1.  Otitis externa is often caused by Pseudomonas and should be treated by cleansing the ear canal, and administration of eardrops.  Placement of an ear canal wick may also be necessary.

2.  Indications for myringotomy tubes are: persistent hearing loss from chronic serous otitis media, ear drum retraction pocket formation associated with eustachian tube dysfunction, and recurrent otitis media unresponsive to prophylactic antibiotics.

3.  A cholesteatoma is an epidermoid cyst in the middle ear and mastoid, which usually occurs from a preexisting retraction pocket.  Its removal requires major surgery and if left unattended severe complications can occur.  

4.  Intravenous antibiotics and a myringotomy can often manage uncomplicated acute coalescent mastoiditis.

5.  Ear drops and oral antibiotics should be prescribed for children with a draining otitis media.

PHYSICAL EXAMINATION OF THE EAR:
            A physician should be familiar with the normal landmarks of the ear canal and eardrum.  The following structures should be evaluated: cartilagenous ear canal, bony ear canal, malleus (manubrium, umbo, lateral process), eardrum (pars flaccida, pars tensa).  One commonly identifies the following ear drum and canal changes.  They usually are self-limiting and if not extensive, require monitoring only.

Tympanosclerosis:  White calcific plaques located in the fibrous layer of the drum.  They usually signify previous ear infections.  They are not of clinical significance unless they fix the drum by extending to the bony canal.

Osteoma:  Solitary, pedunculated, benign bone growth seen in the ear canal.  They need no treatment if small and asymptomatic.

Exostoses:  Multiple, sessile, benign bone growth, usually from chronic cold stimulation (swimming in cold water).  No treatment is necessary if small and asymptomatic.

EAR INFECTIONS AND EUSTACHIAN TUBE DYSFUNCTION:

Acute External Otitis ("Swimmer's ear"):
A painful, swollen ear canal with inflammation and infected debris.  There may be minimal pus.  The common pathophysiology of otitis externa is chronic moisture trapping, elevated pH, and bacterial overgrowth with edema and infected debris.

Treatment:
The cornerstone of treatment is topical medicinal drops to open the ear canal for drainage.  If the canal is swollen closed an otic wick should be used to allow eardrops to penetrate the full length of the ear canal.  The most common organisms are pseudomonas and proteus.  Staphylococcal and streptococcal species along with candida can also be found.  Oral antibiotics are often effective.  If the patient is a compromised host or is having systemic symptoms, hospitalization and administration of intravenous antibiotics may be necessary.  Third generation cephalosporins such as ceftazidime have replace aminoglycoside therapy.  

Eardrops are always used and are well tolerated if the eardrum is intact.  Basically there are two types of drops, those with active ingredient of an antibiotic and those whose action is dependent upon chemical sterilization of the ear canal (alcohol, boric acid and acetic acid drops).  The latter drops usually cause pain in the middle ear and are usually not used in the presence of a tympanic membrane perforation.  The antibiotic drops often contain Neomycin, which is the second most inferior along the conchal and lobule of the ear.1  Although no known cases of ototoxicity have been reported from topical use in the external or middle ear of man, its use should be stopped soon after resolution of the infection.  Cortisporin Otic Suspension and Solution are drops that contain Neomycin.  The solution will cause pain if it enters the middle ear through an ear drum perforation.  Most eye drops can be used in the ear but the opposite is not true.  Eye drops are non-irritation and can usually be used in a patient with a perforated eardrum without causing pain.

Specific types of drops are as follows:
1.  VoSol HC: Acetic acid; hydrocortisone reduces edema.
2.  Cortisporin otic (Polymyxin B, Neomycin, Hydrocortisone)  Neomycin: #1 topical sensitizer: water base which may increase edema.
                        -- Suspension: cloudy, well tolerated in the middle ear.
                        -- Solution:  clear, causes pain if reaches middle ear.
3.  Burrows solution: 1/50 or 1/40 dilution tolerated in middle ear.
4.  Boric acid/Acid ETOH drops: Hurts if perforation is present.  1 part      saturated solution of boric acid, 2 parts of 95% ETOH.
5.  ETOH/Acetic Acid drops (1 part of 95% acid ETOH and 1 part of 25% acetic acid).  Hurts if perforation is present.
6.  Garamycin (gentamicin) Drops: Eye drop.  Used for refractory pseudomonas infections.
7.  Colymycon-Otic/with Neomycin (Neomycin, Colistin, Thanzonium Bromide (promotes drop penetration and hydrocortisone.)
8.  Pediatric (Polymycin  Bacitracin, Hydrocortisone pH balanced with alcohol)

 
Chronic otitis externa:
Characterized by puritis and drying of the ear canal.  In humid climate a fungus often causes it.  Lotrimin ear drops, tinactin solution, and Mycolog cream can be used for treatment.  In severe non-responsive cases associated with pain and gross hyphae, oral Ketoconazole may be effective.  In this situation, repeated cleansing of debris is as important as chemotherapy, Persistent suppurative external otitis should arouse suspicion of a foreign body in the external ear canal.
 

