Robert R. Tanz

Dexamethasone in bronchiolitis: a randomised controlled trial

BACKGROUND Although corticosteroids are commonly prescribed in the treatment of bronchiolitis, there is no evidence on the efficacy of these drugs in this disorder. We designed a randomised, double-blind, prospective study to assess the efficacy of dexamethasone in infants with bronchiolitis who require hospital management. METHODS Infants younger than 12 months who had been admitted to hospital for an initial episode of wheezing, were randomly allocated intramuscular dexamethasone (1 mg/kg daily) or placebo, every 24 h for three doses. We excluded infants who were younger than 4 weeks, who required admission to the intensive care unit, or who had a history of congenital heart disease, mechanical ventilation, or supplemental oxygen use. We assessed infants on admission and every 12 h thereafter--vital signs were taken, severity of accessory muscle use and wheezing were measured by a clinical severity score, and pulse oximetry in room air was done. Our primary endpoints were the time to resolution of symptoms--defined as the number of assessments needed to reach oxygen saturation of more than 95% while receiving no supplemental oxygen, an accessory muscle score of 0, a wheeze score of 0 or 1, and resumption of normal feeding--and duration of oxygen therapy. Follow-up assessments were made 10-14 days after discharge by telephone. We used a proportional-hazards model for our survival analysis. FINDINGS 197 infants presented with bronchiolitis that required inpatient management. 75 were not enrolled (31 no consent, 28 no approach made, 16 transferred elsewhere). Of the 122 enrolled, four were excluded (clinical deterioration, diagnosis of cystic fibrosis, previous intubation, did not receive all study treatment). There were no differences between the dexamethasone (n = 65) and placebo-treated infants in demographic factors, exposure to tobacco smoke, duration of illness, presence of respiratory syncytial virus (RSV) antigen, respiratory rate, or severity score. More dexamethasone-treated patients had an initial oxygen saturation of 95% or less (51 [79%] dexamethasone vs 31 [59%] placebo, p = 0.02). There were no differences in duration of oxygen therapy (p = 0.74) or time to resolution of symptoms (p = 0.22). Stratification for presence of RSV antigen or family history of atopy did not affect the results. INTERPRETATION Our findings do not support the use of dexamethasone in the treatment of bronchiolitis in infants.

Antibiotic administration to treat possible occult bacteremia in febrile children.

We performed a prospective, randomized, placebo-controlled, double-blind clinical trial of antibiotic administration to treat possible occult bacteremia in febrile children. A total of 955 children aged 3 to 36 months with temperatures greater than or equal to 39.0 degrees C and no focal bacterial infection were enrolled at the emergency departments of two childrens hospitals from January 1982 until July 1984. Blood samples for culture were obtained, and the children were randomly assigned to receive either oral amoxicillin or placebo and were restudied approximately 48 hours after enrollment. Data were also collected on 228 children who could not be randomly assigned. Twenty-seven of the randomly assigned children (2.8 percent) had bacteremic infections with pathogenic organisms (Streptococcus pneumoniae, Haemophilus influenzae, and salmonella). There were no differences in the incidence of major infectious morbidity associated with bacteremia between the antibiotic and placebo groups--2 of 19 patients (10.5 percent) in the antibiotic group and 1 of 8 (12.5 percent) in the placebo group--although the power for this comparison was low. Antibiotics reduced fever (P less than 0.005) and improved the clinical appearance (P = 0.07) in the children with bacteremia but not in those without bacteremia. Although there were no statistically significant differences in the incidence of side effects, diarrhea tended to occur more often in the patients treated with amoxicillin (15 vs. 11 percent, P less than 0.10). We conclude that our data do not support the routine use of standard oral doses of amoxicillin in febrile children who do not have evidence of focal bacterial disease.

