inhaled Allergen → IgE Ab→ histamine release

1. Bronchial hyperresponsiveness (fast+severe bronchoconstriction)
2. Bronchial Inflammation → mucosal edema + SM contraction
3. Bronchial obstruction
• Bronchospasm
• Edema
• incr. mucus production

Obstruction is reversible in asthma

→ spontaneously or with inhalator

work agent (direct occupational exposure)→ asthma

CLEAR RELATIONSHIP, no other cause

exacerbation of pre-existing nonoccupation asthma due to work-trigger

exacerbated or caused by work agent

a term that includes OA + WAA

• sensitizer-induced → immunological mechanism → exposure to sensitizing agent → occurance after a period of time
• high MW (molecular weight)→ animal or plant origin
• low MW → chemicals
• irritant-induced (no latency)→ direct trigger of airways-nerves + dmg epithelium → begins directly

→ ammonia, chlorin, ...= potent irritant

(in the past: Reactive airway dysfuction syndrome)

• early response(min)→ mastcell + IgE→ histamine → self limited
• late response(4-8h) → Ly, Np, Eo + IgG → persistent obstruction → beta-ago!
• dual response= both

📷

• wheezing
• dyspnea
• cough
• chest tightness
• concomitant eye+upper resp. tract symptoms

• Xray + spirometry normal (if no acute attack)
• NSHR - nonspecific hyperresponsiveness → trigger asthma attack with histamine→ decr FEV1 → pos decr. of FEV>20%
• Bronchodilator- test → give b2-agonist (salbutamol, albuterol, etc.) → what's the effect on FEV1 → if signif. incr. (≥12%, ≥200ml inc.) → positive

HISTORY!

Diagnostic criteria:

• symptoms only at/regularly after work
• improve on day off
• progression over week
• improve after change of work environment

Specific inhalation challange test (SICT) = gold standard → exposure to expected allergen

→ but expensive, special equipment, has to be in the laboratory

→ bring equipement to workplace → Across-work-shift spirometry(workplace challange)

→ but compared to SICT cant identify the specific agent + you need to send lab workers to the work place (good for large companies)

⇒ SERIAL RECORDING of PEFR(peak expiratory flow rate) 📷 is used most of the time → uses peak flow meter 📷 → patient can do that by himself and write a diary - 4x/day

→ allergen skin test + serological test (RAST,ELISA) might also be used in identifying the specif. allergic agent but they dont confirm the asthma dg.

• beta agonist (salbutamol)
• steroids
• O2
• Antibiotics
• ipratropium bromide

• he said: "acutally completely avoid exposure when asthma has developed in sensitizing-induced forms!"

→ reduction only in irritant-induced forms

• further lung function + monitoring

• Diisocyanates - coating, insulation, furniture - irritant mechanism + second. sensitizing mechanism
• Vegetable dust - cotton, → Byssinosis =monday syndrome (1-2 after return to work - milder on work-offdays)
• Metal salts - Platinum, Nikkel, Kobalt - electroplating, jewelry-making - Platinosis = asthma + rhinitis + urticaria
• Acid anhydrides - curing + hardening agents
• Wood dust - plicatic acid
• animal derived (high molecular weight)
• chemicals
• wheat
• latex
• dust
• vapour + fumes