Table of contents
- 1. Introduction
- 2. Community Acquired Pneumonia
- 2.1. Microbiology
- 2.2. Symptoms
- 2.3. Unusual Pathogens
- 2.4. Classification
- 2.5. Investigations
- 2.6. Management
- 2.6.1. Admit or Not Admit
- 2.6.2. Admission to ICU decision criteria:
- 2.6.3. Antimicrobial Therapy
- 2.7. Complications
- 3. Notes on Specific Organisms
- 3.1. S. pneumoniae
- 3.2. Haemophilus influenzae
- 3.3. Staphylococcus aureus
- 3.4. Legionella pneumophila
- 3.5. Atypical pneumonias
- 3.5.1. Mycoplasma pneumoniae
- 3.5.2. Chlamydia pneumoniae
- 3.5.3. Viruses:
- 4. Hospital Acquired Pneumonia / Ventilator Associated
- 4.1. Empiric Therapy:
- 5. Ventilator Associated Pneumonia
- 6. Tuberculosis
- 7. Atypical Mycobacteria
- 8. Fungal Pneumonias
- 8.1. Histoplasmosis
- 8.2. Coccidiomycosis
- 9. Quick Summary
.
Introduction
- Classified as:
- Community Acquired Pneumonia (CAP)
- Acute pneumonia in those not recently hospitalized, and not living in facilities (i.e. nursing home).
- Risk factors: Age (>65), DMII, CV disease, COPD, chronic bronchitis, alcoholism, neuro diseases.
- Smokers: high risk of invasive pneumococcal infections even without structural lung disease.
- Community Acquired Pneumonia (CAP)
- Generally caused by microaspiration of organisms that colonize oral pharynx (usually during sleep).
- Except Legionella - due to aerosolized contaminated water particles.
- Aspiration pneumonia
- larve volume aspiration of gastric contents --> chemical pneumonitis --> bacterial infection.
- Other important points:
- Use of guidelines to direct therapy decreases mortality in hospitalized patients with CAP
Community Acquired Pneumonia
Microbiology
- Community Acquired Pneumonia Organisms
- Streptococcus pneumoniae
(often bactermic pneumonia) - Haemophilus influenzae
- Moraxella catarrhalis
- Klebsiella pneumoniae (less common)
- (alcoholism)
- HIGHLY resistance strains possible
- Streptococcus pneumoniae
- So-called "Atypical" Organisms
- Mycoplasma
- Chlamydophila (prev Chlamydia)
- Intracellular anaerobe
- Both Mycoplasma and Clamydophila termed "walking pneumonia" generally in outpatients (mild).
- Legionella
- In pts with severe CAP, history of travel.
- More common in summer, often in epidemics when common-source reservoir aerosolizes bacteria (i.e. water systems, air conditioning units, such as at a hotel or cruise ship)
- Ass'd with hyponatremia, AST/ALT elevation, GI symptoms, bradycardia.
- Has urinary antigen test (only picks up Legionella pneumophila type 1)
- Helpful if positive, but negative test doesn't exclude dx.
- Other pathogens: (rare)
- Staph aureus
- Less common cause of CAP.
- Risk Factors: classically following influenza, cavitary pneumonia, no risk factors for aspiration, IVDU, recent history of CA-MRSA skin infection.
- High mortality rate, cause prolongued hospitalization.
- often ventilator associated pn.
- Gram negatives (enteric)
- uncommon, unless lung disease or alcoholism. (reduced gag reflex). Usually hospitals and nursing homes.
- Pseudomonas
- Often underlying structural lung disease
- Risk Factors: Bronchiectasis, Cystic Fibrosis, frequent COPD Exacerbations, long term steroid therapy.
- Often underlying structural lung disease
- Anaerobes
- Often aspiration pneumonias.
