3
4 0 2 Case reports Discussion Hydrofluoric acid is commonly used i n indus- t r y a s a cleaning agent f o r metals a n d glass.' Burns resulting from contact with i t m a y present early or late to t h e A & E department. Early presentation, with severe pain, occurs with concentrations of greater than 20%.2 Burns resulting from more dilute forms o f t h e acid may present with delayed onset of pain, erythema, an d crust formation a t t h e site of t h e burn. O n e o f th e characteristic features of hydrofluoric acid burns i s intense a n d often delayed pain. This may occur despite standard first a id treatment. T h e pathophysiology is said t o b the permeability o f t h e fluoride ion, which enables i t to rapidly penetrate skin, sub- cutaneous tissues, a n d bone. Rapid binding of calcium b y t h e fluoride i o n forms insoluble salts, t h e ensuing drop in local tissue calcium interferes with cellular function a n d causes cell death. Cell death i n turn releases large amounts of potassium, which irritates nerve endings, causing severe pain. Methods of treating these burns are aimed a t local pain control a n d prevention of progres- sive tissue damage. T h e most effective o f these h a s repeatedly been shown t o b e t h e local infil- tration o f calcium gluconate o r application o f topical calcium carbonate t o bind t h e fluoride ion, forming a n insoluble salt.'3 This removal o f t h e free fluoride i o n prevents progressive tis- s ue necrosis a n d achieves simultaneous pain control. More recently, the identification o f severe hypocalcaemia associated with fluoride loading h a s raised concerns over t h e life threat- ening, rather than limb threatening, nature o f this injury." Topical a n d local infiltration using g e l o r local injection are, however, n o t without prob- lems. G e l ma y be ineffective, particularly i n delayed presentations. Local infiltration is often found to be t o exceedingly painful, an d h a s t h e added disadvantage of potential compromise t o t h e local circulation, possibly requiring concomitant fasciotomies when treating digital burns.2 T h e us e o f local anaes- thetic infiltration i s contraindicated, a s the ces- sation o f pain i s used as a n indicator of effective treatment.' Intra-arterial infusion h a s been advocated, bu t is technically more demanding an d potentially more hazardous. Regional intravenous calcium injection using a Bier's block technique satisfies a l l the aims o f effective treatment of hydrofluoric acid burns. T h e 1 5 ml o f 1 0 % calcium gluconate, i f released suddenly, ca n cause flushing, headache, a n d arrhythmia, s o we recommend the u s e of a dou- b le cuff tourniquet an d cardiac monitoring during t h e procedure. Despite these potential problems w e feel that this amount ofcalcium is safe, given that there i s rapid binding to fluoride. Furthermore, t h e risks must b e balanced against t h e hazards of continued tissue destruction a n d t h e need f o r adequate pain relief. Both these patients received rapid a n d complete analgesia, tissue necrosis w a s halted, a n d possible systemic effects from either t h e burn o r its treatment were avoided. This procedure i s technically much sim- pler an d seemingly safer than intra-arterial infusion. I t i s easy t o perform i n a n A& E depart- ment when t he patient first presents. Doctors working i n A &E departments should be aware of this procedure, which c a n b e used effectively t o treat hydrofluoric acid burns t o both upper a n d lower limbs. 1 Chick LR , Borah G . Calcium carbonate ge l therapy f o r hydrofluoric acid burns of t h e hand. Plastic Reconstr Surg 1990;86:935-9. 2 Anderson WJ,Anderson JR . Hydrofluoric acid burns of t h e hand: mechanism o f injury a n d treatment. J Hand Surg 1988; 13A:52-7. 3 Blunt C P. Treatment of hydrofluoric acid burns with injec- tion with calcium gluconate. Indust M e d Surg 1964;33: 869-71. 4 Kohnlein HE, Achinger R . A n e w method of treatment of hydrofluoric acid burns o f t h e extremities. Chir Maxillofac Plast 1982;6:297-305. 5 Sheridan R L , Ryan C M, Quinby WC , Blair J , Tomkins R G , Burke J F . Emergency management of major hydrofluoric acid burns. Burns 1995;21:62-4. Stun gun injury Peter Burdett-Smith Accident a n d Emergency, T h e Royal Liverpool University Hospitals, Liverpool, UK P Burdett-Smith Correspondence t o : M r P Burdett-Smith, Consultant in A& E Medicine, T h e Royal Liverpool University Hospitals, Prescot Street, Liverpool L 7 8XP. Accepted f o r publication 1 3 June 1997 Abstract A case i s presented o f injury b y a "stun gun." T h e different types o f electric shock devices produced commercially ar e sum- marised a n d t h e potential injuries dis- cussed. (7 Accid Emerg M e d 1997;14:402-404) Keywords: stun gun; electrical burn Case report A 5 8 year old m a n attended t h e accident a n d emergency (A&E) department after being attacked with what h e described a s a "cattle prod" during a robbery. H e described sparks being emitted from the device, which was deliberately applied t o t h e dorsum o f h i s right hand a s h e tried t o defend himself. Examin- ation revealed a partial thickness electrical burn to the hand, with extensive soft tissue swelling. T h e wound w a s dressed a n d he was reviewed in t h e clinic. Figure 1 , taken 10 days after t h e assault, shows the haematoma secondary t o t h e deep soft tissue injury. Just visible a r e the contact points o f th e electrodes o n th e skin. T h e haematoma w a s aspirated an d t h e injury resolved i n four weeks.

