L3- Pulm infections

acute bronchitis

• self limited lower resp tract infection causing inflammation of the large airway (bronchi)

  • without evidence of pneumonia

  • absence of COPD

acute bronchitis- epi

• late fall adn winter when transmission of respiratory viruses peak

acute bronchitis- etiology

• respiratory viruses (MC)

  • influenza A and B

  • parainfluenza

  • adenovirus

  • rhoniovirus

• bacterial

  • bordetella pertusis

  • mycoplasma pneumoniae

  • chlamydia pneumonia

acute bronchitis- patho

• usually causes inflammation and temporary thickening of bronchial and tracheal mucosa

• mucus prod causes airflow obstruction (sometimes wheezing present)

• transient bronchial hyperresponsiveness causes continued cough

acute bronchitis- Sx

• cough 1-3 weeks (cardinal sx)

  • media duration is 18 days

  • sputum

  • hemoptysis

• URI sx

  • may preceded or occur with cough

  • headache, nasal congestions sore throat

acute bronchitis- PE

• often normal

• may display wheezing

• should not be febrile

acute bronchitis- dx

• clinical

  • hx andPE
    no imaging needed

• sus with acute onset but persistent cough (1-3 weeks) who do not have COPD or clinical findings of pneumonia

indications for CXR

1) abnormal vital signs

• pulse >100

• RR>24

• temp>100.4

• O2 sat<95%

2) signs of consolidation

• dullness to percussion

• crackles/rales

• eophany

• tactile fremetis

acute bronchitis- tx

1) pt education

• cough is self limiting

2) Sx control

• cough

  • non pharm= throat lozenges hot tea with honey, smoking cessation

  • pharm= OTC meds (dextromorphan, guaifenesin)

• URI Sx- OTC meds

AVOID ABX OVERUSE

acute bronchitis- follow up

• s/sx to look out for and return for reeval:

  • new onset fever

  • difficulty breathing

  • sx lasting >3 weeks

  • sig bloody sputum

respiratory syncytial virus (RSV)

• paramyxovirus causing respiratory infections

• fall/winter annual outbreaks: october- january

RSV epi

• MC cause of bronchiolitis and PNA in pediatric pts <1yo

  • leading cause of hospitalization in infants

• also affects adults

  • adult risk factors:

    • comorbidities, older adults, severe immunodeficiency

RSV typical progression- peds

• 1-3 days of viral URI prodrome

  • fever, URI sx, cough

• lower respiratory infection 2-3 days later

  • worsening cough, wheezing, tachypnea

  • peaks on days 3-5 then resolves gradually

RSV severe progression- peds

• possibly respiratory distress: nasal flaring, grunting, chest retractions, use of accessory muscles

RSV clinical findings- adults

• most pts experience midl to moderate clinical disease:

  • URI sx:

    • nasal congestion, rhinorrhea, sore throat

  • lower respiratory sx:

    • cough

    • wheeze

    • dyspnea

• some adults (risk factors) develop severe disease

  • progress to pneumonia and respiratory failure

RSV workup- typical

clinical diagnosis

• compatible clinical and epidemiologic features

  • age <24 months

  • respiratory distress with wheezing

  • winter season

  • known RSV circulation

• only order RSV testing if tit will affect clinical management

  • RT-PCR = gold standard

  • testing for multiple viruses preferred

RSV workup- severe

• full workup

• labs, CXR, viral assay

  • CXR: may show opacities, consolidation, interstitial changes, hyperinflation

RSV treatment- typical

• supportive

RSV treatment- severe

• ADMIT

• supportive care

• Ribavirin: antiviral for hospitalized infants and younf children with severe lower resp tract infections due to RSV

• bronchodilators and corticosteroids are NOT routinely used

  • unless pt has asthma

RSV prevention- infants

monoclonal antibodies

1) nirsevimab

• all infants <8months born during or entering first RSV season

• children8-19 months at increased risk entering their second RSV season

  • premature, immunocomp, CF

2) clesrovimab

• also 1st lien for infants <8months before RSV season

• not approved to use in second RSV season

RSV prevention- adults

vaccines

1) arexvy

• >60yo

2) Abrysvo

• pregnant patients: 35-39 weeks

• passively transmitted antibody to protect infants

pneumonia

• pulm infection that affects one or both lungs caused by bacteria, viruses, or fungi

