Lesiones por Raya de Río: Acerca de tres casos en el Río de la Plata, Argentina / Injuries caused by River Stingrays:About three cases in the Río de la Plata ("River Plate") river, Argentina

Resumen Las rayas del género Potamotrygon son peces con forma dorsoventral aplanada. Son animales tranquilos, que solo atacan al ser agredidos o amenazados. Poseen en su cola estructuras punzantes, conocidas como espinas, envueltas por una vaina tegumentaria con tejidos secretores de componentes tóxicos. Suelen permanecer quietos en aguas superficiales, ocultos bajo arena o barro, lo que facilita su contacto accidental con humanos, con la probable generación de lesiones, al utilizar su cola hacia arriba y adelante en forma de látigo. Las lesiones son más frecuentes en hombres, en los meses estivales y en los miembros inferiores, seguidos por los miembros superiores. La lesión se asocia a dolor urente, casi inmediato y de gran intensidad, por el efecto traumático generado por las espinas, la persistencia de las mismas o sus fragmentos y por el efecto químico generado por sus toxinas. En ocasiones se asocia a la formación de necrosis y úlceras profundas o reacción granulomatosa por cuerpo extraño, con requerimientos de desbridamiento quirúrgico. Las lesiones fatales son infrecuentes y pueden resultar de una lesión torácica penetrante, laceraciones cervicales, compromiso de vía aérea, heridas vasculares o infecciones. Se deben realizar estudios de imágenes para evidenciar restos de la espina. La herida debe ser higienizada y se debe retirar la espina o sus fragmentos a la brevedad y sumergir el área lesionada en agua tan caliente como el paciente pueda tolerar, por 30 a 90 minutos, buscando disminuir el dolor y generar vasodilatación, junto con la analgesia y cobertura antibiótica y antitetánica. Se presentan tres casos de pacientes con lesiones por raya de río, dos de ellos por Potamotrygon brachyura, especie endémica del río de La Plata y el tercero por una raya no identificada. Se expone además una revisión bibliográfica a fin de remarcar la importancia de su diagnóstico temprano y su correcto abordaje.

Abstract The rays of the Potamotrygon genus are fish with a dorsoventrally flattened shape. They are calm animals that only attack when are provoked or threatened. They have sharp structures in their tail, known as spines, wrapped by a tegumentary sheath with tissues that secrete toxic components. They typically remain still in shallow waters, concealed under sand or mud, which increases accidental human contact. This contact can lead to injuries, as they whip their tail upwards and forwards. Injuries are more common in males during summer months, often affecting lower limbs followed by upper limbs. Injuries are characterized by immediate intense burning pain due to trauma from the spine or its fragments and chemical effects from its toxins. Occasionally, injuries lead to necrosis, deep ulcers, or foreign body granulomatous reactions requiring surgical debridement. Fatal injuries are rare but can result from thoracic penetration, cervical lacerations, airway compromise, vascular wounds, or infections. Imaging studies are necessary to detect spine remnants. Wounds should be cleaned, and spines or fragments removed promptly. The affected area should be immersed in water, as hot as tolerable for 30 to 90 minutes to reduce pain, induce vasodilation, and must supplemented with analgesia, antibiotic coverage, and tetanus prophylaxis. Three cases of river stingray injuries are presented, two from Potamotrygon brachyura, an endemic species of the Rio de la Plata river, and one from an unidentified ray. Additionally, a literature review emphasizes the importance of early diagnosis and proper management.

Plantas tóxicas: asclepia, ricino y oreja de elefante (alocasia) / Poisonous plants: milk weed, castor bean and elephant ear plant (alocasia)

Resumen Se describirán y verán imágenes de 3 especies vegetales tóxicas (Asclepia, Alocasia y Ricino) comunes de encontrar en paisajes urbanos (jardines, parques, terrenos baldíos, viveros). Por su apariencia atractiva y accesibilidad resultan en contactos o ingestas accidentales en niños, incluso en animales domésticos. Sus principios activos pueden causar cuadros clínicos de variable severidad. Resulta importante la identificación de estas especies para facilitar el diagnóstico y el tratamiento a la hora de la consulta.

Abstract Images of 3 toxic plant species (Asclepia, Alocasia and Castor) that are common to be found in urban landscapes (gardens, parks, vacant lots, plant shops or greenhouses) will be described and seen. Due to their attractive appearance and accessibility, they result in accidental contact or ingestion in children, even in domestic animals. Its xenobiotics can cause poisonings of variable severity. It is important to identify these species to facilitate diagnosis and treatment at the time of consultation.

Intoxicación severa por Nicotiana glauca (Palán Palán) con miocardio atontado / Severe poisoning by Nicotiana glauca (Palán Palán) with stunned myocardium

Resumen Nicotiana glauca también llamada Palán Palán, es un arbusto con hojas verdes azuladas y despulidas y una flor amarilla tubular pendulante que presenta alcaloides piridínicos, como nicotina, nornicotina, anatabina y anabastina (análogo estructural de la Nicotina). Se presenta el caso clínico de una paciente de 50 años con cuadro agudo de debilidad muscular generalizada que evoluciona con paro respiratorio, tras la ingesta accidental de una cantidad desconocida de hojas de Nicotiana glauca, cultivadas en una huerta hogareña mediante técnica de hidroponía y confundidas por su conviviente con espinaca. Presentó aumento de lactato y Troponina Ultra Sensible e Hipoquinesia Global de Ventrículo Izquierdo en el ecocardiograma, compatible con Aton tamiento Miocárdico (AM), que evolucionó favorablemente. Si bien hay pocos reportes, se han informado muertes de animales y humanos, tras la ingesta accidental de Nicotiana glauca. El inicio del cuadro es rápido, con patrón bifásico, con vómitos y estímulo simpático, seguido por bloqueo ganglionar y neuromuscular, pudiendo presentar paro respiratorio, shock, convulsiones y coma. El AM es una disfunción miocárdica prolongada con retorno gradual de la actividad contráctil, posterior a un episodio breve de isquemia grave, puede ser asintomático, pudiendo presentar alteraciones en el electrocardiograma, enzimas cardíacas o ecocardiograma. Generalmente presenta pronóstico favorable, pudiendo presentar insuficiencia cardíaca ante patologías concurrentes o aumento de requerimientos de oxígeno.