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4 0 2 C a s e r e p o r t s

D i s c u s s i o nH y d r o f l u o r i c a c i d i s c ommon l y u s e d i n i n d u s -t r y a s a c l e a n i n g a g e n t f o rm e t a l s a n d g l a s s . 'B u r n s r e s u l t i n gf r o m c o n t a c t w i t h i t mayp r e s e n t e a r l yo r l a t e t ot h e A&E d e p a r t m e n t .E a r l y p r e s e n t a t i o n , w i t h s e v e r e p a i n ,o c c u r sw i t h c on ce n t ra t i on s o f g r e a t e r t h a n 2 0 % . 2B u r n s r e s u l t i n gf r o m more d i l u t ef o r m s o f t h ea c i d may p r e s e n t w i t h d e l a y e d o n s e t o f p a i n ,e r y t h e m a ,a n d c r u s t f o r m a t i o n a t t h e s i t eo f t h eb u r n . One o f t h e c h a r a c t e r i s t i cf e a t u r e so fh y d r o f l u o r i c a c i d b u r n s i s i n t e n s e a n d o f t e nd e l a y e dp a i n .T h i s may o c c u r d e s p i t es t a n d a r df i r s ta i dt r e a t m e n t . The p a t h o p h y s i o l o g yi s s a i dt o b e t h e p e r m e a b i l i t y o f t h e f l u o r i d ei o n ,w h i c he n a b l e s i t t o r a p i d l yp e n e t r a t e s k i n ,s u b -c u t a n e o u s t i s s u e s ,a n d b o n e . R a p i d b i n d i n g o fc a l c i u m b y t h e f l u o r i d ei o n f o r m s i n s o l u b l es a l t s , a n d t h e e n s u i n g d r o p i n l o c a l t i s s u ec a l c i u m i n t e r f e r e sw i t h c e l l u l a rf u n c t i o n a n dc a u s e s c e l ld e a t h . C e l l d e a t h i n t u r n r e l e a s e sl a r g ea m o u n t s o f p o t a s s i um , w h i c h i r r i t a t e sn e r v e e n d i n g s ,c a u s i n g s e v e r e p a i n .

