Infectious Pulmonary Disorders Flashcards
What are the 2 MC organisms to cause CAP?
1 = S. pneumo
What organism causes atypical pneumo (walking pneumo) ?
Mycoplasma pneumo
What organisms cause HAP?
Pseudomonas
MRSA
What does the CXR look like in typical vs atypical pneumo?
Typical = lobar pneumo
Atypical = Diffuse patchy interstitial or reticulonodular infiltrates
What are s/s of typical pneumo?
Sudden fever Productive cough, purulent sputum Pleuritic CP Rigors* Tachy, tachypnea
What are s/s of atypical pneumo?
Low grade fever
Dry, nonproductive cough
*Extrapulmonary sx: myalgia, malaise, sore throat, HA, N/V/D
What does typical pneumo look like on PE?
Signs of consolidation:
- bronchial breath sounds
- dullness to percussion
- increased tactile fremitus, egophony
What does atypical pneumo look like on PE?
Often normal
+/- crackles, rhonchi
What sx does mycoplasma pneumo cause?
ear pain, bullous myringitis
persistent dry cough, pharyngitis
How do you dx mycoplasma pneumo?
serum cold agglutinins
What sx does legionella cause?
GI sx, N/V/D, anorexia
Increased LFTs
Hyponatremia
How do you dx legionella?
Legionella urine antigen +/- PCR
What is the dx workup for pneumo?
CXR/CT: silhouette sign
- pleural effusion may be present
- abscess formation = s. aureus
- upper lobe w/ bulging fissure, cavitations = klebsiella
Sputum (gram stain/culture)
- rusty = strep pneumo
- currant jelly = klebsiella
How do you treat CAP, outpatient?
Macrolide or doxy 1st line
FQ only if comorbid conditions
How do you treat CAP, inpatient?
B lactam + macrolide OR
FQ
How do you treat CAP, ICU?
B lactam + macrolide OR
B lactam + FQ
If B lactam allergy –> FQ +/- aztreonam
How do you treat HAP, pseudomonas risk?
B lactam + AG or FQ
If MRSA suspected, + vanco
If legionella suspected, + levofloxacin or azithromycin
If PCP suspected, + TMP-SMX
How do you treat aspiration pneumo?
Clinda or metronidazole or augmentin
What is the MC viral cause of pneumo in children?
RSV & parainfluenza
What is the MC viral cause of pneumo in adults?
Influenza
Who is at increased risk for mycoplasma pneumo?
< 40yo
School-aged children
College students
Military
How does pneumo caused by chlamydophila present?
Hoarseness, URI sx
Sinusitis*
Why doesn’t mycoplasma pneumo respond to b-lactams?
Bc it lacks a cell wall!
Who is pseudomonas aeruginosa MC in?
Immunocompromised (HIV, s/p transplant)
CF, Bronchiectasis
Who is at increased risk of getting pneumo caused by CMV?
Transplant
AIDs
How does PCP present?
Fatigue, dry cough, dyspnea on exertion
A/w O2 desaturation w/ ambulation
Where is histoplasma capsulatum MC?
MIssissippi & Ohio river valley
Soil contaminated w/ bird or bat poop
Who is at increased risk of contracting TB?
Close contacts w/ active TB
Immigrants from high-prevalence areas
Immunodeficient (HIV)
When does someone normally become + on PPD test?
2-4 weeks after infection
Describe the 3 stages of TB
Primary = active inf, contagious, middle/lower lobe consolidation
Chronic (latent) = granuloma formation (may become caseating), NOT contagious
Secondary (reactivation): MC in apex/upper lobes w/ cavitary lesions, contagious
What are the s/s of TB?
Pulmonary sx: chronic, productive cough, CP, hemoptysis
Constitutional sx: night sweats, fever/chills, fatigue, anorexia, weight loss
What are s/s of extra-pulmonary TB?
Vertebral (Pott's disease) Lymph nodes (scrofula)
How do you dx TB?
Acid fast smear & sputum culture x 3 days = GOLD
CXR: excludes active TB, used as annual screening for those w/ hx of + PPD
Interferon gamma release assay
How do you treat active TB?