Malignant Otitis Externa:
This is a fulminated pseudomonas infection of the soft tissues along the base of the skull that originates from an otitis externa.  It usual occurs in diabetics and other compromised hosts.  The pseudomonas infection causes a vasculitis that crates a zone of necrotic and avascular tissue.  Treatment is long term (months) I.V. antibiotics with the role of surgery reserved for severe cases.  As the name implies, this disease can be fatal and is best prevented.  Thus, otitis externa should not be taken lightly in the compromised host and close follow up with hospitalization of severe, non-responding cases is necessary.  It is most common in elderly, poorly controlled diabetics.

 
Acute Otitis Media:
Acute Otitis Media is one of the most common causes of childhood fever.  In general, 1/3 of the children will have many episodes (6 or more), 1/3 several, and 1.3 none or one episode.  The most common etiologic organisms are Hemophilus influenza, Streptococcus pneumonia and streptococcal pyrogenes.  The first two organism account for 64 to 70% of infections.2,3 Therapy consists of oral antibiotics.  Ampicillin, Amoxicillin, sulfa/Erythromycin, Ceclor and Augmentin are commonly used.  The former antibiotics are much less expensive but have an increasing number of treatment failures than the latter.  For this reason many physicians use Ampicillin and Amoxicillin as their first line of therapy and the latter for treatment failures.  Sulfa should not be given to children less than 3 months of age (12 months conceptional age).  The exact choice has to take into consideration the wishes and social economic situation of the patient.  Effusions found in 30% of neonates.4  Eighty-two percent of these effusions are culture positive (Staphylococcus in 35% and Enteric (gram negative) organism in 40%.  Tympanocentesis and culture should be considered in these cases.  If a child less than two months of age is febrile, hospitalization and a complete evaluation is indicated.  If the ear is draining pus, the possibility exists that contamination of the middle ear by external ear organisms (pseudomonas) will take place or that these organisms caused the otitis media through a preexisting perforation.  In this setting, eardrops should be used.

Incision and drainage of an eardrum in acute otitis media should be done for the following indications:  
1.  Pain relief in older child or adult is rarely done
2.  Culture in the neonate (less than one month)--often enteric organisms
3.  Facial Paralysis or other complication--needs a wide-field myringotomy.  Simple aspiration of drum does not affect the occurrence of CSOM after the acute infection.5

 
Complications of acute otitis media including, meningitis, labyrinthitis and facial paralysis still occasionally develop despite modern antibiotics.  When these occur, vigorous intravenous antibiotic therapy along with topical therapy though a wide myringotomy is indicated and mastoid surgery may be necessary.
 

Recurrent Acute Otitis Media:
Although eustachian tube dysfunction is felt to be a major cause of recurrent otitis media, bottle feeding infants in a supine position has been reported to cause this disorder by allowing milk and food products to enter the middle ear.6  Both the treatment and definition of recurrent acute otitis media is debated.  Children with six to twelve episodes per year certainly can be considered otitis prone and prophylactic treatment is indicated.  If the effusion totally clears between infections, prophylactic antibiotics should be tried.  Ampicillin,7 Erythromycin8 and Sulfa9, 10 have been used for this purpose.  The dosage is 1/2 to 1/3 the total daily dose and prescribed for a period of several months.  Allergic reactions and intolerance can occur.  The PDR Carries the Following warning "Bactrum (Septra) is not indicated for prophylactic or prolonged administration in otitis media at any age."  In children who do not tolerate prophylactic antibiotics, myringotomy tube insertion has been shown to prevent recurrent otitis media.11,12  Tube insertion as a method of prophylaxis has a greater role in children with a persistent effusion between the episodes of acute otitis media.

