PBL 8: Respiratory module by wardina dayana

nrwrdnadyna — 2021-08-25 07:58:00 UTC

ENCIK SHAFIQ, 35-Year-old
Diagnosed with Bronchial Asthma

Symptoms

nrwrdnadyna — 2021-08-25 07:59:37 UTC

3 months history non-productive cough [worse at night]
Wheezing
Shortness of Breath [Dyspnea]

Patient History

nrwrdnadyna — 2021-08-25 08:00:56 UTC

- No past medical history of hypertension and diabetes mellitus
- Not taking any medication and no drug allergy
- Family history: his father has allergic rhinitis and 2 of his brother have asthma
- Social history: he is non-smoker, works as a clerk in a law firm however, for past 3 months need to take frequent sick leave. He lives in a terrace house with his wife and recently adopted a cat.

Cough

nrwrdnadyna — 2021-08-25 08:02:47 UTC

- Cough is a sudden explosive expiration that helps clear the tracheabronchial tree of secretions and foreign bodies

1. Type of cough (duration)

Acute < 3 weeks
Sub-acute = 3- 8 weeks
Chronic > 8 weeks

2. Type of cough (expectoration)

Dry- No sputum production usually due to allergy or cold
Productive- Phlegm or sputum produced, due to diseases
Bovine- Non-explosive, seen in vagus nerve lesion
Whooping- Paroxysms of cough, post-tussive in pertussis infection
Brassy- Barking cough associated with croup

3. Common cause of cough

Asthma
Allergies
Pneumonia
Smoking
Bronchitis
Acid reflux
Medication

4. Mechanism of cough
1. Initiation phase= Irritation in the tracheobronchial tree-> Afferent impulses are carried via the vagus and glossopharyngeal nerve

2. Inspiration phase= Deep inspiration (2.5 to 3 litres of air)

3. Compression phase= Closure of epiglottis & vocal cords trapping the air within the lungs-> Forceful contraction of abdominal muscles-> Contraction of internal intercostal muscles-> Pressure in the lung rises above 300 cm H2O

4. Expulsion phase= Intrathoracic pressure becomes positive causing narrowing of the trachea, bronchi & bronchioles-> Vocal cords & epiglottis suddenly open-> Air is forced through the narrowed bronchi & trachea at velocities reaching 25000-28000 cm/sec or 75-100 miles/hour

BRONCHIAL ASTHMA

nrwrdnadyna — 2021-08-25 08:03:14 UTC

How allergic rhinitis cause Asthma (atopic triad)

nrwrdnadyna — 2021-08-25 08:03:52 UTC

- Allergic rhinitis as a risk factor for asthma. Patients with allergic rhinitis have 3x greater chance of developing asthma
- Patients with allergic rhinitis has high sensitivity towards environmental allergens similar to allergens in asthma
- Allergic rhinitis and asthma share a common pathogenesis (over-reaction of the immune system to an otherwise harmless allergen from the environment)
- These conditions have a genetic aspect at play and due to the similarities, they can incite those affected to develop one of the comorbid conditions, or all three (eczema, allergic rhinitis & asthma)
- Interestingly, the relief of rhinitis symptoms over time correlates with the improvement of asthma symptoms

Bronchial Asthma Management

nrwrdnadyna — 2021-08-25 08:04:41 UTC

1. Nebuliser

A device that can deliver high doses of medicines quickly and easily.
It works by changing liquid medicine into a fine mist. This mist can then be breathed in through a face mask or mouthpiece.
Nebulised salbutamol is introduced during asthma attack, but in higher dosage.
Salbutamol relieves symptoms by;
Acting as a functional antagonist to relax the airway.
Salbutamol promotes the production of intracellular cyclic adenosine monophosphate (cAMP),
cAMP enhances the binding of intracellular calcium to the cell membrane.
This action decreases the calcium concentration within cells and results in the relaxation of smooth muscle and bronchodilation.

2. Beclomethasone inhaler

Acts as a preventer inhaler.
Stops symptoms from developing.
To be used twice daily; even the symptoms are relieved, usage of beclomethasone must be continued daily to prevent symptoms from occuring again.

3. Salbutamol inhaler

Acts as a reliever inhaler.
Relieves symptoms when they occur.
Is used when needed, when the symptoms is present.

