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USMLE Step 1. > Pulmonary > Flashcards

Flashcards in Pulmonary Deck (29):
1

Right shift in oxygen-hemoglobin dissociation curve

ACE BATs right handed

Acid
CO2
Exercise
2,3-BPG
Altitude
Temperature

2

Rhinosinusitis

Obstruction of sinus drainage into nasal cavity leading to inflammation and pain over affected area

usually maxillary sinus in adults

Most common acute cause is viral URI - my cause superimposed bacterial infection (Strep pneumo, H flu, M catarrhalis)

3

Epistaxis

Nose bleed

Most commonly occurs in anterior segment of nostril (Kiesselbach plexus).

Life-threatening hemorrhage occurs in posterior segment (sphenopalatine artery, a branch of maxillary artery)

4

Deep venous thrombosis

Blood clot within a deep vein leading to swelling, redness, warmth, and pain. Predisposed by Virchow Triad (SHE)

Stasis
Hypercoagulability (defect in coagulation cascade proteins, such as factor V Leiden)
Endothelial damage (exposed collagen triggers clotting cascade)

Approx 95% of pulmonary emboli arise from proximal deep veins of lower extremity

Homan sign - dorsiflexion of foot leads to calf pain

use unfractionated heparins (enoxaparin) for prophylaxis and acute management

Use oral anticoagulants (warfarin, rivaroxaban) for treatment (long-term prevention)

5

Chronic Bronchitis

An obstructive lung disease

Hyperplasia of mucus-secreting glands in bronchi leads to Reid index (thickness of gland layer/total thickness of bronchial wall) of more than 50%

Productive cough for more than 3 months per year (not necessarily consecutive) for more than 2 years

Findings: Wheezing, crackles, cyanosis (early onset hypoxemia due to shunting), late onset dyspnea, CO2 retention (hypercapnia), secondary polycythemia

Blue Bloater

6

Emphysema

An obstructive lung disease

Enlargement of air spaces, reduced recoil, more compliance, low diffusing capacity for CO resulting from destruction of alveolar walls. Two types:
1) Centriacinar - associated with smoking
2) Panacinar - associated with alpha1-antitrypsin deficiency

Increased elastase activity leads to loss of elastic fibers leading to increased lung compliance

Exhalation through pursed lips to increased airway pressure and prevent airway collapse during respiration

Barrel-shaped chest

Pink Puffer

7

Asthma

An obstructive lung disease

Bronchial hyperresponsiveness causes reversible bronchoconstriction. Smooth muscle hypertrophy, Curschmann spirals (shed epithelium forms whorled mucus plugs) and Charcot-Leyden crystals (eosinophilic, hexagonal, double-pointed, needle-like crystals formed from breakdown of eosinophils in sputum)

Can be triggered by viral URIs, allergens, stress.

Test with methacholine challenge

Findings: cough, wheezing, tachypnea, dyspnea, hypoxemia, low inspiratory/expiratory ratio, pulsus paradoxus, mucus plugging

8

Bronchiectasis

Chronic necrotizing infection of bronchi leads to permanently dilated airways, purulent sputum, recurrent infections, hemoptysis

Associated with bronchial obstruction, poor ciliary motility (smoking, Kartagener syndrome), cystic fibrosis, allergic bronchopulmonary aspergillosis

9

Restrictive lung diseases

Restricted lung expansion causes lower lung volume (low FVC and TLC). PFTS: FEV1/FVC ratio higher than 80%

10

Types of restrictive lung diseases and examples

1) Poor breathing mechanics (extrapulmonary, peripheral hypoventilation, normal A-a gradient):
- Poor muscular effort (polio, myasthenia gravis)
- Poor structural apparatus (scoliosis, morbid obesity)

2) Interstitial lung diseases (pulmonary lower diffusion capacity, high A-a gradient) - 10
- ARDS
- Neonatal respiratory distress NRDS (hyaline membrane disease)
- Pneumoconioses (anthracosis, silicosis, asbestosis)
- Sarcoidosis: bilateral hilar lymphadenopathy, noncaseating granulomas; high ACE and high Ca
- Idiopathic pulmonary fibrosis (repeated cycles of lung injury and wound healing with high collagen deposition)
- Goodpasture
- Granulomatosis with polyangiitis (Wegener)
- Langerhans Cell Histiocytosis (Eosinophilic granuloma)
- Hypersenstivity pneumonitis
- Drug toxicity (bleomycin, busulfan, amiodarone, methotrexate)

11

Hypersensitivity pneumonitis

Mixed type III/IV hypersensitivity reaction to environmental antigen leads to dyspnea, cough, chest tightness, headache.

Often seen in farmers and those exposed to birds

12

Pneumoconioses

Coal worker's pneumoconiosism silicosis, and asbestosis

Higher risk of Cor Pulmonale and Caplan Syndrome (RA + pneumoconioses + intrapulmonary nodules)

13

Asbestosis

A pneumoconiosis

Associated with shipbuilding, roofing, plumbing

"Ivory white" calcified, supradiaphragmatic and pleural plaques are pathognomonic of asbestosis.

