Paraquat, lung damage

Child, 6-year-old, accidently swallowed unknown amount of Gramoxone W (contains paraquat) Residue in urine 6 days after exposure was 3.6 mg paraquat/L death 7 days after onset of symptoms. Autopsy showed ulceration of buccal mucosa, emphysema, severe lung damage, jaundice, and renal failure (Campbell 1968)... 

Frank, L., K. Neriishi, R. Sio, and D. Pascual. 1982. Protection from paraquat-induced lung damage and lethality in adult rats pretreated with clofibrate. Toxicol. Appl. Pharmacol. 66 269-277. 

Giulivi C, Lavagno CC, LucesoU E, Bermudez MJN, Boveris A (1995) Lung damage in paraquat poisoning and hyperbaric oxyen exposure Superoxide-mediated inhibition of phospholipase A2. Free Radic Biol Med 18 203-213 Goho A (2004) Science News Online 166, 14... 

Other types of lung damage may also lead to fibrosis, however, such as that caused by paraquat. 

Although the mammalian toxicity of paraquat is not high (LD50 150 mg kg-1, rat oral) it causes irreversible lung damage when it is ingested and it is this that has led to accidental fatalities. 

If it is inhaled, paraquat could cause poisoning leading to lung damage. In the past, some marijuana in the United States has been found to contain paraquat. 

Paraquat has received considerable attention because it was used to spray illegal poppy and marijuana fields in Mexico and elsewhere, which caused drug users to suffer lung damage from residual paraquat. 

The result of this is accumulation of phospholipids, or phospholipidosis, in the tissues where accumulation of the drug occurs. Active uptake of a toxic compound into the target tissue may also occur. For example, the herbicide paraquat is actively accumulated in the lung, reaches toxic concentrations in certain cells, and then tissue damage occurs (see chap. 7). 

Organ/tissue specificity. Particular tissues and organs may be damaged by chemicals because of uptake mechanisms, other biochemical/physiological characteristics or metabolic capabilities. For example, the lung is susceptible to paraquat because of an uptake mechanism (see chap. 6). 

The resulting lipid peroxides, if not detoxified, may give rise to lipid radicals and membrane damage. However, although there is experimental evidence that paraquat causes lipid peroxidation, there is little direct evidence from in vivo studies. This may reflect the fact that only a small proportion of lung cells are affected. 

Chemicals which can damage (a) the liver include carbon tetrachloride, paracetamol, bromobenzene, isoniazid, vinyl chloride, ethionine, galactosamine, halothane, dimethyl-nitrosamine (b) the kidney include hexachlorobutadiene, cadmium and mercuric salts, chloroform, ethylene glycol, aminoglycosides, phenacetin (c) the lung include paraquat, ipomeanol, asbestos, monocrotaline, sulfur dioxide, ozone, naphthalene (d) the nervous system include MPTP, hexane, organophosphoms compounds, 6-hydroxydopamine, isoniazid (e) the testes include cadmium, cyclophosphamide, phthalates, ethanemethane sulfonate, 1,3-dinitrobenzene (f) the heart include allylamine, adriamycin, cobalt, hydralazine, carbon disulfide (g) the blood include nitrobenzene, aniline, phenyl-hydrazine, dapsone. 

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