Kyung Wook Hong

Etiology and Clinical Outcomes of Acute Respiratory Virus Infection in Hospitalized Adults

Background Etiologies and clinical profiles of acute respiratory viral infections need to be clarified to improve preventive and therapeutic strategies. Materials and Methods A retrospective observational study at a single, university-affiliated center was performed to evaluate the respiratory viral infection etiologies in children compared to that in adults and to document the clinical features of common viral infections for adults from July 2009 to April 2012. Results The common viruses detected from children (2,800 total patients) were human rhinovirus (hRV) (31.8%), adenovirus (AdV) (19.2%), respiratory syncytial virus (RSV) A (17.4%), RSV B (11.7%), and human metapneumovirus (hMPV) (9.8%). In comparison, influenza virus A (IFA) had the highest isolation rate (28.5%), followed by hRV (15.5%), influenza virus B (IFB) (15.0%), and hMPV (14.0%), in adults (763 total patients). Multiple viruses were detected in single specimens from 22.4% of children and 2.0% of adults. IFA/IFB, RSV A/B, and hMPV exhibited strong seasonal detection and similar circulating patterns in children and adults. Adult patients showed different clinical manifestations according to causative viruses; nasal congestion and rhinorrhea were more common in hRV and human coronavirus (hCoV) infection. Patients with RSV B, hRV, or AdV tended to be younger, and those infected with RSV A and hMPV were likely to be older. Those with RSV A infection tended to stay longer in hospital, enter the intensive care unit more frequently, and have a fatal outcome more often. The bacterial co-detection rate was 26.5%, and those cases were more likely to have lower respiratory tract involvement (P = 0.001), longer hospital stay (P = 0.001), and higher mortality (P = 0.001). Conclusions The etiologic virus of an acute respiratory infection can be cautiously inferred based on a patients age and clinical features and concurrent epidemic data. Large-scale prospective surveillance studies are required to provide more accurate information about respiratory viral infection etiology, which could favorably influence clinical outcomes.

Utility of the Montreal Cognitive Assessment (MoCA) and its subset in HIV-associated neurocognitive disorder (HAND) screening

OBJECTIVES The Montreal Cognitive Assessment (MoCA) is a useful screening tool for mild cognitive impairment. We aimed to know whether the full MoCA and subsets of the full test are effective for detecting HIV-associated neurocognitive disorder (HAND). METHODS We examined the socio-demographic, clinical, functional, and neuropsychological levels of 194 HIV-infected patients. We compared total scores and scores from each cognitive domain of MoCA between patients with and without HAND. We also examined the utility of subsets of the full test using a few selective domains. The diagnostic accuracies of MoCA and subset composition were evaluated. RESULTS The total scores of MoCA (P<0.001) and scores from Trail Making Test-B (P=0.020), attention domain (P=0.005), and immediate (P=0.003) and delayed recall (P=0.002) differed between patients with and without HAND. A subset composed of Trail Making Test-B, rescored serial subtraction, and immediate/delayed recall showed a 69.2% accuracy. CONCLUSIONS Our results suggest that the MoCA and its subsets alone are not sufficient in screening for HAND. Further studies will be needed to develop a simpler and easier screening tool for HAND based on this study.

Clinical Manifestations of Influenza A and B in Children and Adults at a Tertiary Hospital in Korea during the 2011–2012 Season

This study aims to evaluate and compare the epidemiological patterns and clinical courses of influenza A and B among children and adults. For this purpose, we retrospectively reviewed the medical records of 809 children and 271 adolescents/adults with laboratory-confirmed influenza between October 2011 and May 2012 at a tertiary-care hospital. Children with influenza B presented with high fever (body temperature >39℃), sputum production, diarrhea, nausea/vomiting, and myalgia more frequently than those with influenza A. Children with influenza B also showed longer intervals from symptom onset to the initiation of antivirals and higher rates of antibiotic prescription and hospitalization than those with influenza A. Adults aged 20-59 years accounted for approximately 16% and 20% of patients with influenza A and B, respectively. Although clinical manifestations and outcomes were similar between adult patients with influenza A and those with influenza B, influenza B may cause substantial disease burden among not only children but also socially active adults aged 20-59 years.

Pulmonary toxocariasis mimicking invasive aspergillosis in a patient with ulcerative colitis.

