (CSF) content, and absent neurologic signs, except for occasional V, VI, and VII cranial-nerve palsies. In the majority of cases, the etiology is unknown (1,2). Other synonyms of this disorder are idiopathic intracranial hypertension syndrome and benign intracranial hypertension syndrome, although the latter term is being used less often, because of the risk of visual loss.

EPIDEMIOLOGY

The annual incidence of PC syndrome has been estimated to be 0.9 per 100,000 people in the general population. This entity is more common in young African American females who are 20% or more above their ideal body weight (3-5). In males, this disorder is very rare. In 25% of patients, it may become chronic (2).

ETIOLOGY

The various etiologies of this entity are summarized in Table 1 (1,6-9). PATHOGENESIS

Significant uncertainty exists regarding the pathophysiology of PC syndrome. Many studies have attempted to elucidate the underlying cause, often with conflicting results. Proposed theories include increased CSF production, cerebral edema, decreased CSF absorption, and elevated cerebral venous pressure (1,4,7,10,11). The latter theory is supported by the following studies: Anatomic obstruction of the venous transverse sinuses has recently been reported in PC patients; and direct retrograde cerebral venography with manometry has been recommended, in order to establish diagnosis (12,13). In another study, autotriggered elliptic-centric-ordered three-dimensional gadolinium-enhanced magnetic resonance veno-graphy (ATECO MRV) identified bilateral sinovenous stenosis in 27 of 29 patients with PC syndrome and in only 4 of 59 controls. It was not clear whether stenosis was a cause or effect of intracranial hypertension (14). There is evidence that in obese patients with PC syndrome, increased intracranial venous pressure most likely results from increased intra-abdominal, intrathoracic, and cardiac filling pressures (15). This pathophysiologic mechanism is further supported by an animal study demonstrating increased CSF pressure when intra-abdominal pressure was acutely raised (16).

Increased cerebral blood flow secondary to cerebrovascular resistance changes and CSF hypersecretion induced by elevated estrogen levels also have been reported as pathophysiologic mechanisms of PC syndrome (17).

TABLE 1 Etiologies of Idiopathic Intracranial Hypertension Syndrome

Medications

Obstruction of venous drainage

Amiodarone

Cerebral venous thrombosis

Anabolic steroids

Hypercoagulable states

Chlordecone

Antiphospholipid antibody syndrome

Corticosteroids

Polycythemia

Cyclosporine

Mastoiditis

Diphenylhydantoin

Superior vena cava syndrome

Divalproate

Increased right heart pressure

Growth hormone

Bilateral radical neck dissection

Indomethacin

Leuprorelin acetate

Circulatory and hematologic

Levothyroxine

Iron-deficiency anemia

Lithium carbonate

Sickle-cell anemia

Minocycline

Pernicious anemia

Nalidixic acid

Gastrointestinal hemorrhage

Norplant

Cryofibrinogenemia

Penicillin

Sulfa antibiotics

Systemic disorders

Tetracyclines and related compounds

Lupus erythematosus

Vitamin A

Sickle-cell anemia

All-trans retinoic acid

Sarcoidosis

Sleep apnea

Endocrine disorders

Turner's syndrome

Adrenal insufficiency

Human immunodeficiency virus infection

Hypoparathyroidism

Paget's disease

Hyperthyroidism

Galactosemia

Obesity

Head trauma

Menarche

Nephrotic syndrome

Menstrual irregularities

Uremia

Pregnancy

Infectious

Polycystic ovary syndrome

Lyme disease

Infectious mononucleosis

Nutritional disorders

Hypervitaminosis A

Hypovitaminosis A

Hyperalimentation in nutritional deficiency

The origin of pulsatile tinnitus (PT) in PC syndrome is secondary to the systolic pulsations of the CSF, which originate mainly from the arteries of the Circle of Willis. These pulsations, which are increased in magnitude in the presence of intracranial hypertension, are transmitted to the exposed medial aspect of the dural venous sinuses (transverse and sigmoid) and compress their walls synchronously with the arterial pulsations (3,18). The resulting periodic narrowing of the lumen converts the normal laminar blood flow to turbulent, which results in a low-frequency PT (3).