M e t h o d so f t r e a t i n gt h e s e b u r n s a r e a i m e da tl o c a lp a i n c o n t r o l a n d p r e v e n t i o n o f p r o g r e s -s i v e t i s s u ed a m a g e .The m o s t e f f e c t i v eo f t h e s eh a s r e p e a t e d l yb e e n s h o w nt o b e t h e l o c a li n f i l -t r a t i o no f c a l c i u m g l u c o n a t e o r a p p l i c a t i o no ft o p i c a lc a l c i u m c a r b o n a t e t o b i n d t h e f l u o r i d ei o n ,f o r m i n g a n i n s o l u b l e s a l t . ' 3T h i s r e m o v a lo f t h e f r e ef l u o r i d ei o n p r e v e n t s p r o g r e s s i v et i s -s u e n e c r o s i s a n d a c h i e v e s s i m u l t a n e o u s p a i nc o n t r o l .More r e c e n t l y ,t h e i d e n t i f i c a t i o no fs e v e r e h y p o c a l c a e m i aa s s o c i a t e d w i t h f l u o r i d el o a d i n g h a s r a i s e d c o n c e r n s o v e r t h e l i f et h r e a t -e n i n g ,r a t h e r t h a n l i m b t h r e a t e n i n g ,n a t u r e o ft h i si n j u r y . "

To p i c a l a n d l o c a li n f i l t r a t i o nu s i n g g e l o rl o c a li n j e c t i o na r e ,h o w e v e r ,n o t w i t h o u t p r o b -l e m s . G e l may b e i n e f f e c t i v e ,p a r t i c u l a r l yi nd e l a y e d p r e s e n t a t i o n s .L o c a l i n f i l t r a t i o ni so f t e n f o u n d t o b e t o e x c e e d i n g l yp a i n f u l ,a n dh a s t h e a d d e d d i s a d v a n t a g e o f p o t e n t i a l

c o m p r o m i s et o t h e l o c a lc i r c u l a t i o n ,p o s s i b l yr e q u i r i n g c o n c o m i t a n t f a s c i o t om i e s whent r e a t i n gd i g i t a lb u r n s . 2 The u s e o f l o c a la n a e s -t h e t i ci n f i l t r a t i o ni s c o n t r a i n d i c a t e d ,a s t h e c e s -s a t i o no f p a i n i su s e d a s a n i n d i c a t o ro f e f f e c t i v et r e a t m e n t . 'I n t r a - a r t e r i a li n f u s i o n h a s b e e na d v o c a t e d , b u t i s t e c h n i c a l l ym o r e d e m a n d i n ga n d p o t e n t i a l l ymore h a z a r d o u s .

R e g i o n a li n t r a v e n o u sc a l c i u mi n j e c t i o nu s i n g aB i e r ' sb l o c k t e c h n i q u e s a t i s f i e sa l l t h e a i m s o fe f f e c t i v et r e a t m e n t o f h y d r o f l u o r i ca c i db u r n s .T h e 1 5 m l o f 10% c a l c i u mg l u c o n a t e ,i fr e l e a s e ds u d d e n l y ,c a n c a u s e f l u s h i n g ,h e a d a c h e , a n da r r h y t hm i a ,s owe r e commend t h eu s e o f a d o u -b l e c u f f t o u r n i q u e t a n d c a r d i a cmo n i t o r i n gd u r i n g t h e p r o c e d u r e .D e s p i t e t h e s ep o t e n t i a lp r o b l e m swe f e e lt h a tt h i sa m o u n to f c a lc iu m i ss a f e ,g i v e nt h a tt h e r ei s r a p i db i n d i n g t o f l uo r i d e .F u r t h e r m o r e ,t h er i s k sm u s tb e b a l a n c e da g a i n s tt h eh a z a r d s o f c o n t i n ue d t i s s u ed e s t r u c t i o na n dt h e n e e d f o r a d e q u a t e p a i n r e l i e f .B o t h t h e s ep a t i e n t sr e c e i v e dr a p i da n d c o m p l e t e a n a l g e s i a ,t i s s u en e c r o s i sw a s h a l t e d ,a n d p o s s i b l es y s t e m i ce f f e c t sf r o m e i t h e rt h eb u r n o r i t st r e a t m e n t w e r ea v o i d e d .T h i s p r o c e d u r ei s t e c h n i c a l l ymuch s i m -p l e r a n d s e em i n g l y s a f e r t h a n i n t r a - a r t e r i a li n f u s i o n .I t i s e a s y t o p e r f o r mi n a n A&E d e p a r t -m e n t when t h e p a t i e n tf i r s tp r e s e n t s .D o c t o r sw o r k i n gi nA&E d e p a r t m e n t ss h o u l db e a w a r e o ft h i sp r o c e d u r e ,w h i c h c a n b e u s e d e f f e c t i v e l yt ot r e a th y d r o f l u o r i c a c i db u r n s t o b o t h u p p e r a n dl o w e rl i m b s .

