Asthma

Question 1

How do elastic fibres affect the bronchial wall in inhalation and exhalation?

Answer 1

When you breathe in, the bronchial walls open up to let air in and the elastic fibres pull them open. On exhalation the bronchial walls collapse as the elastic fibres relax. This becomes an issues when there’s a lot of mucous or inflammation in the airways like in asthma, copd or cystic fibrosis.

Question 2

In chronic obstructive lung dx, is it a problem of getting air in or air out?

Answer 2

More of a problem of getting air out as the airways collapse. Air is then trapped in the lungs and that makes it more difficult to take the next breath.

Question 3

How do people compensate for this difficulty breathing?

Answer 3

Accessory muscle use. The lungs expand - increased lung volume and this causes hyperinflation of the alveoli. Ribs are farther apart and diaphragm is more flat.

Question 4

What does FVC stand for? What is it’s significance?

Answer 4

Forced Vital Capacity. The amount of air that can be forcibly exhaled from the lungs.

Question 5

What is FEV1? What is it’s significance?

Answer 5

The amount of air that is blown out of the lungs in the first second.

Question 6

What happens to FVC and FEV1 with chronic obstructive lung disease?

Answer 6

They are both decreased. A normal FEV1/FVC is 90% and someone with lung dx may have less then 70%.

Question 7

How does chronic obstructive lung dx also affect RR?

Answer 7

RR is slowed because it’s harder to inhale and exhale.

Question 8

What part of the lung is affected by asthma?

Answer 8

Small bronchi and bronchioles. Airways have exaggerated tendency to narrow in response to triggers making them hyperresponsive.

Question 9

What happens to asthma that isn’t well controlled?

Answer 9

The airways remodel and become permanently thickened.

Question 10

What causes asthma?

Answer 10

Genetic predisposition and environmental factors like allergens, polution, cigarette smoke, child resp infections, and occupational exposures.

Question 11

What are some triggers for asthma?

Answer 11

allergens, cigarettes, virus, exercise, cold dry air, drugs (nsaids and beta blockers), strong odours, stress, air pollution, irritants, gerd, food additives and preservatives, hormone changes

Question 12

What are the two types of asthma?

Answer 12

1) Allergic (exposure to allergen)/Extrinsic
2) Non allergic (initiated by airway irritant)/Intrinsic

People can have both forms

Question 13

What’s different about people with allergic asthma?

Answer 13

They have a genetic predosiposition to devel IgE response to allergens (atopy).

Question 14

What can you find in someone’s blood work with allergic asthma?

Answer 14

Elevated IgE levels.

Question 15

What happens in an allergic asthma attack?

Answer 15

Someone gets exposed to an allergen which triggers a lot of allergen specific IgE to be made. IgE that doesn’t get exposed to allergen binds to airway mast cells (airway sensitization). There then is an imbalance of T helper 2 cells to T helper 1 cells.

Question 16

What triggers non allergic asthma?

Answer 16

Viral resp infections or exposure to bronchial irritants

Question 17

What happens in a non-allergic asthma with viral trigger?

Answer 17

Viral infxncauses damage to resp epithelium causing inflammation. Airways become sensitive to other triggers.

Question 18

What happens in non-allergic asthma that’s exercise induced?

Answer 18

Loss of heat and water from airways causes irritation and inflammation. This is even worse in cold, dry weather. The attack stops when the exercise stops and airways are less dilated from sympathetic nervous response. Goes away after 60 mins usually.

Question 19

How does aspirin and NSAIDS induce non allergic asthma?

Answer 19

These drugs block COX enzyme and prostaglandin synthesis which causes a relative increase in leukotriene synthesis which causes bronchoconstriction.

Question 20

What happens when inhaled irritants cause asthma?

Answer 20

Airways get inflammed and stimulate irritant receptors causing bronchoconstriction. Meant to be a protective response. Irritant receptors cause reflex parasympathetic nervous response which causes acute bronchoconstriction.

Question 21

An allergic asthma is divided in to two parts - acute asthmatic response (first response) and the late asthmatic response. What happens in the early response?

Answer 21

Allergens activate mast cells and therefore T helper 2 cells on the mucosal surface in the airways walls. Mast cells release histamine and chemotactic factors AND make prostaglandins and leukotrienes (which make a slower and more prolonged response). T helper cells release cytokines that contribute to inflammation.

Question 22

What does the early response look like in the airways?

Answer 22

Muscles contract and constrict in the airways, the airways swell, and there is increased mucus production. Can be tx. with rescue inhalaer/bronchodilator. Usually a short acting Beta 2 agonist which relaxes bronchial smooth muscle and increases airflow.

Question 23

What happens in the late response? When does that take place?

Answer 23

4-12 hours after initial attack and can last for a few days. There is prolonged action of prostaglandins and leukotrienes, eosinophils are recruited by chemotactic factors released by T helper 2 cells and mast cells. Parasympathetic reflexes are activated (think swelling of bronchioles)

Question 24

What role do eosinophils play in an asthma attack?

Answer 24

They’re a WBC that release proteins that is usually toxic to parasites. Eosinophils cause epithelial damage and inflammation. The cells that are shed are called creola bodies and those can be found in sputum of asthmatics.

Question 25

Why does the parasympathetic NS affect asthmatics?

Answer 25

When there’s epithelial damage, it exposes subepithelial sensory nerve endings which activates the parasympathetic/vagal reflexes causing MORE bronchoconstriction and mucus secretion. This is a long lived response.

Question 26

What happens in airway remodelling?

Answer 26

The damage to epithelial cells stimulates collagen deposition and fibrosis. Airway smooth muscle layer thickens (hypertrophy) and mucous glands hypertrophy and goblet cells replace los epithelial cells which make even more mucous. This leands to permanent obstruction and persistent symptoms.

Question 27

What are some symptoms of a mild attack?

Answer 27

Mild wheezing (narrowed airways), cough (irritant receptor stimulation from inflammation and mucus accumulation), chest tightness (due to air trapping and hyperinflation) and slight tachypnea (but prolonged exhalation)

Question 28

What are some symptoms of a severe attack?

Answer 28

Loud wheezing, severe dyspnea, laboured breathing and accessory muscle use, tachypnea and tachycardia, and anxiety.

Question 29

Your pt reports having continuous SOB in the day time, and frequent SOB at night time. You do their PEF or FEV1 and it’s less than 60. What severity of asthma do they have?

Answer 29

Severe persistent asthma. Step 4.

Question 30

Your pt says they are SOB and coughing every day, and feel SOB at least 2x a week. You do their PEF/FEV1 and it’s 65. What does that mean?

Answer 30

Moderate persistent asthma. Step 3.

Question 31

Your patient says they’re almost never SOB except when they’re sick with a cold. You do their PEF/FEV1, and it’s 80 what does that mean?

Answer 31

Mild, intermittent. Step 1.

Question 32

Your patient says their SOB affects them 2 times a week in the day time, and maybe 1 or 2 times a month at night. What level of asthma do they have?

Answer 32

Step 2 - mild persistent. Their PEF/FEV1 would be about 80.