24 HOW TO TREAT : MARINE STINGS AND POISONING
24 HOW TO TREAT : MARINE STINGS AND POISONING
16 FEBRUARY 2024 ausdoc . com . au
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gastrointestinal and neu- |
encephalopathic shellfish poisoning . 1 |
rological effects after eating fish |
Amnesic shellfish poisoning is the |
known to be implicated in ciguat- |
fourth type and is extremely rare . |
era . The diagnosis of the sub-acute and chronic forms is more difficult . Although ciguatoxins can be detected |
Scombroid
Scombroid differs from other marine
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in fish , it is not possible to detect the |
poisonings and is clinically similar to |
small amounts that cause ciguatera in |
an allergic reaction . It is due to the |
humans . |
ingestion of fish containing high concentrations |
TREATMENT |
spoilage from poor storage . Fish from |
The treatment for ciguatera is support- |
the Scombridae family are most com- |
ive and symptomatic because there is |
monly implicated , including kingfish , |
no specific antidote for the toxin . Rehy- |
tuna , mackerel and wahoo . |
dration with standard IV fluids is the |
most important treatment , like with |
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CLINICAL EFFECTS |
most gastrointestinal poisonings . Man- |
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Although similar to a hypersensi- |
nitol has not been shown to be effec- |
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tivity reaction , the effects are only |
tive . NSAIDs can be used for analgesia . |
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caused by histamine . Patients will |
Although numerous medications have been tried for the chronic form , there is little evidence to support their use . |
Figure 8 . Toadfish . |
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have a combination of gastrointestinal effects ( nausea , vomiting , abdominal pain and diarrhoea ), skin effects |
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Tetrodotoxin poisoning
Tetrodotoxin ( TTX ) occurs in numer-
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are present , will cause failure of nerve conduction and a sensorimotor |
there will be cardiovascular toxicity with bradycardia , arrhythmias and |
2-5 days . Symptomatic bradycardia is treated with atropine , and fluid resus- |
( urticaria , diffuse erythema , flushing and pruritus ) and headache . In more severe poisoning , there will |
ous types of fish , including puffer |
neuropathy . |
hypotension . TTX does not cross the |
citation may be required . |
be hypotension and , rarely , respira- |
fish , and occurs more commonly in South-East Asia . TTX poisoning is rare in Australia but occurs with |
CLINICAL EFFECTS TTX poisoning develops within min- |
blood – brain barrier , so there is no effect on the CNS , and importantly , patients will remain aware despite |
Shellfish poisoning
Shellfish poisoning is rare in Aus-
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tory effects . The effects develop over 30-60 minutes and generally resolve within 4-6 hours . The diagnosis is |
ingestion of toadfish ( see figure 8 ) and related types of fish . 11 Most cases occur when the fish is caught and |
utes to hours of ingestion and develops more rapidly in severe cases with larger ingestions . Sensory effects |
having severe paralysis . This is why sedation is essential and staff need to be aware that patients are conscious . |
tralia because of the increased controls of fisheries around the country . It is far more common to get viral |
clinical and can be confirmed with the detection of high concentrations of histamine in the fish . |
eaten by a group of people who do |
include paraesthesia and numbness , |
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and bacterial infections from shell- |
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not realise it is poisonous . In Japan , |
followed by motor effects with ataxia |
TREATMENT |
fish ingestion than poisoning . Three |
TREATMENT |
TTX poisoning occurs when puffer |
and then progressive distal to proxi- |
There is no specific antidote for TTX |
of the four types of shellfish poison- |
Treatment is with antihistamines , |
fish is incorrectly prepared and then eaten ; this referred to as fugu |
mal muscle weakness . Initially , there may also be mild gastrointestinal |
toxicity , and treatment is supportive . Pre-hospital treatment in severe |
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ing are neurotoxic in nature , including paralytic shellfish poisoning from |
both H 1 and H 2 antagonists — promethazine 50mg and either famotidine |
poisoning . |
symptoms , with nausea and vomit- |
cases requires early basic life support |
toxins similar to TTX ; neurotoxic |
or nizatidine , unlike the primary use |
TTX is a sodium-channel blocker |
ing . Severe poisoning causes respira- |
and then intubation and ventilation . |
shellfish poisoning , causing neuro- |
of adrenaline for acute anaphylaxis . |
and , if sufficient enough amounts |
tory muscle paralysis . In rare cases , |
Most patients will need ventilation for |
excitatory effects ; and the very rare |
Administer salbutamol for bronchospasm |
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and IV fluids for hypotension . |
How to Treat Quiz .
