Asmtha Flashcards
What is the underlying pathophysiology of asthma?
Asthma is a chronic inflammatory disorder causing airway hyperresponsiveness, reversible airflow obstruction, and bronchial inflammation.
What immune response is primarily responsible for asthma?
Asthma is mediated by IgE against environmental antigens, leading to mast cell degranulation, eosinophilic inflammation, and bronchoconstriction.
What are common triggers of asthma?
Allergens, tobacco smoke, air pollution, respiratory infections, cold air, and exercise.
At what age is asthma typically diagnosed?
Asthma is rarely diagnosed before 2-3 years of age due to lung development. It is important to not that lungs don’t stop growing until 8 years old.
What are the hallmark symptoms of asthma?
Intermittent dyspnea, wheezing, chest tightness, and dry cough.
What are the characteristic lung function changes during an asthma exacerbation?
Decreased FEV1, normal FVC, and increased TLC over time due to air trapping.
How is asthma diagnosed?
Clinical diagnosis confirmed by spirometry showing reversible airflow obstruction (≥12% and 200 mL improvement in FEV1 after bronchodilator).
What tests are used if spirometry is inconclusive?
Methacholine challenge or exercise challenge testing or exercise challenge. There can occasionally be a diagnosis established due to “workplace exposure.”
If a patient says they might be allergic to “work,” should you take it seriously?
Yes!
How is intermittent asthma classified?
- Symptoms <2 days/week
- Night awakenings <2 times/month,
- Normal lung function (FEV1 >80%)
- ≤1 exacerbation per year
What is the treatment for intermittent asthma (Step 1)?
Short-acting beta-agonist (SABA) such as albuterol as needed.
What is mild persistent asthma?
- Symptoms ≥2 days/week
- Night awakenings 3-4 times/month,
- FEV1 >80%
- ≥2 exacerbations per year.
What is the treatment for mild persistent asthma (Step 2)?
Low-dose inhaled corticosteroid (ICS) and SABA as needed.
What is moderate persistent asthma?
- Daily symptoms
- Night awakenings >1 time/week
- FEV1 60-80%
- ≥2 exacerbations per year
What is the treatment for moderate persistent asthma (Step 3)?
Low-dose ICS + long-acting beta-agonist (LABA) such as formoterol or salmeterol.
What is severe persistent asthma?
- Symptoms throughout the day
- Nightly awakenings
- FEV1 <60%
- Frequent exacerbations
What is the treatment for severe persistent asthma (Step 4-5)?
High-dose ICS + LABA, with the addition of biologics or oral steroids if necessary.
Which biologic is used for asthma with high IgE levels?
Omalizumab (anti-IgE).
Which biologics are used for eosinophilic asthma?
Mepolizumab and dupilumab (anti-IL-5/IL-4).
What leukotriene receptor antagonists can be used in asthma, what can develop as a consequence?
Montelukast and zafirlukast. Montelukast can be associated with ANCA-associated vasculitis (EGPA/Churg-Strauss Syndrome, eosinophilic granulomatosis with polyangiitis), P-ANCA (MPO-ANCA). In general, asmatics are at increased risk for developing P-ANCA-associated vasculitides, particularly Eosinophilic Granulomatosis with Polyangiitis (EGPA, formerly Churg-Strauss Syndrome), even without taking montelukast. Treatment of EGPA includes corticosteroids and immunosuppressants (e.g., cyclophosphamide, rituximab, mepolizumab in refractory cases). Churg-Strauss syndrome is characterized by perivascular eosinophilic inflammatory infiltrates and presents with asthmatic symptoms and pulmonary infiltrates. It is also typically accompanied by allergic rhinitis, sinusitis, nasal polyps, and skin lesions. Additionally, patients may also experience mononeuropathy multiplex is a condition characterized by damage to multiple, isolated peripheral nerves, resulting in weakness, numbness, tingling, and pain in various parts of the body.
What are the more common side effects associated with leukotriene receptor antagonists?
Elevated liver enzymes (zileuton) and neuropsychiatric symptoms (montelukast).
What is the first step in managing an asthma exacerbation?
Assess severity, provide oxygen to maintain SpO2 >92%, and administer nebulized SABA (albuterol) with ipratropium.
When are systemic steroids given for asthma exacerbation?
If symptoms are severe or if there is poor response to initial bronchodilator therapy.
What medication is used for severe exacerbations unresponsive to initial treatment?
IV magnesium sulfate.
What sign suggests impending respiratory failure in an asthma exacerbation?
Normalizing or rising PaCO2 despite tachypnea, indicating ventilatory failure and need for intubation.
How long can systemic steroids be used without tapering?
A short course (<2 weeks) does not require tapering due to minimal hypothalamic-pituitary-adrenal (HPA) axis suppression.
What are complications of long-term systemic steroid use?