1 C h i c k L R , B o r a h G . C a l c i u m c a r b o n a t e g e l t h e r a p y f o rh y d r o f l u o r i ca c i db u r n s o f t h e h a n d . P l a s t i cR e c o n s t r S u r g1 9 9 0 ; 8 6 : 9 3 5 - 9 .

2 A n d e r s o nW J , A nd e r so nJ R .Hy d r o f l u o r i ca c i db u r n s o f t h eh a n d : m e c h a n i s mo f i n j u r ya n d t r e a t m e n t . J Hand S u r g1 9 8 8 ;1 3 A : 5 2 - 7 .

3 B l u n t C P . T r e a t m e n to f h y d r o f l u o r i c a c i db u r n s w i t h i n j e c -t i o nw i t h c a l c i u m g l u c o n a t e .I n d u s t Me d S u r g 1 9 6 4 ; 3 3 :8 6 9 - 7 1 .

4 K o h n l e i nHE, A c h i n g e rR . A n ew m e t h o do f t r e a t m e n t o fh y d r o f l u o r i ca c i d b u r n s o f t h ee x t r e m i t i e s .C h i r Ma x i l l o f a cP l a s t1 9 8 2 ; 6 : 2 9 7 - 3 0 5 .

5 S h e r i d a nR L , R y a nCM, Q u i n b yWC , B l a i rJ ,T o m k i n sR G ,B u r k e J F .E m e r g e n c ymanagemen t o f m a j o r h y d r o f l u o r i ca c i d b u r n s . B u r n s 1 9 9 5 ; 2 1 : 6 2 - 4 .

S t u n gun i n j u r y

P e t e r B u r d e t t - S m i t h

A c c i d e n t an dEmergency, Th e R o y a lL i v e r p o o lU n i v e r s i t yH o s p i t a l s , L i v e r p o o l ,UKP B u r d e t t - S m i t h

C o r r e s p o n d e n c et o :Mr P B u r d e t t - Sm i t h ,C o n s u l t a n ti nA&EM e d i c i n e ,The R o y a lL i v e r p o o l U n i v e r s i t yHo s p i t a l s , P r e s c o t S t r e e t ,L i v e r p o o lL7 8 X P.

A c c e p t e df o rp u b l i c a t i o n1 3 J u n e 1 9 9 7

A b s t r a c tA c a s e i s p r e s e n t e d o f i n j u r y by a " s t u ng u n . " T h e d i f f e r e n t t y p e s o f e l e c t r i c shockd e v i c e s p r o du c e d commerc ia l ly a r e s um -mar i s ed and t h e p o t e n t i a l i n j u r i e s d i s -c u s s e d .( 7Ac c i dE m e r gMed 1 9 9 7 ; 1 4 : 4 0 2 - 4 0 4 )