Associated with higher incidence of lung cancer (bronchogenic carcinoma > mesothelioma)

Affects lower lobes

Asbestos (ferruginous) bodes are golden-brown fusiform rods resembling dumbbells, found in alveolar sputum

14

Berylliosis

A pneumoconiosis

Associated with exposure to beryllium in aerospace and manufacturing industries

Granulomatous on histology and therefore occasionally responsive to steroids

Affects upper lobes

15

Coal workers' pneumoconiosis

A pneumoconiosis

Prolonged coal dust exposure leads to macrophages laden with carbon leading to inflammation and fibrosis

AKA Black Lung Disease

Affects upper lobes

Anthracosis - asymptomatic condition found in many urban dwellers exposed to sooty air

16

Silicosis

A pneumoconiosis

Associated with foundries, sandblasting, mines.

Macrophages respond to silica and release fibrinogenic factors, leading to fibrosis

It is thought that silica disrupt phagolysosomes and impair macrophages, increasing susceptibility to TB.

Also higher risk of bronchogenic carcinoma

Affects upper lobes

"eggshell" calcification of hilar lymph nodes.

Asbestos is from the roof (was common in insulation) but affects the base (lower lobes)

Silica and coal are from the base (earth) and affect the roof (upper lobes)

17

Physical findings for Pleural Effusion

Decreased breath sounds
Dull to percussion
Decreased fremitus
No tracheal deviation or away from side of lesion (if large)

18

Atelectasis (bronchial obstruction) on physical exam

Decreased breath sounds
Dull to percussion
Decreased fremitus
Tracheal deviation away from side of lesion

19

Simple pneumothorax on physical exam

Decreased breath sounds
Hyperresonant
Decreased fremitus
No tracheal deviation

20

Tension pneumothorax on physical exam

Decreased breath sounds
Hyperresonant
Decreased fremitus
Tracheal deviation away from side of lesion

21

Consolidation (lobar pneumonia, PE) on physical exam

Bronchial breath sounds; late inspiratory crackles
Dull to percussion
Increased fremitus
No tracheal deviation

22

Lobar pneumonia

Organisms:

Strep pneumo (#1)
Legionella
Klebsiella

Features:

Intra-alveolar exudate leads to consolidation

May involve either lobe or lung

23

Bronchopneumonia

Organisms:

Strep pneumo
Staph aureus
H flu
Klebsiella

Features:

Acute inflammatory infiltrates from bronchioles into adjacent alveoli

Patchy distribution involving 1 or more lobes

24

Interstitial (atypical) pneumonia

Organisms:

Viruses (influenza, CMV, RSV, adenoviruses)

Mycoplasma
Legionella
Chlamydia

Features:

Diffuse patchy inflammation localized to interstitial areas at alveolar walls; diffuse distribution involving at least 1 lobe

Generally follows a more indolent course ("walking" pneumonia)

25

Small cell (oat cell) carcinoma

Lung cancer

Central location

Can be undifferentiated to very aggressive.

May produce ACTH (Cushing syndrome), SIADH, or antibodies against presynaptic Ca channels (Lambert-Eaton myasthenic syndrome) or neurons (paraneoplastic myelitis/encephalitis). Amplification of myc oncogenes common. Inoperable; treat with chemotherapy

Histology:

Neoplasm of neuroendocrine Kulchitsky cells (small dark blue cells)

Chromogranin A (+)

26

Adenocarcinoma

A non-small cell lung cancer

Peripheral location

Most common lung cancer in nonsmokers and overall (except for metastases). Activation mutations include KRAS, EGFR, and ALK. Associated with hypertrophic osteoarthropathy (clubbing)

Bronchioloalveolar subtype (adenocarcinoma in situ): CXR often shows hazy infiltrates similar to pneumonia; excellent prognosis

Histology :

- Glandular pattern on histology, often stains mucin (+)
- Bronchoalveolar subtype: grows along alveolar septa leading to apparent thickening of alveolar walls

27

Squamous cell carcinoma

A non-small cell lung cancer

Central location

Hilar mass arising from bronchus; cavitation; cigarettes; hypercalcemia (produces PTHrP)

Histo:

Keratin pearls and intercellular bridges

28

Large cell carcinoma

A non-small cell lung cancer

Peripheral location

Highly anaplastic undifferentiated tumor; poor prognosis. Less responsive to chemo; removed surgically

Histo:

Pleomorphic giant cells. Can secrete B-hCG

29

Bronchial carcinoid tumor

A non-small cell lung cancer

No lung location

Excellent prognosis; metastasis rare.

Symptoms usually due to mass effect; occasionally carcinoid syndrome (5-HT secretion leads to flushing, diarrhea, wheezing)

Histo:

Nests of neuroendocrine cells; chromagranin A (+)