Pulmonology Flashcards
Therapy for COPD exacerbation
Bronchodilators (inhaled) = nebulized albuterol
Ipratropium (inhaled)
Steroids = prednisone or methylprednisone
Antibiotics = ceftriaxone
Counseling
Influenza vaccine
Pneumococcal vaccine
List the most important features of a severe asthma exacerbation
Hyperventilation/ increased respiratory rate
Decrease in peak flow
Hypoxia
Respiratory acidosis
Possible absence of wheezing
Enumerate the minimum management for patients with SOB
Oxygen
Continuous oximeter
CXR
ABG
What is the best test to determine a diagnosis of reactive airway disease in an asymptomatic patient suspected of being asthmatic?
Methacholine stimulation testing
What class of drug is methacholine?
Synthetic acetylcholine
What happens when methacholine is administered to asthmatic?
Methacholine will decrease FEV1 if the patient has asthma.
Name the two most frequently used pulmonary function tests
FEV1 (forced expiratory volume in one second)
FVC
What is the normal adult FEV1/FVC ratio?
> 75%
Describe the obstructive pattern in PFT
An FEV 1/FVC ratio of 70%
Total lung capacity (TLC) will be increased in some obstructive processes, such as COPD, whereas it may be normal or increased in asthma.
Name some obstructive lung disease
COPD
Asthma
Chronic bronchitis
Bronchiectasis
What is the meaning of DLCO
Diffusing capacity of carbon monoxide
What does DLCO measure?
Measures the gas exchange capacity of the capilary-alveolar interface
Why is DLCO normal in asthma
Because the alveoli are not affected
What is the DLCO in COPD
The DLCO in COPD is decreased because some alveoli are destroyed and unavailable for gas exchange.
Describe the restrictive pattern in PFT
Low FEV1, low FVC, but with normal or increased FEV1/FVC
Decreased TLC
An FVC of 80% is suggestive of restriction when the FEV1/FVC ratio is normal.
Examples of diseases with restrictive pattern on PFT
Obesity
Interstitial lung disease
Inflammatory/fibrosing lung disease
Kyphosis
Define hypoxia (or hypoxemia)
Defined as a room-air O2 saturation of 88%
or a PaO2 of 55 mm Hg on ABG measurement
or evidence of cor pulmonale.
Diagnosis: Hypoxia not responding to supplemental oxygen
Shunt physiology
Examples of diseases with ventilation-perfusion (V/Q) mismatch
Asthma
COPD
Nonmassive pulmonary embolus (PE)
Pneumonia.
Features of ventilation-perfusion (V/Q) mismatch
Responds to oxygen
Increased arterial-alveolar oxygen (A-a) gradient
What is the common cause of hypoventilation?
Oversedation from medications
Features of hypoventilation
Responds to O2
Characterized by a normal A-a gradient
Features of hypoxia due to decreased diffusion
Responds to O2
Characterized by an A-a gradient
Associated with a very low DLCO.
Le, Tao; Bhushan, Vikas; Herman Bagga (2010-09-21). First Aid for the USMLE Step 3, Third Edition (First Aid USMLE) (Kindle Locations 11153-11157). McGraw-Hill. Kindle Edition.
Features of hypoxia due to high altitude
Responds to O2
Characterized by a normal A-a gradient
Causes of SOB due to shunt physiology
Acute respiratory distress syndrome
Significant lobar pneumonia
Patent foramen ovale
Patent ductus arteriosus.
Features of SOB due to shunt physiology
Typically does not respond to O2
Characterized by an increased A-a gradient
Differential diagnosis of Asthma presenting as chronic cough
Allergic rhinitis
Postnasal drip
GERD
Differential diagnosis of wheezing
Asthma
Foreign body aspiration
Laryngeal spasm or irritation
GERD
CHF
In asthma management, can inhaled corticosteroids be used in pregnancy
Yes, they are safe
What is the implication of a normal PaCO2 in during an episode of asthma exacerbation
A normal Pco2 suggests that the patient is tiring out and is about to crash
Outline the management of acute asthma
Initiate short-acting β-agonist (albuterol) therapy (nebulizer or MDI)
Administer a systemic corticosteroid such as methylprednisolone or prednisone
Begin inhaled corticosteroids as well
Follow patients closely with peak flows, and tailor therapy to the response
Chronic antibiotics (without evidence of infection), anticholinergics, cromolyn, and leukotriene antagonists are generally not useful in this setting
Outline and explain the management of chronic asthma
Rx for exercise induced asthma
Inhaled bronchodilator prior to exercise
What is the management of acute shortness of breath in a patient with COPD?