K e y w o r d s :s t u n g u n ; e l e c t r i c a lb u r n

Case r e p o r tA 5 8 y ea r o l d m an a t t e n d e d t h e a c c i d e n t a n de m e r g e n c y ( A & E ) d e p a r t m e n t a f t e r b e i n ga t t a c k e d w i t h w h a t h e d e s c r i b e d a s a " c a t t l e

p r o d " d u r i n g a r o b b e r y . He d e s c r i b e d s p a r k sb e i n g e m i t t e d f r o m t h e d e v i c e ,w h i c h w a sd e l i b e r a t e l ya p p l i e d t o t h e do r sum o f h i sr i g h th a n d a s h e t r i e dt o d e f e n d h i m s e l f .E x a m i n -a t i o n r e v e a l e d a p a r t i a lt h i c k n e s s e l e c t r i c a lb u r n t o t h e h a n d , w i t h e x t e n s i v e s o f t t i s s u es w e l l i n g .The wound w a s d r e s s e d a n d h e w a sr e v i e w e di n t h e c l i n i c .

F i g u r e 1 , t a k e n 1 0 d a y s a f t e rt h e a s s a u l t ,s h o w s t h e haematoma s e c o n d a r y t o t h e d e e ps o f t t i s s u ei n j u r y .

J u s tv i s i b l ea r e t h e c o n t a c t

p o i n t s o f t h e e l e c t r o d e son t h e s k i n .Th ehaematoma w a s a s p i r a t e d a n d t h e i n j u r yr e s o l v e d i n f o ur w e e k s .

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C a s e r e p o r t s

D i s c u s s i o nT h e r e a r et h r e e m a i n t y p e s o f d e v i c e d e s i g n e dt o ( d e l i b e r a t e l y )i mp a r t a ne l e c t r i cs h o c k : s t u ng u n s , s h o c k b a t o n s , a n d c a t t l ep r o d s . 'Theys h a r e t h e s a m eb a s i c d e s i g nb u t d i f f e ri n e n e r g yo u t p u t a n d p o t e n t i a lf o ri n j u r y .

STUN GUN

D e v e l o p e di n A m e r i c ai n 1 9 7 9 , s t u n g u n s a r eh a n d h e l d ,b a t t e r y o p e r a t e d d e v i c e s ,w i t h av a r i e t yo f n a m e s s u c h a s " C o s m i cD e f e n d e r "a n d " L i g h t n i n g S t r i k e . "S im i l a r i n d e s i g n t oc a t t l ep r o d s , w i t h t w o e l e c t r o d e s a p p r o x i m a t e l y5 c m a p a r t ,t h e y a r e d e s i g n e d t o b e p r e s s e da g a i n s tt h e v i c t i m ' ss k i na n d a n e l e c t r i cs h o c ki sa d m i n i s t e r e d when t h e s wi t c h i s p r e s s e d .Av a r i e t yo f w a r n i n g d e v i c e s a r e i n c o r p o r a t e di n t o some m o d e l s , i n c l u d i n g t w o f u r t h e re l e c t r o d e s p l a c e d a p p r o x i m a t e l y2 c m a p a r ta n d f a c i n g t o g e t h e r ,w h i c h p r o d u c e v i s i b l ea r c i n g ,a n d l i g h t so r a u d i b l ew a r n i n g st ow o u l db e a s s a i l a n t s .I n some m o d e l s , t h e e l e c -t r o d e s a r e s h a r p a n d d e s i g n e dt o p e ne t ra t e t h es k i n .

