Otitis media overview

# Overview
Otitis media is inflammation of the middle ear. Otitis media was first described by Hippocrates in the 5th century B.C.E. Initial therapies for otitis media were surgical, particularly mastoidectomy, which was first performed by French physician Jean-Louis Petit in the 17th century C.E. Antibiotic therapy for otitis media treatment emerged with the invention of mass production of penicillin in 1940 by Alexander Fleming, Howard Florey, and Ernst Chain. The pathogenesis of otitis media is directly connected to the pathogen responsible for nasopharyngitis. This includes infectious causes, such as viral upper respiratory infection, as well as bacterial infection from Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Staphylococcus aureus. Mucus in the middle ear causes congestion that results in dysfunction of the eustachian tube. Pressure regulation in the inner ear is altered, causing effusion of fluid into the tympanic cavity containing the pathogen of nasopharyngitis. Otitis media results from the inflammatory response to the infection. Otitis media is transmitted through respiratory droplets through saliva or mucus, as well as direct physical contact with a contaminated individual or physical surface. There is evidence of genetic predisposition to otitis media, with statistically significant evidence that it has high heritability. Otitis media can be classified into acute, effusive, and chronic suppurative forms. Their clinical presentations will vary based on the different symptoms. The most common symptoms of all classifications of otitis media are ear pain and feelings of "fullness" in the ear due to fluid buildup in the eustachian tube. These are usually accompanied by ear fluid discharge, as well as partial loss of hearing. Common cold symptoms, including cough, nasal discharge, and fever, usually accompany acute otitis media. Symptoms of chronic otitis media with effusion usually include neurological conditions, such as irritability, poor physical coordination, and delayed speech development and poor attention span in infants and young children. Upon physical examination, the most indicative signs of otitis media by otoscopic examination of the middle ear include erythema, bulging, cloud appearance, and immobility of the tympanic membrane. The presence of effusion is also indicative of otitis media. The mainstay of therapy for acute otitis media (AOM) is antimicrobial therapy. Ear pain is managed with acetaminophen, ibuprofen, or narcotic analgesics with codeine. Surgery to treat otitis media is primarily myringotomy with or without insertion of a tympanostomy tube. It is indicated for recurrent cases of acute otitis media and chronic suppurative otitis media when non-surgical treatment therapies do not relieve symptoms. Preventing otitis media primarily involves preventing developing nasopharyngitis. Preventing exposure to air pollution as potential middle ear irritants, such as secondhand smoke, contributes to preventing otitis media. For infants, preventative measures include avoiding pacifiers, avoiding daycare enrollment, and breastfeeding until at least 6 months of age.  Otitis media must be differentiated from other diseases that cause ear pain or ear itchiness, hearing loss, middle ear discharge, tympanic effusion, and dizziness. The most potent risk factor for otitis media is age, specifically being younger than 5 years old. Other common risk factors include exposure to smoke and air pollution, malnutrition, lack of breastfeeding, enrollment in daycare, allergies or recurrent upper respiratory infections, living in cold climates or climates subject to sudden changes, being a male younger than 20 months old, and being of Caucasian, Greenlandic, Southeast Asian, or Sub-Saharan West African descent. The incidence for otitis media is usually high: on an annual basis, approximately 10% of the world's population will develop acute otitis media (AOM). Children under 5 years old are the primary demographic for otitis media: 51% of the global incidence of AOM and 22.6% of the global incidence of CSOM are under 5 years old. The prognosis of otitis media is usually good with or without treatment, but varies based on the classification. Acute otitis media is self-limited and usually resolves itself within 14 days, and otitis media with effusion will usually resolve itself within 3-6 months. Chronic suppurative otitis media will usually require surgical or antibiotic intervention to alleviate symptoms and resolve the disease. Complications of otitis media result from the spread of causative infection, as well as damage to the tympanic membrane due to fluid buildup and pressure changes. Presence of complications can increase the morbidity in otitis media patients and decrease the prognosis.

# Historical Perspective
Otitis media 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 otitis media 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 otitis media 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 by vaccinating individuals against the causative pathogens.

