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Results Out of 60 patients, 40 were males and 16 were females; showing a male to female ratio of 2.7:1. The mean age of the study group was 33.8 (SD 11.9 ) years. The bite types were as follows:- 54% Russell’s viper bite,31% common krait bite, and 7% cobra bite (Table 1). Sixty eight percent (41 patients) showed a reaction: mild reaction in 58% (24), a moderate reaction in 36%(15), and a severe reaction in 5%(2). The development of hypotension was not seen in any patients. The mean time for the onset of reactions with AVS was 40 (SD 16.2) minutes. The mean time duration of reactions after treatment with counter medications for reaction was 21.7 (SD 17.3) minutes. The distribution of onset of the reaction and the recovery rate is illustrated in Table 2. The frequency and the pattern of reaction observed in the 60 patients under consideration is given in Table 3. A first dose of 10 vials of AVS per patient was given to 47 patients, 64% of them developed reactions. In 2 patients the reaction was severe. In 13 patients with severe envenoming who were given a first dose of 20 vials the reaction rate was 84%. There was no significant difference in the rates of reactions seen when 10 vials and 20 vials were used as first dose (Chi square = 2.03, p > 0.05). This observation indicates that the reaction was not directly dependent on the dose of AVS administered. |
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Twenty patients out of the sample studied,
were transferred from peripheral hospitals after an initial sub-therapeutic
dose of AVS varying from 1-10 vials had been administered. Out of them
9 developed reactions to first dose of AVS given at General Hospital,
Anuradhapura (reaction rate 45%). This result is a statistically significant
reductions of reaction to repeated AVS administration (Chi square =
7.54, p = 0.006). Similarly a second dose of AVS had to be given to
11 patients (total sample 60) at General Hospital, Anuradhapura due
to persisting envenoming and only 5 of them developed a mild reaction
(reaction rate 45%). This observation further suggests a reduction of
reaction rate with repeated AVS administration.
Patients who were treated with intravenous doses of 400mg hydrocortisone and 10mg chlopheniramine, at the on set of reaction showed a good response (Table 2). Patients with vomiting (n=9) responded to metochlopramide 10 mg given intravenously. Bronchospasm was relieved with nebulized salbutamol (n=2). Severe reaction (n=1), when treated with adrenaline (0.5 ml, 1: 1000) subcutaneously showed a quick response within 15 minutes. Patients with poor response to initial treatment, who went on to develop subsequent severe reactions were administered 1000mg hydrocortisone continuously. |
Table 1: Age and sex distribution of patients and the type of snake bite
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Age (Years)
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Sex
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Type of snake bite
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M
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F
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Viper
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C krait
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Cobra
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10 - 19 20 - 29 30 - 39 40 - 49 >50 Total |
7 11 11 11 4 44 |
- 4 4 8 - 16 |
5 11 11 13 1 41 |
2 3 3 5 3 16 |
- 1 1 1 - 3
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