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Infections in Accident and emergency. Philip G. Murphy Consultant in Medical Microbiology, AMNCH Clinical Professor, TCD Tel. ext. 3919 philip.murphy@amnch.ie. Lecture objectives. Integrate Microbiology knowledge to A&E Doctor Consider factors unique to A & E dept Vs GP
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Infections in Accident and emergency Philip G. Murphy Consultant in Medical Microbiology, AMNCH Clinical Professor, TCD Tel. ext. 3919 philip.murphy@amnch.ie
Lecture objectives • Integrate Microbiology knowledge to A&E Doctor • Consider factors unique to A & E dept Vs GP • Emergency infections • Trauma infection eg tetanus • Systematic approach to A & E infection • Ix and Dx clinical Vs empirical • Others: tourist fever, bites, sharps, infection control • Is an antibiotic indicated ?
Unique factors in A&E • Concerned patient/parent ?? Need admission • Interface of community and hospital • Gatekeeper of all inpatient admission • Under-resourced in IRL • Over usage Vs GP. • GP 2nd opinion • Triage
Emergency Infections • Meningitis (Pen access) • Bacteraemia / septicaemia • Endocarditis • Osteomyelitis • Otherwise minor infection in Immunsuppressed eg varicella septicaemia Fresh splinter haemorrhage Meningococcal petechiae purpura & DIC (bleeding NG)
Meningitis • Bacterial: N. Men ABC, pneumococcus, Hib, E coli, List. • Viral: Enterovirus group, Herpes • Hx: prodrome, contact • Dx: Meningism, fever, rash • Ix: CT. CSF and blood C&S, PCR • Rx: Ceftriaxone, pen • Px: ?who, rifampicin 600mg bd 2 days • Public Health
What is Shock? • A physiologic state characterised by • Decrease in tissue perfusion • Inadequate oxygen delivery • Delivery isn’t keeping up with demand • May be bacterial: LPS, toxin Gram negative – E. coli Gram Positive - Staphylococcus aureus
What is SIRS? The systemic inflammatory response syndrome is systemic level of acute inflammation, that may or may not be due to infection, and is generally manifested as a combination of vital sign abnormalities including fever or hypothermia, tachycardia, and tachypnoea.
Risk Factors for SIRS/Sepsis • Extremes of age • Indwelling lines/catheters • Immunocompromised states • Malnutrition • Alcoholism • Malignancy • Diabetes • Cirrhosis • Male sex • Genetic predisposition?
The Continuum of Sepsis SIRS Sepsis Severe Sepsis Septic Shock • Systemic Inflammatory Response Syndrome • SIRS criteria-must have 2 or more of the following: • Temp < 36 ° C or > 38 ° C • HR > 90 • RR > 20 or PCO2 < 4.3 • WBC < 4 or > 12 or immature bands > 10% Bone et al. Chest 1992;101:1644
The Continuum of Sepsis SIRS Sepsis Severe Sepsis Septic Shock • Sepsis = • Suspected or confirmed infection • 2 or more SIRS criteria Bone et al. Chest 1992;101:1644; Balk, RA
The Continuum of Sepsis SIRS Sepsis Severe Sepsis Septic Shock • Sepsis plus Organ Dysfunction • Elevated Creatinine • Elevated INR. Hyperbili • Altered Mental Status • Elevated Lactate >4 • Hypotension that responds to fluid Bone et al. Chest 1992;101:1644
The Continuum of Sepsis SIRS Sepsis Severe Sepsis Septic Shock • Severe Sepsis and Hypotension (SBP < 90mmHg) • Hypotension that does NOT respond to fluid (30 mls/kg bolus) Bone et al. Chest 1992;101:1644
Septic Shock • Combination • Distributive • Cardiogenic • Hypovolaemic • Most common form of Shock • On a continuum from SIRS to Septic Shock
Why so Important? Mortality of Severe Sepsis Severe Sepsis‡ AIDS* Breast Cancer§ AMI† †National Center for Health Statistics, 2001.§American Cancer Society, 2001. *American Heart Association. 2000.‡Angus DC et al. Crit Care Med. 2001 .