- Viral
- influenza, parainfluenza, respiratory syncitial virus (RSV), adenovirus (adenovirus Type 14 - severe)
- Staph aureus
- Nosocomial Infections:
- Gram negatives (>50%)
- Staph aureus (13-40%) (wound infections, burns, intubated, head trauma)
- Anaerobes (5%)
Risk Factors: (Intubation, >70yrs, reduced LOC, malnutrition, metabolic acidosis)
- Aspiration Infections:
- (aware of pulmonary burn aspiration of gastric contents, obstructing objects)
- (foul-smelling spututm, lung abscesses and empyema)
- (OFTEN MIXED ORGANISMS)
- Mixed Gram negative enteric aerobic rods
- Anaerobes
- Staph aureus
- Rare
- Actinomycosis (poor oral hygeine, anaerobic)
- Nocardiosis (inhalation of soil particles)
Symptoms
- Acute Cough - purulent sputum.
- (S. pneumon is rusty colored, red current jelly color is Klebsiella etc..)
- Fever, chills, pleuritic chest pain, dyspnea
- Rigor - classically one teeth-chattering chill is Strep. pneumo.
- Shortness of breath
- Elderly
- Often non-specific presentation, present with confusion, exacerbation of chronic cardiopulmonary disease.
- Tachypnea is the most sensitive finding in edlerly.
- Rule out risk factors for HAP (Healthcare Associated Pneumonia)
- Antibiotic therapy or hospitalization in preceeding 90 days.
- Epidemiologic history for unusual pathogens.
Unusual Pathogens
- Aspiration - Gram negative enteric pathogens, organ anaerobes.
- Cough >2w with post-tussive vomiting: Bordetella pertussus.
- Cavitary infiltrates - Community MRSA, oral anaerobes, fungal pathogens, TB
- Alcoholism - Klebsiella, Staph aureus, oral anaerobes.
- COPD/Smoking - Gram Negatives, Haemophilus, Pseudomonas, Legionella, S. aureus, Moraxella, clamodophila.
- Bat/Bird Droppings Exposure - Histoplasma capsillatum (if right geographic locale)
- Bird Expsoure - Clamydophila psittaci
- Rabbits - Tularemia
- Farm Animal / Pregnant Cats - Coxiella burnetii (Q-fever)
- Rodents Excreta - Hantavirus (recent)
- HIV Infection - Common organisms + PJP, cryptococcus, histoplasma, aspergillosis, pseudomonas, mycobacterium.
- Hotel/Cruise Ship - Legionella
- SW United States - Coccidioidomycosis species or Hantavirus. (California, desert)
- SE or E Africa - Burkholdaria pseudomallei
- Influenza - Primary influenza, secondary bacterial pneumonia (S. pneumo, S. aureus, H.influ).
- IVDU - S. aureus, TB, pneumococcus.
- Endobronchial obstruction - anaerobes, pneumococcus, H.influenzae.
- Bronchiectasis, Cystic Fibrosis - Pseudomonas or Burkholdaria cepacia
- Bioterrorism - Anthrax, Plague, Tularemia.
Classification
- Classified as:
- Typical Pneumonia
- Rapid onset, severe symptoms, productive cough, dense CXR consolidation.
- Atypical Pneumonia
- Slower onset, less severe symptoms, less severe cough, minimal sputum, CXR (patchy/interstitial pattern)
- Community Acquired (<14d in hospital)
- Hospital Acquired (>14d)
- Typical Pneumonia
- Can sometimes narrow down to organism by symptoms and radiologic findings.
- Chest Xray findings:
- 1. Lobar Pneumonia
- Distinct anatomic segment of the lung. Respects anatomic boundaries (no proteases/hyaloronidases to break down tissue).
- S. pneumoniae, H. influenzae, Legionella
- 2. Bronchopneumonia
- 3. Intersitial pneumonia
- Lung interstitium inflamed: fine diffuse grandular infiltrate.
- Influenza, CMV, Pneumocystis jirovecii, Miliary TB (micronodular infiltrates).
- (Can look like CHF)
- 4. Lung abscess
- Tissue necrosis, cavities with inflammatory fluid
- Do CT
- Anaerobics and S.aureus.
- 5. Nodular Lesions
- Yeasts: (cryptococcus) Moulds (Histoplasmosis, coccidiomycosis) - nodular
- Do CT
- "Cannonball lesions" from hematogenous spread of endocarditis.
