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10. Medical and minor surgical procedures
Venomous bites and stings
Snake bites and envenomation
– M o re than 5 0 % o f the bites are d ry bites, i.e. no enveno m atio n o ccurred . In the event
th at veno m is injected , the severity o f enveno m atio n d ep end s o n th e sp ecies, the
am o unt o f veno m injected , the lo catio n o f the bite (bites o n the head and neck are the
m o st d angero us) and the weight, general co nd itio n and age o f the ind ivid ual (m o re
serio us in child ren).
– It is rare that the snak e invo lved is id entified . H o wever, o bservatio n o f the clinical
signs m ay o rient d iagno sis and m anagem ent. T wo m ajo r sy nd ro m es are id entified :
• neuro lo gical d iso rd ers that evo lve to ward s resp irato ry m uscle p araly sis and co m a
are co m m o n m anifestatio ns o f elap id enveno m atio n (co bra, m am ba, etc.);
• extensive lo cal lesio ns (intense p ain, inflam m atio n with o ed em a and necro sis) and
co agulatio n abno rm alities are co m m o n m anifestatio ns o f vip erid o r cro talid (rattle
snak e) enveno m atio n.
C linical m anifestatio ns and m anagem ent o f bites and enveno m atio ns are d escribed in
the fo llo wing p age.
– E arly d iagno sis and m o nito ring o f co agulatio n abno rm alities is based o n who le blo o d
clo tting tests p erfo rm ed in a d ry tube (at the p atient‟s arrival and then every 4 to
6 ho urs fo r the first d ay ).
T ak e 2 to 5 m l o f who le blo o d , wait 3 0 m inutes and exam ine the tube:
• C o m p lete clo tting: no co agulatio n abno rm ality
• I nco m p lete clo tting o r no clo tting: co agulatio n abno rm ality , suscep tibility to
bleed ing1
I n th e event o f co agulatio n abno rm alities, co ntinue to m o nito r o nce d aily until
co agulatio n returns to no rm al.
– A etio lo gical treatm ent is based o n th e ad m inistratio n o f snak e antiveno m serum ,
o nly if there are clear clinical manifestations of envenomation o r coagulation abnormalities
are o bserved . A ntiveno m sera are effective, but rarely available ( verify lo cal
availability ) and d ifficult to sto re.
A ntiveno m serum sho uld be ad m inistered as early as p o ssible: by I V infusio n ( in
0 .9 % so d ium chlo rid e) if using a p o o rly p urified serum ; by slo w IV in the event o f10
severe enveno m atio n if the serum is k no wn to be well p urified . Rep eat antiveno m
serum ad m inistratio n after 4 o r 6 ho urs if the sy m p to m s o f enveno m atio n p ersist.
F o r all p atients, be p rep ared fo r an anap h y lactic reactio n, wh ich , d esp ite its
p o tential severity (sho ck ), is usually m o re easily co ntro lled than co agulatio n
d iso rd ers o r serio us neuro lo gical d iso rd ers.
– I n asy m p to m atic p atients ( bites witho ut signs o f enveno m atio n and with no rm al
co agulatio n), m o nito ring m ust co ntinue fo r at least 1 2 ho urs (2 4 ho urs p referred ).
1 There can be a considerable delay between the decrease in coagulation factors (less than 30 minutes after t
bite) and the first signs of bleeding (other than bleeding at the site of the bite and/or the development of sero-
sanguinous blisters), which may appear only 3 days after the bite. Conversely, bleeding may resolve prior to
normalization of coagulation parameters.
283
Venomous bites and stings
Snake bites and envenomation
– M o re than 5 0 % o f the bites are d ry bites, i.e. no enveno m atio n o ccurred . In the event
th at veno m is injected , the severity o f enveno m atio n d ep end s o n th e sp ecies, the
am o unt o f veno m injected , the lo catio n o f the bite (bites o n the head and neck are the
m o st d angero us) and the weight, general co nd itio n and age o f the ind ivid ual (m o re
serio us in child ren).
– It is rare that the snak e invo lved is id entified . H o wever, o bservatio n o f the clinical
signs m ay o rient d iagno sis and m anagem ent. T wo m ajo r sy nd ro m es are id entified :
• neuro lo gical d iso rd ers that evo lve to ward s resp irato ry m uscle p araly sis and co m a
are co m m o n m anifestatio ns o f elap id enveno m atio n (co bra, m am ba, etc.);
• extensive lo cal lesio ns (intense p ain, inflam m atio n with o ed em a and necro sis) and
co agulatio n abno rm alities are co m m o n m anifestatio ns o f vip erid o r cro talid (rattle
snak e) enveno m atio n.
C linical m anifestatio ns and m anagem ent o f bites and enveno m atio ns are d escribed in
the fo llo wing p age.
– E arly d iagno sis and m o nito ring o f co agulatio n abno rm alities is based o n who le blo o d
clo tting tests p erfo rm ed in a d ry tube (at the p atient‟s arrival and then every 4 to
6 ho urs fo r the first d ay ).
T ak e 2 to 5 m l o f who le blo o d , wait 3 0 m inutes and exam ine the tube:
• C o m p lete clo tting: no co agulatio n abno rm ality
• I nco m p lete clo tting o r no clo tting: co agulatio n abno rm ality , suscep tibility to
bleed ing1
I n th e event o f co agulatio n abno rm alities, co ntinue to m o nito r o nce d aily until
co agulatio n returns to no rm al.
– A etio lo gical treatm ent is based o n th e ad m inistratio n o f snak e antiveno m serum ,
o nly if there are clear clinical manifestations of envenomation o r coagulation abnormalities
are o bserved . A ntiveno m sera are effective, but rarely available ( verify lo cal
availability ) and d ifficult to sto re.
A ntiveno m serum sho uld be ad m inistered as early as p o ssible: by I V infusio n ( in
0 .9 % so d ium chlo rid e) if using a p o o rly p urified serum ; by slo w IV in the event o f10
severe enveno m atio n if the serum is k no wn to be well p urified . Rep eat antiveno m
serum ad m inistratio n after 4 o r 6 ho urs if the sy m p to m s o f enveno m atio n p ersist.
F o r all p atients, be p rep ared fo r an anap h y lactic reactio n, wh ich , d esp ite its
p o tential severity (sho ck ), is usually m o re easily co ntro lled than co agulatio n
d iso rd ers o r serio us neuro lo gical d iso rd ers.
– I n asy m p to m atic p atients ( bites witho ut signs o f enveno m atio n and with no rm al
co agulatio n), m o nito ring m ust co ntinue fo r at least 1 2 ho urs (2 4 ho urs p referred ).
1 There can be a considerable delay between the decrease in coagulation factors (less than 30 minutes after t
bite) and the first signs of bleeding (other than bleeding at the site of the bite and/or the development of sero-
sanguinous blisters), which may appear only 3 days after the bite. Conversely, bleeding may resolve prior to
normalization of coagulation parameters.
283
