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HARP. Case Notes CONDITION: Acute otitis media Alternative names: Acute suppurative otitis media (AOM). Suppurative means containing bacterial infection (Gelfand, 2009) Acute purulent (suppurative) otitis media (Gelfand, 2009) Definition: Otitis media refers to the inflammation of the middle ear, including the tympanic membrane. Acute otitis media has a rapid onset of symptoms. The method of distinguishing between acute otitis media, chronic otitis media or sub-acute otitis media is relative to the length of time the condition continues. If the condition lasts up to three weeks then it is considered to be acute otitis media. If it lasts for more than twelve weeks then it is known as chronic otitis media. For intermediate durations it is known as sub-acute otitis media (Gelfand, 2009) There are also two grades of AOM: severe and moderate. AOM becomes classed as severe when otalgia is severe or when the oral temperature reaches 39C and above or both. (Bluestone, C.B, Klein, J.O., 2007). However as children commonly suffer from AOM it may be difficult to assess their perception of the pain and so this may be an invalid criterion. Epidemiology: Common condition with a high incidence but very low mortality rate (O’Neill, 1999) In the UK 30% children under three visit the GP with acute otitis media each year (O’Neill, 1999) Most common in children aged 6-18 Months (Klein, 1994), although can occur at any age (Pavlovcinova et.al, 2008) More common in boys (Klein, 1994) Higher prevalence in winter (Klein, 1994) Symptoms: Fever Otalgia (ear pain) Temporary conductive hearing loss HARP. Case Notes Sensation of aural fullness Young children have been reported to pull on their ears (Madell & Flexer, 2008) Signs: Hyperemia, which is an enlargement of tissues with blood; especially the tympanic membrane Exudation may occur after several days. This is where the middle ear fills with fluid containing white and red blood cells and mucus. This subsequently leads to the tympanic membrane appearing red and thickened with landmarks difficult to identify. This tends to cause increased pain, fever and a conductive hearing loss (Gelfand, 2009) The tympanic membrane may also bulge outwards due to the pressure placed on it from exudation. This building pressure may cause the tympanic membrane to rupture, giving out a discharge known as otorrhea. In some patients it is preferable for a surgeon to perform a procedure known as myringotomy, where a small incision of the tympanic membrane is performed to relieve pressure and encourage healing (Hughes & Pensak, 2007) Chronic otitis media is often associated with a perforated eardrum (Gelfand, 2009). Pathophysiology: AOM is an inflammatory condition involving the membrane of the middle ear, including the tympanic membrane. It is caused by a bacterial infection, usually brought on during an upper respiratory tract infection (Hughes, & Pensak, 2007 & Gelfand, 2009). Negative middle ear pressure is thought to develop as a result of the respiratory infection and bacteria brought into the middle ear (WHO/CIBA Foundation, 1996). The bacteria are suggested to come from the back of the nose and throat (nasopahrynx) and travel trough the Eustachian tube to the middle ear (Hughes & Pensak, 2007 & NHS: Acute otitis media, 2009). Hughes and Pensak (2007) suggested that there are three types of predominant bacteria that cause acute otitis media. These are: Streptococcus pneumonia (35%), Haemophilus influenza (23%) and Moraxella catarrhalis (14%). However according to Gelfand (2009) Branhamella catarrhalis may HARP. Case Notes also be a significant cause. The evidence from Gelfand (2009) and Hughes & Pensak (2007) would suggest that the bacteria Streptococcus pneumonia and Haemophilus influenza are the most common in causing AOM. The high prevalence rates in young children may be due to the presence of a shorter Eustachian tube that is also at a less vertical angle compared to adults (Fry & Sandler,1993). This means that bacteria are able to move into the Eustachian tube and reach the middle ear more easily than in adults. There is some suggestion that smaller Eustachian tubes may become easily blocked, preventing ventilation and allowing bacteria to be trapped and multiply (NHS: Acute Otitis Media, 2009). In some cases a previous infection may weaken a child’s immune system and make it more difficult to fight off the bacterial infection in the middle ear (NHS: Acute Otitis Media, 2009). Complications of otitis media: AOM is unlikely to cause any permanent damage and 80% of cases heal with no complications and without the need for medical