Pulmonary Flashcards
A-a gradient
Description
Shorthand formula
A-a gradient = Measured PaO2 - Calculated PaO2
Quick A-a formula: 150 – (PaCO2 x 1.2 + PaO2)
Elevated A-a gradient ddx
V/Q Mismatch
–(PE, pneumonia, asthma)
Impaired O2 diffusion
–(interstitial pneumonia, PCP)
Right to Left Shunt
–(congenital heart disease)
Normal A-a gradient ddx
Hypoventilation
–(opioid OD)
Decreased FiO2
–(high altitude)
Central cyanosis clinically apparent with hemoglobin greater than
saturated carboxyhemoglobin looks like SaO2
saturated methemoglobin looks like SaO2
5 g/dL
100%
85%
Asthma pathophysiology
Bronchial *** and ***
Mucous ***
Increased *** cells
Bronchial muscle ***
Bronchial constriction and edema
Mucous plugging
Increased goblet cells
Bronchial muscle hypertrophy
Samter’s triad
asthma, recurrent sinus disease with nasal polyps, and a sensitivity to aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs)
Asthma miscellaneous
measurement predicting need for admission
Hemodynamic sequelae
FEV1
hypotension, pulsus paradoxus
Death risk factors (just for review)
- Hx of sudden severe exacerbations
- Prior intubation
- Prior ICU admit
- >1 admission or >2 ED visits in past year
- ED visit in past month
- >2 adrenergic MDIs per month
- Current/recent systemic steroid use
- “Poor perceivers”
- Concomitant disease – cardiopulmonary or psychosocial
- Illicit drug use
Asthma
beta-2 agonists comparison review
–Inhaled superior to oral and parenteral routes, fewer side effects
–Intermittent equal to continuous administration
–MDIs equal to nebulizers
–Racemic equal to “R” enantiomer preparations (levalbuterol)
Asthma, mechanism of action
steroids (3)
inhaled anticholinergic
magnesium
ketamine
steroids: immunomodulatory, up regulates beta receptors, immediately causes vasoconstriction
inhaled anticholinergic: relaxes bronchial smooth muscle
magnesium: relaxes bronchial smooth muscle
ketamine: sedation and bronchodilation
Cardiac arrest, intubated asthma patient steps (4)
1 Disconnect ventilator
2 Compress chest
3 Bilateral chest tubes
4 Fluid bolus
Bronchiolitis medication for congenitally ill child
Ribavirin
COPD
unique pathophysiology from asthma
–Different inflammatory markers from asthma (e.g. neutrophils, not eosinophils)
–Proteases and oxidants result in tissue destruction
- airflow reduction is not fully reversible and generally progressive
COPD
long-term natural history (4)
–Destruction of pulmonary vascular bed and thickened vessel walls
–Pulmonary hypertension
–Polycythemia
–Right sided heart failure (cor pulmonale)
In the setting of COPD exacerbation
Deep sulcus sign on the left suggestive of occult pneumothorax
COPD pneumothorax caveat
Blebs can mimic pneumothorax as shown on the x-ray
In the setting of COPD exacerbation
Lobar atelectasis distinguished from pneumonia by
sudden decompensation
volume loss on the affected side
may be treated by bronchoscopy
COPD therapy
indication for antibiotics
disease altering interventions (3)
abx: increased sputum production and purulent
smoking cessation and home oxygen (for PaO2 < 55 or Cor Pulmonale)- > mortality benefit
pneumococcal vaccination
ARDS
description
diagnostic criteria (3)
Non-cardiogenic pulmonary edema due to leaky alveolar capillary membranes
Diagnosis:
1 HypoxiaPaO2 < 60 mm Hg with FiO2 > 0.5
2 Normal ventricular function: PCWP < 18 mm Hg
3 Diffuse alveolar infiltrates: with normal heart size
ARDS
review of causes with most common
–Sepsis (most common)
–Trauma
–Near-drowning
