Mastoiditis

What is Mastoiditis?

Mastoiditis is an inflammation of a part of the skull bone called the mastoid air cells. These are small, hollow areas in the bone that are connected to the middle ear. Children are more prone to middle ear infections, which makes them more likely to get mastoiditis. In most cases, mastoiditis happens because of a severe middle ear infection. But, it can also occur because of an infection of the mastoid air cells by themselves or due to persistent middle ear infections.

Thanks to antibiotics, mastoiditis is quite unlikely to occur, and it’s even less likely to lead to serious consequences today. However, if it’s not treated, mastoiditis can lead to serious, life-threatening conditions such as meningitis, brain abscesses, or a blood clot in the veins of the brain. Despite advances in diagnostics, antibiotics, and microscopic surgeries, around 10% of children who experience complications from mastoiditis tragically do not survive.

What Causes Mastoiditis?

Mastoiditis, an infection in the mastoid bone located behind the ear, can be classified into three types based on the way the infection occurs:

* Initial Stage Mastoiditis: Here, only the small, air-filled spaces in the mastoid bone get infected, and it doesn’t spread to the middle part of your ear.

* Acute Coalescent Mastoiditis (most commonly seen): In this condition, the lining of these air spaces becomes inflamed and the infection starts to eat away at the bone partitions within these spaces. This could potentially lead to the infection spreading to adjacent areas and form a pus-filled pocket known as an abscess.

* Subacute Mastoiditis: If infections in the middle ear are frequent or persist due to improper use of antibiotics, this can lead to continued infection of both the middle ear and the mastoid air spaces. This can result in similar erosion of the bone partitions within the mastoid.

Risk Factors and Frequency for Mastoiditis

Mastoiditis can happen to anyone, but children under two years old are the ones mostly affected, especially those around 12 months old. Before we had antibiotics, around 20% of ear infections called acute otitis media would turn into mastoiditis which could cause serious complications in the brain.

However, with the introduction of antibiotics, mastoidectomy (a surgical procedure to remove the mastoid), and a specific vaccine (PCV-7), the number of mastoiditis cases has decreased significantly. To give an idea of this change, consider these numbers:

• Prior to antibiotics, 5-10% of children with acute otitis media would develop mastoiditis, with 2 deaths per 100,000 people.
• After the introduction of antibiotics and PCV-7, now only 0.002% of children with the same condition develop mastoiditis, and the death rate has fallen to less than 0.01 per 100,000 people.

Signs and Symptoms of Mastoiditis

Acute mastoiditis is a condition often spotted in children under two years of age or in adults. Typical symptoms for children include being easily irritated or moody, feeling tired, having a fever, pulling at their ears, and experiencing ear pain. For adults, they might report intense ear pain, fever, and headaches.

When a doctor examines the patient, they might notice redness, tenderness, warmth, and swelling behind the ear, along with the ear sticking out more than usual. An ear examination could show a bulge in the back upper wall of the ear canal, a swelled up and possibly pus-filled eardrum, which might even be ruptured and leaking pus.

• Children: irritability, fatigue, fever, ear pulling, ear pain.
• Adults: severe ear pain, fever, headache.
• Physical examination: redness, tenderness, warmth, swelling behind the ear, protruding ear.
• Ear examination: bulging back upper wall of the ear canal, swollen and pus-filled eardrum, possible rupture and pus leakage.

However, it’s important to keep in mind that if the eardrum looks normal, this doesn’t always rule out acute mastoiditis. While it’s common for patients to have a history of ear infections, it’s not a prerequisite for diagnosing mastoiditis. Sometimes the condition can occur quickly at the same time as an acute ear infection.

Testing for Mastoiditis

Mastoiditis is mostly diagnosed by your symptoms and physical exam. But when doctors are uncertain about the diagnosis or suspect there may be complications, they may conduct lab tests and medical imaging.

The lab tests often include a complete blood count (CBC) with differential, Erythrocyte Sedimentation Rate (ESR), and C-Reactive Protein (CRP). The CBC test measures the number of different types of cells in your blood. The ESR test and CRP tests are used to check for inflammation in your body. In most cases of mastoiditis, these tests will show an increased number of white blood cells and higher markers of inflammation.

For medical imaging, doctors usually use Computerized Tomography (CT) scans. This type of imaging provides detailed pictures of the inside of your body and can help doctors see if the infection has spread or caused other complications.

A CT scan for mastoiditis may show:

– Fluid buildup or thickening of the mucus in the middle ear and mastoid, which is a part of your skull behind your ear.
– Loss of the sharp outlines of the air-filled spaces in the mastoid, called mastoid air cells, showing they are filled with fluid or pus.
– Damage to the bumpy outer surface of the mastoid, called the mastoid cortex.

Thickening, disruption, or an abscess (pocket of pus) under the thin layer of tissue that lines the outside of your bones, known as the periosteum.

