Pediatrics

Encephalitis

OVERVIEW: What every practitioner needs to know

Are you sure your patient has mastoiditis? What are the typical findings for this disease?

Mastoiditis is inflammation of the mastoid air cells, air-filled mucosal lined spaces within the temporal bone. Mastoiditis can be acute or chronic, based on the severity of disease and type and time-course of signs and symptoms. Acute mastoiditis is the condition most typically associated with the term "mastoiditis," and this is a complication of acute otitis media seen most often in young children. Mastoiditis usually presents with signs of inflammation in the area of the mastoid, with signs and symptoms of acute otitis media accompanied by displacement of the pinna. It is important to maintain a distinction between acute mastoiditis and chronic mastoiditis.

  1. Inflammation of the mastoid area: The mastoid is an area of the temporal bone located behind the pinna. Edema, erythema, and tenderness are evident (see Figure 1).

  2. The pinna often is displaced anteriorly, and "protrudes." The area behind the ear may be painful and doughy to palpation. Comparison with the opposite ear is often helpful (see Figure 2).

  3. Mastoiditis is often preceded or accompanied by the signs and symptoms of acute otitis media. Otalgia is often present. Otorrhea may occur if tympanic membrane perforates. Hearing may be decreased as a conductive hearing loss is expected when a middle ear effusion is present.

  4. Otoscopy can show an inflamed, bulging, red tympanic membrane, or may show otorrhea if tympanic membrane perforates. The external auditory canal may be swollen, particularly along the posterior aspect.

  5. Fever may be present from the middle ear and mastoid inflammation. High-spiking, recurrent fevers ("picket-fence fevers") may represent spread of infection to the adjacent dural sinus system, causing a lateral sinus or sigmoid sinus thrombosis.

  6. A recent review of the KIDS inpatient database for the year 2009 showed acute mastoiditis to be the most common complication of acute otitis media in children admitted with a diagnosis of otitis media. This complication was unusual, with 2.4% of children hospitalized with a diagnosis of otitis media also diagnosed with acute otitis media.

Figure 1.

Erythema behind the ear indicative of mastoiditis

Figure 2.

Protruding pinna with mastoiditis

Associated Neurologic Signs and Symptoms

While acute mastoiditis is a complication of otitis media, neurologic signs and symptoms, aside from lethargy, should suggest that another suppurative complication of otitis media has occurred. Severe headache or seizure, or focal neurologic deficits, could indicate an intracranial process such as epidural abscess or brain abscess. Facial nerve weakness can occur from inflammatory involvement of the facial nerve due to infection in the middle ear and/or mastoid. Severe lethargy and nuchal rigidity may indicate meningitis.

Distinction between acute and chronic mastoiditis

Chronic mastoiditis, also called chronic tympanomastoiditis or chronic suppurative otitis media, is an inflammatory disease of the mastoid and middle ear that often presents with chronic drainage from the ear and hearing loss. Fever, ear displacement, and severe pain is rarely seen, and chronic ear problems with drainage and hearing loss are the rule in patients with chronic mastoiditis. The drainage is usually indicative of a tympanic membrane perforation or a cholesteatoma, and the bacteriology differs from that of acute mastoiditis. The treatment strategy is different from that used for acute mastoiditis as well.

What other disease/condition shares some of these symptoms?

Acute otitis media - Acute mastoiditis develops as a complication of acute otitis media. Examination of the mastoid and periauricular areas can differentiate between simple acute otitis media or complicated otitis media with mastoiditis. There may be a continuum of signs and symptoms, as early mastoid inflammation can occur with some acute otitis media episodes, with associated mild retroauricular erythema and swelling.

Radiographic imaging, computed tomography (CT) or magnetic resonance imaging (MRI), in children with acute otitis media or chronic otitis media with effusion, often shows mastoid involvement, even though acute mastoiditis is not present. The mastoid air cell system is in functional and anatomic continuity with the middle ear, and inflammation of the middle ear is often associated with mastoid fluid or mucosal inflammation. While these "mastoid effusions" are often deemed mastoiditis on radiologic reports, acute mastoiditis is present only when these radiographic findings are present in the context of the clinical picture detailed above.

