9/11- Pulmonary Infections Flashcards Preview

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Flashcards in 9/11- Pulmonary Infections Deck (43):

What are the various routes of infection to the lungs?

- Inhalation of contaminated droplets/aerosols

- Aspiration

- Hematogenous

- Direct extension


What are host defenses to lung infections?


- Anatomical (nasal turbinates, nasal hairs, glottis, branching airways)

- Cough reflex

- Mucociliary escalator

Immune-based responses: alveolar macrophages and surfactant proteins

- Engulf, opsonize and kill bacteria and viruses

- Release inflammatory mediators to defend the lung =>syndrome of pneumonia


What are risk factors for community acquired pneumonia?

- Alcoholism

- Asthma

- Immunosuppression

- Institutionalization

- Age > 70


Clinical manifestations of CAP?

Onset/prodrome: insidious, acute or fulminant

Severity: mild to fatal


- Fever, cough (dry or productive), pleuritic chest pain, chills or rigors, shortness of breath

- Associated symptoms: HA, nausea, vomiting, diarrhea, myalgia, fatigue


What is found on the physical exam of pt with pneumonia?

- Tachypnea

- Fremitus – increased or decreased

- Percussion – dull or flat

- Crackles

- Pleural friction rub

- Whispered pectoriloquy (increased clarity of whispered words; same connotation as bronchopony)

- Egophony – E to A (extreme bronchophony)


What are the typical etiologic agents of community acquired pneumonia? Atypical?


- Strep pneumoniae

- Hemophilus influenzae

- Staph aureus


- Klebsiella pneumoniae


- Mycoplasma pneumoniae

- Chlamydia pneumoniae

- Legionella spp

- Respiratory viruses

- Fungi

Vary according to geographic areas, patient population, season, age group

(Only find etiologic agent in 1/2 of outpts or 2/3 of inpts.. in everyday practice, 70% of cases are not identified)


What common pathogens are associated with alcoholism?

- S pneumoniae

- Oral anaerobes

Gram negative bacilli:

- Klebsiella

- Acinetobacter

- M TB


What common pathogens are associated with bronchiectasis, cystic fibrosis?

- Pseudomonas

- Burkholderia cepacia

- Staph aureus


What common pathogens are associated with COPD?

- H influenzae

- Pseudomonas

- Legionella

- S pneumoniae

- Moraxella catarrhalis


What common pathogens are associated with Flu season?

- Influenza virus

- S pneumoniae

- Staph aureus


What common pathogens are associated with exposure to water?

Legionella spp


What common pathogens are associated with poor dental hygiene?

Oral anaerobes


What common pathogens are associated with HIV?

- Pneumocystis jirovecii

- Strep pneumoniae

- Mycobaterium tuberculosis

- H influenzae


How is a CXR useful in pneumonia?

Helpful in diagnosis

- Presence/extent of infiltrate

- Presence of pleural effusion

- Follow clearing of infiltrate


When would you order a CT chest?

- Complicating factor

- Negative CXR with strong suspicion for pneumonia


What are other tests that can be used in diagnosis/management of pneumonia?

WBC count: indicate need for hospitalization (very high or very low)

Sputum Gram stain:

- Adequate lower respiratory tract specimen: fewer than 10 squamous epithelial cells and >25 PMNs per LPF

- Can identify organisms by characteristic appearance

Sputum culture

Blood culture (if admitted to hospital), low yield: 5-14%

Antigen tests: uine strep and legionella

PCR tests: Rapid flu, M TB, Legionella, Mycoplasma

Serology: mycoplasma, viruses, fungi


What is the pneumonia severity index (PSI)?

20 variables with points assigned

Severity classes I-V for point ranges with associated mortality rates 


What is the CURB 65 criteria?

- Confusion

- Urea > 7 mmol/L

- Respiratory rate > 30

- Blood pressure: SBP under 90 or DBP under 60

- Age > 65

Mortality rate:

1- 1.5%

2- 9.2%

3- 22%


How do you select antibiotics for CAP?

Strep pneumoniae: cephalosporin

Atypical pathogens: macrolide

- Evaluate risk factors for drug resistance (risk factors for community-acquired MRSA)

- Treatment should start as soon as possible


What is nosocomial pneumonia?


- Pneumonia development at least 48 hours after hospital admission


What is healthcare associated pneumonia?

- Transition between nosocomial and community acquired pneumonia

- Up to three months after health care episode (admitted for at least 2 days)

- Residence in NH

- IV antibiotics, chemo or wound care within 30 days

- Attended hemodialysis in hospital or clinic


What are common etiologies for healthcare associated pneumonia?

(Similar to nosocomial pneumonia)

Gram negative bacilli: 64%

- E coli

- Pseudomonas (21%)

- Klebsiella

- Enterobacter

Gram positives

- Staph aureus- most common single pathogen! (MRSA > 50%)


Complications of pneumonia?

- Pleural effusion – parapneumonic or empyema

- Lung abscess

- Metastatic infection

- Respiratory failure

- Septic shock

- Multiple organ failure


What immunocompromised patients/situations should be considered with pneumonia?

- HIV infection

- Organ transplantation: bone marrow and solid organs

- Malignancies: related to malignancy or its treatment (leukopenia, altered mentation, aspiration, emesis)

- Autoimmune diseases/Tx: steroids, anti-TNF


Nuances of pneumonia in immunocompromised host:

- Defenses

- Fever?