A d e v e l o p m e n to f t h i s p r i n c i p l ei s t h e" Ta s e r " ( T h o m a sA S w i f t ' se l e c t r i cr i f l e ) ,u s e di n t h e USA b y p o l i c eo f f i c e r s . 2T h i s r e s e m b l e sal a r g e t o r c h ,b u t b e n e a t h t h e l i g h ts o u r c e a r eh o u s e d c a s s e t t e sc o n t a i n i n g t w o d a r t s w i t hb a r b e d h o o k s a t o n e e n d a n d a s p o o l o f f i n ew i r e c o n n e c t i n g t h e m t o t h e d ev ic e p r o p e r .Whe n t h e t r i g g e ri s p r e s s e d , t he d ar ts a r e f i r e du p t o a d i s t a n c e o f 1 5 f e e t ,a n d a r ed e s i g n e dt oembed i n c l o t h i n go r t h e s k i n .P r e s s i n g t h et r i g g e ra c t i v a t e st h e c u r r e n t ,c a u s i n g t e t a n y o ft h e mu s c l e s , u s u a l l y c a u s i n g t h e v i c t i m t o f a l l .The c u r r e n t i s e f f e c t i v et h r o u g h u p t o 5 cm o fc l o t h i n g .A f t e r t h e v i c ti m h a s b e e n r e s t r a i n e d ,

F i g u r e 1 Haema t oma s e c o n d a r yt o t h ed e e p s o f tt i s s u ei n j u r y .J u s t v i s i b l ear e t h ec o n t a c t p o i n t so f t h ee l e c t r o d e son

t h e s k i n .

t h e w i r e s h a v e t o b e c u t ,a n d t h e p a t i e n tt a k e nt o h o s p i t a l f o rt h e d a r t st o b e r e m o v e du n d e rl o c a la n a e s t h e s i a .I n N o r t h A m e r i c at h e y a r ec o n s i d e r e d u s e f u lw e a p o n s f o r d e a l i n g w i t hp e o p l e d e r a n g e d b y t h e e f f e c t so f d r u g s ,e s p e c i a l l yPCP ( p h e n c y c l i d i n e ) , a s t h e a l t e r n a -t i v emethod o f s u b d u i n gi s t h e . 3 8 s p e c i a lw i t ha 50% m o r t a l i t y !I t i s a l s op o s s i b l et o r e m o v e

t h e c a s s e t t e sf r o m t h e Ta s e r a n d i n s e r te x t e n d -i b l e 1 2 i n c h e l e c t r o d e s ,a l l o w i n g t h e i n s t r u -men t t o b e u s e da s a s t u n g u n .

ELECTRIC SHOCK BATON

T h i s i m p l e m e n tl o o k s l i k ea p o l i c eb a t o n b u tw i t h t w o s t u d e l e c t r o d e s a t o n e e n d . T h e s e a r ed e s i g n e d t o b e p r e s s e d a g a i n s tt h e s k i n .Thei n s t r u m e n t i s n o t d e s i g n e dt o i n c a p a c i t a t e ,b u tt o e n c o u r a g et h e v i c t i m t o m o v e !A v a r i a n t o ft h i s d e s i g n i s t h e e l e c t r i c" w a n d "w h i c h h a sw i r e s w r a p p e da r o u n d t h e l e n g t h ,a n d somem o d e l si n c o r p o r a t e b o t h .

CATTLE PROD

Co r r e c t l y t e r m e d a n i m a l " c o a x e r s " ,t h e s ed e v i c e s h a v e t h e same b a s i cd e s i g n a s t h e s t u ng u n b u t t h e a u d i b l e a n d v i s u a lw a r n i n g sa r e o fc o u r s e u n n e c e s s a r y .T h e r e i s a h u g ev a r i e t yo fd e s i g n ( f i g2 ) a n d s e e m i n g l yno r e s t r i c t i o nont h e i rs a l e .A s w e l l a s " c o a x i n g , "i mm o b i l i s a t i o na n d e v e n a n a e s t h e s i a o f c a t t l eb y e l e c t r i c a lmeans i s p r a c t i s e di n s ome c o u n t r i e s ,b u t n o tt h e U n i t e d K i n g d o m .T h e s e l a t t e rd e v i c e s a r en e c e s s a r i l yl a r g ea n d u n l i k e l yt o b e u s e d a sw e a p o n sa g a i n s th u m a n s .

