Occupational asthma is a narrow airway disease characterized by intermittent episodes of wheezing and croup caused by inhalation of asthma-causing substances in the manufacturing environment. The croup can be relieved after getting rid of the asthma-causing substances.
1.Scope
This standard specifies the diagnostic criteria and management principles of occupational asthma.
This standard applies to the diagnosis and management of occupational asthma.
2.Normative reference documents
The terms of the following documents become the terms of this standard through the citation of this standard. Where the date of the reference documents, all subsequent amendments (excluding errata) or revisions are not applicable to this standard, however, the parties to the agreement under this standard are encouraged to study whether the latest version of these documents can be used. Where the reference document is not dated, its latest version applies to this standard.
GBZl8 Diagnostic Standards for Occupational Skin Diseases (General Provisions)
3. Diagnostic principles
Diagnosis is based on the exact occupational and asthma history, combined with labor hygiene and epidemiological investigation and laboratory data, and comprehensive analysis to exclude other causes of asthma or respiratory tract disorders.
4.Observation objects
Those who present with chest tightness, shortness of breath, cough and sputum with episodic asthma, and croup can be heard in both lungs, but lack of abnormal specific laboratory indexes; or those who are found to have abnormal specific laboratory indexes only in physical examination, but lack of typical clinical symptoms and signs of episodic asthma.
5.Diagnosis and grading criteria
5.1 Mild asthma
Mild asthma can be diagnosed if any of the following is present.
(1) After an incubation period of several months or years, chest tightness, shortness of breath, episodic asthma, croup in both lungs, which may be accompanied by coughing and coughing up sputum. Get rid of harmful substances, the symptoms can be relieved by themselves in a short period of time; after re-exposure, it can recur. And have any of the specific laboratory indicators abnormal;
(2) The clinical manifestations of asthma are atypical, but there are laboratory indications of increased airway reactivity (such as positive acetylcholine or histamine bronchial excitation test), and any of the specific laboratory indexes are abnormal.
5.2 Severe asthma
Recurrent asthma attacks on the basis of mild asthma with marked airway hyperresponsiveness with emphysema and persistent obstructive ventilatory dysfunction.
6.Treatment principles
6.1 Treatment principles
During the acute attack period, the patient should be removed from the work site as soon as possible, and treated symptomatically, such as oxygenation, wheezing drugs, anti-allergic drugs and Chinese medicine, etc.; if necessary, adrenal glucocorticoids should be given. For chronic recurrent attacks, in addition to the above treatment, appropriate supportive treatment is also required. See GZBl8.
6.2 Other treatment
6.2.1 Subjects for observation
Pay attention to the occurrence and development pattern of clinical symptoms and signs, establish the relationship between symptoms and occupational factors as soon as possible, conduct necessary laboratory tests, temporarily disengage from the original working environment if necessary, or conduct “disengagement and recovery” test, and treat symptomatically.
6.2.2 Occupational asthma
Immediately after the diagnosis is established, the patient should be transferred from the original workplace and given appropriate rest and treatment. After recovery, other work can be arranged. Patients with severe asthma can consider changing their living and working environment, treating symptoms, and arranging suitable harmless light work according to their health condition.
7.Instructions for the correct use of this standard
Instructions for the correct use of this standard
A.1 The scope of application of this standard: It is limited to personnel who are directly exposed to the following occupational asthma-causing substances (occupational allergens).
a) Isocyanates: toluene diisocyanate (TDl), dibenzyl diisocyanate (MDl), hexamethylene diisocyanate (HDl), naphthalene diisocyanate (NDl), etc;
b) Phthalic anhydride: phthalic anhydride (PA), 1,2,4 benzenetric anhydride (TMA), tetrachlorobenzenedicarboxylic anhydride (TCPA), etc;
c) polyamine curing agent: ethylene diamine, diethylene triamine, triethylene tetraamine, etc.;
d) Platinum complex salt;
e) sisal.
