Envenomation Flashcards
- Name 3 syndromic snake bite groups ?
- Painful progressive swelling
(PPS) - Progressive weakness (PW)
- Bleeding (B)
Name examples of snakes in each group ?
Management of venom ophthalmia?
Painful progressive swelling (PPS)* Pathophysiology ? what toxin ?
What clinical presentation ?
Cytotoxic venom
Swelling
commences around the bite site within a few
minutes and spreads mainly in a proximal
direction. It is painful, often tender, warm to
hot and indurated. The duration and rate at
which it spreads is mainly snake species
dependent. It is quicker with the adders at 5
– 10 cm or more per hour whilst that due to
stiletto snake and spitting cobra bites
spreads at about 1 - 2 cm per hour. It spreads
faster soon after the bite and slows before
stopping. Within 1 – 2 hours of the bite there
is usually painful regional lymphadenopathy
Complications of PPS? 3 groups local , regional systemic
Local, such as bite site blister,
haematoma or necrosis (10%).
* Regional, such as compartment syndrome,
nerve and vessel entrapment
and deep vein thrombosis
(uncommon).
* Systemic, due to loss of fluid and
blood components into the swollen
area which may lead to hypotension,
anaemia, hypoalbuminaemia and
hypofibrinogenaemia with prolongation
of the PTT and INR. This
occurs mostly in those cases
where swelling rapidly spreads to
the trunk and is most common
following puff adder bites. Cardiotoxicity
and pulmonary oedema due
to circulating venom have only been
described following Gaboon adder
bites.
Management?
?
Type of antivenom ?
Indications for antivenom in pps ?
Progressive weakness (PW) toxin and clinical presentation ?
Neurotoxin
Injected neurotoxic venom produces
striated muscle dysfunction:
* Venom of the non-spitting cobras
(Cape (Naja nivea), snouted (N.
annulifera), forest (N. melanoleuca)
and Anchieta’s (N. anchietae)) contain
curare-like post-synaptic toxins.
* Mamba (Dendroaspis spp.) bites
lead to excessive circulating levels
of acetylcholine
* Some of the small adders, i.e. berg
adder (Bitis atropos), Peringuey’s
adder (B. peringueyi), desert
mountain adder (B. xeropaga)
contain pre-synaptic toxins
PW- Management?
Type of antivenom ?
Indications for anitivenom ?
Polyvalent
Name snake in mixed group?
Rinkhals
Bleeding group - presentation ?
Injected haemotoxic venom may lead
to a bleeding diathysis. Boomslang
(Dispholidus typus) and vine snake
(Thelotornis spp.) venom contains
procoagulant toxins which activate
factors II and X leading to a consumption
coagulopathy with all the possible
attendant complications and mortality.19,20
These bites are uncommon.
Puff adder bites are far more
common and these snakes are
responsible for the majority of patients
with bleeding due to snake bite. In this
case a whole limb may be swollen, which
does not occur with boomslang and vine
snake bites.
Gaboon adder bites may lead to a
severe consumption coagulopathy as
well as significant swelling.13 These
snakes are placid and only found around
St Lucia in South Africa making bites
decidedly uncommon.
Indications for antivenom and type of antivenom ?
Surgical principles animal bites ?
Rabies * When to suspect rabies ? high risk bite?
* What type of virus ?
* Clinical fatal?
* Mode of transmission ?
* When PEP effective?
* Treatment?
* Dose of IG
* How often to give vaccine