Local cellulitis of the scalp or preauricular tissues, or insect bites. Isolated inflammation or infection of the skin and scalp tissues behind the ear can mimic some signs of acute mastoiditis. Careful history taking and otoscopy can help distinguish these conditions.

Temporal bone trauma may cause periauricular swelling and opacification of the mastoid system on CT. History and examination should help exclude acute otitis media. Inflammation of the ear drum should be absent, although hemotympanum may be present.

Otitis externa is an infection of the tissues of the external auditory canal, without middle ear or mastoid inflammation. Often associated with ear canal trauma or water exposure to the ear (i.e., "swimmer's ear"), the pain can be severe and otorrhea is often present. Severe otitis externa can lead to periauricular swelling and local lymphadenopathy in front of and behind the pinna, and may simulate acute mastoiditis in some respects. While otoscopy should help exclude mastoiditis, as the tympanic membrane should be uninflamed and the middle ear free of effusion, swelling of the ear canal and presence of otorrhea may make this distinction difficult. Imaging in such cases of otitis externa, using CT, should show clear mastoid cells and middle ear space.

Unusual inflammatory processes may mimic acute mastoiditis. One such inflammatory process, Langerhan cell histiocytosis, can present with inflammation of the ear and mastoid that behaves atypically or fails to respond to appropriate treatment (see Figure 3). Biopsy may be necessary in such cases.

Figure 3.

Mastoid and postauricular involvement with Langerhan cell histiocytosis

Benign and malignant tumors may cause swelling around the ear. Benign processes such as congenital cysts, lymphatic malformations, etc. can occur around the ear and cause swelling. Malignant tumors such as rhabdomyosarcoma can also occur in this area. Middle ear inflammation is usually absent and clinical behavior distinguishes such masses from acute mastoiditis. Biopsy and/or excision is considered when clinically indicated.

What caused this disease to develop at this time?

Mastoiditis is an inflammation of the mastoid air cell system, mucosa-lined air spaces within the temporal bone that are functionally and anatomically connected with the middle ear. The anatomic connection between the middle ear and mastoid air cell system is through the additus ad antrum, the aerated system between the mastoid antrum and the superior and posterior middle ear. Mastoiditis occurs as a complication of otitis media, and likely occurs from insufficient drainage of the mastoid air cells into the middle ear. The middle ear in turn becomes inflamed when the eustachian tube does not allow appropriate drainage into the nasopharynx.

Young children, usually under 10 years of age, are more likely to develop acute otitis media and thus are likely to develop acute mastoiditis. Older children and adults who develop mastoiditis may have cholesteatoma or more chronic infection, rather than acute otitis media as a causative factor. Children who present with acute mastoiditis are usually under 2 years of age, are more likely to be boys, and often have no history of recurrent otitis media.

What laboratory studies should you request to help confirm the diagnosis? How should you interpret the results?

Acute mastoiditis is a clinical diagnosis made by history and examination with careful otoscopy. Laboratory tests can confirm the presence of acute infection, and cultures can provide information to direct antimicrobial treatment.

Peripheral white blood count (WBC) and neutrophil count - With acute mastoiditis, as with most infections, we expect elevated WBC with increased percentage of neutrophils and bands. Patients with additional local or intracranial complications of mastoidits may have greater elevations of WBC.

C-reactive protein (CRP) - CRP, a marker for acute inflammation, is elevated in cases of acute mastoiditis, but is not specific for this disease.

Cultures/gram stain of middle ear and/or mastoid contents can confirm acute mastoid infection and identify organisms to direct antimicrobial treatment. Specimens can be obtained from the middle ear with myringotomy (incision of the tympanic membrane) or tympanoscentesis (needle aspiration of the middle ear through the tympanic membrane). In those patients who present with otorrhea through a tympanic membrane perforation or a tympanostomy tube, cultures can be obtained by sampling the fluid in the external auditory canal with a swab. The cultures obtained at surgical myringotomy after sterile preparation of the ear canal are less likely to be contaminated with non-pathogens.

Myringotomy or tympanoscentesis requires experience and familiarity with middle ear anatomy to avoid risks to ossicles, facial nerve, and other structures.

Cultures and gram stain can also be obtained by needle aspiration of the retroauricular area when a subperiosteal abscess (fluid between the mastoid cortex and the temporalis muscle) is suspected. Cultures can be obtained from mastoid tissue when mastoidectomy is performed as part of the treatment for acute mastoiditis.

