Presented by Maria Pak, MD
An 11-year-old boy with a PMH of asthma and allergic rhinitis, presents to ED with the chief complaint of right ear pain with drainage and a fever. Approximately five days prior to being seen in the ED, the patient had a runny nose and nasal congestion. These symptoms eventually resolved. However, for the past 2 days, he has been having watery discharge from his right ear, decreased appetite, ear pain, general malaise and subjective fevers. The discharge worsened on the morning of admission, and his mother felt that he was more tired and not really acting like he normally does (eg more fatigued, not eating right, not as active). No nausea/vomiting, headaches, neck stiffness, or changes in sensorium.
PMH: asthma, allergic rhinitis, otitis media, eczema
PSH: (Any?) none
FH: sickle cell trait, diabetes, cervical cancer
SH: lives primarily with mother and 3 siblings, and 1 nephew
Meds: albuterol prn, flovent prn, nasonex, loratadine prn
Vitals: T 37.1, P130, RR28, BP 121/85, Sat?
Gen: The child is awake, alert, answers questions appropriately and cooperating with the examination. He is lying on the stretcher, drowsy but arousable. Appears to be well-nourished male in no acute distress.
HEENT: Normocephalic, atraumatic. The neck is supple, with full range of motion and no adenopathy. The pupils are equal, round, and reactive to light, external structures of the eyes are normal. Examination of the ears shows an apparent outward displacement of the pinna of the right ear, with tenderness to palpation over the mastoid area on the right. There is clear fluid coming out of the right ear. The tympanic membrane on the right is intact, clear and gray, but appears dull. The tympanic membrane on the left appears normal. Mucus membranes are moist, but lips are dry.
CV: S1,S2, tachycardic, regular, no murmurs/rubs/gallops
Resp: CTAB, no wheezing/ronchi/rales
Abd: Nontender, nondistended, soft with no organomegaly/masses
Msk: FROM x 4,no tenderness bruising or swelling
Neuro: CN exam: EOMI, patient can close eyes/shrug shoulders/turn head against resistance, sensation intact on both sides of face, visual fields intact, no hearing loss in wither ear. Strength 5/5 in all extremeties. Patient oriented to person, time, and place. Gait is normal
CT: complete opacifaction of right mastoid air cells, middle ear and external auditory canal no evidence of bony destruction or remodeling, opacification of right external canal, lymphoid hypertrophy of adenoids
CBC: wbc 11.1 (53% neutrophils), Hgb 13, plt 290.
Course in the ED
Patient was bloused with 20cc/kg of normal saline. ENT was consulted, the on call resident recommended Ciprodex ear drops and parenteral clindamycin and ceftriaxone. He was initially admitted to the PICU due to possible sinus thrombosis seen on CT. This was later read as negative for thrombosis by a senior radiology attending. He underwent a right myringotomy by ENT during his hospital stay and wound cultures grew MSSA. He was treated with antibiotics for 7 days, and then was discharged with a PICC line to have 2 additional weeks of antibiotic therapy at home.
1) What is the most common intracranial complication arising from middle ear infections?
a. Epidural abscess
b. Subdural empyema
d. External carotid artery thrombosis
e. Petrous apicitis
2) Which of the following is correct regarding the treatment of acute mastoiditis?
a. Patients should be made NPO and preoperative laboratory studies should be obtained immediately since the majority of cases require surgical intervention
b. Antibiotic therapy should always include coverage for anaerobes
c. In an afebrile patient with stable vital signs and no intracranial complications seen on imaging radiographs, ED discharge with PO antibiotics and close ENT follow-up is appropriate
d. Initial therapy should include a third-generation cephalosporin or chloramphenicol with a semisynthetic penicillin, with clindamycin as an option for penicillin allergic patients
e. Administer topical antibiotics, PO challenge and follow-up with ENT
3) Other than clinical examination, what is the next most useful diagnostic modality used to diagnose this condition?
b. Schuller view radiographs
c. Myringotomy with tympanocentesis
d. CT scan
e. Blood cultures
1) A. Epidural abscesses are the most common intracranial complication arising from middle ear infections. They usually result from contiguous spread after bony destruction that can occur secondary to mastoiditis. Subdural empyemas and meningitis, in contrast, typically result from hematogenous spread. Subdural empyemas are more commonly associated with sinusitis rather than otitis or mastoiditis. Carotid artery involvement is a rare complication of infectious processes such as mastoiditis. It may manifest as thromboses of the sigmoid sinuses, or complete carotid occlusion or rupture. The internal carotid artery is typically involved. Petrous apicitis, or petrousitis, is a rare complication of mastoiditis that involves the temporal bone, not intracranial structures.
2) D. ENT should be consulted early in the event that surgical intervention is required. Indications for surgery include failure of medical therapy or the presence of complications such as temporal bone involvement or intracranial complications (see discussion). Otherwise, initial therapy involves hospital admission and parenteral antibiotics. Antibiotic selection should include coverage for the most common causative bacterial organisms. Overall, S. pneumoniae is the most common pathogen. S. aureus, S.epidermidis, group A streptococci are also common. P. aeruginosa is predominantly found in cases of chronic mastoiditis.
