Term
| how do viral resp infections compare to bacterial ones? |
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Definition
| viral resp infections are more common, generally less severe, remain localized (no dissemination), re-infection is common and the symptoms are treated |
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Term
| why is reinfection common with viral resp infections? |
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Definition
| viral infections are poor inducers of immunity due to a short duration of immune response, *antigenic variation (influenza) and *multiple serotypes (rhinoviruses/adenoviruses) |
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Term
| what characterizes a clinical cold infection? |
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Definition
| sore throat, stuffy nose, runny nose (rhinorrhea), sneezing, and coughing. symptoms (due to immune response) appear 8-12 hrs post infection and peak 1-3 days. self resolution usually occurs after 7-11 days. |
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Term
| how can respiratory viruses induce airway hyper-responsiveness? |
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Definition
| this is due to influx of inflammatory cells, release of proinflammatory cytokines (neutrophil/eosinophil chemoattractants), and edema (these can all set up an easier infection by bacteria) |
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Term
| how are clinical resp viral infections sometimes characterized? |
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Definition
| as ILI, or influenza-like illness: fever, myalgia, headache, fatigue, sore throat, and chest discomfort which occur a more *w/sudden onset than colds - after about a 3 day incubation period |
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Term
| what is one of the most common complications w/the resp viral infections? |
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Definition
| bacterial superinfections: sinusitis, otitis media, bacterial pneumonia - mainly due to strep pneumonia/haemophilus influenza/staph aureus |
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Term
| how are upper respiratory tract viral infections diagnosed? |
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Definition
| clinically by cx/serology, but usually this doesn't even happen b/c the illness is self-limiting. *however group A strep need to be r/o. |
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Term
| how are lower respiratory tract viral infections diagnosed? |
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Definition
| it may be useful to differentiate between RSV and influenza in a child as well as determination of the influenza type for epidemiological/vaccine purposes |
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Term
| what are the symptoms of rhinitis? |
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Definition
| runny nose, stuffy nose, sneezing cough |
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Term
| what are the common viral agents responsible for rhinitis? |
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Definition
| rhinovirus, coronavirus, parainfluenza, RSV (less commonly influenae/enteroviruses: coxsackie A/echoviruses) |
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Term
| what is the symptom of phayngitis? common viral agents responsible? |
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Definition
| sore throat - due to adenovirus, EBV (less commonly: HSV/coxsackie A) |
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Term
| what are the symptoms of laryngitis? common viral agents? |
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Definition
| hoarseness, cough, sore throat. influenza/parainfluenza (less common: RSV, coxsackie A21) |
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Term
| what are the symptoms of laryngotracheo-bronchitis (croup)? common viral agents? |
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Definition
| barking cough, inspiratory stridor, hoarseness, fever, tachypnea. parainfluenza (less commonly: RSV, influenza) |
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Term
| what are the symptoms of tracheobronchitis? common viral agents? |
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Definition
| cough, fever, rhonci, rales, substernal pain. influenza, adenovirus, RSV, parainfluenza. (less common: coxsackie A21, measles) |
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Term
| what are the symptoms of bronchitis (children <2)? common viral agents? |
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Definition
| cough, dyspnea, wheezing, tachypnea, tachycardia. RSV, parainfluenza (less common: adenovirus, influenza) |
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Term
| what are the symptoms of pneumonia? common viral agents? |
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Definition
| cold, fever, rigors, myalgias, headache, substernal pain. influenze, adenovirus, RSV, parainfluenza. |
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Term
| what kind of virus is rhinovirus? |
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Definition
| picronavirus, RNA, naked and icosahedral. *acid labile (does not survive GI), *grows best at 33 C (cooler in URT), and is the *most frequent cause of the common cold - usually in the fall and spring. there are >100 subtypes, so its easy to get reinfected by a slightly different subtype |
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Term
| what kind of virus is the coronavirus? |
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Definition
| nidovirales family, RNA virus, *enveloped/helical, and is the *second most frequent cause of the common cold - usually seen in the winter |
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Term
| is SARS a kind of coronavirus? |
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Definition
| yes, SARS (severe acute respiratory syndrome) had a big outbreak in china/canada in 2004, apparently uses bats as a reservoir and hasn't really been seen since. |
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Term
| what are the clinical features of SARS? |
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Definition
| incubation period of 2-10 days, early systemic symptoms, lower RT symptoms dry cough, shortness of breath and development of CXR confirmed pneumonia by day 7-10 |
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Term
| what kind of virus is the adenovirus? |
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Definition
