Pneumonia lecture,Describe the common pathogenesis and pathogens of pneumonia
Discuss diagnosis and initial management of community acquired pneumonia (CAP)
Understand features of the Pneumonia PORT Severity Index
Discuss the IDSA/ATS guidelines and recommendations for final antibiotic choice
Understand issues in basic management for pneumonia in children, nursing home patients, and immunocompromised patients.
2. Objectives
• Describe the common pathogenesis and pathogens o
f pneumonia
• Discuss diagnosis and initial management of commu
nity acquired pneumonia (CAP)
• Understand features of the Pneumonia PORT Severit
y Index
• Discuss the IDSA/ATS guidelines and recommendatio
ns for final antibiotic choice
• Understand issues in basic management for pneumo
nia in children, nursing home patients, and immunoc
ompromised patients.
3. Epidemiology
• Unclear! Few population-based statistics on the cond
ition alone
• CDC combines PNA with influenza for morbidity & m
ortality data
– PNA & influenza = 7th leading causes of death in the US (2
001)
– Age-adjusted death rate = 21.8 per 100,000
– Mortality rate: 1-5% out-Pt, 12% In-Pt, 40% ICU
– Death rates increase with comorbidity and age
– Affects race and sex equally
4.
5.
6. Community Acquired Pneumonia
• Infection of the lung parenchyma in a person
who is not hospitalized or living in a long-ter
m care facility for ≥ 2 weeks
• 5.6 million cases annually in the U.S.
• Estimated total annual cost of health care = $8
.4 billion
• Most common pathogen = S. pneumo (60-70%
of CAP cases)
7. “Nosocomial” Pneumonia
• Hospital-acquired pneumonia (HAP)
– Occurs 48 hours or more after admission, which w
as not incubating at the time of admission
• Ventilator-associated pneumonia (VAP)
– Arises more than 48-72 hours after endotracheal i
ntubation
8. “Nosocomial” Pneumonia
• Healthcare-associated pneumonia (HCAP)
– Patients who were hospitalized in an acute care hospital fo
r two or more days within 90 days of the infection; resided
in a nursing home or LTC facility; received recent IV abx, ch
emotherapy, or wound care within the past 30 days of the
current infection; or attended a hospital or hemodialysis cli
nic
• Guidelines for the Management of Adults with HAP, V
AP, and HCAP. American Thoracic Society, 2005
9. Pathogenesis
• Inhalation, aspiration and hematogenous spre
ad are the 3 main mechanisms by which bacte
ria reaches the lungs
• Primary inhalation: when organisms bypass n
ormal respiratory defense mechanisms or whe
n the Pt inhales aerobic GN organisms that col
onize the upper respiratory tract or respiratory
support equipment
10. Pathogenesis
• Aspiration: occurs when the Pt aspirates colon
ized upper respiratory tract secretions
– Stomach: reservoir of GNR that can ascend, coloni
zing the respiratory tract.
• Hematogenous: originate from a distant sourc
e and reach the lungs via the blood stream.
11. Pathogens
• CAP usually caused by a single organism
• Even with extensive diagnostic testing, most in
vestigators cannot identify a specific etiology f
or CAP in ≥ 50% of patients.
• In those identified, S. pneumo is causative pat
hogen 60-70% of the time
12. Streptococcus pneumonia
• Most common cause of CAP
• Gram positive diplococci
• “Typical” symptoms (e.g. malaise, shaking chill
s, fever, rusty sputum, pleuritic chest pain, cou
gh)
• Lobar infiltrate on CXR
• Suppressed host
• 25% bacteremic
13. Atypical Pneumonia
• #2 cause (especially in younger population)
• Commonly associated with milder Sx’s: subacute ons
et, non-productive cough, no focal infiltrate on CXR
• Mycoplasma: younger Pts, extra-pulm Sx’s (anemia,
rashes), headache, sore throat
• Chlamydia: year round, URI Sx, sore throat
• Legionella: higher mortality rate, water-borne outbre
aks, hyponatremia, diarrhea
14. Viral Pneumonia
• More common cause in children
– RSV, influenza, parainfluenza
• Influenza most important viral cause in adults,
especially during winter months
• Post-influenza pneumonia (secondary bacteria
l infection)
– S. pneumo, Staph aureus
17. Guidelines
• American Thoracic Society
– Guidelines for the Management of Adults with CA (2001)
• Infectious Diseases Society of America
– Update of Practice Guidelines for the Management of CAP
in Immunocompetent adults (2003)
• ATS and IDSA joint effort
– IDSA/ATS Consensus Guidelines on the Management of CA
P in Adults (March 2007)
19. Signs and Symptoms
• Fever or hypothermia
• Cough with or without sputum, hemoptysis
• Pleuritic chest pain
• Myalgia, malaise, fatigue
• GI symptoms
• Dyspnea
• Rales, rhonchi, wheezing
• Egophony, bronchial breath sounds
• Dullness to percussion
• Atypical Sx’s in older patients
20. Clinical Diagnosis: CXR
• Demonstrable infiltrate by CXR or other imagi
ng technique
– Establish Dx and presence of complications (pleur
al effusion, multilobar disease)
– May not be possible in some outpatient settings
– CXR: classically thought of as the gold standard
21. Infiltrate Patterns
Pattern Possible Diagnosis
Lobar S. pneumo, Kleb, H. flu,
GN
Patchy Atypicals, viral, Legionell
a
Interstitial Viral, PCP, Legionella
Cavitary Anaerobes, Kleb, TB, S.
