Pneumonia Flashcards
pneumonia
General
Common, inflammatory disease affecting the alveoli of the lungs (parenchyma)
Most often caused by infection - bacteria, virus, fungi or parasite
Epidemiology:
Accounts for more than 800,000 hospitalizations in the United States annually
Most common cause of death due to infection in the United States
More common in winter and in colder climates
Higher incidence and mortality rate in advanced age
pneumonia
classifications of community acquired and Nosocomial
Community-acquired pneumonia (CAP):
Pneumonia acquired outside of the hospital setting or within 48 hours of admission to the hospital
Nosocomial pneumonia:
Pneumonia acquired in the hospital settings
Encompasses hospital-acquired pneumonia(HAP) andventilator-associated pneumonia(VAP)
HAP refers to pneumonia acquired ≥48 hours after hospital admission
VAP refers to pneumonia acquired ≥48 hours after endotracheal intubation or within 48 hours of extubation
pneumonia
Aspiration pneumonia
Pneumonia in the setting of increased risk of aspiration such as poor gag/cough reflex or a critically ill status
pneumonia
atypical pneumonia and clinically characterized by
Type of community-acquired pneumonia caused by atypical organisms
(Mycoplasma pneumoniae,Chlamydia pneumoniae, and respiratory viruses)
and is clinically characterized by milder symptoms with no lobar infiltrates on x-ray
pneumonia
Patho
Lobar vs interstitial pneumonia
Exposure to a pathogen via inhalation, aspiration, contiguous or hematological mechanism
Proliferation of the microbe in the lower airways and alveoli
Local response of the alveolar epithelial cells release cytokines into the surrounding tissue to recruit neutrophils to the site of inflammation
Inflammatory response varies depending on the type of invading pathogen
-
Lobar pneumonia:
Accumulation of neutrophils and plasma exudate from capillaries into alveoli specific to a lung lobe
Clinically: productive cough, hypoxemia, dyspnea, consolidation on CXR -
Interstitial pneumonia:
Accumulation of infiltrates in the alveolar walls
Clinically: dry cough, hypoxemia, dyspnea
Systemic cytokines release as a response to the invading microbe leads to a disruption in the hypothalamic thermoregulation → fever, chills/rigors
Community-acquired pneumonia (CAP)
general
Pathogens
Transmission: from person to person by droplets in the air
Pneumococci bacteria are common inhabitants of the human respiratory tract
Common pathogens:
Bacterial
Typical: Streptococcus pneumoniae, Haemophilus influenzae, Chlamydia pneumoniae, Group A streptococci, Moraxella catarrhalis, anaerobes, and aerobic gram-negative bacteria; Community-acquired methicillin-resistantS. aureus(CA-MRSA)…increasing incidence since 2000
Atypical: Legionella, Mycoplasma pneumoniae, Chlamydia pneumoniae, and Chlamydia psittaci
Viral
Rhinoviruses, Coronaviruses, Respiratory syncytial virus, Adenoviruses, Influenza viruses, Metapneumovirus, Parainfluenza viruses
Fungal
Histoplasma capsulatum (histoplasmosis), Coccidioides immitis (coccidioidomycosis)
Pneumocystis jirovecci → immunosuppressed and HIV patients
(only 60% of cases do we know the pathogen)
CAP
RF
Age > 65 years and < 2 years
Immunosuppression
Chronic conditions (especially cardiopulmonary diseases)
Reduced gag/cough reflex
Smoking
Living in crowded conditions
Institutionalized (nursing homes, group homes)
Alcoholism
Long term corticosteroid use
CAP
Clin Man
Cough:
Productive (mucoid, purulent, or blood-tinged sputum)
Nonproductive (mostly with atypical pneumonias)
Gross hemoptysis suggests CA-MRSA
Dyspnea:
Mild to severe
Often exertional
Pleuritic chest pain
Nonspecific symptoms:
Fever, palpitations, chills, rigors, night sweats, fatigue, nausea, vomiting, headache, myalgia, arthralgia
Pneumonia in the elderly may present with confusion
Pneumonia
Physical exam findings
Physical examination:
Increased respiratory rate and use of accessory muscles
Increased tactile fremitus and dullness to percussion: consolidation
Auscultation: crackles or bronchial sounds
Pneumonia
Dx
imaging and labs
Suspicion based on clinical presentation
Imaging:
CXR: gold standard for diagnosis
CT scan of the chest
Obtained when there is high clinical suspicion and the CXR does not reveal an infiltrate
Labs: only for pts being admitted not outpatient
Moderate to severe pneumonia or likely infection with MRSA orPseudomonas aeruginosa
CBC with differential
BMP
ABGs
Blood cultures: hypoxia and respiratory acidosis
12% of all patients hospitalized with pneumonia have bacteremia (S. pneumoniae)
Sputum culture
Urine testing for Legionellaantigen and pneumococcal antigen (severely ill)
pneumonia
Procalcitonin (PCT)
she does not endorse it
Procalcitonin (PCT)
