Acute mastoiditis (AM) develops as a complication of acute otitis media (AOM) when infection spreads beyond the middle ear and persists within the mastoid bone. Children younger than age 2 years are most commonly affected, although complications may be seen more frequently in older age groups.1,2 Given the proximity of the mastoid bone to the central nervous system, timely recognition and treatment of mastoiditis is critical.
To better understand the pathophysiology of mastoiditis and its complications, the anatomy of the middle ear and mastoid is briefly reviewed (Figure 1). A small medial connection unites the mastoid air cells to the middle ear, which is then drained by the eustachian tube. Multiple structures, including the sigmoid sinus, seventh cranial nerve, carotid artery, and brain parenchyma, lie adjacent to the mastoid air cells. AOM causes inflammation and fluid build-up within the middle ear. This fluid frequently spreads to the mastoid as well. In most cases, the inflammation and fluid resolve with or without antimicrobial treatment of AOM. However, in rare instances AM can result from persistent inflammation and infection.
Anatomy of the mastoid. The mastoid sits between the middle ear and multiple important structures, including the carotid artery, the seventh cranial nerve, and the sigmoid sinus. The eustachian tube drains the middle ear, and a small connection called the aditus ad antrum unites the middle ear and mastoid.
The incidence of AM is relatively rare, with approximately 1.6 episodes per 100,000 person-years in the United States.3 The number of episodes secondary to pneumococcal disease appears to be in decline since the introduction of population vaccination with the 13-valent pneumococcal conjugate vaccine in 2010.4–6 In 2013, the American Academy of Pediatrics proposed an evidence-based clinical practice guideline that limited antibiotic use in AOM based on age, severity, duration of symptoms, and presence of otorrhea.7 The long-term influence of these recent changes in antibiotic prescribing practices and pneumococcal vaccination on the incidence of AM is yet to be determined.
An 11-month-old fully vaccinated infant presented to the otolaryngology (ie, ears, nose, and throat [ENT]) clinic with a 1-week history of left otitis media and persistent fever despite antimicrobial treatment. The patient was seen by her pediatrician 1 week prior to presentation and was initially treated with cefdinir, but due to vomiting she was switched to azithromycin after 3 days. Because of persistent fever, she was then switched to amoxicillin/clavulanic acid 2 days later. Two days prior to presentation at the ENT clinic, drainage was noted from the left ear and the parents reported noticing protrusion of the auricle. In the ENT clinic, a review of systems was significant for decreased appetite and whimpering during sleep. Of note, the patient had otitis media (parents were unsure in which ear) about 1 month prior that was treated with amoxicillin/clavulanic acid.
The patient's medical and surgical histories were otherwise unremarkable, with no developmental concerns. One of her sisters had frequent ear infections. The patient did not attend daycare, and there were no smokers at home.
Her examination was notable for symmetric facies except for the left pinna, which was forward with postauricular edema without palpable fluctuance. The right pinna and ear canal were normal. The right tympanic membrane was opaque, erythematous, and bulging. The left external auditory canal was filled with copious purulent material that was cleaned under the microscope. The left tympanic membrane was thickened with erythema. With a clinical presentation concerning for acute mastoiditis, she was admitted for intravenous (IV) antibiotics. Basic laboratory studies noted a white blood cell count of 18,200/mcL. She was administered IV ceftriaxone.
A computed tomography (CT) scan of temporal bone with contrast was performed to evaluate for potential complications. This study confirmed a left postauricular subperiosteal abscess (Figure 2). After discussion with the parents regarding treatment options, the patient was taken to the operating room for incision and drainage of the abscess with myringotomy tube placement. She was continued on IV ceftriaxone and remained afebrile during her hospitalization. Bacterial cultures were taken intraoperatively and later grew penicillin-sensitive Streptococcus pneumoniae. Specific serotype testing was not performed. She was discharged home on postoperative day 2 on oral levofloxacin (due to her previous intolerance of other medications). She has done well since discharge.
Subperiosteal abscess. Computed tomography of the temporal bone with contrast showing left subperiosteal abscess measuring 2.15 cm in diameter.
Three bacteria cause the majority of cases of AM disease: S. pneumoniae, S. pyogenes, and Staphylococcus aureus.8 Isolation of a potential pathogen occurs in approximately 36% to 64% of episodes.6,9 Tympanocentesis improves the rate of pathogen detection compared to ear canal swab and decreases the likelihood of identifying a contaminant.
