Acute Middle Ear Infection Research Articles

Severe acute middle ear infections: Microbiology and treatment

The database at the ENT-Department, Aarhus University Hospital describing the specific local flora of acute otitis media (AOM) and acute mastoiditis (AM) in Aarhus County has become the key element in securing a rational and specific antibiotic treatment. We present our data concerning AOM, mastoidismus and AM. Our purpose is to determine (I) clinical presentation, (II) causative pathogens, (III) resistance patterns, (IV) type of antibiotic treatment, and (V) accuracy of the antibiotic treatment. Patients under the age of 18 years, treated for AOM with extensive affected well-being and AM, at the ENT-Department, Aarhus University Hospital during 3 years from January 2001 to December 2003. A total of 106 patients were identified. Sixty-seven patients with AOM and 39 patients with AM. The overall bacterial flora found is dominated by S. pneumococci all 100% susceptible to penicillin. However, Staphylococcus aureus is the primary bacterial pathogens cultured from patients treated with preadmission antibiotics. If a specimen from an AOM patient is obtained after the initiation of antibiotic treatment one should consider the possibility of the culture found being a result of the initial led treatment and not the causative AOM pathogen. Our data suggest that a restricted use of antibiotics in children with AOM may be associated with a higher incidence of acute mastoiditis. Significant higher leucocytes count and CRP are found in the acute mastoiditis group compared to the AOM group.

Gastroesophageal reflux disease: Its importance in ear, nose, and throat practice

Gastroesophageal reflux disease (GERD) has been implicated in various extra-gastroesophageal diseases, especially in the upper and lower airways (atypical GERD). The objective of the present study was to determine the frequency of gastroesophageal and extra-gastroesophageal symptoms in pediatric patients with GERD and their response to the general treatment. A retrospective study was conducted on 45 children of both sexes aged 3 months-12 years with GERD diagnosed by clinical examination and 24h single-channel pHmetry. The gastroesophageal and extra-gastroesophageal symptoms, the treatment instituted and the response of the patients to the latter were determined. Five symptomatologic groups were identified: gastroesophageal (51.11%), pulmonary (recurrent pneumonia, 40%, and bronchial asthma, 46.67%), chronic cough (64.44%), rhinologic (chronic nasal obstruction, 68.88%, nasal secretion, 55.55%, and nose itching, 46.66%), and pharyngo-otologic (recurrent acute middle ear infection, 35.56%, and recurrent tonsillitis, 24.44%). The response to treatment (antireflux drugs, antiallergic drugs, and surgical procedures) resulted in cure in 24 patients (53.34%), while 21 continued to be symptomatic. The cure rate was 69.56% for the gastroesophageal group, 100% for the recurrent pneumonia group, 80.95% for the bronchial asthma group, 68.96% for the chronic cough group, 83.87% for the chronic nasal obstruction group, 80% for the nasal secretion group, 85.71% for the nose itching group, 100% for the recurrent acute middle ear infection group, and 90.90% for the recurrent tonsillitis group. Total treatment time was 1.8 times longer for the remission of extra-gastroesophageal symptoms. Exclusive antireflux treatment promoted full remission of the otorhinolaryngologic symptoms in 38.89% of patients (nasal-41.17%, recurrent acute middle ear infection-12.5%, and recurrent tonsillitis-18.18%). GERD can cause otorhinolaryngologic symptoms in children and remission of these symptoms can be obtained with antireflux therapy.

Analysis by cDNA microarrays of altered gene expression in middle ears of rats following pneumococcal infection