GO ONLINE TO COMPLETE THE QUIZ ausdoc . com . au / how-to-treat
1 . Which THREE statements are correct ? a Marine poisoning occurs when a marine creature containing toxic substances is ingested . b Jellyfish cause stings when their tentacles contact skin . c Major box jellyfish and stingray injuries are common in Australia in the summer . d Most jellyfish stings are minor .
2 . Which ONE is not a common feature of linear tentacle-like jellyfish stings ? a Stings result from contact with the tentacles . b Immediate local pain lasting minutes to hours . c Non-specific systemic effects , including nausea , vomiting and malaise . d Linear erythematous or urticarial eruptions .
3 . Which TWO are appropriate first-aid treatment for a bluebottle sting ? a Remove the tentacles — either by washing them off with fresh water or picking them off carefully . b Hot water immersion ( 45 ° C ) for 20 minutes is the recommended treatment for local pain . c Do not apply vinegar to the sting as this may increase the pain .
d Applying an ice pack for 20 minutes is the recommended treatment for local pain .
4 . Which THREE statements regarding the major box jellyfish are correct ? a IV antivenom is the most important aspect of resuscitation . b Most stings are minor , but severe and life-threatening stings occur with greater skin contact with the tentacles . c Pre-hospital resuscitation is key . d Severe envenoming is characterised by rapid onset of cardiovascular collapse and death within 20-30 minutes .
5 . Which TWO statements regarding Irukandji syndrome are correct ? a Most cases do not require medical treatment . b It is classically associated with stings from C . barnesi . c The pain almost always requires IV opioid analgesia . d Most stings are due to contact with the tentacles .
6 . Which THREE are appropriate treatments for penetrating marine injuries ? a Immerse in hot water , about 45 ° C , for a maximum duration of 90 minutes . b Antibiotics for all penetrating marine injuries . c Review all penetrating marine injuries every 24-48 hours for the first week . d Oral or titrated parenteral analgesia and occasionally local or regional anaesthesia for severe pain .
7 . Which TWO statements are correct ? a Antivenom is the mainstay of treatment for systemic sea snake envenomation . b Systemic envenomation from sea snakes usually causes neurotoxicity . c The saliva of the blue-ringed octopus contains tetrodotoxin that is injected when the octopus bites . d Sponge injuries , although uncommon , usually result in severe local and systemic effects .
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MARINE STINGS AND POISONING
8 . Which THREE statements regarding ciguatera are correct ? a Ciguatoxins impart a metallic taste to the fish , an indication not to eat it . b The combination of the early gastrointestinal effects and delayed neurological effects is the hallmark of the poisoning . c The characteristic neurological effects are a sensory polyneuropathy with cold allodynia , distal and perioral paraesthesia , and numbness . d The treatment for ciguatera is supportive and symptomatic because there is no specific antidote for the toxin .
9 . Which THREE are features of tetrodotoxin poisoning ? a Paraesthesia and numbness . b Delirium . c Initial mild gastrointestinal symptoms . d Progressive distal to proximal muscle weakness .
10 . Which THREE statements regarding shellfish poisoning are correct ? a Scombroid develops over 4-6 hours . b Shellfish poisoning is rare in
Australia . c Scombroid is clinically similar to an allergic reaction . d Treat scombroid with antihistamines and salbutamol IV fluids as indicated .
CASE STUDIES
Case study one
ANGIE , a five-year-old girl , runs out of the water at the beach screaming and holding on to her left wrist . The wrist has a narrow red line across it .
This is most likely a bluebottle sting . First aid is immersion of the wrist in hot water for 20 minutes . The pain will usually resolve after this , and Angie will not require further medical attention or transport to hospital .
Case study two
Erik , a 25-year-old male , presents to his GP with “ something in the sole of his foot ” after standing on something in the ocean . He only has moderate pain except when he weight-bears , and there is no obvious swelling .
The most likely diagnosis is sea urchin spines in his foot . An ultrasound and X-ray are appropriate .
Superficial spines can usually be easily removed . However , deeper ones require follow-up and possibly surgical removal if they continue to cause symptoms .
CONCLUSION
MARINE bites and stings are uncommon conditions , but this varies by geographical location and season . GPs working in coastal areas will need to treat these conditions mainly in the warmer months .
Most require simple supportive measures , including first aid , analgesia and cleaning of wounds . More unusual cases and major injuries can be managed in conjunction with the Poisons Information Centre ( 131 126 ) or appropriate specialist care : surgical or infectious diseases .
References Available on request from howtotreat @ adg . com . au