–Aspiration
–Toxicologic (ASA, opiates, hydrocarbons)
–Pancreatitis
–Environmental (high-altitude)
–Fat or amniotic fluid embolus
–CNS catastrophe (e.g. SAH)
ARDS
treatment (4)
PEEP/CPAP
pressure controlled/high-frequency ventilation
low tidal volume ~6 mL/kg
prone position
Pneumonia mimics
including “*** lung”, *** gas
- Cancer
- Tuberculosis
- Pulmonary embolus
- Toxicologic / environmental: Chlorine gas, Farmer’s lung (allergic reaction to inhalation of moldy crops – hay, grain, tobacco)
- ARDS e.g. from chronic ASA toxicity or other treatable cause
- Atelectasis
- Right-sided endocarditis with Septic emboli
- Diffuse alveolar hemorrhage: Low hemoglobin, immune disease
Multiple “cannonball” infiltrates
Suggestive of metastatic disease, septic emboli, right sided-endocarditis
Hamptons hump: wedge-shaped pulmonary infarction broadest at the pleural edge suggestive of pulmonary embolism
Pneumonia microbial risk associations
COPD/smoker
post viral/IVDA
alcoholics, COPD, diabetics
nosocomial, immunocompromised, CF
alcoholics, poor dentition
COPD/smoker: Haemophilus influenza
post viral/IVDA: staph aureus
alcoholics, COPD, diabetics: Klebsiella
nosocomial, immunocompromised, CF: Pseudomonas
alcoholics, poor dentition: anaerobes
Noninfectious plural effusion associations
right (2)
left (3)
right (2): aortic dissection, Boerhaave’s
left (3): CHF, pancreatitis, hepatitis
Infectious pleural effusion associations (5)
Strep pneumonia, staph aureus, Haemophilus influenza, TB, Legionella
Lung abscess associations (4) including most common
Anaerobes (most common cause), Staph aureus, Pseudomonas, TB
Atypical pneumonia associations
Mycoplasma chlamydia pneumonia (age, assoc clinical finding)
Legionella (source, assoc clincal findings, transmission pearl, sputum smear result)
Mycoplasma: young adults, extra pulmonary findings (see below)*
chlamydia pneumonia: infants and young adults, conjunctivitis
Legionella: water, air conditioning, older man, no person to person spread, sputum smear negative)
*Guillain-Barré, encephalitis, hemolysis, cold agglutinins, bullous myringitis, erythema multiforme
Really atypical pneumonia
Fungal (3), CXR findings
Zoonotic (2) and sources
Cocci (Southwest), Histo (Miss river valley), Blasto (SE US); CXR: hilar adenopathy, patchy infiltrates
Q fever (Coxiella Burnetii - Vets, farmers -> sheep, goats, cattle); Hepatitis and endocarditis
Psittacosis: Bird handler; brady, sepsis, low WBC
Pneumonia Gram stains
Pneumonia treatment by class
outpatient, young, healthy
inpatient, older, sicker
healthcare associated
outpatient, young, healthy: macrolide
inpatient, older, sicker: macrolide plus cephalosporin or quinolone
healthcare associated: antipseudomonal penicillin, carbopenem or aminoglycoside
Uncommon pneumonias
- Southwest US, rodent excreta; tx
- fleas/rodents, squirrels; tx
- Inhaled bioagent; spread, classic xray, tx (3)
- Hantavirus, supportive therapy only
- Yersinia pestis (plague); doxycycline, fluoroquinolone, aminoglycoside
- Anthrax; no person-to-person spread, prominent mediastinum due to hemorrhagic mediastinitis; doxycycline, FQ, PCN
Pneumonia in HIV, common types
Bacterial:
Mycobacterial:
Parasitic:
Viruses:
Fungal:
Bacterial: Most common, Same pathogens as non-AIDS
Mycobacterial: TB, Mycobacterium avium complex (MAC)
Parasitic: Toxoplasmosis
Viruses: CMV, HSV
Fungal: PCP
Often disseminated
Cryptococcosis, histoplasmosis, aspergillosis, candidiasis
Noninfectious: Kaposi’s sarcoma and non-Hodgkin’s lymphoma
