GENERAL INFORMATION
• It is a chronic inflammatory disease of the large and small airways, accompanied by increased bronchial hyperresponsiveness, eosinophil and mast cell infiltration, and reversible airway obstruction.
• It is the most common chronic inflammatory lung disease of childhood.
Pathological changes in the airway in asthma
• Epithelial desquamation
• Basal membrane thickening (the most pathognomonic pathological finding of asthma)
• Eosinophilic inflammation
• Mucous gland hypertrophy
• Excess mucus secretion and mucous plugs
• Vasodilation, increased permeability and edema
• Subepithelial fibrosis, Smooth muscle hypertrophy, Revascularization: Permanent changes in chronic cases
Asthma has 3 important clinical features:
1. Reversible (reversible) airway obstruction
2. Airway inflammation (increased exhaled NO)
3. Airway hypersensitivity (methacholine sensitivity)
Factors affecting the emergence and course of asthma
• The most important risk factor affecting the development of persistent asthma in childhood is atopy and clinically it can be seen as atopy, atopic dermatitis, allergic rhinitis or food allergy.
• Living in rural and agricultural communities is protective for asthma
Early childhood risk factors for persistent asthma
Parental asthma
Allergy
. atopic dermatitis
. allergic rhinitis
. food allergy
. Inhaled allergen sensitivity
. food allergen sensitivity
severe lower respiratory tract infection
. pneumonia
. Bronchiolitis requiring hospitalization
wheezing without a cold
male gender
Decreased lung functions at birth
low birth weight
Exposure to environmental cigarette smoke
Feeding with formula
Clinical findings in asthma
• Cough, shortness of breath, chest pain, tachypnea, wheezing, night-time coughing, exercise intolerance, excessive sweating.
Characteristics of symptoms in asthma
• Having a repetitive character and seizures
• It develops more at night and / or towards the morning
• Relief or disappearance spontaneously or with drugs
• Having occasional symptom-free periods
• It shows seasonal variation
• Triggering symptoms by various factors
Physical Examination Findings
• If the patient is not in an asthma attack, it can be found to be normal. With this;
- Prolonged expiration (inspiratory time is usually normal)
- tachypnea
- Wheezing on expiration (in severe cases, it can also be heard on inspiration)
- rales
- There are intercostal and subcostal retraction, dyspnea.
- In severe cases, there is cyanosis and silent lung.
Diagnosis of athma
Tests used in diagnosis
1. Chest X-ray: Flattening in the ribs and diaphragm, bilateral aeration excess
2. Pulmonary function tests
- FEVl/FVC low (<80%)
- FEV1 (PEF) <80% and at least 12% increase in post-bronchodilator FEV1 or more than 10% increase in predicted FEV1.
- ≥20% of morning-evening PEF variability
- >15% worsening in FEV1 after exercise
3. Skin tests
4. Eosinophilia (>4%)
5. Total-specific IgE elevation
6. Exhaled NO measurement
- Measurable in patients 5 years and older
- >20 ppb: Supports asthma diagnosis
- <20 ppb: low response to inhaled corticosteroids
- 20-35 ppb: moderate response to inhaled corticosteroids
- > 35 ppb: responds well to inhaled corticosteroids
7. Bronchial stimulation tests (BPT): Stimuli that cause airway limitation in bronchial hypersensitivity (BAD) are direct stimuli (such as acetylcholine, methacholine, histamine, carbachol) and indirect stimuli (adenosine, exercise, hyper/hypotonic aerosols, isocapnic hyperventilation.) according to their mechanism of action. They are divided into two groups.
BAD is evaluated with bronchial provocation tests (BPT) in clinical practice. Although many different methods are used, the most commonly used methacholine is BPT.
A 20% reduction in FEV1 after methacholine inhalation is positive.
The only specific stimulant used in the bronchial stimulation test is the sensitizer inhaler.
8. There are Charcot-Leyden crystals and Curshman spirals in sputum.
Treatment of Asthma
acute attack treatment
The most valuable and useful method in the follow-up of the asthmatic patient in the emergency department is the PEFR (expiratory peak flow rate) measurement.
• Oxygen is given by mask. If the patient is agitated, he is taken to a quiet room. PaO should be >92%
• Short-acting beta2 agonists; albuterol, salbutamol, terbutaline, metaproteranol, levabuterol, pirbuterol:
- Drugs of first choice in acute asthma attack.
- It can be given 3 times with an interval of 20 minutes. It can be given as 0.1-0.15 mg/kg inhaler/nebulizer.
- Bronchodilator relaxes bronchial smooth muscles with its β2 agonist effect.
- As a side effect; tremor, irritability, tachycardia, hypokalemia, hyperglycemia, hypomagnesemia and CNS stimulation can be seen.
- Transient hypoxemia may develop due to short-acting beta2 agonists given during the treatment of acute asthma attack, and due to ventilation-perfusion balance deterioration.
• Short-acting anticholinergic agents (ipratropium bromide): They inhibit the vagal reflex by inhibiting the release of acetylcholine from muscarinic nerve endings. It is less effective than β2 agonists. In acute and severe attacks, it is given together with short-acting β2 agonists due to its bronchodilator effects.
