Australian Doctor 16th February 2024 AD 16th Feb issue | Page 22

22 HOW TO TREAT : MARINE STINGS AND POISONING

22 HOW TO TREAT : MARINE STINGS AND POISONING

16 FEBRUARY 2024 ausdoc . com . au
weakness . Creatine kinase is elevated
because of muscle injury , and in
A
B
severe cases , rhabdomyolysis is complicated
by hyperkalaemia , hypocalcaemia
and acute kidney injury , with
associated myoglobinuria .
Treatment is similar to that for
Australian terrestrial snakes . First
aid consists of a pressure bandage
with immobilisation of the extremity
and whole body . Antivenom is
the mainstay of treatment for systemic
envenomation , and a small
case series supports its effectiveness . 9 Use only sea snake antivenom and not any other snake antivenom .
In severe cases , supportive treatment
is important for electrolyte
abnormalities and acute kidney
injury .
Blue-ringed octopus
Blue-ringed octopuses occur in tidal
areas and rock pools around the coast
of Australia . They are often well camouflaged
until they are disturbed — when their rings change colour dramatically . Their saliva contains tetrodotoxin that is injected when the octopus bites . Bites almost always occur when the creature is picked up and irritated .
Figure 5 . Stingray injury to the dorsum of the foot .
A . Day one .
B . Day three .
Most bites are painless and only
recognised because there is local bleeding . Most cases result in only
A
B
minor effects , with localised or
regional numbness and paraesthesia
. Systemic envenomation is characterised
by flaccid paralysis , which
is identical to tetrodotoxin poisoning
and described later . Treatment is
early basic life support for respiratory
paralysis and immediate transport to
hospital . Pressure immobilisation is recommended but should not prevent basic life support or transport . There is
Figure 6 . Sea urchin injury to the foot .
no antidote for tetrodotoxin , so treatment is supportive , with mechanical ventilation .
Sponges
Sponge injuries differ from other marine injuries because they are
A . This shows the entry wounds .
B . An X-ray of the largest spine before removal .
contact skin reactions rather than penetrating injuries . Injuries are uncommon , with only some species ,
Ciguatera
Ciguatera is by far the most common
such as fire sponges , having toxic
marine poisoning : it is an important
secretions that cause more severe effects . 10 The clinical effects of most sponge injuries tend to be minor ,
health condition in the Indo-Pacific and Caribbean regions , where seafood is the major dietary source of protein .
with local paraesthesia , numbness ,
It is endemic in parts of northern Aus-
itchiness and mild stinging pain .
tralia , but with modern freezer trans-
The effects usually last hours but , in
port and international travel , it can
some cases , may persist for 2-3 days .
occur in any part of Australia .
Most cases only result in erythema , with occasional development of vesicles and blistering .
Ciguatera results from the ingestion of ciguatoxins , which are produced by small marine creatures
Fire sponges , however , differ
( dinoflagellates : Gambierdiscus tox-
because they cause moderate to
icus ) and then accumulate in larger
severe delayed effects that can pres-
tropical reef fish as they travel up the
ent up to 2-3 weeks after contact ,
food chain . Fish typically implicated
with painful swelling and erythema ,
are Spanish mackerel , mackerel , bass ,
followed by desquamation ( see fig-
coral trout , moray eels and species
ure 7 ). Wash the contact area as soon
of cod and emperors . Unfortunately ,
as possible , and treat symptomati-
there is no way to identify if a fish
cally with analgesia and antihista-
contains ciguatoxins , including by
mines . The effects resolve over days to weeks .
MARINE POISONING
MARINE poisoning occurs following
the taste of the fish . Fish in different regions may or may not be affected .
CLINICAL EFFECTS The clinical effects differ between the
Figure 7 . Delayed skin reaction to a fire sponge contact .
the ingestion of marine invertebrates
Indo-Pacific and the Caribbean . In the
( for example , shellfish ) or vertebrates
Indo-Pacific , including Australia , cig-
Neurological effects are generally
paraesthesia , and numbness . Cold
are described , but these are poorly
( large fish ) where these animals have
uatera causes both gastrointestinal
delayed and develop over a period
allodynia is often incorrectly referred
defined and present with less spe-
accumulated toxins from the envi-
and neurological effects . The gastro-
of up to 24 hours . The combination
to as heat reversal but is instead the
cific systemic effects , such as fatigue ,
ronment via the food chain . Gastro-
intestinal effects precede the neu-
of the early gastrointestinal effects
abnormal and unpleasant sensation
loss of energy and depression , as well
intestinal and neurotoxic effects are
rological effects and may initially be
and delayed neurological effects is
when touching cold objects , such as
as gastrointestinal and neurological
the most common clinical manifestations . 1 Marine poisonings , like other causes of food poisoning , are notifia-
like any food poisoning illness , with vomiting , crampy abdominal pain and diarrhoea . These symptoms may
the hallmark of the poisoning . The characteristic neurological effects are a sensory polyneuropathy with
water . More general systemic effects include myalgia , arthralgia and pru-
effects . The diagnosis of ciguatera is clinical , based on the character-
ble diseases in Australia .
resolve after about 12 hours .
cold allodynia , distal and perioral
ritus . Sub-acute and chronic forms
istic combination of the PAGE 24