Objective: Streptococcus pneumoniae is the most common pathogen in otitis media. Infection of the middle ear with S. pneumoniae potentiates development of thick effusion in the middle ear which frequently causes hearing loss and communication disorders in children. What has changed immediately in the middle ear cleft following pneumococcal infection is extensively studied and characterized but what has changed ever after remains elusive. The purpose of this study is to explore the cellular and molecular basis that remains on a longer time after acute pneucmococcal middle ear infection and potentiates development of thick effusion in the middle ear. Methods: 12 rats were intrabullarly inoculated with pneumococcus at 2.5×10 6 CFU/ear and profiles of gene expression in the middle ear were examined by cDNA microarrays in combination with reverse transcription-polymer chain reaction (RT-PCR) 6 weeks after infection while the morphologic changes in middle ear were simultaneously characterized by histopathologic techniques. Twelve rats receiving phosphate-buffered saline (PBS) served as controls. Results: it demonstrated that pneumococcus infected ears had the expression of the following genes at a high level compared to the controls: mitogenic signaling proteins (mitogen-activated protein kinase [MEK1 and MEK2], helix–loop–helix transcriptional regulators (Id3 and Id1), ion channels (sodium channel beta 1 and sodium channel 2), and mucin glycoproteins ( Muc2 and Muc5). The morphology demonstrated a thickened mucosa and submucosa with increased expression of macroglycoconjugates compared to the controls. Conclusion: the expression of several genes remains high even after the acute episode of pneumococcal otitis media has been resolved. The up-regulated expression of these genes may serve as the basis for the development of thick effusion and mucous cell metaplasia/hyperplasia once it is complicated with other factors such as dysfunction of the Eustachian tube.

Histopathologic differences due to bacterial species in acute otitis media

Objective: To compare selected features of histopathology in acute otitis media caused by various bacteria and examine potential differences due to bacterial species, as well as possible correlation to experimental and human clinical findings. Methods: Rat models of acute otitis media caused by Streptococcus pneumoniae ( MC), non-typeable or type b Haemophilus influenzae ( NTHI/ HIB) or Moraxella catarrhalis ( MC) were studied longitudinally up to 6 months after bacterial challenge. Findings related to dynamics of goblet cell density, modeling and remodeling of bone tissue structures and polyp, as well as fibrous adhesion formation and persistence are presented. Results: Middle ear goblet cell density progressed to peak 2 weeks after bacterial inoculation, thereafter gradually normalizing. However, density and accordingly middle ear secretory capacity was still significantly increased after 6 months in all bacteria, except MC. The HI species induced the highest increase. Initial osteoresorption was followed by massive osteoneogenesis, progressing to a peak after 2–3 months, followed by some degree of normalization, concurrently classic remodeling. Primarily SP, but also the HI species induced more new bone formation than MC. Mucosal polyp and fibrous adhesion formation occurred regardless of bacterial species. Most polyps appeared in the early phases and the HI species induced formation of more polyps and adhesions than the other bacteria. Conclusion: Acute middle ear infection with the Haemophilus species induce the highest increase of mucosal secretory capacity, lasting for at least 6 months after the acute incident. Thus, a subsequent development of secretory otitis media seems more likely following infection with these bacteria. Equivalently, mucosal scarring observed as polyp and fibrous adhesion formation was more severe following Haemophilus infection. S. pneumoniae induced the most marked changes of bone tissue structures, seen as initial osteoresorption and subsequent osteoneogenesis. Overall, infection with M. catarrhalis induced the mildest changes.

Prevention of acute mastoiditis: fact or fiction?

Acute mastoiditis is the most common complication of acute otitis media (AOM). In recent years routine antibiotic treatment for acute middle ear infections was questioned and even abandoned in some countries. The goal of our study was to investigate the influence of antibiotic treatment on the occurrence and clinical outcome of acute mastoiditis and to analyze the bacteriological findings. A retrospective case record study of 48 patients with 50 episodes of acute mastoiditis hospitalized at our tertiary-care center between 1992 and 1999 was performed. Twenty-three patients (48%) received antibiotic treatment before admission whereas 25 (52%) did not. The group of patients without antibiotic pretreatment were younger (mean, 6 years) than patients with antibiotics (mean, 18 years) and their referral was delayed. The most common isolated single pathogen was Streptococcus pneumoniae. All pneumococci were sensitive to penicillin. Acute mastoiditis may be the first clinical sign of a middle ear infection, especially in very young children. Adequate antibiotic pretreatment cannot invariably prevent the development of acute mastoiditis even in the absence of penicillin resistant pathogens.

