Acute Severe Asthma Flashcards
What is an upper airway disease
This is a disease that affects anything from the nose to the larynx
What is meant by a lower respiratory tract disease
This is a disease that affects the trachea and down
Is asthma an upper or a lower tract disease
Asthma is a lower disease because it affects the bronchi and bronchioles
What is meant by Asthma exacerbations AKA acute asthma or asthma attacks
A progressive or abrupt worsening of asthma symptoms that leads to increased need for bronchiodialators and decreased pulmonary function
What is meant by status asthmaticus
Severe life threatening asthma that does not respond to standard treatments
What is the difference between atopic and non atopic asthma
Atopic: This has an external trigger [This is mediated by systemic IgE production]
Non atopic asthma: Not caused by a trigger and is as the result of local IgE production
What are the normal histological layers of the bronchioles
- Mucus
- Columbnar cells and the goblet cells
- Basement membrane
- Lamina propria
- Smooth muscles
What are the cellular changes in a patient with asthma
- Increase in goblet cells
- Increased eosinophils
- Increase neutrophils
- Increased T helper cells
- Smooth muscle hypertrophy
What is the triad of asthma
- Airflow obstruction
- Bronchial hyperresponsiveness
- Inflammation
What are the 4 cardinal signs
- Shortness of breath
- Wheeze
- Chest tightness
- Dry irritated cough
What cells to IgE bind to
Mast cells
What type of t helper cells are found in asthma
T helper 2 cells are upregulated
what is the function of t helper 1 cells
They promote cell mediated inflammation
What do T helper 2 cells work
They promote the humoral response and increased antibody production
Steps in the pathogenesis of Asthma
- Dendritic cells are activated by the allergens
- The activation of the dendritic cell as well as cytokines released by the columbnar cells causes them to differenciate into Th2 cells
- The Th2 cells will then increase humoral response producing more IgE via plasma cells and increase eosinophil production
- IgE will bind to the mast cells
What is the cytokine that stimulated the mast cells released by Th2 cells
IL9
What cytokine does Th2 cells release to stimulate eosinophils
IL 5
What is released by mast cells that causes SM contraction
Histamine
What are the clinical signs that a patient has an asthma attach
- Tachycardia
- Low O2 stats
- Pulsus paradoxis
What is the clinical sign of a silent chest and what are 3 possible causes
A silent chest is where the attach is so severe that no wheeze is heard
1. Muscle fatigue
2. Poor resp effort
3. Bronchoconstriction that is very severe
What is the first line treatment in asthma
- Supplemental oxygen
- Inhaled beta 2 agonists
- Systemic corticosteroids
What is the saturation that we are hoping for
Titrate them to stay at SaO2 of > 92%
What is the optimal way to reach the oxygen saturation in patients with asthma
Use an oxygen driven nebuliser at a rate of less than 6l/min
What is the dose of SABA in asthma patients
Neb: Salbutamol 5 mg every 20 mins
Metered dose inhaler: Salbutamol 10-20 puffs every 20 mins
What is the dose of systemic corticosteroids that is given in asthma
Oral prednisone: 30 -50 mg
IV hydrocortisone: 100-200mg 6 hourly if the oral is not tolerated
What is the second-line treatment in asthma
- Ipratropium bromide (Anticolinergic): Nebed : 0.5mg every 20mins
What is the third line treatment of asthma
1-2 g of MgSO over 20mins
When is Ipratropium bromide most useful
In severe cases of asthma in combination with B2 agonists
What is the mechanism of MgSO
It works by inhibiting SM, decreasing histamine release from mast cells and inhibiting acetylcholine
What is the 4th line treatment and what is the dose of each drug given
- IM adrenaline 0.3-0.5 mg given up to 3 times
- IV Aminophyline (increase the cAMP which causes dialation and smooth muscle relaxation): Loading dose of 5 mg/kg and then an infusion of 0.5 mg/kg/h
What is an adjunctive therapy
treatment used in addition to the primary or main treatment
What is the adjunctive theropy in an asthma patient
- Antibiotics
- IV fluids
What at 5 treatment modalities that do not work
- Leukotriene modifiers
- Antihistamines
- Mucolytics
- Sedatives
- Physio
What is the best way of monitoring the patients response to theropy
By measuring their peak expiratory flow rate at 15-30 min intervals
What are the 3 feature that make you admit an asthma patient
- If there are any feature of life threatening or near fatal asthma
- If there are any features of severe asthma 2 hours after initiating the theropy
- If there are any high risk features present
What are the 6 criteria that must be met before discharge
- Adequate response to theropy within 1-2 hours p initiating theropy
- Peak expiratory flow has improve to more than 60%
- No prolonged symptoms before the patients current admission to hospital
- No recurrents
- Absence of high risk factors
- Good social factors
What are the values of the PEF in a patient with mild, moderate and severe asthma
Mild: >80
Moderate: 80 - 60
Severe: Less than 60
