Snake/Arthropods/marine Flashcards
40 year old male, sleeping on ground, wakes in night with chest pain, SOB and abdo pain, by morning paralysis. ∆?
Nocturnal paralytic krait bite (Bungarus)
2 main snake families
Viperidae - vipers, adders, moccasins, rattlesnakes, pit vipers - short thick body, short tail, slow movement, sharp movement
Elapidae - cobras, kraits, mambas, corals, venomous sea snakes - relatively long thin body, long- tail, uniformly coloured (except corals), some spread hood, fast
minor families of snakes?
Atractaspididae - burrowing asps
Colubridae - most common - non front fanged
4 main families of protein/polypeptide in venom?
*Phospholipases A2
* Metalloproteases
* Serine proteases
* Three-finger toxins (neuro, cyto)
Clinical effects of envenoming?
Cytotoxicity - local effects
Haemotoxicity
Neurotoxicity
CVS toxicity
Renal toxicity
Myotoxicity
Common snakes causing cytotoxicity?
cobras, vipers, burrowing
asps
Common snakes causing haemotoxicity?
vipers, Oceanian elapids,
a few colubrids
Common causes of haematotoxicity?
Elapids, some vipers
Hypovolaemic shock and myocardial toxicity - which snake?
Vipers
Most likely to cause rhabdo?
Sea snakes
First aid for snake bite?
Pressure pad immobilisation over site of venom depot
Key priniciples in management snake bite?
observation for 24 hrs
Assess and resuscitate
Toxoid
Antivenom IV
Treat bitten limb
Different types of antivenom?
*Polyspecific antivenoms: raised against venoms of the species of greatest medical importance in that region
*Monospecific antivenoms: raised against the venom of one species
Indications for antivenom?
Organ failure
Local swelling
What to give before antivenom?
Prophylactic small dose of adrenaline
Biggest problem with antivenom?
Anapylaxis
Late serum-sickness-type reactions
Another symptomatic Rx for snake bite?
Anticholinesterase (give with antimuscarininic)
Prevention of snake bites?
wearing protective footwear, using a light after dark,
sleeping off the ground or under a mosquito net
When do you repeat a dose of antivenom?
failure of restoration of blood coagulability after 6 h, or progression of other signs of envenoming
What to consider for bitten limb?
surgical debridement. antibiotics
Signs of compartment syndrome may be
misleading; fasciotomy is rarely justified.
Bite from a viperidae?
Viperidae (vipers, adders, and pit vipers—rattlesnakes, moccasins, lanceheads)
can cause severe local swelling, bruising, blistering, and necrosis together with
shock, coagulopathy, spontaneous systemic bleeding, acute kidney injury, and, in a few species, neuromyotoxicity
Bite from an elapidae?
Elapidae (cobras, kraits, mambas, coral snakes, Australian snakes, and sea
snakes) can cause descending flaccid paralysis, starting with bilateral ptosis and
progressing to bulbar and respiratory paralysis. Some elapid venoms cause local
necrosis (cobras), rhabdomyolysis (sea-snakes) and haemostatic disturbances
(Austro-Oceanian elapids)
Bite that causes intense local pain, likely bitten by what?
Scorpion
What happens physiologically following sting from scorpion?
- parasympathetic - salivating, lacrimating, vomiting
- sympthathetic - sweating, myocarditis and HR BP up
- Neurotoxic effects - spasms, fasciculation’s
What is this?
Loxosceles bite
Pattern of disease loxosceles bite
Initial local pain and swelling but develop slowly!
Red/white/blue sign
Systemic symptoms
Local necrosis and black ulcer
Rarely progress to fever, jaundice, haemolytic anaemia
Neurotoxic araneism what is pathopneumonic?
Local swelling, erythema, sweating, paraesthesia,
fasciculations - AT SITE OF BITE
PROGRESSES TO Tachycardia, hypertension, agitation, vomiting, salivation
Which spider causes truisms?
Black widow (Latrodectus indistinctus) bites
Most toxic spiders in world?
Australian funnel web - Atrax, Hadronyche
Cause autonomic storm
Neurotoxic araneism caused by?
black and brown widow spiders
(Latrodectus), Latin American banana spiders (Phoneutria), and Sydney/Australian funnel-web spiders (Atrax, Hadronyche)
2 broad syndromes of spiders
Neurotoxic and necrotoxic
Management of marine stings with fish, sea urchin or jelly fish?
Immerse stung part in hot, not scalding, water! (<45) water
Jellyfish sting - how do you know it is a jelly fish?
Local: intense pain, wheals (diagnostic patterns),
swelling, erythema, vesiculation, necrosis, scarring
Fish stings and sea urchins cause?
Local effects only
Difference in timing of seafood poisoning?
Onset in 1-120 mins: scombroid
Onset 10-180 mins: puffer fish
30-180 mins: shellfish
60 min - 24 hrs: ciguatera
Nausea, vomiting, abdo pain with change in temperature in limbs and on drinking, paraesthesia. ∆? What causes the pathology?
Ciguatera fish poisoning
Sodium channel blockage
Commonest cause of non bacterial fish poisoning? Toxin?
Ciguatera
Ciguatoxins
Which fish cause ciguatera?
Reef fish
High risk: moray eel, parrot fish, trigger fish
Which fish do scombroid come from?
Mackerel, yellow fin tuna
Immediate symptom of scombroid?
Periorbital tingling
Cause of scombroid?
Histamine release - cause metabolism of histidine to histamine due to bacteria in the fish.Cooking fish does not prevent it.
Deadliest fish toxin? How does it present?
Puffer fish tetrodotoxin - FUGU poisoning
Generalised rapidly progressing paralysis
Symptoms of scombroid?
vomiting and diarrhoea, pruritus, urticaria, throbbing headache,
bronchospasm, burning throat, angioedema, facial swelling,
Spectrum of shellfish poisoning?
Paralytic, amnesic, neurotoxic, diarrhoeal
Neurotoxic and paralytic forms come from dinoflagellates from ‘red tide’
Management of ciguatera poisoning?
IV mannitol
Management of scombroid poisoning?
antihistamines and adrenaline
Management of paralytic shellfish poisoning?
Supportive
