Exposición a gas CS: a propósito de un caso peculiar / Exposure to CS gas: Case study

El gas CS (o-clorobenzolideno malononitrilo) se incluye dentro del grupo de los gases lacrimógenos. La exposición a dicho gas ocurre durante su empleo como gas de defensa o antidisturbios, así como durante el entrenamiento rutinario de las fuerzas de choque especializadas. Su acción tóxica es ejercida a través de un efecto irritante sobre piel y mucosas, así como por mecanismos inmunoalérgicos. Presentamos el caso de un paciente de 24 años, perteneciente a una fuerza de choque, que consultó por lesiones cutáneas luego de una exposición a humo y dispersión de polvo de una granada de gas CS durante ejercicios de entrenamiento. Clínicamente se presentó características peculiares, referidas a sus manifestaciones cutáneas, localización y severidad de las mismas. Se analiza la etiopatogenia de las lesiones y los posibles mecanismos involucrados, diagnósticos diferenciales, así como los pilares del tratamiento frente a una exposición a gas CS...

Acute laryngeal and bronchial obstruction after CS (o-chlorobenzylidenemalononitrile) gas inhalation.

CS gas (o-chlorobenzylidenemalononitrile) is one of the most commonly used riot agents. It can create excessive tearing, conjunctivitis, uncontrolled blinking (blepharospasm) and a sensation of burning and pain at initial exposure. Pulmonary edema (ARDS) and/or diffuse airway lesions on human would be lethal after CS inhalation. We report a case with acute laryngeal and bronchial obstruction due to vocal cord edema and extensive crusting at glottic level, trachea and bronchi. The CS gas was sprayed in a 6 x 6 m(2) closed room, and she was exposed to increased concentration of the gas for 10 s. Surprisingly, her initial symptoms were raised 21 days after CS spray exposure.

Unintended cutaneous reactions to CS spray.

CS spray (2-chlorobenzylidene malononitrile 5% w/v in methyl isobutyl ketone) has been used by the police force in the UK as an incapacitant for nearly a decade. It causes a number of well-recognized cutaneous reactions, which are generally regarded as short-lived. These include skin burning, erythema and blistering. However, a range of unpredictable cutaneous reactions to CS spray may also occur. We have found contact allergy, leukoderma, initiation or exacerbation of seborrhoeic dermatitis, and aggravation of rosacea following CS spray exposure in 6 police officers and 1 doorman. These skin reactions have required long-term changes in working practice for the affected individuals. Police officers may have repeated exposure to CS spray during their training and in their work, and designated police officers carry CS spray canisters daily in the line of duty. They may therefore be at greater risk of exposure to CS spray and its unintended effects than many assailants.

Acute pulmonary effects from o-chlorobenzylidenemalonitrile "tear gas": a unique exposure outcome unmasked by strenuous exercise after a military training event.

o-Chlorobenzylidenemalonitrile, more commonly called CS, is grouped with several other irritant agents referred to as "tear gas." It is a riot-control agent used frequently in military settings to test the ability and speed of personnel in donning their military gas masks. When personnel are exposed to CS without proper personal protective equipment, it has potent irritant effects. We report a unique cluster of hospitalizations of nine U.S. Marines who developed a transient pulmonary syndrome. All nine patients had symptoms of cough and shortness of breath. Five of the nine presented with hemoptysis, and four presented with hypoxia. Symptoms were associated with strenuous physical exercise from 36 to 84 hours after heavy exposure of CS in a field training setting. Four of the nine Marines required intensive care observation as a result of profound hypoxia. All signs and symptoms resolved within 72 hours of hospital admission. One week after CS exposure, all nine Marines demonstrated normal lung function during spirometry before and after exercise challenge using cycle ergometry.

Severe cutaneous reaction to CS gas.

Tear gas is used throughout the World for control of riots and civil disobedience. CS gas as used by the UK police force is issued as a 'spray' and is 5% CS in methylisobutylketone (MIBK), a potent irritant. Assaults on police officers in forces issued with CS spray have fallen significantly over the past 3 years, whilst having risen in areas without it. Thus, CS gas appears to be an effective deterrent. However, significant cutaneous reactions can occur as a result of exposure. We report a severe contact dermatitis to CS gas to highlight the clinical features. The nature of CS gas and potential cutaneous adverse reactions are discussed.

Medical hazards of the tear gas CS. A case of persistent, multisystem, hypersensitivity reaction and review of the literature.