4. Asthma Action Plan
-A worksheet to guide and help En. Syafiq with his bronchial asthma management.

Pathophysiology of symptoms

nrwrdnadyna — 2021-08-25 08:06:02 UTC

1. non productive cough & worse at night and early morning
increase mucous production-> chemical and mechanical irritation of tracheobronchial tree-> bronchoconstriction-> stimulate cough receptor

2. wheezing (during expiration)
whistling sound of air travelling through a narrowed airway

3. dyspnea and tachypnea
airway obstruction-> increase CO2-> activate chemoreceptor-> stimulate accessory muscle for respiration-> forceful breathing-> increase breathing rate

Indication of the examination

nrwrdnadyna — 2021-08-25 08:07:03 UTC

Common indications for pulmonary function testing include:

Evaluation of respiratory complaints, such as cough and dyspnea.
Assessment and monitoring of disease severity and progression.
Monitoring for drug toxicity and efficacy.
Pre-operative assessment.
Evaluation of the effects of occupational or hazardous exposures

Interpretation of Spirometry

A mean (mid) value is used as the reference value when interpreting results but there are upper and lower levels of normal values; lung volumes of 80-120% of the predicted values are considered to be within normal limits

Abnormal results can be divided into obstructive and restrictive types

Obstructive lung disease

Air flow obstruction, whether acute or chronic, will reduce the FEV1 by increasing the airway resistance to expiratory flow. In chronic air flow obstruction, the chronic resistance can lead to chronic hyperinflation of the lungs. Due to premature closing of the airways on expiration, the FVC will also decrease but not as much as the FEV1. The FEV1/FVC will fall. The flow/volume graph has a concave appearance . The volume/time graph will show a line that rises slowly to reach its highest point, completing the full expiratory maneuver.

Restrictive lung disease
Caused by extrapulmonary conditions affecting movement of the chest wall (Box 1) and intrapulmonary conditions affecting lung elasticity (Box 2). Both affect inflation of the lungs and cause lung volumes to be reduced, but the calibre of the airways is unaffected. The volume/time graph has a shape similar to normal, but with a lower FEV1 and a lower FVC . The flow/volume graph has a squashed appearance .

4. Asthma Action Plan

2021-08-27 12:57:54 UTC

1. Nebuliser for asthma attack

2021-08-27 13:03:45 UTC

Definition

syahir_yhy — 2021-08-29 01:05:02 UTC

A chronic inflammatory airway disorder caused by airway hyperresponsiveness to a variety of stimuli that have recurrent episodes of wheezing, dyspnoea, cough, and chest tightness.

Types of BA

syahir_yhy — 2021-08-29 01:07:09 UTC

Examination for Bronchial Asthma

2021-08-29 01:11:15 UTC

The two most common lung function tests used to diagnose asthma:
1. spirometry
2. exhaled nitric oxide and challenge tests.

Spirometry : a simple breathing test that measures how much and how fast the patient can blow air out of their lungs. It is often used to determine the amount of airway obstruction the patient have

Types of Bronchial Asthma

syahir_yhy — 2021-08-29 01:14:11 UTC

1. Atopic-the most common type of asthma

a classic example of type 1 IgE-mediated hypersensitivity reaction
usually begins in childhood
triggered by environmental allergens such as dusts, pollens, roach or animal dander and foods
commonly with positive family history of atopic disorder like eczema, allergic rhinitis and allergic conjunctivitis

2(i). Non-atopic-immediate hypersensitivity evidence that is not associated with allergen sensitisation

negative skin prick test results
due to virus-induced inflammation of respiratory mucosa
adult onset
positive family history is less common
triggers include-respiratory viral infections (rhinovirus, parainfluenza, RSV), air pollutant (cigarette smoke, sulfur dioxide and ozone), cold and exercise.

2(ii) Drug-induced Asthma- several pharmacologic agents that provoke asthma

Aspirin-sensitive asthma and other NSAIDs
an uncommon yet fascinating type
occur in patients with recurrent rhinitis and nasal polyps
with small doses of aspirin, pt experiences asthmatic attacks and urticaria

2(iii) Occupational Asthma- stimulated by inhaled agents at work( fumes, organic and chemical dusts, gases and other chemicals)

inhaled agents act as irritants precipitating bronchospasm
may develop after single / repeat exposure
symptoms remits during off-work( weekends, holidays)

Phase 1

syahir_yhy — 2021-08-29 01:44:23 UTC

Phase 2

syahir_yhy — 2021-08-29 01:45:40 UTC

Vital signs

2021-08-29 02:49:27 UTC

Normal BP
Normal pulse rate
Normal temperature
High respiratory rate