A jugular bulb diverticulum is an outpouching of a major vein located near the ear, within the skull base. While often not causing issues, its presence can sometimes lead to health concerns depending on its size and location. This anatomical feature is frequently discovered incidentally during medical imaging for unrelated conditions, meaning many individuals live with it unknowingly.
What is Jugular Bulb Diverticulum
The jugular bulb is an enlarged part of the internal jugular vein, a large blood vessel draining deoxygenated blood from the brain, head, and neck. Situated at the skull’s base within the jugular foramen, it lies close to inner and middle ear structures. It acts as a connection point where major brain veins converge before continuing as the internal jugular vein.
A jugular bulb diverticulum is a protrusion or sac-like extension from this bulb. While often described as rare in older literature, recent studies suggest jugular bulb abnormalities, including diverticula, may be present in 1% to 8% of individuals on imaging. Some studies indicate a prevalence of 10% to 15% for jugular bulb variations generally. Many individuals with a diverticulum remain without symptoms, often an incidental finding during imaging for other reasons.
When It Causes Problems
A jugular bulb diverticulum can lead to symptoms when its size or position interferes with nearby sensitive structures within the skull base. The most common symptom is pulsatile tinnitus, a rhythmic whooshing or throbbing sound in the ear synchronous with the heartbeat. This occurs because the diverticulum can cause turbulent blood flow, and its proximity to the middle or inner ear allows the sound to be perceived.
Beyond pulsatile tinnitus, individuals might experience hearing loss, which can be either conductive or sensorineural. Conductive hearing loss can result if the diverticulum protrudes into the middle ear, interfering with sound conduction. Sensorineural hearing loss and vertigo may occur if the diverticulum erodes or presses upon inner ear structures. Less frequently, an enlarged diverticulum might compress adjacent cranial nerves, potentially leading to symptoms like facial weakness or other neurological deficits. The occurrence of these symptoms depends on the specific direction and extent of the diverticulum’s protrusion into surrounding anatomical spaces.
Identifying and Addressing It
Identifying a jugular bulb diverticulum typically involves specialized medical imaging. Computed Tomography (CT) scans are frequently used as an initial imaging study, providing detailed views of bone structures and showing the diverticulum’s extension. Magnetic Resonance Imaging (MRI) and venography techniques offer additional insights by visualizing blood flow and the diverticulum’s relationship to surrounding soft tissues and vascular structures. These imaging modalities help differentiate a diverticulum from other conditions that might present with similar symptoms.
Once a jugular bulb diverticulum is identified, management depends on whether the individual is experiencing symptoms. For those without symptoms, observation is often the recommended course, as many diverticula remain stable. Regular monitoring through follow-up imaging might be suggested to track any changes in size or position.
When symptoms are present and attributed to the diverticulum, intervention might be considered. Surgical options typically involve a transmastoid approach to reduce the diverticulum and reconstruct the bony wall. Endovascular treatments, such as stenting or coil embolization, represent less invasive alternatives, particularly for debilitating pulsatile tinnitus. The decision to intervene involves careful consideration of the specific symptoms, the diverticulum’s characteristics, and the potential benefits and considerations of the procedure.