intervention (Alberti, n.d.). However complications can occur and include: Progression to chronic otitis media (WHO/CIBA Foundation, 1996). The condition may initially develop as an acute case of AOM but progress to a chronic or long term infection of the middle ear. Perforation of the eardrum can also occur. The movement of the ossicles may also be impacted as complications such as tympanosclerosis or ossicular chain discontinuity (Gelfand, 2009) Facial paralysis if the infection spreads through the fallopian canal to where the seventh cranial nerve passes through (Gelfand, 2009). Spread of the infection to the inner ear may result in labyrinthitis (Gelfand, 2009). Symptoms of labyrinthitis include severe vertigo, nausea, vomiting, fatigue and uncontrollable nystagmus (NHS: Labyrinthitis, 2009). The infection spreading to the mastoid, known as mastoiditis. Infection of the central nervous system can occur following mastoiditis (Gelfand, 2009). Gelfand (2009) also suggests that a sensorineural loss can occur if the bacteria are spread to the inner ear. HARP. Case Notes On a further note conductive lesions may impact on bone conduction results, meaning that some of the results believed to be from a sensorineural hearing loss, may in fact be due to conductive lesions. If the hearing loss is not treated then learning may be hindered during the temporary hearing loss. In some language development may also suffer. Management: Acute Otitis Media can be treated with oral antibiotics (Gelfand, 2009 p 177) or ear drops. This is because studies and real life examples have shown that treatment by antibiotics show a decline in suppurative (formation of pus) complications and improved patient outcomes. Also if it is left untreated complications may arise and these cannot be predicted so antibiotics are given as a precautionary measure. The antibiotics given should cover the common bacteria that cause acute otitis media but it needs to be individualised to each patient; especially for children taking into account of allergies and tolerance (Donaldson, 2009).Common antibiotics are amoxicillin, ampicillin and erythtomycin (Gelfand, 2009, p 177). HARP. Case Notes CONDITION:Acute otitis media (AOM) in right ear Notes: There are varying stages of AOM and patients will present with varying symptoms and results. In order to show this four stages of AOM have been identified. These are; a) developing AOM with patient reporting mild earache, b) obvious case of AOM with bulging tympanic membrane, patient in obvious pain and discomfort, c) ruptured tympanic membrane as a result of pressure (does not occur in all cases) and d) recovering case of AOM. These stages will be referred to throughout. Otoscopy Right Left Figure 1: ‘Stage b’ otoscopy findings Notes: The figure above is an example of a ‘stage b’ case of AOM with visual indications of AOM. At this stage the tympanic membrane may appear reddened and may also bulge due to pressure from mucus and blood cells in the middle ear space. The malleus may not be identifiable in the affected ear. The tympanic membrane may also appear opaque (Block & Harrison, 2005). However in other stages findings from otoscopy may not be as identifiable and figure 2 below highlights other potential findings. Figure 2: Otoscopy results from the right ear 1) 2) HARP. Case Notes 3) Figure 2 shows potential findings from otoscopy at different stages of AOM. 1) This is representative of what could be seen in a ‘stage a’ case of AOM. Here there is come redness and bulging of the tympanic membrane yet landmarks such as the umbo and light reflex are still identifiable. 2) This image is representative of a ‘stage c’ case of AOM. The pressure from fluid behind the tympanic membrane has caused it to rupture and fluid is clearly visible around the membrane. Considerable care should be taken to minimise the risk of cross-infection and all equipment must either be disposed of or sterilised according to hospital procedure. 