PHYSICS

S t u n g u n s , i n c l u d i n g t h e Ta s e r ,p r o d u c ea p e a kv o l t a g eo f u p t o 5 0 0 0 0 v o l t swhen d i s c h a r g e d ,i n a s e r i e so f s h o r t d u r a t i o n , h i g h p e a k p u l s e s ,b e t w e e n1 0 a n d 1 5 p e r s e c o n d . 3 T h i s d e l i v e r sa p p r o x i m a t e l y0 . 8 j o u l e so f e n e r g y .The b a t o n sa n d c o a x e r s d e l i v e ra r e g u l a ra l t e r n a t i n gc u r r e n t , w i t h p e a kv o l t a g e sv e r y much l o w e ra ta r o u n d 2 00v o l t s . 'T h e e f f e c t so f t h es e c ur re n t s on t h e v i c t i m

d e p e n d s on t h e r e s i s t a n c eo f t h e s k i n ,w h i c hd e p e n d s i n t u r n on p r e s s u r e o f c on t a c t ,w h e t h e r t h e s k i n i s i n t a c t ,a n d i f i t i s w e t . I ta p p e a r s t h a tt h e e l e c t r i c a li m p u l s e i s n o t j u s tl o c a l i s e dt o b e t w e e nt h e e l e c t r o d e s ,b u t s p r e a d sf r o m t h e p o i n t o f c o n t a c t a l o n g c h a n n e l s o f l o wr e s i s t a n c e ,t h a t i s , n e u r o v a s c u l a r b u n d l e s ,t h r o u g h o u t t h e b o d y . Thus a d i s c h a r g eo fh a l f a s e c o n d w i l l r e p e lt h e v i c t i m ,b u t ad i s c h a r g e o f o n e t o t w o s e c o n d s w i l l c a u s et e t a n y o f most o f t h e s k e l e t a lm u s c l e a n d t h ev i c t i m w i l lf a l l .A d i s c h a r g eo f t h r e e t o f i v es e c -o n d s w i l ll e a v et h e v i c t i m u n a b l e t o f u n c t i o nf o ru p t o 1 5 m i n u t e s . S t i f f n e s sa n d p a i n i n t h em u s c l e sa t t h e s i t ea r e c o mm o n a f t e rp a r a l y s i sh a s worn o f f . '

C o n c e r nh a s b e e n e x p r e s s e da s t o t h e p o t e n -

t i a l f o r t he se d ev i c es t o i n d u c e v e n t r i c u l a rf i b r i l l a t i o n .The h e a r t may b e f i b r i l l a t e db y t h ep a s s a g eo f a s l i t t l ea s 0 . 1A a p p l i e d f o r0 . 5 s e c -o n d s . 4H o w e v e r ,a l a r g e rc u r r e n t n e e d s t o b e

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F i g u r e2 A n i m a lc o a x e r s . P h o t o g r a p h sk i n d l yp r o v i d e db yK r u u s eUK L t d ,v e t e r i n a r ys u p p l i e r s .

a p p l i e d t o t h e b o d ya s a w h o l ef o rt h e p e r c e n t -a g e p a s s i n g a c r o s s t h e m y o c a r d i u mt o r e a c ht h i sl e v e l .The e n e r g y d e l i v e r e dt o t h e b o d yb yo n e s h o c k f r o m a s t u n gun i s b e l o wt h e t h re s h-o l d f o ri n d u c i n g v e n t r i c u l a rf i b r i l l a t i o n . 'How-e v e r ,t h e e f f e c to f r e p e a t e d s h o c k s o r a p p l i c a -t i o no f t h e weapon d i r e c t l yo v e r t he h e a r t i s n o tk n o w n . S u d d e n d e a t h s h a v e b e e n r e p o r t e dw i t h Ta s e r u s e , b u t a l t h o u g h t h e s e w e r et h o u g h t t o b e c a r d i a c i n o r i g i n ,d r u g i n t o x i c a -t i o nw a s f e l t t o b e t h e p r e c i p i t a t i n gc a u s e . 2I na d d i t i o n ,t h e r e i s a r i s kt h a ta p e r s o n i n c o n t a c tw i t h t h e v i c t i m w i l la l s or e c e i v ea n i n c a p a c i t a t -i n g s h o c k .