Temporal Changes in Streptococcal M Protein Types and the Near-Disappearance of Acute Rheumatic Fever in the United States

BACKGROUND The explanation for the very substantial decrease in the incidence of acute rheumatic fever in the United States, particularly over the past 50 years, is unclear. It has been proposed that certain M types of group A streptococci (GAS) include strains that are particularly rheumatogenic and that others are nonrheumatogenic. METHODS We compared the M type distribution of GAS recovered from children from Chicago, Illinois, with acute pharyngitis during 1961-1968 to that of GAS recovered from Chicago children and children from across the United States in 2000-2004, with attention to changes in M types that previously were associated with rheumatogenic strains. RESULTS The rheumatogenic types 3, 5, 6, 14, 18, 19, and 29 comprised 49.7% of 468 pharyngeal isolates during 1961-1968 but only 10.6% of 450 Chicago isolates during 2000-2004 (P < .001) and 17.9% of 3969 isolates nationwide during 2000-2004 (P < .001). Significant decreases in types 3, 5, and 6 and virtual disappearance of types 14, 18, 19, and 29 occurred between the 2 study periods. No change in the proportion of type 1 isolates, a highly heterogeneous group that includes some rheumatogenic strains, was observed. The nonrheumatogenic GAS types 2, 4, 22, and 28 increased from 4.9% to approximately 28% of pharyngeal isolates in Chicago and nationwide between the 2 study periods (P < .001). CONCLUSIONS These data support the concept of rheumatogenic strains of GAS and indicate that the marked decrease in the incidence of acute rheumatic fever in the United States over the past 4 decades is correlated with the replacement of rheumatogenic types by nonrheumatogenic types in cases of acute streptococcal pharyngitis in children. The reasons underlying the observed change in distribution of M types remain to be elucidated.

Penicillin plus rifampin eradicates pharyngeal carriage of group A streptococci

We evaluated the efficacy of rifampin in eradicating chronic pharyngeal carriage of group A streptococci. Carriers were defined as healthy children whose throat cultures showed persistence of group A streptococci 3 weeks after receiving benzathine penicillin G intramuscularly. Subsequent M and T typing of group A streptococcal isolates and limited serologic studies confirmed that enrolled patients were carriers. Thirty-eight carriers (37 completed the study) were randomly assigned to three groups: group 1 (13 patients) received no treatment; group 2 (10) received benzathine penicillin intramuscularly; group 3 (14) received benzathine penicillin intramuscularly plus rifampin orally (10 mg/kg twice a day for eight doses). Throat cultures were obtained every 3 weeks for at least 9 weeks. Group 2 and 3 patients who still had positive cultures 3 weeks after treatment were crossed to the opposite group. Cultures became negative in 93% (13 of 14) of patients in group 3, compared with 23% in group 1 and 30% in group 2 (P less than 0.001 and P less than 0.01, respectively). Including patients crossed over, the penicillin plus rifampin regimen was effective in 17 (89%) of 19 treatment courses and was significantly superior to no therapy or to penicillin alone (P less than 0.0005 and P less than 0.005, respectively). We conclude that rifampin plus benzathine penicillin intramuscularly is an effective regimen for those selected patients in whom eradication of group A streptococcal carriage is judged to be desirable.

Seven-Year Surveillance of North American Pediatric Group A Streptococcal Pharyngitis Isolates

BACKGROUND Pharyngeal group A streptococcal (GAS) emm type surveillance enhances understanding of the epidemiology of pharyngitis and invasive GAS disease and formulation of multivalent type-specific vaccines. In addition, such surveillance provides pre-GAS vaccine baseline data. We assessed geographic and temporal trends in GAS emm-type distribution among pediatric pharyngeal isolates collected systematically in the United States and Canada from 2000 to 2007. METHODS We collected approximately 100 acute GAS pharyngitis isolates from each of 13 widely scattered sites (10 in the United States and 3 in Canada) annually for 7 seasons (2000-2007) from 3- to 18-year-old children. We assessed emm type and subtype by DNA sequencing and analyzed temporal and geographic trends. RESULTS A total of 7040 US and 1434 Canadian GAS isolates were studied. The 6 most prevalent emm types (in descending order) were 1, 12, 28, 4, 3, and 2 in the United States and 12, 1, 28, 4, 3, 2, and 77 in Canada, constituting 70%-71% of isolates in each country; 10 emm types constituted 87%-89% total. Fifty-six emm types were identified in the United States, including 8 new types, and 33 types in Canada. Although a few types predominated nationally, marked variability among individual sites and at individual sites from year to year was observed. US-Canadian differences in type distribution were apparent. Twenty percent of isolates represented emm subtypes that differed slightly from reference types; 110 new subtypes were identified. An experimental 26-valent M protein vaccine covers 85% of pharyngitis isolates. CONCLUSIONS Although overall US and Canadian emm type distribution was consistent and relatively few types dominated nationally, striking intersite and temporal variations within individual sites in prevalent emm types of GAS occurred. These results have important implications for the development and formulation of type-specific GAS vaccines.

