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Biomedical subjects

James D Kellner

Publications and source records attributed to James D Kellner.

16 recordsLinked to original sources

Respiratory syncytial virus bronchiolitis.

Respiratory syncytial virus, the most common cause of bronchiolitis, is the leading cause of infant hospitalization in developed countries and accounts for substantial mortality and morbidity in developing countries. Children at increased risk of developing severe bronchiolitis are those <6 weeks of age, those born prematurely and those with an underlying cardiopulmonary disorder or immunodeficiency. Approximately 80% of cases occur in the first year of life. By two years of age, virtually all children have been infected by at least one strain of the virus. Classically, respiratory syncytial virus bronchiolitis manifests as cough, wheezing and respiratory distress. The mainstay of treatment is supportive care, consisting of adequate fluid intake, antipyretics to control fever and use of supplemental oxygen if necessary. Frequent and meticulous hand-washing is the best measure to prevent secondary spread. Treatment of respiratory syncytial virus bronchiolitis beyond supportive care should be individualized. Palivizumab has been shown to be effective in preventing severe respiratory syncytial virus bronchiolitis in high-risk children when given prophylactically. In the majority of cases, the disease is usually self-limited. The mortality rate is <1% and occurs predominantly in children at high risk for severe disease.

Adrenal Cortex Hormones↗

Empirical validation of guidelines for the management of pharyngitis in children and adults.

CONTEXT: Recent guidelines for management of pharyngitis vary in their recommendations concerning empirical antibiotic treatment and the need for laboratory confirmation of group A streptococcus (GAS). OBJECTIVE: To assess the impact of guideline recommendations and alternative approaches on identification and treatment of GAS pharyngitis in children and adults. DESIGN, SETTING, AND PARTICIPANTS: Throat cultures and rapid antigen tests were performed on 787 children and adults aged 3 to 69 years with acute sore throat attending a family medicine clinic in Calgary, Alberta, from September 1999 to August 2002. Recommendations from 2 guidelines (those of the Infectious Diseases Society of America and of the American College of Physicians-American Society of Internal Medicine/American Academy of Family Physicians/US Centers for Disease Control and Prevention) were compared with rapid testing alone, a clinical prediction rule (ie, the modified Centor score), and a criterion standard of treatment for positive throat culture results only. MAIN OUTCOME MEASURES: Sensitivity and specificity of each strategy for identifying GAS pharyngitis, total antibiotics recommended, and unnecessary antibiotic prescriptions. RESULTS: In children, sensitivity for streptococcal infection ranged from 85.8% (133/155; 95% confidence interval [CI], 79.3%-90.0%) for rapid testing to 100% for culturing all. In adults, sensitivity ranged from 76.7% (56/73; 95% CI, 65.4%-85.8%) for rapid testing without culture confirmation of negative results to 100% for culturing all. In children, specificity ranged from 90.3% (270/299; 95% CI, 86.4%-93.4%) for use of modified Centor score and throat culture to 100% for culturing all. In adults, specificity ranged from 43.8% (114/260; 95% CI, 37.7%-50.1%) for empirical treatment based on a modified Centor score of 3 or 4 to 100% for culturing all. Total antibiotic prescriptions were lowest with rapid testing (24.7% [194/787]; 95% CI, 21.7%-27.8%) and highest with empirical treatment of high-risk adults (45.7% [360/787]; 95% CI, 42.2%-49.3%), due to a high rate of unnecessary prescriptions in adults (43.8% [146/333]; 95% CI, 38.4%-49.4%). CONCLUSIONS: Guideline recommendations for the selective use of throat cultures but antibiotic treatment based only on positive rapid test or throat culture results can reduce unnecessary use of antibiotics for treatment of pharyngitis. However, empirical treatment of adults having a Centor score of 3 or 4 is associated with a high rate of unnecessary antibiotic use. In children, strategies incorporating throat culture or throat culture confirmation of negative rapid antigen test results are highly sensitive and specific. Throat culture of all adults or those selected on the basis of a clinical prediction rule had the highest sensitivity and specificity.

Adolescent↗

Tympanocentesis for the management of acute otitis media in children: a survey of Canadian pediatricians and family physicians.

