Κλινική δ ιάγνωση και πορεία νόσου
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A H1N1 22/09/2009, ,
Influenza The Normal Burden of DiseaseSeasonal InfluenzaGlobally: 250,000 to 500,000 deaths per yearIn the US (per year)~35,000 deaths>200,000 Hospitalizations$37.5 billion in economic cost (influenza & pneumonia)>$10 billion in lost productivityPandemic InfluenzaAn ever present threat
*The situation could be a lot worse for Europe! (Situation circa summer 2009)A pandemic strain emerging in the Americas.Immediate virus sharing so rapid diagnostic and vaccines.Pandemic (H1N1) currently not that pathogenic.Some seeming residual immunity in a major large risk group (older people).No known pathogenicity markers.Initially susceptible to oseltamivir.Good data and information coming out of North America.Arriving in Europe in the summer.Mild presentation in most.A pandemic emerging in SE AsiaDelayed virus sharingBased on a more pathogenic strain, e.g. A(H5N1)No residual immunityHeightened pathogenicityInbuilt antiviral resistanceMinimal data until transmission reached EuropeArriving in the late autumn or winterSevere presentation immediatelyContrast with what might have happened and might still happen!
11- (>100 )
H1N1 / / ARDS
11- :, : , : , ,,, : ., ,
*Seasonal influenza compared to pandemic proportions of types of casesDeathsRequiring hospitalisationSeasonal influenzaPandemicAsymptomaticClinical symptomsDeaths Requiring hospitalisation
Both leukocytosis and leukopenia have been observed among hospitalized patients. In Mexico, many hospitalized patients have had leukopenia, elevated aminotransferases, elevated lactate dehydrogenase, and elevated creatinine phosphokinase. Some patients have also had renal insufficiency. World Health Organization. Human infection with new influenza A (H1N1) virus: clinical observations from Mexico and other affected countries, May 2009. Weekly epidemiological record 2009; 84:185.
, : - - - WHO, Aug. 9, 2009
Rapid antigen tests Clinicians may consider using rapid influenza antigen tests as part of their evaluation of patients suspected of having pandemic H1N1 influenza A, but results should be interpreted with caution . Confirmation of pandemic H1N1 influenza A infection can only be made by real-time reverse-transcriptase (RT)-PCR or culture.
sensitivity 51-63%specificity 99 %
Recommended tests RT-PCR
Swine Influenza A(H1N1) US Case Definitions A confirmed case of swine influenza A (H1N1) virus infection is defined as a person with an acute febrile respiratory illness with laboratory confirmed swine influenza A (H1N1) virus infection at CDC by one or more of the following tests: real-time RT-PCR viral culture
A probable case of swine influenza A (H1N1) virus infection is defined as a person with an acute febrile respiratory illness who is:positive for influenza A, but negative for H1 and H3 by influenza RT-PCR, or positive for influenza A by an influenza rapid test or an influenza immunofluorescence assay (IFA) plus meets criteria for a suspected case
A suspected case of swine influenza A (H1N1) virus infection is defined as a person with acute febrile respiratory illness with onset within 7 days of close contact with a person who is a confirmed case of swine influenza A (H1N1) virus infection, or within 7 days of travel to community either within the United States or internationally where there are one or more confirmed swine influenza A(H1N1) cases, or resides in a community where there are one or more confirmed swine influenza cases. Source: CDC
*Risk groups for the A(H1N1) pandemic 2009The following groups are considered more at risk of experiencing severe disease than the general population should they become infected with the pandemic A(H1N1) virus 2009:
People with chronic conditions in the following categories: chronic respiratory diseases; chronic cardiovascular diseases (though not isolated mild hypertension); chronic metabolic disorders (notably diabetes); chronic renal and hepatic diseases; persons with deficient immunity (congenital or acquired); chronic neurological or neuromuscular conditions; andany other condition that impairs a persons immunity or prejudices their respiratory (breathing) function, including severe or morbid obesity. Note: These categories will be subject to amendment and development as more data become available. These are very similar underlying conditions that serve as risk factors for seasonal influenza. What is especially different from seasonal influenza is that the older age groups (over the age of 60 years) without underlying conditions are relatively unaffected by the pandemic strain.
Pregnant women. Young children (especially those under two years).
ECDC Pandemic 2009 Risk Assessment. Available from: http://www.ecdc.europa.eu/en/Health_topics/novel_influenza_virus/2009_OutbreakFinelli L. CDC Influenza Surveillance. Available from: http://www.cdc.gov/vaccines/recs/ACIP/downloads/mtg-slides-jun09/15-2-inf.pdf Nicoll A et al. Eurosurveillance, Volume 13, Issue 43, 23 October 2008. Available from: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19018 Jamieson D et al. Lancet 2009; July 29, 2009 DOI:10.1016/S0140-6736(09)61304-0CDC 2009 ACIP Meeting, 31 July 2009. Novel influenza A(H1N1) epidemiology update. Available from: http://www.cdc.gov/vaccines/recs/ACIP/downloads/mtg-slides-jul09-flu/02-Flu-Fiore.pdfCDC 2009 ACIP Meeting, 31 July 2009. Vaccine workgroup considerations. Available from: http://www.cdc.gov/vaccines/recs/ACIP/downloads/mtg-slides-jul09-flu/11-Flu-Fiore.pdf
//ARDS , : 15% : 2-5% (?0.3%) (case fatality rate): 0.1-0.2 (0.35) %
Swine Influenza A(H1N1) Mexico Confirmed Cases & Death, by Age GroupsTotal Number of Confirmed Cases = 6,241*Deaths = 108As of June 09, 2009Source: Secretaria de Salud, Mexico*NOTE: 43 confirmed cases not included71.3% Deaths
3/10 BMIARDS median WBC 9500 c/mm3 (4000-10000)10/10 AST median 83 IU/l (41-109)6/10 CPK median 999IU/L (51-6571) 4 (5)/10
oseltamivire ( 150mg X2 /24h)
...the 1918 H1N1 influenza virus pandemic
Severe cases of H1N1 linked to low IgG2 levelsICAAC Sep. 2009
(>37,7 o C) . . .
O H1N1 A, !
**Pandemics come in all shapes and sizes and are highly unpredictable. This slide should be looked at with a later one on Known Knowns and Known Unknowns this slide in particular shows how fortunate we have been so far with this pandemic
******But remember this is idealised and in 2009 in North America this is not putting as many people into Hospital as you would expect from the above. In the 2009 pandemic it is not clear yet what percentage are asymptomatic. Two reasonable estimates are 33% and 50% of the total infected. [Note to Uwe can you increase the asymptomatic fraction in both to make them look about 33% of the total] ********Highest % Case-Fatality (77.5%) was observed in the 20-54 year age group.***************