Pneumonia Flashcards
What is the definition of pneumonia?
Pneumonia is an infection of the pulmonary parenchyma from the alveoli
What are the differential diagnoses of respiratory infections?
Sinusitis Pharyngitis Bronchitis COPD exacerbation Pneumonia
What is the typical presentation of pneumonia?
Systemic symptoms:
Acute onset, fever, tachypnea
Respiratory symptoms:
Cough, purulent sputum, lung consolidation
Chest X-ray:
Infiltrate (Lobar = typical, patchy/diffuse = atypical)
What are the three settings that pneumonia cases are categorized by?
Community acquired (acute or sub-acute) Healthcare Associated (eg, nursing homes) Hospital/Ventilator acquired (nosocomial)
What are the common signs and organisms of typical CA-pneumonia?
- Purulent sputum
- Gram’s stain may show organism (60%)
- Lobar infiltrate on CXR
Pneumococcus
H. influenza
Moraxella catarrhalis
S. aureus (CA-MRSA)
What are the common signs and organisms of atypical CA-pneumonia?
- Cough prominent, ± purulent sputum
- Gram’s stain with PMNs, but few organisms
- Patchy or diffuse infiltrate on CXR
Mycoplasma pneumonia
Chlamoydophila pneumoniae
Legionella pneumophila
Influenza; RSV, adenovirus
What are common fungal causes of pneumonia?
Histoplasmosis, Blastomycosis, Coccidiomycosis, Apergillus) (not Candida- lower virulence; “less bad bug”)
What bacteria are commonly associated with aspiration pneumonia?
Anaerobes (only with aspiration)
What are some non-infective causes of pneumonia?
Reactive (chemicals, drugs, Farmers' lung); Radiation; Autoimmune; infiltrative cancer; congestive heart failure
What is the definition of HCAP and what are some common bacterial agents?
Nursing home;
Hospital, dialysis, Chemo in 30 days,
hosp. in 180d
- Less S. pneumo,
- atypicals (x/c influenza) (Mycoplasma pneumonia,
Chlamoydophila pneumonia, Legionella pneumophila, RSV, adenovirus), ± H. flu - Some GNR and Staphylococcus aureus
What is the definition of HAP/VAP and what are some common bacterial agents?
Hospital-acquired (HAP) or ventilator-associated (VAP)
- Little pneumococcus and few atypicals
- GNR (inc. Ps. aeruginosa) and Staphylococcus aureus prominent
- Increased Multi-drug resistance (MDR) (e.g., GNR, MRSA)
What are the symptoms, risk groups, and anti-microbial susceptibility of pneumococcal pneumonia?
Classic presentation of community-acquired pneumonia (acute, local, alveolar, sputum)
Risk groups:
- Elderly - Alcoholism - Liver disease - Hematologic malignancy - Immunosuppression (esp. HIV-1) - Smoking
Antimicrobial susceptibility:
- Increasing incidence of decreased penicillin susceptibility (5-25%) (may not affect response to therapy of pneumonia)
- Penicillin-resistance associated with multiple drug resistance
- Other streptococci - Group A β streptococci (acute, very ill, pleural effusions)
- Not Enterococcus (less bad bug; limited virulence)
What are the symptoms, risk groups, and anti-microbial susceptibility of H. influenza pneumonia?
Symptoms:
cough, purulent sputum, fever, but NO PULMONARY INFILTRATE on CXR
- 2nd most common of “typical” pneumonia
- Invasive adult disease often caused by non-encapsulated strains (50%) (non-type b)
Antimicrobial susceptibility:
- 36% ampicillin-resistant (b-lactamase)
What are the symptoms, risk groups, and anti-microbial susceptibility of S. aureus pneumonia?