OBJECTIVE: To evaluate the current knowledge, practice patterns, skills, and attitudes of Canadian pediatricians and family physicians regarding the role of diagnostic tympanocentesis in the management of acute otitis media in children. DESIGN: Survey. SETTING AND PARTICIPANTS: A self-completion questionnaire was mailed to a random selection of 302 pediatricians and 196 family physicians practicing in hospitals and community settings across Canada in 2002. A second questionnaire was sent to those who did not respond to the first mailing. MAIN OUTCOME MEASURES: The demographic features of respondents and their attitudes, beliefs, and behaviors regarding tympanocentesis for acute otitis media were collected via a 2-page questionnaire consisting of open-ended and multiple-choice questions. RESULTS: The overall response rate was 56%. Only 4% of pediatricians and family physicians surveyed received training in tympanocentesis, and none currently perform the procedure. Higher proportions of those who learned to perform tympanocentesis graduated from medical school before 1970 and received postgraduate training outside of Canada compared with those who did not learn to perform tympanocentesis. Pediatricians were more likely than family physicians to make referrals to otolaryngologists for tympanocentesis for acute otitis media (62% vs 48%; P = .04). CONCLUSIONS: Few Canadian pediatricians and family physicians in our survey learned to perform tympanocentesis, and none currently perform the procedure. It is not clear whether current practices for tympanocentesis in children with acute otitis media are adequate.

Acute Disease↗

A pharmacoeconomic evaluation of 7-valent pneumococcal conjugate vaccine in Canada.

The objective of this study was to evaluate the projected health benefits, costs, and cost-effectiveness of pneumococcal conjugate vaccination for infants and children aged <5 years in Canada. A health state model incorporating incidence, vaccine efficacy, costs, and transitional probabilities for the health states (well, meningitis, bacteremia, otitis media, pneumonia, and death) was constructed for a 10-year time horizon. Implementation of a pneumococcal conjugate vaccine program in Canada for each annual birth cohort of 340,000 persons observed over 10 years would be expected to save approximately 12 lives and 100,000 cases of pneumococcal disease over 10 years, resulting in total savings of $67 million (Canadian dollars [Can$]). Vaccination of healthy infants would result in net savings for society if the vaccine costs less than Can$50 per dose. Moreover, for a vaccine purchase price of Can$67.50, infant vaccination would cost society Can$79,000 per life-year gained. Pneumococcal conjugate vaccination is a potentially cost-effective means of pneumococcal disease prevention.

Canada↗

Microbiologic findings and risk factors for antimicrobial resistance at myringotomy for tympanostomy tube placement--a prospective study of 601 children in Toronto.

CONTEXT: There is limited information on the identity and antibiotic susceptibility of bacterial pathogens in children with chronic otitis media whose repeated antibiotic use may place them at increased risk of antibiotic-resistant bacteria. OBJECTIVE: To determine, at myringotomy for tympanostomy tube placement, (1) the prevalence of bacteria, (2) the extent and patterns of antibiotic resistance, and (3) the risk factors associated with the presence and resistant status of pathogens. DESIGN: Prospective, multi-site, cohort study. SETTING AND PATIENTS: Children undergoing myringotomy for tympanostomy tube placement between November 1, 1999 and March 31, 2000 in seven hospitals in Toronto, Ontario, were identified. If fluid was present, aspirates were submitted for bacteriologic testing. A follow-up telephone questionnaire was administered to patient caregivers in order to identify risk factors for the presence of (1) culturable pathogens and (2) resistant pathogens. MAIN OUTCOME MEASURES: The identification and prevalence of bacteria cultured from the middle ears of subjects, and the degree of nonsusceptibility to commonly prescribed antibiotics. RESULTS: Among 601 patients (mean age 3.9 years, 60.7% male), both a telephone interview (n=544) and an ear specimen (n=527) were obtained for 478. Pathogens were found in middle ear effusions of 37% of the children in the study; including at least one 'definite' pathogen in 189 children (31.4%), and a further 32 children (5.3%) with at least one 'possible' pathogen. Definite pathogens included Haemophilus influenzae in 17% of the children, followed by Moraxella catarrhalis (9%) and Streptococcus pneumoniae (6%); ampicillin nonsusceptibility was found in 40, 100 and 24%, respectively. Overall, 123 children (20.5%) were found to have definite pathogens with resistance to ampicillin/penicillin, trimethoprim-sulfamethoxazole, or clarithromycin/erythromycin. Patient characteristics included premature birth and/or long length of stay in the nursery (23%), first infection before the age of 6 months (26%), put to bed with a bottle (28%), household smoker (34%), in out-of-home child care (38%), history of eczema, bronchiolitis and/or asthma (39%), and use of pacifiers (40%). Household characteristics were smoking (34%), married/common law parents (85%), and 60% had completed college or university; in 26% both parents were born outside of Canada; 73% of children were Caucasian. Of the 75% who responded to the question regarding income, 42% had household income over $60,000 (CAN). Risk factors for the presence of a pathogen and for a resistant pathogen in multivariate analysis included younger age, lower maternal education, day care centre attendance, no previous adenoidectomy and bilateral, primarily winter infections as well as amoxicillin use in the previous 6 months. CONCLUSION: Modifiable risk factors for otitis media including household smoking and pacifier use are present in many children undergoing tympanostomy tube placement; child care centre attendees are over-represented. Multiple antibiotic courses were commonly prescribed prior to surgery. H. influenzae and M. catarrhalis are important pathogens and therapy in clinical failures should be directed against them. The 7-valent protein conjugate polysaccharide vaccine (Prevnar) would have covered 73% of the serotypes of S. pneumoniae isolated in this study.

