Bullous myringitis describes an inflammation of the tympanic membrane characterized by the appearance of fluid-filled blisters on this organ. It thus refers to clinical presentation rather than to etiology.
Symptom onset is mostly acute and only one ear is affected . While older children, adolescents and adults usually present with throbbing otalgia, a feeling of increased pressure, fullness or ear congestion and muffled hearing, young pediatric patients express their discomfort by feeding and sleeping difficulties and constant crying. Otorrhea and pruritus may be present but are not exclusion criteria. Some patients claim dizziness and vertigo which may result from involvement of the organ of equilibrium.
Anamnesis often reveals recent upper respiratory tract infections. Also, many BM patients use to regularly clear their external auditory channels or report other traumas.
Otoscopic examination reveals fluid-filled blisters between the outer epithelial and middle fibrous layer of the tympanic membrane. In a minority of BM patients, such bullae are also present in the external auditory meatus. Number and size of blebs may vary; they do not necessarily cover the whole tympanic membrane. A bulging tympanic membrane may indicate otitis media and middle ear effusion.
BM is diagnosed after otoscopic examination and visual evaluation of the tympanic membrane. These may require cleaning of the external auditory meatus from any discharge and debris. Special care has to be taken if the condition of the tympanic membrane is not easily assessable because it cannot be visualized before the aforementioned procedure took place.
In order to determine the extent of the disease and to identify its cause, additional diagnostic measures may be necessary.
Pneumatic otoscopy and tympanometry allow for assessment of tympanic membrane mobility and are routinely used to diagnose otitis media and associated middle ear effusion. Acoustic otoscopy may also be employed to this end. This method is based on measuring the tympanic membrane's ability to react to sound waves.
Bacterial cultures established from samples obtained from the external auditory channel or the middle ear (possibly requires tympanocentesis) not only allow to determine the causative agent but are also of great help when deciding on a specific therapeutic approach. Protein content, albumin to immunoglobulin ratio and specific gravity of these samples may be measured to distinguish exudate from transudate if there is any doubt.
An audiogram may be recorded to determine the extent of hearing loss and to locate its cause.
Moderate to severe cases may indicate advanced diagnostic imaging. Otomicroscopy and otoendoscopy may provide detailed information regarding the condition of outer and middle ear. If compromise of neighboring tissues, e.g., adjacent bones and intracranial structures such as meninges, is suspected, magnetic resonance imaging and computed tomography scans should be carried out.
Adequate treatment should be provided as soon as possible in order to prevent spread of infection and inflammation to adjacent tissues. Treatment of BM is mainly based on topical and possibly systemic application of antibiotics and non-steroidal anti-inflammatory drugs.
Ideally, antimicrobials are chosen based on an antibiogram, but antibiotics are often prescribed before such an analysis is available. If symptoms subside over the course of few days - which is the case in most BM patients - antibiotic therapy doesn't need to be changed and should be continued as originally planned. However, resistant bacteria have been isolated from otitis media and BM, notably methicillin-resistant Staphylococcus aureus, and may account for lack of response to therapy.
Additionally, patients may benefit from ear cleaners and antihistamines.
More severe cases associated with middle ear effusion may require myringotomy. This procedure accelerates pressure reduction and avoids spontaneous bursting of the tympanic membrane. The incision into the tympanic membrane usually heals fast and without complications. While this is certainly a benefit with regards to healing, it may interfere with continuous drainage of the middle ear. In this context, a small tube may be inserted into the tympanic membrane to maintain the possibility for fluid discharge. This tympanostomy may, however, lead to permanent perforation of the tympanic membrane and should thus not be carried out routinely.
Other surgical interventions are rarely needed to treat BM, but may be indicated if the tympanic membrane spontaneously bursts. Here, chronic otitis media and myringitis may be prevented by myringoplasty, i.e., closure of the perforation of the tympanic membrane. Myringoplasty is considered a very successful procedure and up to 90% of patients treated in this manner re-form their tympanic membrane.
Prognosis of BM is usually favorable. Indeed, the condition is often self-limiting, but adequate treatment is indicated to relieve otalgia and to prevent serious complications:
BM is primarily caused by infectious agents. And although there is general agreement on this fact, a literature review reveals that opinions regarding its precise causative agents differ widely. Some consider BM to be mainly triggered by viral agents, but more recent research argues for bacteria to account most commonly for this condition. There has been considerable disagreement regarding the role of Mycoplasma pneumoniae in BM and contrary to what has been assumed for a long time, this species is now considered to rarely cause BM  .
Presumably, BM is triggered by the same bacterial and viral agents that also cause otitis media. This is consistent with BM being either a specific form or partial finding of otitis media and externa. Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis are most frequently isolated from otitis media . Furthermore, Staphylococcus aureus, other streptococci and staphylococci as well as Enterobacteriaceae and Pseudomonas aeruginosa have been described in this context. As has been indicated above, Mycoplasma pneumoniae may be found but is not pathognomonic for BM.
Otitis media and BM often occur following upper respiratory tract infections. Here, pathogens such as adenovirus, coronavirus, rhinovirus and parainfluenza virus may ascend towards the middle ear through the Eustachian tube.
Fungal infections have been described to affect the external auditory meatus, but a causal relation to BM has not yet been proven.
