Our son had eleven middle ear infections treated with antibiotics by the time he was two. When we were finally referred to the ear specialist, we discovered that complications had set in—hearing loss, speech and language delay, and worst of all, a growth in the middle ear that is called cholesteatoma.
Mastoiditis
Mastoiditis is an infection of the mastoid bone, a hollow, air-containing bone like the nasal sinuses. The mastoid is connected to the middle ear and located just behind the outer and middle ear. Middle ear infections easily spread to the mastoid bone, but usually do not cause clinical problems. The treatment of acute otitis media (see chapter 4) is usually sufficient to also treat mastoiditis if it is present.
However, if acute otitis media does not resolve, it can lead to more advanced clinical mastoiditis. Before antibiotics, mastoiditis was the most common cause of hospitalization of children. About three thousand new cases of mastoiditis are diagnosed each year in the United States, an incidence of about one per year for every 100,000 people.
Symptoms and Signs
Mastoiditis may occur in children and adults who have no history of ear problems. Ear drainage for more than one week is a sign that mastoiditis has developed. It is often accompanied by fever and pain behind the ear in children, but infants may show non-specific signs such as poor feeding, restlessness, and irritability.
Evaluation
Your child’s doctor will look in his or her ears and usually find that the eardrum has ruptured and pus is actively draining from the ear canal. The skin of the ear canal may be sagging. The skin behind the ear may be swollen or red and the pinna may be over-protruding from the head. A blood test will show a high white blood cell count, typical of serious infections. Referral to a specialist is quickly made.
The ENT may order a CT scan to determine if the infection has caused destruction of thin partitions of bone in the air-containing mastoid. CT will also identify advanced complications, such as abscess formation and meningitis. If bone resorption (breakdown of the tissue in bones with subsequent release of minerals into the bloodstream) is seen, the term coalescent mastoiditis is used and surgery to drain the infection and remove infected bone should be performed within twenty-four hours.
Bacterial Organisms
Mastoiditis is most often caused by Streptococcus pneumoniae or Streptococcus pyogenes. Other commonly reported causative organisms include Staphylococcus aureus, Haemophilis influenzae, coagulase negative Staphylococcus, and Pseudomonas aeruginosa.
Treatment
Medical and surgical treatment depends on the extent of disease and the condition of the patient. In general, hospitalization is required and intravenous antibiotics are used. If the eardrum is bulging, then the perforation, if present, is not large enough to drain the infection, and a large opening in the eardrum is made. This allows irrigation of the middle ear with antibiotic solution and suction removal of infected material.
If the CT scan shows destruction of the mastoid bony dividing walls, called coalescent mastoiditis, then a mastoidectomy is required. After surgery, a drain is often used to allow the pus to exit through the mastoid incision, avoiding further destruction of the eardrum. Combination suction/irrigation drains, which continuously bathe the mastoid cavity with antibiotic solution, are also used.
Cholesteatoma
Another common complication of chronic otitis media is the development of cholesteatoma. This is a benign cyst-like growth that tends to stay infected. In the process of constantly enlarging, this cyst can destroy bone it comes into contact with.
Cholesteatomas form in chronically infected ears when negative pressure in the middle ear space or ingrowth of the eardrum causes a gradual retraction of the eardrum inwards, forming a pocket. The pocket is lined by skin of the eardrum and, like all skin, it sheds layers every day. The layers gradually build up, enlarging the pocket. This incites a local inflammatory reaction that can erode into neighboring structures, most commonly the hearing bones, leading to a conductive hearing loss. Rarely the cholesteatoma can erode into the inner ear, which can lead to a total hearing loss. It can also cause facial paralysis/weakness and meningitis.
Cholesteatomas are usually infected since the shedding skin serves as an excellent media for bacterial growth. In addition, the bacteria frequently form a biofilm that makes medical eradication of the infection difficult. Bacteria in a cholesteatoma tend to accelerate its growth.
