FLEX January 2024

Review Clinical Review & Education

Diagnostic Approach to Pulsatile Tinnitus

Figure 4. Transverse Sinus Stenosis

Axial MRV of right transverse sinus A

Repeat MRV B

Right-sided pulsatile tinnitus. A, Axial contrast-enhanced magnetic resonance venogram (MRV) demonstrates intrinsic stenosis of the right transverse sinus (asterisk) owing to arachnoid granulation. After removal of 20 mL of cerebrospinal fluid (CSF) via lumbar puncture, pulsatile tinnitus resolved and B, repeated axial contrast-enhanced MRV demonstrates resolution of stenosis (asterisk). Therefore, the stenosis may resolve with acetazolamide therapy. C, Coronal phase-contrast magnetic resonance angiogram (MRA) of model of venous sinus before CSF removal demonstrates elevated flow velocities through the stenosis (arrowhead) as the likely cause of pulsatile tinnitus. D, Coronal phase-contrast MRA of model of venous sinus after CSF removal demonstrates normal flow velocities (arrowhead) when the stenosis is reduced. Panels C and D are reproduced with permission. 10

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Coronal MRV before CSF removal C

Repeat MRV after CSF removal D

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include acupuncture and physical therapy directed at improving cervi cal muscular tension and range of motion. Idiopathic intracranial hypertension is commonly associated with bilateral stenoses of the transverse-sigmoid sinuses. Along with op tic nerve sheath distention or tortuosity, empty sella, enlarged tri geminal nerve cisterns, and meningoceles in the sphenoid wing and temporal bone, these patients may develop SSCD or CSF otorrhea/ rhinorrhea. Idiopathic intracranial hypertension has an incidence of 20 per 100 000 overweight women of childbearing age, with in creasing prevalence owing to the obesity epidemic. Characteristic clinical features include a headache worse with dependent posi tioning (eg, when bending over to tie shoes), transient or gradual vision loss, and low-pitch, pulse-synchronous PT. Elevated intracra nial pressure owing to a mass or arteriovenous fistula must be ex cluded, as part of the modified Dandy criteria, prior to diagnosis of IIH. 23 Lumbar puncture opening pressure is needed to establish di agnosis. We also obtain magnetic resonance venography before and after removal of 20 mL of CSF to establish whether the transverse sigmoid sinus stenoses improve after CSF removal and ICP lower ing (Figure 4). For most patients with IIH, first-line treatment con sists of weight loss and acetazolamide. 24 For patients with IIH with worsening vision loss or headache who have failed or are intolerant to medical therapy, operative interventions that could be consid ered include venous sinus stenting, optic nerve sheath fenestra tion, CSF diversion, or bariatric surgery. Compared with other op erations, venous sinus stenting offers a favorable risk-to-benefit ratio because of its efficacy in improving visual fields, papilledema, and

signifies atherosclerotic disease in the elderly, or fibromuscular dyspla sia or dissection in the young, with noninvasive imaging playing a piv otal role in establishing the diagnosis ( Figure3 ). Aortic stenosis in an el derly patient is heard as a systolic murmur and typically causes right PT. Aneurysms of the vertebral or internal carotid artery can also lead to tur bulent blood flow and PT. Carotid cochlear dehiscence is a rare cause of PT that is typically seen only on temporal bone CT, but it remains un clear how a congenital abnormality can result in symptom development in the third or fourth decade of life. Venous causes of PT are suspected when patients have a low pitched, pulse-synchronous sound that improves with ipsilateral jugu lar vein compression. These can result from turbulent flow in diverticula of the sigmoid sinus or jugular bulb, enlarged condylar veins, stenoses in the transverse sinus ( Figure4 ), sigmoid sinus, and internal jugular vein, or a high-riding jugular bulb. 19-21 If an anatomic abnormality is detected, it is imperative to ensure that the patient’s symptoms are attributable to altered blood flow resulting from the abnormality, including the side of the patient’s symptoms. In this regard, when a venous cause of PT is suspected, we find cerebral venous manometry and balloon test oc clusion to be a critical part of the diagnostic evaluation that guides sub sequent treatment. This detailed evaluation is typically performed with the patient awake to accurately assess intracranial venous pressures and subjective PT. Various treatment strategies have been described to ad dress these abnormalities, including endovascular treatments such as stenting or coil embolization, as well as open surgical techniques such as sigmoid sinus resurfacing. 22 Conservative treatments for PT caused by internal jugular vein stenosis or associated enlarged condylar veins

(Reprinted) JAMA Otolaryngology–Head & Neck Surgery May 2022 Volume 148, Number 5 481

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