An acoustic neuroma is usually benign, but it can still be fatal if left untreated. This is because the tumour will keep growing. Once it runs out of space inside the small canal that links the inner ear to the brain, it begins to grow into the skull cavity.
The tissue at the base of the brain, including a structure called the brain stem, may become squashed by the growing tumour. This can cause a build-up of fluid know as cerebral spinal fluid (CSF). The brain stem is responsible for regulating important bodily functions, including consciousness, heart rate, breathing, blood pressure and swallowing.
Inherited myopathies are myopathies that you’re born with when you inherit a genetic mutation from one of your parents. Inherited myopathies include:
Congenital myopathies. People with congenital myopathies often start to show symptoms when they’re a baby or child. These myopathies often involve developmental delays in learning motor skills, such as crawling or walking. It’s common for congenital myopathies to affect all of the skeletal muscles, and it often does not progress.
Mitochondrial myopathies. Mitochondrial myopathies are caused by mutations in the mitochondria, which are the “powerhouses” or energy-producing parts of the body’s cells. In addition to muscle weakness, they may also cause problems with the heart, brain, or gastrointestinal tract. Examples of mitochondrial myopathies include:
- Kearns–Sayre syndrome
- Mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome
- Myoclonic epilepsy with ragged red fibers (MERRF) Syndrome
Muscular dystrophies. Muscular dystrophies are characterized by progressive weakness in skeletal muscles. These types of diseases are caused by the degeneration of muscular tissue due to structural support protein abnormalities.
Metabolic myopathies. Metabolic myopathies are characterized by episodic muscle weakness that’s sometimes random but is often caused by exercise or muscle exertion. These myopathies are caused by defects in the genes that code for certain enzymes.
Acquired myopathies are myopathies that are acquired later in life. Examples of acquired myopathies include:
- Autoimmune/inflammatory myopathy. This type of myopathy causes issues with muscular function due to an autoimmune condition.
- Toxic myopathy. Toxic myopathy is myopathy caused by toxins — for example, alcohol — and certain medications.
- Endocrine myopathies. An endocrine myopathy is a myopathy caused by issues with the endocrine system, which controls hormone production. Endocrine myopathies can be caused by thyroid or adrenal diseases.
- Infectious myopathies. Infectious myopathies are myopathies caused by a viral, bacterial, parasitic, or fungal infection.
- Critical illness myopathy. Critical illness myopathy may develop while a person is in the intensive care unit. It’s thought to be caused by long periods of immobility. This type of myopathy affects the muscles you use to breathe.
Patients who have a blood relative with a genetic myopathy have an increased risk for developing the condition. Depending on how the myopathy is inherited, men can be at greater risk than women of developing the condition. Myopathies carried on the X chromosome affect more men than women, while those carried on chromosomes other than the sex chromosome affect both men and women equally.
Patients may be at increased risk of developing acquired myopathy if they have an autoimmune disorder, metabolic or endocrine disorder, are on certain drugs or are exposed to certain toxins.
There are several different types of genetic myopathies, most of which have similar symptoms. These include:
- Muscle weakness
- Motor delay
- Respiratory impairment
- Bulbar muscle dysfunction (malfunction of the muscles responsible for swallowing and speech)
Bulbar muscle dysfunctions can be especially apparent in congenital myopathies (those present from birth), and can result in severe impairments to swallowing and speech abilities. Congenital myopathies also are characterized by developmental motor delays and, at times, facial or skeletal abnormalities.
Acquired myopathies may have symptoms similar to those of genetic myopathies and also may include:
- Muscle weakness
- Muscle soreness (myalgias)
- Cramps
- Stiffness
- Muscle wasting around the shoulders and hips
The patient’s physician may use a variety of tests to determine the specific myopathy. These can include:
- A physical exam
- Muscle strength tests
- Electromyography (EMG)
- Ultrasound
- Magnetic resonance imaging (MRI)
- Genetic tests
- A muscle biopsy
The goal in determining the specific myopathy of each patient is to enable the development of a personalized treatment plan.
