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CHAPTER 4 - Continued

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BLISTER AGENTS (VESICANTS)

4-29. Eye Injuries

a.    Sensitivity to Mustard. The eye is more sensitive and more vulnerable to the action of mustard than any other part of the body. About 86 percent of the mustard casualties in World War I had eye lesions to some degree. Exposure for 2 hours to a concentration of mustard, barely perceptible by odor, will produce eye lesions but may not affect the respiratory tract or the skin. There is no immediate symptomatic or local reaction to the absorbed agent. A latent period (which varies with the degree of exposure) precedes the onset of symptoms. This period ranges from 4 to 12 hours after mild exposure and 1 to 3 hours after severe exposure.

b.    Classification of Lesions of the Eyes. Eye lesions produced by mustard are divided into the following types.

(1)    Mild. Of all the cases in World War I, 75 percent had mild burns of the eyes. The mild symptoms include itching, lacrimation, and a sensation of grit in the eye, followed by burning and sometimes by photophobia. There is a hyperemia of both the palpebral and bulbar conjunctivae. The reaction in the latter usually begins as a band-shaped area running transversely across the eye with normal white bulbar conjunctiva above and below it. Edema of the lids may also be present. Hospitalization is seldom required and recovery occurs in 1 to 2 weeks. Such cases are not classified as casualties.

(2)    Moderate. p> (a)   In this group there is complete closure of the eyes from a combination of spasm and swelling of the lids about 3 to 6 hours after exposure. Blepharospasm and blurring of vision develop. There is marked hyperemia and edema of the conjunctiva with a prominent interpalpebral band, edema of the lids, mild iritis, and edema of the epithelium of the cornea producing a roughened appearance like that of an orange peel. The blepharospasm and edema of the lids may be too severe to enable the patients to open their eyes and, so, they may believe they are blind. Miosis occurs early.

(b)   A mucoserous discharge is usually present and, although sterile in the early stage, it may cause the lids to stick together, resulting in accumulation of secretions in the conjunctival sac and predisposition to infection. Personnel in this condition are temporarily blind and will be evacuated as casualties. Early and prolonged hospitalization is required, with transfer to the care of an ophthalmologist when possible. Recovery occurs in 1 to 6 weeks, usually without loss of vision. Return to duty will depend upon the extent of residual corneal injury, photophobia, and blepharospasm.

(3)   Severe.

(a)   In this group the latent period is short, lasting 1 to 3 hours. There is deep ocular pain and headache, both of which may be severe, in addition to severe blepharospasm and blurred or dimmed vision. There is marked hyperemia and edema of the conjunctiva with a blanched area of ischemic necrosis in the interpalpebral portion, chemosis, and edema of the lids, which the patient cannot open. The epithelium and stroma of the cornea are damaged. Surface epithelium is hazy in the early stage and will stain extensively or, in a punctate manner, with fluorescein within 24 hours. After 24 to 48 hours there is also edema of the stroma of the cornea and a deeper haze becomes apparent. Iritis and mucoserous discharge are also present. If the damage is progressive, there may be dense corneal opacification with deep ulceration and vascularization from the limbus. The cases with corneal ulcer heal slowly and may have relapses, some may present perforations into the anterior chamber. These casualties require hospital care and should be evaluated at the earliest possible moment.

(b)   Droplets of a liquid blister agent contaminating the eye may produce similar effects. One eye alone may be involved or may be affected more severely than the other. In contrast to droplets of mustard alone, droplets of L or mixtures of L and mustard cause immediate, painful spasm of the lids.

(c)   In disposing of eye casualties, medical officers must assure themselves that mild symptoms will not develop into severe inflammation and temporary blindness within a few hours. Reference to time of exposure and rate of development of symptoms will guide them. If the effects are increasing rapidly, it is advisable to evacuate the case in anticipation of development of disability within the next few hours. Symptoms usually reach a maximum within 6 to 12 hours following exposure.

c.    Disposition. The correct disposition of personnel with eye lesions caused by blister agents is less of a problem to the medical officer than those with lesions involving the trunk and limbs. Several hours following exposure of the eyes to mustard, it may be possible to determine whether personnel can remain on duty or will require evacuation.