- 1. Lobar Pneumonia
Investigations
- Diagnosis:
- Clinical findings are often not sufficient to diagnose pneumonia
- CXR is mandatory, but initial normal CXR does not exclude if has focal resp physical exam findings + symptoms.
- Repeat CXR in 24-48hrs may show airspace disease.
- Workup:
- CBC + differential, O2 sat, arterial gasses (pH <7.35 = bad, or O2 < 60mmHg = bad)
- BUN > 10.7 mmol/L (kidney hypoperfusion or dehydration)
- Serum Na < 130 (increased ADH from depleted volume).
- Glucose > 13.9 (bad prognostic factor)
- Consider: Blood cultures, sputum gram stain + culture, pneumococcal + legionella urine antigen testing (all required for ICU)
- Blood cultures x2
- Draw before first dose of abx, esp in ICU, on hospitalized pts it's unclear. I.e. is a quality medicare indicator in all hospitalized admissions, but most guidelines for ICU only.
- Positive in 5-14% of hospitalized CAP pts. --> obtain before abx (quality care indicator for medicare)
- Initially studies indicated lack of benefit of cultures in non-severe CAP, but now optional.
- See table on UpToDate (recreated below)
- Sputum Gram Stain and Culture
- Controversial: Guidelines by Infections Disease Society of America and American Thoracic Society:
- Optional for outpatients.
- In hospitalized pts (not in ICU) recommended for: (optional in the rest)
- Outpatient therapy ineffective
- Cavitary infiltrates
- Alcoholism
- Chronic Liver Disease
- Functional or Anatomic Asplenia
- Severe Obstructive or Structural Lung Disease
- Leukopenia
- Lots of pharynx contamination (need to cough deeply to bring up sputum).. may represent colonization. (Check for squamous cells (>10 is poor sample) and PMNs + bronchial epithelial cells (good sample))
- Sputum for : Gram stain, cultures, sensitivity, PCR
- PMNs --> bacterial, Mononuclear cells --> Mycoplasma, Chlamydia, viral
- Difficult to culture Legionella, mycoplasma, chlamydia, Pneumocystis jirovecii, likely need PCR
- Can also do urinary antigens.
- Controversial: Guidelines by Infections Disease Society of America and American Thoracic Society:
- Bronchoalveolar lavage - useful for PJP
- Legionella urine antigen Indicated for recent travel pts, but often done by specialists on high risk patients.
- (only picks up Legionella pneumophila type 1). 70-90% Sn, 99% Sp.
- Pneumococcal urine atigen: 70% Sn, 96% SP, rapid test.
- NOTE: Severe CAP requiring ICU admission should have blood cultures, Legionella, and pneumococcus urinary antigens, and sputum culture (expectorated or endotrachial aspirate).
-
Indication Blood
Culture
Sputum
Culture
Legionella
UAT
Pneumococcal
UAT
Other ICU Admission X X X X - Endotracheal Aspirate or Bronch or BAL Failure of Outpt Abx Therapy X X X Cavitary Infiltrates X X - Fungal + TB cultures Leukipenia X X Alcohol Abuse X X X X Chronic Severe Liver Disease X X Severe Obstructive/Structural Lung Disease X Asplenia (anatomic or functional) X X Recent Travel (within past 2 weeks) X - Complex (see "Unusual Pathogens") Positive Legionella UAT Result X --- Positive Pneumococcal UAT Result X X --- Pleural Effusion X X X X - Thoracentesis and pleural fluid cultures
Management
-
Admit or Not Admit
- Outpatient management is preferrable, several scoring systems help guide hospitalization need.
- CURB65 is very common (because it's easy compared to PSI)
-
Pneumonia Severity Index (PSI)
- Complicated calcuation (20 different variables), use online calculator.
- Assigns to 5 mortality risk groups (I - V)
- Groups 1-2 => Outpatient Management (Low Mortality Risk Groups)
- Group 3 => Brief hospitalization for observation
- Groups 4-5 => Require hospitalization
- PORT score is also around, but not as common.