Oxygen and arterial blood gas (ABG)
Chest x-ray
Albuterol, inhaled
Ipratropium, inhaled
Bolus of steroids (e.g., methyl prednisolone)
Chest, heart, extremity, and neurological examination
If fever, sputum, and/ or a new infiltrate is present on chest x-ray, add ceftriaxone and azithromycin for community-acquired pneumonia.
When to intubate patients with COPD?
Do not intubate patients with COPD for CO2 retention alone. These patients often have chronic CO2 retention. Only intubate if there is a worsening drop in pH indicative of a worse respiratory acidosis. Serum bicarbonate is often elevated due to metabolic alkalosis as compensation for chronic respiratory acidosis.
List the typical physical findings in COPD
Barrel-shaped chest
Clubbing of fingers Increased anterior-posterior diameter of the chest Loud P2 heart sound (sign of pulmonary hypertension)
Edema as a sign of decreased right ventricular output (the blood is backing up due to the pulmonary hypertension)
Laboratory findings in COPD
EKG: Right axis deviation, right ventricular hypertrophy, right atrial hypertrophy
Chest x-ray: Flattening of the diaphragm (due to hyperinflation of the lungs), elongated heart, and substernal air trapping
CBC: Increased hematocrit is a sign of chronic hypoxia. Reactive erythrocytosis from chronic hypoxia is often microcytic. An erythropoietin level is not necessary.
Chemistry: Increased serum bicarbonate is metabolic compensation for respiratory acidosis.
ABG: Should be done even in office-based cases to assess CO2 retention and the need for chronic home oxygen based on pO2 (you expect the pCO2 to rise and the pO2 to fall).
Pulmonary function testing (PFT): You should expect to find the following:
– Decrease in FEV1
– Decrease in FVC from loss of elastic recoil of the lung
– Decrease in the FEV1/ FVC ratio
– Increase in total lung capacity from air trapping
– Increase in residual volume
– Decrease in diffusion capacity lung carbon monoxide (DLCO) caused by destruction of lung interstitium
Chronic medical therapy for COPD
Tiotropium or ipratropium inhaler
Albuterol inhaler
Pneumococcal vaccine: Heptavalent vaccine,
Pneumovax Influenza vaccine: Yearly
Smoking cessation
Long-term home oxygen if the pO2 < 55 or the oxygen saturation is < 88 percent
Name two interventions that lower mortality in COPD
Smoking cessation
Home oxygen therapy (continuous)
Spot Diagnosis: A case of COPD at an early age (< 40) in a nonsmoker who has bullae at the bases of the lungs.
Alpha-1 antitrypsin deficiency
Rx for alpha-1 antotrypsin deficiency
Alpha-1 antitrypsin infusion
What is the most accurate diagnostic test for bronchiectasis?
High-resolution CT scan of the chest.
Medication associated with lung fibrosis
Nitrofurantoin
What is the most common type of cancer in asbestosis?
Lung Cancer
(NOT MESOTHELIOMA)
Causes of silicosis
Glass workers
Mining
Sandblasting
Brickyards
Causes of berylliosis
Electronics
Ceramics
Fluorescent light bulbs
Name the interstitial lung disease caused by mercury
Pulmonary fibrosis
Name the interstitial lung disease caused by cotton
Byssinosis
Enumerate the PFT in ILD
Decreased FEV1
Decreased FVC
FEV1/FVC ratio is normal or increased
Decreased total lung capacity
Decreased DLCO
All the measures are decreased, but they are decreased proportionately.
List and explain the rare physical findings in Sarcoidosis
Eye: Uveitis that can be sight threatening
Neural: Seventh cranial nerve involvement is the most common.
Skin: Lupus pernio (purplish lesion of the skin of the face), erythema nodosum
Cardiac: Restrictive cardiomyopathy, cardiac conduction defects
Renal and hepatic involvement: Occurs without symptoms
Hypercalcemia: This occurs in a small number of patients secondary to vitamin D production by the granulomas of sarcoidosis.
Best initial test for Sarcoidosis
Chest x-ray, which always shows enlarged lymph nodes.
Most accurate diagnostic test for Sarcoidosis
Lung or lymph node biopsy showing noncaseating granulomas.
Other important but non-specific tests for Sarcoidosis
Calcium and ACE levels may be elevated, but these are not specific enough to lead to a specific diagnosis.
Bronchoalveolar lavage shows increased numbers of helper cells.