3) This image is representative of a ‘stage d’ case of AOM when the patient is recovering from the episode. Some scarring may be evident, although many of the landmarks such as the incus and Pars tensa are now visible. Problems associated with testing: Patients may have otalgia, and if so careful examination may be required. Young children may be reluctant to allow otoscopy to be performed and caution should be taken to not cause the patient further discomfort or anxiety. If a child has recently been crying or had a fever then this can cause a slight reddening of the tympanic membrane and should not be confused with a sign of AOM (Subcommittee on Management of Acute Otitis Media, 2004) Alternative tests: Pneumatic Otoscopy can be carried out by creating a seal in the ear canal in order to alternatively apply positive and negative pressures in the canal whilst observing the tympanic membrane movement. This test can help to indicate the presence of fluid in the middle ear by observing reduced tympanic membrane movement and therefore can be useful in indicating the presence HARP. Case Notes of AOM. (Stool & Berg, 1994, pp30) Tuning forks Figure 3: ‘Stage a, b and c’ tuning fork results Right Left Weber: Right ear Rinne: Negative Positive Rinne Rinne Notes: Sound lateralisation to the right ear during the Weber test indicates a conductive loss and this supports the negative Rinne result for that ear, which also indicates a conductive loss on the right. These results are likely to be the case for stages a, b and c. In stage d the clearing of fluid from the middle ear and the healing of any perforation means that the patient should have regained their ‘normal’ thresholds and so have negative Rinne results for both ears and the Weber test should be loudest centrally if they have symmetrical hearing. Reliability of test: As young children are typically affected by AOM they may be unable to distinguish which ear sound lateralises to and by which method the sound is loudest in, so both tests may not give reliable results in a younger age group. There are also general limitations of these tests, including the unreliability of the tone as this varies depending on the force used (Gelfand, 2009). Gelfand (1977, cited in Gelfand, 2009) also found that the Rinne test may only correctly diagnose a conductive loss if the air-bone gap is up to 60 dB when using a 512 Hz tuning fork. Therefore these tests have variable results and may explain why the British Society of Audiology (BSA) states that they should only be used to “establish the probable presence or absence of a significant conductive… loss”. Alternative tests: Objective tests that do not require a response may be more useful in children in order to determine the presence of AOM. Such tests include Otoacoustic emissions, which can determine if there is a conductive loss. HARP. Case Notes Pure tone audiometry and uncomfortable loudness levels Figure 4: ‘Stage b’ audiogram Notes: Masking was required at 500, 1000, 2000 and 4000 Hz due to the presence of a 30dB or greater air-bone-gap in figure 3. The audiorgram shape may appear to be flat or ‘tented’, with a peak in the mid-frequencies (Gelfand, 2009), with a mild to moderate conductive loss (Alper et. Al, 2004). Some patients may have a sensorineural component to their loss (although not indicated in the audiogram above) and this is thought to be caused by the transfer of toxins to the inner ear (Gelfand, 2009). Figure 5, below, highlights the varying audiogram shapes and levels which may be seen at the different stages of AOM. Figure 5: Right ear audiogram results for different stages of AOM 1) 2) HARP. Case Notes 3) Figure 5 highlights the different stages of AOM. 1) This is an adapted example of a ‘stage a’ or developing case of AOM. In this case there is a clear peak at 1000 Hz and there is an air bone gap, although it is smaller than that seen in figure 4 above. Masking was still required at 500, 2000 and 4000 Hz. 2) This is an adapted case of a ‘stage d’ or recovering case of AOM. Here the air bone gap is no longer present and audiometric thresholds have been restored to within normal thresholds. 3) This is an adapted example of a sensorineural loss related to AOM (Gelfand, 2009). Here the spread of toxins to the cochlea has led to a moderate sensorineual hearing loss (BSA Guidelines, 2004). Problems associated with testing: As this test requires patient co-operation and understanding it is therefore not suitable for younger children. Alternative tests: If a patient is too young to perform Pure Tone Audiometry (PTA) then tympanometry can be used to ascertain the condition of the tympanic membrane. However tympanometry should not be carried out when there is an active infection. For children over 2 and a half years adaptations of PTA such as the McCormick toy test or conditioned play audiometry may be more suitable to assess their hearing. The McCormick toy test enables an estimation of hearing threshold in 6 dB steps using seven ‘pairs’ of toys with similar vowel sounds and different consonants. An automated voice names the toy and the child should then point to the toy they heard. Care must be taken beforehand that the child knows the name of each toy to prevent confusion and invalid results. Conditioned play audiometry sees the child conditioned to hold a toy at their ear and drop