Adolescent↗

Population-based, age-specific myringotomy with tympanostomy tube insertion rates in Calgary, Canada.

Population-based rates of myringotomy with tympanostomy tube insertions in Calgary from 1997 to 2000 were determined with the use of administrative databases. Age-specific rates (procedures per 1,000 people per year) were 12.8, 54.2 and 11.1 for ages 0 to 11 months, 12 to 23 months and 0 to 15 years, respectively. Repeated procedures were performed on 7.1% of children <5 years of age.

Adolescent↗

Outcome of penicillin-nonsusceptible Streptococcus pneumoniae meningitis: a nested case-control study.

BACKGROUND: There are few data comparing the clinical features, management and outcome of penicillin-nonsusceptible (PNSP) meningitis patients with penicillin-susceptible (PSSP) meningitis patients. METHODS: We performed a retrospective, nested case-control study comparing cases with PNSP meningitis with controls with PSSP meningitis obtained from the Immunization Monitoring Program, Active (IMPACT) cross-Canada surveillance study of invasive infections. RESULTS: There were 30 PNSP meningitis cases (10.1% of total) and 45 PSSP meningitis controls from 6 centers obtained from 297 meningitis cases in the IMPACT database from 1991 through 1999. Vancomycin was used for empiric therapy in no cases and controls in 1991 to 1993 and in all cases in 1999. A third generation cephalosporin was used in 93.3% of confirmed PNSP cases, and 70.0% also received vancomycin and/or rifampin. Penicillin was used in 66.7% of confirmed PSSP cases. PNSP cases were more likely than PSSP controls to have a second lumbar puncture (odds ratio, 4.1; P= 0.01). PNSP cases were treated with intravenous antibiotics for an average of 15.6 days compared with 12.3 days for controls ( P= 0.04). Among PNSP cases, those patients who did not receive empiric vancomycin were treated with intravenous antibiotics for an average of 18.5 days compared with 12.0 days for those who did receive empiric vancomycin ( P= 0.04). The overall mortality was 5.3%, and 36.6% of survivors had >or=1 neurologic sequelae, including 19.7% with hearing loss. In multivariate statistical models, PNSP was not a risk factor for intensive care unit admission or neurologic sequelae. CONCLUSIONS: Management of suspected bacterial meningitis and confirmed meningitis in Canadian children changed in the past decade. Treatment of PNSP meningitis is significantly different from that for PSSP meningitis. These changes have occurred in response to the emergence of PNSP in Canada. Neurologic sequelae remain common after meningitis, but there are no differences between PNSP cases and PSSP cases.

Adolescent↗

Rotavirus gastroenteritis.

Rotavirus is the single most important cause of severe, dehydrating gastroenteritis in infants and young children worldwide. Rotavirus gastroenteritis is associated with high morbidity in developed countries and significant mortality in developing countries. Virtually all children are infected with rotavirus by 3 years of age. Fecal-oral transmission is the most likely route of virus spread. Group A serotype strains G1 through G4 account for more than 90% of rotavirus gastroenteritis in humans, with G1 being the predominant serotype. The virus preferentially infects the mature small-intestinal enterocytes. Rotavirus gastroenteritis is characterized by fever, vomiting, and diarrhea, with vomiting particularly prominent. Dehydration is a frequent complication because of the severity of the diarrhea and the associated vomiting. Rehydration and maintenance of proper fluid and electrolyte balance remain the mainstay of treatment. Hygienic measures have little effect on the reduction of rotavirus infection rates. The disease can be effectively controlled by universal rotavirus vaccination.

Child, Preschool↗

Genital infection with human papillomavirus in adolescents.

