Hearing a rhythmic thumping or whooshing sound synchronized with your heartbeat is known as pulsatile tinnitus (PT). This sensation differs from common tinnitus, which involves a continuous ringing or hissing noise that does not follow a pulse. PT is a “somatosound,” originating from within the body and becoming audible to the inner ear. The noise is created by the flow of blood through vessels near the ear structure, which is then transmitted to the hearing mechanism. Understanding the source of this internal sound is crucial for determining if it is a temporary annoyance or a sign of an underlying medical condition.
Understanding Pulsatile Tinnitus
PT is fundamentally different from standard non-pulsatile tinnitus, which is often a subjective phantom sound. PT is almost always objective, meaning it arises from a physical, vascular sound source inside the body. This sound is created by the movement of blood through arteries and veins located close to the auditory system, such as the carotid artery and the jugular vein.
The mechanism involves the transmission of sound from turbulent blood flow to the inner ear structures. Normally, blood flow is quiet and smooth, but any structural or functional change that causes the flow to become turbulent generates an audible pulse. Changes in blood velocity or vessel wall integrity easily transmit vibrations to the cochlea, resulting in the rhythmic throbbing noise.
Common Temporary Causes of Thumping
Many instances of pulsatile tinnitus are linked to temporary physiological changes that increase the speed or volume of blood flow, making the sound more noticeable. Conditions that cause a generalized increase in blood circulation make the heart’s rhythm more easily heard near the ear. For instance, strenuous exercise or high stress temporarily elevate heart rate and blood pressure, leading to a louder, more turbulent flow.
Anemia, characterized by a reduced number of red blood cells, increases blood flow velocity as the heart works harder to circulate oxygen. Similarly, hyperthyroidism accelerates the body’s metabolism and heart rate. These physiological causes are non-threatening and resolve once the underlying state returns to normal.
Other common, correctable causes relate to conductive hearing issues, which amplify internal body sounds by blocking external noise. The accumulation of cerumen (earwax) obstructs the ear canal, dampening ambient sound and making internal noises, like the pulse, significantly more apparent. Middle ear infections, such as otitis media, or fluid buildup can also create conductive hearing loss that increases the relative volume of nearby blood flow.
Vascular and Structural Underlying Conditions
While many causes are temporary, persistent pulsatile tinnitus often indicates a structural or vascular abnormality requiring detailed medical evaluation. One common structural issue is atherosclerosis, where fatty plaque deposits narrow the arteries near the ear. This narrowing forces blood through a restricted space, creating turbulence and the characteristic whooshing sound. The loss of elasticity in the vessel walls also contributes to a more forceful, audible pulse.
In the venous system, a condition known as venous hum is a frequent cause of PT, often resulting from a narrowing (stenosis) of a large vein in the brain, such as the sigmoid sinus. This stenosis disrupts the smooth flow of blood returning to the heart, generating a turbulent sound transmitted to the ear. Congenital variants, like a high-riding jugular bulb or a sigmoid sinus diverticulum, involve abnormal positioning or pouches on the vein wall that reduce the barrier between blood flow and the inner ear.
Idiopathic Intracranial Hypertension (IIH) involves elevated pressure of the cerebrospinal fluid surrounding the brain. This increased pressure can compress the veins that drain blood, causing stenosis and resulting turbulent flow. IIH is often associated with headaches and vision changes. Rare vascular tumors, such as glomus tumors, can also contribute to PT by being highly vascular and increasing local blood supply near the ear structures.
Seeking Medical Guidance and Diagnosis
If the throbbing sound is constant, worsening, or accompanied by neurological symptoms like dizziness, persistent headaches, or visual disturbances, a prompt visit to a physician is necessary. Since pulsatile tinnitus often signals an underlying physical change, the cause must be investigated. The diagnostic process typically begins with a physical examination, where the doctor may use a stethoscope to listen to the neck and skull.
If the clinician can hear the pulsing sound, it is categorized as objective pulsatile tinnitus, confirming a physical source. Initial testing includes an audiological exam to check for any associated hearing loss. Beyond the initial examination, imaging tests are often required to visualize the vascular structures near the ear.
Diagnostic imaging may include Magnetic Resonance Imaging (MRI) or Computerized Tomography (CT) scans to look for vascular malformations, tumors, or bone abnormalities in the temporal bone. In some cases, specialized procedures like angiography may be performed to provide a detailed image of the blood vessels and identify blockages, aneurysms, or abnormal connections. Identifying the specific source allows for targeted treatment, which may resolve the pulsatile tinnitus completely.