it into a bucket when they hear HARP. Case Notes a sound (Stach & Ramachandran, 2008). The sounds become progressively quieter until an estimation of their threshold is found. The choice of PTA in young children varies for each child and is dependent on their age and cognitive level. Tympanometry Notes: Tympanometry should not be carried out on patients with a current ear infection, such as AOM. This also includes patients who report ear tenderness and pain during history taking. If tympanometry was carried out in a patient with a developing case of AOM, who reports little or no pain in clinic (‘stage a’), then a flat tympanometry shape is likely to be seen. This is indicated in figure 6 below. Figure 6: A ‘stage a’ tympanogram The typmanometry results show that the right ear has a flat trace. The ear canal volume is within the normal range of 0.5-1ml for children and so the results indicate that there is fluid behind the right tympanic membrane. The results from the left ear indicate a normal tympanogram shape, classed as a type ‘A’ tympanogram (Jerger, 1970, cited in Katz et. Al, 2009). Notes on testing method: A screening mode was used in order minimise the time that the young patient spent with the probe in their ear. This is a potential problem when dealing with paediatric patients but the faster mode does slightly help to overcome this. HARP. Case Notes Acoustic reflexes Notes: Acoustic reflexes should also not be performed in patients with current ear infections, including AOM. If acoustic reflex testing were to be carried out on a ‘stage a’ patient, then figure 7 below highlights some possible findings: Figure 7: Possible acoustic reflex thresholds in a ‘stage a’ patient Threshold Right Probe ear contralateral ipsilateral 85 dB X 80 X Left ipsilateral contralateral 1000 Hz 90 dB X 2000 Hz 90 X Results were obtained for the left ipsilateral reflex and the contralateral right reflex at 1000 and 2000 Hz. Both of these thresholds were within the normal threshold range of 75-90 dB Hearing Level (HL) for pure tone sounds. However no results were obtained for the right ipsilateral and left contralateral reflex at 1000 and 2000 Hz. The stimulus ear principle suggests that a conductive loss in the stimulus ear will raise the acoustic reflex by the level of the air bone gap (Katz et. al, 2009). In this case as the air bone gap is 10-15 dB and acoustic reflex thresholds were unable to be reached as testing was stopped at 100 dB to limit the level of noise exposure. Testing was only carried out at 1000 and 2000 Hz as the results were similar and no further testing was necessary. Otoacoustic emissions Notes: It would not be suitable to perform Otoacoustic emissions (OAE’s) testing in ‘stage b and d’ where the patient may be in pain and the risk of infecting the probe and having to decontaminate the equipment is high. Performing OAE’s in these patients would also not inform the tester of any new or additional information that that they have already gained from otoscopy and PTA. However they may be performed in ‘stage a or d’ cases as shown in figure 8, below. HARP. Case Notes Figure 8: Otoacoustic emissions results form a ‘stage a’ case of AOM Definitely present Possibly present Right Left Absent Yes Yes Transient Evoked Otoacoustic emissions (TEOAE’s) testing was carried out between 500 Hz to 4 kHz. ILO 292 measurement system was used. A standard non-linear stimulus paradigm was used at a rate of 50 clicks per second in order to minimise the risk of stimulus artefacts. Definition of a present TEOAE was based on the reproducibility percentage with values above considered to be a possible TEOAE, above 75% a definite TEOAE and below 50% the procedure was repeated once and then deemed to be too noisy to obtain an accurate measurement. It was also based on the dispersion of the TEOAE waveform with high frequency components appearing first, followed by low frequency components. The overall shape of the OAE was also taken into account. This test is particularly useful in children, as it does not require patient response (OAE Guide, 2009) The presence of a definite TEOEA in the left ear indicates that outer hair cells present in the patients cochlear are actively amplifying sound. From this we can invoke that this patient has relatively ‘normal’ hearing. In babies and children the amplitude of the OAE may be greater than that seen in the adult population. However in the right ear there is an absent OAE. Using evidence from history taking, otoscopy and PTA it is assessed that the reason for the absent OAE is due to the presence of a conductive hearing loss, as the result of the patients AOM. OAE’S are usually