- CURB65 and PSI scoring systems most popular.
- Studies show that both are effective for predicting mortality.
- Negative predictive value is greater than positive.
- Also predict the time to clinical stability.
- However, they are part of the decision. Pts with poor social supports and underlying chronic disease etc.. require admission that aren't in scoring systems.
- CAP considered severe if requires early ICU care.
- Patients admitted to ICU have lower mortality than those transferred to the ICU. Hence early ICU admission reduces mortality for severe CAP.
- 50% of ICU deaths due to CAP occurs in patients who were initially admitted to the medical ward
-
Admission to ICU decision criteria:
- Proposed to the Infectious Diseases Society of America (IDSA) and American Thoracic Society proposed guidelines for ICU admission (major + minor criteria)
-
Major Criteria Minor Criteria - Need for mechanical vent and
vasopressor support
- Clinical
- Confusion (new-onset disorientation to person, place, or time)
- Hypothermia (core temperature <36.0 °C [96.8 °F])
- Respiration rate ≥30/min
- Hypotension necessitating aggressive fluid resuscitation
- Multilobar pulmonary infiltrates
- Laboratory
- Arterial PO2/FIO2 ratio ≤250 or requiring NIPP
- Leukopenia (<4000 cells/µL [4.0 × 109/L])
- Thrombocytopenia (<100,000 /µL [10 × 109/L])
- Blood urea nitrogen >20 mg/dL (7.1 mmol/L)
- Major Criteria => Admit to ICU
- ≥ 3 Mintor Criteria => Admit to ICU
This has not undergone extensive validation, but recent investigation has shown that the negative predictive value of the severe CAP minor criteria is greater than 90%.
- Need for mechanical vent and
Antimicrobial Therapy
- Studies as of 2014: Initial mgmt: no difference between empric therapy and pathogen-directed therapy except in ICU.
- Pathogen directed therapy may have fewer adverse effects.
- Confirming etiologic dx helpful if fail to respond to abx.
- Key Point: Risk factors for macrolide resistant pneumococcus:
- Age > 65
- Recent B-lactam use in <3mo
- Medical comorbidities (COPD, DMII, Cancer, CKD, Asplenia anatomic or functional)
- Immunocompromise
- Alcoholism
- Child in daycare
- Empiric Therapy:
- Start therapy within 4-6 hours of diagnosis (relates to mortality)
- Choice depends on outpatient vs. inpatient vs. ICU + risk factors. (see chart)
- General Principles of Therapy: (Rationale for above guidelines)
- Azithromycin covers typical and atypical organisms. However, widespread macrolide use for respiratory infections in 80's and 90's led to pneumococcus resistance to macrolides (~30% depending on locale).
- Hence nowadays macrolide monotherapy only used in healthy outpatient populations who can tolerate incomplete coverage - if does not respond, they can be treated as a "non-responder" with a better regimen.
- (MAJORITY OF CASES) The patient has comorbidities (cannot afford not covering resistant pneumococcus) or high risk of resistant pneumococcus (Daycare, recent <3mo B-lactam use), or severe infection (requiring admission or ICU), must cover resistant pneumoccocus with:
- respiratory fluoroquinolone (gemifloxacin, levofloxacin, moxifloxacin) (NOT ciprofloxacin as it does not cover aerobic G+'s). These agents also cover atypical organisms.
OR - macrolide (i.e. azithromycin) for atypical organisms, but combine with an agent that covers macrolide-resistant pneumococcus (i.e. ceftriaxone, ceftazidime, carbepenems, amox-clav etc.. many choices!)
- respiratory fluoroquinolone (gemifloxacin, levofloxacin, moxifloxacin) (NOT ciprofloxacin as it does not cover aerobic G+'s). These agents also cover atypical organisms.
- If risk factors for pseudomonas (i.e. chronic structural lung disease, steroids, -- see chart)
- Cover with antipseudomonal agent in addition to previous regimens.
