Medical expert of the article

Allergist, immunologist, pulmonologist

New publications

Toxic fibrosing alveolitis: causes, symptoms, diagnosis, treatment

Alexey Kryvenko, medical expert
Last reviewed: 06.07.2025

All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.

We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.

If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.

Toxic fibrosing alveolitis is a form of fibrosing alveolitis caused by the effect of substances with cytotoxic properties on the lung parenchyma.

Causes of toxic fibrosing alveolitis

Toxic fibrosing alveolitis is caused by two groups of factors - medicinal chemotherapeutic agents and industrial toxic substances. Toxic fibrosing alveolitis can be caused by the following medicinal substances:

alkylating cytostatic drugs: chlorbutine (leukeran), sarcolysine, cyclophosphamide, methotrexate, myelosan, 6-mercaptorurine, cytosine arabinoside, carmustine, 5-fluorouracil, azathioprine;
antitumor antibiotics: bleomycin, mitomycin-C;
cytostatics obtained from medicinal plants: vincristine, vinblastine;
other antitumor drugs: procarbazine, nitrosomethylurea, thioguanoside, uracil mustard;
antibacterial agents: nitrofuran derivatives (furazolidone, furadonin); sulfonamides;
antifungal drug amphotericin B;
antihypertensive drugs: apressin, anaprilin (obzidan, inderal and other beta-blockers);
antiarrhythmic drugs: amiodarone (cordarone), tocainide;
enzymatic cytostatic drug L-asparaginase;
oral hypoglycemic drug chlorpropamide;
oxygen (with prolonged inhalation).

Toxic industrial substances that cause toxic fibrosing alveolitis include:

irritating gases: hydrogen sulfide, chlorine, carbon tetrachloride, ammonia, chloropicrin;
vapors, oxides and salts of metals: manganese, beryllium, mercury, nickel, cadmium, zinc;
chlorine and organophosphorus insectofungicides;
plastics: polyurethane, polytetrafluoroethylene;
nitro gases formed in mines and silo towers.

The incidence of toxic fibrosing alveolitis depends on the duration of drug administration and its dose and on the duration of exposure to the occupational toxic factor.

Pathogenesis

The main pathogenetic factors of toxic fibrosing alveolitis are:

damage to the microcirculatory bed of the lungs (necrosis of the capillary endothelium, microthrombosis, ruptures and desolation of capillaries);
interstitial edema, hyperproduction of connective tissue fibers, thickening of the interalveolar septa;
necrosis of type I alveolar cells and metaplasia of type II alveolar cells, disruption of surfactant production, collapse of the alveoli;
development of type III immunological reaction (formation of antigen-antibody complexes).

Thus, in the development of toxic fibrosing alveolitis, the most important role is played by the direct toxic effect of drugs and harmful production factors on the lung tissue, as well as the development of an immunological reaction of type III. Ultimately, interstitial and intraalveolar pulmonary fibrosis develops.

Symptoms of toxic fibrosing alveolitis

The clinical picture of toxic fibrosing alveolitis, the data of X-ray examination of the lungs, spirography are similar to those in exogenous allergic alveolitis. The leading clinical sign is dyspnea, which becomes steadily progressive with continued exposure to the causative factor - a drug or industrial toxic substances. According to the course, three forms of toxic fibrosing alveolitis are distinguished - acute, podoetral and chronic. Their symptoms are the same as in exogenous allergic alveolitis.