Aspirin-induced asthma

Introduction to Aspirin-induced Asthma Asthma attacks caused by the application of certain drugs, called drug-induced asthma (DIA), including patients with no history of asthma, cause asthma attacks after applying certain drugs, and asthma patients induce asthma attacks due to the application of certain drugs or Asthma is exacerbated by asthma, the most common of which is aspirin-induced asthma (AIA). According to foreign statistics, the incidence of DIA in asthma patients is 10.5%, of which non-steroidal anti-inflammatory drugs (NSAIDs) account for 77%; while AIA accounts for 2/3 of NSAIDs-induced asthma, accounting for 50% of all DIA. basic knowledge The proportion of sickness: 0.0045% Susceptible people: good for middle-aged women Mode of infection: non-infectious Complications: shock, coma

Aspirin induces asthma

(1) Causes of the disease

There were rhinitis (10%), nasal polyps (72%), and a history of nasal mucosal hypertrophy (81.2%). Patients had upper sensation and dysmenorrhea, and asthma occurred after taking aspirin.

(two) pathogenesis

1. The pathogenesis of AIA The pathogenesis of aspirin-induced asthma has not yet been fully elucidated. It is currently recognized that it is related to the imbalance of cyclooxygenase/5-lipoxygenase. Aspirin preferentially blocks cyclooxygenase, thereby inhibiting prostaglandins and The production of thromboxane; but aspirin does not block 5-lipoxygenase, a large number of arachidonic acid substrates that are not used by cyclooxygenase produce a large amount of leukotrienes (LTC4, LTD4, through lipoxygenase). LTE4), the latter is a powerful bronchoconstrictor and secretagogue, this is the "shunting hypothesis", the results supporting the study are: 1AIA patients nasal secretions, urine, bronchoalveolar lavage fluid white three The content of olefin is increased, and 2 pre-administered leukotriene receptor antagonists can partially or even completely prevent aspirin-induced asthma.

2. The pathogenesis of asthma induced by other drugs

(1) Allergic reactions: The mechanism of antibiotics and iodine-containing contrast-induced asthma is specific IgE antibody-mediated type I allergic reaction. The mechanism of action of anesthetics and muscle relaxants also belongs to this, but they can also directly cause non-IgE mediation. Guided histamine release.

(2) Normal pharmacological effects: -blockers, choline preparations, and histamine drugs can cause bronchospasm due to their normal pharmacological effects.

(3) Activated complement system: In addition to DIA caused by allergic reaction, iodine-containing contrast agent can also cause bronchial spasm by causing damage to vascular endothelial cells, activating the complement system, thereby releasing allergic toxins and degranulating mast cells to release histamine.

(4) Local stimulation of the drug on the respiratory mucosa: various powders such as acetylcysteine (), posterior pituitary powder, sodium cromoglycate powder, can stimulate the airway mucosa during inhalation and cause smooth muscle Hey.

(5) Structural similarity theory: Many drug-induced asthma molecular structures have similar benzene ring structures, which can cause bronchospasm.

(6) Theory of acetylation: Some drugs can denature certain proteins in the body by acetylation. This denatured protein can stimulate the body to produce antibodies and cause allergic reactions.

(7) Increase the concentration of endogenous adenosine: Dipyridamole (Pandidin) can block the uptake of endogenous adenosine, which is a strong contraction agent of the bronchus.

Aspirin-induced asthma prevention

prevention:

For patients who cannot avoid the use of aspirin and other non-steroidal anti-inflammatory drugs, aspirin desensitization can be performed as follows: oral aspirin 20mg, oral 40mg after 2h, then 40mg up to 160mg every 2h, tightly administered Observe the changes in symptoms, signs and lung function. If there is no response, take the final dose every day. After desensitization, the patient should still take a certain dose of aspirin every day to maintain the desensitization effect. This treatment can make most patients take 325~ every day. In the case of 650 mg of aspirin, asthma does not occur and cross-sensitization is performed on other non-steroidal anti-inflammatory drugs. For patients with AIA with sinusitis and nasal polyps, active surgical treatment also helps to control AIA.

Aspirin-induced asthma complications Complications, shock, coma

In severe cases, shock, coma, and apnea may occur.

Aspirin-induced asthma symptoms Common symptoms Nausea and vomiting Diarrhea Breathing difficulties Chest tightness Shock asthma Conjunctival hyperemia

Aspirin-induced asthma occurs in middle-aged women and is rare in children. The typical symptoms are conjunctival hyperemia, salivation, facial and chest skin flushing, hot rash, nausea, vomiting, diarrhea, occasional urticaria within 30 minutes to 2 hours. At the same time with chest tightness, asthma, difficulty breathing, severe cases may occur shock, coma, respiratory arrest, such patients have poor treatment response, so once the attack, regardless of the severity of the symptoms, should be highly valued, if nasal polyps, aspirin allergy and asthma The combined presence is called aspirin triad (Samter's Syndrome).

Aspirin-induced asthma examination

In bronchoalveolar lavage, the content of leukotrienes in nasal secretions, urine, and bronchoalveolar lavage fluid of AIA patients increased.

If the clinical features are consistent with the disease, but the medical history is not accurate, an excitation test can be performed.

Aspirin-induced asthma diagnosis

Diagnostic points

Drug-induced asthma has the following characteristics:

1. Have a clear history of medication.

2. An asthma attack occurs several minutes to several days after administration.

3. Asthma caused by allergic reactions in addition to respiratory symptoms also have systemic allergic reactions.

4. Give appropriate treatment after stopping the drug to relieve most asthma.

5. Previously, this drug has a similar episode, or an asthma attack may occur again when the drug or the same drug is used again.

According to the above characteristics, it is not difficult to make a diagnosis of drug-induced asthma. For those who suspect the disease, but the medical history is not accurate, an stimulating test can be performed. The aspirin stimulating test may induce severe bronchospasm and is dangerous. Therefore, it is necessary to have experienced medical services. The personnel were performed under the conditions of tracheal intubation, mechanical ventilation and other rescue preparations. The specific method was to start oral aspirin from 3 mg or 30 mg in small doses within 3 days. The lung function was measured after taking the drug for 3 hours. If FEV1 decreased by 20%, Positive, if negative, continue oral 60mg, 100mg up to 600mg, in order to shorten the test time, lysine-aspirin inhalation test: inhaled 11.25-360mg/ml lysine-aspirin at intervals of 45min in 350min, each The second 4 spray, this method is easier than oral administration, short time and safer.

Differential diagnosis

It should be differentiated from cardiogenic asthma and variant asthma.

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