- Tx?

- Net state of immunosuppression” – host factors that contribute to infectious risk

- Fever may or may not be present

- Rate of progression of disease

- Radiographic pattern may be abnormal

- Aggressive diagnostic measures

---- Specific etiologic diagnosis is essential

---- Differential dx includes non-infectious processes

- Immediate treatment intervention


What etiologic causes of pneumonia or worrisome in the different stages of lung transplants?

Early (under 1 mo)

- Bacteria

- Aspiration

- Nosocomial pathogens

Middle (1-4 mo)

- Pneumocystic

- Aspergillus


Late (> 6 mo)

- Pneumocystis

- Granulomatous: nocardia, reactivation of fungi, mycobacteria


Epidemic of _____ is a looming threat to TB control efforts

Epidemic of diabetes mellitus is a looming threat to TB control efforts


What are risks for TB infection?

- Close contact of person with TB

- Persons from or frequent visitors to countries of high TB burden

- Congregate settings – residents and employees

- Health care workers

- Low income, drug/alcohol abuse, poor access to health care

- Infants, children, adolescents


What is MDR-TB?

Multi-drug resistant TB Resistance to both:

- Isoniazide

- Rifampin


What are characteristics of a latent TB infection (LTBI)?

- History of exposure to TB

- No symptoms

- Immune response to TB antigens

----Positive TST or

----Positive interferon gamma release assay (IGRA) – Quantiferon TB or T Spot TB

- Normal CXR


What are high risk groups for TB? What is considered positive on a tuberculin skin test (TST)?

- HIV or immunosuppressed

- Close contact of TB pt

- Abnormal CXR

Positive > 5mm


What are moderate risk groups for TB? What is considered positive on a tuberculin skin test (TST)?

- Recently infected (under 2 yrs) = recent converter

- High risk medical conditions: DM, cancer of head/neck, lung, organ transplant

Positive > 10 mm


What are low risk groups for TB? What is considered positive on a tuberculin skin test (TST)?

None of the other conditions (HIV/immunosuppressed, close contact, abnromal CXR, high risk medical conditions like DM, cancer, organ transplant...)

Positive > 15 mm


What is the natural history/course of LTBI in an HIV negative pt?

- No further problem with no evidence of active disease (90%)

- Primary infection is not well contained and active disease develops within 2 years (lower lobe, hilar, pleural) (5%)

- "Reactivation of previously contained, dormant TB (usually > 2 years after primary infection (5%)


What is the natural history/course of LTBI in an HIV pt?

Risk for active TB: 7-10% per year


Treatment of LTBI?

- Standard therapy: 4 first line drugs

---- Intensive phase = RIPE (Rifampin, Isoniazid, Pyrazinamide, Ethambutol) for 2 mo

----- Continuation phase = RI for 4 mo

- Provide safest, most effective therapy in shortest time: decrease infectivity, morbidity mortality

- Adherence to therapy- DOT, in all

- Major determinant of outcome is adherence and completion

- Children treated same as adults

- Extrapulmonary TB treated the same

- Contact investigation = key to dz prevention (pic 2)


What are risks for active TB?

- Previously untreated TB (stable, fibrotic pulmonary lesion)


- Silicosis

- Use of anti-TNF, chronic steroids

- Malignancy – head and neck, lung

- Chronic renal failure

- Diabetes mellitus

- Alcoholism

- Active smoker

- Malnutrition

- Post gastrectomy


Characteristics of primary TB (pathologically/anatomically)?

- Lower lobe involvement

- Pneumonic pattern

- Hilar LAD

- Pleural effusion


Characteristics of reactivation TB (who gets it, sites, anatomy)

- Majority of pts with active TB

- Endogenous reactivation of latent infection

- Occurs in sites that were disseminated during the primary infection

- Most common site = apical posterior segment of lung (80%)


What clinical features aid in the diagnosis of TB?

- Risk factors for exposure

- Signs and symptoms: usually chronic (wks - mos) and non-specific

Pulmonary Sx:

- Persistant cough

- Hemoptysis

- Dyspnea

Systemic Sx:

- Malaise, fatigue

- Fever

- Weight loss, anorexia

- Night sweats


How can the microbiologic diagnosis be made for TB?

Acid fast stain: Ziehl Neelsen or auramine fluorescence

- Three sputum specimens ~50% positive

- Culture: 2-6 weeks

- Drug susceptibility: 1-2 weeks

Molecular technology

- Nucleic acid amplification – PCR based

- Drug susceptibility – detect gene mutation


How can therapy be monitored?

Monthly sputum culture until negative

- 80% are culture negative in 2 months

- If positive > 2 months, repeat susceptibility

Serial CXR are not recommended

- End of treatment CXR – future comparison

Clinical evaluation monthly

- Adverse reactions and adherence to therapy

Treat co-morbidity – DM, COPD, HIV

Supportive environment



- Emerging threats to global TB control

- Treatment of LTBI – important role in TB elimination

- Clinical presentation of TB is varied

- Close clinical follow up and partnership with public health department – ensure completion of treatment

- Clinical manifestations of pneumonia are non-specific

- Epidemiologic factors are useful in narrowing the possible etiologic agents

- Treatment should be directed to the most likely pathogen(s) and initiated without delay

- Clinical features that predict mortality help guide decision for hospitalization