Perioperative antibiotics in chronic suppurative otitis media.

Chronic suppurative otitis media (CSOM) is one of the most common chronic diseases of childhood, especially in underdeveloped countries. Placement of pressure-equalizing tubes has become a standard for treating medically refractory or recurrent acute otitis media and chronic otitis media with effusion, and CSOM can develop in any child who has had a tube placed.

CSOM has received considerable attention, not only because of its high incidence and chronicity, but also because of issues such as bacterial resistance and ototoxicity with both topical and systemic antibiotics. CSOM has a profound impact on society in terms of resources utilized in treatment (i.e., topical, oral, and intravenous antibiotics, multiple office visits, and surgery) as well as the direct impact that chronic infection has on hearing. In both children and adults, infections resulting from CSOM can cause chronic hearing loss, which has a negative impact on the development of speech, language, and social interaction, as well as school and workplace performance.

Treatment of CSOM varies considerably among pediatricians, primary care physicians, and otolaryngologists. These differences exist in all aspects of CSOM, including prevention (i.e., treatment of acute otitis media), topical therapy and other drug regimens, and pre-, intra-, and postoperative antibiotic regimens. This article addresses these differences and provides a brief overview of the protocols utilized at my institution, Vanderbilt University in Nashville.

Definition

There is considerable debate in the literature regarding a precise and consistent definition of CSOM, particularly with respect to the chronicity of infection. Other inconsistencies in defining CSOM pertain to the chronicity of the perforation, the presence of otorrhea, the presence of cholesteatoma, and the presence of chronic infection in the mastoid air cell tract. In general, CSOM is defined as a chronic infection of the middle ear, eustachian tube, and mastoid in which a perforation of the tympanic membrane is present and chronic otorrhea exists.

Disagreement also exists regarding the clinical manifestation of CSOM. For example, acute otitis media with a ruptured tympanic membrane and otorrhea meets the definition expressed above in all aspects except for the chronicity of the drainage. Chronic mastoiditis is frequently associated with CSOM, and the two terms are often used interchangeably. Chronic otitis media is another frequently used term to describe CSOM, but it is often confused with chronic otitis media with effusion, which by definition involves no perforation of the tympanic membrane. A patient with a chronic perforation does not meet the criteria for CSOM if no infection or otorrhea is present. A chronic perforation can exist in a case of acute otorrhea (i.e., from acute otitis media or from acute contamination) and not be consistent with CSOM unless the chronicity of the infection has been established. (1,2)

In 2000, a consensus panel of the American Academy of Otolaryngology--Head and Neck Surgery (AAO-HNS) met to clearly define CSOM and make treatment recommendations. The panel defined CSOM as "any persistent or recurrent tympanic membrane perforation with inflammation or history of recurrent and/or persistent drainage unrelated to cholesteatoma." (3)

Bacteriology 

At Vanderbilt University, we are conducting a study of the bacteriology of CSOM with and without cholesteatoma. Our purpose is to investigate the changes in bacteriology that have occurred during the postfluoroquinolone era with respect to both topical and systemic agents. Patients with and without cholesteatoma are being studied to ascertain if the presence or absence of keratin debris results in any statistically significant difference in bacteriology. We are also studying resistance patterns in the postquinolone era. Patients who had undergone previous systemic or topical therapy were not excluded from this study. Our results will be presented at the AAO-HNS annual meeting in September 2002. (4)

Previous studies on the microbiology of CSOM have revealed that the most frequently isolated bacteria were Pseudomonas aeruginosa, Staphylococcus aureus, Proteus spp., and Klebsiella spp. (5-10) Pseudomonas spp. were by far the most common, although some studies have shown that S aureus was more common, especially when cholesteatoma was present. (11,12) Vartiainen and Vartiainen reported that there were no significant differences in bacteriology between children and adults with CSOM. (12) They also reported that bacteriologic findings had no significant effect on the incidence of complications or on postoperative hearing results.

Management

In general, both medical and surgical therapies for CSOM are directed to reach the same general goals:

* achieve a safe ear

* eradicate disease

* achieve a dry ear free of otorrhea

* preclude the need for further surgery

* stabilize or improve hearing

* prevent the future development of disease

The first-line treatment for CSOM is topical therapy. A topical antibiotic is initiated empirically on the basis of known bacteriology identified in previous studies; initial treatment is generally not culture-directed. Cultures are rarely obtained unless there is a failure to respond to topical therapy. Neomycin/polymyxin B/hydrocortisone otic suspension is one of the more widely prescribed eardrops in the United States. Its antipseudomonal activity is found in the neomycin and polymyxin B components. However, resistance to neomycin has been seen in Pseudomonas infections. (13)

Concerns about ototoxicity led to a decline in the use of aminoglycoside-containing eardrops (i.e., neomycin, gentamicin, and tobramycin). Quinolone-containing drops (i.e., ciprofloxacin/hydrocortisone and ofloxacin) exhibit excellent antipseudomonal activity, broad antimicrobial activity, and no ototoxicity. (6,10,14)

The importance of a thorough examination of the chronically draining ear cannot be overemphasized. The size, location, and number of perforations should be documented, and the nature of the otorrhea should be noted. Documenting the presence of cholesteatoma is imperative, although this might not always be a simple task in a severely inflamed ear. The ear canal should be inspected for edema, dermatitis, infection, exposed bone, cholesteatoma, and erosion. When a standard office examination is not possible in a young child with a severely inflamed ear, examination under anesthesia is recommended.

