What Is Aspirin-Induced Asthma
Asthma attack is caused by the application of certain drugs, which is called drug-induced asthma (DIA). This includes asthma attack caused by the application of certain drugs in patients with no history of asthma, and asthma attack or exacerbation of asthma caused by the application of certain drugs in patients with asthma. Aspirin-induced asthma (AIA) is the most common drug-induced asthma. According to statistics, the incidence rate of DIA in asthmatic patients is 10.5%, among which non-steroidal anti-inflammatory drugs (NSAIDs) account for 77%, while AIA accounts for two-thirds of NSAIDs-induced asthma and 50% of all DIA.
What Is The Cause Of Aspirin-Induced Asthma
History of rhinitis (10%), nasal polyps (72%), nasal mucosal hypertrophy (81.2%), the patient because of upper sense, dysmenorrhea, and after taking aspirin asthma.
1. Nosogenesis of AIA
The pathogenesis of aspirin-induced asthma has not yet been fully elucidated. It is currently recognized that COX /5- lipoxygenase imbalance is involved. Aspirin preferentially blocks cyclooxygenase to inhibit the production of prostaglandins and thromboxane, but aspirin does not block 5- lipoxygenase. A large amount of arachidonic acid substrate that cannot be utilized by cyclooxygenase generates a large amount of leukotrienes (LTC4, LTD4, LTE4) through lipoxygenase, which is a powerful bronchoconstrictor and secretagogue, which is called the "shunting hypothesis". Support the theory of research results as follows:
- The content of leukotrienes in nasal discharge, urine and bronchoalveolar lavage fluid of patients with AIA is increased.
- Pre-administration of leukotriene receptor antagonist can partially or even completely prevent aspirin-induced asthma.
2. The Nosogenesis of Asthma Induced by Other Drugs
- Allergy: The mechanism of asthma induced by antibiotics and iodinated contrast media is type I allergy mediated by specific IgE antibodies. This is also the mechanism of action of anesthetics and muscle relaxants, but they can also directly cause non-IgE mediated histamine release.
- Normal pharmacological action: β -receptor blockers, choline preparations and histamine drugs can cause bronchospasm due to their normal pharmacological action.
- Activation of complement system: In addition to causing DIA through allergic reaction, the iodine-containing contrast agent can also cause damage to vascular endothelial cells and activate the complement system, thereby releasing anaphylaxis toxin and enabling mast cells to degranulate and release histamine, thereby causing bronchospasm.
- Local stimulation of drugs on respiratory tract mucosa: Various powders, such as acetylcysteine, posterior pituitary powder and sodium cromoglycate powder, can stimulate the airway mucosa when inhaled, causing smooth muscle spasm.
- Structure similarity theory: Many drugs inducing asthma have similar benzene ring structure in their molecular structures, which can cause bronchospasm.
- Acetylation theory: some drugs can denature certain protein in the body through acetylation, and the denatured protein can stimulate the body to produce antibodies to cause allergic reactions.
- Increase of endogenous adenosine concentration: dipyridamole could block the uptake of endogenous adenosine to increase its level, and adenosine was a strong bronchoconstrictor.
What Symptom Does Aspirin-Induced Asthma Have
Aspirin-induced asthma is more common in middle-aged women and less common in children. Its typical symptoms are conjunctival congestion, nasal discharge, facial and chest skin flushing, heat rash, nausea, vomiting, diarrhea, and occasional urticaria within 30 minutes to 2 hours of medication, accompanied by chest stuffiness, asthma, and dyspnea, and in serious cases, shock, coma and respiratory arrest. Such patients have poor treatment response, so once the attack occurs, regardless of the severity of the symptoms, it should be highly valued. The combined presence of nasal polyps, aspirin allergy and asthma is known as the Aspirin Asthma Triad (Samter's Syndrome).
Drug induced asthma has the following characteristics:
- There is a clear history of medication.
- Asthma attacks occur from minutes to days after dosing.
- Asthma caused by allergic reactions in addition to respiratory symptoms and systemic allergic reactions.
