Pulsatile tinnitus (PT) is a rhythmic sound heard in the ear that is synchronized with one’s own heartbeat or pulse. This sound is often described as a whooshing, thumping, or throbbing noise, caused by blood moving through nearby vessels. While common tinnitus (a continuous ringing or buzzing) is typically a benign sensory issue, the rhythmic nature of PT suggests a physical, mechanical cause involving blood flow or pressure. Because this sound signals an audible change in the body’s circulatory system near the ear, the medical community treats PT as an indication of a potential underlying condition that requires prompt investigation.
Why Pulsatile Tinnitus Is Different
The experience of pulsatile tinnitus differs fundamentally from the continuous, high-pitched ringing associated with non-pulsatile tinnitus. Non-pulsatile cases usually originate from damage to the sensory hair cells in the inner ear, creating a phantom sound. In contrast, PT is almost always a mechanical event caused by turbulent blood flow or an increased awareness of normal flow transmitted to the ear. The sound of PT is frequently “objective,” meaning a clinician can sometimes hear the sound with a stethoscope placed over the neck or near the ear. This audibility confirms that the sound is physically generated within the body, establishing a direct link to the cardiovascular system.
Vascular Conditions Driving the Sound
The most common causes of pulsatile tinnitus involve conditions that create turbulent blood flow in the arteries and veins near the ear. When blood flow is restricted or forced through an abnormal pathway, the resulting turbulence is perceived as a pulsing sound. These vascular causes are typically categorized into arterial, venous, and arteriovenous abnormalities.
Arterial Causes
Arterial causes often stem from atherosclerosis, a narrowing of the carotid or vertebral arteries in the neck due to plaque buildup. This stenosis forces blood to rush through a smaller opening, resulting in a louder, more forceful sound. Vascular tumors, such as glomus tumors, are highly vascularized masses that can grow in the middle ear or along the jugular vein, creating significant turbulence. The high blood supply of these masses generates a distinct, pulse-synchronous sound localized to one ear.
Arteriovenous Malformations
Another serious cause involves arteriovenous malformations (AVMs) or fistulas, which are abnormal connections that bypass the capillaries, allowing arteries to dump high-pressure blood directly into veins. This high-velocity flow creates a loud bruit heard as pulsatile tinnitus and carries an inherent risk of hemorrhage.
Venous Causes
Venous issues affect the large veins that drain blood from the brain. These include abnormalities like a sigmoid sinus diverticulum, an outward pouching of the sigmoid sinus vein located near the inner ear. The turbulent swirling of blood in this pouch creates a whooshing sound transmitted to the ear drum. Identifying whether the sound is arterial or venous helps guide subsequent imaging.
Intracranial Pressure Changes
Changes in the pressure surrounding the brain primarily affect the venous drainage system. Idiopathic Intracranial Hypertension (IIH), also known as pseudotumor cerebri, is a significant cause of pulsatile tinnitus, particularly among obese women of childbearing age. In IIH, the pressure of the cerebrospinal fluid increases. This elevated pressure is transmitted to the large veins inside the skull, specifically the transverse and sigmoid venous sinuses. The increased external pressure causes them to narrow, a condition known as venous sinus stenosis. As blood is forced through these constricted veins, the flow becomes turbulent, generating the whooshing sound. The presence of PT in IIH is concerning because the elevated intracranial pressure can compress the optic nerve, leading to papilledema and potential vision loss if left untreated. Consultation with a specialist is urgent to prevent long-term complications.
The Necessary Steps for Diagnosis
The evaluation of pulsatile tinnitus begins with a thorough physical examination to determine if the sound is objective. The physician will use a stethoscope to auscultate over the ear, neck, and mastoid bone to detect a vascular noise, or bruit. A key part of the initial assessment involves a gentle compression test of the jugular vein, where a temporary reduction or cessation of the sound can suggest a venous origin. Because the causes require detailed visualization of blood vessels, imaging tests are an indispensable step. Magnetic Resonance Angiography (MRA) and Computed Tomography Angiography (CTA) are common tools used to visualize the arteries and veins of the head and neck. These tests can reveal arterial narrowing, aneurysms, vascular tumors, or structural abnormalities of the venous sinuses. Referral to a specialist, such as an otolaryngologist, neurotologist, or neurologist, is necessary to interpret these complex imaging results. If Idiopathic Intracranial Hypertension is suspected, further evaluation may include an eye exam to check for swelling of the optic nerve, and sometimes a lumbar puncture to directly measure the cerebrospinal fluid pressure.