Pulmonary/COPD MS III lecture
Joseph Pidala, M.D.
July 12, 2005
1.
Dyspnea (adapted from Dr. Schwartzstein’s discussion of dyspnea in Up to Date)
i.
ATS definition: "Dyspnea is a term used to characterize a subjective
experience of breathing discomfort that is comprised of qualitatively
distinct sensations that vary in intensity. The experience derives from
interactions among multiple physiological, psychological, social, and
environmental factors, and may induce secondary physiological and
behavioral responses."
ii. Etiology of chronic dyspnea: commonly pulmonary (asthma, COPD,
interstitial lung disease) and cardiac disease (CHF, ischemia, valvular
disease, pericardial disease); also anemia, deconditioning, acid/base
disorders
iii. Helpful to think of dyspnea in terms of respiratory controller, ventilatory
pump, and gas exchanger in localizing source of dyspnea
iv.
Eliciting history: associated symptoms, precipitants/exercise tolerance,
medical history, risk factors, social history/smoking history
v.
Initial evaluation for chronic dyspnea:
1. chest xray
2. cbc
3. pulmonary function testing
4. ?suspect cardiac etiology: echocardiogram, stress testing
5. further evaluation of pulmonary etiology: chest CT
vi.
Common causes of acute dyspnea: cardiac (ischemia, CHF, tamponade),
and pulmonary (bronchospasm, PE, pneumonia, pneumothorax)
vii.
Use of BNP in assessment of acute dyspnea: Can help to differentiate
acute dyspnea from CHF (commonly with BNP > 400) from non-CHF
dyspnea (BNP < 100 has > 90% Negative predictive value)
(Rapid measurement of B-type natriuretic peptide in the
emergency diagnosis of heart failure. AU - Maisel AS, et al; N
Engl J Med 2002 Jul 18;347(3):161-7.)
o
o
1. Pulmonary function testing
Combining BNP with clinical indicators
increased predictive accuracy
Level of BNP correlated with NYHA heart
failure class
*indications – diagnosis/confirmatory, quantify severity of disease, evaluate
disease progression
a. obstructive disease
i.
ii.
iii.
iv.
v.
vi.
vii.
Examples include asthma, chronic bronchitis, emphysema,
bronchiectasis, CF (asthma will demonstrate reversibility with
bronchodilators)
Characterized by decreased FEV1, FVC, and FEV1/FVC ratio
Generally, accepted as FEV1/FVC ratio of less than 0.7
Severity according to degree of FEV1 reduction
1. > 80% normal
2. 60-80% mild
3. 40-60% moderate
4. < 40% severe (with %pred. FEV1 of 40% correlating to an
FEV1 of 1liter)
Asthma – shows obstructive pattern with reversibility by
bronchodilator challenge
Chronic bronchitis – obstructive pattern, minimal response to
bronchodilators, and normal DlCO
Emphysema - "" with decreased DlCO
a. restrictive disease
i.
ii.
iii.
Examples include interstitial lung disease, pleural disease,
obesity/chest wall, and neuromuscular disease
Characterized by restrictive pattern with decreased TLC,
FVC, FEV1; has normal to increased ratio of FEV1/FVC
Severity by degree of reduction in TLC
1. > 80% normal
2. 60-80% mild
3. 40-60% moderate
4. < 40% severe
iv. Interstitial lung disease will demonstrate decreased DlCO
1. COPD (Chronic bronchitis and emphysema)
i.
Burden of disease: 15million Americans, incidence of 10-15% of smokers
(unlikely, but consider alpha-1 antitrypsin deficiency, especially with
otherwise unexplained emphysema and cirrhosis)
ii. Clinically presenting with dyspnea, cough, chronic sputum production
iii.
Physical exam: increased AP diameter, hyperresonance, decreased breath
sounds, prolonged expiratory phase, rhonchi, wheezing
iv.
CXR: hyperinflation, flattened diaphragm, chronic markings, bullae
v.
PFT’s: obstructive pattern
vi.
EKG: poor R wave progression, R. heart strain
vii.
Chronic treatment:
i.