- US guidelines suggest double-covering pseudomonas (due to high level pseudomonas resistance in US), hence most regimens require combinations of:
- Anti-pseudomonal B-lactam
- Ciprofloxacin, levofloxacin
- NOTE: Common misconception of cipro being more potent than levo. This is a test-tube phenomenon, in vivo either one can be used based on published guidelines)
- Aminoglycosides
- NOTE: For bacteremic pneumococcus, studies indicate that combination of B-lactam and macrolide is better. Either due to co-infection with an atypical or anti-inflammatory effect of macrolides.
- Azithromycin covers typical and atypical organisms. However, widespread macrolide use for respiratory infections in 80's and 90's led to pneumococcus resistance to macrolides (~30% depending on locale).
- Aspiration Outpatient
- (Cover mixed G- rods, anaerobes and S. aureus)
- Penicillin or clindamycin (should cover most oral flora).. Clindamycin better for abscess.
- Aspiration Inpatient
- (Cover resistant mixed G- rods, anaerobes and S. aureus)
- Use 3rd gen cephalosporin or resp fluoroquinolone
- COMBINE WITH metronidazole
- OR use pip-tazo or ticarcillin-clavulanate.
- Duration:
- 72 hours after afebrile is a good marker.
- If necrosis of lung (S. aureus or Klebsiella, anaerobes), may need up to 2 weeks.
- Switch to oral when improving (keep same class!!!)
- Large Pleural Effusions
- Defined "Large" if occupies > 1/2 hemithorax or fluid level >1cm on lateral decubitus.
- Needs thoracetesis + blood, sputum cultures + Legionella Urine Antigen
- Monitor Response to treatment:
- Temperature
- Resp rate
- PaO2 / O2 sat
- Symptoms
- WBC
- CANNOT Monitor via CXR.. changes can persist for weeks.
-
NEVER USE CHEST XRAY TO MONITOR RESPONSE TO TREATMENT
(can take weeks to resolve in absence of infection)
- Discharge
- Criteria to change from IV to Oral Therapy: (And Discharge, no need to ruotinely observe on oral therapy)
- Temperature ≤ 37.8
- HR ≤ 100
- RR < 24/min
- sBP ≥ 90
- O2sat ≥ 90%
- PO2 ≥ 60 on room air
- Tolerating Oral Intake
- Normal Mental Status
- Total Duration of Therapy:
- 7 days (including time in hospital)
- Long Duration for:
- Those taking long to be clinically stable
- Cavitary pneumonia
- S. aureus or Pseudomonas pneumonia
- NOTE: Pneumococcal bacteremia: do not usually require longer therapy
- REQUIRED: Pneumococcal + influenza vaccine (Quality of Care)
- Criteria to change from IV to Oral Therapy: (And Discharge, no need to ruotinely observe on oral therapy)
Complications
- If not improvement consider:
- BOOP
- Vasulitis
- PE
- Resistant Pathogen
- Parapnemonic effusion or empyema (esp if initially improve then relapse).
- 1/3 develop effusion.
- Thoracentesis if ≥50% of hemithorax (large pleural effusion) or fail to respond clinically.
- (If stable, improving, but small-to-moderate effusion, can just observe)
- Follow-up
- Chest imaging not indicated in most patients.
- F/U CXR - consider to document clearance and r/o malignancy (9.2% had pulmonary malignancy)
- 6-8 weeks for smokers, and >40yo.
- Counsel smokers
- F/U office visit 10-14 days post-therapy.
Notes on Specific Organisms
-
S. pneumoniae
- On Microscopy:
- "Lancet-shaped diplococci"
- Many subtypes
- "Lancet-shaped diplococci"
- Thick outer capsule blocks phagocytosis (Type 3 is the thickest capsule)
- Immunoglobulins/opsonins important in phagocytosis
- Does not cross anatomic barriers (cannot break down tissue?). Host inflammation causes damage.
