Section 3: Flashcards

Question

What is A-a gradient?

Answer 1

A-a gradient is alveolar-arterial gradient (PAO₂-PaO₂ gradient). It is a useful calculation for the assessment of oxygenation. A-a gradient increases with age and is only valid in room air. It is calculated as follows: PA0₂-Pa0₂gradient = 150 - 1.25 X PaCO₂ - PaO₂ i.e., A-a gradient = [150 - (1.25 X PaCO₂) - PaO₂] **This gradient is between 5 and 15 mmHg in normal young adults. It increases with all causes of hypoxemia except hypoventilation and high altitude**

Answer 2

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)

Answer 3

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

Answer 4

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

Answer 5

Smoking cessation Home oxygen therapy (continuous)

Answer 6

Alpha-1 antitrypsin deficiency

Answer 7

Alpha-1 antitrypsin infusion

Answer 8

High-resolution CT scan of the chest. ## Footnote

Answer 9

Nitrofurantoin

Answer 10

Lung Cancer | (NOT MESOTHELIOMA)

Answer 11

Glass workers Mining Sandblasting Brickyards

Answer 12

Electronics Ceramics Fluorescent light bulbs

Answer 13

Pulmonary fibrosis

Answer 14

Byssinosis

Answer 15

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.

Answer 16

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.

Answer 17

Chest x-ray, which always shows enlarged lymph nodes. ## Footnote

Answer 18

Lung or lymph node biopsy showing noncaseating granulomas. ## Footnote

Answer 19

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.

Answer 20

Mitral stenosis COPD Polycythemia vera Chronic pulmonary emboli Interstitial lung disease

Answer 21

Loud P2 Tricuspid regurgitation Right ventricular heave Raynaud’s phenomenon

Answer 22

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

Answer 23

**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**

Answer 24

**PE** presents with the **sudden onset of shortness of breath** and **clear lungs** in patients with risk factors for deep venous thrombosis (DVT). ## Footnote

Answer 25

Immobility Malignancy Trauma Surgery, especially joint replacement Thrombophilia, such a factor V mutation, lupus anticoagulant, or protein C and S deficiency

Answer 26

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.

Answer 27

**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.

Answer 28

Place an inferior vena cava filter

Answer 29

**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.

Section 3: Flashcards

(55 cards)