Biomedical subjects
Publications and source records attributed to Ari Bitnun.
The presentation of HIV in children varies between developed and developing countries. In addition, the presentation in adolescents may differ from that in younger children. This report highlights a rare presentation and complication of HIV in children and emphasizes the importance of cultural competency when approaching children and families from different cultural backgrounds.
Many neurologic manifestations of Epstein-Barr virus (EBV) infection have been documented, including encephalitis, aseptic meningitis, transverse myelitis, and Guillain-Barré syndrome. These manifestations can occur alone or coincidentally with the clinical picture of infectious mononucleosis. Since 1994, The Hospital for Sick Children has maintained a prospective registry of all children admitted with acute encephalitis. This report summarizes all cases of Epstein-Barr virus-associated encephalitis compiled from 1994 to 2003. Twenty-one (6%) of 216 children, median age 13 years (range 3-17 years), in the Encephalitis Registry were identified as having evidence of Epstein-Barr virus infection. This evidence consisted of convincing Epstein-Barr virus serology and/or positive cerebrospinal fluid polymerase chain reaction (PCR). One patient had symptoms of classic infectious mononucleosis; all others had a nonspecific prodrome, including fever (n = 17; 81%) and headache (n = 14; 66%). Slightly less than half (n = 10; 48%) had seizures and often had electroencephalograms showing a slow background (n = 12; 57%). Many demonstrated cerebrospinal fluid pleocytosis (n = 17; 81%), and 71% (n = 15) had abnormal magnetic resonance imaging findings. Two patients died, 2 suffered mild deficits, and 16 were neurologically normal at follow-up. Most patients with Epstein-Barr virus encephalitis do not show typical symptoms of infectious mononucleosis. Establishing a diagnosis of Epstein-Barr virus encephalitis can be difficult, and, consequently, a combination of serologic and molecular techniques should be used when investigating a child with acute encephalitis. Most children make full recoveries, but residual neurologic sequelae and even death can and do occur.
Previous pediatric studies have failed to demonstrate a clear association between protease inhibitor (PI) therapy and abnormal glucose homeostasis in HIV-infected children. To define more precisely the impact of PI therapy on glucose homeostasis in this population, we performed the insulin-modified frequent-sampling iv glucose tolerance test on 33 PI-treated and 15 PI-naive HIV-infected children. Other investigations included fasting serum lipids; glucose, insulin, and C-peptide; single-slice abdominal computed tomography; and, in a subset of PI-treated children, an oral glucose tolerance test. There were no differences between the two groups with respect to fasting serum insulin or C-peptide, homeostatic model assessment insulin resistance, or quantitative insulin sensitivity check index. The mean insulin sensitivity index of PI-treated and PI-naive children was 6.93 +/- 6.37 and 10.58 +/- 12.93 x 10(-4)min(-1) [microU/ml](-1), respectively (P = 0.17). The mean disposition index for the two groups was 1840 +/- 1575 and 3708 +/- 3005 x 10(-4)min(-1) (P = 0.013), respectively. After adjusting for potential confounding variables using multiple regression analysis, the insulin sensitivity index and disposition index of PI-treated children were significantly lower than that of PI-naive children (P = 0.01 for both). In PI-treated but not PI-naive children, insulin sensitivity correlated inversely with visceral adipose tissue area (r = -0.43, P = 0.01) and visceral to sc adipose tissue ratio (r = -0.49, P = 0.004). Mildly impaired glucose tolerance was noted in four of 21 PI-treated subjects tested. Our results demonstrate not only that PI therapy reduces insulin sensitivity in HIV-infected children but also that it impairs the beta-cell response to this reduction in insulin sensitivity and, in a subset of children, leads to the development of impaired glucose tolerance. The presence of insulin resistance, dyslipidemia, and the significant correlation of reduced insulin sensitivity with increased visceral adipose tissue content suggest that PI-containing highly active antiretroviral therapy is associated with the emergence of early features of a metabolic syndrome-like phenotype.
BACKGROUND: Severe acute respiratory syndrome (SARS) is a recently recognized condition of viral origin associated with substantial morbidity and mortality rates in adults. Little information is available on its radiologic manifestations in children. OBJECTIVE: The goal of this study was to characterize the radiographic presentation of children with SARS. MATERIALS AND METHODS: We abstracted data (n=62) on the radiologic appearance and course of SARS in pediatric patients with suspect (n=25) or probable (n=37) SARS, diagnosed in five hospital sites located in three cities: Toronto, Singapore, and Hong Kong. Available chest radiographs and thoracic CTs were reviewed for the presence of the following radiographic findings: airspace disease, air bronchograms, airways inflammation and peribronchial thickening, interstitial disease, pleural effusion, and hilar adenopathy. RESULTS: A total of 62 patients (suspect=25, probable=37) were evaluated for SARS. Patient ages ranged from 5.5 months to 17 years and 11.5 months (average, 6 years and 10 months) with a female-to-male ratio of 32:30. Forty-one patients (66.1%) were in close contact with other probable, suspect, or quarantined cases; 10 patients (16.1%) had recently traveled to WHO-designated affected areas within 10 days; and 7 patients (11.2%) were transferred from other hospitals that had SARS patients. Three patients, who did not have close/hospital contact or travel history to affected areas, were classified as SARS cases based on their clinical signs and symptoms and on the fact that they were living in an endemic area. The most prominent clinical presentations were fever, with a temperature over 38 degrees C (100%), cough (62.9%), rhinorrhea (22.6%), myalgia (17.7%), chills (14.5%), and headache (11.3%). Other findings included sore throat (9.7%), gastrointestinal symptoms (9.7%), rigor (8.1%), and lethargy (6.5%). In general, fever and cough were the most common clinical presentations amongst younger pediatric SARS cases (age<10 years), whereas, in addition to these symptoms, headache, myalgia, sore throat, chills, and/or rigor were common in older patients (age>/=10 years). The chest radiographs of 35.5% of patients were normal. The most prominent radiological findings that were observed in the remaining patients were areas of consolidation (45.2%), often peripheral with multifocal lesions in 22.6%. Peribronchial thickening was noted on chest radiographs of 14.5% of patients. Pleural effusion was observed only in one patient (age 17 years and 11.5 months), whereas interstitial disease was not observed in any patient. CONCLUSION: In pediatric cases, SARS manifests with nonspecific radiographic features making radiological differentiation difficult, especially from other commonly encountered childhood respiratory viral illnesses causing airspace disease. The radiographic presentation of suspected SARS cases ranged from normal to mild perihilar peribronchial thickening. The radiographic presentations, as expected, were relatively more pronounced in the SARS probable cases.