I n c o n t r a s t ,t h e d i s c h a r g ef r o m c a t t l ec o a x e r sa n d s h o c kb a t o n s i s l i m i t e d t o t h e a r e a b e t w e e nt h e e l e c t r o d e s .T h e s e d e v i c e s t he re fo re c a u sep a i n a t t h e s i t e ,w i t h p o s s i b l y some v e r y l o c a l -i s e dm u s c l e s p a s m .

SUMMARY

F r om t h i s p a t i e n t s 'd e s c r i p t i o n ,i t i s l i k e l yh a t t h e weapon w a s n o t a v e t e r i n a r yi m p l e -m e n t , b u t a " s t u n g u n . " He w a s n o t i n c a p a c i -t a t e d b y t he d ev ic e a s c o n t a c t w a s b r i e f ,a n dt h e e f f e c t sw e r e l i m i t e dt o a l o c a l i s e de l e c t r i c a lb u r n .

I n t h e U n i t e d K i n g d o m , s t u n g u n s a r eb a n n e db y t h e 1 9 6 8 F i r ea rm sAc t , a s t h e y a r ec a p a b l e o f d i s c h a r g i n g a " n o x i o u s t h i n g , "t h a ti s , e l e c t r i c i t y . 'H o w e v e r ,t h e y w e r e a v a i l a b l et h r o u g h m a i l o r d e r u n t i la t e s t c a s e i n 1 9 8 8w h i c hc o n f i r m e dt h e i rc l a s s i f i c a t i o na s p r o h i b -i t e dw e a p o n s .Mos t a r e m a n u f a c t u r e di n t h eF a r E a s t a n d a r e w i d e l y a v a i l a b l e i nmanyc o u n t r i e s f o r l a w e n f o r c e m e n t o r p e r s o n a l

d e f e n c e .T h e s ew e a p o n sa r e e a s i l yc o n c e a l e d a n d a r e

v e r y e f f e c t i v e .F o r t u n a t e l y t h e y a r e n o t com-m o n l yu s e d i n t h i sc o u n t r y b u t c a n i n f l ic t s e r i -o u s i n j u r y .A l t h o u g h no c a s e s h a v e b e e nr e p o r t e d ,t h e p o t e n t i a le x i s t sf o r v e n t r i c u l a rf i b r i l l a t i o nt o b e i nd u c edb y r e p e a t e d s h o c k s .

1 R o b i n s o nMN, B r o o k s CG , R e n s h a wGD. E l e c t r i cs h o c kd e v i c e s a n d t h e i r e f f ec t so n t h e human b o d y .Me d S c iLaw19 9 0 ; 3 0 : 2 8 5 - 3 0 0 .

2 O r d o gG J ,Wa s s e r b e r g e r J ,S c h l a t e rT ,B a l a s u b r a m a n i umS .E l e c -t r o n i cg u n ( Ta s e r )i n j u r i e s .Ann E m e r gMe d 1 9 8 7 ; 1 6 : 7 3 - 8 .

3 F i s h R . E l e c t r i cs h oc k . P a r tI I I .D e l i b e r a t e l ya p p l i e de l e c t r i cs h o c k s a n d t h e t r e a tm e n to f e l e c t r i ci n j ur i es . JE m e r gMe d1 9 9 3 ; 11 : 5 9 9 - 6 0 3 .

4 S i m p s o nK , K n i g h t B . F o r en s i c m e d i c in e .L o n d o n :E d w a r dA r n o l d , 1 9 8 5 .