Gastric secretion and ulceration induced in the rat by an extract from scorpion (B. quinquestriatus) telsons

Role of serotonergic mechanism in gastric contractions induced by Indian Red Scorpion (Mesobuthus tamulus) venom

Aim:

Gastric dysfunctions are commonly seen after scorpion envenomation, and the underlying mechanisms are not clear. Therefore, the present study was undertaken to investigate the effect of Indian red scorpion (Mesobuthus tamulus, MBT) venom on gastric fundus muscle contraction and the underlying mechanisms involved.

Materials and Methods:

In vitro isometric contraction was recorded from gastric fundus muscle strips on a chart recorder. The tissue was exposed to different concentrations of serotonin or crude MBT venom. The contractile responses to venom were expressed as the percentage of maximum contraction produced by serotonin at the beginning of each experiment. The contractile responses to 1.0 μg/ml of crude MBT venom were ascertained in the absence or presence of serotonin antagonist, methysergide.

Results:

Serotonin produced concentration-dependent fundus contractions (0.004–4.0 μM), and maximum contractile response was observed at 4.0 μM of serotonin. Hence, the contractile response obtained at 4.0 μM of serotonin was taken for normalization. The crude MBT venom (0.1–1.0 μg/ml) produced a concentration-dependent increase in fundus contractions (as % of maximum fundus contraction produced by serotonin at 4.0 μM). The maximum response was observed at 1.0 μg/ml of crude venom and a further increase in the concentration, up to 3.0 μg/ml, did not increase the response. In a separate series of experiments, pre-treatment with methysergide (1.0 μM) significantly attenuated the contractile response elicited by the venom (1.0 μg/ml) (P<0.05) and blocked the serotonin (4.0 μM) response.

Conclusion:

The results suggest that the crude MBT venom produces gastric fundus contractions by partially involving serotonin.

Gastrointestinal manifestations in severe scorpion envenomation

OBJECTIVES

To evaluate the type and incidence of gastrointestinal manifestations secondary to scorpion envenomation and their prognostic significance.

PATIENTS AND METHODS

All patients admitted to our ICU for scorpion envenomation were included in this retrospective chart review of a 13-year period (1990 - 2002).

RESULTS

During the study period, 951 patients were admitted for scorpion envenomation and 72 (7.6%) died. Ages ranged from 0.5 to 90 years with a mean of 14.7 +/- 17.4 years. Gastrointestinal symptoms were present in 700 patients (73.6%): nausea in 24 (2.5%), vomiting in 687 (72.2%) and diarrhea in 41 patients (4.3%). At univariate analysis, the presence of diarrhea was associated with a fatal outcome (P < 0.05). Diarrhea was also correlated with other indicators of severe envenomation and poor prognosis: respiratory failure (P = 0.01), neurological failure (P < 0.0001), liver failure (P < 0.0001) and low blood pressure requiring catecholamine support (P = 0.02). The multivariate analysis showed that young age (age less than 5 years), fever > 38.5 degrees C, neurological failure and pulmonary edema were independent factors of severity. Digestive disorders were more frequent in children and in this subgroup diarrhea appeared to be associated with poor outcome. In a subset of patients for whom data were available, fatal cases demonstrated significantly higher liver enzymes levels on admission.

CONCLUSION

In Tunisia, gastrointestinal symptoms are often observed in severe scorpion envenomations, especially in young patients. In children, diarrhea and elevated liver enzymes are associated with poor prognosis.

[Scorpion stings in children. Saudi Arabian experience]

Scorpion stings are a major public health problem in Saudi Arabia. The main victims are children who accidentally tread on a scorpion, about 900 children being admitted to hospitals each summer for such stings. Many cases are fatal. The pathophysiology of scorpion stings is complex and its management is difficult. Almost all body systems are affected but circulatory shock and pulmonary oedema are the usual cause of death. The treatment is based on scorpion antivenom and symptomatic treatment of the envenoming manifestations in an intensive care unit. The currently used antivenom is a polyvalent horse serum preparation given intravenously.

Effect of a scorpion (Leiurus quinquestriatus H and E) venom on blood gases and acid-base balance in the rat

Leiurus quinquestriatus crude venom caused metabolic alkalosis which was partially compensated by respiratory acidosis. Fraction 1 of the venom caused metabolic and respiratory acidosis. The other fractions caused metabolic alkalosis with various degrees of compensation by respiratory acidosis. Fraction 1 caused a marked decrease in blood pH. Hypoxia seemed to be an important contributing factor for this change. Sodium levels decreased while potassium levels increased in the plasma.