Effect of systemic antibiotics on the microbial flora of the external ear canal in hospitalized children.

The effect of antibiotic therapy and hospitalization on the external ear canal flora was investigated in 131 children. Fifty-eight percent of the patients receiving antibiotic therapy had Gram-negative bacilli or yeasts in their external ear canal, compared with 17% of the patients who were hospitalized for ten days or longer and only 3% of the patients who were hospitalized for short periods. Antibiotic therapy is the major factor in determining the colonization rate of the external ear canal with potentially pathogenic flora. Children under 1 year of age seem to be the most susceptible group to this shift of flora.

Necrotizing external otitis.

Necrotizing external otitis in an infant receiving cytostatic therapy for neuroblastema has been described. The disease is characterized by invasion and necrosis of the skin and cartilage of the external ear. P aeruginosa is the usual pathogen isolated in this infection. The disease should be suspected in infants with severe underlying conditions and who have external otitis that does not respond to local therapy. Vigorous antibiotic therapy and possible surgical intervention are indicated.

Bone conduction evaluation related to mastoid surgery.

The bone conduction threshold changes of 97 patients (100 ears) who underwent mastoid surgery were determined by comparing the last preoperative audiogram with the 1 year postoperative audiogram. Three types of mastoid surgery were evaluated: radical mastoidectomy, modified radical mastoidectomy, and intact wall atticomastoidectomy. The average three speech frequency preoperative bone conduction threshold was 17.4 dB (S.D. 11.5) in the radical mastoidectomy group, 10.1 dB (S.D. 9.6) in the modified radical mastoidectomy group, and 10.7 dB (S.D. 8) in the intact wall atticomastoidectomy group. The difference between the average three speech frequency preoperative bone conduction threshold of the radical mastoidectomy group differed significantly when compared to the modified radical mastoidectomy or intact wall atticomastoidectomy group. The postoperative average three speech frequency bone conduction threshold did not change significantly following the three surgical procedures evaluated.

Gas composition and pressure in the middle ear: a model for the physiological steady state.

The gas contents of the physiological middle ear periodically cycle through two phases in steady state. During phase I, the eustachian tube is shut and the middle ear gas space is effectively closed. Gas is absorbed or produced at the mucosal surface, and the total pressure changes correspondingly. During phase II, which is of very short duration, the eustachian tube opens, a bolus of gas passes between the middle ear and the nasopharynx, and the total pressure in the middle ear rapidly adjusts to that in the nasopharynx. Since nasopharyngeal pressure fluctuates in time, so does the pressure in the middle ear. The effect of these pressure changes is to produce a level of ventilation in the middle ear, which depends on a combination of three parameters: the volume of the middle ear, multiplied by the mean amplitude of pressure variations in the nasopharynx, divided by the mean elapsed time between successive eustachian tube openings. Assuming steady-state conditions, the composition of middle ear gas can be computed and is predicted to range from PN2 = 621, PO2 = 46, PCO2 = 46, PH2O = 47 mm Hg in the case when nasopharynx fluctuations are small, to a match with nasopharyngeal gas composition, when the fluctuations are large.

Malignant external otitis: The diagnostic value of bone scintigraphy.

Technetium99m Methylene Diphosphate bone scintigraphy (BS) of the skull was performed in three patients with malignant external otitis (MEO). Pathological uptake of the radioisotope in the mastoid region was found during the early stages of MEO updating radiologic findings. The extent of the radioisotope accumulation during the early stages of MEO indicates that the actual tissue damage exceeds the clinical estimation. The follow-up BS findings correlate well with the clinical course of MEO indicating either healing or extension to the base of skull.

Malignant external otitis: early histopathologic changes and pathogenic mechanism.