4-30. Effects on the Respiratory System

a.    Circumstances of Exposure. Most respiratory lesions are the result of prolonged exposure to relatively low concentrations of vapor. Severe casualties may result from unrecognized exposure to strong concentrations of mustard vapor. A fatiguing effect on the sense of smell may follow exposure to low concentrations of mustard, thus minimizing detection. Severe lesions occur in individuals who cannot mask, such as unconscious casualties and those with severe injuries to the face or upper extremities.

b.    Latent Period. The effects of exposure upon the respiratory tract are characterized by a long latent period before the onset of symptoms, 18 to 36 hours intervening. Because the eyes are more sensitive to the agent than the nasal mucosa but are exposed simultaneously, respiratory effects should be expected to follow vapor burns of the eyes (and face) in unmasked personnel.

c.    Mucous Membranes. The local action of mustard vapor on skin and eyes is matched by a similar effect on the mucous membranes of the respiratory tract. Most of the inhaled vapor is absorbed in the larger respiratory passages, including the bronchi, and very little remains to injure the pulmonary parenchyma.

d.    Nose. In the nose the earliest visible effect is hyperemia and edema of the mucosa. This is associated with a profuse, thin, mucopurulent discharge. Degenerative changes in the epithelium, varying in degree according to the extent of exposure, range from small discrete ulcerations to extensive sloughing. Nosebleeding is rare. Nasal injury seldom occurs alone and, as such, is usually a cause for hospitalization.

e.    Pharynx. Acute inflammation of the pharynx usually appears 1 to 3 days after exposure to mustard vapor, although there may be a delay of as much as a week. There is mild dryness and soreness of the throat, aggravated by swallowing but rarely accompanied by regional lymphatic enlargement. Pharyngeal and laryngeal lesions may develop without significant nasal involvement, especially in mouth breathers. Upon inspection, the palate, uvula, tonsils, and pharynx are swollen. Multiple whitish ulcerations may appear, varying in size according to the severity of exposure. Pharyngeal injury is unlikely to occur alone. Secondary infection generally results in regional adenitis.

f.    Larynx. Laryngeal involvement commonly results from inhaling mustard vapor, the lesions resembling those of the pharynx. Hoarseness, sometimes progressing to loss of voice, may last 3 to 6 weeks, and in rare instances, longer. This type of lesion alone may not require hospitalization, but it is almost invariably associated with more extensive injury to the respiratory tract.

g.  Trachea and Bronchi. In the trachea and bronchi, a similar necrotizing and inflammatory process follows contact with mustard vapor. The exudative process results in the formation of a fairly thick, tenacious pseudodiphtheritic membrane in the larynx, trachea, and large bronchi. It may form a cast of the involved parts sufficient to prove fatal. This condition requires early hospitalization. Milder cases, however, have small ulcerations with hyperemia and edema of the mucosa and hypersecretion of mucous. Res�piratory embarrassment, cough, tachypnea, and cyanosis are signs warranting prompt hospitalization.

h.    Pulmonary Parenchyma. The action of mustard on the lung may cause chemical pneumonitis. Secondary infection may lead to lobular or lobar consolidation, the course being dominated by the characteristics of the type of pneumonia. Injury due to mustard in no way affects the treatment of the secondary infection. Antibiotics and supportive measures should be used as appropriate.

4-31. Cutaneous Burns

a.    Evaluation of Cutaneous Burns. The following observations resulted from evaluation of lesions that have most generally led to disability of personnel exposed to blister agents during field trials and then participated in simulated combat exercises, obstacle course tests, and marches.

(1)    Widespread vesication of the trunk produced casualties.

(2)    Vesication localized in particular areas of the body produced casualties.

(3)    Burns produced by high doses of the blister agent vapor to masked personnel (especially in tropical climates) cause severe casualties. These casualties are produced partly by edema and vesication of the skin and partly by constitutional reactions such as nausea, vomiting, and prostration.

(4)    Burns produced by doses of vapor low enough to cause only such skin reactions as mild erythema, edema, burning, and itching usually do not produce casualties.

(5)   The stage of development of the lesion must be considered when classifying an individual as a casualty or noncasualty.

b.    Trunk and Neck.

(1)    Extensive vesication of the trunk. All the cases considered under this heading should be evacuated promptly.