Lumbar puncture should be considered when meningitis is suspected. If additional complications such as epidural abscess or parenchymal brain abscess are suspected, or if focal neurologic deficits and/or papilledema are found, imaging of the brain should be performed before a lumbar puncture is undertaken.

Would imaging studies be helpful? If so, which ones?

Computed tomography (CT) of the temporal bone and brain is the gold standard for the diagnosis of acute and chronic mastoiditis. The temporal bone images will show mucosal inflammation with fluid or soft tissue in the mastoid air cells and the middle ear. We must remember that all patients with middle ear disease, even uncomplicated otitis media, will have associated mastoid inflammation (opacification) on CT scan. The diagnosis of acute mastoiditis must be made with the CT findings interpreted in the appropriate clinical context. Intravenous contrast is useful when the brain is imaged in addition to the temporal bone. Such imaging is used when associated complications are suspected, such as lateral sinus thrombophlebitis, epidural abscess, or brain abscess.

The temporal bone CT scan images will show mucosal inflammation with acute mastoiditis, but may also show erosion of the mastoid cortex, destruction of the bony septations within the mastoid air cell system (coalescent mastoiditis), or collections of fluid between the mastoid cortex and the temporalis muscle (subperiosteal abscess). See Figure 4.

Figure 4.

Subperiosteal abscess

Temporal bone CT scans are usually performed at higher resolution with thinner cuts than brain imaging (one mm sections). Axial and coronal images can provide anatomic details that can both help diagnose acute mastoiditis, rule out associated conditions and complications such as cholesteatoma, and assess the anatomic integrity of temporal bone structures such as the ossicular chain, the facial nerve, and the cochlea.

Magnetic resonance imaging (MRI) is not a first line diagnostic test for acute mastoiditis. In fact, a recent study of children undergoing MRI for reasons other than otitis media-related disease found that 21.4% of children had mastoid opacification as an incidental finding, and these incidental findings increased to over 40% in children younger than age 2 years. It can be used to evaluate intracranial complications of acute otitis media that may be suspected. MRI can be used for patient with chronic mastoiditis, cholesteatoma, or other destructive temporal bone processes to assess the integrity of the brain and dura.

While CT scans are the best test for acute mastoiditis, the timing of such studies remains debated, particularly for those patients with early or mild symptoms and signs. CT scans involve some ionizing radiation exposure as well as the need for sedation in some children. With our efforts to reduce children’s exposure to ionizing radiation and our goals to reduce the costs associated with unnecessary tests, the timing and necessity of imaging at the time of diagnosis of acute mastoiditis are worth discussing. Early imaging can confirm the diagnosis of acute mastoiditis and identify associated intracranial complications. Advocates for more selective use of imaging note that many children can be diagnosed clinically, will often improve with initial medical therapy and/or myringotomy, and can be imaged for persistent or worsening disease. Early signs of mastoid inflammation may merit aggressive medical therapy and close follow-up before imaging is performed. Severe cases that warrant prompt surgical therapy as well as medical therapy, and those cases where spread of infection or complications are suspected, should have immediate CT scanning to help plan treatment.

If you are able to confirm that the patient has mastoiditis, what treatment should be initiated?

Patients with acute mastoiditis require medical therapy for complicated otitis media, and they may require prompt surgical therapy. Most children with signs and symptoms of acute mastoiditis are admitted for parenteral antibiotic therapy, directed against the usual organisms that cause acute otitis media: Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. Treatment should include coverage against resistant strains of pneumococcus as well as Streptococcus species that have been seen in complications of acute otitis media. If otorrhea is present, cultures and gram stains can be obtained to direct antibiotic therapy.

Acute mastoiditis may require surgical intervention. Surgery may include a myringotomy with or without a tympanostomy tube to drain the middle ear space and provide cultures to direct treatment, needle aspiration of the postauricular space if a subperiosteal abscess is suspected, or mastoidectomy to remove infected air cells and drain pockets of infection.

Chronic mastoiditis is usually manifested by chronic otorrhea, often in the absence of systemic signs or symptoms. The treatment of chronic mastoid inflammation involves medical therapy, including systemic antibiotics and ototopical antimicrobials, serial ear cleansing by a specialist, and surgery directed at removing infected mastoid air cells, closing the middle ear space by repairing the tympanic membrane when appropriate, and removing cholesteatoma when present. The bacteriology of chronic mastoid infections often includes gram-negative organisms such as Pseudomonas aeruginosa.

