Pulmonary Flashcards
Alveolar O2 formula?
Normal A-a gradient?
PAO2 = 713*FiO2 - PaCO2/0.8
On room air (21% O2), this is:
PAO2 = 150 - PaCO2/0.8
Normal A-a gradient is <15 mm Hg.
Increases with aging but should always be <30 mm Hg
Cause(s) of hypoxemia with a normal A-a gradient
Hypoventilation, low inspired oxygen
(Everything else that causes hypoxemia - V/Q mismatch, shunts, barriers to diffusion - causes an elevated A-a gradient).
Light criteria for an exudative effusion
At least one of:
- Pleural fluid protein / serum protein ratio > 0.5
- Pleural fluid LDH / serum LDH ratio > 0.6
- Pleural fluid LDH > 2/3 the upper limit of normal for serum LDH
Diagnostic workup of new pleural effusion
Thoracocentesis, unless clearly due to CHF
Berlin Criteria (2012) for diagnosis of ARDS
- Acute onset within 1 week of insult
- Bilateral CXR opacities not explained by other lung pathology
- Respiratory failure not explained by heart failure or volume overload
- Decreased PaO2 / FiO2 ratio, <300, on at least 5 cm H2O of pEEP
How can the severity of ARDS be graded?
PaO2 / FiO2 (P/F) ratio:
<100: Severe
<101-200: Moderate
<201-300: Mild
CXR finding in ARDS?
What else can cause a similar image?
Bilateral lung opacities (pulmonary edema)
Can also be seen in CHF and volume overload
What is a key intervention in ARDS?
PEEP, up to 15-20 cm H2O
O2 saturation goal in ARDS
88-95% saturation (PaO2 55-80)
In a ventilated patient with volume control, what can cause an elevated peak inspiratory pressure (PIP)?
How can you tell the difference?
Increased airway resistance or decreased pulmonary compliance
Check with inspiratory hold:
- The “Plateau Pressure” here reflects only pulmonary compliance.
- The difference between this and PIP (the “Delta Pressure” reflects airway resistance.
Extrapulmonary involvement of sarcoidosis (5)
- Skin lesions (e.g. erythema nodosum)
- Uveitis
- Arthralgias
- Hypercalcemia
- Heart disease
Sarcoidosis on CXR
Bilateral hilar lymphadenopathy, reticular infiltrates, +/- scattered opacities
What is Lofgren syndrome?
Acute sarcoidosis with erythema nodosum and arthralgias
Manifestations of sarcoidosis heart disease
- Restrictive cardiomyopathy early, dilated cardiomyopathy late
- AV block and other conduction defects
- Arrhythmias and sudden cardiac death
(Seen in 5% of sarcoidosis patients, due to noncaseating granuloma in the heart)
Mechanism of hypercalcemia in sarcoidosis?
Treatment?
Mechanism: 1-alpha hydroxylse in the granuloma activates viatmin D (converts 25-vitamin D to 1,25-vitamin D)
Treatment: Glucocorticoids (reduce activation by the granuloma)
Treatment for sarcoidosis
Monitor if asymptomatic.
Glucocorticoids if symptomatic
Hypoxia with a petechial rash and neurological signs after trauma
Fat embolism from long-bone fracture to lungs
Mechanism of secondary spontaneous pneumothorax
Rupture of alveolar blebs due to chronic destruction of alveolar sacks
(seen in chronic lung disease like COPD and CF)
Diagnostic test for aspiration pneumonitis?
Treatment?
Diagnosis: upright CXR
Treatment: supportive care only
Pattern of PFTs and DLCO in interstitial lung disease
Restrictive pattern and decreased DLCO (restrictive pattern with normal DLCO seen with chest wall deformities)
Time course of aspiration pneumonitis and pneumonia
Pneumonitis: cough +/- hypoxemia within hours of aspiration of gastric contents
Pneumonia: symptoms several days after aspiration of oropharyngeal secretions
Hypersensitivity pneumonitis:
Presentation?
CXR findings?
Presentation: cough, dyspnea, fever, malaise (so it is pneumonia-like) in association with trigger (bird droppings, molds in farming)
CXR: Ground glass / hazy opacities
Secondary polycythemia in an obese man - likely diagnosis?
Obstructive sleep apnea
Three most common causes of chronic cough?
An initial test/trial in each?
- Postnasal drip (upper-airway cough syndrome) (try empiric antihistamine)
- Asthma (PFTs)
- GERD (try empiric PPI)
Mechanism of chronic nonproductive cough in ACEIs
Decreased metabolism of kinins and substance P
Most effective treatment for allergic rhinitis
Glucocorticoid nasal sprays (fluticasone, mometasone)
Oropharyngeal physical exam finding that may be seen in allergic rhinitis?