Daily cleaning under the operative microscope to remove debris and otorrhea and to facilitate the administration of topical antibiotic drops is preferred but impractical in most practices. Swabbing the debris and otorrhea from the external canal helps facilitate drug delivery. Acetic acid irrigation is a useful adjunct to antibiotic drops in the chronically draining ear. At Vanderbilt, we instruct patients/caregivers to irrigate the ear with acetic acid solution between office visits in order to remove debris and facilitate delivery of the antibiotic drops. The antibiotic is then instilled immediately after irrigation has been completed. This technique has not only a mechanical benefit, but an antibacterial effect, because acetic acid is effective in inhibiting the growth of P aeruginosa. Using a combination of acetic acid and aluminum (Burow's solution) results in an even a greater inhibition of P aeruginosa. (15)

Systemic antibiotics are used in the event that topical antibiotic therapy fails. Systemic oral antibiotics (e.g., quinolones) have been used with success in adults with CSOM (they are not indicated for use in children). Likewise, systemic IV antibiotics have been used successfully in treatment failures in both adults and children. (9,16,17) Although we do not usually use IV antibiotics at our institution, we do consider them for patients with bilateral CSOM, especially children.

Perioperative prophylactic antibiotics

In a controlled study, Jackson found that the administration of prophylactic antibiotics in ear surgery did not significantly improve grafting success rates or postoperative infection rates. (18) Despite the compelling evidence reported in this large study, we continue to use prophylactic antibiotics in surgery for CSOM--generally a single dose of IV cefazolin. In a very actively draining ear, we use an IV antipseudomonal antibiotic (e.g., ticarcillin/clavulanate, ceftazidime, or, less often, piperacillin or aztreonam). Approximately 90% of our patients who undergo surgery for CSOM are discharged home on the day of the procedure. Rarely is a patient admitted to continue IV antibiotics.

We also use antibiotics intraoperatively. A 50,000-U dose of bacitracin (one-half ampule per liter of saline) or 400 mg of ciprofloxacin is added to the sterile saline used for intermittent irrigation (not the hanging saline used for suction irrigation). The middle ear is packed with saline-soaked Gelfoam. No neomycin/polymyxin B/hydrocortisone-soaked Gelfoam is used in the middle or external ear. Antibiotic ointments that contain an aminoglycoside have been used in the past, but they are no longer used. Mupirocia ointment is used in the external canal to secure the graft and maintain the canal's patency.

We continue antibiotics for 5 to 7 days after discharge with an antistaphylococcal antibiotic (e.g., amoxicillin/clavulanate or cephalexin) or an antipseudomonal antibiotic (e.g., a quinolone) in adults. Patients are instructed to keep the ear dry and to change cotton balls as necessary. We do not use antibiotic drops during the immediate postoperative period.

Postoperative care

We perform a follow-up assessment of most patients in the clinic 2 to 3 weeks following surgery. Subsequent periodic visits are scheduled as the clinical picture dictates. For patients who have undergone a canal-wall-intact procedure, we gently remove the antibiotic ointment, dried blood, and Gelfoam from the ear, provided that an atraumatic removal is possible. These patients are followed up again at the clinic in approximately i month (sooner if the clinical picture dictates). For patients who have undergone a canal-wall-down procedure, we do not usually remove the Gelfoam and ointment, because they help prevent postoperative webbing of the mastoid cavity. These patients are followed every 1 or 2 weeks after the initial visit, usually for up to 6 or 8 weeks.

We use gentian violet liberally in all postoperative patients, particularly those who have had a canal-wall-down procedure. Applied with a cotton-tipped applicator, dropper, or a wire loop, gentian violet is an effective drying agent, and it controls granulation tissue and allows for epithelialization. We use silver nitrate sparingly because it can impair epithelialization; we reserve it for patients with abundant granulation tissue.

We generally start antibiotic drops at the first postoperative visit. Drops are effective in reducing granulation tissue, treating inflammation or infection, and minimizing adhesions and fibrosis. We usually start ciprofloxacin/hydrocortisone or ofloxacin drops in the postoperative period. When these drops are used in conjunction with gentian violet, they are usually started 5 days after the application of gentian violet to allow the gentian violet to dry and be effective. The addition of a steroid is especially effective in the postoperative period because of its anti-inflammatory properties, which might treat or prevent inflammation or granulation tissue and possibly prevent webbing, adhesions, or stenosis.