(a)   Extensive vesication may occur over a large part of the trunk. Intervening areas of skin may be erythematous with pinpoint vesication. These burns are more likely to occur on the back than anteriorly. Some protection is afforded anteriorly by equipment such as webbing and ammunition pouches. The front of the uniform also gives some anterior protection because it does not cling to the body.

(b)    Extensive vesication may be followed by fever, nausea, and vomiting. These conditions tend to occur more readily in tropical climates.

(c)    Secondary bacterial infection may complicate the clinical course. The medical officer in a forward position is not likely to see infection of vesicated areas because such cases will have been evacuated before secondary infection develops.

(2)    Localized vesication of the trunk.

(a)    Vesication occurring within the natal cleft (between the buttocks) usually requires evacuation of the casualty. Walking becomes difficult, defecation is painful, and dressings require frequent changing. The lesion is usually most intense at the upper end of the cleft. Vesication of the buttocks usually results from sitting on contaminated ground or wearing contaminated trousers for prolonged periods. The vesicated area may extend forward across the perineum to involve the scrotum and the penis.

(b)   Trivial burns, such as mild erythema affecting the natal cleft, are not of casualty severity. However, these burns require careful attention because walking or running aggravates the lesions and may break down injured skin.

(c)   Single discrete blisters on the buttocks away from the natal cleft do not produce casualties.

(d)   Blisters on the trunk generally require protective dressings to avoid friction of clothing. Medical officers must decide whether or not dressings should remain in position during regular duty.

c.    Burns Caused by High Doses of Vapor. After exposure to a high dose of mustard vapor, especially under tropical conditions, nausea, vomiting, and symptoms of collapse are usually evident before erythema completely develops. It is important to note that this occurs also among personnel who are masked during exposure. Constitutional symptoms may persist several days, during which burns will increase in severity. Cases of this type should be classed as casualties. Severe vapor burns of the trunk give a generalized erythema but include pale gray areas that eventually vesicate or become necrotic. It is common to see patches of unaffected skin as a result of protection by overlying equipment.

d.    Burns Caused by Low Doses of Vapor. Mild vapor burns cause erythema, itching, and irritation but do not produce casualties. The medical officer should always consider the interval after exposure in relation to the severity of the burn. Mild lesions may represent early phases of severe exposure to vapor. When the period of lapse since exposure is uncertain, rapid development and presence of constitutional symptoms may help to determine the severity.

e.    Sensitization Due to Multiple Exposures to Mustard. p> (1)    Watch for the characteristic appearance of �reexposure� burns. This manifestation may occur in individuals as a result of exposure to mustard 1 to 3 weeks (or more) previously. A small percentage of these casualties will become sensitized to the agent and will react differently, both qualitatively and quantitatively, upon reexposure.

(2)    Sensitization will be followed by a more rapid onset of symptoms upon reexposure. Erythema, with or without edema, and pronounced itching and burning usually appear within 1 hour. Lower concentrations of mustard are required to produce effects in a sensitized individual than in a nonsensitized. When erythema and edema result from exposure to a low dose, they generally develop rapidly and subside within 2 to 3 days. Also, vesication heals more rapidly in the sensitized individual.

(3)    One of the most frequent manifestations of reexposure in sensitized personnel is the development of a morbilliform rash. Another characteristic reaction is the appearance of eczematoid dermatitis surrounding old lesions, whether or not they are healed. This may last for several days and resembles dermatitis venenate (from poison ivy). Similar phenomena due to sensitization have been known to occur with L and with the nitrogen mustards.

f.    Arms.

(1)    After treatment, most service members with blister agent injuries of the arms are permitted to continue with their duties. Vesication, when localized, produces little or no disability.

(2)    Extensive vesication involving the axillae and the elbows, volar or dorsal aspects, partially impairs the movement of the limbs at those joints. Edema of the surrounding tissue tends to further immobilize the extremities. The dorsal aspects of the elbow and forearm are common sites of severe burns because these parts touch contaminated ground when service members are firing in the prone position. Cases of this type should be evacuated.

(3)    Widespread vesication of the arms results in partial disability. Cases of this type should be evacuated.

g.    Hands.

(1)    Blister agent burns of the hands are often encountered. These burns tend to cause a degree of disability out of proportion to the size of the lesions. Considerable care and judgment are required in correct disposition.

(2)    The palms are more resistant to vesication but not entirely. Blisters affecting the palms are characteristically painful and slow to heal.