Therapy for Sarcoidosis
Steroids
Secondary causes of pulmonary hypertension
Mitral stenosis
COPD
Polycythemia vera
Chronic pulmonary emboli
Interstitial lung disease
Physical findings in pulmonary hypertension
Loud P2
Tricuspid regurgitation
Right ventricular heave
Raynaud’s phenomenon
List and explain diagnostic tests in pulmonary hypertension
Transthoracic echocardiogram (TTE): Shows right ventricular hypertrophy and enlarged right atrium
EKG: Shows the same findings as well as right axis deviation
Most accurate test: Right heart catheterization (Swan-Ganz catheterization) with increased pulmonary artery pressure
Enumerate Rx for pulmonary hypertension
Bosentan is an endothelin inhibitor that prevents growth of the vasculature of the pulmonary system.
Epoprostenol and treprostinil are prostacyclin analogs that act as pulmonary vasodilators.
Calcium channel blockers (weak efficacy)
Sildenafil
Describe pulmonary embolism (PE)
PE presents with the sudden onset of shortness of breath and clear lungs in patients with risk factors for deep venous thrombosis (DVT).
List the risk factors for DVT
Immobility
Malignancy
Trauma
Surgery, especially joint replacement
Thrombophilia, such a factor V mutation, lupus anticoagulant, or protein C and S deficiency
What are the specific physical findings in PE?
None
Diagnostic tests for PE
Chest x-ray: The most common result is normal. The most common abnormality found is atelectasis. Wedge-shaped infarction and pleural-based humps are rare.
EKG: The most common showing is sinus tachycardia. The most common abnormality is nonspecific ST-T wave changes. Right axis deviation and right bundle branch block are uncommon.
ABG: This shows hypoxia with an increased A-a gradient and mild respiratory alkalosis.
List and explain the confirmatory test for PE
Spiral CT
A spiral CT is standard to confirm the presence of a pulmonary embolus. The spiral CT is excellent if it is positive because of its specificity. The sensitivity of spiral CT may not be ideal, and the test can miss some emboli if they are small and in the periphery. The spiral CT is clearly the test of choice if the x-ray is abnormal.
V/ Q Scan
For a V/ Q scan to be accurate, the chest x-ray must be normal. The less normal the x-ray, the less accurate the V/ Q scan. This is still a good test for PE. The problem is that only a truly normal scan excludes a PE. Of patients with low-probability scans, 15 percent still have a PE, and 15 percent of those with of high-probability scans don’t have a PE.
Lower Extremity Doppler
These are excellent tests if they are positive; if positive, no further diagnostic testing is necessary. The problem is that 30 percent of PEs originate in pelvic veins, and the Doppler scan is normal even in the presence of a PE. Hence, the sensitivity of lower extremity Doppler is about 70 percent.
D-Dimer Testing
This is a very sensitive test with poor specificity. If the D-dimer is negative, PE is extremely unlikely. The best use of D-dimer testing is in a patient with a low probability of PE in whom you want a single test to exclude PE.
Angiography
Angiography is the single most accurate test for PE. Unfortunately, angiography is invasive with a significant risk of death of about 0.5 percent.
When a patient has a pulmonary embolism and there is a contraindication to anticoagulation, what should be the next line of action?
Place an inferior vena cava filter
Outline the Rx for PE
Heparin and oxygen: This is the standard of care in pulmonary embolism.
Warfarin: Should be used for at least 6 months after the use of heparin.
Venous interruption filter: This should be placed in all patients who have a contraindication to anticoagulation.
Thrombolytics: These are used in patients who are hemodynamically unstable. Hemodynamic instability can be defined as hypotension. Thrombolytics essentially replace embolectomy, which is rarely performed because of the high operative mortality.
Diagnostic tests for pleural effusion
Best initial test: Chest x-ray. Decubitus films with the patient lying on one side should be done next to see if the fluid is freely flowing.
Chest CT may add a little more detail to a chest x-ray.
Most accurate test: Thoracentesis
List the tests to be carried on pleural fluid for a patient with pleural effusion
Gram stain and culture
Acid-fast stain
Total protein (also order serum protein)
LDH (also order serum LDH)
Glucose
Cell count w/ differential
Triglycerides
pH
Name causes of transudative pleural effusion
CHF
Pulmonary embolism
Liver Cirrhosis
Nephrotic syndrome
Atelectasis
Name causes of exudative pleural effusion
Pneumonia (parapneumonic effusions)
Cancer (lung, breast, lymphoma)
Empyema
Pulmonary embolism
Tuberculosis (TB)
Collagen Vascular Diseases (RA, SLE)
Pancreatitis
Drug induced
List the features of transudative pleural effusion
LDH (lactate dehydrogenase) of pleural effusion of
LDH Pleural/Serum ratio
Protein Pleural/Serum ratio
(Remember 200, 0.6 and 0.5)
List the features of exudative pleural effusion
LDH (lactate dehydrogenase) of pleural effusion of >200 IU/mL
LDH Pleural/Serum ratio >0.6
Protein Pleural/Serum ratio >0.5
Rx of pleural effusion
Small pleural effusions do not need therapy.
