Saturday, 29 September 2018

Otitis media inflammation of the middle ear

Otitis media



1.     Otitis media is a group of inflammatory diseases of the middle ear. There are two main types - acute variety and chronic category. In Acute there is “acute otitis media (in short- AOM )”, and “otitis media with effusion  (in short- OME )”. In chronic variety there lies“ chronic otitis media ( in short –CSOM)”. AOM is an infection of abrupt onset that usually presents with ear pain, decreased appetite -eating and  fever may also be present. OME is typically not associated with these symptoms, occasionally only a feeling of fullness is described. OME is defined as the presence of non-infectious fluid in the middle ear for more than three months. Chronic suppurative otitis media ( in short -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. All three (AOM, OME, CSOM) may be associated with hearing loss.  The cause of AOM is related to anatomy and immune function. Either bacteria or viruses may be involved. OME frequently occurs following AOM and may be related to viral upper respiratory infections, irritants, or allergies. Looking at the eardrum is important for making the correct diagnosis. Signs of AOM include bulging or a lack of movement of the tympanic membrane from a puff of air, recent discharge  also indicates the diagnosis of AOM.

2.    A number of measures decrease the risk of otitis media including pneumococcal and influenza vaccination, and avoiding smoke. In OME antibiotics do not generally get speedy recovery. The use of pain medications for AOM may include paracetamol (acetaminophen), ibuprofen, benzocaine ear drops, or opioids. In AOM, antibiotics may speed recovery but may result in side effects. Antibiotics are often recommended in those with severe disease. In those with less severe disease they may only be recommended in those who do not improve after two or three days. The initial antibiotic of choice is typically amoxicillin.  

Signs and symptoms
3.    An integral symptom of AOM is ear pain other possible symptoms include fever, and irritability .Since an episode of otitis media is usually precipitated by an upper respiratory tract infection (URTI), there often are accompanying symptoms like cough and nasal discharge.

Mechanism of occurrence of discharge   - pathophysiology

4.  When an infection attacks the upper respiratory tract(URTI) the infection from the Nasopharynx / Oropharynx (Throat/Nose) climbs-up to the Eustachian tube( I,e.the tube connecting the throat, back of nose to the ear). Because of this infection the Eustachian tube gets blocked and the gasses inside the middle ear get’s absorbed into the tissues , thereby creating negative pressure ,and accumulation of fluid in the middle ear. This fluid may or may not get infected .When it gets infected it results into PUS (SLIDE A, B) . The pus creates  pressure over the tympanic membrane, it therefore bulges outwards ( SLIDE C). The bulging of tympanic membrane makes it vulnerable to and the blood supply to the tympanic membrane gets strangulated-cutting down the blood supply,(SLIDE D) leading to avascular necrosis in a portion of the tympanic membrane- thus creating PERFORATION in the tympanic membrane called ‘SPONTANEOUS PERFORATION”(SLIDE E). This perforation allows the fluid/ infected fluid to flow out into external ear in form of a DISCHARGE. Thus a discharge from the ear  precedes in AOM -acute otitis media with perforation of the ear drum . Other conditions with ear discharge are:- CSOM- chronic suppurative otitis media, tympanostomy tube otorrhea, or accompanying inflammation of the external ear - acute otitis externa.

Slide A : diagrammatic representation of the ear anatomy and pus in the middle ear.

Slide B – Diagrammatic representation depicting the three parts of the ear viz external, middle and internal ear, with inflammation, fluid accumulation of the middle ear.

Slide C : Bulging of tympanic membrane due to accumulation of fluid in middle ear- acute otitis media- suppurative.


Slide D : depicting bulging leading to avascular necrosis, just prior to perforation.


Slide E : Slide depicting the  small central perforation.

5.    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.

Diagnosis
6.    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. Examiners use a pneumatic otoscope with a rubber bulb attached to assess the mobility of the tympanic membrane.

7.     Acute otitis media in children with moderate to severe bulging of the tympanic membrane or new onset of otorrhea - drainage. 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.

8.    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. It is important to attempt to differentiate between acute otitis media and otitis media with effusion (OME), as antibiotics are not recommend for OME. It has been suggested that bulging of the tympanic membrane is the best sign to differentiate AOM from OME.

9.    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 / a wire loop/ swab holder.

          Acute otitis media
10.                 The most common bacteria isolated from the middle ear in AOM are Streptococcus pneumoniaeHaemophilus influenzaeMoraxella catarrhalis, and Staphylococcus aureus.

Chronic suppurative otitis media
11.           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. Hearing impairment often accompanies this disease.

Prevention
12.                  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). 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. 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, avoidance of nose blowing/sniffing.

Management
13.                  Oral and topical pain killers are effective to treat the pain caused by otitis media. Oral agents include ibuprofenparacetamol (acetaminophen), and opiates. Topical agents shown to be effective include antipyrine and benzocaine ear drops.  Half of cases of ear pain  resolves without treatment in three days and 90% resolves in seven or eight days.

Antibiotics
14.                  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 % must be treated to prevent one case of ear pain, 33 % to prevent one perforation, and 11 % to prevent one opposite-side ear infection. For every 14 %patient treated with antibiotics, one has an episode of either vomiting, diarrhea or a rash. If pain is present, treatment to reduce it should be initiated.

15.                  Antibiotics should be prescribed for severe bilateral or unilateral disease in all patients with severe signs and symptoms, such as moderate to severe ear pain and high fever.

16.                  When non-severe unilateral acute otitis media is diagnosed either antibiotic therapy is given or observation with close follow-up based on joint decision making between parent(s)/caregiver.

17.Patients with non-severe disease can have either antibiotics or observation.

18.                 The first line antibiotic treatment, if warranted, is amoxicillin. 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. Taking amoxicillin once a day may be as effective as twice 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. If there is no improvement after 2–3 days of treatment a change in therapy may be considered.

Outcomes-Complications
19.                  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 meningitisbrain abscess, or dural sinus thrombosis. It is estimated that each year 21,000 people die due to complications of otitis media.

Membrane rupture
20.                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. The perforation of the tympanic membrane 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 AOM -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).

Hearing loss
21.                  Patients with recurrent episodes of  AOM-acute otitis media and those with OME-otitis media with effusion or CSOM-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). This is more common in males (2.3%) than females (1.8%).

22.                 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.

23.                 Periods of conductive hearing loss from otitis media may have a detrimental effect. Some studies have linked otitis media to learning problems, attention disorders, and problems with social adaptation. Furthermore, it has been demonstrated that patients with otitis media have more depression/anxiety-related disorders compared to individuals with normal hearing. 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.

Epidemiology
24.                 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, which at times has relapsing phenomenon linked to in adulthood. Acute otitis media affects 11% of people each year (709 million cases) with half occurring in those below five years. 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. Otitis media resulted in 2,400 deaths in 2013 — down from 4,900 deaths in 1990.

Etymology
Otitis media is Latin for "inflammation of the middle ear"

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