出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2016/01/09 02:20:28」(JST)
Otitis media | |
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A bulging tympanic membrane which is typical in a case of acute otitis media
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Classification and external resources | |
Specialty | Otorhinolaryngology |
ICD-10 | H65-H67 |
ICD-9-CM | 017.40, 055.2, 381.0, 381.1, 381.2, 381.3, 381.4, 382 |
DiseasesDB |
29620 serous, |
MedlinePlus | 000638 acute, 007010 with effusion, 000619 chronic |
eMedicine | emerg/351 ent/426 complications, ent/209 with effusion, ent/212 Medical treat., ent/211 Surgical treat. ped/1689 |
MeSH | D010033 |
Otitis media is a group of inflammatory diseases of the middle ear.[1] The two main types are acute otitis media (AOM) and otitis media with effusion (OME).[2] AOM is an infection of abrupt onset that usually presents with ear pain. In young children this may result in pulling at the ear, increased crying, and poor sleep. Decreased eating and a fever may also be present. OME is typically not associated with symptoms.[3] Occasionally a feeling of fullness is described. It is defined as the presence of non-infectious fluid in the middle ear for more than three months. Chronic suppurative otitis media (CSOM) is middle ear inflammation of greater than two weeks that results in episodes of discharge from the ear. It may be a complication of acute otitis media. Pain is rarely present.[4] All three may be associated with hearing loss.[1][2] The hearing loss in OME, due to its chronic nature, may affect a child's ability to learn.[4]
The cause of AOM is related to childhood anatomy and immune function. Either bacteria or viruses may be involved. Risk factors include exposure to smoke, use of pacifiers, and attending daycare. It occurs more commonly in those who are Native American or who have Down syndrome.[4] OME frequently occurs following AOM and may be related to viral upper respiratory infections, irritants such as smoke, or allergies.[2][4] Looking at the eardrum is important for making the correct diagnosis.[5] Signs of AOM include bulging or a lack of movement of the tympanic membrane from a puff of air.[3][6] New discharge not related to otitis externa also indicates the diagnosis.[3]
A number of measures decrease the risk of otitis media including pneumococcal and influenza vaccination, exclusive breastfeeding for the first six months of life, and avoiding tobacco smoke.[3] In those with otitis media with effusion antibiotics do not generally speed recovery.[6][7] The use of pain medications for AOM is important.[3] This may include paracetamol (acetaminophen), ibuprofen, benzocaine ear drops, or opioids.[3] In AOM, antibiotics may speed recovery but may result in side effects.[8] Antibiotics are often recommended in those with severe disease or under two years old. In those with less severe disease they may only be recommended in those who do not improve after two or three days.[6] The initial antibiotic of choice is typically amoxicillin. In those with frequent infections tympanostomy tubes may decrease recurrence.[3]
Worldwide AOM affect about 11% of people a year (about 710 million cases).[9] Half the cases involve children less than five years of age and it is more common among males.[4][9] Of those affected about 4.8% or 31 million develop chronic suppurative otitis media.[9] Before the age of ten OME affects about 80% of children at some point.[4] Otitis media resulted in 2,400 deaths in 2013 – down from 4,900 deaths in 1990.[10]
An integral symptom of acute otitis media is ear pain; other possible symptoms include fever, and irritability (in infants). Since an episode of otitis media is usually precipitated by an upper respiratory tract infection (URI), there often are accompanying symptoms like cough and nasal discharge.[11]
Discharge from the ear can be caused by acute otitis media with perforation of the ear drum, chronic suppurative otitis media, tympanostomy tube otorrhea, or acute otitis externa. Trauma, such as a basilar skull fracture, can also lead to discharge from the ear due to cerebral spinal drainage from the brain and its covering (meninges).
The common cause of all forms of otitis media is dysfunction of the Eustachian tube.[12] This is usually due to inflammation of the mucous membranes in the nasopharynx, which can be caused by a viral URI, strep throat, or possibly by allergies.[13] Because of the dysfunction of the Eustachian tube, the gas volume in the middle ear is trapped and parts of it are slowly absorbed by the surrounding tissues, leading to negative pressure in the middle ear. Eventually the negative middle-ear pressure can reach a point where fluid from the surrounding tissues is sucked in to the middle ear's cavity (tympanic cavity), causing a middle-ear effusion. This is seen as a progression from a Type A tympanogram to a Type C to a Type B tympanogram.
By reflux or aspiration of unwanted secretions from the nasopharynx into the normally sterile middle-ear space, the fluid may then become infected — usually with bacteria. The virus that caused the initial URI can itself be identified as the pathogen causing the infection.[13]
As its typical symptoms overlap with other conditions, such as acute external otitis, clinical history alone is not sufficient to predict whether acute otitis media is present; it has to be complemented by visualization of the tympanic membrane.[14][15] Examiners use a pneumatic otoscope with a rubber bulb attached to assess the mobility of the tympanic membrane.