Human papillomavirus (HPV) infection is one of the most common sexually transmitted infections in adolescents. Such infection is associated with substantial health risks and is unpredictable in its resolution. Genital warts are the most common clinical manifestations of genital HPV infections. Most genital warts are caused by low risk HPV types (notably HPV-6 and -11). The majority of genital HPV infections are latent or subclinical. Although the outcome of a genital HPV infection is variable, the infection is usually transient and complete resolution is common. However, persistent infections with high-risk HPV types (notably HPV-16 and -18) are associated with the development of cervical intraepithelial dysplasia (CIN), which may progress to cervical cancer. Genital warts, generally diagnosed in the clinic, can be treated with imiquimod, podofilox, podophyllin, liquid nitrogen, bichloroacetic or trichloroacetic acid, or surgery. Cervical cytology screening is an ideal screening test for subclinical HPV infection with resultant CIN. Annual cervical cytology screening should begin approximately 3 years after initiation of sexual intercourse but no later than age 21 years. Because of the high rate of regression of low-grade squamous intraepithelial lesions (LSIL) in adolescents, the cytologic study should be repeated within 6 to 12 months. Colposcopy should be reserved for persistent LSIL. Patients with high-grade squamous intraepithelial lesions (HSIL) should be referred for colposcopy and biopsy. Confirmed HSIL should be treated with cryotherapy, laser therapy, or loop electrosurgical excisional procedure. The use of therapeutic vaccines is still experimental. HPV infection can be prevented, to a certain extent, by delaying the initiation of sexual activity, limiting the number of sexual partners, and using latex condoms. Several viruslike particle candidate vaccines are under development for the prevention of HPV. These vaccines have been proven safe, well tolerated, highly immunogenic, and highly efficacious. Such vaccines are urgently needed and ultimately may be an important preventive measure.

Adolescent↗

Hepatitis A: a preventable threat.

Hepatitis A is a major public health problem, particularly in the pediatric population. Although hepatitis A infection does not cause chronic liver disease, it is associated with significant morbidity. The virus is transmitted primarily by person-to-person contact via the fecal-oral route. The infection can be inapparent, subclinical, anicteric, or icteric. In general, the severity of the disease is inversely correlated with the age of the child. Occasionally, fulminant hepatitis, which is associated with a high mortality rate, may result. The diagnosis of acute hepatitis A is most commonly made through the detection of immunoglobulin M (IgM) anti-hepatitis A antibody. Treatment is generally supportive. General preventive measures include improved standards of hygiene and sanitation. Universal childhood vaccination is the most effective method for eradicating hepatitis A and preventing its transmission.

Diagnosis, Differential↗

Group A beta-hemolytic streptococcal pharyngitis in children.

Group A beta-hemolytic streptococcus (GABHS) is the most common bacterial cause of acute pharyngitis in children. Because clinical findings can be nonspecific, even experienced physicians cannot reliably diagnose GABHS pharyngitis solely on the basis of clinical presentation. Suspected cases should be confirmed by a throat culture or a rapid antigen detection test before antibiotic therapy is initiated. Microbiologic testing is generally not necessary in patients with pharyngitis whose clinical and epidemiologic findings are not suggestive of GABHS. Clinical score systems have been developed to help physicians decide which patients should undergo diagnostic testing and to reduce the unnecessary use of antibiotics. Antibiotic therapy should be initiated as soon as the diagnosis is confirmed. Penicillin V remains the drug of choice. Alternative therapy, e.g., with cephalosporin or macrolide, is often sought because of penicillin allergy, noncompliance, and treatment failure.

Acute Disease↗

Acute sinusitis in children: diagnosis and management.

Acute sinusitis is a common problem in children that is often overlooked. The pathophysiology is related to obstruction of the sinus ostia and mucociliary dysfunction. The predominant pathogens include Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. The diagnosis of acute sinusitis is based on persistent or severe upper respiratory tract symptoms. The routine use of roentgenograms to confirm the diagnosis of uncomplicated sinusitis is not recommended for children 6 years or younger but may be considered for children older than 6 years. Antimicrobial therapy is the cornerstone of management and amoxicillin is the drug of choice for most cases of uncomplicated sinusitis.

Acute Disease↗

Viral croup: a current perspective.

Viral croup is the most common cause of upper airway obstruction in children 6 months to 6 years of age. Parainfluenza virus accounts for the majority of cases. The disease is characterized by varying degrees of inspiratory stridor, barking cough, and hoarseness because of laryngeal and/or tracheal obstruction. The diagnosis is mainly a clinical one and diagnostic studies usually are not necessary. The management has altered dramatically in the past decade. Good evidence exists to support the routine use of corticosteroid in all children with croup. Intervention at an earlier phase of the illness will reduce the severity of the symptoms and the rates of return to a health care practitioner for additional medical attention, visits to the emergency department, and admission to the hospital. Most children respond to a single, oral dose of dexamethasone. For those who do not tolerate the oral preparation, nebulized budesonide or intramuscular dexamethasone are reasonable alternatives. Nebulized epinephrine should be reserved for patients with moderate to severe croup. Simultaneous administration of corticosteroid and epinephrine reduces the rate of intubation in patients with severe croup and impending respiratory failure.

Administration, Inhalation↗