Middle Ear Secretory Capacity After Acute Otitis Media Caused by Streptococcus pneumoniae , Moraxella catarrhalis , Non-typeable or Type B Haemophilus influenzae : A comparative analysis based on goblet cell density

To investigate whether the type of bacteria is correlated with an increase in goblet cell density during and after acute otitis media, we inoculated the middle ear of 25 rats with either Streptococcus pneumoniae , Moraxella catarrhalis , non-typeable or type b Haemophilus influenzae . Mucosal goblet cell density was determined by a whole-mount method on days 4, 8, 16, 60 and 180 post-inoculation. The goblet cell density was increased on all days of sacrifice, employing either bacteria, except M. catarrhalis 6 months after the acute incident. Type b H. influenzae induced the highest increase, followed by non-typeable H. influenzae , S. pneumoniae and M. catarrhalis . The mucosal area containing goblet cells was enlarged on all examination days, employing either bacteria. We conclude, that mucosal secretory capacity is highly increased during and up to 6 months after acute middle ear infection caused by either bacteria, conceivably predisposing a subsequent development of secretory otitis media. The results indicate that type b H. influenzae seems to be the bacteria most likely to induce a subsequent secretory condition.

Surfactant protein A in rabbit sinus and middle ear mucosa.

In the present study, pulmonary surfactant protein A (SP-A) messenger RNA (mRNA) and protein were characterized in adult rabbit middle ear and maxillary sinus. Fifteen adult rabbits were used for the study: 6 with evidence of acute middle ear infections and maxillary sinusitis, 6 with infections that were successfully treated with tetracycline, and 3 that were pathogen-free. We detected SP-A mRNA in maxillary sinus and middle ear tissues by Northern blot analysis and reverse transcriptase-polymerase chain reaction (RT-PCR). The RT-PCR also revealed the presence of SP-B and SP-C mRNA in middle ear and sinus tissues. We detected SP-A protein, of molecular weight approximately 29 and 70 kd, in middle ear and sinus tissues by immunoblot analysis. Unlike the SP-A protein present in the lung, the molecular weight of the SP-A protein present in the middle ear and paranasal sinus was not altered by digestion with an enzyme that cleaves N-linked carbohydrates. Immunostaining and in situ hybridization showed that SP-A protein and mRNA, respectively, were present in surface epithelial cells of the middle ear and in epithelial cells of submucosal glands in sinus tissues. These data provide the first evidence of the presence of pulmonary surfactant proteins in the paranasal sinuses and confirm previous reports of SP-A in the middle ear epithelium.

Bone modeling dynamics in acute otitis media.

A number of middle ear diseases are associated with pathologic bone modeling, either formative or resorptive. As such, the pathogenesis of a sclerotic mastoid has been controversial for decades. Experimental studies on acute middle ear infection have shown varying degrees of both osteoresorption and osteoneogenesis. This study presents data on the dynamics of bone modeling in a rat model of acute pneumococcal otitis media, studied longitudinally from day 1 through 6 months after inoculation. Qualitative, as well as quantitative histopathology revealed initial osteoresorption, followed by increasing apposition of new bone in the middle ear cavity, initiated at the outer periosteum. Measured bone thickness in four anatomically distinct locations peaked 3 months after inoculation, followed by some degree of normalization. However, bone thickness was still massively increased 6 months after the acute incident. Except in perilymphatic spaces of the otic capsule, resorptive and formative activity were found in all bone tissue structures surrounding the middle ear cavity, including the bony external auditory canal and the ossicles. These findings may support the existence of a perilymphatic barrier of specialized bone and suggest that even a single episode of acute infection may alter properties of ossicular chain conduction. The authors conclude that acute otitis media is accompanied by massive and progressing net osteoneogenesis, already evident at 3 days and peaking 3 months after inoculation, followed by some degree of normalization. This is conceivably in support of the environmental theory of mastoid pneumatization, claiming inflammatory disease as the cause of a sclerotic mastoid.

Acute middle ear infection in small children: a Bayesian analysis using multiple time scales.

The study is based on a sample of 965 children living in Oulu region (Finland), who were monitored for acute middle ear infections from birth to the age of two years. We introduce a nonparametrically defined intensity model for ear infections, which involves both fixed and time dependent covariates, such as calendar time, current age, length of breast-feeding time until present, or current type of day care. Unmeasured heterogeneity, which manifests itself in frequent infections in some children and rare in others and which cannot be explained in terms of the known covariates, is modelled by using individual frailty parameters. A Bayesian approach is proposed to solve the inferential problem. The numerical work is carried out by Monte Carlo integration (Metropolis-Hastings algorithm).