(3)    A solitary lesion of limited extent may result in little or no disability if treated properly.

(4)    Burns from liquid vesicant on the dorsum of the hand result in severe local reactions characterized by intense edema of the backs of the hands and fingers. Pain is characteristic and is intensified by movement of the fingers or wrist. These cases should be regarded as casualties. An individual exposed within the previous 24 hours and reporting for treatment, with apparently tribal blisters, may be totally incapacitated the following day. Sharp erythema of the dorsum of the hand, with beginning vesication 12 to 24 hours after exposure, indicates a lesion that will progress to extensive vesication and edema. Under such circumstances, the individual should be evacuated when first seen.

(5)    More commonly, the lesions consist of scattered small vesicles and limited areas of erythema. These lesions can be protected satisfactorily and the individuals returned to duty.

(6)    Exposure to vesicant vapor produces diffuse erythema of the dorsum of the hand and wrist. Higher doses cause edema and vesication as well; cases of this type require evacuation.

h.    The Lower Extremities.

(1)    When the lower extremities are involved, the knees are the most common sites of burns from liquid vesicant. These lesions and those of the ankles often result in incapacitation by interfering with locomotion. Movement of the joints tends to aggravate existing lesions by increasing edema. A further disabling factor is introduced by the wearing of firm dressings applied to mobile joints.

(2)    Vesication often spreads over the kneecaps, upward onto the thighs, and down toward the feet. These burns tend to be extensive and are associated with edema often extending halfway up on the thigh and down the leg. Medical officers should evacuate casualties presenting such lesions.

(3)    In general, burns of the leg are more incapacitating than burns of the thigh.

(4)   It has been shown that the presence of many superficial blisters on the legs and thighs alone is not enough to make a service member incapable of carrying out routine military duties. Individuals with such lesions, having protective dressings, were able to take part in daily marches and routine gun drills. In disposing of these cases, the medical officer will consider the mental and physical status of these individuals, their motivation, their military occupational specialty, and the tactical situation at the time. Such cases are in the category of partial disability. After suitable dressings have been applied, service members with high morale and robust physiques may be returned to duty.

(5)    A relatively small blister or group of blisters situated in the popliteal area may reduce the efficiency of service members so much that they may require evacuation. This is due to aggravation of the lesions by movement of the limbs and interference with ambulation. However, blisters affecting this area are not necessarily casualty producing. (Inflammation, edema, infection, and lesions on other parts of the body should be considered when deciding upon the disposition of an individual.) Available evidence indicates that the mustard blister, size for size, is potentially more incapacitating than a blister from L. This results from the tendency of mustard blisters to be associated with erythema and edema, while the L blisters usually cause less local reaction.

(6) Vesicant lesions develop also near the ankles at the tops of the shoes. Blistered areas occurring at such unprotected points are associated with severe pain due to circulatory impairment and tense edema of the leg. These cases should be evacuated.

(7)    Vapor burns of the legs tend to be most aggravated in the popliteal spaces. Pinpoint vesication is often found here. Higher doses cause intense erythema with scattered areas of vesication over the entire surface of the leg. Such lesions are invariably casualty producing and are generally accompanied by severe burns elsewhere, frequently with severe systemic effects.

(8)    Mild vapor burns of the legs produce irritation and itching common to all widespread vapor burns. While these effects are troublesome, they are not casualty producing. Service members with mild vapor burns should be returned to duty.

(9)   Extensive vesication of the feet is uncommon. The soles are protected by shoes and are more resistant to vesication. Burns on the dorsal aspect of the foot are often associated with local reactions like those seen on the backs of the hands. Individuals with these burns, especially if widespread over the foot, find it difficult or impossible to wear shoes and will require evacuation. Small discrete blisters may be of noncasualty significance. These blisters may be effectively protected so as to allow wearing of shoes and walking with little discomfort.

i.   The Genitalia.

(1)    The genital region, in addition to the eyes and the respiratory tract, is highly sensitive to blister agent burns. In World War I such burns produced many casualties. The majority of these burns were caused by vapor. Despite present methods of protection against blister agents, medical officers (especially in tropical areas) may be confronted with many such burns.