A.2 The exact occupational and medical history refers to
a) exposure to the above range of occupational asthma-causing substances (occupational allergens) at work;
b) No asthma prior to the job;
c) the occurrence of episodic or reversible asthma with pulmonary croup after performing the work;
d) reliable evidence that asthma attacks are closely related to their occupation, i.e., asthma occurs after exposure, and symptoms improve or disappear during holidays, and can recur after re-exposure;
e) Tachyphylaxis mediators, antihistamines and adrenal glucocorticoids are effective in prevention and treatment;
f) The work experience is generally more than six months.
A.3 Abnormalities of specific laboratory indicators are currently limited to
a) Positive occupational (field) bronchial excitation test;
b) positive indoor allergen bronchial excitation test;
c) Positive antigen-specific IgE antibody test (radioallergen adsorption test – RAST or enzyme-linked immunosorbent assay – ELIST);
d) Repeated positive allergen skin test (intradermal, prick or scratch method).
A.4 The diagnosis of this disease should be differentiated from upper respiratory tract infections, chronic wheezing bronchitis, cardiogenic asthma, exogenous allergic alveolitis, and non-occupational primary bronchial asthma.
Appendix B
(Normative Appendix)
Specific allergen skin test
B.1 Patch test
According to GBZ18-2002 Appendix C (normative appendix) implementation.
B.2 Intradermal test
B.2.1 Operating procedures
B.2.1.1 The subject is routinely disinfected on the outside of the upper arm.
B.2.1.2 Use a sterilized lml tuberculin syringe and 26-27 intradermal needle to extract the test solution and inject about 0.02-0.1ml into the skin, the local skin is pale and rounded, 3-4mm in diameter, and should not bleed.
B.2.1.3 Perform antigenic lysis control test on the upper arm of another case at the same time.
B.2.2 Observation and judgment
Observe the reaction results 15-20 min after injection, and the judgment criteria are
No local skin reaction, or only a small papular or erythematous reaction similar to that of the control (-)
Local skin papules less than 0.5cm in diameter and less obvious erythema reactions (±)
Local skin papules 0.5-1.0 cm in diameter with erythema reaction (+)
Local skin papule diameter of 1.1-1.5cm with obvious erythematous reaction (++)
Local skin papule diameter greater than 1.5cm, with obvious erythema reaction and pseudopod (++)
The subject local skin reaction with (++++), and at the same time the appearance of peripheral reactions such as itchy skin, flushing, breath-holding, asthma and other symptoms (++++)
B.2.3 Precautions
a) The skin test should be performed in remission;
b) Skin test is not recommended for those with obvious skin scratching;
c) Antihistamines should be stopped before the test, and adrenal glucocorticoids should be stopped when conditions permit;
d) The antigen used should be sterile and the concentration should be appropriate. The test operation should be accurate and should not bleed;
e) attention should be paid to the presence of systemic reactions, and emergency drugs should be available in case of emergency.
B.3 Scratch test
B.3.1 Operation steps
B.3.1.1 The subject’s skin is routinely disinfected on the lateral upper arm or medial forearm and washed with distilled water or saline. B.3.1.2 After the skin is dry, make a direct scratch with the tip of a needle, each scratch is 3-5 mm long, to prevent bleeding.
B.3.1.3 Place a drop of skin test solution on the scratch.
B.3.1.4 Perform a control test with antigenic solvents.
B.3.2 Observation and judgment
Observe the reaction results 15-20 min after scratching, and the judgment criteria are
The local skin of the scratch is the same as the control test (-)
Scratch local skin slightly elevated, surrounded by light red spots (+)
Scratch local skin papule-like elevation, the length of which exceeds the length of the scratch, and surrounded by obvious erythema around the papule (++)
Localized papular elevation of the skin with pseudopods surrounded by a distinct irregular erythematous reaction (+++)
Scratch localized skin papule with more than two pseudopods, itchy, surrounded by obvious skin erythema (++++)
B.3.3 Precautions
Same as B2.3.
If a strong skin reaction occurs less than 15 min after the skin test, the antigen can be swabbed away with cotton dipped in distilled water to avoid further development of the reaction.