Infrequently, infants and young children are noted to have a white growth behind the eardrum, a cholesteatoma that they were born with. Congenital cholesteatomas are not related to ear infections. When children with these growths are referred early, the cholesteatomas can be removed simply by operating under the eardrum. However, if there is a delay in diagnosis, the congenital cholesteatoma tends to enlarge and spread and may lead to a lifetime of difficulty.
Figure 20.1
Cholesteatoma is a benign growth usually associated with chronic infection. As it enlarges, it destroys adjacent tissue such as the eardrum and bones of hearing.
Symptoms
The most common symptom of cholesteatoma is ear drainage that only temporarily responds to treatment with antibiotic drops. Conductive hearing loss is the other common symptom associated with cholesteatoma. This may be caused by infected fluid or damage to the middle ear bones. Typically, bony erosion involves the incus and stapes while the malleus is less frequently damaged.
Treatment Options
Tympanomastoidectomy
Cholesteatoma must be surgically removed, preferably before bone destruction occurs. Tympanomastoidectomy is an operation that takes two to three hours (or more) to perform. It is usually done on an outpatient basis, but requires general anesthesia. The skin and remainder of the eardrum are lifted to expose the cholesteatoma in the middle ear and an incision is made in the crease behind the ear. Through that incision, the bone overlying the mastoid cavity is removed to expose the cholesteatoma within the cavity. The extent of the mastoidectomy is dependent on the extent of disease and the patient’s anatomy.
Intact Canal Wall Mastoidectomy
This procedure leaves the basic structure of the middle ear and mastoid cavity intact. It begins by lifting the remnants of the eardrum and opening the mastoid cavity. The eardrum is reconstructed. There are advantages if the entire cholesteatoma can be removed this way (it usually results in better hearing, and the patient can swim and shower without concern after a healing period). However, because early recurrence of cholesteatoma cannot be detected, a “second-look” procedure is required six to twelve months after the first operation to be certain that there is no recurrence. Erosion of the hearing bones is common with cholesteatoma and frequently requires reconstruction by placement of a prosthesis that reconnects the eardrum with the inner ear (see chapter 18).
Canal Wall Down (Modified Radical) Mastoidectomy
When disease is too extensive or when there is more than one recurrence of cholesteatoma with intact canal wall surgery, the ear canal and mastoid cavity are joined and exteriorized through an enlarged ear canal opening. The eardrum is reconstructed. Modified radical mastoidectomy provides greater surgical access and the ability to see recurrence of cholesteatoma in the mastoid cavity. It does not allow improved visualization of recurrence in the middle ear because the eardrum is reconstructed. Benefits are better visualization and putatively fewer recurrences. Its shortcomings are the requirement for microscopic cleaning of the cavity every six to twelve months throughout life and avoidance of water in the cavity in most instances.
Radical Mastoidectomy
In radical mastoidectomy, as in the canal wall down mastoidectomy technique, the mastoid cavity is exteriorized. However, in this procedure the eardrum is not reconstructed. A very large, sometimes disfiguring, opening from the cavity to the outside is required. This results in worse hearing and often more infections. Radical mastoidectomy is usually reserved for use after failure of more conservative procedures.
Complications
Despite optimal management, cholesteatoma recurrence rates range from 5 to 10 percent in adults and as high as 20 percent in young children. Lifelong surveillance for the disease is mandatory, usually on a yearly basis. As mentioned earlier, patients undergoing a canal wall down procedure will require routine visits to their ear surgeon to clean their mastoid cavity, usually every six to twelve months.
Facial nerve weakness is a rare complication of ear surgery. If facial paralysis or weakness occurs prior to surgery, it is likely that the cholesteatoma has surrounded the facial nerve. Nonetheless, the nerve can most often be preserved. If it is stretched during removal, a temporary weakness may result. If it is cut, the weakness will be permanent and early facial nerve grafting is necessary.
If the cholesteatoma invades the inner ear, removing it may result in nerve deafness and vertigo. Nonetheless, in most cases it must be removed or it will continue to invade, cause deafness, and may lead to meningitis.