Acute otitis media in children with moderate to severe bulging of the tympanic membrane or new onset of otorrhea (drainage) is not due to external otitis. Also, the diagnosis may be made in children who have mild bulging of the ear drum and recent onset of ear pain (less than 48 hours) or intense erythema (redness) of the ear drum.
To confirm the diagnosis, middle-ear effusion and inflammation of the eardrum have to be identified; signs of these are fullness, bulging, cloudiness and redness of the eardrum.[11] It is important to attempt to differentiate between acute otitis media and otitis media with effusion (OME), as antibiotics are not recommend for OME.[11] It has been suggested that bulging of the tympanic membrane is the best sign to differentiate AOM from OME [16]
Viral otitis may result in blisters on the external side of the tympanic membrane, which is called bullous myringitis (myringa being Latin for "eardrum").[17]
However, sometimes even examination of the eardrum may not be able to confirm the diagnosis, especially if the canal is small. If wax in the ear canal obscures a clear view of the eardrum it should be removed using a blunt cerumen curette or a wire loop. Also, an upset young child's crying can cause the eardrum to look inflamed due to distension of the small blood vessels on it, mimicking the redness associated with otitis media.
The most common bacteria isolated from the middle ear in AOM are Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis,[11] and Staphylococcus aureus.[18]
Otitis media with effusion (OME), also known as serous otitis media (SOM) or secretory otitis media (SOM), and commonly referred to as glue ear,[19] is a collection of effusion (fluid) that occurs in the middle-ear space due to the negative pressure produced by dysfunction of the Eustachian tube. This can occur purely from a viral URI or bacterial infection, or it can precede and/or follow acute bacterial otitis media.[20] Fluid in the middle ear frequently causes conductive hearing impairment but only when it interferes with the normal vibration of the eardrum by sound waves. Over weeks and months, middle-ear fluid can become very thick and glue-like, which increases the likelihood of its causing conductive hearing impairment.
Early-onset OME is associated with feeding of infants while lying down, early entry into group child care, parental smoking, lack, or too short a period of breastfeeding and greater amounts of time spent in group child care, particularly those with a large number of children, increases the incidences and duration of OME in the first two years of life.[21]
Chronic suppurative otitis media, incorrectly called chronic otitis media or chronic ear infection, involves a hole in the tympanic membrane and active bacterial infection within the middle-ear space for several weeks or more. There may be enough pus that it drains to the outside of the ear (otorrhea), or the pus may be minimal enough to only be seen on examination using the otoscope or, more effectively, with a binocular microscope. This disease is much more common in persons with poor Eustachian tube function and very common in certain races such as Native North Americans. Hearing impairment often accompanies this disease.
It is a primary cause of hearing loss that newly develops in children. An ear wick may be effective or, if not, antibiotics.[22]
Adhesive otitis media occurs when a thin retracted ear drum becomes sucked into the middle-ear space and stuck (i.e., adherent) to the ossicles and other bones of the middle ear.
Acute otitis media
Acute otitis media, myringitis bullosa
Myringitis bullosa in influenza
Chronic otitis media (otitis media chronica mesotympanalis)
Otitis media chronica mesotympanalis
Otitis media chronica mesotympanalis
Otitis media chronica mesotympanalis
Long-term antibiotics, while they decrease rates of infection during treatment, have an unknown effect on long-term outcomes such as hearing loss.[23] This method of prevention has been associated with emergence of antibiotic-resistant otitic bacteria. They are thus not recommended.[11]
Pneumococcal conjugate vaccines when given during infancy decrease rates of acute otitis media by 6%–7% and, if implemented broadly, would have a significant public health benefit.[11][24][needs update] Influenza vaccine is recommended annually.[11]
Risk factors such as season, allergy predisposition and presence of older siblings are known to be determinants of recurrent otitis media and persistent middle-ear effusions (MEE).[25] History of recurrence, environmental exposure to tobacco smoke, use of daycare, and lack of breastfeeding have all been associated with increased risk of development, recurrence, and persistent MEE.[26][27] Thus, cessation of smoking in the home should be encouraged, daycare attendance should be avoided or daycare facilities with the fewest attendees should be recommended, and breastfeeding should be promoted.[26][27]
There is some evidence that breastfeeding for the first year of life is associated with a reduction in the number and duration of OM infections.[28][29] Pacifier use, on the other hand, has been associated with more frequent episodes of AOM.[30]
Evidence does not support zinc supplementation as an effort to reduce otitis rates except maybe in those with severe malnutrition such as marasmus.[31]
Oral and topical pain killers are effective to treat the pain caused by otitis media. Oral agents include ibuprofen, paracetamol (acetaminophen), and opiates. Topical agents shown to be effective include antipyrine and benzocaine ear drops.[32] Decongestants and antihistamines, either nasal or oral, are not recommended due to the lack of benefit and concerns regarding side effects.[33] Half of cases of ear pain in children resolves without treatment in three days and 90% resolves in seven or eight days.[34]
It is important to weigh the benefits and harms before using antibiotics for acute otitis media. As over 80% of acute episodes settle without treatment, about 20 children must be treated to prevent one case of ear pain, 33 children to prevent one perforation, and 11 children to prevent one opposite-side ear infection. For every 14 children treated with antibiotics, one child has an episode of either vomiting, diarrhea or a rash.[35][needs update] If pain is present, treatment to reduce it should be initiated.