Symptoms:
- Increased severity; necrotizing pneumonia, shock, abscess, empyema, respiratory failure
- Virulent organisms with significant tissue injury;
Risk groups:
- Often in children, Native Americans; gay men; crowding (jail, barracks); HIV; homeless youth
- May follow and complicate influenza
Therapy:
IV – Linezolid, Vancomycin,; Not daptomycin (binds surfactant and inactivated)
Oral – TMP-SMX, mino/doxycycline, + clindamycin
- Classically health-care-associated MRSA are more MDR organisms
What are three causes of atypical pneumonia?
Mycoplasma pneumonia:
- “walking pneumonia;” CXR worse than pt.
Chlamydia pneumoniae (TWAR)
Legionella pneumophila:
- Regional; Uncommon in Colorado - Suspect if immunocompromised,
- Sputum culture - low yield (@ 10%); urine antigen is best test (> 70% if type 1)
What are some pulmonary and infectious complications of CAP?
Pulmonary complications: Effusion Respiratory failure Cavitation Pneumothorax Pulmonary embolism
Infectious complications: Nosocomial Empyema Arthritis Abscess Endocarditis
What tests are appropriate for patients hospitalized with CAP?
- CXR
- O2 SAT (if ↓, ABG)
- CBC
- Cr, LFT
- Blood culture
- Gram’s stain, culture of sputum, ± AFB and culture, tests for Legionella (culture, DFA test, or urinary antigen assay), and measurement of mycoplasma IgM
- Pleural-fluid analysis*
- HIV (if 15-54 y.o.)
What are the parameters of the CURB-65 criteria?
Age at or above 65 years Confusion BUN above 19 mg/dl Respiratory Rate at or above 30/min BP - hypotension (Less than 90 or diastolic less than 60)
Score of 2 = hospitalization
Score of 3+ = ICU
What drugs should be prescribed for pneumonia in a previously healthy patient with no antibiotic use in the past three months?
Macrolides (Azithromycin, Clarithromycin, Erythromycin)
and
Doxycycline
What drugs should be prescribed for pneumonia in a patient with significant co-morbidities or antibiotic use in the past three months?
Fluoroquinolone (Moxifloxacin, gemifloxacin, levofloxacin)
or
B-Lactam plus a Macrolide
What drugs should be prescribed for pneumonia in an in-patient (non-ICU)?
Fluoroquinolone (moxifloxacin, gemifloxacin, levofloxacin)
or
B-Lactam plus a macrolide
What drugs should be prescribed for pneumonia in a patient in the ICU?
B-Lactam (cefotaxime, ceftriaxone, or ampicillin-sulbactam)
plus either
azithromycin or fluoroquinolone
What drugs should be prescribed for pneumonia in a patient where pseudomonas is suspected?
Anti-Pseudomonas B-lactam (Pip-Taz, Cefepime, imipenem, meropenem)
+/- amino glycoside and azythromycin
or
+/- amino glycoside and anti-pneumococcal fluoroquinolone
What drugs should be prescribed for pneumonia in a patient where MRSA is a concern?
Add vancomycin or linezolid to therapy
Four methods to prevent community acquired pneumonia?
Limit - Aspiration, Smoking / Environmental smoke exposure (esp. cooking in home)
Vaccine – S. pneumoniae; H. influenza b; Influenza
Passive Immunity – RSV
Antimicrobial – Influenza (oseltamavir)
What are the two pneumococcal vaccines?
1) 23-valent polysaccharide for adults;
2) 13-valent conjugate (Prevnar) for children
What is a significant limitation of the adult pneumococcal vaccine?
It does not prevent pneumonia. Only effective against bacteremia.
How are influenza vaccines indicated for?
Indicated for patients with high-risk conditions, in
chronic care facilities, healthy ≥ 65 years; almost everyone
- Medical care personnel – protect yourself, protect patients
Asymptomatic people can transmit to others
Decreased illness - 60-80% in children/young adults; 30% institutionalized elderly
Decreased serious illness and death: About 70% in elde
What are the advantages of the childhood pneumococcal vaccine?
- Reduces colonization
- Reduces bacteremia >90%
- Reduces bacterial pneumonia
- ≤ 37% in African children
- Some reduction in serious otitis and meningitis
