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