• leading cause of morbidity and mortality worldwide

• CAP should be part of DDx of nearly all respiratory illness

PNA- patho

• transmission: inhalation pf pathogen

  • doplets of infected person or aerosol inhalation

• colonizes in nasopharynx→ alveoli via microaspiration

• results when inoculum size is sufficient and or host immune defenses are impairs

• replication of pathogen→ inflammation adn damage of lung parenchyma

PNA classifications

• site of acquisiiton

• etiology

PNA classification- site of acquisition

1) community acquired (CAP)

• acquired outside the hospital

• ambulatory adn PNA acquired <48 hours after hospital admin

2) Nosocomial Pneumonia (HAP)

• ≥ 48 hours after endotracheal intubation

3) aspiration pneumonia

• aspiration of roropharyngeal or upper GOT IT! contents

PNA classifications- etiology

• typical PNA

  • classic features adn organisms

• atypical pneumonia

  • caused by organisms thta are no typical

• fungi

• viruses

• mycobacteria (TB) ans paraistes

PNA clinical manifestations- typical

• fever

• productive cough

• pleuritic chest pain

• dyspnea

• rigors

PNA clinical manifestations- atypical

• low grade fever

• dry, non productive cough

• extrapulm sx

  • myalgias, malaise, sore throat, n/v/d

PNA PE findings- typical

• tachypnea, tachycardia

• signs of consolidation:

  • inspiratory crackles

  • bronchial breath sounds

  • dullness to percussion

  • increased tactile fremitus

  • egophony

PNA PE findings- atypical

• pulm exam often normal

• may have crackles

PNA microbiology: typical

stain

• strep pneumo

• h influenza

• staph aureua

• moraxella cat

• klebsiella pneumo

PNA microbiology- atypical

do NOT stain

• legionella

• mycoplasma pneumo

• chlamydia pneumo

CAP- strep penumo

• MC cause of CAP

• gram (+) cocci in pairs

• classic presentation:

  • sudden onset of one time chills and rigors

  • fever

  • productive cough with rusty (blood tinged) sputum

CAP- H. influenzae

• 2nd MC cause of CAP

• gram (-) rod

• older adults (especially with underlying pulm dz)

CAP- staph aureus

• post influenza secondary infection

• cause of HAP (MRSA)

• gram(+) cocci in clusters

• CXR:

  • bilateral, multilobar infiltrates

  • cavitary lesions

CAP- klebsiella pneumo

• CAP in impaired host defenses

  • alcoholics, DM

• gram (-) rod

• “currant jelly” sputum

  • marked inflammation and necrosis causes thick, mucus like sputum that is blood tinged

• CXR:

  • can contain cavitary lesions

  • upper lobe lobar consolidation with bulging interlobar fissure

CAP- mycoplasma pneumo

• MC cause of Atypical

• “walking pneumonia”

CAP: mycoplasma pneumo- epi

• young and healthy

• summer and fall

CAP: mycoplasma pneumo- clinical manifestations

• pharyngitis and URI prodrome followed by persistent cough

• normal PE

CAP: mycoplasma pneumo-mdx testing

• CXR:

  • reticulonodular pattern or diffusem patchy interstitial infiltrates

• cold agglutinin titers- elevated

• PCR (CANT GRAM STAIN)

CAP: mycoplasma pneumo- tx

• macrolides or doxy

• levo

NO beta lactams— no cell wall!!!!