Supplemental Oxygen (if PaO2 < 55 or sat% < 89) decreases
mortality (Annals of Internal Medicine. 93:391, 1980)
ii.
Smoking cessation
iii. Ipratroprium, albuterol for symptomatic relief
viii. COPD exacerbation (Acute exacerbation of Chronic Bronchitis, or AECB)
i.
Ipratroprium MDI/nebs, potentially albuterol MDI/nebs
ii.
Corticosteroids – 30% decrease in primary outcome of death,
intubation, readmission for COPD or need for increased drug
treatment (N Engl J Med 340:1941, 1999)
iii. ?Antibiotics – no clear mortality benefit; exacerbations are
commonly viral rather than bacterial. Most likely bacterial etiology
includes S. pneumoniae, H. influenzae, M. catarrhalis
iv.
Supplemental oxygen
v.
Non-invasive positive pressure ventilation – Decreased need for
intubation(74-26%), decreased hospital stay, decreased
mortality(29-9%). (N Engl J Med 333:817, 1995)
vi.
Consider intubation
2. Pneumonia
i.
Consider acquisition – community vs. hospital vs. immunocompromised
vs. aspiration
ii. Microbiology
i.
CAP – commonly S. pneumoniae, H. influenza, M. catarrhalis,
Mycoplasma (others include Legionella, gram negatives, S. aureus,
strep, viruses). Usual pathogens typically will cause a lobar
pneumonia, while "atypicals" like Mycoplasma, Chlamydia etc
will often cause an interstitial pattern
ii.
Hospital acquired – more likely to include gram negatives (esp
Pseudomonas), and S. aureus (consider MRSA)
iii. Immunocompromised – all of the usual suspects, but also consider
PCP, fungi, Nocardia, atypical mycobacteria, TB, CMV, HSV
1. PCP in AIDS patients almost uniformly when CD4 < 200
a. Presents as indolent course, dyspnea, cough, fever
b. Can have multiple presentations on CXR, including
normal
c. Diagnosed with induced sputum, or
bronchoscopy/BAL
2. PCP presentation in non-AIDS patients can be more
fulminant
a. Major risk factor is immunosuppression,
corticosteroids
iv.
Aspiration – consider anaerobes
iii. Manifestations
i.
Fever, chills, dyspnea, productive cough
ii.
CXR findings, consolidation, parapneumonic effusion
iii. Sputum cultures (adequate specimen has > 25PMN, < 10epi)
iv.
Treatment
i.
CAP, not hospitalized – Azithromycin, or FQ
ii.
CAP, hospitalized – ceftriaxone/azithromycin, or FQ
iii. CAP, in ICU with suspected Pseudomonas – (zosyn + FQ +
azithro)
iv.
Hospital acquired – (IMP + FQ), or (cefepime or zosyn + tobra)
v.
Neutropenic pt – similar to hosp acquired; with persistent fever,
consider vancomycin, then empiric antifungal coverage
3. Pleural Effusion
i.
Detected by decreased breath sounds, dullness to percussion
ii.
Seen on CXR; tap effusions layering > 1cm on lateral decubitus
film
iii. Consider etiology: broadly divided into transudates vs. exudates
iv.
Classified by Light’s criteria (overall > 90% sensitive and specific)
(Light, RW, Macgregor, MI, Luchsinger, PC, Ball, WC Jr. Pleural effusions: the
diagnostic separation of transudates and exudates. Ann Intern Med 1972;
77:507.)
v.
vi.
vii.
viii.
ix.
Exudate characterized by TPeff/TPser > 0.5, LDHeff/LDHser >
0.6, or LDH > 2/3 normal
If suspicion for parapneumonic effusion, should be tapped
immediately
Transudates: (think imbalance of Starling forces) CHF, cirrhosis,
nephrosis, sometimes PE
Exudates: (think other process like inflammation, infection,
malignancy, etc) Infectious, Malignancy, PE, CVD, GI disease,
hemothorax, chylothorax, uremia, Meig’s syndrome, drug-induced
Indications for chest tube drainage: empyema (frank pus), or
complicated parapneumonic effusion (pH < 7.0, + gram stain or
cultures, glc < 40, LDH > 1000)