Gebhart (1981) treated 108 children with 3 or more infections during a 6-month period before therapy.  Fifty-eight children had tubes inserted.  54% of these patients had ear infections (9% had 2 or more infections) (56% of ears had fluid when tubes were inserted and 57% were culture positive).  Fifty children were controls.  (92% of controls had ear infections, 56% had 2 or more infections).  The reinsertion rate for the myringotomy tubes was 31%.

Gonzalez (1986) did a prospective randomized (Blind) study.  Compared Placebo vs. sulfonamides. Tympanostomy tube prophylaxis.  Treatment failure was 2 or more episodes of AOM in 3 months.  In the placebo group, 12 of 20 children developed an ear infection.  In the tympanostomy group, 5 of 22 children failed sig. from placebo at p<0.02.  In the sulfisoxazole group, 8 of 21 children developed an ear infection.
 

Chronic Otitis Media:
This condition is characterized by chronic purulent drainage through a tympanic membrane perforation.  The infection is usually caused by multiple organisms.  Treatment consists of eardrops, irrigations (1/4% acetic acid) and oral antibiotics.  Cleansing the middle ear with a suction catheter is done one to two times a day.  If the drainage continues, hospitalization and administration of a third generation cephalosporin is indicated.  Surgical therapy is considered is medical therapy does not clear the drainage.  Repair of the perforation along with a mastoidectomy is usually curative.  In cases of persistent ear infection, unresponsive to medical therapy, a foreign body, cholesteatoma, neoplasm, histiocytosis X and malignant otitis externa should be considered.

Otitis media with effusion (serous otitis media):
The chances of otitis media with effusion (serous otitis media) occurring at some point in the child's life is between 18% 13 to 52%.14  It occurs more frequently in the children of parents who smoke. 15,16  Transient effusions occur in almost all children and do not always require treatment.  Fifty to seventy percent of children will have an effusion 10 to 14 days after an acute otitis media and ten to fourteen percent will have one at two months.

            Duration of CSOM after an acute otitis media.17, 18

            at 10 to 14 days                                   50% to 70%

            1 month                                                22% to 20%

            2 month                                                14% to 10%

            3 month                                                6%

            Unilateral or bilateral disease made no difference.

The indications for treatment include retraction pocket formation in the tympanic membrane, recurrent otitis media, and hearing loss.  Treatment of retraction pockets can prevent the breakdown of the tympanic membrane and cholesteatoma (keratoma-skin cyst in the middle ear or mastoid) formation.  Chronic secretory otitis also affects mastoid pneumatization and its treatment will reverse the inhibitory process.19  As previously discussed, the latter indication is debated.  All children should be treated medically and observed for three or four months before myringotomy tube insertion should be considered. Factors such as language delay and anatomical reasons for the effusion (a submucous cleft of the soft palate) need to be considered in treating the patient.

The most accepted forms of medical treatment is antibiotic therapy for 4-6 month (1995), American Academy of Ped. ENT and Family Practice.  Approximately 50% of effusions have been found to be culture positive20 with the highest incidence in children under 3 years of age.  Palva21 cultured middle ear serous effusions and found Streptococcus pneumoniae in 7%, Hemophilus influenza in 9% and opportunistic bacteria in 20%.  Free capsular polysaccaride pneumococcal antigen was found in 27% of the effusions.  Healy22 and Lim23 also cultured bacteria from serous effusions.  Few studies have dealt with the effectiveness of antibiotics in treating chronic serous otitis.  Healy24 treated serous effusions with Trimethoprim / Sulfamethoxazole and found it beneficial.  He studied 50 patients over a four-week period.  All patients had CSOM for at least 12 weeks.  treated Group 18/25 resolved in the treatment group and 6 of 25 resolved in the control group (Chi Square p<0.001). Mandel, et al. in a prospective randomized double blind study found that "Amoxicillin treatment increases to some extent the likelihood of resolution".25  Older children can sometimes be taught to autoinflate their ears with air.  This devise has markedly decreased the tube insertion rate in older children who can be taught to use this device.

Steroid treatment is ineffective.  It should be remembered that many effusions are culture positive and severe intracranial complications can occur from an otitis media.  The use of an immunosuppressant in this setting warrants extreme caution.  Antibiotics are always given in conjunction with steroid therapy.  There is at least one lawsuit reported form the occurrence of CNS complications after prescribing steroids to treat chronic serous otitis.30

Several authors have studied the effectiveness of antihistamines/decongestants in the treatment of chronic serous otitis media.31,32,33  None have found a beneficial effect and behavioral changes in the children took place.  Although no study dealt with an allergic population, it is unlikely that the ear is a primary shock organ in many allergic children.34  Secondary effect of nasal allergy causing decreased nasal function can result in an increased incidence of otitis.

