When things go wrong in the respiratory system Flashcards

1
Q

What do you use to measure airway resistance?

A

Forced expiratory volume in 1 sec (FEV1) by spirometry

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2
Q

What is FEV1 usually?

A

FEV1 is normally 80% of vital capacity (forced exhalation is usually about 80% of total exhalation)

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3
Q

What are the main features of Chronic Obstructive Pulmonary diseases (COPDs)?

A
  • Narrowing of airways -> increased airway resistance
  • Elastic recoil of lungs lost -> decreased outflow pressure
  • Both lead to decreased FEV1
  • Increased residual volume (RV) (air remaining in lungs after fully exhaled) -> appearance of chest over-inflation
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4
Q

What are the main COPD diseases?

A
  • Chronic bronchitis – narrowing

- Emphysema – recoil

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5
Q

What is Chronic Bronchitis, how do you define it and what is it usually due to?

A
  • Inflammation of the bronchi – mucus hypersecretion
  • Due to: smoking (80%), environmental irritants
  • Lasts: at least 3 consecutive months in 2 consecutive years
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6
Q

What happens in Chronic Bronchitis?

A
  • Irritants cause inflammation in bronchi
  • Abnormal mucus secretion
  • Plugs airways
  • Prone to infection
  • Further inflammation
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7
Q

What is the result of chronic bronchitis?

A

 Airway obstruction
 Shortness of breath/ wheezing
 Chest pain, chronic (productive – sputum) cough

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8
Q

What is the treatment for chronic bronchitis?

A

 Stop smoking
 Bronchodilators
 Antibiotics

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9
Q

What is Acute bronchitis?

A
  • Due to bacteria/ virus

- Lasts days/ weeks

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10
Q

What happens in Emphysema?

A
  • Smoking -> neutrophils and macrophages release elastase -> elastase destroys alveolar walls -> emphysema
  • In healthy tissues we have anti-proteases that neutralise elastase (alpha1 antitrypsin) but not in emphysema
  • Genetic alpha 1 antitrypsin deficiency also leads to emphysema (2% COPD patients)
  • See increased compliance significantly ABOVE normal
  • Increased RV (residual volume) -> increased FRC (functional residual capacity): chronically over-inflated lung
  • Air gets trapped in lungs
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11
Q

What are the symptoms of emphysema?

A

 Shortness of breath on exertion
 Hyperventilation
 Expanded chest

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12
Q

What is used to treat emphysema?

A
  • Enzyme supplements in alpha 1 antitrypsin deficiency
  • Supplemental O2 can be given
  • Lung transplant the best method of treatment
  • but loss of alveoli is permanent and irreversible
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13
Q

What are the symptoms of asthma?

A

 Increased airway resistance:
 Bronchoconstriction
 Oedema of airway mucosa
 Mucus-secretion

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14
Q

What are the causes/ precipitating factors of asthma?

A
 Hypersensitivity reaction to allergens 
 Air pollution 
 Exercise and cold air 
 Emotional stress 
 Genetics?
 Conflicting evidence with causes
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15
Q

What is the mechanism of asthma?

A

Mast cell activation -> histamine and cytokine release -> oedema, mucus, smooth muscle contraction - bronchoconstriction

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16
Q

What is the treatment for asthma?

A

 Bronchodilators e.g. salbutamol (beta 2 adrenoceptor agonist)
 Anti-inflammatories

17
Q

What are the main restrictive lung disease disorders?

A
  • Fibrosis – development of excessive connective tissue

- Respiratory distress syndrome (IRDS, ARDS, SARS)

18
Q

What happens in restrictive lung disease?

A

Alveolar walls become rigid (lungs become rigid)

19
Q

What happens in acute restrictive lung disease?

A

Sepsis of severe trauma -> protein exudation -> oedema (thickening of walls)

20
Q

What happens in chronic restrictive lung disease

A

Industrial dust, drugs, rheumatism -> inflammation -> fibrosis (alveolar walls replaced by fibrotic tissue)

21
Q

What happens in fibrosis?

A

(development of excess connective tissue) – lungs stiffer:
- Alveoli replaced by fibrotic tissue -> DECREASED lung compliance
• Leads to ‘honeycomb lung’ where the lung is so stiff no air can be moved in or out

22
Q

What are the causes of fibrosis?

A
  • Inhaled environmental and occupational pollutants
  • Cigarette smoke
  • Autoimmune disease
23
Q

What is the treatment for fibrosis?

A

There isn’t one

24
Q

What type of respiratory tract infections can you get and give some examples?

A

• Upper respiratory tract infections
- Common but minor
- Average adult gets around 2-4 URTI/year
• Lower respiratory tract infections
- Less common but more serious
- E.g. bronchitis, pneumonia, tuberculosis

25
Q

What is Pneumonia and what is it caused by?

A
  • acute infection of the lung

- Caused by bacteria: Streptococcus pneumoniae, Staphylococcus aureus or Klebsiella pneumonaiae

26
Q

What happens in pneumonia?

A

It affects bronchi and alveoli -> inflammatory exudate fills alveoli -> lead to ‘consolidation’ (lung tissue becomes firm and airless)

27
Q

What is bronchopneumonia?

A

 Acute inflammation of the bronchi

 Often accompanied by inflammation in nearby lobules of lung

28
Q

What is lobar pneumonia?

A

 Intra-alveolar space affected

 Large area of lung affected

29
Q

What is Tuberculosis caused by?

A
  • Caused by inhalation of mycobacterium tuberculosis

 Highly contagious

30
Q

What is TB in it’s latent phase?

A

asymptomatic, non-infectious, granuloma in lung tissue

31
Q

What happens in the active phase of TB?

A
  • spreads to bronchioles and circulation (10% cases)
     Infection in alveoli -> replicate in alveolar macrophage (Ghon focus – site of primary infection)
     Initial infection – ineffective immune response
     Bacteria then move to lymph nodes (secondary inflammation)
     Collagen deposited around bacteria which can cause damage to the lymph nodes
     Lymph nodes erodes releasing bacteria
     Drainage into bronchioles and blood vessels
     Destruction of alveoli
32
Q

What is the treatment for TB?

A
  • Antibiotics

- difficult because of antibiotic resistance

33
Q

Give features of COVID-19

A
  • Similar to SARS- 1
  • Coronaviruses – coronaviridae family in the Nidovirales order
  • ‘Corona’ = crown-like spikes on the outer surface of the virus
  • 65-125 nm in diameter
  • Contain a single-stranded RNA (26 to 32 kilobases (kb) in length
  • Believed to be of zoonotic origin
34
Q

How is COVID-19 transmitted and what happens in the body?

A

 Primarily via direct contact or through droplets spread by coughing or sneezing
 Binding of a receptor expressed by host cells is the first step of viral infection and is then followed by fusion with the cell membrane
 Lung epithelial cells thought to be primary target
 Receptor = angiotensin – converting enzyme 2 (ACE2) receptor – most abundant in type 2 alveolar cells

35
Q

How many doses of the Pfizer vaccine are required for full immunity to COVID-19?

A

two doses

36
Q

In TB where may the bacteria colonize?

A

the respiratory passageways, the interstitial spaces, the alveoli or a combination of them

37
Q

What are symptoms of TB?

A

coughing and chest pain, fever, night sweats, fatigue and weight loss

38
Q

What happens in cystic fibrosis?

A

the respiratory mucosa produce dense, viscous mucus that cannot be transported by the respiratory defence system – the muscocilliary escalatory stops working leading to frequent infections. Mucus also blocks the smaller respiratory passageways making breathing difficult