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SARS in the Emergency Department

SARS in the Emergency Department. Aric Storck PGY2 Resident Oral Presentation February 12, 2004. Outline. The anatomy of an outbreak Diagnosis in the Emergency Department The Calgary Health Region. SARS a unique disease. Don’t know where it came from Spread easily between people

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SARS in the Emergency Department

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  1. SARS in theEmergency Department Aric Storck PGY2 Resident Oral Presentation February 12, 2004

  2. Outline • The anatomy of an outbreak • Diagnosis in the Emergency Department • The Calgary Health Region

  3. SARSa unique disease • Don’t know where it came from • Spread easily between people • No vector required • No geographical affinity • Mimics other diseases • Very effective spread in hospital • Superspreader phenomenon

  4. SARS & the EDa unique challenge • SARS difficult to recognize early in course of illness • Early accurate diagnosis critical in preventing spread and avoidable mortality

  5. the anatomy of an outbreak

  6. November 19, 2002 • First reported case – Fushan, Guandong • November – January, 2003 • Local spread within Guandong • February 11, 2003 • WHO advised of “atypical pneumonia” • 305 sick, 5 dead

  7. February 21 • Doctor from Guangdong checks into ninth floor room in Metropole Hotel in Hong Kong • Elderly woman from Toronto also stays at same hotel

  8. February 23 • Elderly woman returns to Toronto • Falls ill shortly after • Cared for at home by her son • Another guest travels to Vietnam • 13 cases subsequently linked to index case at Metropole Hotel

  9. March 5 March 7 Patient B falls sick and presents to hospital Patient A dies at home Source: Mcgeer A. The Toronto outbreak. (Accessed January 31, 2004 at http://www.niaid.nih.gov/sars/meetings/05_30_03/pdf/mcgeer.pdf

  10. March 7, 2003Emergency Department • Patient C • Rapid atrial fibrillation • In bed 1.5 metres away from B • Separated by curtain • Discharged home after nine hours • Patient B presents with respiratory symptoms • Received nebulized salbutamol • admitted • Patient D • Pleural effusion/SOB • 5 metres away from B • Admitted then d/c’d home March 10 B,C,D all cared for by same nurse Source: Mcgeer A. The Toronto outbreak. (Accessed January 31, 2004 at http://www.niaid.nih.gov/sars/meetings/05_30_03/pdf/mcgeer.pdf

  11. March 8 • Patient B transferred to ICU • Airborne isolation precautions initiated – concerned about TB • March 10 • Contact precautions initiated • March 12 • WHO alerts world to “severe atypical pneumonia” (SARS) • March 13-14 • “B” dies • Five family members admitted to three different hospitals

  12. Back to our atrial fibber • Remember …. • March 7 – discharged from ED • March 10 • became febrile • March 16 • To hospital via EMS • 9 hours in ED (all isolation precautions used) • “C”s wife falls ill • March 21 • “C” dies in ICU

  13. Source: Mcgeer A. The Toronto outbreak. (Accessed January 31, 2004 at http://www.niaid.nih.gov/sars/meetings/05_30_03/pdf/mcgeer.pdf

  14. Source: Mcgeer A. The Toronto outbreak. (Accessed January 31, 2004 at http://www.niaid.nih.gov/sars/meetings/05_30_03/pdf/mcgeer.pdf

  15. Wife Two other family members Two paramedics One firefighter 5 ED staff 2 other hospital staff 2 ED patients 7 visitors to ED ICU MD during intubation Transmitted to one member of family 3 ICU nurses at intubation One family member infected People “C” infected

  16. What about the fellow with the pleural effusion? • March 13 • “D” falls ill – Symptoms resemble MI • Brought to ED by EMS • No precautions initiated • Admitted to CCU

  17. Source: Mcgeer A. The Toronto outbreak. (Accessed January 31, 2004 at http://www.niaid.nih.gov/sars/meetings/05_30_03/pdf/mcgeer.pdf

  18. Patient “D” • Develops renal failure • Transferred to another hospital for dialysis

  19. Source: Mcgeer A. The Toronto outbreak. (Accessed January 31, 2004 at http://www.niaid.nih.gov/sars/meetings/05_30_03/pdf/mcgeer.pdf

  20. His wife 1 ED patient 3 ED staff 1 housekeeper 1 physician 2 hospital technologists 2 CCU patients 7 CCU staff 1 paramedic Transmission from those to 6 family members 1 patient 1 medical clinic staff 1 ED nurse People “D” infected

  21. 21 ED staff infected • 3 prehospital staff Source: CMAJ Aug. 19, 2003

  22. Worldwide 29 countries 8422 cases 908 fatalities Canada 438 cases 250 probable 188 suspect 375 in Ontario November 2002 – May 2003the final tally

  23. Attack Rates • Emergency Department Nurses • Six 12-hour unprotected shifts where SARS exposure possible • 22.2% (8/36) • 13.6 cases per 1000 nursing hours • ICU Nurses • 3 unprotected hours • 10.3% (4/39) • 2.4 cases per 1000 nursing hours • CCU Nurses • 6 unprotected shifts • 60% (6/10) • 31.3 cases per 1000 nursing hours Source: CMAJ Aug. 19, 2003

