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Published in Samar Razaq, Difficult Cases in Primary Care, 2021
This is the typical presentation of roseola infantum. Other names for this condition include sixth disease (a historical reference to the six rash-causing illnesses of childhood), exanthema subitum and 3-day fever. The rash appears as the child improves in his or her condition and most parents will tell you that they would not have come to see you had the rash not appeared. Parvovirus B19 causes slapped cheek syndrome, also known as fifth disease.
Diagnostic Approach to Fulminant Hepatitis in the Critical Care Unit
Published in Cheston B. Cunha, Burke A. Cunha, Infectious Diseases and Antimicrobial Stewardship in Critical Care Medicine, 2020
Human herpesvirus-6 (HHV-6) consists of a set of two closely related herpesviruses known as HHV-6A and HHV-6B that almost invariably have humans as their primary host. The seroprevalence of HHV-6 among the adult population is as high as 82%–100%, even though primary infection is rare [23]. The virus is a common cause of liver dysfunction and ALF, especially in the immunosuppressed transplant patient. The HHV-6 infection often causes exanthema subitum in infants and a mononucleosis-like syndrome in adults. Pretransplant HHV-6 infection and concurrent CMV infection are identified risk factors associated with liver dysfunction following hepatic transplantation [24]. The diagnosis of HHV-6 infection can be made based on a positive HHV-6 serum antigen test (monoclonal antibodies against specific HHV-6A and -B antigens as well as a polyclonal antibody against HHV-6 U90 protein), which detects the presence of the virus in peripheral blood mononuclear cells, the presence of HHV-6 antigens on liver biopsy, or the demonstration of HHV-6 serology (IgG or IgM anti-HHV-6) by means of indirect EIA. A greater than fourfold rise in IgG titers is considered diagnostic, as most people are seropositive for HHV-6 IgG. While anti-HHV-6 develops within 4–7 days of infection, it may be unreliable, as IgM can be falsely positive in healthy adults [23]. Foscarnet, ganciclovir, and cidofovir may be used to treat acute disease [25].
Systemic Physical Condition
Published in A. Sahib El-Radhi, Paediatric Symptom and Sign Sorter, 2019
Exanthema subitum (caused by HH-6; Figure 3.1) is the most common febrile exanthem in children younger than 3 years, occurring in about 30% of children. Onset of fever is abrupt and characteristically continuous, often as high as 40°C–41°C, and without a focus. Characteristically, the child becomes well and afebrile when the rash erupts.
Prevention and treatment of temporal lobe epilepsy: lessons from hepatitis B story!
Published in International Journal of Neuroscience, 2020
Ali A. Asadi-Pooya, Luca Bartolini
Human herpes virus-6 (HHV-6) has been linked to TLE in humans [7,8]. There are two viral species HHV-6A and B; they share 90% homology [7]. It is an enveloped DNA virus that belongs to the β-herpesviridae family [7]. HHV-6 has both neuro-invasive and pro-inflammatory properties, with the ability to infect astrocytes and oligodendrocytes leading to increased production of various inflammatory mediators, such as IFN-α and TNF-α [7]. There are several studies confirming the detection of HHV-6 DNA in hippocampal brain tissue of patients with HS-TLE [7–9]. The primary viral infection often occurs in early life and results in a self-limited febrile illness; in a portion of children Roseola Infantum (Exanthema Subitum or Sixth Disease) develops [10]. This is followed by life-long latency of the virus in various cell lines, including neural cells [11]. The mechanisms by which latent HHV-6 infection reactivates or causes damage from persistent subclinical active infection are not completely understood [7]. The relationship between HHV-6 and HS-TLE could be attributed to the epigenetic modifications and integration of the virus in the chromosome that might cause dysregulation of neuronal cells that reduces their capacity to regulate neurotransmitters [8,12]. Alterations in blood brain barrier permeability and also direct neuronal damage and death are other possible mechanisms by which HHV-6 may cause epilepsy [7,13].
Reactivation of human herpesviruses 6 and 7 in Kawasaki disease
Published in Modern Rheumatology, 2019
Yoshihiko Kawano, Jun-ichi Kawada, Noriko Nagai, Yoshinori Ito
This study utilized multiplex real-time PCR assays to investigate the association between HHV-6/-7 and KD. Generally, HHV-6 or -7 reactivation is defined as an increase in IgG antibody titer against the respective virus. However, this definition could not be used in the present study because all patients received IVIG for treatment of KD. We therefore defined HHV-6 and -7 reactivation as increased viral loads in seropositive patients. We found that increased HHV-6 and -7 DNA loads were observed in 47% and 60% of seropositive patients, respectively, suggesting that reactivation of HHV-6 and -7 frequently occurred in KD patients. Furthermore, one patient was considered to have primary HHV-6 infection. A few reports have shown KD patients in whom HHV-6 was isolated from peripheral blood or who had increased IgG antibody titers against HHV-6 (2) [11]. Regarding HHV-7, only one study has demonstrated seroprevalence of HHV-7 in KD patients [3]. Presently, HHV-6 and -7 are not considered to be the direct cause of KD. It is difficult to conclude that HHV-6 or -7 causes KD because these viruses are ubiquitous and the age distributions of exanthema subitum and KD overlap. Nevertheless, it might be possible that primary infection or reactivation of HHV-6 or -7 might affect the clinical features of KD.
Time-series analysis: variation of anti-acetylcholine receptor antibody titer in myasthenia gravis is related to incidence of Mycoplasma pneumoniae and influenza virus infections
Published in Neurological Research, 2018
Kazuo Iwasa, Hiroaki Yoshikawa, Tsuyoshi Hamaguchi, Kenji Sakai, Moeko Shinohara-Noguchi, Miharu Samuraki, Kazuya Takahashi, Daisuke Yanase, Kenjiro Ono, Chiho Ishida, Mitsuhiro Yoshita, Hiroyuki Nakamura, Masahito Yamada
Data regarding the incidence of infectious diseases were obtained from Ishikawa Infectious Diseases Surveillance Center, Infectious Diseases Surveillance Program in Japan. The intended infections were by Mycoplasma pneumoniae, influenza virus, respiratory syncytial virus, Group A beta-hemolytic streptococci, varicella zoster virus, hand foot and mouth disease, exanthema subitum, Bordetella pertussis, mumps virus, and herpangina. These surveilled patients were drawn from 29 monitoring hospitals in Ishikawa prefecture every week, and the 29 monitoring hospitals covered all of Ishikawa prefecture. The data from August 2006 to October 2012 are available at http://www.pref.ishikawa.lg.jp/kansen/index.html. In this study, the number of patients with infections was calculated as follows: number of observed patients/29 monitoring points for M. pneumoniae, respiratory syncytial virus, exanthema subitum, and B. pertussis; number of observed patients/10 of the 29 monitoring points for Group A beta-hemolytic streptococci, varicella virus, hand foot and mouth disease, mumps virus, and herpangina; and number of observed patients/100 for the 29 monitoring points for influenza virus. Seasonal variations in the number of each infection per month were calculated using a three-term moving average.