- High risk people:
- Risk is higher in opsonins deficiencies
- Hypogammaglobulinemia
- Complement deficiency
- HIV
- Splenic dysfunction
- Chronic diseases:
- Cirrhosis
- Alcoholism
- Nephrotic syndrome
- CHF
- COPD
- Risk is higher in opsonins deficiencies
- Classically big "rigor/chill", and Sputum can be rusty in color
- Lots of penicillin resistance (25%-35%)
- Treatment:
- Use penicillin/ampicillin for pen-sensitive strains.
- High dose parenteral penicillin, a 3rd gen cephalosporin or oral amoxicillin used for intermediate-sensitivity strains (except meningitis!)
- Resp fluoroquinolone (gatiflox, moxiflox, levoflox) work for high-level pen resistant strains, but do not work for meningitis.
- Use vancomycin for meningits
- GIVE PNEUMOCOCCAL VACCINE! (23 valent)
- Especially to:
- >65yo
- Chronic disease
- Asplenic
- Immunocompromised
- Alcoholic
- Especially to:
- On Microscopy:
-
Haemophilus influenzae
- Small gram-negative coccobacilli
- CXR:
- Often Lobar, but sometimes patchy pneumonia.
- Group B and non-typable cause CAP
- non-typable more common in elderly and smokers with COPD.
- Treatment:
- IV: Ceftriaxone, cefotaxime
- Oral: amox-clav.
- TMP-SMX, new macrolides (azithro, clarithro), fluoroquinolones, and extended cephalosporins also work.
-
Staphylococcus aureus
- Clasically: follows influenza infection
- Often used as a marker of influenza epidemic.
- More common in HIV and IV drug use.
- CXR: bronchopneumonia, lung abscesses
- MSSA: high dose nafcillin or oxacillin
- MRSA: vancomycin with blood monitoring 15-20 ug/mL (can also do linezolid, but expensive!!)
- Clasically: follows influenza infection
-
Legionella pneumophila
- Gram-negative bacilli
- Found in standing water and soil
- Inhallation of contaminated water droplets (shower heads, cooling towers), or excavations - soil particles.
- Sometimes nosocomial: use of unsterilized tap water.
- Typical pneumonia features, however:
- 1. small amounts of sputum
- 2. confusion/headache.
- 3. GI symptoms
- 4. Hyponatremia
- Need special culture medium (buffered charcoal) with suppresive abx.
- PCR and urinary antigen also used.
- Treatment: Use azithromycin or fluoroquinolones.
- In transplant: use fluoroquinolones (azithromycin interacts with immunosuppressive meds metabolism).
- Mortality 16-50%
-
Atypical pneumonias
- Treat with a macrolide or tetracycline
-
Mycoplasma pneumoniae
- Most frequent pneumonia in young <40yo ppl.
- Most common in late summer and early fall.
- Sx:
- Sore throat, bullous myringitis (5%).
- Tracheobronchitis: Hacking cough, worse at night, lasting several weeks.
- CXR: patchy infiltrates.
- No rapid dx test.
- Treatment
- Macrolide (azithromycin x5days)
- Tetracycline
-
Chlamydia pneumoniae
- Taiwan acute respiratory agent.
- 5-15% of pneumonias.
- Presents similar to mycoplasma with same CXR.
- Treatment:
- Tetraycycline
- Macrolides, fluoroquinolones are also effective.
-
Viruses:
- Influenza A + B, parainfluenza virus, RSV (kids, elderly), adenovirus
- Rapid tests exist for influenza.
- Treatment:
- Influenza A: amantadine, rimantadine.
- Influenza A, B, + others?: neuramidase inhibitor
- Treat within 48hr onset.
Hospital Acquired Pneumonia / Ventilator Associated
- HAP:
- Pneumonia that occurs ≥48hrs after hospital admission and not incubating at time of admission
- 2nd leading cause of hospital infection (after catheter UTI)
- Mechanical Ventilation is the strongest risk factor for HAP (incidence 6-20 fold grader in ventilator patients), re-intubation is an additional risk factor for HAP/VAP.
The 2005 American Thoracic Society/Infectious Diseases Society of America (ATS/IDSA) guidelines on the management of adults with hospital-acquired, ventilator-associated, and healthcare-associated pneumonia used the following definitions [2]:
- Hospital-acquired (or nosocomial) pneumonia (HAP)
- ≥ 48 hours or more after admission and did not appear to be incubating at the time of admission.