Performance of a rapid antigen-detection test and throat culture in community pediatric offices: Implications for management of pharyngitis

OBJECTIVES. The goals were to establish performance characteristics of a rapid antigen-detection test and blood agar plate culture performed and interpreted in community pediatric offices and to assess the effect of the pretest likelihood of group A streptococcus pharyngitis on test performance (spectrum bias). METHODS. Two throat swabs were collected from 1848 children 3 to 18 years of age who were evaluated for acute pharyngitis between November 15, 2004, and May 15, 2005, in 6 community pediatric offices. One swab was used to perform the rapid antigen-detection test and a blood agar plate culture in the office and the other was sent to our laboratory for blood agar plate culture. Clinical findings were used to calculate the McIsaac score for each patient. The sensitivities of the office tests were calculated, with the hospital laboratory culture results as the criterion standard. RESULTS. Thirty percent of laboratory blood agar plate cultures yielded group A streptococcus (range among sites: 21%–36%). Rapid antigen-detection test sensitivity was 70% (range: 61%–80%). Office culture sensitivity was significantly greater, 81% (range: 71%–91%). Rapid antigen-detection test specificity was 98% (range: 98%–99.5%), and office culture specificity was 97% (range: 94%–99%), a difference that was not statistically significant. The sensitivity of a combined approach using the rapid antigen-detection test and back-up office culture was 85%. Among patients with McIsaac scores of >2, rapid antigen-detection test sensitivity was 78%, office culture sensitivity was 87%, and combined approach sensitivity was 91%. Positive diagnostic test results were significantly associated with McIsaac scores of >2. CONCLUSIONS. The sensitivity of the office culture was significantly greater than the sensitivity of the rapid antigen-detection test, but neither test was highly sensitive. The sensitivities of each diagnostic modality and the recommended combined approach were best among patients with greater pretest likelihood of group A streptococcus pharyngitis.

Clindamycin treatment of chronic pharyngeal carriage of group A streptococci

We previously demonstrated that chronic pharyngeal carriage of group A beta-hemolytic streptococci (GABHS) can be terminated by intramuscular administration of benzathine penicillin plus 4 days of orally administered rifampin. Because an effective oral regimen would be desirable, we compared clindamycin with P + R for treating GABHS carriage. Healthy, symptom-free GABHS carriers were randomly assigned to receive orally administered clindamycin (20 mg/kg per day) three times a day for 10 days or intramuscularly administered benzathine penicillin with oral doses of rifampin (20 mg/kg per day) twice a day for 4 days. Compliance was documented by antibiotic activity in urine. Throat cultures for GABHS were obtained every 3 weeks for up to 9 weeks after treatment. Patients who had positive throat cultures for their original GABHS T type 3 weeks after randomization were crossed over to the other treatment. Treatment success was defined as eradication of the original GABHS T type, with all follow-up cultures negative. Clindamycin eradicated carriage in 24 (92%) of 26 patients; penicillin plus rifampin was effective in 12 (55%) of 22 patients (p less than 0.025). Including patients crossed over 3 weeks after enrollment, clindamycin was effective in 28 (85%) of 33 treatment courses compared with 12 of 22 courses of penicillin plus rifampin (p less than 0.05). We conclude that 10 days of oral clindamycin therapy was significantly more effective than benzathine penicillin plus 4 days of orally administered rifampin for treatment of symptom-free GABHS carriers.