A Finnish research group reported an incidence of more than 5 per 100 person-years . Although this study was focused on children aged less than 2 years, it does point out that BM is not a rare disease. Most BM patients are indeed children; adolescents and young adults are frequently affected, too. Thus, the overall incidence comprising all age groups may be somewhat lower than the above given value.
According to the above mentioned study, BM is diagnosed in about 5% of all otitis media cases.
BM more often occurs in cold and damp seasons and anamnesis frequently reveals recent upper respiratory tract infections.
BM is characterized by blisters or bullae that develop between the outer epithelial layer (Stratum corneum) and the middle fibrous layer (Lamina propia). They may be filled with serous, serosanguineous or sanguineous fluid. Myringitis and tissue stretching typically cause severe, throbbing otalgia.
As has been indicated above, BM is often associated with otitis media. The latter, in turn, is commonly related with functional impairment of the Eustachian tube, reduced aeration of the middle ear, and ascend of pathogens through the auditory tube. Excess opening of the tube may facilitate infection of the middle ear. These facts also explain why otitis media and BM often occur after upper respiratory tract infections. With regards to infectious otitis externa, causative agents may enter the external auditory channel and reach the tympanic membrane.
To date, it is not yet clear why some cases of otitis media or otitis externa are associated with tympanic bullae formation and others aren't.
Patients should be advised on how to clean their external auditory channels without inflicting trauma. Usage of ear plugs may prevent water from entering the ear and contributes to prevention of BM. This measure as well as the use of isopropyl alcohol or similarly acting ear drops is particularly recommended to those patients who suffer from recurrent ear infections.
Any measure to improve immunity may help to directly reduce the incidence of ear infections and may also diminish the rate of respiratory tract infections and subsequent BM.
The middle ear comprises tympanic membrane and ossicles, whereby the latter are located in the tympanic cavity and forward auditory input towards the cochlea. The Eustachian tube connects tympanic cavity and nasopharynx and although this organ is not considered part of the middle ear, it fulfills a variety of physiological and pathophysiological functions that significantly affect the condition of the latter. For instance, it allows for pressure compensation and drainage of fluids that would otherwise accumulate in the tympanic cavity.
Inflammation of the middle ear is termed otitis media and is most frequently caused by microorganisms. Otitis media frequently involves the tympanic membrane and causes myringitis. In some cases, lesions of the tympanic membrane present as fluid-filled bullae and the condition is then designated bullous myringitis (BM) . While most commonly, these blisters are filled with serous fluids, hemorrhagic forms of BM have been reported . To date, there is no general consensus whether BM is indeed an own entity or whether it is merely a partial finding in patients suffering from otitis media. In fact, the bullous inflammation may not be restricted to the tympanic membrane but may spread to the external auditory channel and these patients are then diagnosed with otitis media and externa .
Similar to otitis media itself, BM is thought to be primarily triggered by infection with bacteria or viruses. A variety of etiologic agents has been described and will be mentioned below. The condition is associated with severe otalgia and fever. Children are affected more frequently than adults, although BM is not a rare finding in any age group. BM is usually self-limiting, but pain, general discomfort and the risk for serious complications nevertheless indicate at least supportive treatment and, if possible, causative therapy.
Bullous myringitis (BM) refers to a certain type of inflammation of the tympanic membrane that is characterized by the appearance of fluid filled blebs ("bullae") between the outer epithelial and middle fibrous layer of this organ.
BM is often associated with inflammations of the middle or outer ear. All these conditions are primarily triggered by bacteria and viruses that may ascend through the auditory tube that connects nasopharynx and middle ear or that may simply enter via the external auditory channel.
Interestingly, the medical history of BM patients frequently reveals recent infections of the upper respiratory tract. Here, the causative agent of the latter presumably ascended to the middle ear. Thus, one and the same pathogen probably triggered both conditions.
This disease is most frequently detected in young children. They may express their discomfort in form of feeding and sleeping problems and continuous crying. Children are also observed to frequently touch their aching ear. BM is a painful condition often described as a feeling of increased pressure, fullness or ear congestion. The throbbing pain is felt in one ear only and sets in rather suddenly. A slight hearing loss may result from BM and patients often report muffled hearing. Because the organ of equilibrium is also located in the ear, dizziness and vertigo are not uncommon in middle ear inflammation and BM. Discharge from the external auditory channel may be noted.
The condition is generally diagnosed upon visual inspection of the tympanic membrane by means of an otoscope. Sometimes, fluids and debris accumulated in the external auditory channel do not allow for visualization of the tympanic membrane and have to be removed first.
While fluid-filled blebs are characteristic for BM, the physician may apply additional therapeutic measures to support their diagnosis of otitis media. Here, tympanometry, pneumatic and acoustic otoscopy shall be named as possible forms of examination.
In severe cases, when the physician suspects that adjacent osseous tissues or meninges are compromised by infection and inflammation, magnetic resonance imaging and computed tomography scans may be carried out.
Although BM is usually self-limiting, drug therapy is indicated to avoid serious complications such as spread to neighboring tissues and hearing loss. Most frequently, application of antibiotics and non-steroidal anti-inflammatory drugs is sufficient to treat the condition.
Inflammation and effusion of the middle ear may require a small incision into the tympanic membrane in order to allow drainage of accumulated fluids. On the other hand, perforations of the tympanic membrane may be closed during surgical interventions.