- Ventilator-associated pneumonia (VAP)
- Type of HAP --> 48 to 72 hours after endotracheal intubation.
- Healthcare-associated pneumonia (HCAP)
- Nonhospitalized patient with extensive healthcare contact, as defined by one or more of the following:
- Intravenous therapy, wound care, or intravenous chemotherapy within the prior 30 days
- Residence in a nursing home or other long-term care facility
- Hospitalization in an acute care hospital for two or more days within the prior 90 days
- Attendance at a hospital or hemodialysis clinic within the prior 30 days
- Nonhospitalized patient with extensive healthcare contact, as defined by one or more of the following:
Empiric Therapy:
- Step 1: Risk Factors for MDR?
-
Use of antibiotics within the preceding 90 days
-
Current hospitalization of ≥5 days
-
High frequency of antibiotic resistance in the community or in the specific hospital unit
-
Immunosuppressive disease and/or therapy
-
(Severe septic shock)
-
HCAP risk factor
-
-
If Risk Factors for MDR: (ONE of)
-
Antipseudomonal cephalosporin (ceftazidime 2g q8h, cefepime 2g q8h)
-
Antipseudomonal carbepenem (meropenem 1g q8h, imipenem 500mg-1g q6h)
-
Pip-tazo 4.5g q6h
-
If penicillin allergic --> (if mild, rash etc..) can trial cephalosporin or aztreonam (even less cross-reactivity)
-
If penicillin anaphylaxis --> consult allergy specialist
-
-
Add-on therapies
-
Ciprofloxacin
-
Levofloxacin
-
Gentamycin
-
Tobramycin
-
-
PLUS ONE of the following (if MRSA is suspected, there are MRSA risk factors, or there is a high incidence of MRSA locally):
-
Linezolid
-
Vancomycin (15-20mg/kg + dose interval by renal function)
-
Telavancin
-
Source; IDSA Guidelines / UpToDate.com
Ventilator Associated Pneumonia
- Subset of Hospital Acquired Pneumonia
- Pneumonia that develops >48-72hrs after mechanical ventilation started.
- 50% of VAP occur in first 4 days of intubation
- Classic Symptoms (only present in 30-40% of VAP)
- CXR pulmonary infiltrate
- Fever
- Leukocytosis
- Purulent Sputum Production
- Organisms:
- Diagnosis:
-
Treatment:
-
Depends on what patient is colonzied with.
-
Risk of colonization with Staph aureus and gram-negative rods:
-
Unlikely Colonized Likely Colonized All of:
- Admitted < 5d ago
- Admitted from home
- No other admissions in past 3mo
- Not dialysis patient
One of:
Admitted > 5d ago
Admitted from nursing home
Other admissions in past 3mo
A dialysis patient
Empiric Antibiotics
- Ceftriaxone or Quinolone
Empiric Antibiotics
- Piperacillin-tazobactam or
- Carbapenem or
- Ceftazidime or cefepime
PLUS
- Vancomycin or linezolid
(to cover MRSA and vanco-resistant MRSA/VRE)
AND CONSIDER
- Quinolone or aminoglycoside
(to double-cover pseudomonas)
-
- Duration: 8 days (traditionallly 14-21 days, but recent study shows 8 equal to 15 days)
-
- Prevention:
- Critically ill patients have oropharynx colonized with potentially pathogenic organisms.
- Oropharyngeal decontamination is looked at.
- Study:
- Bergmans et al (2001): oral decontamination with topical non-absorbable antibiotics reduces VAP
- Used 2% polymyxin, 2% tobramycin, 2% amphotericin B applied with gloved finger q6h
- Koeman et al (2006): Chlorhexidine also reduces VAP
- (Thought to avoid development of antimicrobial resistance, never compared to abx)
- 2% chlorhexidine in petroleum jelly (Vaseline) appied to orgal mucosa q6h
- 2% colistin can be added for gram-negative coverage (chlorhexidine primarily covers G+'s). Colistin not used as an antibiotic anymore, resistance to it is not a big problem.