Newer biomarker for the early detection of systemic bacterial infections
Data
Positive correlation between high serum levels of PCT and patients with positive findings for bacterial infection and sepsis
Levels increased 6-12 hours followinginitial bacterial infections
Levels increased steadily in the 2-4 hours following the onset of sepsis
Serum levels of PCT did not elevate in viral infections
Serum levels of PCT would decrease following the administration of appropriate antibiotic therapies
Procalcitonin is NOT endorsed as a way to determine who gets antibiotics
American Journal of Respiratory and Critical Care Medicine
Recommend that empiric antibiotic therapy be initiated in adults with clinically suspected and radiographically confirmed CAP regardless of initial serum procalcitonin level
Pneumonia
CXR
Multi lobar, cavitating
Findings generally cannot distinguish one type of infection from another
Multilobar infiltrates
S. pneumoniae or Legionella infection
Interstitial pneumonia
Increased interstitial markings and subpleural reticular opacities that increase from the apex to the bases of the lungs
Viral or mycoplasmal etiology
Cavitating pneumonia
S. aureus, fungal, or mycobacterial etiology
RUL and RML pneumonia (multi lobar)
Fevers, productive cough and hemoptysis. Recent intravenous drug use. No history of travel or exposure to tuberculosis.
Right middle lobe consolidation with an associated cavitating lesion.
Community acquired methicillin resistant staphylococcus aureus pneumonia
Pneumonia Severity index (PSI)
First and most validated risk prediction rule for pneumonia
Estimates mortality risk and helps to guide decisions regarding hospitalization
Based on a combination of patient demographics, comorbidities, physical examination findings, and laboratory and imaging studies
should use in decision making but probably not for test
Pneumonia Severity index (PSI)
should use in decision making but probably not for test
Pneumonia
CURB-65
Alternate assessment tool for pneumonia
Easier to use in the clinical setting because it requires fewer inputs than the PSI
pneumonia
Severe CAP – ICU admission
Intensive Care Unit admission is required for patients who:
At least 1 of the following:
Hypotension (SBP ≤90 mm Hg) that is unresponsive to volume resuscitation → requiring vasopressors
Respiratory failure requiring mechanical ventilation
3 or more of the following:
Respirations ≥ 30/min,
PaO2/FiO2≤ 250
Multilobar pneumonia
Confusion
Blood urea nitrogen ≥ 20 mg/dL
WBC < 4,000 cells/µL
Platelet < 100,000/µL
Hypothermia
Hypotension requiring aggressive fluid management
pneumonia
Tx
Normal and with comorbidities
outpatient
80% of cases are treated as outpatients
Initial antibiotic treatment for outpatients with CAP:
No comorbidities or risk factors for MRSA orP. aeruginosa:
Amoxicillin OR Doxycycline
With comorbidities (congestive heart disease, chronic lung disease, malignancy, cerebrovascular disease, renal disease, liver disease):
- Amoxicillin/clavulanate (or cephalosporin) AND macrolide (or doxycycline) OR
- Respiratory fluoroquinolone (levofloxacin, moxifloxacin, gemifloxacin)
pneumonia
Tx
Severe/non severe/MRSA/p.aeruginosa
| inpatient
20% of patients are treated as inpatients
Initial antibiotic treatment for inpatients with CAP:
Antibiotics should be initiated ≤ 4 hours after presentation
Nonsevere (non-ICU):
β-lactam and macrolide OR
Respiratory fluoroquinolone
Severe (ICU):
β-lactam and macrolide (preferred) OR
β-lactam and respiratory fluoroquinolone
Empiric coverage for MRSA includes vancomycin or linezolid
Empiric coverage forP. aeruginosa includes piperacillin-tazobactam, cefepime, ceftazidime, aztreonam, meropenem, or imipenem
pneumonia
duration of Abx therapy
At least 5 days; longer duration for more severe infection
Based on improvement of vital signs, mentation, ability to eat, and the patient’s overall clinical condition
If a patient fails to improve in 72 hours, another cause, antibiotic resistance or development of complications like empyema should be suspected
Pneumonia
Adjunctive measures in the treatment of CAP:
IV hydration
Oxygen therapy for hypoxemia
Vasopressors for shock
Mechanical ventilation for respiratory failure
Antipyretics
Thromboembolic prophylaxis
Smoking cessation counseling
pneumonia
Prognosis
Short-term mortality is related to the severity of illness
Death due to pneumonia, progression to sepsis, or exacerbation of a coexisting condition
Mortality varies by the pathogen involved:
S. pneumoniae: most common cause of death
Gram-negative bacteria
CA-MRSA
Mortality is higher in patients who do not respond to initial empiric antibiotics
pneumonia
prevention
just know there are vaccines available. Dont memorize.