Acute mastoiditis may require specialty consultation by otolaryngology, particularly when surgical drainage is indicated. Neurosurgical consultation should be considered when intracranial spread of infection is suspected.

What are the adverse effects associated with each treatment option?

The adverse effects of antibiotic therapy include allergic reaction, and gastrointestinal side effects. Intravenous administration of antibiotics may cause local problems at the site of intravenous access.

Myringotomy has possible complications, including persistent perforation or damage to middle ear structures. Mastoidectomy can be complicated by damage to adjacent structures including the ossicular chain, the facial nerve, and dura, and the sigmoid sinus. Such surgical complications are, indeed, rare.

What are the possible outcomes of mastoiditis?

The prognosis for uncomplicated acute mastoiditis is quite favorable, with prompt recovery expected for all who are diagnosed and treated appropriately. Even when mastoidectomy is required in addition to antibiotic therapy, recovery is expected within a few days. Additional complications of mastoiditis and acute otitis media can occur in some cases, some of which may lead to adverse neurologic outcomes and need for more prolonged medical therapy and morbid surgical therapy as well.

What causes this disease and how frequent is it?

Mastoiditis is a complication of otitis media. The frequency varies from series to series but an incidence of 1.2 to 3.8 cases per 100,000 person-years in the United States, Canada, and Europe. Mastoiditis incidence has decreased since the routine use of antibiotics for ear infections. While some authors have hypothesized that the incidence of mastoiditis has increased, perhaps because of the emergence of antibiotic-resistant bacterial organisms and trends toward observing otitis media without immediate antibiotic use, these increases have not been well documented. If such an increase is indeed occurring, it is small and perhaps not significant when dealing with a rare complication of a common illness. One recent study noted an initial decrease in acute mastoiditis incidence after the initial widespread immunization of infants with Prevnar, but these rates appeared to increase to pre-vaccination levels several years later, likely due to infection with bacterial strains not included in the early vaccine.

What are the organisms causing mastoiditis?

The most common organism associated with acute mastoiditis is Streptococcus pneumoniae, and other organisms include Streptococcus pyogenes, Haemophilus influenzae, Staphylococcus aureus, and Moraxella catarrhalis. Chronic mastoiditis is often caused by gram-negative organisms such as Pseudomonas aeruginosa as well as anaerobes.

Cultures of mastoid specimens may fail to grow organisms up to 40% of the time, often because antibiotics are promptly administered before surgical cultures can be collected.

Streptococcus pneumoniae serotype 19A, a multi-drug resistant strain, has emerged as the dominant causative organism in acute mastoiditis in young children. This has replaced serotype 19F, with the routine use of the 7-valent pneumococcal conjugate vaccine that contains serotypes 5, 6B, 9V, 14, 18C, 23 F, and 19F.

What complications might you expect from the disease or treatment of the disease?

The complications of acute mastoiditis and acute otitis media occur from spread of infection within or outside the temporal bone, causing intratemporal or intracranial complications. Management of these complications include antibiotic therapy as well as otolaryngologic and/or neurosurgical surgical procedures for drainage or removal of infected tissues.

The intratemporal complications of acute mastoiditis include:

1. Hearing loss - Fluid in the middle ear causes conductive hearing loss that should be a temporary condition that resolves with resolution of infection and middle ear fluid. In rare cases, labyrinthitis with inflammation of the cochlea can lead to permanent sensorineural hearing loss. Labrynthitis has symptoms of vertigo and hearing loss, and nystagmus and nausea/vomiting may be present.

2. Facial paralysis - Paralysis of the seventh cranial nerve can occur from middle ear or mastoid inflammation. The facial nerve runs through the internal auditory canal, the labrynthine and tympanic portions of the temporal bone, and the mastoid bone. Inflammation of the middle ear and/or mastoid during acute infection may cause motor weakness on the affected side of the face. While idiopathic facial paralysis (Bell's palsy) is common in adults, children with an acute onset facial palsy must be examined for the presence of middle ear disease such as otitis media or cholesteatoma.