B.4 Prick test
B.4.1 Procedure
B.4.1.1 The subject’s skin is routinely disinfected on the medial side of the anterior canal or the lateral side of the upper arm.
B.4.1.2 Apply a drop of skin test solution to the skin test site.
B.4.1.3 Use a special puncture needle (or use a common injection needle instead) to puncture 0.5~1mm parallel to the skin surface in the center of the skin with the drop of skin test solution, and then raise the needle tip slightly to allow the skin test solution to flow into the skin, and then withdraw the needle quickly. The excess skin test solution should not bleed throughout the operation.
B.4.1.4 Control test with antigenic lysis medium.
B.4.2 Observation and judgment
Observe the reaction 15～20min after puncture. The judgment method can directly record the size of the diameter of the wind mass and erythema and compare it with the control to determine whether it is positive or not (normal control should have no wind mass or only a small mound less than 3mm in diameter with no erythema around it).
B.4.3 Precautions
Same as B2.3.
Appendix C
(Normative Appendix)
Determination of antigen-specific IgE – radioallergen adsorption test (RAST)
C.1 Principle
Allergens are cross-linked to a solid-phase polymer, such as glucose gel, cellulose particles or paper, and then added to the serum under test. The specific antibody (1gE, etc.) in the serum binds to the allergen, the excess serum is washed away, 125I-labeled anti-IgE conjugate is added, and after a certain period of incubation, a solid phase carrier a allergen a specific IgE an anti-IgE, 125I complex is finally formed. Excess labeled antibodies were washed away. The amount of specific IgE in the serum can be known by measuring the amount of radiotracer left on the paper sheet with a Y-ray counter.
C.2 Equipment
Xinhua filter paper or Watterman I filter paper, micro sparger, Brinell filter paper, y-ray counter, negative pressure attractor, magnetic stirrer, pH meter or test paper.
C.3 Reagents
a) Allergens;
b) cyanogen bromide;
c) 0.01 mol/L (pH 7.4) phosphate buffer;
d) 5 mol/L potassium phosphate solution;
e) 0.005moL, 0.1/L sodium bicarbonate solution;
f)Horse anti-human IgE-IgG;
g)acetone;
h) 1 mol/L, 0.05 mol/L ethanolamine;
i)0.1moI/L (pH 4.0) acetic acid-sodium acetate buffer;
j) Bovine serum albumin, or human serum albumin (HSA).
C.4 Methods
C.4.1 Preparation of cyanogen bromide activated filter paper sheets
Wartman I or Xinhua filter paper, punched into 6mm diameter paper sheets (100 sheets about 300mg) with a punch.
Weigh 4g of cyanogen bromide with 80ml of double-distilled water, dissolve in water bath and stir. Weigh 4g of paper sheet into a triangular flask with stopper and soak it in cold double-distilled water for 30min. aspirate the distilled water and add 80ml of 5% cyanogen bromide solution. adjust the pH at about 11 with 5mol/L pre-chilled phosphate, stir for 8min and keep adjusting the pH value. Then wash with 800ml of 0.005mol/L sodium bicarbonate in 5 successive times, and then wash with 400ml of double distilled water for 3 to 4 times. Finally, wash with 400ml acetone for 4 times consecutively and put it in a large flat dish to draw dry.
C.4.2 Preparation of antigen (varies according to the type of antigen)
C.4.3 Coupling protein: weigh 30mg HSA and dissolve with 0.1mol/L sodium bicarbonate 60mi. Put 15ml of HSA solution into each 200 pieces of paper and rotate the drum at 8C for 48h. Wash 3 times with 0.1mol/L sodium bicarbonate and 3 times with 0.01mol/L (pH7.4) PBS.
C.4.4 Coupling antigen: Prepare the appropriate concentration of antigen, add the paper sheet and rotate the drum at 8℃ for 48h, followed by 3 washes with 0.01mol/L (pH7.4) PBS solution.
C.4.5 Closure: Add the above paper sheets with 0.25 mol/L ethanolamine 15 ml, SC, drum for 8h, wash 3 times with 0.1 mol/L sodium bicarbonate, 3 times with 0.1 mol/L (pH 4.0) sodium monoacetate, and 3 times with 0.01 mol/L (pH 7.4) PBS. Store at 4℃ for backup.