The histopathologic changes during the early stage of malignant external otitis (MEO) were studied in two patients, one a non-diabetic. The specimens were obtained by an en bloc excision of the diseased tissue of the external ear canal through a retroauricular approach. The most prominent histologic features of the early stage of MEO consist of a thick layer of almost acellular, partly degenerated, collagen extending from the cartilage into the dermis, which most likely existed prior to the penetration of the microorganism. This finding supports our concept that MEO is a disease which develops as a results of invasion of opportunistic organisms into tissue previously devitalized, probably due to vascular compromise and that these latter features constitute the basic mechanism of the entire disease process.

Fourth pharyngeal pouch sinus.

This is the first description and documentation of an extremely rare developmental anomaly of the pharyngeal apparatus in a 15-year-old female. The clinical, radiological, histological, and anatomical findings indicated that the anomaly originated in the pharyngeal fourth pouch. It presented as a recurrent lateral neck abscess which was due to a paratracheal sinus. This sinus penetrated the larynx and after a translaryngeal course ended in the pyriform sinus. It was caudad to the superior laryngeal nerve and external to the recurrent laryngeal nerve. Its penetration into the larynx at the cricothyroid joint region could serve as a useful surgical landmark.

Bone conduction changes following successful tympanoplasty type I.

Pre and one year postoperative bone conduction (b.c.) thresholds were compared for 50 ears of 48 patients, ranging in age from 14 to 42 years, in whom successful tympanic grafts resulted in at least an average improvement of 10 db for 500 to 4000 Hz. While pre and postoperative data are included for all ears and test frequencies, significant BC improvement is seen only at those frequencies, in each case, where the pre-op BC thresholds were worse than 10 db. Normal pre-op BC thresholds cannot show substantial improvement because of audiometric limitations. The amount of BC shift at each frequency for those with pre-op BC thresholds that were subnormal averaged 6 db at 500 Hz, 13.3 db at 1000 Hz, 13.8 db at 2000 Hz and 9 db at 4000 Hz, all highly significant statistically. There were no significant postoperative BC shifts related either to duration of the disease process, length of postoperative period before final test (all were more than one year) or whether the surgical procedure was tympanoplasty type I or myringoplasty.

Transient pressure changes in the middle ear.

Transient increases in total pressure in the ear (1) during sleep, after hypoventilating in a supine position with a closed eustachian tube, and (2) after the partial pressures in middle-ear gas are lowered by a total pressure decrease and the eustachian tube is voluntarily maintained closed can be accounted for quantitatively on the basis of the standard mucosal gas exchange model and the following data: (1) partial pressures in tissue: pN2* = 573 mm Hg (7621 decaPascals [daPa]), pO2* = 40 mm Hg (532 daPa), pCO2* = 46 mm Hg (612 daPa), and pH2O* R = 47 mm Hg (625 daPa); (2) partial pressures in the nasopharynx: pN2' = 566 mm Hg (7528 daPa), pO2' = 120 mm Hg (1596 daPa), pCO2' = 27 mm Hg (359 daPa), and pH20' = 47 mm Hg (625 daPa); (3) a middle-ear gas space of 2 x 10(-5) m3; (4) an absorption rate for nitrogen, when the partial pressure difference is 1 atm, of 3 x 10(15) molecules per second; and (5) mucosal absorption rates for oxygen and carbon dioxide 1.8 and 34 times larger, respectively, than for nitrogen.

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.

Theoretic analysis of middle ear gas composition under conditions of nonphysiologic ventilation.

As gas flows in and out of the nasopharynx, the pressure in that region fluctuates. It drops below or rises above atmospheric pressure, which is itself not constant but is subject to changes in altitude and weather. Such pressure changes in the nasopharynx produce a pumping of gas into and out of the middle ear. The net amount of middle ear gas transferred from or to the nasopharynx will, component for component, in steady state exactly equal the amount of middle ear gas transferred to or from the microcirculation by means of diffusional absorption by (or release from) the mucosa. In the case of a permanently patulous eustachian tube, a single parameter, characteristic of the rate of ventilation through the open eustachian tube, is found to determine the gas composition in the middle ear, whereas in the case of a middle ear ventilated by tympanostomy, two rate-of-ventilation parameters, one for gas flow through the ventilation tube and one for flow through a periodically open eustachian tube, determine the steady state gas composition. A high rate of ventilation favors absorption of oxygen and venting of carbon dioxide from the middle ear in both cases.

