Mastoiditis overview

# Overview
Mastoiditis is the infection of mastoid air cells in the process of temporal bone. It is mostly a complication of ear diseases such as acute otitis media and chronic otitis media, and it tends to occur in children. However after development of antibiotics, acute otitis media complications have decreased significantly.

# Historical perspective
Mastoiditis was first described by Hippocrates in the 5th century B.C.E. The first recorded surgical incision for treatment of medial ear infection was in the 16th century C.E., performed by French physician Ambroise Pare. Initial therapies for middle ear diseases were surgical, particularly mastoidectomy, which was first performed by French physician Jean-Louis Petit in the 17th century C.E. German physicians Hermann Schwartze, Anton von Troltsch, and Adam Politzer published the first journal dedicated to ear pathology and treatment in 1865. Antibiotic therapy for mastoiditis treatment emerged with the invention of mass production of penicillin in 1940 by Alexander Fleming, Howard Florey, and Ernst Chain. The pneumococcal conjugate vaccine (PCV) emerged in 2000, greatly reducing the incidence of otitis media and mastoiditis by vaccinating individuals against the causative pathogens.

# Classification
Mastoiditis may be classified into acute, subacute, and chronic forms, depending on the timing of presentation and duration.

# Pathophysiology
Mastoiditis is the infection in the cavities of mastoid process of temporal bone that occurs after otitis media. At birth, the mastoid consists of a single cavity, which is connected to the middle ear by a canal. As the child grows, the mastoid bone becomes pneumatized, resulting in a series of connected cavities, lined by a mucosa diverted from respiratory epithelium. There is a relationship between the middle ear, the eustachian tube, and the mastoid. This connection has a fundamental role in the pathogenesis of mastoiditis. In the setting of acute otitis media, the mucosa that lines the middle ear and mastoid air cells become inflamed. In most cases of acute otitis media, inflammation resolves, but it sometimes persists, leading to bacterial and fluid accumulation within the mastoid air cells. Gradually, as a result of pressure rising in the mastoid, air cell septae may be destroyed and mastoiditis could proceed to osteomyelitis. The mastoid is near vital organs in the head and neck and mastoid infection may cause serious complications. There is evidence of genetic predisposition to recurrent otitis media and therefore mastoiditis. The following genes have been identified as having potential pathogenic qualities for otitis media: CAPN14, GALNT14, BPIFA3, BPIFA1, BMP5, GALNT13, NELL1, and TGFB3.

# Causes
Mastoiditis results from middle ear infection. The most common bacteria that cause acute mastoiditis are Streptococcus pneumoniae, Streptococcus pyogenes, and Staphylococcus aureus. Staphylococci, Pseudomonas species, and polymicrobials are predominantly seen in non-acute mastoiditis. Pseudomonas aeruginosa may be found in children with acute mastoiditis as a consequence of recurrent acute otitis media and antibiotic use.

# Differentiating Mastoiditis from other Diseases
Mastoiditis must be differentiated from other diseases that cause postauricular inflammation or swelling such as lymphadenopathy, periauricular cellulitis, auricle perichondritis, mumps, and mastoid tumors. These diseases may be distinguished from mastoiditis via clinical findings and laboratory testing.

# Epidemiology and Demographics
Mastoiditis incidence is 1.26.1 per 100,000 inhabitants in developed countries. Serious progressions appear more frequently in young children. After using pneumococcal vaccination, the rate of acute otitis media and mastoiditis decreased dramatically. However, there is a concern about rising incidence, which is connected to inadequate antibiotic dosing in otitis media, choice of antibiotics, and increasing resistance of bacteria. Acute mastoiditis is most common among children under two years of age. Men and women are affected equally by mastoiditis. Otitis media and therefore mastoiditis are more prevalent in developing countries, specifically Sub-Saharan West Africa, Southeast Asia, and Oceania. Risk factors that may contribute to higher incidence in developing countries include exposure to HIV, malnutrition, a large proportion of children under 5 years in the population, and higher chance of water contamination.