CAP: legionella spp- transmission

atypical

• contaminated water sources

  • ac units, ventilation, etc

CAP: legionella spp- clinical manifestations

• high fever, chills, cough, dyspnea

• extrapulmonary sx

  • prominent GI sx- watery diarrhea

  • neuro sx- headache, confusion, MAS

CAP: legionella spp- dx testing

• CXR- non specific

• PCR testing or urine antigen

• labs- hyponaturemia, increased ALT/AST, increased LDH, increased CK

CAP: legionella spp- tx

• macrolides OR

• respiratory FQ (levo)

CAP- viruses

• less likely

• organisms:

  • influenza

  • RSV

  • pararinfluenza

  • adenovirus

  • COVID

CAP: viruses- dx testing

• PCR testing

  • specific testing

  • respiratory pathogen panel

• CXR- depends, but will likely see opacities

CAP: viruses- tx

• supportive care

• flu- oseltamvir

• COVID

  • outpt: nirmatrelvir

disposition

• pneumonia severity index (PSI)

• CURB-65

CURB-65

≥2= admin

C- confusion

U-uremia (BUN >20)

R- resp rate (≥30)

B- BP (SBP <90 or DBP <60)

Age- ≥65yo

outpt CAP tx- NO comorbidities, etc

1) amoxicillin (narrow spectrum)

• 1st line

• indications: covers typical CAP

• covers most S. pneumonia and H. influenzae strains

2) macrolides

• indications: PCN allergy or atypical CAP

  • M. pneumonia, Legionella, C. pneumoniae

3) Doxy

• indications: PCN allergy or atypical CAP

  • M. pneumoniae

outpt CAP tx- WITH comorbidities, etc

1) combo therapy (preferred)

• macrolide (preferred) or doxy + betalactam

  • amoxacillin/clavulanate (preferred) or cefpodoxime (mild pCN allergy)

2) monotherapy

• resp FQ (levo)

  • severe PCN allergy

inpt CAP tx- no ICU admission

1) combo therapy (preferred)

• macrolide + IV beta lactam (ampicillin/sulbactam, ceftriazone, ceftaroline, cefotaxime)

2) monotherapy

• oral or IV resp FQ

• severe PCN allergy

inpt CAP tx- ICU admin + MRSA

• known MRSA , prior MRSA, gram (+) clusters

• vancomycin OR linezolid

inpt CAP tx- ICU admin + pseudomonas

• known pseudomonas, prior pseudomonas, gram (-) rods, hosp with oV Abx on last 3 months

• piperacillin/tazobactam

• cefepime

• imipenem

• meropenem

most common causes of HAP and VAP

• staph aureus (MSSA and MRSA)

• pseudomonas aeruginosa

HAP and VAP- dx

• labs, imaging, and cultures= nonspecific and unreliable

• blood cultures should be ordered

• CLINICAL DX

  • based on new lung infiltrate + associated supporting evidence including new onset sx;

    • fever

    • purulent sputum

    • leukocytosis

    • decline in O2

HAP and VAP tx

• initial empiric abx tx

  • no consensus for best regimen

  • IV abx utilized

  • dist from RSA and pseudomonas risk factors

pneumocystis pneumonia (PCP)

• pneumocystis jirivecii

• unusual fungus that doesnt respond to antifungals

• MC opportunistic infection in HIV

PCP risk factors

• immunocompromised

  • HIV, malignancy, chemotherapy, transplant recipients

PCP- clinical presentation

S/Sx

• progressive dyspnea on exertion

• fever

• nonproductive cough

PE

• hypoxemia at rest or with exertion

PCP- dx

• bronchoalveolar lavage with staining or PCR = gold standard

• increased LDH >200

• CXR:

  • diffuse bilateral perihilar infiltrates

    • interstitial or alveolar pattern

  • normal in 1/3 of pts

PCP - tx

1) Abx

• trimethoprim- sulfamethoxazole

  • preferred for tx and prophylasxis

• sulfa allerg/ADR

  • trimethoprim- dapsone

  • mild-mod dz

  • clinda-primaquine

  • atovaguone

2) steroids

• use if hypoxic

• decrease mortality and respiratory failure

aspiration PNA- patho

• inhalation of oropharyngeal and gastric microbes

aspiration PNA- oragnisms

• anaerobes

• typical CAP and HAP

aspiration PNA- risk factors

• dysphagia, neuro disorders, esophageal disorders, etc

aspiration PNA- clinical presentation

• PNA sx hours or days after aspiration

• can have foul smelling sputum

aspiration PNA- dx

• clinical sus

• CXR:

  • opacities RLL>LLL

  • right bronchus wider, shorter, and more vertical

aspiration PNA- tx

1st line

• oral: amoxacillin- clavulanate

• IV: ampicillin- sulbactam

alternative

• metronidazole + amoxicillin pr penecillin G

aspiration PNA- complications

lung abscess: area of pus or necrosis in pulm parenchyma caused by microbial inffection

• air fluid level

PNA prevention- immunizations

pneumococcal vaccines

1) PCV

• PCV20 preferred

2) PPSV23

indications:

• adults >65 (-) medical conditions

• adults 19-64 (+) medical conditions or immunocomp

bronchiectasis

• permanent, abnormal dilation and destruction of bronchial walls

• results from recurrent inflammation or infection of the aiway

• disruption of mucocilliary transport mech

bronchiectasis- etiology

• Cystic fibrosis- MC cause in US

  • mutation of CFTR gene leads to abnormal chloride an water transport

  • leads to thick viscous secretions of lungs

• recurrent infections

• alpha 1 antitrypsin def

• airway foreign body

• tumors

• immune dz

  • RA

  • allergic pilm

  • other immune

bronchiectasis- patho

1) airway inflammation

2) impaired mucocilliary clearance mucus secretion and pooling (stagnant= more prone to infection)

3) damage to the muscular and elastic components

4) infection develop

leads to bronchial dilation and eventual peribronchial fibrosis

bronchiectasis- microbio

• recurrent infections are common

• common colonizers= gram (-) rods

  • pseudomonas aeruginosa most common if CF pts

    • highly virulent and associated with poor prog

  • haemophilus influenzae most common if non CF

bronchiectasis- Sx

• chronic cough

• daily sputum prod

  • copious amnts of sputum: thick/dark brown

  • hemoptysis

• dyspnea

• rhinosinusitis

bronchiectasis- physical exam

• crackles

  • at lung base

• wheezing

bronchiectasis- workup

1) imaging

• best seen on CT

2) PFT

• obstructive pattern that is not fully reversible

3) labs

• CBC with diff

• test for CF

  • sweat chloride level

  • mutation analysis for CFTR gene

• sputum smear and culture fro bacteria, mycobacteria, and fungi

• immunoglobulin quantification

bronchiectasis- CXR findings

• abnormal with non specific findings

• linear atelectasis

• dilated and thickened airway (tram track)

• opacities

• increased bronchial markings

• cysts

bronchiectasis- high resolution CT

• definitive study for dx of bronchiectasis

• findings:

  • airway dilation

    • parallel tram lines

    • signet ring sign- pulm artery contiguous with dilated bronchus

  • lack of tapering of the airway toward periphery of chest

  • mucus plugs airway→ post obstructive air trapping

bronchiectasis- dx

clinically:

• cough on most days with tenacious sputum prod

• 1≥ exacerbations/year

• radiographic findings of bronchial airway dilation on chest CT scan

how to differentiate btwn COPD and bronchiectasis

bronchiectasis

• characteristic CT findings (dilation of airway with thickened bronchi)

• ± CF

bronchiectasis- tx

• prevention

  • flu and PNA vaccines

• airway clearance

  • chest physiotherapy

  • nebulized hypertonic or isotonic saline to loosen secretions

• inhaled bronchodilators/ICS

• exercise and pulm rehab

• abx

bronchiectasis tx- exacerbations

• if no recurrent sputum culture

  • FQ (Levo or moxi)

• recent sputum growing sensitive organisms:

  • amoxicillin-calvulanate or doxy

• prior sputum growing pseudomonas

  • cipro

  • IV abx may be required

bronchiectasis tx- long term prophylactic abx

• >3 exacerbations/year

• azythromycin