3) D. Although the diagnosis of mastoiditis can be made clinically, the most important diagnostic imaging test is a CT scan of the temporal bones with contrast. CT scan performed early can detect intracranial complications as well as the degree of temporal bone involvement. This is important in terms of whether the patient requires surgical intervention vs. conservative therapy with parenteral antibiotics. CT also has the advantage of being readily available at most places. In cases of intracranial complications, an MRI should subsequently be performed. MRI has a higher sensitivity than CT for detection of extra-axial fluid collections as well as vascular problems. Schullar-view radiographs refers to plain film radiographs of the temporal bone. This has been replaced by high resolution CT scanning. Myringotomy is a surgical procedure that involves an incision of the eardrum in order to drain fluid or pus. Wound cultures can be performed at the time of myringotomy, but myringotomy is a treatment for mastoiditis, not a diagnostic test for it. Blood cultures are not used to diagnose mastoiditis.
Mastoiditis is an infectious and inflammatory process of the cells and bony walls of the mastoids. The incidence of mastoiditis has lessened significantly with the introduction of antimicrobial therapy. It is primarily associated with otitis media, occurring as a complication of untreated or inadequately treated acute otitis media.
During a normal episode of acute otitis media, the mastoid mucosa can be affected in varying degrees. This is due to the anatomosic continuity between the eardrum and the mastoid cells via the aditus and antrum. The closed space that forms when this passage is blocked carries with it a potential for the development of abscesses as well as bony destruction. The infectious process may spread through the aditus ad antrum and spontaneously resolve.
It can also spread anteriorly and form a Bezold abscess, or an abscess below the pinna or behind the sternocleidomastoid muscle. This occurs when osteolysis occurs at the tip of the mastoid, and the infection spreads to the soft tissues of the neck. Incomplete pneumatization of the mastoids during early childhood is thought to be a predisposing factor.
Spreading posteriorly, pus can track behind the occipital bone and cause a Citelli abscess, or osteomyelitis of the calvaria.
In addition, spread of the infection medial to the petrous air cells of the temporal bone can cause petrositis. This may present as sixth nerve palsy, facial pain, and ipsilateral otorrhea (Gradenigo syndrome). Imaging studies usually show erosion of the petrous apex and enhancement of the adjacent meninges.
A subperiosteal abscess forms with lateral spread to the surface of the mastoid process.
Intracranial complications are rare since the introduction of antibiotic therapy. The most common intracranial complication from middle ear infections are epidural abscesses. They usually result from contiguous spread following bony destruction that can occur in mastoididits. An epidural abscess can lead to dural venous thrombosis. The resultant impairement of venous drainage can also lead to hydrocephalus in extreme cases.
Other complications of untreated mastoiditis include osteitis, labyrinthitis, meningitis, encephalitis, brain abscess, carotid artery involvement, and damage to cranial nerve VII. Newborns and immunosupressed patients are at increased risk of latent mastoiditis, which is more indolent in nature than acute mastoiditis and may present as an intracranial complication without an obvious source.
Signs and symptoms of acute mastoiditis include otalgia, otorrhea, fever, headaches, hearing loss, outward and downward displacement of the pinna, posterior auricular tenderness, edema, and abnormal tympanic membrane (e.g. erythema, perforation, bulging, scarring). However in up to 10% of cases the TM appears normal. Common symptoms of intracranial involvement include worsening otorrhea, fevers, or headaches with later development of altered mental status, cranial nerve palsies, focal neurological findings, and meningismus.
The most frequent causative organism of acute mastoiditis is S. pneumoniae. S. aureus, S.epidermidis, group A streptococci are also common. P. aeruginosa is predominantly found in cases of chronic mastoiditis.
With regard to imaging diagnosis, radiographs of the mastoid area may appear normal, but can also show opaqueness or loss of pneumotization. A CT scan of the temporal bone confirms the diagnosis and identifies the presence of complications such as the degree of temporal bone involvement and the presence of intracranial complications. CT scans also have the advantage of being more readily available than MRIs and usually do not require sedation. MRI is performed is an intracranial complication is suspected or seen on CT. MRI is more sensitive for the detection of extraaxial fluid and an MRA can be performed if vascular involvement is suspected.
Once a patient is diagnosed with mastoiditis, they require hospital admission and parenteral antibiotic therapy. Commonly used antibiotics include third generation cephalosporins, or chloranphenicol with a semisynthetic penicillin. Patients with chronic mastoiditis should also receive Pseudomonal coverage with ticarcillin or ticarcillin/clavulanate. In addition to antibiotics and hospital admission, immediate ENT consultation should be done for possible surgical intervention. Operative procedures include myringotomy, myringotomy with tympanostomy tube placement, or mastoidectomy in cases of severe disease progression.
This case discussion presented by Maria Pak, MD