C.4.6 RAST test procedure
C.4.6.1 Place the paper pieces coupled with antigen and protein in the bottom of the test tube, 1 piece per tube.
C.4.6.2 Add 50uL of the serum to be tested at a certain dilution concentration (generally 1:5) to the filter paper disc for each tube, and take 50uL of buffer and negative serum each and add them to the filter paper disc as control, cover and incubate for 3h at room temperature.
C.4.6.3 Remove the liquid from each tube with a negative pressure aspirator and then wash 3 times with 0.05 mol/L (pH 7.4) PBS containing 0.3% horse serum.
C.4.6.4 Add 125I-labeled horse anti-human IgE antibody 50uL (approximately 5 to 80,000 CMP) to each tube of filter paper discs. Leave overnight at room temperature, after which wash 3 times as above.
C.4.6.5 Measure the radioactive intensity (CPM/min) by Y-counter after aspiration and compare with normal human, and a score greater than two standard deviations (2SD) of the normal mean is considered positive.
Appendix D
(Normative Appendix)
Antigen-Specific IgE Assay – Enzyme-Linked Immunosorbent Assay (ELIST)
D.1 Principle
Allergen is conjugated to solid phase carrier – concave polystyrene plate, and serum to be tested is added to make specific binding of antigen and antibody, then horseradish peroxidase labeled secondary antibody (horse anti-human IgE) is added to form a complex of antigen, antibody and anti-antibody, and after color development by substrate, the OD value is measured by ELIST to know the specific antibody content in serum. content.
D.2 Equipment
Concave polystyrene plate, microfiller, enzyme-labeled immunoassay, PH test paper, thermostat, refrigerator, wash bottle, wet box, common glass instruments, etc.
D.3 Reagents
a) Human serum albumin (HSA) (0.05%);
b) Allergen;
c) 0.02 mol/L (pH 7.4) phosphate buffer solution (PBS);
d) Tween-20 (Tween-20) (0.05 ml per 100 ml PBS solution to make PBS-T);
e) Bovine serum albumin (BSA) or calf serum (10%);
f) 0.05 mol/L (pH 9.6) carbonate buffer;
g) pH 5.0 phosphate monocitrate buffer;
h) o-phenylenediamine (OPD);
i) 30% hydrogen peroxide;
j) Horseradish peroxidase-labeled horse anti-human IgE;
k) 2 mol/L sulfuric acid.
D.4 Methods
D.4.1 Encapsulated HSA, 37°C, 2L.
D.4.2 PBS-T wash 3 times.
D.4.3 Add allergen overnight at 4°C.
D.4.4 Wash 3 times with PBS-T.
D.4.5 Add the serum to be tested (diluted with PBS-T, containing 1% BSA, 1:5 dilution) at 37°C for 90 min.
D.4.6 Wash 6 times with PBS-T.
D.4.7 Add the enzyme-labeled antibody, 37°C, 90min.
D.4.8 Wash 8 times with PBS0-T.
D.4.9 Add substrate solution 0.02% OPD containing luL/10ml hydrogen peroxide, 37°C, 30min.
D.4.10 Terminate the reaction with 2 mol/L sulfuric acid.
D.4.11 Determine the OD value by enzyme-linked immunomonitoring at 492 nm.
D.4.12 Result determination: greater than the normal mean value of 2SD is positive.
Appendix E
(Normative Appendix)
Allergen bronchial excitation test
E.1 Indoor allergen re-tracheal excitation test
E.1.1 Pre-test preparation and basic conditions
E.1.1.1 Performed in remission (asymptomatic) of asthma.
E.1.1.2 Discontinue β-adrenergic receptor stimulants and a-adrenergic receptor blockers 8-12 h before the test, phosphodiesterase inhibitors 18-24 h before the test, sodium cromoglycate and antihistamines 24 h before the test, and adrenal glucocorticoids 3-5 days before the test.
