Conditions: Pulsatile Tinnitus

Types of tinnitus

While people may experience various types of phantom sounds in their ears, including humming, buzzing, clicking, sound of crickets, etc., the two main categories are pulsatile tinnitus and non-pulsatile tinnitus. Pulsatile tinnitus (also called “pulse synchronous tinnitus”) has a rhythm that corresponds to one’s heartbeat. This is often because turbulent flow of blood creates noise, similar to the way a kinked garden hose makes sound. Unlike a kinked garden hose, flow of blood in an artery is rhythmic, hence the rhythmic generation of rhythmic sound. Non-pulsatile tinnitus includes all other types of tinnitus (ringing, humming, buzzing, etc.), and is more common.

subtypes and specific causes of pulsatile tinnitus

The many potential causes for pulsatile tinnitus may be divided into a few broad categories. One common method for categorizing causes of pulsatile tinnitus is according to the blood vessel involved: artery, vein, or the connection between arteries and veins (arteriovenous).

Blood flow through a vein: The venous causes of pulsatile tinnitus are abnormalities in the shape of a major vein draining the brain (the jugular bulb), presence of an aneurism or a narrowing of a large vein at the back of the skull (transverse–sigmoid sinus stenosis), abnormally large veins passing from the brain through the skull to the scalp (condylar and mastoid emissary veins), and increased pressure inside the skull (idiopathic intracranial hypertension). Venous pulsatile tinnitus is often described as having a quality of a low pitched “whooshing” sound and can be modified by certain neck maneuvers. In particular, compression of the internal jugular vein or suboccipital venous plexus on the side of the pulsatile tinnitus can lessen symptoms, while compression of the internal jugular vein on the other side of the neck can worsen symptoms. A venous hum is sound from the vibration of the thin walls of a vein as blood flows through it.

Turbulent flow in an artery or the connection between arteries and veins near inner ear may cause sound. Common causes of pulsatile tinnitus at the connection between arteries and veins (arteriovenous junction) include arteriovenous malformations/fistulas and highly vascularized skull base tumors.

Blood flow through an artery: Turbulent and noise-generating blood flow through an artery may be due to narrowing of the artery from atherosclerosis or fibromuscular dysplasia, an especially tortuous (twisted) course of the internal carotid artery, glomus tumors, a peeling off of the internal lining of the internal carotid artery (carotid artery dissection); carotid artery aneurysm and stenosis of the aortic heart valve. Conditions increasing blood flow through arteries, such as anemia, pregnancy, hyperthyroidism, or medications (including caffeine) may generate pulsating sound. Rarely, a inflammation of the arteries, as with Takayasu disease, may cause pulsatile tinnitus.

A pulsing blood vessel making contact with the auditory nerve may cause the perception of sound. This is similar to the way hitting one’s “funny bone” (ulnar nerve) at the elbow stimulates the nerve and the brain perceives sensation from the hand. Compression of the auditory nerve from variant anatomy of the anterior inferior cerebellar artery (AICA) or the posterior inferior cerebellar artery (PICA) can make the brain perceive pulsatile sound.

Nonvascular causes of pulsatile tinnitus include some that are not pulse synchronous, such as twitching of a nearby muscle (including the stapedius muscle or tensor tympani, forms of middle ear myoclonus; the tensor veli palatini; and the superior pharyngeal constrictor muscle). A dehiscence of the superior semicircular canal, Paget’s disease, and temporal bone trauma do relate to transmission of sounds of bloodflow, but are primarily caused by something outside the blood vessels. Neurologic conditions causing pulsatile tinnitus include a stroke/cerebrovascular accident, and multiple sclerosis. Otosclerosis, temporomandibular joint (TMJ) dysfunction, and tension in larger neck muscles have also been found to rarely cause pulsatile tinnitus.