Middle ear fluid concentrations of amoxicillin after large dosages in children with acute otitis media.

Middle ear fluid concentrations of amoxicillin after large dosages in children with acute otitis media.

Model-based estimation of the excess fraction (attributable fraction): day care and middle ear infection.

The methods of adjustment for estimation of the excess fraction (EF), or attributable fraction, based on conventional and dynamic (or regressive or autoregressive) logistic regression modelling in a cohort study for a disease with recurrent episodes are considered. Throughout the paper, the computation of estimates with corresponding confidence intervals is illustrated in a cohort study associating the incidence of acute middle ear infection (acute otitis media) with type of day care in northern Finland. The incidences of at least one episode and at least three episodes as well as the total number of episodes during the first two years of life are considered. In our example, the estimates obtained from the dynamic model appear to have smaller standard errors since the dynamic model effectively utilizes the time-dependency of the covariates.

COMPLICATIONS OF NITROUS OXIDE ANESTHESIA FOR EAR SURGERY

SUMMARY Middle ear pressure measured in surgical patients has been as high as 450 mm H2O after only 15 to 20 minutes of nitrous oxide inhalation. This increase in pressure bulges the eardrum outward and complicates otologic procedures such as replacement of the tympanic membrane or closing of a perforation. Increased middle ear pressure can also contribute to postoperative pain, delirium, nausea, and vomiting. Furthermore, discontinuation of nitrous oxide brings a decrease in middle ear pressure that can displace a tympanic graft. For all these reasons, many authors suggest avoiding nitrous oxide anesthesia for surgical procedures on the middle ear: tympanoplasty, stapedectomy, ossicular repositioning, and mastoidectomy. Finally, the possible lingering presence of nitrous oxide within the middle ear makes it wise to avoid nitrous oxide for all surgical patients who have middle ear disease and abnormalities of the eustachian tube. Because of the possibility of tympanic membrane rupture during or after nitrous oxide anesthesia, specific information concerning previous otologic surgery should be obtained prior to anesthesia. Patients especially vulnerable are those with acute or chronic middle ear infections or inflammation or scarring of the nasopharynx. Techniques that promote rapid recovery from anesthesia and the early return of pharyngeal reflexes facilitate venting of middle ear gas through the eustachian tube. The clinician can prevent the diffusion problem encountered with nitrous oxide by using a mixture of oxygen and air as the vaporizing vehicle for a more potent halogenated agent. If the anesthetist wants to use nitrous oxide, however, the lowest concentration feasible (50% or less) should be combined with a more potent agent for the shortest period possible and then discontinued as soon as the level of anesthesia is adequate.

Late Development of Lateral Sinus Vein Thrombosis

The incidence of lateral sinus vein thrombosis has been reduced by the use of antibiotics, but it is still a major complication of middle ear disease. Patients without active acute or chronic middle ear infection, however, develop this deadly complication. CT scan is helpful in diagnosis, but mostly the final diagnosis is made by surgical exploration. A case of a 23-year-old patient who developed lateral sinus vein thrombosis without an active middle ear disease is presented. The pertinent literature is discussed.

Intracranial suppuration 1968-1982--a 15 year review.

The CT scanner and the recognition of anaerobic organisms has altered the investigation and management of intracranial suppuration. Improved treatment of acute and chronic middle ear infection has also occurred. A 15 year retrospective review was undertaken to assess the effects of these changes. The ears and sinuses were confirmed as the major source of intracranial suppuration (69%) although initial presentation to ENT surgeons was less common (14%). Ear complications occur in childhood and in the fifth and sixth decades; sinus complications predominantly in the second and third decades. The incidence of sinus infection appears to be rising. With the introduction on the CT scanner cerebral abscess mortality declined from 27.5% to 6.5% and subdural abscess mortality halved. The introduction of metronidazole contributed to a drop in mortality. The use of the CT scanner and more accurate antibacterial treatment, including metronidazole, gives hope for a more successful outcome than was previously possible.

Complications of acute middle ear infections.

