Pathology Of Obstructive Lung Diseases Flashcards

1
Q

Obstructive airway board definition

A

Characterized by an increase in resistance to air flow due to obstructions so air has issues getting out.

  • TLC increased
  • RV increased
  • FRC increased
  • FVC normal
  • FEV1 significantly decreased
  • FEV1/FVC decreased

COPD specific obstructive issues are irreversible obstructions
- asthma is reversible

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2
Q

Specific types of obstructive lung diseases

A

Asthma
- hyper responsiveness of bronchi

Chronic bronchitis
- large air way inflammation

Emphysema
- alveolar wall destructions

Bronchiectasis

Bronchiolitis

emphysema and chronic bronchitis often is often seen paired with each other

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3
Q

Emphysema

A

Permanent enlargement of the air spacers distal to terminal bronchioles w/ destruction of alveolar walls
- causes destruction of elastic tissue which causes bronchioles to collapse during expiration

There is no significant fibrosis

Two most common types of emphysema

  • centriacinar (MOST COMMON)
  • panacinar

Morphology shows loss of overalls tissues w/ NO FIBROSIS

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4
Q

Centriacinar emphysema

A

Proximal parts of the acini of the respiratory bronchioles are affected
- alveoli are spared

Lesions are more common in the upper lobes usually in apical segments

MOST common, especially in cigarette smokers

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5
Q

Panacinar emphysema

A

Distal Acini are enlarged
- alveoli are affected

Lesions are more common in the lower lung zones and more common in alpha-1 antitrypsin deficency

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6
Q

3 primary factors the influence the development of all types of emphysema

A

1) Oxidative stress and increased apoptosis/senescence
- often seen in smoking and inhaling pollutants

2) inflammatory cells and release of inflammatory mediators
- often seen in chronic infections

3) protease-antiprotease imbalance
- deficency in anti-protease levels and often seen in congenital alpha-1 antitrypsin deficiencies

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7
Q

Alpha-1 antitrypsin deficency quick description

A

Deficency in anti-trypsin production

  • function is to inhibit proteases
  • causes decreased protease inhibitors which causes chronic inflammation

1% of all patients w/ emphysema have this defect
- this 1% almost always develops panacinar emphysema type

Located on Pi locus on chromosome 14 w/ Z Allele being the bad allele on the gene

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8
Q

Severe emphysema leads to what?

A

Hypoxia-induced pulmonary vascular spasms and loss of pulmonary capillary surface area
- leads to pulmonary HTN and cor pulmonale

cor pulmonale or respiratory failure are the end stage emphysema causes of death

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9
Q

Chronic bronchitis

A

Clinically defined as the presence of a persistent, productive cough for at least 3 consecutive months in at least 2 consecutive years

Presence of hypersecretion of mucus is the distinctive feature in chronic bronchitis and is caused by environmental irritants (causes the consistent coughing)
- also produces hypertrophy of mucous glands, increases in mucus secreting goblet cells numbers in bronchi/bronchioles

Is common among cigarette smokers and urban dwellers in smoggy cities

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10
Q

How is airflow obstructed in chronic bronchitis

A

Two main causes (although only #1 is required)

1) mucous plugging of the bronchi and bronchiole lumen

2) coexistence emphysema
- produces severe if present

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11
Q

Chronic bronchitis morphology

A

Diagnostic feature is enlargement of mucus secreting glands.
- assessed by the ratio of thickness of the gland: bronchial wall thickness

Reid index calculates this value and any index above 0.4 is chronic bronchitis

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12
Q

Chronic bronchitis clinical features

A

Signs/symptoms

  • productive severe coughing
  • sometimes develops COPD w/ significant cyanosis/hypercapnia/hypoxemia
  • leads to pulmonary HTN, cardiac failure and recurrent URI’s if untreated
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13
Q

Bronchiectasis

A

Permanent dilation of the bronchi/bronchioles caused by destruction of smooth muscles and support elastic tissues
- typically results from chronic necrotizing infections

  • is not a primary disorder and is always secondary to persistent infections*

Produces similar coughing to chronic bronchitis except wayyy more sputum

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14
Q

Cystic fibrosis

A

Disorder of epithelial ion transport (choiride ions specifically) CFTR genes and proteins are affected.