aureus, fungi
Large effusion Staph, anaerobes, Kleb
22. Clinical Diagnosis: Recommended testi
ng
• Outpatient: CXR, sputum Cx and Gram stain n
ot required
• Inpatient: CXR, Pox or ABG, chemistry, CBC, tw
o sets of blood Cx’s
– If suspect drug-resistant pathogen or organism no
t covered by usual empiric abx, obtain sputum Cx
and Gram stain.
– Severe CAP: Legionella urinary antigen, consider b
ronchoscopy to identify pathogen
23. Clinical Diagnosis
• Assess overall clinical picture
• PORT Pneumonia Severity Index (PSI)
– Aids in assessment of mortality risk and dispositio
n
– Age, gender, NH, co-morbidities, physical exam lab
/radiographic findings
24. Severity assessment
• There are currently two sets of criteria:
– the Pneumonia Severity Index (PSI), a prognostic
model used to identify patients at low risk of dying
; and
– the CURB-65 criteria, a severity-of-illness score.
25. PSI
• points are given for 20 variables, including age
, coexisting illness, and abnormal physical and
laboratory findings.
• On the basis of the resulting score, patients ar
e assigned to one of five classes with the follo
wing mortality rates: class 1, 0.1%; class 2, 0.6
%; class 3, 2.8%; class 4, 8.2%; and class 5, 29.
2%.
26. • Clinical trials have demonstrated that routine
use of the PSI results in lower admission rates
for class 1 and class 2 patients. Patients in clas
ses 4 and 5 should be admitted to the hospital
, while those in class 3 should ideally be admit
ted to an observation unit until a further decis
ion can be made.
27. CURB-65
• 5 variables:
– confusion (C);
– urea >7 mmol/L (U);
– respiratory rate 30/min (R);
– blood pressure, systolic 90 mmHg or diastolic 60
mmHg (B); and
– age 65 years (65).
28. • Patients with a score of 0, among whom the 3
0-day mortality rate is 1.5%, can be treated ou
tside the hospital.
• With a score of 2, the 30-day mortality rate is
9.2%, and patients should be admitted to the
hospital.
• Among patients with scores of 3, mortality rat
es are 22% overall; these patients may require
admission to an ICU.
29. IDSA: Outpt Management in Previously
Healthy Pt
• Organisms: S. pneumo, Mycoplasma, viral, Chlamydia
pneumo, H. flu
• Recommended abx:
– Advanced generation macrolide (azithro or clarithro) or do
xycycline
• If abx within past 3 months:
– Respiratory quinolone (moxi-, levo-, gemi-), OR
– Advanced macrolide + amoxicillin, OR
– Advanced macrolide + amoxicillin-clavulanate
30. IDSA: Outpt Management in Pt with co
morbidities
• Comorbidities: cardiopulmonary dz or immunocompr
omised state
• Organisms: S. pneumo, viral, H. flu, aerobic GN rods,
S. aureus
• Recommended Abx:
– Respiratory quinolone, OR advanced macrolide
• Recent Abx:
– Respiratory quinolone OR
– Advanced macrolide + beta-lactam
31. IDSA: Inpt Management-Medical Ward
• Organisms: all of the above plus polymicrobial infecti
ons (+/- anaerobes), Legionella
• Recommended Parenteral Abx:
– Respiratory fluoroquinolone, OR
– Advanced macrolide plus a beta-lactam
• Recent Abx:
– As above. Regimen selected will depend on nature of rece
nt antibiotic therapy.
32. IDSA: Inpt Management-Severe/ICU
• One of two major criteria:
– Mechanical ventilation
– Septic shock, OR
• Two of three minor criteria:
– SBP≤90mmHg,
– Multilobar disease
– PaO2/FIO2 ratio < 250
• Organisms: S. pneumo, Legionella, GN, Mycopl
asma, viral, ?Pseudomonas
33. IDSA: Inpt Management: Severe/ICU
• No risk for Pseudomonas
– IV beta-lactam plus either
• IV macrolide, OR IV fluoroquinolone
• Risk for Pseudomonas
– Double therapy: selected IV antipseudomonal beta-lactam
(cefepine, imipenem, meropenem, piperacillin/tazobactam
), plus
• IV antipseudomonal quinolone
-OR-
– Triple therapy: selected IV antipseudomonal beta-lactam pl
us
IV aminoglycoside plus either
IV macrolide, OR IV antipseudomonal quinolone
34. Switch to Oral Therapy
• Four criteria:
– Improvement in cough and dyspnea
– Afebrile on two occasions 8 h apart
– WBC decreasing
– Functioning GI tract with adequate oral intake
• If overall clinical picture is otherwise favorable
, can can switch to oral therapy while still febri
le.