The draining mastoid cavity

The principles of CSOM treatment also apply to treating the chronically draining mastoid cavity. A thorough otomicroscopic examination for perforation, exposed middle ear mucosa, and cholesteatoma is paramount. Methods to control infection, otorrhea, and granulation tissue with gentian violet, antiseptic and antibiotic drops, and systemic antibiotics are similar to those used for treating CSOM. A careful follow-up evaluation is generally performed every 6 months.

We often use powders to treat a chronically draining mastoid cavity. They have a mechanical drying effect and they deliver antibiotics and other agents (i.e., antifungals) that might not be usually found in commercially available ototopical agents. One of the more frequently used in otolaryngologic practice is CSF powder--a mixture of chloramphenicol, sulfadiazine, and Fungizone (amphotericin B). We currently use a powder made up of amphotericin B, sulfanilamide, chloramphenicol, hydrocortisone, and corn starch. This mixture has been successful in treating refractory draining mastoid cavities and external ear infections.

In conclusion, the type of antibiotic therapy used in the pre-, intra-, and postoperative periods varies widely among physicians and will most likely continue to do so. Our treatment protocols have evolved considerably and will continue to change as new data continue to emerge regarding the bacteriology of CSOM, bacterial resistance, and ototoxicity.

References

(1.) Bluestone CD. Efficacy of ofloxacin and other ototopical preparations for chronic suppurative otitis media in children. Pediatr Infect Dis J 2001;20:111-5.

(2.) Bluestone CD. Acute and chronic mastoiditis and chronic suppurative otitis media. Seminars in Pediatric Infectious Diseases 1998;9:12-26.

(3.) Hannley MT. Denneny JC III, Holzer SS. Use of ototopical antibiotics in treating 3 common ear diseases. Otolaryngol Head Neck Surg 2000;122:934-40.

(4.) Moore BA, Haynes DS. The bacteriology of otorrhea in a tertiary care referral-based otology practice. To be presented at the annual meeting of the American Academy of Otolaryngology--Head and Neck Surgery: San Diego; September 2002.

(5.) Attallah MS. Microbiology of chronic suppurative otitis media with cholesteatoma. Saudi Med J 2000;21:924-7.

(6.) Miro N. Controlled multicenter study on chronic suppurative otitis media treated with topical applications of ciprofloxacin 0.2% solution in single-dose containers or combination of polymyxin B, neomycin, and hydrocortisone suspension. Otolaryngol Head Neck Surg 2000;123:617-23.

(7.) Altuntas A, Aslan A, Eren N, et al. Susceptibility of microorganisms isolated from chronic suppurative otitis media to ciprofloxacin. Eur Arch Otorhinolaryngol 1996;253:364-6.

(8.) Fliss DM, Dagan R, Meidan N, Leiberman A. Aerobic bacteriology of chronic suppurative otitis media without cholesteatoma in children. Ann Otol Rhinol Laryngol 1992;101:866-9.

(9.) Arguedas A, Loaiza C, Herrera JF, Mohs E. Antimicrobial therapy for children with chronic suppurative otitis media without cholesteatoma. Pediatr Infect Dis J 1994;13:878-82

(10.) Indudharan R, Haq JA, Aiyar S. Antibiotics in chronic suppurativeotitis media: A bacteriologic study. Ann Otol Rhinol Laryngol 1999;108:440-5.

(11.) Anifasi WB, Tumushime-Buturo CG. Bacteriology and drug sensitivity of chromic suppurative otitis media at a central hospital in Zimbabwe. Cent Afr J Med 1989;35:481-3.

(12.) Vartiainen E, Vartiainen J. Effect of aerobic bacteriology on the clinical presentation and treatment results of chronic suppurative otitis media. J Laryngol Otol 1996;110:315-8.

(13.) Dohar JE, Kenna MA, Wadowsky RM. In vitro susceptibility of aural isolates of Pseudomonas acruginosa to commonly used ototopical antibiotics. Am J Otol 1996;17:207-9.

(14.) Dohar JE, Garner ET, Nielsen RW, et al. Topical ofloxacin treatment of otorrhea in children with tympanostomy tubes. Arch Otolaryngol Head Neck Surg 1999;125:537-45.

(15.) Thorp MA, Kruger J, Oliver S, et al. The antibacterial activity of acetic acid and Burow's solution as topical otological preparations. J Laryngol Otol 1998;112:925-8.

(16.) Kenna MA, Bluestone CD, Reilly JS, Lusk RP. Medical management of chronic suppurative otitis media without cholesteatoma in children. Laryngoscope 1986:96:146-51.

(17.) Somekh E, Cordova Z. Ceftazidime versus aztreonam in the treatment of pseudomonal chronic suppurative otitis media in children. Scand J Infect Dis 2000;32:197-9.

(18.) Jackson CG. Antimicrobial prophylaxis in ear surgery. Laryngoscope 1988;98:116-23.

David S. Haynes, MD

Dr. Haynes is director of otology and neurotology at the Vanderbilt University Medical Center and the St. Thomas Hospital Neuroscience Institute in Nashville. He is also an associate professor in the Department of Otolaryngology and the Department of Hearing and Speech Sciences.