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Affiliation
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Department of Plastic Surgery, George Eliot Hospital, Nuneaton, Warwickshire, UK |
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Abstract
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2-Chlorobenzylidene malononitrile (CS) was developed in 1928 by Corson and Stoughton. It replaced chloroacetophenone (CN) as riot control agent and self-defence spray in the late 1950s due to its increased potency but more importantly, less toxicity. It is the most widely used form of 'tear gas'. The British Police force have used it since its introduction in March 1996 and use a 'spray' containing 5% CS (w/v) in a solvent of methylisobutylketone (MIBK) with a nitrogen propellant.
Advocates of its use claim, that if used correctly, the noxious effects are transient, and mainly manifest as lacrimation and irritation respiratory tract. Generally CS sprays appear to be safe if used in a controlled manner. We present a case of facial and upper body chemical burns resulting from the use of CS spray in the UK.
The police restrained a 24-year-old man after a domestic disturbance in the early hours of the morning. CS was sprayed onto the face and upper body and then the man was handcuffed. After release from police custody, he presented himself to his local Accident and Emergency Department the following evening complaining of burns to his face and upper body as well as pain in the shoulders and wrists related to his arrest.
CS is a white solid with a low vapour pressure that is released as an aerosol of fine particles or in solution. The microscopic particles act as potent sensory irritants, especially on moist skin and mucous membranes. It is an alkylating agent and reacts at nucleophilic sites. Although unclear, injuries related to this class of agents may be caused by the inactivation sulphhydryl-containing enzymes such as lactate dehydrogenase and coenzymes in the pyruvate decarboxylase system.4
Onset of symptoms usually occurs in the first minute after exposure with severe pain in the eyes and sensitive areas of the face. This is followed by lacrimation, visual disturbance, blephorospasm, rhinorrhoea, sneezing, coughing, retching, tightness in the chest and a burning sensation in the nose, throat and exposed skin. The severity of reaction depends upon the duration of exposure, concentration of the CS, moistness of the skin and whether the patient is in a restricted environment. The effects are usually temporary (reduced if in an 'open' environment) resolving in 30 min.
Severe burns related to CS exposure have been attributed to flame burns from the explosion of gas-grenades, contact burns when hot canisters touched victims' bodies, burns related to the MIBK solvent which in itself is an ocular and skin irritant, and delayed cutaneous hypersensitivity reactions related to previous exposure.3
In this case report, the most likely cause is a combination of the CS and MIBK resulting in a chemical burn. The confined environment and perspiration associated with the domestic dispute sought to aggravate the physiological response.
Following exposure to CS patients should be well aerated, and contaminated clothes removed. In the UK, blowing dry air from a hair dryer to force evaporation is the preferred method for facial exposure,5 while irrigation with normal saline to the rest of the body can be used.1 CS is known to have other serious toxic side effects such as miscarriage, hepatitis, pneumonitis and reactive airway dysfunction syndrome (recurrent cough and wheezing).2
Use of CS in a confined space is not advised due to the increased risk of severe toxic reaction. |