ATYPICAL PNEUMONIAS: THE BASICS Nilesh Patel, DO October 8, 2008 St. Joseph’s Regional Medical Center
QUESTIONS WE WILL ANSWER??? What is an atypical pneumonia? What are the organisms that compromise atypical pneumonias? How do we test for atypical pneumonias; does it matter? What are the antibiotic choices? What should we think about when HIV patients present with pneumonia?
OBJECTIVES We will discuss…. Mycoplasma pneumoniae Legionella sp. Chlamydia pneumoniae Chlamydia psittaci Viral pneumonias Pneumonia in the setting of HIV/AIDS--PCP
ATYPICAL PNEUMONIA: WHAT IS IT??? Infection of pulmonary parenchyma Community-acquired Classically—do not show up on Gram stain Characteristics “Atypical” presentation/symptoms/diagnostics Insidious onset Nonproductive cough Constitutional symptoms Interstitial pattern on CXR Smoldering course The lines are “blurred” Similar to typical organisms clinically and radiographically
ORGANISMS Mycoplasma pneumonia Viral pneumonias RSV Parainfluenza Adenovirus Influenza Other Chlamydia pneumonia Chlamydia psittaci Legionella pneumophila Coxiella burnetti (Q fever pneumonia) Francisella tularensis (Tularemia)
EPIDEMIOLOGY 4 million cases CAP/year 20-60% typical organisms 10-40% atypical organisms Hard to quantify these organisms
PATHOPHYSIOLOGY
MYCOPLASMA PNEUMONIA Smallest free living organisms Prokaryotes No cell wall Most common cause of atypical pneumonia “Walking” pneumonia Community acquired Usually occur in young to middle aged patient Clinical symptoms Insidious onset, protracted course Constitutional symptoms (fevers, chills, myalgias, body aches) Sore throat, HA Dry cough Chest pain/SOB
MYCOPLASMA: DIAGNOSTICS CXR Consolidation Patchy infiltrates Interstitial pattern Pleural effusion Labs WBC Cold agglutinin assays Other serum assays Cultures Blood Sputum
MYCOPLASMA: TMT Macrolides Azithromycin Erythromycin Clarithromycin Doxycycline
LEGIONELLA Gram negative intracellular rods Fastidious Multiple serotypes Legionella pneumophila Community acquired Legionnaire’s disease Transmission from contaminated water sources Warm water environments No person to person transmission Outbreaks….Sporadic cases High mortality if not treated
LEGIONELLA Natural water habitats Water distribution systems Cooling towers Hot tubs/Spas Respiratory equipment Humidifiers Etc…… Travel Hotels Large Events Floods/Natural Disasters
LEGIONELLA: SYMPTOMS Incubation period: 2-10 days Clinical symptoms Pulmonary Cough Chest pain Dyspnea Extrap-pulmonary Constitutional symptoms GI symptoms—diarrhea, abd pain, n/v Neuro symptoms—HA, change in mental status
LEGIONELLA: DIAGNOSTICS CXR—variable Consolidation Patchy infiltrates/Interstitial infiltrates Pleural effusions Multi-lobar Labs CBC, SMA-7 (Hyponatremia, Elevated LFTs, ARF) CPK Urine antigen tests Serum legionella antibodies PCR Cultures Sputum gram stain/culture; DFA sputum Blood cultures
LEGIONELLA: TMTS Fluoroquinolones Levaquin Avelox Macrolides Zithromax Doxycycline Bactrim Rifampin Extended course Initial IV therapy
CHLAMYDIA Chlamydia 3 sp (pneumoniae, psittaci, trachomatis) Gram negative obligate intracellular organisms (parasites) Unique organisms Community acquired Chlaymydia pneumoniae Common Respiratory transmission (person to person) Pneumonia Chlaymdia psittaci Rare Ornithosis Respiratory transmission (infected birds to humans) Pneumonia/Viral illness
CHLAMYDIA PNEUMONIA Clinical symptoms Incubation period: 1-4 weeks Acute/subacute illness Self limited URI/bronchitis Fever Constitutional symptoms Cough Chest pain/sob Pharyngitis Sinusitis Rales/Rhonchi/Wheezing
CHLAYMDIA PSITACCI Risk Factors—Contact with birds Clinical symptoms (incubation 5-30 days) Acute viral illness/flu like symptoms Fever Relative bradycardia Constitutional symptoms Chest pain/sob Multi-system Neuro symptoms—HA, altered mental status HSM (elevated LFTs) Rash—Horder spots, EM, EN Rales/Rhonchi/Wheezing/Clear lungs
CHLAMYDIA: DIAGNOSTICS Chlamydia pneumonia CXR Cultures Serologic tests Chlamydia psitacci CXR Cultures Serologic tests
CHLAMYDIA: TMTS Chlamydia pneumoniae Doxycycline/Tetracycline Macrolides (Zithromax, Clarithromycin, E-mycin) Quinolones (Avelox, Levaquin) Chlamydia psitacci Doxycycline/Tetracycline Macrolides (Zithromax, E-mycin)
VIRAL PNEUMONIAS More common in pediatric population and elderly Up to 15% of all CAP cases Mild>>>>Severe Influenza A & B RSV Adenoviruses Parainfluenza SARS Avian flu Varicella CMV Herpes virus Hanta virus
ANTIBIOTICS Outpatient/Inpatient/ICU Remember coverage for CAP Mycoplasma—Macrolide, Doxy Legionella—Quinolone, Macrolide Chlaymydia pneumonia—Doxy, Macrolide Chlaymida psitacci—Doxy, Macrolide Viral pneumonias Supportive care Influenza—Tamiflu, think Staph coverage
HIV & PNEUMONIA Most common infectious process in HIV + patients Broaden differential diagnosis CD4 count & viral load important for specific organisms and prognosis CAP most common Other PCP TB MAC Histoplasmosis/Coccidiomycosis Viral pneumonias
PCP Pneumocystis carinii >> Pneumocystis jiroveci Unicellular fungus Various morphology--cysts Pre-HIV—few cases Most common opportunistic infection in HIV patients Common cause of death in HIV patients; mortality ~ 15% Decreased incidence with prophylaxis and antiretroviral treatment Transmission—human to human; airborne Pneumocystis is widespread Symptomatic disease occurs in immunosuppressed populations
PCP: CLINICAL SYMPTOMS Symptoms SOB (exertional) Cough Fevers Constitutional symptoms Chest pain Signs Tachypnea/Fever/Tachycardia Rales/RhonchiWheezing Cachexia Lymphadenopathy Cyanosis
PCP: DIAGNOSTICS Labs CBC, SMA-7 LDH ABG Imaging CXR—variable Normal>>Diffuse b/l infiltrates>>Perihilar infiltrates>>PTX CT scan Diffuse b/l infiltrates>>Ground glass appearance>>Cysts Sputum culture BAL Complication—PTX!
PCP: TMT Supportive treatments Oxygen Noninvasive/Invasive ventilation Antibiotics (14-21 days or until clinical response achieved) Bactrim IV Pentamadine IV or aerosolized Atovaquone po Other therapies Steroids—Hypoxemia, PaO2 < 70, Severe disease Prophylaxis
PCP: COMPLICATIONS Hypoxemic respiratory failure ARDS PTX Risk for other opportunistic infections
SUMMARY Atypical pneumonias Mycoplasma Legionella Chlamydia Viral pneumonias HIV & pneumonia PCP