Polymerase chain reaction diagnosis of primary human herpesvirus-6 infection in the acute care setting

OBJECTIVE: To evaluate the potential utility of identifying primary human herpesvirus (HHV)-6 infection in an emergency department setting by determining the frequency of HHV-6 viremia, diagnostic testing, and empiric treatment of serious bacterial infection (SBI) in HHV-6 viremic children, and concurrent SBI and HHV-6 viremia. STUDY DESIGN: Children under age 2 years and who had a blood specimen taken for evaluation of fever were tested for HHV-6 by polymerase chain reaction (PCR). HHV-6 viremia was defined as detection of HHV-6 DNA in acute plasma. RESULTS: A total of 32 of the 181 subjects (18%) had HHV-6 viremia. Children with HHV-6 viremia frequently underwent procedures for diagnosis and empiric treatment of SBI: 60% had bladder catheterizations, 6% had lumbar punctures, 47% had radiographs, 32% received empiric antibiotics, and 34% were hospitalized. Four of the 32 children with HHV-6 viremia (12.5%) were diagnosed with SBI, although none had a positive culture of blood or cerebrospinal fluid. CONCLUSIONS: Rapid diagnosis of HHV-6 viremia may not serve to adequately differentiate infants with and without SBI in acute care settings. Although no children with HHV-6 viremia had bacteremia or meningitis, it appears that additional criteria are needed to increase the specificity of HHV-6 PCR testing before withholding evaluation for SBI.     

Miliary TB with pelvic mass and choroidal tubercles in a child: Case report

Miliary Tuberculosis (TB) is a fatal form of disseminated TB. In childhood it remains a significant health problem in the developing countries. The most common type of TB disease in children is pulmonary TB. While, extra pulmonary TB occurs in approximately 20–30% of all cases in children. Miliary TB accounts for ～1% of all TB cases.We reported a case of pediatric miliary TB in a seven years old female presented with fever associated with sweating, decreased appetite and weight loss. Clinical examination showed hepatospenomegaly and pelviabdominal mass. Laboratory studies revealed anemia and elevated erythrocyte sedimentation rate (ESR) for differential diagnosis. Malignancy was suspected and a panel of radiological scans and histopathological study were done to investigate the mass and to search for other masses elsewhere. The bone marrow and the pelviabdominal mass biopsies were done, and showed normal bone marrow while the mass appeared to be TB granuloma. Tuberculin test, gastric lavage for Ziehl-Neelsen stain (ZN) study for acid-fast bacilli, and Polymerase chain reaction (PCR) test for mycobacterium TB DNA in blood were negative. The ophthalmological screening before commencing anti TB regimen revealed fundus with bilateral small, white sub retinal opacities with the classical appearance of choroidal tubercles. The final diagnosis of miliary TB was made and the patient subsequently started her anti TB therapy in the chest hospital.

Secondary transmission of varicella vaccine virus in a chronic care facility for children

A 16-year-old varicella-seronegative resident at a chronic care facility received varicella vaccine; 15 days later he developed severe varicella. Subsequently, a 13-year-old resident and a 39-year-old health care worker developed mild varicella. We demonstrate that vaccine-strain virus was transmitted to both persons, and that transmission included at least 2 variant vaccine strains.     

Contribution of the polymerase chain reaction to the diagnosis of tuberculous infections in children

Abstract The purpose of the study was to evaluate the contribution of polymerase chain reaction (PCR) to the diagnosis of tuberculous infection in children. Two different PCR techniques were compared to the standard bacteriological methods for the detection ofMycobacterium tuberculosis in 157 specimens obtained from the respiratory system of 51 children. Patients were classified in three groups: 12 patients with active disease (57 specimens), 12 patients with silent tuberculous infection (23 specimens) and 27 patients without tuberculosis (77 specimens). One PCR method (PCR/Ag85) used amplification of a fragment of the genes coding for the mycobacterial antigen 85 followed by hybridization of a probe specific forM. tuberculosis on the Southern blot of amplified DNA. The other PCR technique was a nested PCR (NPCR) using double amplification of a fragment of the insertion element IS6110 only present in theM. tuberculosis genome. The sensitivities of the different techniques, compared to the clinical diagnosis, were 7.0% for acid fast staining, 22.8% for culture, 24.6% for PCR/Ag85 and 44.9% for NPCR in active disease, 4.3% for culture, 8.7% for PCR/Ag85 and 28.6% for NPCR in silent tuberculous infection. The specificities were 100% for culture, 94.8% for PCR/Ag85 and 87.9% for NPCR. Among the 12 children clinically considered as having active tuberculosis, 1 had smear positive samples, 4 had at least one positive culture, 7 at least one positive PCR/Ag85 and 9 at least one NPCR positive sample. Among the 12 children having silent tuberculous infection, none had positive smears, 1 had one positive culture, 2 had at least one positive PCR/Ag85 and 5 at least one NPCR positive sample.Conclusion Our study suggests that both PCR techniques, and especially NPCR, are able to detectM. tuberculosis DNA in specimens containing few micro-organisms. PCR methods are more sensitive than culture and the results are available more quickly. Testing multiple samples from the same individual increased the sensitivity. In view of occasional false-positive results, cultures remain the gold standard to establish definitive diagnosis of primary tuberculous infection in children.     

Homozygosity for TNSALP mutation 1348c>T (Arg433Cys) causes infantile hypophosphatasia manifesting transient disease correction and variably lethal outcome in a kindred of black ancestry

OBJECTIVE: To determine the "tissue-nonspecific" isoenzyme of alkaline phosphatase (TNSALP) defect underlying transiently reversible and variably lethal infantile hypophosphatasia (HPP) in a kindred and to characterize HPP prevalence in black people. STUDY DESIGN: In 1986, we reported temporary correction of severe HPP in an American kindred of black ancestry where "infantile" HPP was fatal in 2 of 3 affected individuals representing 2 sibships. This transient improvement in 1 patient followed efforts to increase TNSALP activity endogenously and suggested dysregulation of the gene (TNSALP). Here, we sequenced the coding exons and splice sites of the kindred's TNSALP alleles and reviewed our 30-year experience with HPP to assess its prevalence in black people. RESULTS: Homozygosity for TNSALP missense mutation 1348C>T (Arg433Cys) accounted for this kindred's infantile HPP. The TNSALP promoter sequence was normal. Modeling of TNSALP(433Cys) suggested compromise of the catalytic site. Ethnicity was identified for the 119 families with HPP studied in St. Louis, and race was ascertained for an additional 159 of our 235 consult and HPP families worldwide. In this experience, only this family was of black ancestry. CONCLUSIONS: Infantile HPP from homozygous TNSALP(433Cys) can remit and thus harbor clues regarding the phenotypic variation and perhaps treatment of HPP.     

Clinical and laboratory features of pertussis in infants at the onset of a California epidemic

We report clinical characteristics and outcome of infants <3 months of age hospitalized with pertussis compared with viral respiratory infection (respiratory syncytial virus and influenza). Patients with pertussis more often were afebrile, had more visits before admission, and had longer hospital stays. Household coughing contacts were common.