Pearls from Your Peers: Pulsatile Tinnitus
Erika McCarty Walsh, MD, interviewed Philip Schmalz, MD, on pulsatile tinnitus, a pulse-synchronous sound.
Philip Schmalz, MD, is a neurosurgeon and assistant professor at the University of Alabama at Birmingham. He has extensive experience in neurocritical care disorders, and his clinical interests include cerebrovascular, endovascular, and skull base surgery. Erika McCarty Walsh, MD, is a neurotologist specializing in lateral skull base surgery, implantable hearing devices, and chronic ear disease. She treats the full spectrum of neurotology patients, including children and adults with hearing loss, chronic ear infections and cholesteatoma, vestibular disorders, and benign and malignant tumors of the skull base.
How do you define pulsatile tinnitus?
Pulsatile tinnitus is a pulse-synchronous sound, often described as a “whoosh.” It may be intermittent or constant, and while often bilateral, it usually has a lateralized component. When vascular in origin, it represents an audible bruit from turbulent blood flow near the ear. The most frequent causes are venous, including venous sinus stenosis, dehiscence, or diverticulum, though hyper-vascular tumors and dural arteriovenous fistulae (dAVFs) must also be considered. Non-vascular mimics, such as middle ear myoclonus or superior semicircular canal dehiscence, are in the differential but often present differently.
How worrisome is pulsatile tinnitus as a symptom?
Pulsatile tinnitus affects an estimated three to five million people in the United States. Patients often fear aneurysms or vascular malformations, but most vascular causes are venous and relatively benign unless accompanied by visual changes suggesting intracranial hypertension. Still, all patients should be evaluated by a multidisciplinary team including otologists, neurosurgeons, and neurointerventionists. Workup includes detailed history and exam, audiogram, and imaging. It is important to note that even if the cause is not life-threatening, such as with venous stenosis, pulsatile tinnitus can have a profound impact on quality of life and can frequently be treated. Historically, in up to 30% of patients, no diagnosis can be found, though this appears to be changing with both greater recognition of the condition, improved imaging, and improved interventional technology, particularly for venous sinus stenosis.
What is a neurosurgeon’s role on a multidisciplinary team caring for patients with pulsatile tinnitus?
The neurosurgeon’s role is to help determine the sound generator, to rule out higher-risk diagnoses, and ultimately provide treatment if the cause can be found. Many etiologies—such as paragangliomas, venous sinus stenosis due to intracranial hypertension, and dAVFs—fall squarely in the neurosurgical domain. Management may involve venous stenting, treatment of arterial stenosis, or management of hyper-vascular tumors with surgery or radiation. Subspecialty training in skull base, endovascular, and cerebrovascular surgery provides the breadth of expertise needed to manage these diverse conditions.
How are patients with pulsatile tinnitus evaluated by your team?
History and physical examination are key. I focus on the sound’s character, setting, laterality, and changes with maneuvers such as jugular compression or head turning, the latter being particularly key for venous pathology such as sinus dehiscence or stenosis. Additional symptoms such as headache or visual decline are important when considering intracranial hypertension. Careful assessment helps distinguish venous symptoms from more concerning pathology and avoids unnecessary invasive testing. An arterial bruit on auscultation of the mastoid is a key finding prompting vascular imaging, often digital subtraction angiography (DSA).
In addition to the history, our evaluation includes temporal bone CT, CT angiogram of the head and neck (CTA), audiogram, and, often, contrast-enhanced MRI with thin-slice post-contrast T1 sequences (e.g., MPRAGE). These studies detect tumors, secondary signs of intracranial hypertension, and evaluate the venous sinuses. DSA is reserved for persistent diagnostic uncertainty and remains the gold standard for dAVFs.
What are the “can’t miss” or critical causes of pulsatile tinnitus?
Critical diagnoses are hyper-vascular tumors such as paragangliomas, arterial stenosis and arteriovenous malformations (AVMs), and dAVFs. Arterial stenosis and AVMs are readily diagnosed with axial imaging. Paragangliomas are usually apparent on MRI and/or CT at experienced centers, though small lesions may be overlooked. Dural arteriovenous fistulae are rare but high-risk, associated with intracranial hemorrhage, seizures, and cognitive decline from venous hypertension. Unfortunately, CTA or standard MRA is insufficient for diagnosis, though there are often subtle clues that can prompt further investigation with DSA. Advanced MRA techniques (e.g., TRICKS or “silent” MRA) approach DSA in sensitivity but are not widely available. At our center, DSA remains the diagnostic standard when a dAVF is suspected.