(2)   Vapor is a more common cause of burns affecting the male genitalia than a liquid agent. Erythema may not be conspicuous. The most prominent feature of the burn is the edema involving the penis and scrotum. Fluid accumulates most readily in the prepuce, distending its entire circumference and forming a characteristic semitranslucent ring around the corona. In more severe cases, the entire body of the penis becomes edematous. Female genitalia are affected in a similar manner, the most prominent feature being edema of the labia. In severe burns, fluid may also accumulate in the labia.

(3)    These lesions cause apprehension as well as physical discomfort. Occasionally, vesication is superimposed on the edema. Spotty ulceration is not infrequent at the tip of the prepuce where it may become secondarily infected. In severe cases associated with marked edema, retention of urine may result from both mechanical and reflex effects.

(4)    In mild cases, objective changes of the scrotum often tend to pass undetected due to the normal pigmentation, elasticity, and looseness of the skin. Even considerable edema may not be enough to reveal its presence. In severe cases the scrotum may become grossly enlarged. The rugae may be partly or completely obliterated. Pinpoint vesication may occur, usually after a lapse of a few days. The scrotum tends to break down resulting in small, painful ulcers and fissures.

(5)    Burning is the most prominent subjective symptom in involvement of the genitalia. Apprehension and anxiety are distressing during the presence of the objective changes described in (3) and (4) above. As edema decreases, itching starts and may persist long after the acute effects have subsided. Sometimes this itching is intolerable. The scrotum may continue to crack and ulcerate for a considerable period, causing pain and irritation.

(6)    Mild exposure of the genital region typically is followed by a delay in the development of symptoms, often for as long as 4 to 10 days.

(7)    Patients with mild burns without edema or vesication, but who complain of irritation and burning, may be safely returned to duty following treatment. In disposing of mild burns of the genitalia, medical officers must assure themselves that the symptoms are not too early to be judged with finality. Severe cases should be evacuated on the basis of the apprehension that may be suffered as well as the physical discomfort involved.

j.    Systemic Effects of Cutaneous Burns.

(1)    Severe systemic effects due to blister agents probably will be encountered only with disabling skin lesions. The medical officer should be familiar with the signs and symptoms. These include anorexia, nausea, vomiting, depression, and fever, and are far more prone to occur in hot than in temperate climates. Malaise and nausea generally are the first reactions and may progress either to mild, transient vomiting or to severe, persistent vomiting and retching. Anorexia may be the only complaint in mild reactions. The actual time of onset of symptoms is 4 to 12 hours after exposure, and symptoms often occur before skin injury is manifest. No rule can be given for the duration of systemic symptoms, although casualties usually have recovered from severe vomiting within 24 to 36 hours. Anorexia and nausea may persist for a longer time.

(2)    The temperature may remain elevated for several days. Mental depression may follow mustard burns and persist for several days.

(3)    Service members with systemic reactions will generally be casualties, particularly in view of the probability of associated extensive skin burns. Such cases should be evacuated quickly.

k.   Secondary Bacterial Infection in Blister Agent Burns. This paragraph considers the problem of secondary bacterial infection after blister agent injuries only as it influences the disposition of affected personnel in forward positions. For management and treatment of such cases, see sections II through IV.

(1)    Secondary bacterial infection may result if adequate wound care is not given. Compared to the incidence of infection in thermal and traumatic wounds, the incidence of sepsis in mustard lesions is remarkably low, according to observations made at experimental installations.

(2)    Secondary infection becomes manifest several days after injury. Medical officers are not likely to see secondary infection with extensive blister agent burns in the front lines because severe cases will have been evacuated early.

(3)    Infection of small lesions does not require evacuation. Infection of multiple lesions is likely to be an indication for evacuation, particularly if constitutional effects are associated. Infection is particularly disabling when it involves the feet,hands, genitals, or tissue overlying the joints of the limbs.

(4)    Secondary infection is more likely to occur in severe, rather than mild, vapor injury to the respiratory tract. Severe respiratory symptoms will almost always be associated with severe eye effects. Respiratory lesions may not develop for several days, and by then the individual should have been evacuated as an eye casualty.

(5)    Secondary infection is uncommon as a sequel to mild degrees of mustard conjunctivitis and ordinarily would not prevent an individual from continuing duty.

(6)    Mild conjunctival burns may be associated with pharyngitis, laryngitis, and tracheitis, increasing in severity for several days. Occasionally, more extensive respiratory infection may ensue.