Myringotomy Tubes:
Tympanostomy tubes are only inserted for persistent CSOM refractory to medical treatment.  The children should have documented disease for 3 to 4 months and have been treated medically (i.e. with antibiotics or valsalva).  The most frequent complication of myringotomy tubes is a contamination infection.  These infections should always be treated with oral antibiotics and eardrops.  Foreign-Body Granulomas may form which can result in disturbing bleeding.35  These granulomas can be effectively treated in most patients with ear drops.  Perforations of the ear drum can occur in up to 2 to 4% of treated ears36, 37, however in our experience the incidence is less than 1%.  Cholesteatomas can also rarely occur.  Myringotomy tubes usually stay in place for 9 to 12 months although this length of time will vary with the typed of tube inserted.  Water precautions should be observed, however swimming with ear plugs in chlorinated pools has not been associated with infections in our patients.

The treatment of serous otitis media by adenoidectomy has been extensively studied in the literature.38  However, other studies have found a positive effect even when children with severe nasal obstruction were eliminated.42  Most studies evaluating children with nasal obstruction have found adenoidectomy to be beneficial 43, Bluestone (1986) It is obvious that there are many conflicting reports and a large randomized prospective study which controls for nasal obstruction is needed.  We agree with Snow(1980) that adenoidectomy is not indicated in most children who have CSOM without nasal symptoms.  Adenoidectomy should only be performed if the adenoid pad is felt to obstruct the eustachian tube either physically or functionally.

Acute Cholescent Mastoiditis:
The presence of an acute otitis media for longer than two weeks in association with a toxic child, post-auricular pain, swelling and a sagging posterior superior canal wall is diagnostic of acute cholescent mastoiditis.  This has the characteristic roentgenographic appearance of a cloudy mastoid with fuzziness and dissolution of the bony septae between air cells.  Once uniformly treated with surgery, this disease is currently treated medically unless complications arise or a subperiosteal abscess is present.  Treatment consists of intravenous antibiotics and wide myringotomy.  If a persistent fever develops or no improvement takes place a mastoidectomy is indicated. 45, 46, 47, 48, 49  The following have been identified as etiological organisms (Rosen 1986):

            Strep. pneumoniae                  3 patients
            Strep. Pyogenes                      2 patients
            H. influenza                             2 patients
            Staphylococcus                       1 patient
            Strep. viridins                          1 patient

Cholesteatoma:
A cholesteatoma is an epidermoid cyst in the middle ear and mastoid cavity.  The name cholesteatoma is a misnomer and is derived from the cholesterol crystals that are often found lining the sack.  The sac is usually secondarily infected and slowly expands causing bone erosion and destruction of the temporal bone that can result in deafness, facial paralysis, and intracranial complications.  The most common etiology is from a posterior superior or pars flaccida retraction pocket.  These retractions are associated with long-term middle ear negative pressure and chronic serous otitis media.  Other etiologies of cholesteatoma include iatrogenic causes, congenital epidermal skin rests and tympanic membrane perforations.  Cholesteatomas must be removed surgically to avoid progressive destruction of the ear.  Most often a mastoidectomy is required to accomplish this.  Cholesteatoma must be suspected in any chronic draining ear that fails to respond promptly to medical treatment.

Additional otic complications of otitis media and cholesteatoma:
Meningitis is the most common intracranial complication of otitis media.  Others include:  
            1)         Sigmoid Sinus Thrombosis
            2)         Cavernous Sinus Thrombosis
3)         Subdural Abscess
            4)         Brain abscess
            5)         Labyrinthitis
 

References:

1.      Meyerhoff, WL, Morizono, T, Wright, CG, et al.  Tympanostomy tubes and otic drops.  The Laryngoscope.  93:1022-1027, 1983.

2.      Brook I. Otitis media in children: A prospective study of aerobic and anaerobic bacteriology. The Laryngoscope. 89:992-997, 1979.

3.      Gebhart, D.E., Tympanostomy tubes in the otitis media prone child.  The Laryngoscope.  91:849-866, 1981.

4.      Balkany, et. al.  Middle ear effusions in neonates.  The Laryngoscope.  88:398-405, 1978.

5.      Schwartz, R., Rodriguez, W.J., and Schwartz, D.  Office myringotomy for acute otitis media:  Its value in preventing middle ear effusions.  Laryngoscope.  91:616-619, 1981.