Shock: antibiotic Mx • Bactericidal not bacteriostatic • Rapid kill without LPS release eg gentamicin • Broad cover and de-escalate later in recovery • Beta lactam + aminoglycoside • +/- ano2 (metronidazole) • +/- glycopeptide (vancomycin) • System review focus
Why so important? • Overall mortality from SIRS/sepsis is approx. 20%. • Mortality is roughly linearly related to the number of organ failures, with each additional organ failure raising the mortality rate by 15%. • Hypothermia is one of the worst prognostic signs. Patients presenting with SIRS and hypothermia have an overall mortality of ~80%.
Factors influencing prescribing Choice Organism susceptibility Concurrent therapy Drug rep pressure Patient pressure Policies Prophylaxis Drug familiarity: Dosage / cost Toxicity / kinetics Bioavailability Best guess susceptibility Patient immune state Nature of infection Patient physiology Allergy history Breast feeding Pregnancy Age Compliance Social/work issues
Trauma infection • Wound management • Compound or closed • Dirty e.g., Tetanus • cSSI e.g.,Cellulitis
Cellulitis • 90% Haemolytic Streptococci • 10% Staphylococci • Culture if skin broken • Rx Penicillin + Flucloxacillin • Increase dose until erythema controlled • Monitor CRP • 2nd line Clindamycin • Beware necrotising fasciitis
Tetanus preventionClostridium tetanus toxin = neuromuscular toxin S+S: muscle spasm near wound, later generalised, lockjawRx: Ig, vaccine, antibiotic • Type of woundClean (Low Risk) Tetanus Prone (High Risk) • Clean incised wound Any wound or burn > 6 hours old • Superficial graze Any wound with one or more of the following: • Scald Contact with soil, manure, compost Puncture type wound Infected wound Compound fracture Wound containing foreign bodies Large amount of devitalised tissue Animal or human bite
Risk assessment of wounds for use of tetanus immunoglobulin (TIG) Age Immunisation statusClean woundTetanus prone wound <4 y <3 doses or unknown DTaP/IPV+/-Hib TIG, DTaP/IPV +/- Hib 3 or more doses Nil Nil Consider TIG >4 to 9y <3 doses or unknown DTaP/IPV TIG plus DTaP/IPV 3 doses only, >5 years since last dose DTaP/IPV DTaP/IPVConsider TIG 3 or more doses, <5 years since last tetanus toxoid Nil Nil Consider TIG 4 or more doses, >5 years since last dose Nil DTaP/IPV, consider TIG >10 y <3 doses or unknown Td TIG plus Td/IPV 3 or more doses >10 years since last dose Td Td, consider TIG 3 or more doses, <10 years since last dose Nil Consider TIG www.immunisation.ie
? AntibioticUse a system approach • URT • LRT 70% of antibiotic prescriptions • SST • GUT- STD • CVS Shock emergency • CNS meningitis emergency • GIT diarrhoea • Common viral: HS, VZ • Others: tropical parasites, Toxoplasmosis etc • Post-op hospital & minor ops.
