Peribronchial fibrosis

Acute poisoning may result from inhalation of cadmium dusts and fumes (usually cadmium oxide) and from the ingestion of cadmium salts. The major toxic effects are due to local irritation. In the case of oral intake, these include nausea, vomiting, salivation, diarrhoea and abdominal cramp. Cadmium is more toxic when inhaled. Signs and symptoms, which appear after a few hours, include irritation of the upper respiratory tract, chest pains, nausea, dizziness and diarrhoea. Permanent lung damage may occur in the form of emphysema and peribronchial and perivascular fibrosis. Death is usually due to massive pulmonary oedema. 

Guinea pig Inhalation 67 6 h/d for 5 d Mild bronchitis with some peribronchial fibrosis. No deaths. Machlc et al. 1942... 

Figure 1 Small airways in COPD patients. The airway wall is thickened and infiltrated with inflammatory cells, predominately macrophages and CD8+ lymphocytes, with increased numbers of fibroblasts. In severe COPD, lymphoid follicles are observed, which consist of a central core of B-lymphocytes, surrounded by T-lymphocytes and are thought to indicate chronic exposure to antigens (bacterial, viral, or autoantigens). Similar changes are also reported in larger airways. The lumen is often filled with an inflammatory exudate and mucus. Peribronchial fibrosis occurs, and it results in progressive and irreversible narrowing of the airway. Airway smooth muscle may be increased slightly.

Toxicity on Lung. Experimental studies in animals have shown that W metal, tungsten carbide, and tungsten carbide-carbon alloy are not very toxic [29-33]. On the other hand, inhalation of tungsten-carbide-cobalt alloy in guinea pigs induces an inflammatory reaction accompanied by peribronchial fibrosis and bronchial mucosa hypertrophy [31,32]. 

In 20 women and 8 men from Seoul, Korea, ranging in age from 42 to 86 years (median, 64 years) not occupationally exposed to coal dust or other soot particles complaining of cough and dyspnoea on exertion, pathologic study of the lesion obtained by bronchoscopic biopsy or thoracotomy showed dense bronchial and/or peribronchial fibrosis with interspersed black pigments (Chung et al. 1998). Marked perivascular fibrosis and several foci of pe-... 

Fig.7.12a,b. (a) In vitro thin-section computed tomography scan of inflated and fixed lung. Subpleural dots and branching structures (arrows) are demonstrated, (b) Photomicrograph of same area shows peribronchial fibrosis (haematoxylin-eosin stain). Reproduced with permission from Akira et al. (1991)... 

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