Pressure chamber tympanometry in diving candidates.

The currently recommended examination for diving fitness ascertains middle ear autoinflation ability only under surface pressure conditions. The purpose of our study was to document and quantify middle ear pressure equalization failure during simulated dives among diving candidates who had otherwise met the otologic criteria for diving fitness. Forty-two candidates for regular naval diving activity were included in the study. Tympanograms of both ears at 1 and 1.1 absolute atmospheres (ATA) were taken inside a pressure chamber with the subjects in two positions: seated and supine. At a pressure of 1 ATA, type A tympanograms were found in all 84 ears examined. At a pressure of 1.1 ATA, with subjects in the upright position, 19 (22.9%) of the ears had type C and 2 (2.4%) type B tympanograms, while with subjects recumbent during descent, 6 of the ears (7.2%) had type C and 7 (8.4%) type B. Our results suggest that successful autoinflation at surface ambient pressure does not necessarily reflect middle ear pressure equalization ability during descent in a dive.

Micromethod for determination of middle ear gas composition.

This is a microchromatographic method for simultaneous determinations of O2, N2, CO2 and N2O in gas samples of 40-100 microliters. A Packard 836 U gas chromatograph with a thermal conductivity detector and helium gas as carrier was used. The combination of Porapak and 5A molecular sieve column system was found adequate and is described in detail. The fidelity of this method was proved by a high constancy of the retention time, the linearity of the response and the reproducibility of results. The present method proved to be reliable for determination of all middle ear gases in man and experimental animals during general anesthesia with N2O.

Gas scavenging during bronchoscopy under general anesthesia.

Prevention of exposure of the endoscopist to high levels of anesthetic gases during bronchoscopy was attempted experimentally in dogs by a scavenging system. Results were compared with exposure during the conventional technique of anesthetic gas administration for clinical bronchoscopy using the rigid open ventilating bronchoscope. The scavenging system consisted of a vacuum pump applied to the open ventilating rigid bronchoscope sidearm connection during intratracheal administration of nitrous oxide, , oxygen, and halothane gas mixture. Gas samples were taken from the trachea, the proximal end of the bronchoscope, and the endoscopist's breathing zone, and analyzed by gas chromatography. Findings indicate that halothane anesthesia for bronchoscopy administered by conventional techniques is a source of air pollution in the operating room and exposes the endoscopist to subanesthetic levels of halothane that may affect psychomotor functioning. The use of the gas scavenging system lowered the concentrations of halothane and nitrous oxide at the endoscopist's breathing zone to a level at which inhalation for short periods has no clinical effects, while the concentrations of the anesthetics and oxygen in the trachea were maintained at a satisfactory level.

Middle ear gas composition during nitrous oxide-oxygen ventilation.

The middle ear gas composition during 180 minutes ventilation with nitrous oxide-oxygen mixture was determined in 12 mongrel dogs. The mean relative concentration of N2O in the middle ear (ME) rose to 12,26.4 and 29.3% after 60, 120 and 180 minutes respectively. During this period, the relative concentration of N2 dropped from a mean of 83.2% in the air-ventilated dogs to 54.8%, without an essential change in the concentrations of O2 or CO2. The elimination of N2O from the ME during 30 minutes of postanesthetic ventilation with O2 was incomplete, an average of 11.4% N2O remaining in the ME. At the same time, the mean relative concentration of O2 reached 19%, higher than the O2 relative concentration normally present in the ME. The results indicate that gas diffusion may occur across the ME mucosa for N2O as well as for O2, producing selective changes in the middle ear gas composition.

Peripheral blood T and B lymphocyte subpopulations in Bell's palsy.

