Tinnitus is the perception of sound within the ear or head without an external source. Pulsatile tinnitus (PT) is a specific type characterized by a rhythmic whooshing, thumping, or heartbeat sound synchronized with the patient’s pulse. The temporary cessation of this sound when gentle pressure is applied to the side of the neck is a significant clinical finding. This relief maneuver suggests the sound is generated by a process involving the blood vessels in the neck or head.
Understanding Pulsatile Tinnitus
Pulsatile tinnitus differs fundamentally from typical tinnitus, which is often linked to auditory nerve damage. PT is frequently an objective phenomenon, meaning a clinician can sometimes hear the sound using a stethoscope near the ear or neck. This indicates that PT is a mechanical sound originating from a nearby source, rather than a problem with the ear itself.
The source of the sound is almost always the flow of blood through nearby arteries or veins. Turbulence or an alteration in blood flow volume or velocity near the inner or middle ear structures creates noise. This intrinsic sound is transmitted through surrounding tissues and bone to the cochlea, registering as a pulsing noise synchronized with the heartbeat.
The Mechanism of Temporary Relief
The temporary disappearance of PT when pressing the neck is a defining characteristic and a strong indicator of its specific cause. This simple test, the neck compression test, directly demonstrates a venous origin for the sound. Applying gentle pressure compresses the internal jugular vein, the primary vessel draining deoxygenated blood from the head.
Compressing the jugular vein temporarily decreases the volume and velocity of blood flow returning to the heart. This reduction immediately lessens the turbulence within the nearby venous sinuses and veins adjacent to the ear structures. The turbulent flow, the source of the whooshing sound, is briefly quieted by the change in pressure and flow dynamics. The sound returns immediately when pressure is released, allowing normal blood flow to resume.
This relief maneuver confirms the pulsatile sound is not caused by an arterial issue, such as a carotid artery aneurysm or dissection, which would not be relieved by jugular vein compression. The temporary silencing of the sound is a valuable diagnostic tool that directs the investigation toward conditions affecting the venous system. It indicates the sound is generated by a high-flow, low-resistance system, characteristic of venous pathology.
Vascular Conditions Associated with Compressible PT
The underlying causes of PT relieved by neck compression relate to structural or flow abnormalities in the venous system near the ear. A common benign cause is Venous Hum, which involves turbulent blood flow in the jugular vein, often due to increased blood volume or a change in the vessel’s structure.
Structural variations within the head and neck can also lead to compressible PT, such as a High-Riding Jugular Bulb or a Sigmoid Sinus Diverticulum. If the jugular bulb sits abnormally high or has a thin bony wall (dehiscence) near the middle ear, the sound of blood flow can be amplified. A sigmoid sinus diverticulum is an abnormal outpouching of the large vein channeling blood toward the jugular vein, which can also generate sound.
A more significant cause of venous PT is Idiopathic Intracranial Hypertension (IIH), also known as pseudotumor cerebri. IIH involves increased cerebrospinal fluid pressure, often leading to stenosis (narrowing) of the large venous sinuses. This narrowing increases the speed and turbulence of blood flow, which is perceived as pulsatile tinnitus. IIH is often associated with headaches and visual changes.
Necessary Diagnostic Steps and Next Actions
Since the symptom suggests a vascular cause, a medical evaluation is required to determine the specific underlying condition. The first step involves consultation with an otolaryngologist (ENT) or a neuro-otologist. These specialists perform a comprehensive physical and audiological examination, including the neck compression test, to confirm the venous nature of the tinnitus.
Following the initial assessment, specialized diagnostic imaging is ordered to visualize the blood vessels and surrounding structures. Magnetic Resonance Angiography (MRA) and Magnetic Resonance Venography (MRV) evaluate the arteries and veins for narrowing, malformations, or unusual flow patterns. A Computed Tomography (CT) scan of the temporal bone is also used to identify structural issues like a high-riding jugular bulb or bony dehiscence near the ear.
Further evaluation may include consultation with a neuro-interventional radiologist or a neurologist, especially if Idiopathic Intracranial Hypertension or dural arteriovenous fistulas are suspected. Treatment is highly specific and depends entirely on the underlying cause identified. For instance, venous sinus stenosis may be treated with medication to reduce intracranial pressure or, in some cases, with a stent to widen the vessel.