6.      Beauregard, W.G..  Positional otitis media.  J. Pediatr., 79:294, 1971.

7.      Maynard, J.E., Fleshman, K., and Tschopp, C.F.  Otitis media in Alaskan Eskimo children:  Prospective evaluation of chemoprophylaxis.

8.      Lampe, R.M. and Weir, M.R.  Erythromycin prophylaxis for recurrent otitis media.  Clinical Pediatrics.  25:510-515, 1986.

9.      Perrin, M.M., Charney, E., MacWhinney, J.B. et. al. Sulfisoxazole as chemoprophylaxis for recurrent otitis media.  a double-blind crossover study in pediatric practice.  New England Journal of Medicine.  291:664-667, 1974.

10.  Ensign, P.R., Urbanich, E.M., and Moran, M.  Prophylaxis for otitis media in an Indian population.  Am J. Public Health 50:195-199, 1960.

11.  Gebhart, D.E., Tympanostomy tubes in the otitis media prone child.  The Laryngoscope.  91: 849-866, 1981.

12.  Gonzalez, C., Arnold, J.E., Wooky, E.A. et. al.  Prevention of recurrent acute otitis media:  Chemoprophylaxis versus tympanostomy tubes.  Laryngoscope.  96:1986, 1330-1334.

13.  Fiellau-Nikalajsen, M.  Tympanometry and secretory otitis media.  Acta Otolaryngol.  96(Suppl 394) 1983.

14.  Casselbrant, M.L., Okeowo, P.A., Flaherty, M.R., et. al.  Prevalence and incidence of otitis media in a group of preschool children in the United States.  IN Lim, D.J., Bluestone, C.D., Klein, J.O., et. al. (eds)  Recent advances in Otitis Media with Effusion.  Toronto, B.C.  Decker Inc.  1984.

15.  Kraemer, M.J., Richardson, M.A.and Weiss, N.S. et al:  Risk factors for persistent middle ear effusions.  JAMA 1983; 249;1022-1025.

16.  Black, N.  The aetiology of gule ear--A case-control study.  Int. J. Pediatr.  Otorhinolaryngol.  1985;9;121-133.

17.  Schwartz, R.H.  Duration of middle ear effusion after acute otitis media.  Pediatric Infectious Disease.  3:204-207, 1984.

18.  Teele, D.W., Klein, J.O. and Rosner, B.A.  Epidemiology of otitis media in children.  Ann. Otol.  Rhinol. and Laryngol.  89 (Suppl 68): 5-6, 1980.

19.  Stangerup, S.E. and Tos, M. Treatment of secretory otitis and pneumatization.  Laryngoscope  96:680-684, 1986.

20.  Liu, Y.S., et. al.  Chronic middle ear effusions:  Immuno chemical and bacteriological investigations.  Arch. Otolaryngology.  101:278-286, 1978.

21.  Palva, T.  et. al.  Immune complexes in middle ear fluid in chronic serous otitis media.  Ann. Otol.  Rhinol. Laryngol.  92:42-44, 1983.

22.  Healy, G.B., and Teele , D.W.  The microbiology of chronic middle ear effusion in children.  The Laryngoscopy.  87:1472-1578, 1977.

23.  Lim, D.J., et. al.  Otitis media with effusion cytological and microbiological correlates.  Arch. Otolaryngol.  105:404-412, 1979.

24.  Healy, G.B. and Smith, H.G.  Current concepts in the management of otitis media with effusion.  American Journal of Otol.  2:138-143, 1981.

25.  Mandel, E.M., Rockette, H.E. Bluestone, C.D., Paradise, J.L. and Nozza, R.F.  Efficacy of Amoxicillin with and without decongestant-antihistamine for otitis media with effusion in children.  NEJM  1987:316;432-437.

26.  Persico, M., Podoshin, L, and Fradis, M.  Otitis media with effusion:  A steroid and antibiotic trial before surgery.  Ann. Oto. Rhino. Laryngol.  87:191-196, 1978.

27.  Schartz, R.H.  Otitis media with effusion:  Results of treatment with a short course of oral prednisone or intranasal beclomethasone aerosol.  Otolaryngol Head Neck Surg.  89:386-391, 1981.