Pneumonia and HIV by CD4
< 200 (2), dx pearl, tx (3 + 1)
< 50 (3)
< 200: PCP (elevated LDH, sens not spec), TB
< 50: CMV, MAC, fungal,
PCP tx: Septra, Pentamadine, Dapsone, steroids pO2 < 70 or A-a gradient > 35
Foreign body aspiration
method to detect occult aspiration
Decubitus film showing failure of affected lung to deflate when mainstem bronchus is blocked
Aspiration PNA abx timing
Hold antibiotics until febrile to avoid selecting out resistant organisms
Tuberculosis
location-primary
location - reactivation
progression within and after two years rate
sensitivity of AFB smear
Right lower or middle lobe
upper lobe, can be cavitary
5% for each
x-ray shows cavitary right upper lobe lesion
sensitivity: only 60%
Miliary TB from hematogenous spread
Tuberculosis
isoniazid side effects (2)
positive TB skin test
Hepatitis and peripheral neuropathy
5 mm: high-risk (HIV, close contacts, chest x-ray changes, immunosuppressed)
10 mm: medium risk (immigration less than five years from high-risk area, IVDU, working high-risk setting, comorbidities, children < 5 etc)
15 mm: low risk
Sarcoidosis
classic quadrad (4) of findings
Treat flares/complications with
Bilateral hilar adenopathy, pulmonary infiltrates, ocular and skin lesions
Tx: steroids
Mediastinal masses
anterior - most common and mnemonic (5)
Bronchogenic cancer
•Mass in anterior mediastinum: five “T”s
–Thymoma (consider myasthenia gravis)
–Thyroid (retrosternal)
–Teratoma (teeth, hair, etc.)
–T cell lymphoma
–”Terrible“ (carcinoma)
Hemoptysis
most common cause
definition of massive
Tx massive:
Breathing (2),
definitive (2)
most common cause: bronchitis
definition of massive: > 600 ML 24 hours were 50 ML in single cough
Breathing (2): decubitus with bleeding side down, selective mainstem intubation
definitive (2): surgery, bronchial artery embolization, bronchoscopy
Pneumomediastinum, often benign but
In trauma consider
non-trauma consider
eponym for physical finding
In trauma consider: tracheobronchial injury
non-trauma consider: Boerhaave’s
eponym for physical finding: Hamman’s crunch synchronus with heart sounds
Pneumomediastinum
also seen on lateral neck film just anterior to vertebral bodies
Pleural effusion
transudative versus exudative
Transudate lab findings (3)
transudative: increased hydrostatic or decreased oncotic pressure (eg CHF, cirrhosis)
exudative: neoplastic, inflammatory, infectious
Transudate lab findings: low protein (<3 mg/dL), LDH < 200, pleural:serum prot < 0.5
Pulmonary embolism
Westermark’s Sign
EKG signs of right ventricular strain (6)
D-dimer ELISA vs Latex agluttination
Westermark’s Sign: relative oligemia (decreased vascular lung markings) distal to large PE
ELISA superior
RV strain:
Inverted T waves V1-V4
S1Q3T3
RBBB
P pulmonale
Right axis deviation
Tachycardia
Pulmonary embolism
Treatment options (4)
Heparin: 80u/kg bolus, followed by 18u/hour infusion
IVC Filter (Greenfield): when anticoagulation is contraindicated
Fibrinolytics (tPA): Now indicated only for PE causing shock with RV strain
Surgical embolectomy: Rarely indicated, needs bypass
Tracheostomy respiratory distress steps (3)
Bleeding steps (life threatening bleed can come from innominate artery)
- Remove inner cannula, suction, irrigate with saline
- Replace entire trach (over catheter as needed)
- Look for other cause
Bleeding: hyperinflation of balloon with levering of tube posteriorly; inntubate patient, place finger in trach hole (but not in trachea) and apply posterior pressure
