Approach Considerations
The diagnosis of acute chlorine toxicity is primarily clinical, based on respiratory difficulties and irritation. However, laboratory testing is useful for monitoring the patient and evaluating complications. Studies in patients with significant exposure to chlorine gas may include the following:
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Pulse oximetry
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Serum electrolyte, blood urea nitrogen (BUN), and creatinine levels
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Chest radiography
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Electrocardiogram (ECG)
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Ventilation-perfusion scan
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Pulmonary function testing
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Laryngoscopy or bronchoscopy
Abnormalities include hypoxia (from bronchospasm or pulmonary edema) [1] and metabolic acidosis, which may be a hyperchloremic (nonanion gap) acidosis. [7] It is postulated that this may be caused by the absorption of hydrochloric acid following the reaction of chlorine gas with mucosal water. [24, 32]
Handheld peak flow meters can be used to measure the degree of bronchospasm and follow the response to treatment. Pulmonary function tests may indicate obstructive or restrictive patterns and can provide measurements of the degree of limitation.
Biomarkers
In a study that screened for chlorinated biomolecules by the use of mass isotope ratio filters, two biomarkers present in bronchoalveolar lavage fluid (BALF) from chlorine gas exposed mice were identified. The potential chlorine specific markers were all chlorohydrins of unsaturated pulmonary surfactant phospholipids; phosphatidylglycerols, and phosphatidylcholines. The relevance of these markers for human exposure was verified by their presence in in vitro chlorinated human BALF. The biomarkers were detectable for 72 h after exposure and were absent in nonexposed control animals or in humans diagnosed with chronic respiratory diseases. [3]
Chest Radiography
The chest radiograph findings are frequently normal initially but may exclude other causes of hypoxia in the differential. Abnormalities may nonspecific; however, pulmonary edema, pneumonitis, [33] and adult respiratory distress syndrome (ARDS) may be seen in some cases. The radiograph below shows diffuse pulmonary edema without significant cardiomegaly.
Chest radiograph of a 36-year-old chemical worker 2 hours postexposure to chlorine inhalant. She had severe resting dyspnea during the second hour, diffuse crackles/rhonchi on auscultation, and a partial pressure of oxygen of 32 mm Hg breathing room air. The radiograph shows diffuse pulmonary edema without significant cardiomegaly. Used with permission from Medical Aspects of Chemical and Biological Warfare, Textbook of Military Medicine. 1997: 256.
CT scan of the chest can reveal the extent of interstitial pulmonary edema.
A ventilation-perfusion scan showing abnormal retention of radiolabeled xenon gas at 90 seconds suggests lower airway injury.
Histologic Findings
The image below shows a sample of lung tissue obtained from biopsy of a patient with exposure to chlorine.
A section from a lung biopsy (hematoxylin and eosin stain; original magnification X 100) from a 36-year-old chemical worker taken 6 weeks postexposure to chlorine. At that time, the patient had no clinical abnormalities and a partial pressure of oxygen of 80 mm Hg breathing room air. The section shows normal lung tissues without evidence of interstitial fibrosis and/or inflammation. Used with permission from Medical Aspects of Chemical and Biological Warfare, Textbook of Military Medicine. 1997: 256.
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Chest radiograph of a 36-year-old chemical worker 2 hours postexposure to chlorine inhalant. She had severe resting dyspnea during the second hour, diffuse crackles/rhonchi on auscultation, and a partial pressure of oxygen of 32 mm Hg breathing room air. The radiograph shows diffuse pulmonary edema without significant cardiomegaly. Used with permission from Medical Aspects of Chemical and Biological Warfare, Textbook of Military Medicine. 1997: 256.
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A section from a lung biopsy (hematoxylin and eosin stain; original magnification X 100) from a 36-year-old chemical worker taken 6 weeks postexposure to chlorine. At that time, the patient had no clinical abnormalities and a partial pressure of oxygen of 80 mm Hg breathing room air. The section shows normal lung tissues without evidence of interstitial fibrosis and/or inflammation. Used with permission from Medical Aspects of Chemical and Biological Warfare, Textbook of Military Medicine. 1997: 256.