Treatment of facial paralysis from acute otitis media consists of antibiotics, often parenteral, as well as myringotomy for drainage and culture. Steroids are often used in such cases but the efficacy is not proven. Full recovery of facial nerve function is the rule, and when the rare case of residual weakness is seen, evaulation for another etiology of facial nerve palsy (including tumors and Lyme disease) is prudent.

Chronic mastoiditis with or without cholesteatoma may cause facial paralysis, and surgical exploration (after appropriate imaging) is necessary in such cases to decompress the nerve and treat cholesteatoma or other lesions that may be causing facial nerve injury.

3. Coalescent mastoiditis - Acute mastoiditis may cause erosion of the septated mastoid air cell system, and may create a large cavity containing infected mucosa and purulent debris. Mastoidectomy is often necessary to drain these cases, especially if antibiotic therapy and myringotomy have not been successful.

4. Subperiosteal abscess - Acute mastoiditis may allow infectious spread through the mastoid cortex to the space between the cortex and the periosteum/temporalis muscle, creating a fluid collection. Clinically, fullness of the supra- and retroauricular tissues is seen as well as redness and edema. Outward and downward pinna displacement seen in mastoiditis may be more accentuated with a subperiosteal abscess. Fluctuance may be limited on palpation/examination as the collection is deep to the temporalis muscle. Drainage of these collections can be performed with needle aspiration or incision at the time of myringotomy, but often a subperiosteal abscess is drained at the time of mastoidectomy through the same postauricular incision.

5. Petrositis - Extension of mastoid and middle ear inflammation into the deeper aerated portions of the temporal bone ("petrous apex') is rare. Infectious extension into the more medial portions of the base of skull can occur with chronic or acute mastoid disease. Inflammation around the trigeminal ganglion and the abducens canal can lead to a symptoms complex of deep facial or retroorbital pain and lateral gaze paralysis, sometimes known as Gradenigo syndrome. Long term antibiotic therapy is often needed as even extended mastoidectomy approaches will not drain or remove the areas of skull base infection.

6. Bezold abscess - Acute mastoiditis can be complicated by spread of infection from aerated mastoid cells into the upper neck, with presentation as a neck abscess. Spread of infection occurs from the cells of the mastoid tip down along the adjacent sternomastoid and digastric neck muscles. Neck swelling with associated local ear symptoms are noted. Surgical drainage of the neck collection along with mastoidectomy and antibiotic therapy is necessary for this rare complication.

The intracranial complications of mastoiditis include:

1. Meningitis - acute meningitis can occur with acute otitis media with or without mastoiditis. Children with meningeal signs or symptoms associated with acute otitis media need lumbar puncture for prompt diagnosis. Hematogenous spread during an episode of acute otitis media can cause seeding of the meninges with bacterial pathogens and direct spread of middle ear or mastoid infection can occur through preformed channels in the temporal bone (Hyrtl's fissures). Intravenous antibiotics are used, directing antibiotic choice with CSF cultures and middle ear cultures if a myringotomy is performed, using antibiotic with central nervous system penetration.

2. Epidural abscess - Collection of purulent material between the cranium and dura can occur with acute mastoid infection. Diagnosis is made by CT or MRI and treatment consists of mastoidectomy to open the mastoid air cells and drain the collection of purulence. Formal craniotomy is usually not needed as the epidural collection is usually adjacent to the affected mastoid cells.

Subdural empyema is less common and presents with high fevers and even seizures and altered mental status. Neurosurgical drainage is often necessary in addition to antibiotic therapy.

3. Brain abscess - Brain abscesses from otitis media can present dramatically or indolently. Symptoms of increased intracranial pressure include headache, vomiting, altered mental status, papilledema. Focal neurologic signs and deficits may occur as well. Neurosurgical consultation is needed for consideration of drainage of large abscesses. Some small brain abscesses are treated medically.

4. Lateral sinus thrombophlebitis - The lateral and sigmoid dural sinuses are adjacent to the mastoid air cell system, and mastoid infection can cause septic thrombosis of these structures. High spiking (picket fence) fevers can be seen, and in some cases headache and papilledema are seen ("otitic hydrocephalus"). MRI with MR angiography/venography can assess lateral/sigmoid sinus patency as well as the presence of surrounding inflammation. Broad spectrum intravenous antibiotics are needed, and if acute mastoid inflammation is evident, mastoidectomy is performed.