S. pneumoniae is the most common cause of pediatric AM.2,6,8,9 Prior to the introduction of pneumococcal vaccination, serotype 19F accounted for about 50% of all pneumococcal AM.10 In 2000, the heptavalent pneumococcal conjugate vaccine, which contained the predominant serotypes in North America, including 19F, was introduced. This resulted in a near complete resolution of disease caused by the 7 vaccine serotypes, but there was minimal change in the overall incidence of pneumococcal AM due to rise in episodes secondary to nonvaccine pneumococcal serotypes, especially serotype 19A.10 Early reports after the 2010 introduction of a 13-valent pneumococcal vaccine, which includes serotype 19A, suggest a significant decrease in pneumococcal AM.4–6
AM frequently presents with fever, otalgia, retroauricular tenderness, edema, and erythema with later progression to proptosis of the auricle. Tympanic membranes have the appearance of AOM and otorrhea can sometimes be seen. A recent history of AOM may or may not be present.1 Children older than age 2 years may also present with a longer duration of symptoms.2
Complications of AM can arise in 7% to 16% of cases.8 These may include both extracranial and intracranial findings. Subperiosteal abscess formation is the most common complication of AM and occurs on average in 58% of cases.8 Other adjacent structures may also be involved, such as the inner ear, neck muscles, the facial nerve, and the cranial bones. Abscess formation within the sternocleidomastoid muscle is a rare and unique complication of mastoiditis; it is termed a Bezold abscess.8 Facial nerve palsy may result due to inflammation of the nerve as it passes through the petrous portion of the temporal bone. If the apex of the petrous bone becomes infected, Gradenigo syndrome results with unilateral periorbital pain due to trigeminal nerve inflammation, sixth nerve palsy, and otorrhea.8 Osteomyelitis may occur in other cranial bones as well. Additionally, suppurative labyrinthitis can result in hearing loss that may be permanent.
Infection may also spread to intracranial structures, including the sigmoid sinus, meninges, dura, and brain parenchyma.11 Venous thrombosis occurs if inflammation spreads medially, as only a thin bone separates the mastoid from the sigmoid sinus. Meningitis can also occur. Abscesses can be found in the epidural and subdural spaces, and the temporal lobe and cerebellum are the most common sites of intraparenchymal disease.8
AM is a clinical diagnosis and imaging is not always needed. Uncomplicated AM, AOM, and asymptomatic middle ear effusions will look identical on CT imaging, with all showing fluid in the mastoid. With the renewed focus on reduction of radiation in the pediatric population, data suggest that CT imaging in pediatric AM should be obtained in patients with signs or symptoms suggesting possible complications, including neurologic signs, concern for cholesteatoma, severe clinical presentation, failure to improve or worsening with conservative treatment, or suspected intracranial complication. Contrast-enhanced CT will allow for evaluation of abscess formation, bony destruction, and extension into the central nervous system. Magnetic resonance imaging may be better if venous thrombosis is suspected. If meningeal signs are present, a full set of laboratory tests with cerebrospinal fluid sampling is warranted after imaging. Plain radiographs are not indicated in the diagnostic approach of AM.
When possible, middle ear fluid cultures should be obtained in cases of AM to help direct antibiotic therapy. Cultures from tympanocentesis, abscess drainage (when present), or surgical specimens are the highest yielding. External ear canal samples frequently return contaminants, so results should be interpreted carefully.
Prompt initiation of parenteral antibiotics that cover the major bacterial pathogens for AM is recommended. A variety of empiric antimicrobial regimens can be used. Some experts recommend vancomycin alone; however, past studies indicate that ceftriaxone alone or a combination of beta-lactam/beta-lactamase inhibitor agents are the most commonly used regimens.8,12,13 Recent antimicrobial use, immunization status, and knowledge of local resistance patterns can help direct initial choice of therapy. If culture results are available, antibiotics should be tailored accordingly. Transition to oral antibiotics can occur once clinical improvement is noted. A 4-week antibiotic course, including initial IV therapy, is typical.8
In the past, surgical treatment of AM consisted of routine cortical mastoidectomy. However, more recently conservative measures have been successfully used, including treatment with IV antibiotics alone, or IV antibiotics with myringotomy with or without tube placement.12,14,15 Geva et al.12 and Groth et al.2 found that myringotomy may be required more frequently for younger children. Older patients, who may present with a longer duration of symptoms prior to treatment, have a greater need for mastoidectomy.2
Similarly, subperiosteal abscess has historically required a mastoidectomy, but incision and drainage or needle aspiration can now be considered.13,16 Groth et al.2 found that younger patients are more likely to have a subperiosteal abscess drained than older patients.
If a more conservative approach is taken, the patient should be monitored for signs and symptoms of clinical worsening. If there is concern for treatment failure, additional imaging and mastoidectomy should be considered.
Acute mastoiditis remains a rare complication of acute otitis media. Diagnosis can be made on a clinical basis; however, a CT scan of the temporal bone with contrast is recommended to evaluate for complications. Conservative management with IV antibiotics alone or IV antibiotics with myringotomy with or without tube placement has been shown to be effective. Transition to oral antibiotics can occur when the patient has achieved clinical improvement.