Total tx duration = 6 months
“RIPE”: rifampin + isoniazid + pyrazinamide + ethambutol
No longer contagious after 2 weeks of tx
How do you treat latent TB?
isoniazid + pyridoxine x 9mos
If HIV –> isoniazid + pyridoxine x 12mos
What causes acute bronchitis?
MC viruses (adenovirus)
What is the hallmark of acute bronchitis?
Cough (lasting 1-3 weeks)
How do you treat acute bronchitis?
Sx: fluids, rest, bronchodilators, antitussives
Abx have no statistical benefit
Describe the 3 phases seen in pertussis
- Catarrhal: URI sx 1-2 weeks, most contagious
- Paroxysmal: paroxysmal coughing fits w/ inspiratory whooping sound +/- emesis
- Convalescent: Resolution (coughing can last up to 6 weeks)
How do you dx pertussis?
PCR of nasopharyngeal swab = GOLD
Lymphocytosis
How do you treat pertussis?
Sx: O2, nebulizers, ventilation
Macrolides = DOC (erythromycin)
If macrolide allergic –> TMP-SMX
What are characteristics of acute bronchiolitis?
MC in children > 2 mos- 2 yo after viral infection (esp. RSV, adenovirus)
Neutrophil infiltration
Bronchial narrowing
What are characteristics of bronchiolitis obliterans (constrictive)?
Chronic inflammation & fibrosis
Collapse of bronchioles
Granulation tissue –> obstructive lung disease
Mosaic pattern on CT
How do you treat bronchiolitis obliterans?
High dose corticosteroids & immunosuppression
Lung transplant = definitive
What are characteristics of cryptogenic organizing pneumo (COP)?
Type of bronchiolitis
Persistent alveolar exudates –> fibrosis of bronchioles & alveoli
Resembles pneumo, but doesn’t respond to abx
How do you treat COP?
Corticosteroids
What are s/s of acute bronchiolitis?
Fever, URI sx 1-2 days –> respiratory distress
How do you dx acute bronchiolitis?
CXR: hyperinflation, peribronchial cuffing
Nasal washings using monoclonal Ab testing
Pulse Ox = single best predictor
How do you treat acute bronchiolitis?
Humidified O2 = mainstay of tx
IV fluids, APAP/ibuprofen
B-agonists, nebulized epi
Ribavirin (if severe lung or heart disease or immunocompromised)
How do you prevent acute bronchiolitis?
Palivizumab (used in high risk)
Handwashing
What MC causes croup?
Parainfluenza virus type 1
What are 4 s/s of croup?
- Barking cough (seal like)
- Stridor
- Hoarseness
- Dyspnea (worse at night) +/- URI sx
How do you dx croup?
Clinical
Frontal cervical radiograph: Steeple sign (subglottic narrowing of trachea)
How do you treat croup?
MIld (no stridor, no distress): cool humidified air mist, hydration, dexamethasone, O2
Mod (stridor at rest w/ mild-mod retractions): dexamethasone PO or IM, nebulized epi, obs 3-4 hrs
Severe (stridor w/ marked retractions): dexamethasone + nebulized epi & hospitalization
Which type of influenza is a/w more severe, extensive outbreaks?
A!
What are s/s of the flu?
Abrupt onset of HA, fever, chills, malaise, URI sx, pharyngitis
Myalgias MC in legs & lumbosacral area
How do you dx the flu?
Clinical
Rapid influenza test (nasal swab) or viral culture
How do you treat the flu?
Sx: APAP or salicylates
Antivirals (in those at high risk for complications)
- initiate within 48hrs
- Oseltamivir (Tamiflu)*, zanamivir, ribavirin
Amantadine, rimantadine
What causes pulmonary nodules?
Granulomatous infections: TB MC
Tumors
Inflammation
Mediastinal tumors: thymoma MC
How do you dx pulmonary nodules?
Obs: if low malignant probability. CT can assess lesion
TNA (for peripheral lesions) or bronchoscopy (for central lesions): if intermediate probability
Resection w/ biopsy: if high probability (>60%)