The roles of dural sinus surgical decompression, clot removal, and anticoagulation remain unproven and debated. Otitic hydrocephalus can be seen as late sequela of otitis media and/or mastoiditis weeks after acute infection has resolved. Otitic hydrocephalus can be treated with medications to reduce CSF pressure and serial lumbar punctures.

How can mastoiditis be prevented?

It may be very difficult to prevent most cases of acute mastoiditis as it usually occurs quickly as a complication of a disease that is very common in children, acute otitis media. There are a few risk factors that have been identified for progression from acute otitis media to mastoiditis. Young children, particularly those under 2 years of age, are at increased risk of complicated mastoiditis compared to older children.

Guidelines for treatment of acute otitis media have recommended antibiotic therapy for such young children with acute otitis media at the time of diagnosis, rather than selecting an observation period before treatment. While it has been suggested that observation of children without antibiotic therapy for acute otitis media may increase the rate of complications such as mastoiditis, this does not appear to be the case. Common risk factors for acute otitis media include group child care attendance and tobacco exposure.

Prevention of acute mastoiditis could coincide with strategies to prevent acute otitis media in at risk children. Vaccines against pneumococcus and influenza can decrease the frequency of acute otitis media. Unfortunately, even with a decrease in otitis media in young children, a decrease in the incidence of acute mastoiditis has not been demonstrated. Prevnar 13 is now administered to virtually all young children in the United States. Prior to the widespread use of this vaccine, the pneumococcus serotype 19F was the most common cause of acute mastoiditis. After widespread use of Prevnar 7, serotype 19A became an increasing cause of acute mastoiditis cases. Prevnar 13 may change the bacteriology of these complications of acute otitis media, since serotype 19A is one of the antigens included.

While tympanostomy tube placement appears to reduce the frequency of recurrent acute otitis media in at risk children, the benefits of the surgery are modest and the support in the medical literature is not robust. Similarly, long-term antibiotic prophylaxis for children with recurrent acute otitis media provides only a small reduction in the number of otitis media episodes and only during the period of time when the antibiotics are administered. The risks of antibiotic adverse reactions and the potential for bacterial resistance make antibiotic prophylaxis of recurrent otitis media unwise.

What is the evidence?

Bilavsky, E, Yarden-Bilavsky, H, Samra, Z, Amir, J, Nussinovitch, M. "Clinical, laboratory, and microbiological differences between children with simple or complicated mastoiditis". Int J Pediatr Otorhinolaryngol. vol. 73. 2009. pp. 1270-3.

(A large retrospective review of 308 children with acute mastoiditis describing clinical, laboratory and microbiological differences in children with simple and complicated mastoiditis.)

Chesney, J, Black, A, Choo, D. "What is the best practice for acute mastoiditis in children?". Laryngoscope. vol. 124. 2013. pp. 1057-9.

(A brief review of evidence with an algorithm that outlines progression from medical treatment to surgical interventions.)

Geva, A, Oestreicher-Kedem, Y, Fishman, G, Landsberg, R, DeRowe, A. "Conservative management of acute mastoiditis in children". Int J Pediatr Otorhinolaryngol. vol. 72. 2008. pp. 629-34.

(A retrospective review of clinical outcomes of 144 children treated with intravenous antibiotics with or without myringotomy. Myringotomy was not always necessary, as medical treatment was effective in almost two thirds of cases without myringotomy.)

Go, C, Bernstein, JM, de Jong, AL, Sulek, M, Friedman, EM. "Intracranial complications of acute mastoiditis". Int J Pediatr Otorhinolaryngol. vol. 52. 2000. pp. 143-8.

(A retrospective review of 118 children with acute mastoiditis describing the incidence, risk factors, and pathology organism involved in intracranial complication.)

Halgrimson, WR, Chan, KH, Abzug, MJ, Perkins, JN, Carosone-Link, P, Simoes, EAF. "Incidence of acute mastoiditis in Colorado children in the pneumococcal conjugate vaccine era". Pediatr Infect Dis J. vol. 33. 2014. pp. 453-7.

(These authors demonstrate that the initial decrease in acute mastoiditis seen in Colorado with the introduction of the pneumococcal conjugate vaccine was not sustained.)

