Therapy depends on the bacterial cause of the disease and on the results of antibacterial susceptibility testing. Additional considerations in selecting an antimicrobial drug include the patient’s age associated illness, otitis media history, antimicrobial drug treatment history, and community bacterial susceptibility patterns.
Infants younger than 4 weeks of age have a higher incidence of AOM caused by Staphylococcus aureus and gram-negative enteric bacilli; this is especially true for infants in neonatal intensive care units who have undergone prolonged nasotracheal intubation. Infants without these risk factors tend to have AOM caused by the same bacteria that cause it in older children. Because diagnosing systemic infection can be difficult in neonates, infants less than 4 weeks of age who have AOM with fever or irritability are often hospitalized for a sepsis evaluation (blood culture, lumbar puncture, urine and cerebrospinal fluid antigen) and parenteral treatment with antibiotics pending culture results. Ampicillin and gentamicin are generally selected for neonates with intensive care exposure, and ampicillin and cefotaxime for those without. Whenever possible,, middle ear effusion aspiration (tympanocentesis) for culture is performed before initiating treatment. Nafcillin is added if the effusion Gram stain or clinical situation suggests infection with S.Aureus.
Infants and children older than 4 weeks of age can usually be treated as outpatients if no clinical signs or symptoms suggest systemic infection. Antimicrobial drugs used to treat AOM should be active against the common middle ear bacterial pathogens: Streptococcus pneumoniae, Hemophylus influenzae, Moraxella catarrhalis and Streptococcus pyogenes.
Amoxicillin and TMP-SMZ an increasing proportion of b-lactamase-producing H.influenzae and M.catarrhalis has suggested that amoxicillin may no longer be effective first-line therapy. There is, however, marked regional variation in the proportion of b-lactamase-producing organisms (10% to 30%), and several studies show paradoxically good clinical responses to amoxicillin despite the presence of middle ear pathogens producing b-lactamase.
Drugs that evade the action of b-lactamase include amoxicillin-clavulanate, TMP-SMZ, cefuroxime axetil, cefaclor, and erythromycin-sulfisoxazole. In communities with a high proportion of b-lactamase-producing organisms, TMP-SMZ is often the first-line drug. Like amoxicillin, it is less expensive than the other drugs and its twice-daily dosage is easier for parents. However, wide-spread use of TMP-SMZ may increase bacterial resistance.
Other antimicrobial drugs are considered second line. Their use is typically limited to children with persistent or recurrent AOM. Tympanocentesis to obtain middle ear effusion for culture is the only method to identify the causative pathogen in these cases. Recent data indicate that viral infection may be a significant factor in treatment failure and underscore the value of tympanocentesis, yet it is not commonly performed even in refractory cases of otitis media. Typically, a sequence of different antibiotics is described in the hope that one will eventually clear the middle ear inflammation. Cefalor is less stable to the hydrolytic action of b-lactamase than either cefixime or cefuroxime axetil; cefalor also has less bacteriologic effectiveness against H.influenzae than either TMP-SMZ or amoxicillin-clavulanate. Cefixime appears to have reduced bacteriologic efficacy against Pneumococcus, but it may be more active than amoxicillin against H.influenzae.
Several antibiotics are not sufficiently broad spectrum to be useful in treating AOM. These include three drugs with inadequate coverage of H.influenzae (erythromycin, penicillin, and first-generation cephalosporins such as cephalexin and cephradine) and the sulfonamides alone, which inadequately cover Pneumococcus and group A Streptococcus.
Sulfonamide-containing drugs are contraindicated in children younger than 8 weeks of age;sulfonamides may displace bilirubin from its binding sites on albumin and have the potential of exacerbating jaundice and theoretically increasing the risk of kernicterus. Cefixime is not approved for use in infants younger than 6 months of age. The absence of a liquid form of cefuroxime axetil limits its use.
Antimicrobial drug selection is also influenced by the presence of diarrhea, conjunctivitis, and pharyngitis. Many practitioners avoid using amoxicillin-clavulanate, EES-SSZ, cefuroxime axetil, and cefixime in the presence of abdominal discomfort or diarrhea, because they believe that the drugs aggravate gastrointestinal symptoms. However, the reported incidence of vomiting and diarrhea is similar with the use of any of these drugs.
Patients with purulent conjunctivitis and AOM have an increased risk of infection with H.influenzae organisms, 30% of which are resistant to amoxicillin in many communities; thus a b-lactamase resistant antibiotic is often selected. Patients with exudative pharyngitis, cervical adenitis, and AOM should usually have a throat culture for group A b-hemolytic streptococci. Because TMP-SMZ may have reduced efficacy against this organism, an alternate antibiotic is usually selected in such cases.
Patients with sinusitis or pneumonia in addition to AOM usually can be treated with the same antibiotic, because a similar spectrum of pathogens cause these illnesses. Severe sinusitis or pneumonia usually requires coverage for S.aureus and b-lactamase-producing H.influenzae and M.catarrhalis; amoxicillin-clavulanate or cefuroxime axetil would be a reasonable choice. A school-aged child with AOM and pneumonia may have Mycoplasma pneumoniae infection, and EES-SSZ is an appropriate choice. Likewise, in an infant younger than 6 months of age with AOM and a febrile pneumonia, EES-SSZ is appropriate because Chlamydia trachomatis may be the cause of both middle ear and lung disease.
Patients with suspected intratemporal or intracranial complications (e.g., mastoiditis, epidural abscess) need immediate expert evaluation, parenteral antibiotic treatment, and, usually surgical exploration or drainage.
Additional supportive therapy, including analgesics, antipyretics, and local heat, is usually helpful. Meperidine hydrochloride may also be required for sedation. An oral descongestionant (e.g., pseudoephedrine hydrochloride) may relieve some nasal congestion and antihistamines may help patients with known or suspected nasal allergy. The efficacy of antihistamines and decongestants in the treatment of AOM, however, is not established.
In patients with unusually severe earache, myringotomy may be performed initially to provide immediate relief.
If the patients clinical manifestations of acute infection increase during the 1st 24 hr despite antimicrobial therapy a concurrent infection such as meningitis or a suppurative complication of otitis media should be suspected. The child should be re-examined and tympanocentesis and myringotomy performed. Similarly, if the patient continues to have appreciable pain, fever, or both after 24-48 hr, tympanocentesis and myringotomy should be performed as diagnostic and therapeutic procedures, identification of the organism(s) is recommended at this stage bit, when a diagnostic aspiration is not performed, antimicrobials affective against resistant organisms prevalent in the community should be administered.
For several decades american practitioners have customarily treated AOM with an antibiotic drug(s) for 10 to 14 days. Recently, favorable results with shorter duration of treatment have been reported by swedish, british and american investigators.
Longer treatment might be appropriate to eradicate slowly replicating bacteria, a situation that may exist in chronic OME. Antibiotic tolerance may be significant when bacteria are in a stationary growth phase. On the other hand, shorter treatment might be indicated for less severe disease, so as not to interfere with the development of type-specific antibodies and, hypothetically, not to increase susceptibility to recurrent disease.
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