The role of bone scintigraphy in detecting child abuse

This review of diagnostic imaging in cases of suspected child abuse characterizes the significant differences between bone scintigraphy and x-ray evaluation, describes the advantages and disadvantages of each modality, postulates on the specific mechanisms of injury that produce the characteristic scintigraphic findings, and emphasizes the influences that scintigraphic studies have on the medical, social, and legal aspects of child abuse. The major advantages of bone scintigraphy are its increased sensitivity (25% to 50%) in detecting evidence of soft tissue as well as bone trauma in child abuse. Furthermore, it is postulated that the specific mechanisms of inflicting the trauma relate to the patients size and are characterized by bone scintigraphy. During fits of anger or frustration, the perpetrator of child abuse grasps the small infant or child by the thorax during the shaking activity. This produces characteristic rib injuries. The older and heavier child is more likely to be grabbed by the extremities, which produces periosteal injuries manifested as characteristic abnormal localizations in the diaphyses of the extremities. The roentgenograms of these injuries are frequently normal. The importance of bone scintigraphy is its complementary nature in defining and characterizing the extent and severity of trauma from child abuse. Such findings have direct bearing on the medical, social, and legal outcomes for the abused child. The quality of scintigraphic imaging is important, requiring the use of magnification techniques in the infant. The interpretation of the scintigraphic images depends on an understanding of the mechanisms by which the radionuclide localizes in bone. The same traumatic incident can lead to decreased, normal, or increased localization at the trauma site. Radionuclide scintigraphy is a complementary rather than competitive imaging modality to X-ray evaluation in the diagnosis and management of physical child abuse.

Potential Mechanisms for Failure to Eradicate Group A Streptococci From the Pharynx

Objective. To investigate the relative efficacy of orally administered cefadroxil and penicillin V in the treatment of group A streptococcal (GABHS) pharyngitis and the mechanism(s) responsible for failure of antimicrobial therapy to eradicate GABHS from the pharynx. Study Design. A prospective, randomized clinical trial was conducted in four pediatric offices in which 462 patients with acute pharyngitis and positive culture for GABHS were randomly assigned to receive cefadroxil (n = 232) or penicillin V (n = 230). Results. Bacteriologic treatment success rates for patients in cefadroxil and penicillin groups were 94% and 86%, respectively. However, among patients classified clinically as likely to have bona fide GABHS pharyngitis, there was no difference in bacteriologic treatment success rates in cefadroxil and penicillin groups (95% and 94%, respectively). Among patients classified clinically as likely to be streptococcal carriers, bacteriologic treatment success rates in cefadroxil and penicillin groups were 92% and 73%, respectively. The presence of β-lactamase and/or bacteriocin-producing pharyngeal flora had no consistent effect on bacteriologic eradication rates among patients in either penicillin or cefadroxil treatment groups or among patients classified as having either GABHS pharyngitis or streptococcal carriage. Conclusions. Neither β-lactamase nor bacteriocin produced by normal pharyngeal flora are related to bacteriologic treatment failures in GABHS pharyngitis. Cefadroxil seems to be more effective than penicillin V in eradicating GABHS from patients classified as more likely to be streptococcal carriers. However, among patients we classified as more likely to have bona fide GABHS pharyngitis, the effectiveness of cefadroxil and penicillin V seems to be comparable.

Community-Based Surveillance in the United States of Macrolide-Resistant Pediatric Pharyngeal Group A Streptococci during 3 Respiratory Disease Seasons

BACKGROUND In 2001, a total of 48% of pharyngeal group A streptococci (GAS) from Pittsburgh children were macrolide resistant. We assessed macrolide resistance, resistance genes, and emm types among GAS in the United States. METHODS In prospective, multicenter, community-based surveillance of pharyngeal GAS recovered from children 3-18 years old during 3 respiratory seasons (the 2000-2001 season, the 2001-2002 season, and the 2002-2003 season), GAS were tested for macrolide resistance and underwent emm gene sequencing. Macrolide-resistant GAS were tested for resistance to clindamycin, and resistance genes were determined. RESULTS Erythromycin resistance was observed in 4.4% of isolates from the 2000-2001 season, 4.3% from the 2001-2002 season, and 3.8% from the 2002-2003 season (P=.80). Clindamycin resistance was found in 1.04% of isolates; annual rates of clindamycin resistance were stable (P=.75). The predominant resistance genotype each year was mef A (65%-76.9%; overall, 70.3%). Resistant isolates included strains representing 8-11 different emm types each year. Heterogeneity of emm subtypes, resistance genes, and clindamycin resistance was evident among resistant isolates within some emm types. Geographic variability in resistance rates was present each year. CONCLUSIONS The macrolide resistance rate among pharyngeal GAS was <5% and was stable over the 3 seasons. However, rates varied among sites each year. There was no evidence of spread of a specific resistant clone, increasing clindamycin resistance, or escalation in median erythromycin MICs.