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Flashcards in Pulmonary Deck (77):
1

Conducting vs respiratory zones

Conducting zone
-large and small airways, as get to smaller airways, have more in parallel and thus less resistance
-anatomic dead space - no gas exchange
-cartilage, goblet cells, pseudostratified columnar epithelium to beginning of terminal bronchioles
-airway smooth muscle cells through terminal bronchioles

Respiratory zone
-respiratory bronchioles, alveolar ducts, and alveoli
-site of gas exchange
-cuboidal epithelium in respiratory bronchioles, simple squamous in alveolar ducts

2

Type I and type II pneumocytes

Type 1: Make up 97% of alveolar surfaces, squamous
Type 2: secrete surfactant, serve as precursors to type 1

3

Club cells

nonciliated, cuboidal cells with secretory granules that secrete a component of surfactant

4

Surfactant

secreted by type II pneumocytes and club cells; made up of lecithins including dipalmitoylphophatidylcholine. Synthesis begins at week 26, mature levels at week 35. Lecithin : sphingomyelin ratio over 2 indicates fetal lung maturity

5

Aspiration locations

When upright: lower portion of R inf lobe
When supine: sup portion of R inf lobe

6

Relationship between pulmonary artery and brochus

Righ: pulm artery anterior to main bronchus
Left: pum artery superior to main bronchus

7

Structures perforating diaphragm

T8: IVC
T10: esophagus and vagus n
T12: aorta

8

Functional residual capacity

residual volume plus expiratory reserve volume (volume of gas in lungs after normal expiration

9

Physiologic dead space

=anatomic dead space of conducting airways + alveolar dead space (most is in apex)

10

Minute ventilation vs alveolar ventilation

Minute ventilation=Total volume of gas entering lungs per minute
=Vt x RR

Alveolar ventilation=Volume of gas per unit time reaching alveoli

11

Intrapleural pressure

Negative at FRC to prevent pneumothorax

12

Compliance

Change in lung volume for given change in pressure. Decreased in pulmonary fibrosis, pneumonia, pulmonary edema. Increased in emphysema, aging.

13

Methemoglobinemia

Oxidized form of Hb with increased affinity for cyanide, decreased affinity for O2

Presents with cyanosis and chocolate-colored blood

Treated with methylene blue

Can induce methemoglobinemia with nitrites to treat cyanide poisoning

14

Perfusion vs diffusion limited

Perfusion limited: Gas equilibrates early along length of capillary; diffusion increased only if blood flow increased; case in normal lung

Diffusion limited: Gas does not equilibrate by time blood reaches end of capillary; seen in emphysema and pulmonary fibrosis

15

Alveolar gas equation

PAo2 = PIo2 - PaCO2/R

16

Causes of hypoxemia

Normal A-a gradient: high altituide, hypoventilation

Increased A-a gradient: V/Q mismatch, diffusion limitation, right to left shunt

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V/Q mismatch in normal lung

V/Q high at apex: wasted ventilation
V/Q low at base: wasted perfusion
both ventilation and perfusion greater at base than apex
V/Q approaches 1 with exercise due to vasodilation of apical capillaries

18

Pathology of V/Q

V/Q=0 airway obstruction (shunt), 100% O2 does not improve

V/Q=infinity blood flow obstruction, 100% O2 improves PaO2

19

Transport of CO2

90% as HCO3-
5% as HbCO2
5% as dissolved CO2

20

Vichow triad

1) stasis
2) hypercoagulability
3) endothelial damage: exposed collagen triggers clotting cascade

21

Homan sign

dorsiflexion of foot causes calf pain; sign of DVT

22

Lines of Zahn in PE

Interdigitated areas of pink and red found in thrombi that occur prior to death

23

Classic triad of fat emboli

Hypoxemia + neurologic abnormalities + petechial rash

24

Amniotic fluid emboli - complication

Can lead to DIC, especially postpartum

25

Air emboli

Nitrogen bubbles precipitate in ascending divers. Treated with hyperbaric O2

26

PFTs of obstructive lung disease

Decreased FEV1 and decreased FVC with decreased FEV1/FVC ratio (hallmark)

27

Chronic bronchitis

Path: hyperplasia of mucus secreting glands

Clinical: productive cough for over 3 mos per year for over 2 years. Wheezes, crackles, cyanosis, hypercapnea, secondary polycythemia

28

Emphysema - two forms

Centriacinar associated with smoking
Panacrinar associated with alpha1 antitrypsin def

29

Emphysema findings

Increased elastase activity leading to loss of elastic fibers and increased compliance/decreased recoil

30

Pathologic findings of asthma

Smooth muscle hypertrophy
Curschmann spirals: shed epithelium forms mucus plugs
Charcot-Leyden crystals: eosinophilic, hexagonal, double pointed crystals from breakdown of eosinophils in sputum

31

Sarcoidosis findings

Bilateral hilar lymphadenopathy, noncaseating granulomas, increased ACE, increased Ca++

32

Hypersensitivity pneumonitis

Mixed type III/IV hypersensitivity. Dyspnea, cough, chest tightness, headache. Classically in farmers and those exposed to birds

33

Asbestosis

Exposure: shipbuilding, roofing, plumbing

Pathology: ivory white calcified supradiaphragmatic and pleural plaques. Golden brown rods in alveolar septum.

