Acute suppurative otitis media is an acute suppurative inflammation of the middle ear mucosa, mostly in children, predominantly in winter and spring, and is often secondary to upper respiratory tract infection.
Etiology
The main pathogens are pneumococcus, Haemophilus influenzae, hemolytic streptococcus, and staphylococcus. The common routes of infection are eustachian tube, external auditory canal, and hematogenous dissemination.
Bacteria invade the middle ear through the eustachian tube and cause infection.
The disease can be complicated by acute infectious diseases, such as scarlet fever, measles, and pertussis，through the eustachian tube. Acute suppurative otitis media can also be a local manifestation of these infectious diseases, and often involves bones, destroys the ossicles, and causes severe necrotic lesions.
Improper swimming or diving, improper valsalva maneuver or nasal discharge, and improper eustachian tube insufflation or nasal treatment can result in the entry of bacteria into the middle ear through the eustachian tube.
The Eustachian tube in infants and children has short lumen, wide inner diameter, and low position of the tympanic orifice. Therefore, pharyngeal bacteria or secretions can easily retrogradely invade the tympanic cavity. For example, when bottle feeding in supine position, milk and gastric contents can retrograde into the middle ear through the eustachian tube.
In case of tympanocentesis, tympanostomy, and tympanic membrane trauma, pathogens directly enter the middle ear through the external auditory canal.
Hematogenous infection is extremely rare.
Pathology
In the early stage of infection, the middle ear mucosa is congested and edematous, and the pharyngeal orifice of the eustachian tube is obstructed. The oxygen in the tympanic cavity is resorbed, resulting in negative pressure. There are exudation of plasma, fibrin, erythrocytes, and polymorphonuclear leukocytes; thickened mucosa; ciliary shedding; and increased goblet cells. Inflammatory exudate accumulates in the tympanic cavity and gradually turns to purulent. The pressure in the tympanic cavity increases with the accumulation of pus. The tympanic membrane is compressed, resulting in blood supply obstruction. The tympanic membrane bulges locally and is involved by inflammation, resulting in thrombophlebitis, eventually leading to local necrosis, rupture, tympanic membrane perforation, and purulent discharge. With proper treatment and adequate drainage, the inflammation can gradually subside, the mucosa returns to normal, and small tympanic membrane perforation can heal spontaneously.
Clinical manifestations
Most patients have severe pain prior to tympanic membrane perforation, and throbbing pain or stabbing pain can radiate to the ipsilateral head or teeth. Relieved otalgia is preceded by tympanic membrane perforation and purulent discharge.
In the early stage of the disease, there are often significant aural fullness, low pitched tinnitus, and hearing deterioration. After tympanic membrane perforation and purulent discharge, hearing deterioration is relieved because the pus that affects the mobility of the tympanic membrane and the ossicular chain has been discharged. In patients with severe otalgia, hearing impairment is often ignored. Some patients may also have vertigo.
After the tympanic membrane is perforated, fluid may flow out of the ear, initially bloody and purulent, subsequently mucopurulent.
Figure 1 Acute suppurative otitis media
Systemic symptoms include chills, fever, fatigue, and anorexia. Children have more severe systemic symptoms, often accompanied by emesis and diarrhea. Once the tympanic membrane is perforated, the body temperature quickly returns to normal and the systemic symptoms are significantly alleviated.
In the early stage of the disease, the flaccid part of the tympanic membrane is congested, and radially dilated blood vessels can be seen around the handle of the malleus and the tense part. Subsequently, the tympanic membrane is diffusely congested, swollen, and bulged outward. Normal signs vanish, and small yellow spots can be seen locally. If the inflammation cannot be controlled promptly, tympanic membrane perforation may occur. Generally, the perforation is small and difficult to see in the early stage. There is a pulsating bright spot at the perforation, which is termed lighthouse sign. In fact, pus is gushing out from this place. Necrotizing tympanic membrane quickly collapses, forming a large perforation.
There may be mild tenderness in the mastoid, apparently in the tympanic sinus.
Hearing test shows mostly conductive hearing loss, and few patients may have mixed hearing loss or sensorineural hearing loss due to cochlear involvement.
The total count of white blood cells is increased, the count of neutrophils is increased, and the blood count gradually returns to normal after the tympanic membrane is perforated.
Diagnosis
Based on the medical history and clinical manifestations, a diagnosis can be readily established.
Differential diagnosis
Acute external otitis and external auditory canal furunculosis
The main manifestations are otalgia and apparent auricular tenderness. The external auditory canal opening and auditory canal are swollen, developing into furuncle in the late stage. The inflammation on the surface of the tympanic membrane is mild. Generally, hearing is normal.
Acute myringitis
The disease is mostly complicated by influenza and herpes zoster oticus, with severe otalgia and inapparent hearing deterioration. Examination shows congested tympanic membrane and bulla formation. Generally, there is no tympanic membrane perforation.
Treatment
Systemic treatment
Sufficient antibiotics can be used as soon as possible to control infection. Generally, penicillin and cephalosporins can be selected. In case of prompt treatment, tympanic membrane perforation can be prevented. After tympanic membrane perforation, pus is collected for bacterial culture and antibiotic sensitivity test, and sensitive antibiotics can be used according to the results. Supportive therapy such as rehydration is given to patients with severe systemic symptoms.
Local treatment
Before tympanic membrane perforation
1% phenol glycerol ear drops can be used to reduce inflammation and relieve pain, and nasal drops containing vasoconstrictors can be used in supine head hanging position to improve the patency of the eustachian tube and reduce local inflammation. In case there are severe systemic or local symptoms, the tympanic membrane is markedly bulging, and there is no significant relief after general treatment, myringotomy can be performed under sterile conditions to facilitate drainage. In patients with redness, swelling, and tenderness in the posterosuperior auricle, acute mastoiditis is suspected, and mastoid incision and drainage should be considered after confirmation through CT.
After tympanic membrane perforation
3% hydrogen peroxide solution can be used to thoroughly clean the pus in the external auditory canal, and suction devices can also be applied to remove the pus.
Antibiotic ear drops can be used. Powdered substances are prohibited to avoid agglomeration with pus, which may affect drainage.
When the pus is reduced and the inflammation gradually subsides, 3% boric acid ethanol glycerol, 3% boric acid ethanol, and 5% chloramphenicol glycerol ear drops can be used. After the infection is completely controlled and the inflammation thoroughly subsides, the tympanic membrane perforation in some patients can heal spontaneously.
Chronic diseases of the nasal cavity, sinuses, pharynx, and nasopharynx, such as hypertrophic rhinitis, chronic sinusitis, adenoid hypertrophy, and chronic tonsillitis, should be treated properly, which helps prevent the recurrence of otitis media.
Prevention
Health knowledge about correct nasal discharge and bottle feeding can be popularized. Upper respiratory tract infection and respiratory infectious diseases should be promptly treated. Patients with tympanic membrane perforation or tympanostomy should avoid swimming and other activities that may cause water to enter the ear.