- Thompson P, Gilbert R, Long P, Saxena S, Sharland M, Wong I. Effect of antibiotics for otitis media on mastoiditis in children: a retrospective cohort study using the United Kingdom General Practice Research Database. Pediatrics. 2009;123(2):424–430. doi:10.1542/peds.2007-3349 [CrossRef]
- Groth A, Enoksson F, Hulcrantz M, Stalfors J, Stenfeldt K, Hermansson A. Acute mastoiditis in children aged 0–16 years—a national study of 678 cases in Sweden comparing different age groups. Int J Pediatr Otorhinolaryngol. 2012;76(10):1494–1500. doi:10.1016/j.ijporl.2012.07.002 [CrossRef]
- Pritchett C, Thorne M. Incidence of pediatric acute mastoiditis: 1997–2006. Arch Otolaryngol Head Neck Surg. 2012;138(5):451–455. doi:10.1001/archoto.2012.269 [CrossRef]
- Kaplan S, Center K, Barson W, et al. Multicenter surveillance of Streptococcus pneumoniae isolates from middle ear and mastoid cultures in the 13-valent pneumococcal conjugate vaccine era. Clin Infect Dis. 2015;60(9):1339–1345.
- Ben-Shimol S, Givon-Lavi N, Leibovitz E, Raiz S, Greenberg D, Dagan R. Near-elimination of otitis media caused by 13-valent pneumococcal conjugate vaccine (PCV) serotypes in southern Israel shortly after sequential introduction of 7-valent/13-valent PCV. Clin Infect Dis. 2014;59(12):1724–1732. doi:10.1093/cid/ciu683 [CrossRef]
- Tamir S, Roth Y, Dalal I, Goldfarb A, Marom T. Acute mastoiditis in the pneumococcal conjugate vaccine era. Clin Vaccine Immunol. 2014;21(8):1189–1191. doi:10.1128/CVI.00289-14 [CrossRef]
- Lieberthal A, Carroll A, Chonmaitree T, et al. The diagnosis and management of acute otitis media. Pediatrics. 2013;131:e964–999. doi:10.1542/peds.2012-3488 [CrossRef]
- Wald E, Conway J. Mastoiditis. In: Long SS, Pickering LK, Prober CG, eds. Principles and Practice of Pediatric Infectious Diseases. 4th ed. Philadelphia, PA: Elsevier Saunders; 2012:222–227.
- Gliklich R, Eavey R, Iannuzzi R, Camacho A. A contemporary analysis of acute mastoiditis. Arch Otolaryngol Head Neck Surg. 1996;122(2):135–139. doi:10.1001/archotol.1996.01890140023006 [CrossRef]
- Ongkasuwan J, Vladez T, Hulten K, Mason E Jr, Kaplan S. Pneumococcal mastoiditis in children and the emergence of multidrug-resistant serotype 19A isolates. Pediatrics. 2008;122(1):34–39. doi:10.1542/peds.2007-2703 [CrossRef]
- Go C, Bernstein J, de Jong A, Sulek M, Friedman E. Intracranial complications of acute mastoiditis. Int J Pediatr Otorhinolaryngol. 2000;52(2):143–148. doi:10.1016/S0165-5876(00)00283-4 [CrossRef]
- Geva A, Oestreicher-Kedem Y, Fishman G, Landsberg R, DeRowe A. Conservative management of acute mastoiditis in children. Int J Pediatr Otorhinolaryngol. 2008;72(5):629–634. doi:10.1016/j.ijporl.2008.01.013 [CrossRef]
- Bakhos D, Trijolet J, Moriniere S, Pondaven S, Al Zahrani M, Lescanne E. Conservative management of acute mastoiditis in children. Arch Otolaryngol Head Neck Surg. 2011;137(4):346–350. doi:10.1001/archoto.2011.29 [CrossRef]
- Chesney J, Black A, Choo D. What is the best practice for acute mastoiditis in children?Laryngoscope. 2014;124(5):1057–1058. doi:10.1002/lary.24306 [CrossRef]
- Psarommatis I, Voudouris C, Douros K, Giannakopoulos P, Bairamis T, Carabinos C. Algorithmic management of pediatric acute mastoiditis. Int J Pediatr Otorhinolaryngol. 2012;76(6):791–796. doi:10.1016/j.ijporl.2012.02.042 [CrossRef]
- Psarommatic I, Giannakopoulos P, Theodorou E, Voudouris C, Carabinos C, Tsakanikos M. Mastoid subperiosteal abscess in children: drainage or mastoidectomy?J Laryngol Otol. 2012;126(12):1204–1208. doi:10.1017/S0022215112002332 [CrossRef]