Lavin, JM, Rusher, T, Shah, RK. "Complications of pediatric otitis media". Otolaryngol Head Neck Surg. vol. 154. 2016. pp. 366-7.

(Complications of otitis media are rare, and acute mastoiditis is the most frequent of these complications in hospitalized children.)

Luntz, M, Bartal, K, Brodsky, A, Shihada, R. "Acute mastoiditis: the role of imaging for identifying intracranial complications". Laryngoscope. vol. 122. 2012. pp. 2813-7.

(These authors advocate routine imaging on presentation with clinical signs of acute mastoiditis, as 14% of their patients had clinically unsuspected intracranial complications found on contrast-enhanced CT scan.)

Maaike, T, Van den Aardweg, A, Rovers, MM, de Ru, JA, Albers, FWJ, Schilder, AGM. "A systematic review of diagnostic criteria for acute mastoiditis in children". Otol Neurotol. vol. 29. 2008. pp. 751-7.

(The study constitutes a systematic retrospective review of the literature on acute mastoiditis in children including 65 articles, mostly retrospective data and case reports. The study includes diagnostic strategies, laboratory data, imaging, microbiology, and complication diagnosis. These authors found variations in the diagnostic criteria for acute mastoiditis that affects who we should interpret the relevant literature.)

Moore, JA, Wei, JL, Smith, HJ, Mayo, MS. "Treatment of pediatric suppurative mastoiditis; is peripheral inserted central catheter (PICC) antibiotic therapy necessary?". Otolaryngol Head Neck Surg. vol. 135. 2006. pp. 106-10.

(Authors compared outcomes of children treated with oral antibiotic therapy after mastoidectomy with those treated with prolonged intravenous antibiotics after surgery for mastoiditis. Intravenous therapy did not improve outcomes despite much greater cost. These were surgical patients who had presumably severe acute mastoid infection, but we cannot extrapolate these conclusions to those with acute mastoiditis treated medically without mastoidectomy.)

Ongkasuwan, J, Valdez, TA, Hulten, KG, Mason, EO, Kaplan, SL. "Pneumococcal mastoiditis in children and the emergence of multidrug-resistant serotype 19A Isolates". Pediatrics. vol. 122. 2008. pp. 34-9.

(This retrospective review analyzes cases of acute mastoiditis to evaluate the changes in microbiology since the institution of the heptavalent pneumococcal vaccine, and displays the prominent role of the 19A serotype.)

Singh, S, Rettiganti, MR, Qin, C, Kurova, M, Hegdi, SV. "Incidental mastoid opacification in children on MRI". Pediatr Radiol. 2016 Feb 25.

(Mastoid opacification on an MRI does not equal acute mastoiditis!)

Tamir, S, Schwartz, Y, Peleg, U, Perez, R, Sichel, J. "Acute mastoiditis in children: is computed tomography always necessary". Ann Otol Rhinol Laryngol. vol. 118. 2009. pp. 565-68.

(The majority of the children with clinical diagnosis of acute mastoiditis reported here did not require CT scan.)

Ongoing controversies regarding etiology, diagnosis, treatment

When is surgery needed?

Most cases will respond to medical therapy alone, but a simple surgical intervention, myringotomy, can provide culture information to direct medical therapy and afford drainage of the middle ear that may allow prompt resolution of symptoms. The role of mastoidectomy is debated, as mastoidectomy can allow drainage by removing infected cells. Antibiotic treatment may be as effective in some cases of mastoiditis. Indications for mastoidectomy include subperiosteal abscess or coalescent mastoiditis, poor response to medical therapy, or signs and symptoms of other infectious complications.

Duration of treatment and need for parenteral antibiotics:

The duration of antibiotic therapy provided is not uniform, nor are recommendations for intravenous versus oral systemic therapy. Several weeks of oral antibiotics often follow initial treatment with several days of intravenous medications. Longer duration of antibiotics and need for intravenous medications may be indicated when suppurative intracranial complications have occurred with acute mastoiditis or when resistant organisms have been isolated or are suspected.

When should imaging be performed?

The timing of CT scans or MRIs should be based on the severity of signs and symptoms, suspicion of associated intracranial infection, the possible need for surgical intervention, and the response to (or lack of response) to medical therapy.

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