# Pathophysiology
The pathogenesis of otitis media is directly connected to the pathogen responsible for nasopharyngitis. This includes infectious causes, such as viral upper respiratory infection, as well as bacterial infection from Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Staphylococcus aureus. Mucus in the middle ear causes congestion that results in dysfunction of the eustachian tube. Pressure regulation in the inner ear is altered, causing effusion of fluid into the tympanic cavity containing the pathogen of nasopharyngitis. Otitis media results from the inflammatory response to the infection. Otitis media is transmitted through respiratory droplets through saliva or mucus, as well as direct physical contact with a contaminated individual or physical surface. Otitis media is usually associated with other upper respiratory conditions caused by the nasopharynx pathogen, as well as allergic conditions such as allergic rhinitis. There is evidence of genetic predisposition to otitis media, with statistically significant evidence that it has high heritability. The following genes have been identified as having having potential pathogenic qualities for otitis media: CAPN14, GALNT14, BPIFA3, BPIFA1, BMP5, GALNT13, NELL1, TGFB3. Up-regulation of the genes correlated to otitis media pathogenesis contribute to individual susecptibility to the disease.

# Causes
Otitis media is caused eustachian tube dysfunction due to varying factors. Infection-based otitis media is usually caused by the pathogen causing nasopharyngitis, including bacterial and viral causes of upper respiratory tract infections. Other factors include allergies, airborne irritants, and sources of injury and rupture to the tympanic membrane. This includes physical injury, extremely loud noise, and sudden changes in atmospheric pressure.

# Classification
Otitis media can be classified into acute, effusive, and chronic suppurative forms. Their clinical presentations will vary based on the different symptoms. The treatment necessity will also vary based on classification.

# Differentiating Otitis Media from Other Diseases
Otitis media must be differentiated from other diseases that cause ear pain or ear itchiness, hearing loss, middle ear discharge,tympanic effusion, and dizziness. This includes otitis externa, myringitis, sinusitis, and Meniere's disease.

# Epidemiology and Demographics
The incidence for otitis media is usually high: on an annual basis, approximately 10% of the world's population will develop acute otitis media (AOM). Chronic suppurative otitis media (CSOM) has a smaller incidence and will affect approximately 0.45% of the world's population. Children under 5 years old are the primary demographic for otitis media: 51% of the global incidence of AOM and 22.6% of the global incidence of CSOM  are under 5 years old. People of Caucasian, African, and Greenlandic descent are most prone to otitis media. For children under 20 months old, males are more likely to develop otitis media due to differing rates of respiratory maturity. Otitis media is most prevalent in developing countries, specifically Sub-Saharan West Africa, Southeast Asia, and Oceania. Risk factors that heighten otitis media presence in developing countries include greater cases of malnutrition, more exposure to HIV, higher chance of water contamination, and larger proportion of the populations being children under 5 years old. Fatal cases of otitis media are very rare, with the case fatality rate being approximately .003% of all otitis media cases.

# Risk Factors
The most potent risk factor for otitis media is age, specifically being younger than 5 years old. Other common risk factors include exposure to smoke and air pollution, malnutrition, lack of breastfeeding, enrollment in daycare, allergies or recurrent upper respiratory infections, living in cold climates or climates subject to sudden changes, being a male younger than 20 months old, and being of Caucasian, Greenlandic, Southeast Asian, or Sub-Saharan West African descent.

# Natural History, Complications, and Prognosis
The prognosis of otitis media is usually good with or without treatment, but varies based on the classification. Acute otitis media is self-limited and usually resolves itself within 14 days, and otitis media with effusion will usually resolve itself within 3-6 months. Chronic suppurative otitis media will usually require surgical or antibiotic intervention to alleviate symptoms and resolve the disease. Acute otitis media rapidly follows the onset of nasopharyngitis; otitis media with effusion and chronic suppurative otitis media may develop following the resolution of acute otitis media symptoms and have a longer symptomatic duration. Complications of otitis media result from the spread of causative infection, as well as damage to the tympanic membrane due to fluid buildup and pressure changes. Presence of complications can increase the morbidity in otitis media patients and worsen the prognosis.