Presentation: restrictive lung disease. Risk of cor pulmonale. Risk of lung cancer (bronchogenic carcinoma more than mesothelioma)

34

Berylliosis

Exposure: aerospace and manufacturing industries

Pathology: granulomas in upper lobes

Presentation: restrictive lung disease

35

Coal workers pneumoconiosis

Exposure: prolonged coal dust exposure

Pathology: Macrophages laden with carbon, inflammation, fibrosis in upper lobes

Presentation: restirctive lung disease

36

Silicosis

Exposure: foundries, sandblasting, mines

Pathology: Macrophages release fibrogenic factors in response to silica. Eggshell calcifcation of hilar lymph nodes. Effects upper lobes.

Presentation: Restrictive lung disease. Increased risk for bronchogenic carcinoma

37

Neonatal respiratory distress syndrome

Pathophysiology: surfactant deficiency causes increased surface tension and alveolar collapse

Imaging: ground glass appearance of lung fields

Treatment: Maternal steroids before birth, artificial surfactant for infant

Complications: PDA due to persistent low O2. Retinopathy, intraventricular hemorrhage, and bronchopulmonary dysplasia due to supplemental O2

38

ARDS

Presentation: Acute onset resp failure with bilateral lung opacities and decreased PaO2/FiO2 in absence of HF

Pathology: Diffuse alveolar damage results in increased alveolar capillary permeability and protein leak into alveoli. Causes noncardiogenic pulmonary edema with normal PCWP. Formation of intra-alveolar hyaline membranes.

Treatment: mechanical ventilation with low tidal volume

39

Drugs that cause pulmonary hypertension

Amphetamines, cocaine

40

Pathology of pulmonary hypertension

pulmonary artery pressure greater than 25 mmHg at rest

Arteriolosclerosis, medial hypertrophy, intimal fibrosis of pulmonary arteries

41

Tracheal deviation in different respiratory conditions

pleural effusion: none or away from side of lesion
atelectasis: toward side of lesion
tension pneumo: away from side of lesion
simple pneumo: none

42

Types of pleural effusion

Transudate: due to disruption of starling forces (increased hydrostatic pressure, decreased oncotic pressure) due to HF, nephrotic syndrome, hepatic cirrhosis. Low protein

Exudate: High protein. Due to malignancy, pneumonia, collagen vascular disease, trauma

Lymphatic: High TGs. Due to thoracic duct injury by trauma or malignancy

43

Types of pneumothorax

Primary spontaneous: rupture of apical blebs or cysts in tall thin young male

Secondary spontaneous: due to diseased lung or high pressure mechanical vent

Traumatic: blunt or penetrating trauma

Tension: Air enters pleural space but can't get out. Causes trachea to deviate away from affected lung

44

Lobar pneumonia

Organisms: S pneumo, Legionella, Klebsiella

Pathology: consolidation due to exudate, involves entire lobe or lung

45

Bronchopneumonia

Organisms: S pneumo, S aureus, H flu, Klebsiella

Pathology: inflammation from bronchioles into adjacent alveoli, patchy distribution

46

Interstitial pneumonia

Organisms: viruses, mycoplasma, legionella, chlamydia

Pathology: diffuse patchy involvement involving interstial areas

47

Lung abscesses

Clinical: Classically seen in patients with loss of consciousness and aspiration of oropharyngeal contents or bronchial obstruction

Pathology: Local collection of pus in parenchyma. Due to anaerobes

Imaging: Air-fluid levels

Treatment: Clindamycin

48

Pancoast tumor

Carcinoma in apex of lung. Can invade cervical sympathetic chain and cause Horner syndrome, SVC syndrome, sensorimotor defects, hoarsness

49

SVC syndrome

Obstruction of SVC by malignancy or thrombosis preventing blood drainage from head, neck, and upper extremities. Causes facial plethora, JVD, and edema. Can raise intracranial pressure if obstruction severe.