- Medication after drug discontinuation can relieve most of asthma.
- Similar seizures may occur after taking this medicine in the past, or asthma attack may occur again after taking this medicine or the same kind of medicine next time.
Based on the above characteristics, it is not difficult to make a diagnosis of drug-induced asthma. For patients who suspect this disease but have an uncertain history, provocation test can be performed. Aspirin challenge test may induce severe bronchospasm with certain risk, so it must be performed by experienced medical staff under the condition of good preparation for tracheal intubation, mechanical ventilation and other rescue. This was achieved by oral administration of aspirin within three days starting at a small dose of 3 or 30mg, and lung function was measured 3 hours after dosing, which was positive if FEV1 had decreased ≥20%. If negative, continue oral administration of 60mg, 100mg up to 600mg. To shorten the test time, lysine-aspirin inhalation test was performed: 11.25-360mg/ml lysine-aspirin was inhaled 4 times at 45-minute intervals over a 350-minute period. This method was more simple, less time consuming and safer than oral administration.
How To Check For Aspirin-Induced Asthma
Bronchoalveolar lavage: Higher levels of leukotrienes in nasal discharge, urine, and bronchoalveolar lavage fluid in patients with AIA.
Note: If the clinical characteristics were consistent with the disease, but the medical history was uncertain, the provocation experiment could be performed.
How To Prevent Aspirin-Induced Asthma
Prevention: Aspirin desensitization is indicated for patients who cannot avoid the use of aspirin and other non-steroidal anti-inflammatory drugs.
The specific method is as follows:
Aspirin 20mg was given orally, followed by 40mg 2 hours later and every 2 hours until 160mg was taken. Changes in symptoms, signs and lung function were closely observed during the administration and the final dose was taken daily if there was no response. Patients should still take a daily dose of aspirin after desensitization to maintain desensitization. This treatment prevented most patients from having asthma attacks with daily oral doses of 325 to 650 mg aspirin, and cross-desensitized them to other non-steroidal anti-inflammatory drugs. For patients with AIA complicated with sinusitis and nasal polyps, active surgical treatment can also help to control AIA.
How To Treat Aspirin-Induced Asthma
Treatment: General treatment principle of drug-induced asthma: once suspected asthma patients are drug-induced asthma, suspected anti-asthma drugs will be stopped immediately; meanwhile, oxygen inhalation, keeping respiratory tract unobstructed and sputum suction will be conducted; besides, antihistamines, β receptor agonists and large dose of glucocorticoid will be given as appropriate. If the patient is suffering from steroid hormone-induced asthma, mechanical assisted ventilation shall be conducted as early as possible for severe asthma. The most effective way to prevent DIA is to avoid re-administration of these medications.
In the case of AIA, acute cases are treated according to the above principles, and chronic cases can be treated with oral or inhaled glucocorticoids. If antihistamines and mast cell stabilizers such as cromoglycate and ketotifen are used together, the symptoms will be alleviated and the dosage of glucocorticoid will be reduced. Leukotriene receptor antagonists and 5- lipoxygenase inhibitors also worked. Aspirin desensitization is indicated for patients who cannot avoid the use of aspirin and other non-steroidal anti-inflammatory drugs.
Specific methods are as follows: aspirin 20mg is taken orally, 40mg is taken orally after 2 hours, and then 40mg is increased to 160mg every 2 hours. Changes of symptoms, signs and lung function are closely observed during the administration. If there is no response, the final dose is taken every day. Patients should still take a daily dose of aspirin after desensitization to maintain desensitization. This treatment prevented most patients from having asthma attacks with daily oral doses of 325 to 650 mg aspirin, and cross-desensitized them to other non-steroidal anti-inflammatory drugs. For patients with AIA complicated with sinusitis and nasal polyps, active surgical treatment can also help to control AIA.
Prognosis: Patients with severe asthma induced by aspirin will show profuse sweating, orthopnea and purple lips, and the most severe one will die from shock and suffocation.
How To Identify Aspirin-Induced Asthma
It should be distinguished from cardiogenic asthma and variant asthma.