Pharyngeal cobblestoning (streaks of lymphoid tissue)
Appearance of flow-volume loop in obstructive lung disease
Scooped-out pattern during exhalation (low flow in later, effort-independent phase)
Pattern of PFTs and DLCO in asthma
PFTs: Obstruction (FEV1/FVC < 0.7) that is reversible, >12% increase in FEV1 w/ bronchodilator
DLCO: normal
Pattern of PFTs and DLCO in COPD
PFTs: Obstruction (FEV1/FVC < 0.7) that is irreversible or only partially reversible
DLCO: often reduced but may be normal in early disease
Patient with severe asthma attack has normal PaCO2. Next step?
Intubation (impending respiratory failure)
Pulsus paradoxus with a normal heart, pericardial space, and pericardium
Severe asthma and COPD (when generating highly negative (up to 40 mm Hg) intrathoracic pressures during inspiration, so blood pools in lungs)
Asthma, chronic rhinosinusitis with nasal polyps, and bronchospasm after receiving a medication
Aspirin-induced respiratory disease (AERD) (can be seen with any NSAID)
Sensory complication of aspirin-induced respiratory disease
Anosmia (due to nasal polyps from chronic rhinosinusitis)
When is long-term suppelemntal oxygen started in COPD?
SaO2 < 89% (PaO2 55 mm Hg) ORA in patients with cor pulmonale, right heart failure, or hematocrit >55%
SaO2 <88% (PaO2 <59 mm Hg) ORA in anyone else
Mechanisms of oxygen-induced CO2 retention in COPD
- Decreased respiratory drive
- V/Q mismatch (normally poorly perfused areas get more perfused due to more O2)
- Haldane effect (CO2 binds better to deoxygenated blood)
Some common causes of digital clubbing
What is something noteable that does NOT cause digital clubbing?
Causes: Lung cancer, chronic lung infection, interstitial pulmonary fibrosis, endocarditis, cyanotic congenital heart disease
COPD alone does NOT cause digital clubbing (so think cancer if you see this)
Theophylline toxicity
- CNS stimulation (headache, insomnia, seizures)
- Arrhythmia
- GI effects (N/V)
(Can be induced by illness or inhibition of cytochromes)
Treatment for all acute COPD exacerbations?
Moderate-to-severe? How is this defined?
- Oxygen (to SpO2 of 88-92%)
- Inhaled bronchodilators
- Systemic glucocorticoids
Moderate-to-severe: add antibiotics
Moderate-to-severe: at least 2 cardinal symptoms (increased dyspnea, increased sputum volume, incerased sputum purulence) or need for NPPV or intubation
What can be done to delay or avoid intubation in a COPD exacerbation?
Non-invasive positive pressure ventilation (NPPV)
Cardinal symptoms of COPD exacerbation
- Increased dyspnea
- Increased sputum volume
- Increased sputum purulence
Cause of panacinar emphysema in a young person?
Manifestation outside the lung
Alpha-1-antitrypsin (AAT) deficiency
Also leads to liver disease (e.g. hepatitis, cirrhosis, HCC)
CT finding that is pathognomonic for PE
Opacified wedge-shaped infarct
Rare but specific signs of PE on CXR (3)
Westermark’s sign: area of hyperlucency distal to a visible pulmonary vessel
Hampton’s hump: peripheral wedge of lung opacity due to infarct
Fleischner sign: enlarged pulmonary artery
Rare but classic sign of PE on EKG
S1Q3T3:
- Deep S wave in I
- Q wave in III
- Inverted T wave in III
Treatment for PE with hemodynamic instability
Thrombolytics, if they are not contraindicated (if fails or CI, then go to embolectomy)
Poor prognostic factors on EKG after PE
Atrial fibrillation, RBBB
When do you empirically anticoatulate prior to imaging in PE?
- PE likely by Wells criteria
- Moderate-to-severe respiratory distress
- No reltive CI to coagulation
Modified Wells criteria for PE
3 points: - Clinical signs of DVT - Alternate diagnosis less likely 1.5 points: - Previous DVT or PE - Tachycardia (>100) - Recent surgery/immobilization 1 point: - Hemoptysis - Cancer
PE unlikely if 4 or less, likely if over 4 (4.5 or more)
(Original criteria was 2 or less was low, 2-6 was moderate, and over 6 was high)
Diagnostic test if DVT is likely but no signs of PE
LE Ultrasound
Do NOT go looking for PE with CTA or V/Q scan unless they have signs of PE
Follow up of first unprovoked venous thromboembolism
CXR and age-appropriate cancer screening
If other signs of malignancy (e.g. weight loss, pain), then perform more extensive cancer screening (e.g. CT chest/abdomen/pelvis)
(Generally only test for inherited thrombophilias with suggestive history - family history, age unde 45, recurrence, multiple/unusual sites)
Options for initial monotherapy of PE or DVT
Direct Factor Xa inhibitors: Rivoroxaban, apixaban
Warfarin and dabigatran require initial treatment with heparin as well
Who should get an IVC filter?
Proximal DVT (popliteal on up) without severe swelling or limb-threatening ischemia and with CI to anticoagulation or in whom appropriate anticoagulation has failed.
Who should receive antivirals for influenza?