Some forms of community-acquired pneumonia are preventable with vaccination
Twopneumococcal vaccinesavailable:
- 13-valent pneumococcal conjugate vaccine - PCV13 (Prevnar 13)
Recommended for:
Children 2 months to 2 years
Adults ≥ 19 years with certain comorbidities
Adults ≥ 65 years - 23-valent pneumococcal polysaccharide vaccine - PPSV23 (Pneumovax 23)
Recommended for:
All adults ≥ 65 years
Any patient ≥ 2 years who has risk factors for pneumococcal infections (underlying heart, lung, or immune system disorders)
Patients that smoke
CDC recommends PCV13 for all infants as a series of 4 doses
Give 1 dose at 2 months, 4 months, 6 months, and 12 through 15 months
dont memorize.
Hospital Acquired pneumonia
general
Develops at least 48 hours after hospital admission in patients not receiving mechanical ventilation
Etiology:
-Microaspiration of bacteria that colonize the oropharynx and upper airways in seriously ill patients*
- Bacteremia or inhalation of contaminated aerosols (particles containing Legionella, Aspergillus, influenza virus) are less common
hospital acquired Pneumonia
pathogens
Vary significantly among institutions and can vary within institutions over short periods (month to month)
Most significant pathogens:
Enteric gram-negative bacilli → Pseudomonas aeruginosa, Enterobacter species, Klebsiella pneumoniae, Escherichia coli
Gram-positive cocci → MSSA and MRSA
MSSA, Streptococcus pneumoniae, and Haemophilus influenzae are most commonly implicated when pneumonia develops within 4-7 days of hospitalization
Hospital acquired pnuemonia
General S/Sx
Generally, the same as CAP:
Malaise
Fever
Chills/rigors
Cough
Dyspnea
Chest pain
hospital acquired pneumonia
Dx
Imaging:
CXR
CT scan of the chest
Gram stain and sputum culture
Help to direct empiric therapy
Pleural fluid culture
Reliably identifies both pneumonia and the responsible organism
hosp. acquired pneumonia
Tx
Antibiotics that are chosen empirically based on:
Local sensitivity patterns
Patient risk factor for antibiotic-resistant pathogens
Initial treatment with broad-spectrum antibiotics
With results of cultures and antibiotic susceptibility testing antibiotics are changed to the narrowest regimen possible (single agent)
Appropriate clinical response is expected within 48–72 hours
pneumocystis pneumonia (PCP)
general
Causative agent:
Pneumocystis jiroveciiis a yeast-like fungus
Classically affects patients with AIDS (AIDS-defining illness)
CD4 ≤ 200 cells/μL → Trimethoprim-sulfamethoxazole (TMP-SMX) preventatively
Spread through airborne transmission
pneumocystis pneumonia (PCP)
Clin Man
Dry or productive cough?
Clinical presentation: insidious onset
Fever
Chills
Dry cough
Chest pain
Shortness of breath
pneumocystis pneumonia
Dx
Increased β-D-glucan (component of the fungal cell wall) level
Diffuse, bilateral infiltrates on chest imaging
Definitive diagnosis made with microscopy of induced sputum or specimens from bronchoalveolar lavage (BAL)
pneumocystis pneumonia
Tx
1st line: trimethoprim-sulfamethoxazole (TMP-SMX)
Moderate disease: Oral route is preferred, consider adding corticosteroids
Severe disease: Use IV TMP-SMX plus corticosteroids