# Risk Factors
The risk factors for mastoiditis are related to acute otitis media risk factors. Risk factors are allergy, upper respiratory tract infection, snoring, previous history of acute otitis media, passive smoking, mother smoking during pregnancy, and low social status. Exposure of infants to day-care centers is a controversial risk factor.

# Screening
There is insufficient evidence to recommend routine screening for mastoiditis.

# Natural History, Complications and Prognosis
If left untreated, mastoiditis will result in severe complications such as intracranial extension and permanent neurological deficits or death. The consequences of mastoiditis have been reduced after introduction of antimicrobial agents and adequate therapy of acute otitis media. However, if mastoiditis is not eradicated completely, it may give rise to severe complications. These complications are extracranial, such as osteomyelitis, labyrinthitis, facial nerve palsy, Bezold's abscess, hearing loss, subperiosteal abscess, or intracranial, such as epidural and subdural abscess, meningitis, temporal bone or brain abscess and venous sinus thrombosis. The prognosis of mastoiditis is good with treatment. Excellent outcomes can be expected for those who are managed without delay.

# Diagnosis

## History and Symptoms
History and symptoms of mastoiditis range from asymptomatic disease to symptomatic and progressive mastoiditis with serious life-threatening complications. History should be taken considering onset, duration, and progression of symptoms, allergies, previous history of acute otitis media, upper respiratory tract infection, associated symptoms (otalgia, fever, confusion), medications including antibiotic usage in acute otitis media, snoring, attendance to day care, history of trauma, co-morbid conditions like diabetes, immunodeficiency, and smoking. Common symptoms of mastoiditis are: ear pain, fever, feeling of "fullness" in the ear, recent episode of acute otitis media, discharge from the affected ear, partial hearing loss, irritability (in infants), headache, and lethargy/malaise. Neurological symptoms from chronic mastoiditis and otitis media with effusion include poor attention span, delayed speech development, clumsiness, and poor balance. Less common symptoms are gastrointestinal symptoms such as vomiting and diarrhea, meningismus, and torticollis

## Physical Examination
Mastoiditis physical examination includes posterior auricular signs such as postauricular swelling, erythema, tenderness, protrusion of pinna, and sagging external ear canal. Otoscopic examination of the middle ear shows erythema, bulging, cloudy appearance, and immobility of the tympanic membrane. Partial hearing loss from fluid buildup is indicative of otitis media, revealed by tympanometry. Acute mastoiditis patients are usually ill-appearing and usually present with low-grade fever, while complicated mastoiditis patients may present with severely ill appearance.

## Laboratory Findings
There are no diagnostic blood laboratory findings associated with mastoiditis. Some patients with mastoiditis may have elevated ESR, CRP, and white blood cells with a left shift. These laboratory findings are nonspecific and not helpful in making the diagnosis. It is very important to obtain clinical specimens for microbiology. Microbial results are crucial in the proper antimicrobial choice for treatment. There are multiple types of bacteria that may cause mastoiditis like Streptococcus species and Staphylococcus aureus, and there are rising concerns about antibiotic resistance in some microorganisms. The obtained fluid or pus should be sent for Gram stain, aerobic and anaerobic culture, and antimicrobial susceptibility testing. Specimens for mastoiditis treatment could be obtained via multiple sites such as middle ear via tympanocentesis or myringotomy, percutaneous aspiration from subperiosteal abscess, cerebrospinal fluid, or blood cultures.

## X-ray
There are no diagnostic X-ray findings associated with mastoiditis.

## CT scan
High Resolution CT scans of the temporal bone in mastoiditis patients are the preferred diagnostic tool and may reveal mastoiditis and its complications. CT findings in acute mastoiditis are: partial-to-complete opacification of mastoid air cells, erosion of mastoid air cell bony septum, mastoid cortex destruction and irregularity, periosteal thickening, periosteal disruption, and subperiosteal abscess. CT findings in subacute and chronic mastoiditis are: markers for inflammation, sclerosis, or opacification of mastoid process, tympanic membrane changes including thickening, retraction, tympanic membrane perforation, or calcification, ossicle erosion or other possible causes for hearing loss, determination of cholesteatoma, intratemporal complications such as petrositis, labyrinthitis, subperiosteal abscess, or labyrinthine fistula, intracranial complications such as brain abscess and meningitis, presence of fibrous tissue, tympanosclerosis, formation of new bone matter, ossicle erosion, and displacement and extension of cholesteatoma to sinuses.