- High risk for complications (65 or older, chronic illness, pregnancy)
- Anyone who presents within 48 hours of symptom onset
Treatment for acute bronchitis
Symptomatic treatment
Most common causes of post-influenza pneumonia
Pneumococcus and Staph aureus
Rapidly progressing, necrotizing post-influenza pneumonia in a young person
Staph aureus
Pneumococcal vaccine recommendations
Over 65: both PCV13 and PPSV23
Risk for encapuslated organisms (asplenic, immunocompromise): both PCV13 and PPSV23
Other chronic disease under 65: PPSV23 alone
First-line treatment for community acquired pneumonia
No recent antibiotics or major comorbidities: macrolide (e.g. azithromycin) or doxycycline
With recent antibiotics or comorbidities: add a beta-lactam (e.g. ceftriaxone), or just use a respiratory fluoroquinolone (e.g. levofloxacin or moxifloxacin)
Tool for predicting community-acquired pneumonia severity and management:
CURB-65: one point for each of Confusion Urea >20 Respirations >30 BP low (systolic <90, diastolic <60) 65 years or older
0: low mortality, outpatient
1-2: Intermediate mortality, likely admission
3 or more: high mortality, urgent admission
Treatment for empyema?
Drainage and 2-4 weeks antibiotics
Fever, productive cough, large pleural effusion, and pleuritic chest pain in a patient with pneumonia
Empyema
Types of effusion associated with pneumonia?
Criteria for each?
Treatment for each?
Uncomplicated parapneumonic effusion: Few WBCs (<50,000), relatively normal pH (>7.2), glucose may be normal or low
Complicated parapneumonic effusion: Many WBCs (>50,000), acidic pH (<7.2), low glucose (<60)
Empyema: frank pus in the pleural space, lab values like complicated
Treatment: uncomplicated requires antibiotics only. Complicated and empyema require drainage and antibiotics.
Presentation of bronchiectasis
Diagnostic test(s)? Findings?
Chronic cough with large amounts of mucopurulent speeding (+/- hemoptysis, dyspnea, congestion, fatigue, weight loss).
Test: high-resolution CT, shows bronchial dilation and bronchial wall thickening
Treatment options for pneumonia when aspiration suspected
- Amp/sulbactam (IV if inpatient) or amoxicillin/clavulanate (PO if outpatient)
- Clindamycin
- Metronidazole + amoxicillin or penicillin
Most common organisms for ventilator-associated pnuemonia
Gram-negative rods (Pseudomonis, E. coli, Klebsiella pneumonia) or gram positive cocci (Strep and Staph aureus)
Causes of pneumonia with high fever and relative bradycardia
Legionella and Chlamydia (both intracellular gram negatives)
Common cause of pneumonia with high fever and diarrhea?
Diagnostic test?
Bug: Legionella
Test: Urine Legionella antigen
Pneumonia associated with hyponatremia
Legionella (damage to JG cells that secrete renin)
Treatment for Legionella
Fluoroquinolones (levofloxacin) or macrolides (azithromycin)
TB patient on RIPE has mild AST/ALT elevation. Next step?
Continue (due to isoniazid, will likely resolve)
If frank hepatitis occurs, then must stop isoniazid and switch to second-line medications
Triad of digital clubbing, arthralgias, and ossifying periostitis
Hypertrophic pulmonary osteoarthropathy (HPOA): excess proliferation of skin and bone associated with lung disease such as lung cancer, mesothelioma, TB, bronchiectasis, emphysema
Definition of single pulmonary nodule
- Single rounded opacity
- <3 cm
- Completely surrounding by lung parencyhma
- No associated lymphadenopathy
Management of SPN with benign features on CT?
Suspicious for malignancy?
Intermediate?
Benign serial CT
Suspicious for malignancy: surgical excision
Intermediate - go to size:
If 8 mm or larger: biopsy or FDG-PET
If 4 mm or less and low cancer risk: no follow-up
5-7 mm or 4 or less with intermediate risk: serial CT
Specific symptoms of Pancoast tumors
- Referred shoulder pain
- Horner symptom (sympathetic chain invasion)
- Brachial plexus invasion leading to arm motor and sensory symptoms
- Supraclavicular lymph node
Paraneoplastic syndrome(s) associated with lung SCC
Hypercalcemia (PTHrp)
Paraneoplastic syndrome(s) associated with small cell lung cancer
- Cushing syndrome (ACTH production)
- SIADH
- Lam`bert-Eaton myasthenic syndrome (antibodies against NMJ Ca2+ channels)
Lung cancer most associated with necrotizing and cavitation on CT
SCC
Location of different types of lung cancer
SCC and SCLC: central
Adenocarcinoma and large cell: peripheral
Hallmark of asbestosis on CXR
Pleural plaques
Bibasilar reticulonodular infiltrates, honeycombing, and bilateral pleural thickening may be seen
Recurrent pneumonia in the same area of lung: diagnostic test?
CT to look for obstructing mass
