Ear injury and infections are not uncommon but most of these time these conditiosn involves the outer and middle ear. This is particularly common in children. Most of the time we do not think of it as a serious condition but when the problem extends deeper into the inner ear then the consequences can be severe.
What is otitis interna?
Otitis interna is inflammation of the inner ear often due to an infection. It should not be confused with otitis externa (external ear infection) and otitis media (middle ear infection). Otitis interna is also referred to as labyrinthitis named after the bony labyrinth of the inner ear. Since the organs of hearing and balance are located within the inner ear, a person may experience symptoms like hearing loss, poor balance and dizziness as a result of otitis interna.
Overall otitis interna is not as common as otitis media or otitis externa. However, when it does occur it is often taken more seriously due to teh proximity to the brain. It requires prompt medical attention especially when it arises as a result of an infection as delaying treatment could lead to serious outcomes and even death depending on the underlying cause. Otitis interna can affect any person of any age and may arise as a complication of a middle ear infection (otitis media).
Anatomy of the Inner Ear
It is important to understand the anatomy of the inner ear to further understand the effects of otitis interna. There are four main parts of the inner ear:
- Semicircular canals
The labyrinth is the bony canal that lies within the skull (temporal bones). It has an inner membrane and is filled with fluid known perilymph. The semicircular canals and the vestibule are collectively referred to as the vestibule system. It is responsible for the sense of balance. The other important organ is the cochlea. Movements of the ossicles in the middle ear transmit sound waves to he perilymph which in turns stimulates the cochlea. This is converted to nerve signals and relayed to the brain. The cochlea is responsible for hearing.
Signs and Symptoms
When otitis externa arises as a consequence of other infections there may be early symptoms like an ear discharge. It is important to note that these symptoms are not usually part of otitis externa. Given the orgns of the inner ear, the following symptoms are usually present in otitis externa:
- Vertigo – sensation of the surroundings spinning
- Dizziness – lightheadedness
- Nystagmus – rapid shaking of the eyes
- Hearing loss – usually partial and one-sided
- Tinnitus – ringing noise in the ears
- Otalgia – pain in the ears
Other symptoms that may also be present include nausea, vomiting, fever, neck pain and neck stiffness. As with any condition, otitis interna may not always present with all these symptoms and sometimes non-specific symptoms like dizziness may be the only symptoms present.
Causes of Otitis Interna
There are a number of different causes of otitis interna. Inflammation can be classified as infectious or non-infectious. Infections are among the more common of these causative factors.
Trauma to the head can lead to internal ear injury depending on the severity of the injury. Similarly a severe injuy to the ear can lead to inner ear trauma and inflammation. Less commonly surgery may cause inner ear injury. Although high pressure can injure the outer ear and even the middle ear to some extent, the inner ear is usually not affected.
Viral and bacterial infections can also cause otitis interna. A number of different viruses can cause otitis interna ranging from the flu virus to other upper respiratory viruses, as well as common childhood viral infections such as mumps and measles. Shingles, which is a reactivation of the chickenpox virus, can also affect the inner ear. In some of these viral infections there can be permanent hearing loss but it depends on the virus in question.
Any pathogenic bacteria that can reach the tissue of the inner ear may cause otitis interna. It is rare for these bacteria to reach the inner ear from the outer environment without first causing middle and outer ear infections since the inner ear lies so deep. Instead the bacteria may reach the inner ear from the brain and meninges in conditions like bacterial encephalitis and meningitis. Sometimes the toxins of these bacteria can reach the inner ear tissue and cause inflammation.
Autoimmune conditions cause inflammation when the immune system attacks the body’s own tissue. This may occur for a number of different reasons and is usually chronic in nature. Another type of immune dysfunction is an allergy. Here the tissue becomes inflamed when it comes into contact with harmless substances to which teh body has a sensitivity.
A number of substances can cause inner ear inflammation. These substances are able to reach the inner ear tissue through the bloodstream. It can range from medication and alcohol to illicit substances and toxins. Some of these substances are specifically toxic to inner ear tissue and therefore referred to as ototoxic. Depending on the substance in question, the dosage and level fo toxins in the bloodstream can determine the degree of toxicity to the inner ear tissue.
Treatment of Otitis Interna
The choice of treatment of otitis interna depends on the underlying causes. Sometimes treatment specifically for otitis interna is not necessary, as is the case with many viral infections which resolve spontaneously. Supportive measures may be all that is needed in this case and it involves bed rest, fluid intake and proper nutrition. However, there are times where medication is necessary.
Anti-inflammatory drugs and corticosteroids may be used to indiscriminately reduce inflammation irrespective of the cause. Antibiotics are used for bacterial infections while antivirals may sometimes ne necessary for viral infections. With substances, the approach to treatment is largely supportive management until the toxins are flushed out of the system. However, substances to neutralize it may sometimes be necesary.
Otitis interna is a pontentially serious condition and needs to be diagnosed, treated and managed by a medical professional.