What is different about pulsatile tinnitus?
On the contrary to constant tinnitus, pulsatile tinnitus presents as a rhythmic noise typically synchronised with the heart’s beat. It can be distinguished by palpating the pulse simultaneously while perceiving the tinnitus. Other types of tinnitus may involve rhythmic sounds, but they do not coincide with the pulse (see other forms of pulsatile tinnitus below). When medical professionals explore tinnitus cases, it is uncommon to pinpoint a singular identifiable cause for the issue. However, in the case of pulsatile tinnitus, the probability of identifying a specific cause is higher, although still challenging.
Causes of pulsatile tinnitus
Pulsatile tinnitus arises from alterations in blood flow either near the ear vessels or due to changes in awareness of that flow. These vessels can be found in the major arteries and veins in the neck and base of the skull, as well as smaller ones within the ear itself.
Various factors can contribute to this change in blood flow, though this list is not exhaustive. Individuals experiencing pulsatile tinnitus should seek medical evaluation.
- Generalized Increased Blood Flow: Conditions such as strenuous exercise, pregnancy, severe anemia, or hyperthyroidism (overactive thyroid gland) can lead to increased blood flow throughout the body, resulting in pulsatile tinnitus.
- Localized Increased Flow: In some cases, blood flow may be elevated in specific blood vessels rather than throughout the body. For instance, the persistence of the stapedial artery in the middle ear can generate pulsatile tinnitus in some individuals.
- Tumors of the Head and Neck: Abnormal blood vessel development due to tumors in the head and neck region can cause pulsatile tinnitus. These tumors are usually benign rather than malignant.
- Turbulent Blood Flow: Atherosclerosis, or hardening of the arteries, can lead to irregularities inside blood vessels, causing turbulent rather than smooth blood flow and resulting in noise.
- Altered Awareness: Conditions such as conductive hearing loss (e.g., perforated eardrum or glue ear) can heighten awareness of internal body sounds, contributing to pulsatile tinnitus. Similarly, heightened sensitivity in the auditory pathways can make the brain more alert to normal vascular noises.
- Other Causes: Some cases of pulsatile tinnitus don’t fit into the aforementioned categories. For example, benign or idiopathic intracranial hypertension, characterized by headaches, visual disturbances, and pulsatile tinnitus, predominantly affects overweight young or middle-aged women. However, it can occur in individuals of any age or gender, and its exact cause remains unknown.
How do we investigate pulsatile tinnitus?
A medical evaluation for pulsatile tinnitus typically commences with a comprehensive history-taking by the doctor, focusing on the tinnitus and any concurrent medical conditions. Subsequently, a physical examination is conducted, with particular attention given to the ear drums and the blood vessels in the neck.
The doctor may employ a stethoscope to listen to the neck and skull. If a pulsatile noise is audible through the stethoscope, it is termed objective pulsatile tinnitus. Conversely, pulsatile tinnitus that cannot be heard by the doctor is referred to as subjective pulsatile tinnitus. Additional assessments may include a hearing test, which is standard for any form of tinnitus.
Individuals with pulsatile tinnitus are typically referred for medical imaging. The choice of investigation is determined by the health professional in consultation with the patient, considering their medical history. Here’s an overview of the imaging methods commonly used:
Magnetic Resonance Imaging (MRI): This technique produces images of the head and inner ears using static magnetic fields and radio frequencies, without X-rays. MRI may be preferable for certain conditions, although some cases may require both CT and MRI scans.
Magnetic Resonance Angiography (MRA): MRA generates images of the inside of arteries or veins, identifying irregularities or narrowing. It may involve the injection of a contrast agent.
Computed Tomography (CT): CT uses X-rays to create detailed images of the head and neck.
Computed Tomographic Angiography (CTA): This method combines the injection of a contrast agent with CT scanning to produce detailed images of blood flow through the head and neck vessels.
Angiography: This procedure involves injecting contrast and taking X-rays to visualize the inside of the vessels.
Ultrasound: Ultrasound scanning, utilizing Doppler technique, assesses blood flow within the neck vessels. Similar to pregnancy scans, it involves applying a gel-like substance to the area and is a quick and painless procedure.
Additionally, blood tests may be necessary to investigate underlying causes of pulsatile tinnitus, such as full blood count to rule out anemia or thyroid function tests if hyperthyroidism is suspected. In cases of suspected benign intracranial hypertension, consultation with specialists like ophthalmologists or neurologists may be sought, who may recommend further specialized investigations.
What other forms of pulsatile tinnitus are there?
Myoclonus
Some cases of tinnitus involve rhythmic sounds that do not align with the individual’s heartbeat. This particular type of tinnitus often stems from the rhythmic contractions of muscles in the middle ear.
The tensor tympani and stapedius are two small muscles in the middle ear that can occasionally undergo rhythmic contractions, akin to the eye muscles twitching when fatigued. This phenomenon is termed myoclonus. In rare instances, rhythmic tinnitus may result from the contraction of certain muscles in the soft palate at the back of the throat. Individuals experiencing such tinnitus should consult a doctor, as there’s a slight chance of identifying an underlying cause. However, in most cases, no specific cause can be pinpointed.
Many individuals with this form of tinnitus can tolerate it once they comprehend that it’s not indicative of a serious condition. Alternatively, surgical procedures to sever the middle ear muscles or injecting botulinum toxin into the palatal muscles are potential treatments.
Patulous Eustachian Tube Syndrome
Patulous Eustachian Tube Syndrome presents as a rare form of tinnitus wherein individuals perceive variations in the tinnitus in sync with their breathing. They may also feel a sensation of ear blockage and experience an echoing of their voice inside their head.
This syndrome arises from the excessive openness of the Eustachian tube, the passage connecting the back of the nose to the inner ear. Normally closed, this tube briefly opens during actions like yawning or swallowing. If it remains abnormally open, changes in pressure caused by breathing transmit to the inner ear via the tube.
Many individuals associate the onset of this condition with sudden weight loss. Those suspecting they have this syndrome should seek medical advice. Treatment options include injections around the tube or altering the tube’s opening to reduce its size. Self-management techniques such as tinnitus sound therapy, relaxation therapy, cognitive-behavioural therapy (CBT), counselling, mindfulness meditation, or Tinnitus Retraining Therapy (TRT) can also offer relief.