  24. So how do we recognize SARS in the Emergency Department?

  25. WHO Case Definition of SARSSuspect CaseRevised May 1, 2003 • A person presenting after November 1, 2002 with history of: • high fever (>38 °C) • AND • cough or breathing difficulty • AND one or more of the following exposures during the 10 days prior to onset of symptoms: • close contact with a person who is a suspect or probable case of SARS • history of travel, to an area with recent local transmission of SARS • residing in an area with recent local transmission of SARS

  26. WHO Case Definition of SARSProbable Case • A suspect case with radiographic evidence of infiltrates consistent with pneumonia or ARDS on CXR • A suspect case that is positive for SARS coronavirus by one or more assays • A suspect case with autopsy findings consistent with the pathology of RDS without an identifiable cause

  27. Is the WHO definition useful in the Emergency Department? • Criticisms • Based on studies of patients already in hospital • Based on common symptoms • Difficult to determine contact history • How accurate is it?

  28. Rainer, et al. Evaluation of WHO criteria for identifying patients with SARS out of hospital: prospective observational study. BMJ 2003; 326: 1354-8. • Objectives • Determine clinical and radiological features of SARS • Evaluate accuracy of WHO case definition • Who • 556 hospital staff, patients, relatives who had contact with confirmed SARS patient • Where • SARS screening clinic in ED of tertiary care hospital in Hong Kong • Outcome • Confirmed cases of SARS defined by • Known contact with SARS patient • Persistent fever (>38) • Evidence of pneumonia • Consistent course of illness • Did not respond to antibiotics within 48 hours • NB: serological testing not available at this time

  29. Symptoms more common among patients who did not develop SARS • Cough - 72% vs 64% p=0.12 • Sputum production – 29% vs 26% p=0.52 • Sore throat – 39% vs 35% p=0.53 • Runny nose – 33% vs 26% p=0.20

  30. Symptoms Fever – 81% vs 37% Chills – 54% vs 21% Malaise – 34% vs 20% Myalgia – 27% vs 12% Rigor – 12% vs 4% Neck pain - 3% vs 0.2% loss of appetite 5% vs 1% SOB – 12% vs 7% Vomiting – 6% vs 2% Diarrhea – 7% vs 3% Signs Higher heart rate Lower sBP Higher temp No difference in RR NB: of respiratory symptoms only SOB was significant Significant findings more common among SARS patients(p<0.05)

  31. Predictive value of WHO criteria

  32. Odds ratios for predicting SARS • Fever 12.0 (6.8-21.0) • Cough 1.0 (0.6-1.7) • SOB 1.5 (0.7-3.5) • CXR infiltrate 32.1 (18.0-57.3)

  33. Conclusions • WHO criteria is based on respiratory symptoms which are uncommon in early SARS • WHO criteria miss 74% of SARS cases in the pre-hospital setting • Radiological infiltrates often proceed fever in early SARS - thus CXR mandatory for SARS screening

  34. Wong W, et al. Accuracy of clinical diagnosis versus the WHO case definition in the Amoy Garden SARS cohort. CJEM 2003;5(6):384-91. • Objective • Compare WHO case definition with ED physician clinical diagnosis • Who • Retrospective cohort of 818 residents of Amoy Gardens presenting to a SARS screening clinic during a 2 month outbreak

  35. Amoy Gardens • Largest community outbreak in world • 323 resident cases • 37 deaths • 18% of all Hong Kong cases • Spread linked to • Faulty sewage • Poor ventilation

  36. Outcomes • Confirmed SARS • Clinical SARS and virological confirmation • Undetermined • Clinical SARS without virology confirmation (lab testing not performed or incomplete) • Non-SARS • Final diagnosis unrelated to SARS

  37. Results • SARS – 205 cases • Undetermined SARS – 35 cases • Non-SARS – 581 cases • NB: disease prevalence = 26% in study population

  38. Confirmed SARS (n = 205) Non-SARS (n = 581) No. (and %) No. (and %) Confirmed SARS (n=205) Non-SARS (n=581)

  39. Diagnostic accuracy of WHO case definition • Sensitivity 42.4% • Specificity 86.4% • Accuracy 74.9% • PPV 52.7 • NPV 80.8 • NB: 6 patients charts incomplete

  40. Diagnostic Accuracy of ED diagnosis • Sensitivity 90.7% • Specificity 95.7% • Accuracy 94.4% • PPV 88.2% • NPV 96.7%

  41. Conclusions • WHO definition would miss 58% of SARS • Clinical judgement superior to WHO criteria • Caveats • Extremely high disease prevalence would affect PPV/NPV

  42. So if the WHO criteria doesn’t work in the ED, how do I recognize SARS?

  43. Wong W, et al. Early clinical predictors of SARS in the ED. CJEM 2004;6(1):xx • Objectives • To assess diagnostic predictors available in the ED with final diagnosis of SARS • Who • Same cohort as previous study

  44. Conclusions • WHO case definition not sufficiently sensitive or specific to guide disposition • Positive predictors • Fever, lymphopenia, abnormal CXR, thrombocytopenia, myalgia, chills • Negative predictors • Diarrhea • Cough and dyspnea not useful predictors in the ED

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