A 45-year-old-male who had underlying ulcerative colitis and presented with fever and dry cough. Initially, the patient was considered to have invasive aspergillosis due to a positive galactomannan assay. He was treated with amphotericin B followed by voriconazole. Nevertheless, the patient deteriorated clinically and radiographically. The lung biopsy revealed eosinophilic pneumonia, and ELISA for Toxocara antigen was positive, leading to a diagnosis of pulmonary toxocariasis. After a 10-day treatment course with albendazole and adjunctive steroids, the patient recovered completely without any sequelae. Pulmonary toxocariasis may be considered in patients with subacute or chronic pneumonia unresponsive to antibiotic agents, particularly in cases with eosinophilia.

Perceptions of tetanus-diphteria-acellular pertussis (Tdap) vaccination among Korean women of childbearing age

Background The number of cases of pertussis reported has increased gradually in the last decade. Pertussis vaccination is the most effective strategy for the prevention of infection. Despite the fact that young infants are at the highest risk for pertussis, the rate of tetanus-diphtheria-acellular pertussis (Tdap) vaccination is presumed to be very low among women of childbearing age in Korea. The purpose of this study was to investigate the perceptions of women of childbearing age regarding Tdap vaccination in Korea. Materials and Methods Women of childbearing age, who visited the Department of Obstetrics and Gynecology at 3 University hospitals in the Seoul and Gyeonggi-do provinces of Korea, were surveyed. Individual questionnaires were administered from April to May 2012. Demographic data, Tdap vaccination history, general knowledge about pertussis, and information on factors associated with decision on vaccination were collected. Results Of the 500 reproductive-age women enrolled, only 4 (0.8%) had received the Tdap. The most common reason for non-vaccination was the lack of awareness of pertussis and information about the Tdap. Totally, 171 (34.2%) responded that they would receive a Tdap vaccination in the future. By multivariate analysis, general confidence in the effectiveness of the vaccine (odds ratio [OR] = 1.88, 95% confidence interval [CI] 1.17 to 3.01) was indicated as an important factor for deciding whether to receive the Tdap vaccine (P < 0.01). Conclusions The coverage of Tdap vaccination of women of childbearing age, including pregnant women, is very low because of the lack of awareness of pertussis and the Tdap. Education of women of childbearing age about pertussis is very important to increase Tdap vaccination rates among these women, particularly during the perinatal period.

Phylogenetic relationships of the HA and NA genes between vaccine and seasonal influenza A(H3N2) strains in Korea

Seasonal influenza is caused by two influenza A subtype (H1N1 and H3N2) and two influenza B lineage (Victoria and Yamagata) viruses. Of these antigenically distinct viruses, the H3N2 virus was consistently detected in substantial proportions in Korea during the 2010/11-2013/14 seasons when compared to the other viruses and appeared responsible for the influenza-like illness rate peak during the first half of the 2011/12 season. To further scrutinize possible causes for this, we investigated the evolutionary and serological relationships between the vaccine and Korean H3N2 strains during the 2011/12 season for the main antigenic determinants of influenza viruses, the hemagglutinin (HA) and neuraminidase (NA) genes. In the 2011/12 season, when the number of H3N2 cases peaked, the majority of the Korean strains did not belong to the HA clade of A/Perth/16/2009 vaccine, and no Korean strains were of this lineage in the NA segment. In a serological assay, post-vaccinated human sera exhibited much reduced hemagglutination inhibition antibody titers against the non-vaccine clade Korean H3N2 strains. Moreover, Korean strains harbored several amino acid differences in the HA antigenic sites and in the NA with respect to vaccine lineages during this season. Of these, the HA antigenic site C residues 45 and 261 and the NA residue 81 appeared to be the signatures of positive selection. In subsequent seasons, when H3N2 cases were lower, the HA and NA genes of vaccine and Korean strains were more phylogenetically related to each other. Combined, our results provide indirect support for using phylogenetic clustering patterns of the HA and possibly also the NA genes in the selection of vaccine viruses and the assessment of vaccine effectiveness.

Acute myopericarditis caused by human metapneumovirus

Human metapneumovirus is known to be similar to respiratory syncytial virus. Because of an incomplete protective immune response to new genotypes, re-infection occurs frequently, especially in the elderly. However, the clinical manifestations of human metapneumovirus need to be further characterized in adults. A 73-year-old woman presented to the emergency room with acute dyspnea, chest discomfort and influenza-like illness. The patient was diagnosed with human metapneumovirus infection, complicated by pneumonia and myopericarditis. With supportive care including oxygen supplementation, the patient recovered completely without any serious sequelae. Human metapneumovirus infection may contribute to the development of cardiovascular manifestations, particularly in the elderly population.