Medical Aspects of Chemical Warfare (2008) - The Black Vault

Medical Aspects of Chemical WarfareEXHIBIT 5-3CASE REPORT: EXPOSURE OF THREE MENTO SARINThree men [who worked at Edgewood Arsenal,Edgewood, Maryland], ages 27, 50, and 52 years,were brought to the emergency room because ofsudden onset of rhinorrhea and slight respiratorydiscomfort. At the onset of symptoms they wereworking in a large room in which some containers ofsarin were stored. Although there were other workersin the room, the three patients were together atone end where a leak was later found in one of thecontainers.On examination all three patients had essentially thesame signs and symptoms: very mild respiratorydistress, marked miosis and slight eye pain, rhinorrhea,a moderate increase in salivation, and scatteredwheezes and rhonchi throughout all lung fields. Noother abnormal findings were noted.All three patients reported that their respiratorydistress had decreased since its onset about 20 minbefore they arrived at the emergency room. The menwere kept under observation for the next 6 hr, butno therapy was administered. They continued toimprove and at the time of discharge from the wardthey were asymptomatic except for a slight irritationin the eyes and decreased vision in dim light.The patients were seen the next day and at frequentintervals thereafter for a period of four months. Eachtime they were seen, their [blood cholinesterase activities(both erythrocyte cholinesterase and butyrylcholineesterase)] were measured . . . and photographswere taken of their eyes [see Figure 5-4]. The firstphotographs were taken the day of the exposure,but the patients were not dark adapted. On each visitthereafter a photograph was taken by electronic flashafter the man had been in a completely dark roomfor 2 min. . . . About 60-70% of the lost ability to darkadapt returned in two weeks, but complete recoverytook two months.Reproduced with permission from: Sidell FR. Soman andsarin: clinical manifestations and treatment of accidentalpoisoning by organophosphates. Clin Toxicol. 1974;7:1–17.mechanisms may have equal or greater importance. Inthe case of the carbamate physostigmine, an increasein light sensitivity (a decreased threshold) after intramuscular(IM) administration of the drug has beenreported. 61 Carbamates may differ from nerve agentsin their effects on vision.Regardless of its cause, reduction in visual sensitiv-ity impairs those who depend on vision in dim light,individuals who watch a tracking screen, monitorvisual displays from a computer, or drive a tank inthe evening. Anyone whose vision has been affectedby exposure to a nerve agent should not be allowedto drive in dim light or in darkness.Visual AcuityIndividuals exposed to nerve agents sometimescomplain of blurred as well as dim vision. In onestudy, 62 visual acuity was examined in six subjectsbefore and after exposure to sarin vapor at a Ct of 15mg/min/m 3 . Near visual acuity was not changed inany of the subjects after exposure and was worsenedafter an anticholinergic drug (cyclopentolate) wasinstilled in the eyes. Far visual acuity was unchangedafter sarin exposure in five of the six subjects and wasimproved in the sixth, who nonetheless complainedthat distant vision was blurred after sarin.Two presbyopic workers who were accidentallyexposed to sarin had improved visual acuity for daysafter exposure. As the effects of the agent decreased,their vision returned to its previous state, which tookabout 35 days. 55 The author suggested, as others havepreviously, that miosis accounted for the improvementin visual acuity (the pinhole effect).Eye PainEye pain may accompany miosis, but the reportedincidence varies. A sharp pain in the eyeball or an achingpain in or around the eyeball is common. A mildor even severe headache (unilateral if the miosis isunilateral) may occur in the frontal area or throughoutthe head. This pain is probably caused by ciliary spasmand is worsened by looking at bright light, such as thelight from a match a person uses to light a cigarette(the “match test”). Sometimes this discomfort is accompaniedby nausea, vomiting, and malaise.Local instillation of an anticholinergic drug, suchas atropine or homatropine, usually brings relief fromthe pain and systemic effects (including the nauseaand vomiting), but because these drugs cause blurringof vision, they should not be used unless the pain issevere. 62The NoseRhinorrhea is common after both local and systemicnerve agent exposure. It may occur soon after exposureto a small amount of vapor and sometimes precedesmiosis and dim vision, or it may occur in the absenceof miosis. Even a relatively small exposure to vapor172