E.1.1.3 Stop smoking and consuming stimulating foods and beverages within 6 h before the test, and avoid excessive exercise.
E.1.1.4 The subject has no recent upper respiratory tract infection.
E.1.1.5 Prepare safety first aid measures, such as oxygen and drugs.
E.1.2 Method
The standardization of this test method has not been completed in China, therefore, the following principles should be followed at least in practice.
E.1.2.1 Select a suitable and effective bronchial excitation test method. The commonly applied methods are
a) Devilbiss 646 nebulizer with 5 deep inspirations in the functional residual position, releasing a quantitative aerosol at 0.6s at the beginning of each inspiration;
b) Tidal breathing with the Wrights’ nebulizer for 2 min;
c) direct measurement of airway reactivity by an airway allergometer (Astograph) manufactured in Japan.
In addition to the above three methods, other compliant methods and nebulizers can also be used, and a device to determine the amount of nebulization can be tested. The aerosol particles produced by the nebulizer should be less than 5um in diameter on average.
E.1.2.2 The antigen volume of the bronchial excitation test should be the smallest dose to which the patient is exposed and which elicits a bronchial response. The presence of a 3 mm dermatome (++), or 200 protein nitrogen units/ml, or an antigen concentration of 10-5 to 10-3 (W/V) on the puncture test can be used as a reference for the aspirate antigen concentration. In determining the amount of each antigen, the principle of starting with a small dose and gradually increasing the amount of aspirate should be followed.
E.1.2.3 Pulmonary function index (FEV1.0) is measured before the test, as the base value, the difference between the two results is not more than 5%; if the antigen is added to a certain dilution, before the antigen is inhaled, the test should also be conducted after the dilution is inhaled, as a control value, the value should not change more than 10% of the base value.
E.1.2.4 The first second exertional spirometry (FEV1.0) can be used as a measure of the bronchial excitation test, as well as other indices such as airway conductivity (Sgaw). The interval of observation should be no longer than 15-30 min during the first 1/J’ of inhalation.
E.1.2.5 In addition to observing the reaction within 2h (mostly in 10-30min) after inhalation of allergens, attention should also be paid to the delayed or bidirectional reaction occurring within 4-6h, therefore, the total observation time should be 24h.
E.1.3 Positive reaction criteria
E.1.3.1 FEVl.0 is more than 15% lower than before the inhalation of antigen. It is calculated as follows
E.1.3.2 If there are obvious symptoms and signs after excitation, such as chest tightness, shortness of breath, severe cough, lung rales, etc., the upper value should be relaxed, (more than 10%) is judged as positive.
E.1.4 Precautions
a) The concentration of allergen inhalation should not be too high to avoid irritation;
b) The test should not be performed for certain strong allergens (e.g. penicillin, etc.) or if the patient has a history of hypersensitivity (e.g. anaphylaxis) or other significant systemic disorders;
c) The test should not be performed on patients with extremely poor cardiopulmonary status, FEV1.0<1L;
d) Given that the test requires certain equipment and technical conditions, and that overreaction may occur in individual cases during the test, the test should be performed in a qualified hospital;
e) It is not advisable to imply before or during the test, and the spirit should not be too nervous.
E.2 Occupational (field) bronchial excitation test
E.2.1 Pre-test preparation and basic conditions
Same as E.1.1. E, 2.2 Method
E.2.2.1 Measure the ventilation function (FEV1.0) every 15 min during the first hour after entering the work site. In the second hour, the ventilation function is measured every half hour. According to the situation can stay at the site 1 ~ 2h.
E.2.2.2 After de-exposure, measure pulmonary function every 1 hour, and note and record clinical symptoms and signs. Continuous observation for at least 8h, 24h should be measured again.
E.2.2.3 If there is a significant decrease in lung function index and respiratory symptoms and signs, the excitation test may be terminated, i.e., aspirate with bronchodilator drugs such as albuterol spray, and observe the recovery of lung function index.
E.2.3 Positive reaction criteria
Same as E.1.3.
E.2.4 Precautions
Same as E.1.4.