A prospective clinical, virological and immunological study was performed on 25 consecutive Bell's palsy (BP) patients. Multiple cranial nerve involvement was found in 15 patients. A significant decrease in the peripheral blood T lymphocyte percentage as well as an increase in B lymphocyte percentage (p less than 0.001) were found in 13 of the BP patients during the first 24 days from the clinical onset of the paralysis. No correlation was found between the peripheral blood lymphocyte subpopulations and the patient's age, sex, degree of paralysis or recovery rate. No changes were detected in the levels of immunoglobulins (IgG, IgM), complement (C3, C4) and antiviral antibodies to herpes simplex and zoster, EBV, cytomegalic virus, adenovirus, influenza and mumps. The clinical and immunological data of BP show a similar pattern to those of Guillain-Barre syndrome suggesting that BP may be an antoimmune demyelinating cranial polyneuritis which may be caused by a preceding viral infection.

Bilateral tension pneumothorax during pediatric bronchoscopy (high-frequency jet injection ventilation).

Bilateral tension pneumothorax complicating high-frequency jet injection ventilation during rigid open bronchoscopy for foreign body removal in a 3-year-old child is reported. Subcutaneous emphysema, bradycardia and low voltage of the QRS complex were the presenting symptoms. Disparition of heart dullness by percussion was the most suggestive clinical sign while auscultation of the breath sounds was not conclusive. It is stressed that tension pneumothorax is a potential life-threatening complication of high-frequency injection ventilation and should be promptly considered in any case of persistent cardiac deterioration during pediatric bronchoscopy.

Surgical management of congenital supraglottic lateral saccular cyst.

A case is described of a neonate with a rare, congenital, supraglottic, lateral, saccular cyst presenting with stridor and asphyxia. Repeated needle aspirations of the cyst failed to provide sustained clinical improvement. CT scans proved useful for precise intralaryngeal location of the cyst and planning of the surgical excision. At two months of age the cyst was successfully excised by a paramedian thyrotomy via an external cervical approach, avoiding tracheostomy.

Bone scintigraphic diagnosis in acute frontal sinusitis.

The diagnostic value of Technetium 99m Methylene Diphosphate bone scintigraphy was evaluated in 21 patients, 10 of them with acute frontal sinusitis and a "fluid level" on sinus radiography. Pathologic accumulation of the radioisotope over the region corresponding to the diseased frontal sinus was observed in 9 of these 10 patients, 5 of them having a marked accumulation. The patients with marked accumulation of the bone-seeking radioisotope had a more severe clinical course of the disease than those who had a moderate or no accumulation of the radioisotope. Marked accumulation of the radioisotope was also found in a patient with "inflammatory pseudotumor of the orbit". The radioisotope did not accumulate over the frontal sinus of patients with mucosal swelling or cellulitis of face, or in control patients with mastoid disease. Based on our findings, we recommend bone scintigraphy be performed routinely for diagnosis of acute frontal sinusitis. A marked accumulation of Tc99m MDP indicates inflammatory metabolic changes of the sinus bony walls, predicting a severe clinical course and the necessity of aggressive treatment.

Antigenic determinants detected on adenoid lymphocytes.

This study was undertaken to detect the antigenic determinants expressed by adenoid lymphocytes. For this purpose, adenoid and peripheral blood lymphocytes obtained from the same patient were subsequently tested with human and hetero antisera. The research was based upon microlymphocytotoxicity where the various lymphocyte subsets were incubated with the antiserum and complement. The reactions were scored by the dye exclusion technique. The results indicated that: 1) compared with peripheral blood, the expression of the major histocompatibility gene products is enhanced by adenoid lymphocytes; 2) adenoid T lymphocytes express DRw antigens. These antigens were thought to be restricted to B lymphocytes and macrophages but have later been detected in T lymphocytes activated in vitro. Thus, lymphocytes derived from hypertrophied adenoids may simulate a culture activated in vivo; 3) because of their higher sensitivity to antibodies and complement-mediated cell lysis, adenoid lymphocytes may be useful in detecting minor histocompatibility gene products and differentiation antigens. It is concluded that adenoids represent a highly active lymphoid organ probably actively participating in the host's immunological defence mechanism.