OBJECTIVE: To determine the extent and degree of abnormalities of serum lipids, glucose homeostasis and abdominal adipose tissue distribution in protease inhibitor (PI)-treated and PI-naive HIV-infected children. DESIGN: A cross-sectional study involving HIV-infected children, 3-18 years of age, in a paediatric tertiary care centre. MAIN OUTCOME MEASURES: Total, HDL and LDL-cholesterol, triglycerides, glucose, insulin, proinsulin and C-peptide were determined in the fasting state. Insulin resistance was assessed using the homeostatic model assessment-insulin resistance (HOMA-IR). Abdominal adipose tissue distribution was determined by single-slice computed tomography at the umbilical level. RESULTS: Thirty PI-treated and 20 PI-naive children were evaluated (76% prepubertal). PI-treated children had significantly higher total cholesterol (P = 0.0021), LDL-cholesterol (P = 0.019) and triglycerides (P = 0.0018). Serum glucose, insulin, proinsulin and C-peptide, the insulin : glucose ratio, HOMA-IR and abdominal adipose tissue distribution were similar in the two groups. Clinical and immunological HIV categories, viral load, CD4 cell count and stavudine therapy were not significantly associated with serum lipids, insulin resistance or abdominal adipose tissue distribution. The predictor variable most strongly associated with fasting serum insulin and HOMA-IR was the Tanner stage. Age was the most significant predictor variable of the visceral : subcutaneous adipose tissue ratio. CONCLUSION: In this cohort of predominantly prepubertal HIV-infected children, PI therapy was associated with an atherogenic dyslipidemia but not with insulin resistance or abnormal abdominal adipose tissue distribution. The results suggest that children, particularly prepubertal children, are less susceptible than adults to PI-induced changes in glucose homeostasis and abdominal adipose tissue distribution.
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Mycoplasma pneumoniae causes between 5 and 10 percent of acute childhood encephalitis in Europe and North America. Encephalitis due to this organism may be caused by direct infection of the brain, immune-mediated brain injury or thromboembolic phenomenon. The prognosis is guarded with 20 to 60 percent suffering neurologic sequelae. The diagnosis of M. pneumoniae encephalitis should be based on strong evidence of M. pneumoniae infection that includes detection of the organism in culture or using molecular detection techniques in addition to serology and exclusion of other potential etiologies. Antibiotic therapy should be considered for all children with suspected M. pneumoniae encephalitis; antibiotics with good central nervous system (CNS) penetration such as ciprofloxacin, doxycycline, chloramphenicol or azithromycin are appropriate under most circumstances. Immune modulating therapies, such as corticosteroids, intravenous immune globulin or plasmapharesis, should be considered in those with immune-mediated syndromes such as acute disseminated encephalomyelitis.
OBJECTIVE: An outbreak of severe acute respiratory syndrome (SARS) occurred in the greater Toronto area between February and June 2003. We describe the clinical, laboratory, and epidemiologic features of children who were admitted to the Hospital for Sick Children, Toronto, with a presumptive diagnosis of suspect or probable SARS. METHODS: A prospective investigational study protocol was established for the management of children with a presumptive diagnosis of suspect or probable SARS. All were ultimately classified as having probable SARS, suspect SARS, or another cause on the basis of their epidemiologic exposure, clinical and radiologic features, and results of microbiologic investigations. RESULTS: Twenty-five children were included; 10 were classified as probable SARS and 5 were classified as suspect SARS, and in 10 another cause was identified. The exposure consisted of direct contact with at least 1 adult probable SARS case in 11 children, travel from a World Health Organization-designated affected area in Asia in 9 children, and presence in a Toronto area hospital in which secondary SARS spread had occurred in 5 children. The predominant clinical manifestations of probable cases were fever, cough, and rhinorrhea. With the exception of 1 teenager, none of the children developed respiratory distress or an oxygen requirement, and all made full recoveries. Mild focal alveolar infiltrates were the predominant chest radiograph abnormality. Lymphopenia; neutropenia; thrombocytopenia; and elevated alanine aminotransferase, aspartate aminotransferase, and creatine kinase were present in some cases. Nasopharyngeal swab specimens were negative for the SARS-associated coronavirus by an in-house reverse transcriptase-polymerase chain reaction in all 25 children. CONCLUSIONS: Our results indicate that SARS is a relatively mild and nonspecific respiratory illness in previously healthy young children. The presence of fever in conjunction with a SARS exposure history should prompt one to consider SARS as a possible diagnosis in children irrespective of the presence or absence of respiratory symptoms. Reverse-transcriptase polymerase chain reaction analysis of nasopharyngeal specimens seems to be of little utility for the diagnosis of SARS during the early symptomatic phase of this illness in young children.
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