The first line antibiotic treatment, if warranted, is amoxicillin.[11] If there is resistance or use of amoxicillin in the last 30 days then amoxicillin-clavulanate or another penicillin derivative plus beta lactamase inhibitor is recommended.[11] Taking amoxicillin once a day may be as effective as twice[36] or three times a day. While less than 7 days of antibiotics have less side effects, more than seven days appear to be more effective.[37] If there is no improvement after 2–3 days of treatment a change in therapy may be considered.[11]
A treatment option for chronic suppurative otitis media with discharge is topical antibiotics. A Cochrane review found that topical quinolone antibiotics can improve discharge better than oral antibiotics.[38] Safety is not really clear.[38]
Tympanostomy tubes (also called "grommets") are recommended in those people who have three or more episodes of acute otitis media in 6 months or four or more in a year, with at least one episode or more attacks in the preceding 6 months.[11] In chronic cases with effusions, insertion of tympanostomy tube into the eardrum reduces recurrence rates in the 6 months after placement[39] but has little effect on long-term hearing.[40] A common complication of having a tympanostomy tube is otorrhea, which is a discharge from the ear.[41]
Oral antibiotics should not be used to treat uncomplicated acute tympanostomy tube otorrhea.[41] Oral antibiotics are not a sufficient response to bacteria that cause this condition and have significant side effects including increased risk of opportunistic infection.[41] In contrast, topical antibiotic eardrops can treat this condition.[41]
Complementary and alternative medicine is not recommended for otitis media with effusion because there is no evidence of benefit.[20] An osteopathic manipulation technique called the Galbreath technique[42] was evaluated in one randomized controlled clinical trial; one reviewer concluded that it was promising, but a 2010 evidence report found the evidence inconclusive.[43]
Complications of acute otitis media consists of perforation of the ear drum, infection of the mastoid space behind the ear (mastoiditis), and more rarely intracranial complications can occur, such as bacterial meningitis, brain abscess, or dural sinus thrombosis.[44] It is estimated that each year 21,000 people die due to complications of otitis media.[45]
In severe or untreated cases, the tympanic membrane may perforate, allowing the pus in the middle-ear space to drain into the ear canal. If there is enough, this drainage may be obvious. Even though the perforation of the tympanic membrane suggests a highly painful and traumatic process, it is almost always associated with a dramatic relief of pressure and pain. In a simple case of acute otitis media in an otherwise healthy person, the body's defenses are likely to resolve the infection and the ear drum nearly always heals. An option for severe acute otitis media in which analgesics are not controlling ear pain is to perform a tympanocentesis, i.e., needle aspiration through the tympanic membrane to relieve the ear pain and to identify the causative organism(s).
Children with recurrent episodes of acute otitis media and those with otitis media with effusion or chronic suppurative otitis media have higher risks of developing conductive and sensorineural hearing loss. Globally approximately 141 million people have mild hearing loss due to otitis media (2.1% of the population).[46] This is more common in males (2.3%) than females (1.8%).[46]
This hearing loss is mainly due to fluid in the middle ear or rupture of the tympanic membrane. Prolonged duration of otitis media is associated with ossicular complications and, together with persistent tympanic membrane perforation, contributes to the severity of the disease and hearing loss. When a cholesteatoma or granulation tissue is present in the middle ear, the degree of hearing loss and ossicular destruction is even greater.[47]
Periods of conductive hearing loss from otitis media may have a detrimental effect on speech development in children.[48] Some studies have linked otitis media to learning problems, attention disorders, and problems with social adaptation.[49] Furthermore, it has been demonstrated that patients with otitis media have more depression/anxiety-related disorders compared to individuals with normal hearing.[50] Once the infections resolve and hearing thresholds return to normal, childhood otitis media may still cause minor and irreversible damage to the middle ear and cochlea.[51]
Acute otitis media is very common in childhood. It is the most common condition for which medical care is provided in children under five years of age in the US.[52] Acute otitis media affects 11% of people each year (709 million cases) with half occurring in those below five years.[45] Chronic suppurative otitis media affects about 5% or 31 million of these cases with 22.6% of cases occurring annually under the age of five years.[45] Otitis media resulted in 2,400 deaths in 2013 — down from 4,900 deaths in 1990.[10]
Otitis media is Latin for "inflammation of the middle ear".
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リンク元 | 「慢性化膿性中耳炎」 |
関連記事 | 「suppurative」「chronic」「media」「med」 |
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