Diuretics can be used, especially for those caused by congestive heart failure (CHF).
For larger effusions, especially those caused by infection (empyema), a chest tube for drainage is placed.
If the effusion is large and recurrent from a cause that cannot be corrected, pleurodesis is performed. Pleurodesis is the infusion of an irritative agent, such as bleomycin or talcum powder, into the pleural space. This inflames the pleura, causing fibrosis so the lung will stick to the chest wall. When the pleural space is eliminated, the effusion cannot reaccumulate.
If pleurodesis fails, decortication is performed. Decortication is the stripping off of the pleura from the lung so it will stick to the interior chest wall. This is an operative procedure.
Management of central sleep apnea
Central sleep apnea is managed by avoiding alcohol and sedatives.
It may respond to acetazolamide, which causes a metabolic acidosis. This may help drive respiration.
Some patients respond to medroxyprogesterone, which is also a central respiratory stimulant.
Diagnosis: Patient presents as an asthmatic with worsening asthma symptoms who is coughing up brownish mucous plugs with recurrent infiltrates. There is peripheral eosinophilia. Serum IgE is elevated. Central bronchiectasis is visible.
Allergic Bronchopulmonary Aspergillosis (ABPA)
Diagnostic tests for ABPA
Aspergillus skin testing
Measurement of IgE levels, circulating precipitins, and A. fumigatus-specific antibodies
Rx of ABPA
Corticosteroids
Itraconazole for refractory disease
List the causes of acute respiratory distress syndrome (ARDS)
Sepsis
Aspiration of gastric contents
Shock Infection: pulmonary or systemic
Lung contusion
Trauma
Toxic inhalation
Near drowning
Pancreatitis
Burns
Diagnostics tests for ARDS
Chest x-ray: This shows diffuse patchy infiltrates that become confluent. May suggest congestive failure.
Normal wedge pressure
pO2/ FIO2 ratio < 200, with the FIO2 expressed as a decimal (e.g., room air is 0.21). For example, if the pO2 is 100/ 0.21, the ratio is 476.
Rx of ARDS
Ventilatory support with low tidal volume of 6 mL per kg
Positive end expiratory pressure (PEEP) to keep the alveoli open
Prone positioning of the patient’s body
Possible use of diuretics and positive inotropes, such as dobutamine
Transfer the patient to the ICU if not already there
What is the role of steroids in ARDS?
None; they are ineffective in ARDS
Swan-Ganz (Pulmonary Artery) Catheterization. Types of shocks and features on pulm artery pressure
Most likely organism for community-acquired pneumonia (CAP)
Pneumococcus
Most likely organism for hospital-acquired pneumonia (HAP)
Gram negative bacilli
Diagnostic tests for pneumonia
Best initial diagnostic test: Chest x-ray
Most accurate test: Sputum Gram stain and culture
Order tests as follows: All cases of respiratory disease (fever, cough, sputum) should have a chest x-ray and oximeter ordered with the first screen.
If there is shortness of breath, also order oxygen with the first screen.
If there is shortness of breath and/ or hypoxia, order an ABG.
Rx for outpatient pneumonia
Macrolide (azithromycin, doxycycline, or clarithromycin)
Respiratory fluoroquinolone (levofloxacin, moxifloxacin)
Rx for inpatient pneumonia
Ceftriaxone and azithromycin
Fluoroquinolone as a single agent
What is ventilator-assisted pneumonia (VAP)?
- Fever
- Hypoxia
- New infiltrate
- Increasing secretions
Rx for VAP
- Imipenem or meropenem, piperacillin/ tazobactam or cefepime;
- Gentamicin; and
- Vancomycin or linezolid
When is steroid indicated in PCP?
Steroids are indicated if the pO2 < 70 or the A-a gradient > 35.
Patient with pneumonia who had a recent viral infection, what is the likely causative agent?
Staphylococcus
Patient with pneumonia who is an alcoholic, what is the likely causative agent?
Klebsiella
Patient with pneumonia who has gastrointestinal symptoms and confusion, what is the likely causative agent?
Legionella
Young healthy patient with pneumonia, what is the most likely causative organism?
Mycoplasma
Patient with pneumonia who was present at the birth of an animal, what is the likely causative agent?
Coxiella burneti