Is it an Emergency?

Inquire

• time of the bite,
• local pain,
• nausea, vomiting, abdominal pain.

Assess

• state of consciousness.

Measure

• blood pressure/pulse,
• respiratory rate,
• oxygen saturation (pulse oximeter),
• urinary output.

Observe/investigate

• bite marks,
• extent and intensity of local swelling,
• cranial nerve deficits, such as ptosis, ophthalmoplegia, dysphagia, dysarthria,
• paralysis of the skeletal musculature including the respiratory musculature (→ respiratory insufficiency/respiratory failure),
• myalgia with active and passive movement and upon pressure,
• pseudotrismus,
• muscle spasms,
• dark-brown/red urine (rhabdomyolysis!),
• flank pain and renal bed sensitive to percussion.

The fact that a patient has been bitten by a sea snake and the presence of bite marks do not automatically allow the conclusion that a clinically relevant injection of venom has taken place [39 of 55 Enhydrina schistosa (=Hydrophis schistosus) bites, 11/14 Hydrophis cyanocinctus bites and 6/9 Hydrophis spiralis bites did not involve a clinically relevant injection of venom (Reid 1975a,b,c)].
Local signs, such as swelling and pain at the site of the bite, are usually absent and thus completely unreliable as clinical indicators of an injection of venom.

There seem to exist 2 forms of Hydrophiidae envenoming with different courses:

1. primarily myotoxic envenoming (e.g. Enhydrina schistosa =Hydrophis schistosus): signs and symptoms arising in the skeletal musculature; secondary effects of rhabdomyolysis: dark urine (myoglobinuria), acute renal failure, cardiac dysrhythmias (hyperkalaemia);
   EMG-findings indicate a myopathy (Sitprija et al. 1971). The species of sea snake that caused both these accidents were not identified.
   E. schistosa (=Hydrophis schistosus): the venom contains only short-chain neurotoxins that require tryptophan at position 187 of the acetycholine receptor in order to be effective. This is not present in humans. This makes it clear that the venom of E. schistosa (=Hydrophis schistosus) cannot cause primary neurotoxic effects in humans, in contrast to many animals (Harris 1989, Minton 1990). However, in human envenoming a myotoxic phospholipase A is active, which causes the clinical signs and symptoms in the skeletal musculature (Fohlman and Eaker 1977).
2. neurotoxic/(myotoxic) envenoming (e.g. Hydrophis stokesii (described as Astrotia stokesii) and Laticauda colubrina): initially prominent are acute neurotoxic symptoms that occur a short time after the bite and their corresponding signs: ptosis, ophthalmoplegia, dysphagia, dysphonia; progressive paralysis of the respiratory musculature with respiratory insufficiency and failure.

Monitoring for signs and symptoms that would indicate systemic envenoming for at least 12h. 

According to observations by Reid in Penang (Malaysia) severe envenoming can be excluded if there is no skeletal muscle pain upon movement 2 h after the bite (Reid 1979). However, these observations were made chiefly in patients who had been bitten by Enhydrina schistosa (=Hydrophis schistosus).

At least hourly

• state of consciousness,
• heart rate and rhythm,
• blood pressure,
• respiratory rate,
• symtoms & signs of rhabdomyolysis,
  • myalgia with active and passive movement and upon pressure,
  • pseudotrismus,
  • muscle spasms,
  • colour of urine,
  • flank pain and renal bed sensitive to percussion (acute renal failure)
• signs and symptoms of paralysis,

• other newly appearing signs and symptoms.

6-hourly (or more frequently if there is cause for suspicion)

• CK, GOT (AST)
• myoglobinuria,
• urine output.