What is new in otitis media?

Abstract

The "wait and see" approach in acute otitis media (AOM), consisting of postponing the antibiotic administration for a few days, has been advocated mainly to counteract the increased bacterial resistance in respiratory infections. This approach is not justified in children less than 2 years of age and this for several reasons. First, AOM is an acute inflammation of the middle ear caused in about 70% of cases by bacteria. Redness and bulging of the tympanic membrane are characteristic findings in bacterial AOM. Second, AOM is associated with long-term dysfunction of the inflamed eustachian tube (ET), particularly in children less than 2 years of age. In this age group, the small calibre of the ET together with its horizontal direction result in impaired clearance, ventilation and protection of the middle ear. Third, recent prospective studies have shown poor long-term prognosis of AOM in children below 2 years with at least 50% of recurrences and persisting otitis media with effusion (OME) in about 35% 6 months after AOM. Viruses elicit AOM in about 30% of children. A prolonged course of AOM has been observed when bacterial and viral infections are combined because viral infection is also associated with ET dysfunction in young children. Bacterial and viral testing of the nasopharyngeal aspirate is an excellent tool both for initial treatment and recurrence of AOM. Antibiotic treatment of AOM is mandatory in children less than 2 years of age to decrease inflammation in the middle ear but also of the ET particularly during the first episode. The best choice is amoxicillin because of its superior penetration in the middle ear. Streptococci pneumoniae with intermediary bacterial resistance to penicillin are particularly associated with recurrent AOM. Therefore the dosage of amoxicillin should be 90 mg/kg per day in three doses. In recurrent AOM with beta-lactamase-producing bacilli, amoxicillin should be associated with clavulanic acid at a dose of 6.4 mg/kg per day. The duration of the treatment is not established yet but 10 days is reasonable for a first episode of AOM. OME may be a precursor initiating AOM but also a complication thereof. OME needs a watchful waiting approach. When associated with deafness for 2-3 months in children over 2 years of age, an antibiotic should be given according to the results of the bacterial resistance in the nasopharyngeal aspirate. The high rate of complications of tympanostomy tube insertion outweighs the beneficial effect on hearing loss. The poor results of this procedure are due to the absence of effects on ET dysfunction. Pneumococcal vaccination has little beneficial effects on recurrent AOM and its use in infants needs further studies. Treatment with amoxicillin is indicated in all children younger than 2 years with a first episode of AOM presenting with redness and bulging of the tympanic membrane. Combined amoxicillin and clavulanic acid should be given in patients with beta-lactamase-producing bacteria. The duration of treatment is estimated to be at least 10 days depending on the findings by pneumo-otoscopy and tympanometry. Bacterial and viral testing of the nasopharyngeal aspirate is highly recommended particularly in children in day care centres as well as for regular follow-up. The high recurrence rate is due to the long-lasting dysfunction of the eustachian tube and the immune immaturity of children less than 2 years of age.

Fig. 1

The three main types of tympanograms showing: a a peak near atmospheric pressure expressed in daPa with stapedius reflex for different Hz frequencies, b a flat curve without stapedius reflex for 500, 2000, 4000 Hz pointing to presence of middle ear exudate: AOM or OME, c a lower peak in the negative pressure zone (−235 daPa) with an enlarged width pointing to OME with partial permeability of ET to air entrance and still a stapedius reflex

Fig. 2

Three physiologic functions of the eustachian tube in relation to the middle ear. NP nasopharynx, ET eustachian tube, TVP tensor velum palatinum muscle, ME middle ear, MAST mastoid, TM tympanic membrane, EC external canal

Fig. 3

The difference in the angle of the eustachian tube between infants and adults [5]

Fig. 4

The tympanic membrane forms the lateral wall of the box-shaped middle ear. The function of the eustachian tube is to equilibrate middle ear pressure with that in the nasopharynx. Bacteria and viruses resident in the nasopharynx may reach the middle ear during pressure equilibration. One-third of the middle ear mucosa and the entire eustachian tube are lined with mucociliary epithelium to transport bacteria from the middle ear back to the nasopharynx. Air from the middle ear enters the mastoid air cells by way of the aditus