What is Acoustic Neuroma?
The term "acoustic neuroma" is the traditional medical description for a tumor that forms from Schwann cells located on the outside sheath of the 8th cranial vestibulocochlear nerve. Many healthcare professionals use the more accurate "vestibular schwannoma" because the word "acoustic" causes confusion about the tumor and related symptoms. This type of tumor typically affects more than a patient's hearing. As it grows, it spreads and compresses nearby nerves and structures within the skull. Approximately 2,000 to 3,000 patients receive this diagnosis yearly. Although usually noncancerous, a rare cancerous acoustic neuroma can form naturally. Additionally, some tumors become cancerous after radiotherapy.
What Are the Causes of Acoustic Neuroma?
Acoustic neuromas aren't currently well understood. Some patients have a genetic condition called Neurofibromatosis Type 2 or NF2 that causes bilateral growth. Most patients don't fit into this category. Various research studies worldwide have revealed that potential contributing factors possibly include:
- An unknown genetic condition
- A dysfunctional immune system related to stress or another underlying health condition
- Repeated exposure to loud noise or radiation
Researchers are still exploring similarities and differences in genetics, age, health, lifestyle, and other aggregate patient data factors. Given this tumor's rarity and the lack of absolute causation, patients often receive conflicting medical advice. That said, some doctors advise patients to limit exposure to stressful situations, loud noise, and dental and head X-rays.
What Are the Symptoms of Acoustic Neuroma?
The most common initial symptoms include ear fullness and pressure, hearing changes like tinnitus, reduced hearing, total hearing loss, physical imbalance, and vertigo. These are by no means the only symptoms. Some patients experience hyperacusis where they have difficulty tolerating normal low-level noise because certain sounds seem too loud. Since the tumor can compress the nearby 5th cranial or trigeminal nerve, some patients also experience facial numbness, tingling, or stabbing pain on the tumor side. With vestibular changes or growth in the cerebellopontine angle (CPA) that causes intracranial pressure fluctuations, some patients experience symptoms associated with other vestibular diseases and "brain" tumors including:
- High blood pressure
- Blood clots
- Autoimmune dysfunction
- Mood, personality, or cognitive changes
How is Acoustic Neuroma Diagnosed?
Patients usually believe that ear-related symptoms indicate a head cold, temporomandibular joint problem, or natural hearing loss from aging. Their family doctor, ENT, neurologist, or other specialist orders a CT or MRI scan. Some tumors have been discovered after an accident prompts an ER doctor to order one of these scans. Many patients go undiagnosed for years and only receive a scan after symptoms begin to impact their quality of life adversely or complain of symptoms typically associated with brain disease or tumors.
How is Acoustic Neuroma Treated?
With small, non-growing, or asymptomatic tumors, specialists often recommend a "watch and wait" plan where patients receive non-contrast or contrast MRIs at six-month or yearly intervals. With or without symptoms, doctors usually recommend one of two types of treatment: radiosurgery using targeted doses of radiation or skull-based microsurgery performed by a neurosurgeon and a neuro-otologist team. Patients also receive additional treatments related to coping, life skills, and recovery.
What Are the Complications of Acoustic Neuroma?
Beyond the complications mentioned, compression of structures that control basic processes like breathing can lead to death. Compression and surgical treatments can cause cerebral spinal fluid leaks, permanent nerve damage, facial paralysis, and vision problems. After skull-based microsurgery, some patients who have herpes simplex experience immediate or delayed facial paralysis because of the virus. Many patients deal with depression and difficulties related to a public misunderstanding about benign tumors and outward appearance. For example, when some patients have benign tumors or look healthy, many of their peers incorrectly believe that their struggles are mild compared to those of cancer patients. After treatment, some people even think that everything goes "back to normal." The truth is this tumor often forces patients to change their lives dramatically. Some patients continue to experience vestibular symptoms or a return of symptoms as they age, discover new tumor growth, or learn that they have a condition known as Schwannomatosis that causes Schwann cell tumors throughout the body.