Pneumonia

1. Pneumonia Dr Andrew Dodgson Consultant Microbiologist

2. Terminology • Histological/Radiological • Lobar vs bronchopneumonia • Lobar vs. interstitial • Microbiological • Bacterial, viral, fungal • Clinical/ Microbiological • Atypical vs. typical • Clinical/epidemiological • Community acquired vs. nosocomial • All have clinical relevance though none is absolute

4. Terminology • Histological/Radiological • Lobar vs bronchopneumonia • Lobar vs. interstitial • Microbiological • Bacterial, viral, fungal • Clinical/ Microbiological • Atypical vs. typical • Clinical/epidemiological • Community acquired vs. nosocomial • All have clinical relevance though none is absolute

5. Importance • “the most widespread and fatal of all acute diseases, pneumonia is now Captain of the Men of Death” Osler, 1901 (Principles and Practice of Medicine, 4th Ed.) • Pneumonia is 6th leading cause of death in US • Leading infectious cause of death • 5 million deaths/year worldwide • High mortality rate • Outpatient: 5% • Inpatient: 12% • ITU: 40%

6. Clinical Presentation • Cough (productive vs. non-productive) • Fever • Dyspnoea • Fatigue • Headache • Nausea, vomiting, diarrhoea • Myalgia

7. Predisposing factors • Age • COPD • Diabetes • Heart failure • Immunocompromised states • Alcoholism • Smoking • Travel/occupational/recreational exposure

8. Physical signs • Tachycardia • Tachypnoea • Hypotension • Creps • Bronchial breathing • Fever

9. Physical signs • Physical exam has a sensitivity of 47-60% and specificity of 50-75% • However in pt’s with creps, fever, cough and tachycardia the possibility of pneumonia increases from 18 to 42% • Also, pt’s with none of RR>20, HR>100 and temp>37.8ºC have a <1% chance of having pneumonia

10. Investigation • Chest X-ray • FBC • CRP • U&E’s • ABG’s • Sputum culture • Blood culture (+ve in 1-16% of pt’s requiring admission) • Serology/PCR/antigen

11. Severity assessment • CURB-65 • Confusion • Urea >7mmol/L • Respiratory rate >30 • Blood pressure diastolic <60mmHg or systolic <90 • ≥65 years old • 0-1-may be suitable for outpatient Rx • 2 Hospital Rx, consider other features too (e.g. PaO2) • ≥3 Severe disease

12. 0 5 10 15 20 25 30 Percentage of Cases PNEUMONIA AETIOLOGY S pneumoniae C pneumoniae* Viral M pneumoniae Legionella spp H influenzae G- Enterobacteria C psittaci Coxiella burnetii S aureus M catarrhalis Other Data from 26 prospective studies (5961 adults) from 10 countries. *Data from 6 studies. Woodhead MA. Chest. 1998;113:183S-187S.

13. Community Acquired S. pneumoniae H. influenzae Atypicals S. aureus Kleb. pneumoniae Hospital Acquired Gram negatives E.g. E.coli, Klebsiella, Pseudomonas S. aureus Atypicals infrequent S. pneumoniae rare Aetiology

14. S. pneumoniae Gram +ve diplococci Almost all S to penicillins, cephalosporins (R more common is southern Europe and S. Africa) Most S to erythromycin H. influenzae G –ve cocco-bacilli S to amoxycillin 25% produce B-lactamase, thus Amoxy R. S to Co-Amoxyclav, ceph’s, Ciprofloxacin R Eryth Pathogens

16. S. pneumoniae Gram +ve diplococci Almost all S to penicillins, cephalosporins (R more common is southern Europe and S. Africa) Most S to erythromycin H. influenzae G –ve cocco-bacilli S to amoxycillin 25% produce B-lactamase, thus Amoxy R. S to Co-Amoxyclav, ceph’s, Ciprofloxacin R Eryth Pathogens

17. Pathogens • S. aureus • Seen classically after flu • Severe necrotising pneumonia in young adults seen in PVL (toxin) producing strains-emerging pathogen • Rx flucloxacillin, eryth. • Vancomycin, linezolid for MRSA

18. Atypical pneumonia • Caused by organisms that will not grow under routine culture conditions • Non-productive cough • Negative culture • Clinical signs often do not match severity of clinical (and radiological) presentation • Legionella, Mycoplasma, C. psittacci, C. pneumoniae, C. burnetii, viruses (esp. influenza)

19. Aspiration pneumonia • Occurs in patients with abnormal gag reflex (altered consciousness, CVA…) • Combination of chemical (acid) injury, bronchial obstruction and bacterial infection. • Bacteria involved will reflect oropharyngeal flora-anaerobes and Streps & haemophilus (community) or gram neg’s (nosocomial) • Rx often broad spectrum B-lactam e.s. co-amoxyclav or pipperacillin/tazobactam +/- metronidazole

20. Sputum culture • Interpretation • Macroscopic appearance • Mucoid or purulent? • Presence of leukocytes • Organism isolated • Pure culture or mixed? • Amount? • Likely pathogen given the situation? • What’s happening to the patient?

23. Diagnosing Atypical Pneumonia • Clinically • Laboratory: • Culture-not likely to be useful • Serology-detects antibody response • Usually take time • Requires demonstration of a single high level or 4-fold rise (after 10-14 days) • Immunocompromised patients? • Antigen detection • Good strategy but only available for Legionella • PCR • Detects DNA/RNA of organism • Potentially excellent strategy • Only available in reference centres currently • Will likely be method of choice in future

24. Diagnosis of LegionellaAm J Med, 2001; 110:41-48 Sputum culture Selective media Results in 2 -7 days 10% sensitivity vs serology 61% sensitivity vs DFA Better if endotracheal/BAL Urine antigen Results in 1 -6 hours Can take ~ 5 days to turn pos Can remain pos for up to 6 wk Inexpensive Serogroup 1 specific 70-80% sensitivity 100% specificity (serogrp 1) Direct Fluorescent Antibody Stain (DFA) of sputum Need large numbers of orgs. Sensitivity approx 50% 60 - 70% specificity for particular serotypes Serology - ELISA Acute & convalescent samples needed 4-12 weeks for AB response Single titre of 1:256 = disease 20% have no AB response PCR Fast – sensitivity of ~ 70% Can be used for sputum Currently research use only

26. Treatment Need to consider: • Setting • Community or hospital • Severity • CURB-65 score

27. Treatment-Community acquired CURB65 0-1 • Amoxycillin 500-1g TDS CURB65 2 • Amoxycillin AND Clarithromycin 500mg BD CURB65 ≥3 • Co-amoxyclav 1.2g TDS AND Clarithromycin 500mg BD-Both given IV

28. Treatment-Nosocomial Occurring ≥48 hrs post admission Usually • Co-amoxyclav However if severe or recently on ITU or recent Abx • Piperacillin/tazobactam

29. Treatment-Specific organisms S. pneumoniae • Benzylpenicillin or amoxycillin S. aureus • Flucloxacillin Legionella • Clarithromycin (or a quinolone e.g. Cipro) Psitacosis or Q fever • Doxycycline Mycoplasma • Clarithromycin C. pneumoniae • Clarithromycin

30. Other aetiologies • TB • Viral • Fungal • Pneumocystis

31. Questions