Envenoming by the rattlesnake Crotalus durissus ruruima in the state of roraima, Brazil

Abstract

The aim of this study was to evaluate the clinical-epidemiological factors associated with victims of rattlesnake envenoming in the state of Roraima, Brazil. In this location, rattlesnake accidents are caused by the subspecies Crotalus durissus ruruima . This is a prospective observational study carried out at the General Hospital of Roraima from april 2017 until july 2018. A total of 37 alleged rattlesnake victims had their medical records evaluated. However only one of them proved to be by C. d. ruruima . All individuals were residents from the savannas (lavrados) of Roraima. The town of Bonfim on the border between Brazil and Guyana had the highest occurrence of rattlesnake bites. The most affected group were males aged 13–20 years and farmers. The highest number of incidents occurred during daytime and lower limbs (feet) were the most major affected part of the body. Tourniquets were used as first aid after snake envenoming in 32.4% of victims. Out of 37 patients, 16.2% were classified as severe cases of snakebite envenoming and in 5.4% dry bites seem to have occurred. Among the symptomatic patients, 100% presented local manifestations and 70.3% presented systemic manifestations. The clinical setting showed local effects such as pain and edema while the systemic effects were blurred vision, myalgias, myasthenic facies, palpebral ptosis, muscle weakness and headache. Laboratory results of aspartate aminotransferase (62.2%), creatine phosphokinase (51.3%), lactic dehydrogenase (37.8%), urea level (32.4%) and serum creatinine (29.7%) were increased significantly in relation to the reference standards. In 16.2% of the cases, the victims presented acute kidney injury. Patients were treated with anticrotalic serum in 70.3% of the cases and antibotropic + anticrotalic serum in 24.3%. The victims of C. d. ruruima in Roraima showed a local symptomatology similar to Bothrops envenoming, while systemic symptoms and laboratory analysis proved kidney and muscular injuries, similar to envenoming by Crotalus d. terrificus in Brazil.

Crotalus Durissus Ruruima: Current Knowledge on Natural History, Medical Importance, and Clinical Toxinology

“…Most of the snakebites occurred in the lower (85.6%) and upper limbs (13.1%) ( Table 2 ). This epidemiological profile confirms small case series previously published in the state of Roraima ( 25 , 26 , 115 ). Asato and colleagues showed that the C. ruruima envenomings attended to in Boa Vista, the capital of the state of Roraima, predominantly involved farmers during morning or afternoon work in their fields ( 26 ).…”

“…In this situation, where the snake is partially covered by vegetation, its visual detection becomes more difficult ( 24 ). Thermoregulation constitutes the main diurnal activity of nocturnal Viperidae snakes ( 20 , 24 ), which may explain most cases of snakebite in Roraima state, since this period is also that of human activity in the area ( 25 , 26 ).…”

“…This coefficient is determined through the ratio of average venom LD 50 and the neurotoxins concentration (crotoxin and crotamine) ( 5 ). This fact could justify the severe cases of envenoming and lethality caused by C. d. ruruima snakes ( 26 , 59 ).…”

“…However, the few reports suggest some differences in relation to the clinical pictures resulting from different subspecies of C. durissus found in South America. The main difference pointed out is the high frequency of inflammatory manifestations at the bite site and coagulopathy ( 26 , 115 ). However, the small number of published cases prevents a more accurate comparison with data from other regions.…”

“…Unfortunately, paresthesia is not reported by SINAN but is also a very common manifestation in Crotalus bites. In C. d. ruruima envenomings, paresthesia frequency ranges from 12.5 to 16.2% ( 26 , 115 ). In the state of São Paulo, paresthesia was reported in 47.6% of the children ( 117 ) and 26.1% ( 116 ) of the general cases of Crotalus bites.…”