| DNA (more latent, persistent infection potential), naked, icosahedral: *can survive in the GI tract - can spread through fecal/oral/respiratory routes* |
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Term
| what is the most common disease due to adenovirus? who is most commonly infected? can it become latent? |
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Definition
| severe pharyngitis, conjunctivitis, pharyngoconjuctival fever, ARD, and pneumonia (also acute hemorrhagic cystitis, and gastroenteritis). adenovirus infections are more common in children than adults and can become fatal in the adenoids/tonsils |
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Term
| what characterizes pharyngitis due to adenovirus? |
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Definition
| it may mimic strep throat, but flu-like symptoms (nasal congestion, cough, coryza, fever, myalgia, headache) are seen with it as well. typically in children older than 3, the pharynx and conjunctiva are affected (<3, pharynx alone) - therefore it is often referred to as "swimming pool conjunctivitis" |
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Term
| what characterizes the ARD (acute respiratory disease) associated with adenovirus? |
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Definition
| fever, cough, pharyngitis, adenitis - often seen in military recruits (vaccine existed, but was discontinued) |
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Term
| what does the paramyxoviridae family consist of? |
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Definition
| paramyxovirus (parainfluenza 1-4, mumps), mobillivirus (measles), pneumovirus (RSV), and metapneumovirus (human metapneumovirus) |
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Term
| who are more severe paramyxovirus infections associated with? |
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Definition
| young children and the elderly |
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Term
| what is the metapnuemovirus? |
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Definition
| a virus IDed in 2001, associated with respiratory disease similar to RSV and most children are seropositive by 5 |
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Term
| what level of pneumonia in children is RSV responsible for? |
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Definition
| respiratory syncytial virus is the leading cause of pneumonia (50%) and bronchiolitis (75%) in young children. most children have been infected by age 2, and reinfection is common but less severe. it is usually seen nov-apr |
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Term
| who is at the highest risk for RSV infection? |
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Definition
| premature infants, children 1-3 mos, children w/underlying cardiac/pulmonary disease, immunosuppressed pts, and the elderly |
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Term
| what 2 antivirals can be administered for severe RSV? |
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Definition
| ribavirin and palivizumab |
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Term
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Definition
| an analogue of guanosine that gets incorporated into viral transcription, causing a lot of mistakes. it needs to be activated by phosphorylation and is clinically effective against RSV, lassa fever virus and HCV (along w/IFN-alpha) |
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Term
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Definition
| a humanized murine monoclonal antibody. it binds the epitope on the viral F (fusion) protein. this prevents the virus from fusing and is used to prevent RSV in high risk pediatric pt |
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Term
| is there a vaccine available for RSV? |
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Definition
| no b/c children have an immature immune response, the maternal antibodies may still be present, and the inactivated vaccine that was tried in the 50s produced a more severe disease |
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Term
| what kind of resp infections are the parainfluenza viruses responsible for? when are they seen? |
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Definition
| croup in infants and bronchiolitis/pneumonia in young children. it is usually present in the late fall/winter. (less severe than RSV) |
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Term
| what genuses are members of the picornavirus family that cause resp infections? |
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Definition
| enterovirus (coxsackieviruses A, echoviruses) and rhinoviruses |
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Term
| what kind of viruses are enteroviruses? |
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Definition
| RNA, naked, isosahedral. they are stable at acidic pH, and can survive the oropharynx and GI (spread fecal/orally/respiratory). they are seen in the summer/early fall and inculde coxsackie A and echovirus. |
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Term
| what kind of viruses are the hantaviruses? what kind of disease do they cause? |
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Definition
| hantaviruses, of which bunyavirus is one are trisegmented, RNA, helical and enveloped. the asian strains of hanta viruse can cause hemorrhagic fever w/renal syndrome (HFRS) and the US strain can cause hantavirus pulmonary syndrome (HPS) and is associated with field mouse droppings/saliva/feces (not person-person) and a high fatality rate (sin nombre). |
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Term
| what are the early symptoms of the hantavirus pulmonary syndrome associated with? late? |
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Definition
| early: fever, chills, myalgia, headache, N/V, diarrhea. late (4-10 days later): cough, dyspnea, acute pulmonary congestion, edema, diffuse interstitial infiltrates, hypoxia, shock, death. *there is a rapid progression, usually requiring mechanical ventilation w/in 24 hrs |
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Term
| what are clinical markers for hanatvirus pulmonary syndrome? |
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Definition
| a elevated hematocrit (fluid shift from the pts circulation to the lungs), WBC count will be elevated, and thrombocytopenia |
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