The low-frequency sensorineural hearing loss seen in many of these patients is secondary to the masking effect of the PT. This is supported by the fact that light digital compression over the ipsilateral internal jugular vein (IJV) results in cessation of the tinnitus and immediate improvement or normalization of hearing (3).

Stretching or compression of the cochlear nerve and brain stem, caused by the intracranial hypertension and/or possible edema, may also play a role in the hearing loss and dizziness encountered in these patients. This is supported by the abnormal auditory brainstem evoked responses (ABR) present in one-third of these patients (19).

CLINICAL MANIFESTATIONS

Although the classic presentation of PC syndrome consists of headaches and/or visual disturbances, PT alone or in association with hearing loss, dizziness, and aural fullness have been reported as the main manifestation(s) of this entity (3). Otolaryngologists, therefore, should be familiar with this syndrome, because these patients may present to them with the aforementioned symptomatology.

Headaches are described more often in the frontal region, are worse in a recumbent position and in the early morning hours, and may improve during the day.

Visual disturbances consist mainly of transient visual obscuration (short-duration episodes of visual clouding in one or both eyes). Visual obscurations are not a patho-gnomonic sign of PC syndrome, since they can occur with all etiologies of increased ICP with papilledema. They can also be present in patients without increased ICP, who have elevated optic discs from other causes.

DIAGNOSIS

Diagnosis of PC syndrome is made by exclusion of other causes of intracranial hypertension and is established by lumbar puncture (LP) and confirmation of CSF pressure of more than 200 mm of water with normal CSF constituents. Table 2 summarizes the modified Dandy criteria upon which diagnosis is based (20).

Consultation with a neuro-ophthalmologist or a neurologist is imperative for these patients.

Many of these patients are morbidly obese (body weight more than 100 lbs above ideal weight) and have an audible bruit in the ear canal and retroauricular area. Upon application of light digital pressure over the ipsilateral IJV, the bruit subsides (venous). Figure 1 depicts a typical PC syndrome patient who presented with PT. The remainder of the examination is usually normal.

Typically, PC syndrome patients have associated papilledema; however, absence of papilledema does not exclude this entity (21-23). In our experience, the majority of patients presenting with PT due to PC syndrome have no associated papilledema, and for this reason, some neurologists have been hesitant to perform LP and CSF measurement on these patients (24). It is therefore imperative for otolaryngologists to insist that this test be performed, in order to establish diagnosis.

Other serious comorbidities, such as diabetes mellitus, hyperlipidemia, hypertension, and obstructive sleep apnea, are common in patients with morbid obesity, and always deserve medical attention (25).

TABLE 2 Modified Dandy Criteria

An awake and alert patient

Presence of signs and symptoms of increased ICP

Absence of localized findings on the neurologic examination except paresis of abducens nerve Normal cerebrospinal fluid findings except for increased pressure Absence of deformity, displacement, and obstruction of the ventricular system on neuroimaging studies No other cause of increased ICP identified

Abbreviation: ICP, intracranial pressure. Source: From Ref. 3.

FIGURE 1 Pseudotumor cerebri patient.

Pure-tone (air and bone conduction) and speech audiometry should be performed in suspected cases. In cases with hearing loss in the low frequencies, something that can mimic Méniere's disease, a repeat audiogram should be obtained while the patient is applying light digital pressure over the ipsilateral IJV. This maneuver typically results in improvement or normalization of pure tones in patients with PT due to PC syndrome, because of elimination of the masking effect of the tinnitus (3). Discrimination is typically excellent in these patients. Figure 2A and B are representative audiograms of a patient with PT and PC syndrome.

Electronystagmography should be considered in cases with associated dizziness (3).

Neuroimaging is of utmost importance in the evaluation of these patients and always should precede LP. Patients suspicious for PC syndrome (young, obese females with PT) should undergo a brain magnetic resonance imaging (MRI) study combined with an MRV at their initial evaluation. Although in the literature, MRI findings of PC syndrome have been reported as normal in the majority of patients (26) (with the exception of an empty sella and/or small ventricles), a controlled study of 20 such patients disclosed flattening of the posterior sclera in 80% of patients, empty sella in 70%, distension of the perioptic subarachnoid space in 45%, enhancement of the prelaminar optic nerve in 50%, vertical tortuosity of the orbital optic nerve in 40%, and intraocular protrusion of the prelaminar optic nerve in 30% (27). Head MRV is obtained to eliminate stenosis/obstruction of the dural venous sinuses (12-14,28).