Adrenal suppression, osteoporosis, weight gain, hyperglycemia, and steroid-induced psychosis.
When SHOULD steroids be tapered for acute asthma exacerbations?
Cushing symptoms or more than 2 weeks of use.
What could patients with asthma be provided instead of PO steroids?
Long-term management of poorly controlled asthma after an exacerbation may also include inhaled corticosteroids, which have fewer adverse effects than oral glucocorticoids due to limited systemic bioavailability. It is important to know that of all the medication’s available the best way to decrease the chance for acute asthma exacerbation reoccurrence is with the use of PO steroids.
When should bisphosphonates and vitamin D be given for steroid users?
For patients on long-term steroids to prevent osteoporosis.
What are the side effects of albuterol?
Tachycardia, hypokalemia, and tremors.
Why should ICS be used with a spacer and mouth rinsing?
To reduce the risk of oropharyngeal candidiasis.
When can a patient be discharged after an asthma exacerbation?
Once peak expiratory flow (PEF) reaches >80% of predicted.
What is aspirin-exacerbated respiratory disease (AERD)?
A condition where NSAIDs or aspirin trigger asthma, chronic rhinosinusitis, and nasal polyps (Samter’s Triad). Avoid NSAIDs, use leukotriene receptor antagonists (montelukast, zileuton), and manage asthma conventionally.
A patient with asthma gave birth vaginally to a baby large for gestational age moments ago, she is experiencing hypovolemic shock and was given oxytocin, but kept bleeding. What is the best course of management?
When postpartum hemorrhage (PPH) is refractory to oxytocin, the next step is to administer a second-line uterotonic agent. However, because the patient has asthma, carboprost tromethamine (Hemabate, PGF2-alpha) is contraindicated, as it can cause bronchospasm due to its prostaglandin F2-alpha-mediated bronchoconstriction. The best alternative in this case is Misoprostol (PGE1) or Dinoprostone (PGE2).
A 24-year-old woman with a history of asthma comes to the emergency department at 32 weeks gestation with a 5-day history of increased dyspnea, wheezing, and cough. Her asthma was previously well-managed with a combination fluticasone-salmeterol inhaler twice daily, but the patient stopped using it when she discovered she was pregnant. She reports no nasal congestion, sore throat, or sinus pain. The patient has no other medical conditions, and her pregnancy has progressed normally. Her only other medication is a prenatal multivitamin. She does not use tobacco, alcohol, or illicit drugs. Her father has a history of asthma. On examination, the patient appears to be in mild respiratory distress. She is afebrile. Blood pressure is 110/68 mm Hg, pulse is 104/min, and respirations are 21/min. Pulse oximetry is 94% on room air. Lung examination reveals inspiratory and expiratory wheezes with a prolonged exhalation phase. Heart sounds are normal. Mild bilateral pitting pedal edema is present; there is no calf tenderness in either leg. Fetal heart rate monitoring is reassuring. Nebulized albuterol and inhaled ipratropium are administered and provide some relief. On repeat assessment shortly afterward, the patient continues to feel short of breath, and wheezing is still present on examination. Arterial blood gas analysis shows a pH of 7.45, PaCOz of 26 mm Hg, and PaOz of 100 mm Hg on 2 L of oxygen by nasal cannula. What is the best next step in management of this patient?
Pregnancy increases respiratory drive, leading to chronic respiratory alkalosis (PaCOz of 27-32 mm Hg); hyperventilation during asthma exacerbation causes superimposed acute respiratory alkalosis. Relative acidosis (normalization of the PaCO2) during asthma exacerbation suggests impending respiratory failure and is an indication for mechanical ventilation. This patient’s arterial blood gas suggests acute-on-chronic respiratory alkalosis, consistent with an appropriate respiratory response. This patient has an acute asthma exacerbation during pregnancy. Poorly controlled asthma is strongly linked to maternal and fetal mortality, premature birth, and low birth weight. The treatment of acute asthma exacerbations in pregnant women and nonpregnant patients is similar. Treatment involves Bronchodilator therapy, Systemic corticosteroids, and Supplemental oxygen. Bronchodilator therapy is provided with an inhaled or nebulized albuterol is given initially, usually along with inhaled ipratropium. Intravenous magnesium sulfate or terbutaline may be needed for refractory bronchoconstriction. Provide systemic corticosteroids, especially in patients who have an incomplete response to bronchodilators, high-risk asthma features (eg, previous intubation), or a breakthrough acute exacerbation despite taking controller medications. Supplemental oxygen should be given to maintain SaO2≥95% (vs ≥90% in nonpregnant patients) to prevent antenatal fetal hypoxia. There is inconsistent evidence for a weak association between systemic corticosteroids and negative outcomes such as prematurity and cleft palate. When systemic corticosteroids are needed, patients should be reassured that the benefits of pharmacotherapy far outweigh any risk to the mother or fetus.