• Systemic steroids: 1-2 mg/kg methylprednisolone (maximum 60 mg/24 hours) is used especially in moderate-severe asthma attacks. In daily use, the same dose is given by dividing into two. In out-of-hospital treatment, 1-2 mg/kg/day methyl prednisolone (3-10 days) can be used orally.
• Epinephrine: 0.01-0.03 mg/dose (maximum 0.5 mg) SC can be used in severe attacks. It causes vasoconstriction with alpha adrenergic effect and bronchodilation with β adrenergic effect.
• Inhaled steroid: It can be used at home and in mild attacks. It is not used in the emergency room.
• IV Magnesium sulfate: It can be used in acute and severe asthma attacks. Magnesium causes neuromuscular block by inhibiting Ach release from cholinergic nerve endings without affecting the central respiratory center. It also acts as a bronchodilator by antagonizing calcium in bronchial smooth muscle cells and preventing muscle contractions. It also inhibits histamine release from mast cells.
• IV Theophylline: It can be used in acute and severe asthma attacks.
• IV beta 2 agonist (Terbutaline, salbutamol): In severe asthma attacks, the first dose can be given as a continuous IV infusion in those who do not respond adequately to short-acting beta2 agonist + anticholinergic and systemic steroid treatment. It must be given in the intensive care unit.
• Heliox (70:30% Helium and oxygen mixture): It reduces airway resistance as its density is 1/3 of the room air. It can be used in acute and severe asthma attacks.
Chest physiotherapy, aspiration, spirometry and mucolytics are not recommended during an attack as they may increase bronchospasm.
Complications of Asthma
1. Respiratory failure
2. Atelectasis
3. Air leaks (pneumothorax, pneumomediastinum): Asthma is the most common cause of spontaneous pneumomediastinum in children.
4. Inappropriate ADH release
5. Neuromyopathy (Hopkins syndrome): It can be seen in severe asthma attacks. It is rare. It is characterized by permanent flaccid paralysis of the arms and legs.
6. Cardiac and respiratory arrest
7. Brain damage
8. CHF
Long-Term Treatment of Asthma
savior drugs
• Short-acting beta-2 agonists
• Systemic steroid
• Theophylline (aminophylline)
• Anticholinergics (Ipratropium bromide)
control drugs
• Inhaled and systemic corticosteroids
• Cromolyn and nedocromil
• Leukotriene antagonists
• B2 long-acting agonists (LABA)
• Theophylline
• Anticholinergics (Tiotropium)
• Anti lgE (Omalisumab)
• Anti IL5 (Mepolizumab)
• Inhaled corticosteroid is the drug of first choice in children.
• If there is no response to this treatment, the dose is doubled and/or a long-acting β2 agonist or leukotriene receptor antagonist can be added.
• In monotherapy, only inhaled corticosteroid or leukotriene receptor antagonist can be used as a single drug. Long-acting β2 agonists should not be used alone.
• Long-acting anticholinergic agents (tiotropium): It is used over 12 years of age. In combination with inhaled corticosteroids, it has been found to be equally effective with long-acting beta-agonsides. It has no place in the treatment of attacks, but it reduces the frequency of attacks.
• Allergen immunotherapy: administered sublingually or subcutaneously. Subcutaneous applications were found to be more effective, but the risk of anaphylaxis is higher.
• Omalizumab (Anti-IgE monoclonal antibody): Monoclonal anti-IgE binds free circulating IgE. It suppresses early and late allergic response and reduces sputum eosinophilia. It is used in severe persistent asthma that cannot be controlled with inhaled corticosteroids and over 6 years of age.
• Mepolizumab (Anti IL-5): It reduces sputum and blood eosinophilia. Decreases steroid dose, increases asthma control. Used for ages 12 and up.
• Dupilumab (Anti IL-4 receptor alpha antibody)
CHILDHOOD ASTHMA TYPES
• In 80% of asthmatic patients, the disease starts before the age of 6 years.
• In a very small proportion of these children, asthma continues in late childhood.
• According to the natural course in children, there are 2 types of asthma.
1- Recurrent wheezing
2- Persistent asthma
3- Asthma with deterioration in respiratory functions
Recurrent wheezing
• It is common in the preschool age group.
• Attacks are usually triggered by viral upper respiratory tract infections.
• It usually resolves at preschool or early school age.
• Airway hypersensitivity present after birth disappears towards school age.
Persistent atopy associated asthma
• It begins at an early preschool age.
• It is associated with atopy in early school age.
• It is closely associated with abnormal pulmonary function in late childhood and adulthood:
- Respiratory functions are found to be decreased in school age in those who start before the age of three.
- Respiratory functions are not impaired in those with symptoms or allergic sensitization after the age of three
Indent asthma with impaired respiratory function
• It goes with progressive deterioration in respiratory functions in men and starts after 3 years of age.
Asthma associated with the risk of asthma in the preschool age group
Major criteria
- Asthma in parents
- Doctor-diagnosed atopic dermatitis
- Inhaled allergen sensitivity
Minor criteria
- Allergic rhinitis diagnosed by a doctor
- Wheezing without a cold
- Eosinophilia (>4%)
- Food allergen sensitivity.
Presence of 1 major or 2 minor criteria is considered positive. The probability of these patients to be diagnosed with asthma after the age of 6 is 76%.
• If criteria are negative, probability of not developing asthma after age 6 = 97%
