Case reports

Australia
Mercer et al. 1981: 1 A. stokesii bite. Identification: morphological.
Audley 1985: 1 A. stokesii bite. Identification: morphological.

Signs & symptoms

Neurological effects

Ptosis developed within 30 s after the mother loosened her grip on the child's lower leg, which had obviously acted like a tourniquet. Directly afterwards respiratory distress developed. Only 4 min after the onset of symptoms (20 min after the bite) the child was cyanotic, unconscious and displayed tonic movements of the extremities. After intubation and under adequate respiration with good circulatory and respiratory conditions, flaccid paralysis and hyperreflexia were present, but not the Babinski sign. 14 h after the bite, after initial improvement of the neurological symptoms under antivenom treatment, spasmodic generalised tonic cramps as soon as the child was touched (Mercer et al. 1981).

Diplopia (Audley 1985).

The venom of some Hydrophiidae (not that of E. schistosa) contains long-chain neurotoxins that bind to the human acetylcholine receptor via tryptophan at position 184 and can have a postsynaptic effect (Harris 1989, Minton 1990).

Muscular effects

After approximately 50 h (after the paralysis of the respiratory musculature had been corrected and the child had already been extubated for approx. 24 h) a marked instability of the lower extremities occurred simultaneously with the maximum CPK level and myoglobinuria (see below). The gait disorder improved within 2 weeks. One month after the bite the child was functioning completely normally again except for an unstable gait when tired (compare Enhydrina schistosa) (Mercer et al. 1981).

Other signs & symptoms

Hallucinations (Mercer et al. 1981), cerebral confusion (Audley 1985).

Morbidity

See above "Signs and symptoms: Muscular effects".

Laboratory and physical investigations

1. Leucocytes

Leucocytosis 27,200/mm³ (Mercer et al. 1981).

2. Myolysis

Serum enymes changes reflecting skeletal muscle damage (without myocardial involvement), maximum approx. 50 h after the bite. At this point myoglobinuria also developed (Mercer et al. 1981).

3. ECG

Normal (Mercer et al. 1981).

First aid

The mother's firm grip on the child's lower leg acted as an efficient tourniquet. Thirty seconds after she loosened her grip the full neurological effects of the venom became apparent (Mercer et al. 1981).

Treatment (symptomatic)

Endotracheal intubation and ventilation.

Treatment (specific)

Antivenoms
Sea snake antivenom (CSL, Parkville, Australia) (Audley 1985, Mercer et al. 1981).
Tiger snake antivenom (CSL, Parkville, Australia) (Audley 1985).
 
Antivenom indications

Neurological effects (ptosis, dysarthria, dysphagia, paralysis of the extremities and the respiratory musculature).

Efficacy

• In both case reports there was improvement in the clinical signs of envenoming coinciding with antivenom administration:
  
  1. Initial dose of 3,000 IU and a further 4,000 IU of Sea snake antivenom (CSL) after renewed deterioration 14 h after the bite. The child was able to be extubated 22 h after the bite, and spoke with her mother 24 h after the bite and was able to sit with support. However, the spasmodic movements started again as soon as the child was touched (Mercer et al. 1981).
  2. 1 vial of Sea snake antivenom (CSL) and 1 vial of Tiger snake antivenom (CSL). The patient was free of symptoms the same day (Audley 1985).

• In vitro and in vivo comparisons of the efficacy of 4 antivenoms (Baxter and Gallichio 1974, 1976) (see Enhydrina schistosa).