Although acute mastoiditis and intracranial otogenic complications occur less frequently in our time than in the preantibiotic period, the disease is nevertheless still a rather severe medical problem. Its mortality rate remains relatively high and the severity of its symptoms is often underrated or misinterpreted by the inexperienced physician. On the basis of some personal clinical observations made during the last decade, attention has been drawn to the most common intracranial and extracranial otogenic complications in adults and children. It may therefore be concluded that otitis media must still be considered a dangerous disease, necessitating fundamental knowledge of its underlying pathology, which provides a basis of early correct diagnosis and adequate intensive therapy.

Tuberculous otitis media

A case of tuberculous otitis media is being reported. It is a rare infectious disease and remains undiagnosed or confused with other acute or chronic middle ear infections, if appropriate diagnostic studies are not performed. Due to the confusion in the diagnosis of this disease, mild to severe complications develop early.

Aminoglycoside antibiotics in the treatment of otologic infections.

Aminoglycoside antibiotics can be used successfully in the treatment of otologic infections caused by gram-negative bacteria. They can be particularly valuable, sometimes in combination with a beta-lactam antibiotic such as carbenicillin, in malignant external otitis, acute middle ear infections caused by gram-negative organisms, and central nervous system complications of cholesteatomas. On the basis of susceptibility tests and of the pharmacology of these drugs, we administer appropriate therapeutic doses of one of the following antibiotics: kanamycin, gentamicin, tobramycin, or amikacin. All of these drugs may be ototoxic and nephrotoxic.

Microbiological evaluation of acute otitis media (author's transl)

The evaluation of isolated bacteria from patients with acute otitis media varies among investigators, and to elucidate this problem microbiological investigations and a study on the related host defense mechanism were carried out in a total of 183 out-patients between December 1977 and December 1978.Middle ear fluids were aspirated when the patients were first seen and again 24 hours later.The following results were obtained:1) Sole strain was isolated in 134 cases.On the initial investigation, Haemophilus influenzae was the most frequent organism grown from the fluids in children under 5 years of age. Staphylococcus aureus (S. aureus) was predominantly isolated from the patients older than 6 years of age.The predominant organisms except S. aureus isolated in the first visit altered to S. aureus in 20. 9% of the patients in the reexamination after 24 hours.2) Mixed isolates were found in 49 cases.It was observed that in many cases the mixed isolates including both low and high pathogenic strains in the first examination had changed into the single strain high pathogenicity 24 hours later. An increasing frequency of low pathogenic organisms was remarkable particularly in older patients.3) Nitroblue-tetrazolium test;A significant increase in number and percentage of NBT-positive neutrophils were noted in patients with leukocytosis (104/mm3 or more) and fever (above 37.5dC), and notably in patients with S. aureus infection.4) Serum immunoglobulins;It was impossible to obtain the satisfactory result on the correlation between each immunoglobulin (IgG, IgA and IgM) and acute middle ear infection.5) Our conclusion was that the isolates from middle ear fluids are varied with the passage of time and the relationship between host defense mechanism and parasite.

Acute gram-negative bacillary infections of middle ear and mastoid.

Thirty-three patients with acute purulent otitis media and mastoiditis caused by Gram-negative bacilli are presented. The main features of the disease include: predilection for young male infants, a high rate of complications that include sepsis, mastoiditis and osteomyelitis of the base of the skull. Patients that are diagnosed early respond well to drainage and ventilation of the infected middle ear combined with in vitro effective antibacterial therapy. Patients that receive prior inappropriate antibacterial therapy tend to have prolonged courses and require mastoid surgery. It is suggested that early myringotomy and bacterial cultures be performed in all patients with acute middle ear infections.

The etiology of chronic otitis media.

Various current theories regarding the aetiology of chronic otitis media are considered in detail. The concept that it originates from an acute middle ear infection no longer appears tenable. Recent experimental work has demonstrated the role of invading skin causing invasive osteitis. It is postulated that in some instances osteitis may follow erosion of the metal skin and proceed to widespread chronic disease of the temporal bone. The important difference between obstruction and inadequacy of the Eustachian tube and the significance of the latter in chronic middle ear disease is emphsized. The Eustachian mechanism of cholesteatoma formation may best be studied by observing the development of retraction pockets following tympanoplasty.