Primary care • 80% of all antibiotics • 80% respiratory tract indications • >50% still probably unnecessary • Cough probably the commonest acute single reason for consulting (130 per 1000 patients per year)
LRTI Etiologic determinants for pneumonia Host characteristics Age State of health Immunocompetence Environmental exposure Geographic location Community acquired vs nosocomial Closed population settings (daycare centers, military camps, nursing homes) Unusual exposures (eg, animals) Pathogen characteristics Virulence Inoculum size Multi-lobar Pneumococcal Bronchial pneumococcal Apical TB Diffuse alveolar Influenzae
Community Acquired Pneumonia • Epidemiology: • Incidence 3/1000 • Mortality 2-30% • <1% for those not requiring hospitalisation • fewest cases in 18-24 yr group • probably highest incidence in <5 and >65 yrs • mortality disproportionately high in >65 yrs
Community Acquired Pneumonia Mortality # in 1000s
Community Acquired Pneumonia • Risk Factors for pneumonia • age • alcoholism • smoking • asthma • immunosuppression • institutionalisation • COPD • PVD • dementia ID Clinics 1998;12:723. Am J Med 1994;96:313
Community Acquired Pneumonia • Laboratory Tests: • CXR • FBC with differential • U+E • glucose • LFTs • Sputum culture • Blood culture • oxygen saturation • Urinary antigen: pneumococcus or Legionella
Community Acquired Pneumonia Diagnostic Evaluation • CXR • usually needed to establish diagnosis • prognostic indicator • rule out other disorders • may help in etiological diagnosis • Only 3% of outpatients and 28% of ED patients with suggestive signs and symptoms actually have pneumonia J Chr Dis 1984;37:215-25
CURB-65:Confusion (8 or less on AMT)Urea > 7Resp Rate > 30BP (< 90/60)Age > 65Score: 0-1 low risk (non severe - discharge) 2 increased risk (consider admission) 3 high risk (severe – admit)Also useful: Sats <92% or PaO2 <8 kPa Bilateral disease Age >50 Co-morbidity BTS CAP guidelines: Thorax 2004
Microbial aetiology Conventional • Haemophilus influenzae (3-10%) • Streptococcus pneumoniae (20-60%) • Moraxella catarrhalis • Mycoplasma pneumoniae (1-6%) • Chlamydia pneumoniae (4-6%) • Chlamydia psittaci • Legionella pneumoniae (2-8%) • Coxiella burnetti • Viral (2-13%) • 40-60% No cause identified • 2-5% 2 or more causes identified Atypical
Hospital CAP Antibiotic strategy • 1st line: Augmentin +/- macrolide (clarithromycin) Moxifloxacin if pen allergic • 2nd line: 3rd gen ceph +/- quinolone eg., ceftriaxone +/- ciprofloxacin
Tourist Fever • Think global - act local • Avian influenzae (H5N1) • SARS • Haemorrhagic fevers (Lassa, Ebola) • Legionella • Typhoid • Others
Avian flu Acute onset of fever ( ≥ 38°C) with S & S of an acute respiratory infection. AND At least one of the following exposures < 7 days prior to onset of symptoms: Contact with poultry or wild birds Reside in or have visited an area of a country where influenza A/H5N1 is currently suspected or confirmed as reported in the HPSC web-site http://www.ndsc.ie/hpsc/A-Z/Respiratory/AvianInfluenza/AffectedCountries/ Having been in close contact with sick or dead domestic poultry and/or wild birds in an affected area; or having been in a home or farm where sick or dead domestic poultry have been reported in the previous six weeks in an affected area; Human Contact: Having been in close contact (<1 metre) with a person reported as a probable or confirmed case of influenza A/H5N1; Laboratory Contact: Having worked in a laboratory where there is potential exposure to influenza A/H5N1. http://www.ndsc.ie/hpsc/A-Z/Respiratory/AvianInfluenza/Guidance/File,2199,en.pdf Inform Public Health infection control and Occupation Health. Health care workers caring for cases of suspected A (H5N1) should be considered for prophylaxis with oseltamivir (Tamiflu).
+ case definition Infection Control/ Isolation and Reporting • Strict hand hygiene. • Patient to be put into a side room in the ED immediately. • Staff to wear respirator mask – minimum standard FFP2, gown/plastic apron, gloves. • Patient to wear surgical mask. • Inform and consult with Infection Control prior to moving or transferring patient (e.g. X ray).
Blood borne virus exposure(eg needle stick) • Risk assessment of wound & injury • Wound toilet • Hep B – vaccine if non immune +/- HBIg if source positive • Hep C - Monitor blood, LFT’s • HIV – assess for PEP
Animal bites • Dogs 80% • Cats 10% • Humans 5% • Others 5% • Basic wound Mx do not close (2o closure) • Antibiotics if deep Rx Augmentin • Rabies Rx Vaccine x 5 (+ Ig if high risk)
Infection Control • Irish A&E departments inadequate • isolation, toilet and washing facilities • Attempt to isolate and cohort: diarrhoea,TB., Norovirus
Lecture self assessmentGive examples for each • How does A&E differ from 10 and 2o care • Emergency infections • Management of infected trauma • Other examples