  • affects respiratory, GI and reproductive tracts
  • also produces super salty sweat glands

Multiple different mutations can lead to CF

  • the most common and lethal genetic disease that affects white people though (1:20 carrier frequency)
  • is autosomal recessive though (1:2500 incidence)

Leads to dehydrated thick mucus that cannot be transported properly and blocks airways and pancreatic ducts

  • leads to the following tow most important clinical manifestations found in CF:
    1) recurrent URIs
    2) pancreatic insufficiency
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15
Q

Cystic fibrosis pathogenesis

A

In sweat glands

  • chloride ions do not leave the sweat they cant enter the sweat glands
  • produces super salty sweat

In all other epithelium

  • chloride ions cant get out of the epithelial cells
  • results in water entering cells and dehydrating mucus making it hard/impossible for cillia to move it.
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16
Q

What is the most common mutation in CF?

A

Deletion of three nucleotides that code for phenylalanine (Phe) @ amino acid position 508

  • causes misfolding and complete loss of CFTR
  • 70% of all CF cases
  • is autosomal recessive
17
Q

What is the most serious complications of CF?

A

Pulmonary changes are the most severe

  • result in development of lung abscesses and super imposed infections into the lungs
  • hypertrophy and hyperplasia of the goblet cells, also leads to bronchiectasis
18
Q

What are the 3 most common organisms to cause infections in CF?

A

Staph aureus

Haemophilus influenza

Pseudomonas aeruginosa
- most deadly of the three and hardest to cure

  • NOTE: while not common, rates of Burkholderia cepacia are increasing slowly every year*
19
Q

Pancreatic insufficiency in CF

A

Found in 85-90% of all cases

Milder cases
- accumulations of mucus in small ducts causes dilation in exocrine glands

Advanced cases

  • ducts are completely plugged and causes atrophy of exocrine glands as well as impaired fat absorption and Vit. A deficiency
  • more common, especially in the F508 mutant change
20
Q

Liver involvement in CF

A

Similar patterns to the pancreas

- blocks ducts leadings to fatty liver and cirrhosis of the liver (similar to drinking)

21
Q

Cardiorespiratory complications of CF

A

Chronic coughing

Persistent URIs

Develops COPD

Devolpment cor pulmonale
- most common cause of death in CF patients

80% of patients with classic CF harbor P. Aeruginosa in their lung mucus

22
Q

Primary ciliary dyskinesia (kartagener syndrome)

A

Autosomal recessive syndrome that is super rare

  • results in ciliary motor protein (dysin) defects preventing mucocillary movement
  • causes similar affects to CF

Half of patients develop kartagener syndrome which is the following four issues combined:

1) situs inversus
2) bronchiectasis
3) sinusitis
4) infertility for males

23
Q

Bronchiectasis clincal features

A

Caused by blockage from lower bronchi/bronchioles (dilates them 4x as large as normal)

Mild Signs/symptoms:

  • severe persistent cough w/ Sputum
  • dyspnea
  • rhinposinustis
  • hemoptysis

Severe signs/symptoms:

  • hypoxemia
  • hypercapnia
  • pulmonary HTN
  • cor pulmonale
24
Q

Asthma

A

Chronic inflammatory disorder of the airways that causes recurrent episodes of wheezing, breathlessness and chest tightness and coughing

Incidence is slowly increasing every year

  • is a type 1 hypersensitivity
  • also acute and chronic airway inflammation from outside sources can lead to de novo asthma

Hallmarks include:

  • intermittent reversible airway obstructions
  • chronic bronchial inflammation w/ high eosinophils
  • bronchial SMC hypertrophy and hyperreactivity w/ increased mucus secretions
25
Q

Classic atopic asthma

A

Associated with excessive type 2 Helper T cell activations

  • results in IL-4 production: increases IgE production
  • results in IL-5 production: activates eosinophils
  • results in IL-13 production: stimulates mucus production

MOST COMMON type

Very genetic based and is often preceded by allergic rhinitis or eczema

Is a type 1 hypersensativity reaction

26
Q

Early phase vs late phase activations in asthma

A

Early phase:

  • bronchoconstriction
  • increased mucus production
  • vasodilation
  • caused by release of histamine, prostaglandin D2 and leukotrienes and reflex pathways

Late phase:

  • inflammation
  • eosinophil and leukocyte recruitment
  • caused by TH2 cells and resident immune cells in the airways
27
Q

Non-atopic asthma

A

No allergen sensitization and very little evidence suggesting genetic base

Usually develops secondary to respiratory infections from virus
- is hypothesized that virus-induced inflammation lowers threshold of subepithelial vagal receptors to irritants (making them hyper reactive)

28
Q

Drug-induced aspirin

A

Often caused by aspirin

Presents with recurrent rhinitis, nasal polyps urticaria and bronchospasms

Idiopathic epidemiology but is hypothesized to be an issue in prostaglandin metabolism from inhibition of COX-1/2 from aspirin