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Query: UMLS:C0027121 (myositis)
 4,538 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Influenza viruses represent Orthomyxoviridae family. Spherical virions are 80-120 nm in diameter and have two-layer lipid envelope. The following proteins are coded by 8 or 7 segments of the single-stranded RNA: nucleoprotein (NP), polymerase PB2, PB1 and PA, member protein--M1 and M2, glycoproteins--hemagglutinin (HA) and neuraminidase (NA). HA and NA form spikes on the virion surface. On the basis of antigenic differences there are distinguished three types of influenza virus-A, B and C. Besides, influenza A viruses occur in different subtypes, depending on the features of HA and NA. One of influenza characteristics is its antigenic changeability: antigenic drift and antigenic shift. Infection occurs by droplet route, sometimes through direct contact with infected person or surface. Influenza virus attacks epithelial cells of upper respiratory tract, where replication takes place resulting in the production of approximately 1000 of progeny virions during a single 6-12 h cycle in one cell. Necrosis of ciliary cells of mucosa facilitates invasion of bacterial pathogens. Incubation period lasts on average 1-2 days. Influenza illness without complications characterizes the sudden onset of respiratory symptoms and systemic symptoms. Regression of symptoms usually occurs after 3-5 days, but cough and malaise may be observed for over 2 weeks. Reasons for the severe course of the disease or even death are post-influenza complications, e.g. viral pneumonia and bronchitis, bronchiolitis in children, secondary bacterial pneumonia, otitis media, myocarditis and pericarditis, Reye's syndrome, myositis, myoglobinuria, neurological complications and exacerbation of existing chronic diseases. In the case of influenza there is no possible to make the unquestionable diagnosis only on the basis of clinical picture of the disease. Therefore in some circumstances there is important to make some diagnostic laboratory tests as RT-PCR, immunofluorescence assay or isolation of virus and detection of the specific antibodies. The main determinants of the immunity to influenza virus infection are antihemagglutinin (anti-HA) antibodies and antineuraminidase antibodies (anti-NA). The former play fundamental role for the protection against the infection, while anti-NA antibodies limit virus spreading and contribute to a milder course of the disease. In the response to influenza infection there are observed serum immunoglobulines IgG and IgM (after the first contact with the antigen), while immunoglobulines IgA are produced rarely. The latter are produced locally in the high concentrations on the mucus of respiratory tract. Cellular immunological response is important for recovery from influenza where a significant role of cytotoxic T lymphocytes should be emphasized. These lymphocytes are able to kill infected cells in the earliest phases of replication before the progeny virions are formed.
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PMID:[Various sides of influenza, part I--structure, replication, changeability of influenza viruses, clinical course of the disease, immunological response and laboratory diagnostics]. 1716 90

Myocarditis, a general inflammatory condition of the heart muscle, can result from a variety of etiologies, the most common being viral. Despite common pathogens, concomitant myocarditis and myositis remains a rare event. Although a common cause of respiratory illness, extrapulmonary infections with influenza are infrequent. We describe the case of a patient who presented to our centre with concomitant "seasonal" H1N1 influenza A myocarditis further complicated by pan-myositis. The patient's condition rapidly declined, eventually requiring biventricular mechanical support, in addition to multilimb fasciotomies. The cardiac support required was progressive, from a percutaneous left ventricular assist device, to extracorporeal membrane oxygenation, to eventual biventricular assist device support for bridge-to-transplantation. This case motivated a detailed review of the literature (a total of 29 cases were identified), in which we found that patients with influenza myocarditis/myositis were predominantly female (63%) and young (mean age 33.2 years) and continue to have a high incidence of morbidity and mortality (27%). As a result of its atypical pattern, the 2009 H1N1 pandemic strain has gained attention. From our review, we found 7 patients with of 2009 H1N1 pandemic influenza myocarditis. Serial serum cytokine analysis did not demonstrate a "cytokine storm," which has been associated with other virulent influenza strains. The PB1-F2 marker in particular has been associated with a vigorous cytokine response. The 2009 H1N1 and "seasonal" influenza strains lack this marker. In those patients with community-acquired influenza, interleukin-6 has been shown to correlate with symptoms. For patients with myocarditis resulting in shock, mechanical circulatory support has gained acceptance as a means to recovery or transplantation.
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PMID:Influenza myocarditis and myositis: case presentation and review of the literature. 2165 68