absent if there is an air bone gap of 15 dB or greater (Owens et. al, 1992; Prieve, 1992; Kemp et. al, 1990; Cullington et. al, 1998, all cited in Hall, 2000). In AOM this absent OAE is because the build up of pus and fluid reduces the level of the click stimulus reaching the cochlea and also greatly reduces the level of the OAE returning back to the External auditory meatus (ear canal). There may well be a fully HARP. Case Notes functioning cochlea and outer hair cells but the conductive loss has reduced the OAE to below the noise floor and so an OAE is not picked up. Problems associated with testing: Physiological noise from the patient may impact on test results. The test environment must also be acoustically silent (OAE’s for Otolaryngologists, 2009). General comments: Then diagnosis of AOM should only be made following a battery of audiological tests, such as those indicated above. Differential diagnosis should be considered with conditions that give similar results. Medical concerns should be referred to ENT. HARP. Case Notes Sources of evidence: A guide to: Otoacoustic Emissions (OAE’s) for Otolaryngologists, 2009, Maico Diagnostics, USA, Retrieved 28th April 2009 from: http://www.maicodiagnostics.com/eprise/main/_downloads/us_en/Documentation/OAEOtolaryn gologistsbooklet.pdf Alberti, P.W., n.d., The Pathophysiology of the Ear, World Health Organisation (WHO) occupational health report, Retrieved 27th April 2010 from: http://www.who.int/occupational_health/publications/noise3.pdf Alper, C.M., Bluestone, C.D., Johar, J.E., Mandel E.M. & Casselbrant, M.L., 2004, Advanced therapy in Otitis Media, Illustrated edn, BC Decker Publishers, USA, pp 419-420 Block, S & Harrison, C.J., 2006, Diagnosis and Management of Acute Otitis Media, 3rd edn, Professional Communications Incorporated, USA, pp 11-12 Bluestone C.D., Klein J.O., 2007, Otitis media in infants and children, 4th Ed., BC Decker: Hamilton Ontario, Canada, pg 271 BSA Recommended procedure, 2004, Pure tone air and bone conduction threshold audiometry with an without masking and determination of uncomfortable loudness levels, pg 17 Donaldson, J.D., 2009, Middle Ear, Acute Otitis Media, Medical Treatment, emedicine, Retrieved 28th February 2010 from: http://emedicine.medscape.com/article/859316-overview Fry, J, Sandler, G, 1993, Common diseases: Their nature, prevalence and care, Radcliffe Publishing, Oxford, UK. Gelfand, S.A, 2009, Essentials of Audiology, 3rd Ed., Thieme Medical Publishers Inc., NY, USA, pp 174-176 Gelfand, S.A., 2009, Essentials of Audiology, Thieme Medical Publishers, New York, USA HARP. Case Notes Hall, J.W., 2000, Handbook of Otoacoustic emissions, Thomas Learning, Singular Publishing Group, California, USA, pg 228 Hughes, G.B, Pensak, M.L, 2007, Clinical Otology, Thieme Medical Publishing group, USA. Klein, J.O., 1994, Otitis Media, Clinical Infectious Diseases, 19(5), pp. 823832, The University of Chicago Press. Madell, J.R., Flexer, C, 2008, Pediatric Audiology: Diagnosis, Technology and Management, Thieme Medical Publishers, New York, USA, pp 77-79 NHS Choices, Otitis Media, Retrieved 28th February 2010 from: http://www.nhs.uk/Conditions/Otitis-media/Pages/Causes.aspx NHS Choices: Labyrinthitis, Retrieved 25th April 2010 from: http://www.nhs.uk/Conditions/Labyrinthitis/Pages/Symptoms.aspx O'Neill, P, 1999, Clinical review: Acute otitis media, British Medical Journal, 319: pp 833-835. Otitis media, 2002, NIDCD (National Institute on Deafness and other Communication Disorders), Bethesda Maryland, USA, Retrieved 20 th February 2010 from: http://www.nidcd.nih.gov/health/hearing/otitism.asp Pavlovcinova, G, Jakubikova, J, Hromadkova, P, Mohammed, E, 2008, Severe Acute Otitis Media in children, Bratislava Medical Journal, 109 (5), pp 204-209 Shanks, J & Shohet, J, 2009 ‘Tympanometry in clinical practice’ in Katz, J, Medwetsky, L, Burkard, R & Hood, L, (eds), Handbook of Clinical Audiology, Lippincott Williams & Wilkins, USA pp 159-185 HARP. Case Notes Stach, B.A., Ramachandran, V.S., 2008, ‘Hearing Disorders in Children’, in J.R., Madell & C. Flexer, (eds), Pediatric Audiology: Diagnosis, Technology and Management, Thieme Medical Publishers, New York, USA Stool S.E., Berg A.O.,1994, Otitis Media with Effusion in Young Children: Clinical Practice Guideline, Diane Pub Co, Darby, PA, USA Subcommittee On Management of Acute Otitis Media, Diagnosis and Management of Acute Otitis Media, Pediatrics; 113, pp 1451- 1465 WHO/CIBA Foundation Workshop, 1996, Prevention of hearing impairment from Chronic Otitis Media, London, UK, Retrieved 27th April 2010 from: http://www.who.int/pbd/deafness/en/chronic_otitis_media.pdf, pp 14-16