50

Sites of metastasis for lung cancers

Adrenals, brain, bone, liver

51

Cancers that metastasize to lung

Breast, colon, prostate, bladder

52

Small cell carcinoma of lung

Location: central

Pathology: Undifferentiated neuroendocrine cells that appear as small dark blue cells. Chromogranin A+, amplificiation of myc genes

Clinical: Very aggressive. Can made ACTH, cause SIADH, cause myasthenic syndrome, cause paraneoplastic encephtalitis

53

Adenocarcinoma of lung

Location: peripheral

Clinical: most common lung cancer in nonsmokers, and overall. Clubbing.

Pathology: mutations in KRAS, EGFR, ALK. Glandular pattern. Mucin +

54

Squamous cell carcinoma of lung

Location: central

Clinical: can cause hypercalcemia through a paraneoplastic syndrome

Pathology: Hilar mass, cavitation, keratin pearls

55

Large cell carcinoma of lung

Location: peripheral

Clinical: Poor prognosis

Pathology: Highly anaplastic and undifferentiated, pleomorphic giant cells, can secrete beta hcG

56

Bronchial carcinoid tumor

Pathology: neuroendocrine cell nests; chromogranin A +

Clinical: escellent prognosis, presents with symptoms of mass effect, occasionally cuases carcinoid syndrome

57

meconium ileus

obstruction of distal ileum by dehydrated meconium. Most commonly cuased by cystic fibrosis. Often is the presenting symptom at birth of CF.

58

Influenza vaccine

Inactivated vaccine: Induce antibodies against hemagglutinin antigen which inhiibin bindings ot hemagglutinin to host cell receptors, prevneting virus from entering cells.q

59

Minute ventilation vs alveolar ventilation

Minute ventilation is total volume of new air that enters resp pathways per minute

Alveolar ventilation is only volume of new air reaching gas exchange areas per minute - doesn't include dead space

60

piriform recess

Cavities on either side of laryngeal orifice. During swallowing, food diverted into piriform recesses and then into esophagus by epiglottis. Food can get stuck in it and damage the internal laryngeal nerve, which serves as the afferent limb of the cough reflex

61

DHR flow cytometry

Tests for neutrophil superoxide production to diagnose CGD. Preferred to NBT testing.

62

First vs second generation H1 blockers

First gen: end in "ine" or "ate" - diphenhydramine, dimenhydrinate, chlorpheniramine

Second gen: end in "adine" - loratadine, fexofenadine, desloratadine, cetirizine

63

N-acetylcysteine

Mucolytic agent used to loosen mucus plugs in CF patients by disrupting disulfide bonds.

Also is antidote for acetaminophen OD

64

Dextromethorphan

Synthetic codeine. Antagonizes NMDA glutamate receptors

65

Nasal decongestants

Names: Pseudophedrine, phenylephrine

MOA: alpha1 agonists, constrict nasal vessels to reduce edema and congestion

ADRs: HTN, CNS stimulation/anxiety

66

Bosentan

MOA: endothelin-1 receptor antagonist - decreases pulmonary vascular resistance

Use: pulm htn

ADRs: hepatotoxicity

67

Sildenafil

MOA: Inhibits PDE-5 leading to vasodilation

Use:pulm HTN, ED

68

Prostacyclin agonists

Names: epoprostenol, iloprost

MOA: vasodilatory effect, inhibits platelet aggregation

ADRs: flushing, jaw pain

Use: pulm htn

69

Ipratropium

MOA: muscarinic antagonist - prevents bronchoconstriction

Use: asthma, COPD; tiotropium is long acting form

70

Anti-leukotriene agents

Montelukast and zafirlukast: block leukotriene receptors, good for aspirin-induced asthma

Zileuton: 5-lipoxygenase pathway inhibitor, blocks conversion of AA to leukotrienes

71

Omalizumab

monoclonal anti-IgE antibody

used in allergic asthma resistant to steroids and B2 agonists

72

theophylline

MOA: inhibits phosphodiesterase, increasing cAMP and causing bronchodilation

Use: narrow therapeutic index limits use for asthma

73

Metacholine

MOA: M3 agonist

Use: metacholine challenge to diagnose asthma

74

Cryptococcus neoformans

Budding yeast with thick capsule. Opportunistic pathogen. Most commonly causes meningoencephalitis. Lung infection usually occurs first but is usually asymptomatic

75

Normal A-a gradient

Less than 10-15 mmHg

76

Pancoast syndrome

Caused by tumor at lung apex, often in superior sulcus.

Presents with shoulder pain, Horner syndrome, spinal cord compression

77

Fat embolism syndrome

Acute onset neurologic abnormalities, hypoxemia, petechial rash