# Diagnosis

## History and Symptoms
The most common symptoms of all classifications of otitis media are ear pain and feelings of "fullness" in the ear due to fluid buildup in the eustachian tube. These are usually accompanied by ear fluid discharge, as well as partial loss of hearing. Common cold symptoms, including cough, nasal discharge, and fever, usually accompany acute otitis media. Symptoms of chronic otitis media with effusion usually include neurological conditions, such as irritability, poor physical coordination, and delayed speech development and poor attention span in infants and young children. History of smoking, allergies, having an occupation with exposure to air pollution, attending day care, and having a family history of ear infections can be indicative of and should be considered when diagnosing otitis media.

## Physical Examination
The most indicative signs of otitis media are revealed through otoscopic examination of the middle ear and include erythema, bulging, cloud appearance, and immobility of the tympanic membrane. The presence of effusion is also indicative of otitis media. Partial hearing loss from fluid buildup is indicative of otitis media, revealed by tympanometry. Acute otitis media patients are usually ill-appearing and usually present with low-grade fever. Otitis media with effusion patients are usually well-appearing since the condition is not usually associated with common cold symptoms.

## Laboratory Findings
There are no laboratory findings specifically associated with otitis media. General markers for inflammation may be present.

## CT or MRI Imaging
Imaging in otitis media patients will reveal opacification of the middle ear, for acute, chronic, and otitis media with effusion. High Resolution CT scans of the temporal bone in acute otitis media patients may reveal complications, including otomastoiditis. MRI is used for patients with suspected intracranial complications, such as brain abscess. sinus thrombosis, and meningitis. For otitis media with effusion patients, contrast-enhanced MRI or CT scan imaging may reveal complete and homogenous middle ear and mastoid cavity opacification. Primary imaging findings for chronic otitis media include complications associated with and without cholesteatoma.

## Other Imaging Findings
Other otitis media imaging findings include otoscopic images of the tympanic membrane displaying indications of otitis media, as well as tympanograms indicating otitis media with effusion by measuring pressure from fluid buildup in the middle ear.

# Treatment

## Medical Therapy
The mainstay of therapy for acute otitis media (AOM) is antimicrobial therapy. High-dose Amoxicillin is the drug of choice for initial antibiotic therapy; high-dose Amoxicillin-Clavulanate or intramuscular Ceftriaxone should be reserved for patients who fail to respond to first-line treatment within 48 to 72 hours. Antimicrobial agents covering common bacterial pathogens (e.g., Streptococcus pneumoniae, Moraxella catarrhalis, and non-typeable Haemophilus influenzae) have been used with success in selected patients to accelerate the recovery and lower the risk of tympanic membrane perforations and contralateral AOM episodes. The optimal duration of antibiotics remains uncertain: a 10-day course of antibiotic therapy is recommended for children younger than 2 years and children with severe symptoms. In the absence of severe symptoms, a 7- or 5-day course is advisable for children 2 to 5 years of age or children 6 years and older, respectively. Current guidelines recommend observation for children age 6 to 24 months with unilateral AOM without otorrhea or children older than 2 years with unilateral or bilateral AOM without otorrhea. Otalgia is generally managed with Acetaminophen, Ibuprofen, or narcotic analgesics with Codeine.

## Surgery
Surgery to treat otitis media is primarily myringotomy with or without insertion of a tympanostomy tube. It consists of creating an incision inside the tympanic membrane to relieve pressure by draining effusive fluid or suppuration. It is indicated for recurrent cases of acute otitis media and chronic suppurative otitis media when non-surgical treatment therapies do not relieve symptoms. Insertion of a tympanostomy tube is indicated for otitis media cases of which there is eustachian tube dysfunction causing necessary tympanic membrane reparation, as well as for suppurative complications requiring additional draining. Otorrhea is a possible complication of myringotomy performed with a tympanostomy tube inserted.

## Prevention
Preventing otitis media primarily involves preventing developing nasopharyngitis. This is achieved by 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, contributes to preventing otitis media. 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. For otitis media that is chronic or recurrent, preventing recurrence of the disease involves surgery, assuming the manifestation is not self-limited. Myringotomy with tympanostomy tube is the most common surgical preventative measure.