28.  Bluestone, C.D.  Pediatric Otolaryngology Conference, Memphis, TN  Oct 1985.

29.  Lambert, P.R.  Oral steroid therapy for chronic middle ear perfusion:  A double blind crossover study.  Otolaryngology-Head & Neck Surgery.  95:193-199, 1986.

30.  Grundfast, K.  Forum on Tonsillectomy and Adenoidectomy.  American Academy of Otolaryngology Conference.  San Antonio 1986.

31.  Cantekin, E.I., Mandel, E.M., Bluestone, C.D., et. al.  Lack of efficacy of a decongestant-antihistamine combination for otitis media with effusion (Secretory Otitis Media) in children.  N.E.  Journal of Medicine.  308:297-301, 1983.

32.  Chilton, L.A. and Skipper, B.E.  Antihistamine and Alpha-adrenergic agents in the treatment of otitis media.  Southern Medical Journal.  72:953-955, 1979.

33.  Randall, J.E., Hendley, J.O.,  A decongestant-antihistamine mixture in the prevention of otitis media in children with colds.  Pediatrics.  63:483-485, 1979.

34.  Bernstein, J.M., Lee, J., Conboy, K. Ellis, E. and Li, P.  The Role of IgE mediated hypersensitivity in recurrent otitis media with effusion.  The American Journal of Otology.  5:1983, 66-69.

35.  Hawke, M. and Keene, M.  Artificial eustachian tube-induced keratin foreign-body granuloma.  Arch. Otolaryngol.  107:581-583.

36.  Van Cauwenberge, P., Cauwe, F. and Kluyskins, P.  The long-term results of the treatment with transtympanic ventilation tubes in children with chronic secretory otitis media.  International Journal of Pediatric Othorhinolaryngology.  1:109-116, 1979.

37.  Luxford, W.M., and Sheehy, J.L.  Myringotomy and ventilation tubes:  A report of 1,568 ears.  Laryngoscope.  92:1293-1297.

38.  Snow, J.B. Role of tonsillectomy and adenoidectomy in the management of children with middle ear effusion.  Ann. Otol. Rhinol Laryngeal.  (suppl 74) 89:43-46, 1980.

39.  Roydhouse, N.  Adenoidectomy for otitis media with mucoid effusion.  Ann. Otol Rhinol.  Laryngology.  (Suppl 63)  89:312-315, 1980.

40.  Fiellau-Nikolajsen, M., Hojslet, P.E. and Felding, J.U. Adenoidectomy for eustachian tube dysfunction:  Long-term results from a randomized controlled trial.  Acta Otolaryngol.  Sup 386:129-131, 1982.

41.  Rynnel-Dagoo, B., Anlbom, A., and Schiratzki, H.  Effects of adenoidectomy A controlled two-year follow-up.  Ann of Otol. Rhinol. Laryngol.  87:272-278, 1978.

42.  Maw, R.  Chronic Otitis media with effusion and adeno-tonsillectomy--A prospective randomized controlled study.  International J. of Pediatric Otorhinolaryngology, 6:239-246, 1983.

43.  Elverland, H.H., Mair, I.W.,S., Haugeto, O.K., and Schroeder, K.E.  Influence of adenoid hypertrophy on secretory otitis media.  Ann. of Otol. Rhinol. and Laryngol.  90:7-11, 1981.

44.  Marshak, G. and Neriah, Z.B.  Adenoidectomy versus tympanostomy in chronic secretory otitis media.  Ann. Otol. Rhinol. Laryngology.  (Suppl 68)  89:315-318, 1980.

45.  Hawkins, D.B., Dru, D., House, J.W.  Acute mastoiditis in children:  a review of 54 cases.  Laryngoscope  93:568-72, 1983.

46.  Rosen, Arie., Ophir, D. and Marshak, G. Acute Mastoiditis:  A review of 69 cases.  Annals of Otology, Rhinology and Laryngology.  95:222-224, 1986.

47.  Hawkins, D.B. and Dru, D.  Mastoid subperiosteal abscess.  Arch.  Otolaryngol.  109:369-371, 1983.

48.  Rosen, A., Ophir, D. and Marshak, G.  Acute Mastoiditis:  a review of 69 cases.  Ann Otol Rhinol Laryngol  95:1986;222-223.

49. Ogle, J.W., and Lauer, B.A.  Acute Mastoiditis.  American Journal of Disease in Children.  140:1986; 1178-1182.