A 30-year-old incarcerated man was sprayed with the "tear gas" ortho-chlorobenzylidene malononitrile (CS). He was hospitalized 8 days later with erythroderma, wheezing, pneumonitis with hypoxemia, hepatitis with jaundice, and hypereosinophilia. During the subsequent months he continued to suffer from generalized dermatitis, recurrent cough and wheezing consistent with reactive airways dysfunction syndrome, and eosinophilia. These abnormalities responded to brief courses of systemic corticosteroid but recurred off therapy. The dermatitis resolved gradually over 6-7 months, but the patient still had asthma-like symptoms a year following exposure. Patch testing confirmed sensitization to CS. The mechanism of the patient's prolonged reaction is unknown but may involve cell-mediated hypersensitivity, perhaps to adducts of CS (or a metabolite) and tissue proteins. This is the first documented case in which CS apparently caused a severe, multisystem illness by hypersensitivity rather than direct tissue toxicity. Both the ethics and safety of CS use remain controversial, in part because of the difficulty documenting sporadic injuries received in the field, and also because the charged circumstances surrounding CS use may lead to both underreporting and exaggerated claims of medical harm. The medical literature on CS focuses mainly on its immediate irritant effects and on transient dermal and ocular injuries, with only 2 prior case reports of acute lung injury related to CS exposure. Given the paucity of documented lasting effects despite its widespread use for more than 3 decades, CS appears to be safe when deployed (outdoors) in a controlled manner, but it can cause important injuries if misused or if applied to a sensitized individual.

Acute effects of the potent lacrimator o-chlorobenzylidene malononitrile (CS) tear gas.

1. The use of tear gas to control civil unrest is accepted practice by government authorities worldwide. It is rarely used in Hong Kong but during a recent riot at a Vietnamese detention centre large quantities were used and this was cause for some concern. 2. All patients presenting to the British Red Cross Clinic after the incident were seen by one of the authors. To establish if exposure to tear gas had serious effects on the health of the detainees, the case records of the 184 patients with symptoms consistent with CS exposure were reviewed 2 months later. 3. The most common complaints were burns (52%), cough (38%), headache (29%), shortness of breath (21%), chest pain (19%), sore throat (15%) and fever (13%). However, the only common findings on examination by a physician were burns (52%) and an inflamed throat (27%). All burns could be categorised as "minor' according to the American Burns Association classification and all were consistent with CS gas exposure. 4. Some patients complained of other symptoms that had not been previously reported in the literature, such as haemoptysis (8%) and haematemesis (4%), but these were only confirmed in one patient. 5. The majority of patients had recovered within 2 weeks of exposure although one asthmatic patient complained of shortness of breath lasting for 33 days and a sore throat lasting for 38 days after the incident. She had abnormally low peak expiratory flow readings, but had a clinical history of asthma. 6. No serious sequelae were encountered, but the incidence of burns in these patients was higher than would be expected from a review of the literature. However, very little data on the effects of tear gas in a riot situation has been published. There have been reports of high concentrations of CS gas causing reactive airways dysfunction but this was not seen in our group of patients.

Acute mass burns caused by o-chlorobenzylidene malononitrile (CS) tear gas.

The use of tear gas in controlling riots has been an accepted practice in many countries for the past four decades. In a recent event, a large quantity of tear-gas canisters were used during a situation of unrest in a Hong Kong Refugees' Detention Centre. We report 96 cases of acute burn injury as an unpredicted side effect of o-chlorobenzylidene malononitrile (CS) tear gas. There were 47 females and 49 males with an age ranging between < 1 to 51 years. These burns were categorized as minor burns, with the total body surface area (TBSA) ranging from 1 to 8 per cent with mean percentage of 3. Most of the patients sustained superficial or partial-skin thickness injuries. Only two patients were admitted to the Prince of Wales Hospital Burns Centre because of deeper burns; debridement and skin grafting was required in one of them. The mechanism of burn injury was due to the flame generated from the grenade explosion, direct contact between the hot canister and the victim's skin, and the effect of the chemical powder inside the canisters when it splashed onto the victim's body. We suggest that the noxious transient effects of tear gas are underestimated, furthermore varying cutaneous effects and deep burns may result from its uncontrolled use during riots. There is a continuing need to reassess the potential toxic effects of CS tear gas as a riot control agent and to debate whether its future use can be condoned under any circumstances.

CS gas--implications for the anaesthetist.

Although the use of CS gas is illegal in the UK, an occasional patient exposed to its effects may be seen. We report the problems experienced with the anaesthetic management of such a patient.

[Contact allergies to CN and CS ("tear gas") in participants in demonstrations]. / Zur Frage der Kontaktallergien auf CN and CS ("Tränengas") bei Demonstrationsteilnehmern.

56 occasional demonstrators were interviewed with regard to former skin contact with omega-chloroacetophenone (CN) or ortho-chlorobenzylidene malononitrile (CS). 33 persons (59%) reported skin reactions of various kinds. Patch testing with CN, the structurally related preservative chloroacetamide, and CS revealed clinically relevant reactions to CN in 3 cases and questionable positive reaction to CS in one case. 8 further patients showed mild reactions to CN and CS. We did not find any indication of cross reactions between CN and chloroacetamide.