Serologic testing should be individualized and may include erythrocyte sedimentation rate, thyroid function tests, electrolytes, calcium, phosphorous, blood urea nitrogen (BUN), creatinine, serum cortisol, serum vitamin A level, and antinuclear antibodies (26).

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FIGURE 2 (A) Audiogram of a patient with PT and pseudotumor cerebri syndrome. Left low-frequency hearing loss is present. (B) Normalization of hearing loss while digital pressure is applied over the right internal jugular vein and the masking PT is eliminated. Abbreviation: PT, pulsatile tinnitus.

TREATMENT

The goals of management are to normalize ICP, prevent loss of vision, relieve PT and headache, and treat comorbidities.

Since the majority of these patients are obese females, some even morbidly obese, it is very important to make them aware of the relationship between their body weight and PC syndrome. Consultation with a dietician is essential; weight reduction results in decrease or resolution of symptoms (29).

Comorbidities, such as obstructive sleep apnea, gastroesophageal reflux, hypertension, diabetes mellitus, and hyperlipidemias, should be detected early on and addressed aggressively, as well.

Acetazolamide inhibits choroid plexus carbonic anhydrase and reduces CSF production by 50% to 60% (30). The recommended dose is 250 mg three times a day or 500 mg twice a day (31). PT may decrease with this treatment; however, it seldom subsides unless it is combined with weight loss.

Recently there has been some anecdotal evidence that the antiepileptic medication Topamax® (topiramate) is effective in PC syndrome. One of topirimate's mechanisms of action is inhibition of carbonic anhydrase, although this effect is weaker than that of acetazolamide. Furthermore, a potential side effect of Topamax is weight loss, which would be beneficial to many PC patients. Currently, we have no clinical experience with topiramate at our institution.

Furosemide (Lasix) has little effect on PC syndrome when given alone, but it has been used as an adjunct to acetazolamide (30).

Corticosteroids can rapidly lower ICP, but since their long-term use has the opposite effect (20), they are rarely indicated.

A lumbar peritoneal shunt should be considered for PC syndrome patients with progressive deterioration of vision, persistent headaches, and disabling PT (3,26,31,32). In morbidly obese patients, however, this procedure is often complicated by occlusion of the shunt secondary to increased intra-abdominal pressure (33).

Optic nerve sheath fenestration is helpful for progressive visual loss and headaches (31,34).

For morbidly obese patients who have failed to lose weight with dieting, effective weight loss can be achieved with bariatric surgery. Out of 16 patients who underwent this procedure, 13 experienced complete resolution of PT (35). A substantial majority of patients with obstructive sleep apnea, hyperlipidemia, hypertension, and diabetes mellitus experienced complete resolution or improvement following this type of surgery (25).

Recently, resolution of symptoms has been reported following retrograde venography and stenting of the transverse sinus in PC syndrome patients with associated stenosis/ obstruction of this structure (12,13,28).

The cooperation of an experienced neuro-ophthalmologist or neurologist, internist, ophthalmologist, dietician, and general surgeon is of utmost importance.

COMPLICATIONS

Visual problems are the most serious complications of PC syndrome and may include decreased visual acuity and visual field deficits. Loss of vision may precede the diagnosis or may occur after several years (20). Associated comorbidities such as diabetes mellitus, hyperlipidemia, hypertension, and obstructive sleep apnea may have disastrous results if left untreated.

PROGNOSIS

For patients with PC syndrome who lose weight, the prognosis is good. It has been reported that in 25% of patients, this entity may become chronic (2).

SUMMARY

Patients with PC syndrome may first present to an otolaryngologist with PT and other otologic/neurotologic symptoms. Associated comorbidities such as diabetes mellitus, hyperlipidemia, hypertension, and obstructive sleep apnea should be detected early and addressed aggressively. A team approach with a neuro-ophthalmologist or neurologist, ophthalmologist, internist, dietician, and general surgeon is of utmost importance.

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