35. Management of Poor Responders
• Consider non-infectious illnesses
• Consider less common pathogens
• Consider serologic testing
• Broaden antibiotic therapy
• Consider bronchoscopy
36. Prevention
• Smoking cessation
• Vaccination per ACIP recommendations
– Influenza
• Inactivated vaccine for people >50 yo, those at risk for i
nfluenza compolications, household contacts of high-ris
k persons and healthcare workers
• Intranasal live, attenuated vaccine: 5-49yo without chro
nic underlying dz
– Pneumococcal
• Immunocompetent ≥ 65 yo, chronic illness and immuno
compromised ≤ 64 yo
37. Pneumonia in Children: Dx
• Symptoms
– Infants: non-specific manifestations
• Fever, poor feeding, irritability, vomiting, diarrhea, URI Sx, cough, r
espiratory distress
– Older children: more specific
• Fever, cough, chest pain, tachypnea, tachycardia, grunting, nasal fl
aring, retracting. Cyanosis usually very late.
• Signs/Physical exam
– RR > 60 for all ages
– Hypoxia
– Rales, wheezes, crackles, coarse breath sounds
38. Pneumonia in Children: Pathogens
• 0-4 wks: GBS, GN enterics, Listeria
• 4-12 wks: C. trachomatis, GBS, GN enterics, Lis
teria, viral (RSV/parainfluenza), B. pertussis
• 3 mos-4 yrs: Viral, S. pneumo, H. influenza, M.
catarrhalis, Grp A Strep, Mycoplasma
• > 5yrs: Mycoplasma (5-15yrs), C. pneumo, S. p
neumo, viral
39. Pneumonia in the Elderly
• Prevention important
• Presentation can be subtle
• Antibiotic choice in CAP is same as other adults
• Healthcare associated pneumonia
– Consider S. aureus (skin wounds) and GN bacteria (aspirati
on)
• Pneumonia in Older Residents of Long-term Care Facilities. AFP 20
04; 70: 1495-1500.
40. Pneumonia in Immunocompromised P
ts
• Smokers, alcoholics, bedridden, immuno-compromis
ed, elderly
• Common still common
– S. pneumo
– Mycoplasma
• Pneumocystis Carinii Pneumonia
– P. jirovecii
– Fever, dyspnea, non-prod cough (triad 50%), insidious onse
t in AIDS, acute in other immunocompromised Pts
– CXR: bilateral interstitial infiltrates
– Steroids for hypoxia
– TMP-SMZ still first line
41.
42. Lung abscess
• Localised area of suppuration and tissue necr
osis.
• Causes:
– Aspiration of infected oropharyngeal contents /
vomitus.
– Poor oral hygiene and sepsis.
• Risk of aspiration:
– Loss of consciousness (alcoholic stupor, anaesthe
sia, epilepsy).
– Oesophageal pathology (carcinoma, congenital at
resia / fistula).
43. • Obstruction of bronchus
– carcinoma,
– foreign body.
• Complication of pneumonia
– virulent organisms esp. Klebsiella, Staph.
• Bronchiectasis.
• Septic embolism (infective endocarditis on right-
sided heart valves) or septisaemia.
• Penetrating trauma e.g. stab wound.
• Direct spread of sepsis from other organs (e.g. a
moebic liver abscess).
44. Complications
• Rupture into pleural space ⇒ empyema or br
oncho-pleural fistula (⇒ pyopneumothorax).
• Rupture into pericardium ⇒ pericarditis.
• Septisaemia ⇒ sepsis in other organs e.g. ost
eomyelitis, brain abscess.
• Erosion of blood vessels ⇒ haemoptysis.
• Organisation ⇒ fibrosis.
46. IDSA/ATS 2007 Guideline
• Hospital Admission Decision
– CURB-65 criteria (confusion, uremia, RR, low BP, age 65 yrs
or greater) or PSI can be used to ID candidates for outpt m
anagement
• Diagnostic Testing
– Acknowledges the low yield and infrequent positive impact
on clinical care
– Outpt testing for etiologic Dx remain optional
– Inpt testing for etiologic Dx recommended for specific indic
ations
• Antimicrobial therapy: essentially unchanged
47. Summary
• Use overall clinical presentation to guide thera
py
• The admission decision is an “art of medicine”
decision
• Use risk factors and guidelines to assist with cli
nical judgement