ENT · Infectious Disease
The facts most likely to be tested
Mastoiditis is a suppurative infection of the mastoid air cells that typically arises as a complication of acute otitis media.
The most common causative pathogen in acute mastoiditis is Streptococcus pneumoniae.
Physical examination reveals postauricular erythema, tenderness, and swelling with displacement of the auricle inferiorly and anteriorly.
The classic otoscopic finding is an erythematous, bulging tympanic membrane often associated with middle ear effusion.
CT scan of the temporal bone with contrast is the diagnostic imaging modality of choice to confirm the diagnosis and evaluate for coalescent mastoiditis or intracranial extension.
Initial management requires IV antibiotics with broad-spectrum coverage and myringotomy for middle ear fluid drainage and culture.
Mastoidectomy is indicated for patients who fail to respond to medical therapy or who present with intracranial complications such as brain abscess or meningitis.
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A 4-year-old boy is brought to the emergency department by his parents due to persistent ear pain and fever for 5 days despite treatment with oral amoxicillin. On physical exam, the child appears ill and has postauricular erythema, fluctuance, and tenderness. The pinna is displaced inferiorly and anteriorly. Otoscopy reveals a bulging, opaque tympanic membrane with limited mobility. The child is febrile and tachycardic.
What is the most appropriate next step in management?
CT scan of the temporal bone with contrast
The patient presents with classic signs of mastoiditis; imaging is required to confirm the diagnosis and assess for complications like abscess formation before proceeding to surgical intervention.
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Etiology / Epidemiology
Usually a complication of acute otitis media (AOM) in children. Streptococcus pneumoniae is the most common pathogen.
Clinical Manifestations
Postauricular pain, fever, and mastoid tenderness with erythema and edema. Classic protrusion of the auricle.
Diagnosis
CT scan of the temporal bone is the gold standard. Look for coalescence of mastoid air cells.
Treatment
IV Vancomycin or Ceftriaxone plus myringotomy for drainage. Avoid delayed surgical consultation.
Prognosis
Potential for intracranial extension including meningitis or brain abscess. Requires urgent ENT referral.
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Epidemiology & Etiology
Primarily affects children following inadequately treated or recurrent AOM. Pathogens mirror AOM, with Streptococcus pneumoniae, Streptococcus pyogenes, and Staphylococcus aureus being most prevalent. Incidence has decreased significantly due to the pneumococcal conjugate vaccine.
Pertinent Anatomy
The mastoid process is a porous, air-filled bone located posterior to the middle ear. Direct communication between the middle ear and mastoid air cells allows for rapid spread of infection. The tegmen mastoideum separates the mastoid from the middle cranial fossa.
Pathophysiology
Infection begins as mucosal inflammation in the middle ear, leading to purulent exudate accumulation. Increased pressure causes osteitis and demineralization of the bony septa within the mastoid process. This results in the formation of a coalescent abscess, which can breach the cortex to form a subperiosteal abscess.
Clinical Manifestations
Patients present with deep, boring ear pain and fever. Physical exam reveals postauricular erythema, swelling, and tenderness, often with downward and outward displacement of the pinna. Red flags include cranial nerve palsies, nuchal rigidity, or altered mental status indicating intracranial extension.
Diagnosis
Clinical diagnosis is supported by imaging. CT scan of the temporal bone with contrast is the gold standard to confirm coalescence of mastoid air cells and identify abscess formation. MRI is reserved for suspected intracranial complications.
Treatment
Initial management requires IV Vancomycin or Ceftriaxone to cover resistant organisms. Myringotomy with or without tube placement is essential for culture and drainage. Failure to improve within 24-48 hours mandates mastoidectomy.
Prognosis
Early intervention usually results in full recovery. Complications include osteomyelitis, facial nerve palsy, and sigmoid sinus thrombosis. Urgent ENT consultation is mandatory to prevent permanent morbidity.
Differential Diagnosis
Otitis Externa: pain with tragal manipulation
Auricular Cellulitis: no middle ear involvement
Parotitis: swelling anterior to the ear
Lymphadenitis: discrete, mobile nodes
Cholesteatoma: chronic painless otorrhea