- Bergmans et al (2001): oral decontamination with topical non-absorbable antibiotics reduces VAP
- Oral decontamination is advised to any patient that is likely to be ventilator dependent for more than few days, and continued as long as patient stays in ICU
- 2% chlorhexidine +/- 2% colistin preferred (theoretical advantage)
Atypical Mycobacteria
Fungal Pneumonias
Histoplasmosis
- Histoplasma capsulatum
- Primarily in Midwest and Southeast USA.
- Grows in moist soil in temperate climate --
- Ohio River and Mississippi River Valleys (CLASSIC)
- Exposure from soil excavation, construction, and also from Caves/buildings with bats.
- Exists as mycelia in environment, and yeast in the body.
- Converts to yeast, upregulates calcium binding protein... frequently see calcifications.
- Macrophages present histo antigens to T-cells in lymph nodes, and become activated inseveral weeks.
- Symptoms:
- Astymptomatic/mild flu-like-illness + clear in healty
- Young, Elderly, Immunocompromised:
- 14 days post-exposure
- high fever, headache, cough (no sputum), dull CP.
- CXR- patchy infiltrates, then later to "buckshot" calcifications.
- Mediastinal lymphadenopathy (like lymphoma and sarcoid).
- 14 days post-exposure
- If disseminated disease (10%)
- Meningitis, lymphocytosis, low glucose.
- Reticularnodular pattern on CXR. (CXR normal in 1/3)
- Diagnosis:
- Culture: needs selective media, lab needs to know. Takes 7 days (Not routine).
- Lysis-centrifugation.
- Bronchoscopic lavage fluid -- should test. (90% yield in HIV pts)
- Urine antigen test. (90% if disseminated, 40% if cavitary, and 20% pulmonary)
- Histopathology good too. Silver stain.
- Bottom line: Difficult to detect.
- If disseminated --> do bone marrow culture
- Treatment:
- Itraconazole is good agent. Recommended for:
- Acute pulmonary illness that fails to imrpove in 7 days.
- Extensive mediastinal involvement.
- Progressive cavitary disease.
- Amphotericin B if more severe disease.
- or if no improvement with Itraconazole
- Itraconazole is good agent. Recommended for:
Coccidiomycosis
- Coccidioides immitis
- Grows in soil; prefers dry, alkaline soil, hot summers, and winters with few freezes.
- These conditions exist in California's San Joaquin Valley in southern Arizona, New mexico, and texas
- Also in Mexico, Central America, and South America.
- Contracted in summer (dust storms, excavation, earthquakes).
- Cell-mediated immunity (Endospores).
- Sx:
- non-productive cough, fever, pleuritic chest pain, SOB, headache, fatigue.
- skin manifestations: erythema nodosum, erythema multiforme, nonpruritic papular rash.
- Eosinophilia.
- Disseminates in AIDS/HIV.
- Chronic Lung Infection: fibrosis, nodules, cavities.
- Chronic pleural effusions in young healthy athletic males.
- Dx:
- Sputum examination (or gathered by bronchoscopy)
- Easy to culture on mycology plates.
- Serology: IgG, IgM
- Tx:
- Only if disseminated disease.
- Amphotericin B
- Fluconazole or itraconazole if less severe.
Quick Summary
- CAP
- Organisms
- S. pneumo
- H. influenzae
- Moraxella
- Atypicals (Legionella, Mycoplasma, Chlamydophila)
- Rarely: S. aureus, GAS
- Treatment:
- Amoxil +/- clavulin (macroldies or resp Flouroquinolones for atypicals)
- Can step-up to ceftriaxone
- Organisms
- HCAP, Hospital Acquired Pneumonia (HAP)
- Increased rates of Gram-negatives and Pseudomonas.
- Ctx +/- atypical
- Piptazo +/- atypicals
- VAP: Piptazo.
- Aspiration Pneumonia
- Day 1-3: Aspiration PNEUMONITIS
- Day 3-5: Bacteria
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