Treatment Options for Mastoiditis

Mastoiditis is a bacterial infection that affects a section of the skull called the mastoid bone, located behind the ear. It’s serious and can cause complications if not treated promptly. While antibiotics are the main treatment for mastoiditis, relying on them alone can lead to complications in 8.5% of cases. In more severe cases, other treatments such as myringotomy (an incision into the eardrum to relieve pressure), tympanostomy tube placement (the insertion of a small tube into the eardrum to help fluid drain), and mastoidectomy (surgery to remove part of the mastoid bone) may be necessary. Most people with acute mastoiditis are admitted to the hospital for treatment.

Patients with no significant prior illnesses and only minor physical symptoms have been successfully treated outside the hospital with daily intravenous (IV) antibiotics, resulting in a low rate of complications. However, the case becomes more complex if the patient develops symptoms such as a large lesion behind the ear, bone erosion seen on imaging studies, high fevers, or neurological signs. In these cases, in-hospital treatment with IV antibiotics, high-dose IV steroids, and myringotomy with tympanostomy tube placement may be needed.

Regular check-ups are necessary, as a patient’s condition can worsen rapidly. If there’s no improvement in the symptoms of mastoiditis within 48 hours, a mastoidectomy may be required. Vancomycin, an antibiotic given through an IV line, is commonly used to treat the bacterial pathogens frequently responsible for mastoiditis, including Streptococcus pneumoniae. Other bacteria that can cause this infection include Group A beta-hemolytic streptococci, Staphylococcus aureus, Streptococcus pyogenes, and Haemophilus influenza.

For patients with a chronic history of ear infections, an additional antibiotic that’s effective against Pseudomonas bacteria may be combined with vancomycin for treatment. Streptococcus pyogenes has been linked to the highest rate of complications at presentation in a multicenter study, occurring in almost half of the cases. Staphylococcus aureus was associated with the highest rate of complications during hospitalization.

What else can Mastoiditis be?

It’s really important for your doctor to get a detailed background of your health and examine you thoroughly. This is because there are conditions that can appear similar to acute mastoiditis, which can be overlooked and lead to a delay in the right treatment if not considered. These include skin infections (cellulitis), ear canal infections (otitis externa), swollen lymph nodes (lymphadenopathy), injury (trauma), or even a growth or tumor.

Several cases have reported that tumors or cancers, such as rhabdomyosarcoma, Ewing sarcoma, and myofibroblastic tumor, have been mistaken for mastoiditis. These types of cases can be more complex because they tend to affect both sides, involve the nerves in the head (cranial nerves) and the person may not have a fever.

It’s important to keep these possibilities in mind because both mastoiditis and tumors are common in children.

What to expect with Mastoiditis

Most patients with uncomplicated acute mastoiditis, which is an infection in a part of the ear called the mastoid bone, successfully recover with simple treatments. These treatments typically involve the use of antibiotics, steroids, and a minor procedure called myringotomy, which involves making a small hole in the eardrum to relieve pressure and drain fluid. These patients usually do not need a more invasive procedure called a mastoidectomy, which involves removing part or all of the mastoid bone.

Despite this, there’s a lack of research comparing the effectiveness of simple treatments versus more invasive treatments for acute mastoiditis. Therefore, it’s very important to closely keep an eye on patients undergoing treatment for this condition, especially during the first 48 hours of the treatment.

If a patient’s condition does not improve or, worse, deteriorates after the initial admission, a mastoidectomy may then be recommended.

Possible Complications When Diagnosed with Mastoiditis

If acute mastoiditis, a type of ear infection, isn’t addressed quickly, it can lead to severe complications. Due to its location, the infection can spread either towards the brain or outward. There are a few complications outside the skull that may occur. These complications include:

• A subperiosteal abscess, which is an abscess forming on the outer layer of the skull near the site of the infection.
• Facial nerve palsy, which is facial weakness caused by the infection pressing on a facial nerve.
• Labyrinthitis, an inner ear problem that can cause ringing in the ears due to the infection spreading within the middle ear cavity.
• Petrous apicitis, an infection of other parts of the skull, typically causing ear discharge, behind-the-eye pain, double vision, and other issues related to nerve damage.
• A Bezold abscess, which is an abscess located in the protective covering of a neck muscle.

On the other hand, around 6 to 23% of acute mastoiditis cases result in complications inside the skull. Symptoms that suggest these complications include seizures, neck stiffness, headaches, and changes in mental state. The complications that may occur inside the skull include:

• Abscesses in the temporal lobe or cerebellum.
• Abscesses in the protective layers surrounding the brain and spinal cord.
• Clotting in the brain’s veins, the least common of all intracranial complications.

Preventing Mastoiditis

The best way to prevent mastoiditis, an infection of a bone in the skull, is by getting vaccinated. People who are not vaccinated are more likely to catch a germ called pneumococcus. This germ often causes an ear infection called otitis media, which can further develop into mastoiditis. Getting early treatment for otitis media can help stop it from turning into mastoiditis.

There are also other factors that increase the risk of getting mastoiditis, but unfortunately, these cannot be changed. These include being younger than 2 years old, having a weak immune system, having repeated bouts of otitis media, or having a certain physical condition of the mastoid bone.