## MRI
Both CT and MRI are used in the evaluation of mastoiditis and its complications. MRI in mastoiditis plays a role in the detection of cholesteatoma, also when intracranial and some intratemporal complications are suspected. Specifically, MRI has shown superiority in assessing the severity of intracranial involvement and abscess border visualization.

## Ultrasound
There are no ultrasound findings associated with mastoiditis.

## Other Imaging Findings
There are no other diagnostic findings for mastoiditis.

## Other Diagnostic Studies
Other mastoiditis imaging findings include otoscopic images of the tympanic membrane displaying middle ear effusion and infection. Also, tympanograms may be used for measuring pressure from fluid buildup in the middle ear.

# Treatment

## Medical Therapy
Medical treatment for acute and subacute mastoiditis without intracranial complications consists of intravenous antibiotics and myringotomy. Antibiotics for acute mastoiditis must cover the most common bacterial pathogens: Streptococcus pneumoniae, Streptococcus pyogenes, and Staphylococcus aureus (including methicillin-resistant S. aureus). If there is a history of recurrent acute otitis media or recent antibiotic usage, the intravenous antibiotic also should cover Pseudomonas aeruginosa. Bacteria commonly covered include Streptococcus pneumonia, Group A streptococcus, and Staphylococcus aureus. The empiric antibiotics are ampicillin-sulbactam or ampicillin; add vancomycin for severe infection with adjacent complications or suspicion of MRSA. For chronic mastoiditis, bacteria commonly covered are Pseudomonas aeruginosa, Staphylococcus aureus and anaerobes. Antibiotics include piperacillin-tazobactam or piperacillin, and ofloxacin otic solution; add vancomycin for severe infection with adjacent complications or suspicion of MRSA.

## Surgery
Different surgical procedures may be performed to treat mastoiditis. Myringotomy is surgical perforation of the tympanic membrane. It should be considered the primary treatment in all cases of infectious mastoiditis following otitis media, particularly when there is an unperforated tympanic membrane or inadequate drainage. Tympanocentesis should be performed in all mastoiditis patients to obtain middle ear fluid for culture and susceptibility testing. Myringotomy accompanied by the additional insertion of a tympanostomy tube is indicated in some cases, such as Eustachian tube dysfunction, suppurative complications requiring additional drainage, and when tympanic membrane must be repaired from Eustachian tube dysfunction. Definitive surgery is mastoidectomy, which is the surgical removal of the mastoid cortical bone and underlying air cells. Indications for mastoidectomy may include subperiosteal abscess such as postauricular fluctuance or mass, chronic suppurative otitis media or cholesteatoma, progression of postauricular swelling or fluctuance, fever, and other clinical findings or continuous drainage despite parenteral antimicrobial therapy and myringotomy.

## Primary Prevention
Preventing mastoiditis primarily involves preventing development of otitis media and nasopharyngitis. This is achieved by administration of the pneumococcal and influenza vaccines, frequently washing hands, and avoiding fluid transmission and respiratory droplets from nasopharyngitis patients. Preventing exposure to air pollution, as potential middle ear irritants such as secondhand smoke helps prevent otitis media, is also helpful in preventing mastoiditis. For infants, preventative measures include avoiding pacifiers, avoiding daycare enrollment, and breastfeeding until at least 6 months of age. A prophylactic regimen of antibiotics can prevent otitis media in at-risk infants and children.

## Secondary Prevention
For mastoiditis following chronic or recurrent otitis media, preventing recurrence of the disease involves surgery, assuming the manifestation is not self-limited. Myringotomy with tympanostomy tube and mastoidectomy is the most common surgical preventative measure.