Abstract Nicotiana glauca is a shrub with bluish green leaves and a pendulous tubular yellow flower. It has pyridine alkaloids, such as nicotine, nornicotine, anatabine and anabastine (structural analog of Nicotine). We present the case of a 50 years old pa- tient with acute generalized muscle weakness that evolves to respiratory arrest, after accidentally ingesting an unknown quantity of Nicotiana glauca leaves, grown in a home vegetable garden, using a hydroponic technique and confused by her cohabiting with spinach. She presented increased lactate and Ultra Sensitive Troponin and Left Ventricular Global Hypokinesia in the echo- cardiogram, compatible with Myocardial Stunned, that it evolved favorably. There are few reports, animal and human deaths have been reported following accidental ingestion of Nicotiana glauca. The onset of the symptoms is early, with a biphasic pattern, with vomiting and sympathetic stimulation, followed by ganglionic and neuromuscular blockage and may present respiratory arrest, shock, seizures and coma. Myocardial Stunned is a prolonged myocardial dysfunction with gradual return of contractile activity after a brief episode of severe ischemia, it can be asymptomatic, and it can present alterations in the electrocardiogram, cardiac enzymes or echocardiogram. Generally presents a benign prognosis, being able to present heart failure with concurrent patholo- gies or increased requirements.

Intoxicación aguda con monóxido de carbono (ICO) secundaria a pipa de agua (Narguile). Reporte de un caso / Carbon monoxide poisoning caused by water pipe smoking (Narghile). A case report

Resumen Dentro de las formas alternativas de consumo de tabaco, se describe el uso de pipas de agua (también llamadas hookah, shisha o narguile) como implementos de uso. Esta forma de uso es una forma emergente en nuestro medio, con uso en estudiantes universitarios y secundarios. Debido a que utiliza carbón para quemar el tabaco, junto a largos períodos de uso, presenta riesgo de intoxicación por monóxido de carbono, especialmente si se utiliza en ambientes cerrados. En este artículo presentamos el caso de una paciente femenina de 19 años, quién fue traída al hospital con una intoxicación grave por monóxi do de carbono secundaria a uso de pipa de agua, requiriendo tratamiento con oxígeno en cámara hiperbárica. Realizamos una revisión de la bibliografía.

Abstract Amongst the alternative ways of tobacco use, water pipes (also called hookah, shisha or narghile) have been used as implements. This type of use is an emergent one in our environment, being used by high school and college students. Due to the use of charcoal as a way to burn the tobacco, and the long using times it presents, the users are at risk of being poisoned by carbon monoxide, especially if they smoke in enclosed spaces. In this paper, we present the case of a 19-year-old female patient, who was brought to the hospital with a severe case of carbon monoxide poisoning, requiring treatment with oxygen in a hyperbaric chamber. We make a review of the literature.

Variaciones de caracteres morfológicos dentro de la especie Bothrops alternatus / Morphological characters variations within the Bothrops alternatus species

Resumen El género Bothrops (yarará) es responsable de más del 95% de los accidentes por ofidios venenosos en Argentina. La mayoría de éstos son notificados en provincias del Nordeste y Noroeste. Bothrops alternatus, es la especie más frecuentementehallada, siendo el vipérido de gran talla más meridional del mundo y una de las especies de mayor importancia sanitaria en Argentina, pudiendo hallarse en relación a núcleos urbanos. Presentan en el dorso figuras arriñonadas características, que remedan atubos de teléfono o porotos unidos, completos o incompletos, hasta la forma fusionada. Presenta foseta loreal, órgano termore-ceptor ubicado entre el ojo y la fosa nasal. Su dentición es solenoglifa, dientes inoculadores huecos, con conducto cerrado, fijosa un hueso maxilar móvil. Si bien se describen variaciones entre animales, se considera una especie monotípica. Su identificaciónes importante dada la abundancia de especímenes y de hallazgos en regiones periurbanas.

Abstract The Bothrops genus is responsible for more than 95% of ophidian accidents in Argentina, most of these are reported in the Northeast and Northwest provinces. Bothrops alternatus, is the most frequent species of the genus Bothrops (yarará), themost southern large-scale viperid in the world and one of the most important species in Argentina, being able to be found in rela-tion to urban nucleus. Their characteristic features are kidney-like figures in the skin, that mimic phone tubes or beans, completeor incomplete, until the merged form. It presents a loreal pit, thermoreceptor organ located between the eye and the nostril. Itsdentition is solenoglyphous, hollow inoculating teeth, with closed duct, fixed to a mobile maxillary bone. Although variationsbetween animals are described, it is considered a monotypic species. The identification of this snake is important due their abun-dance in around urban regions and its frequency of finding.

Study on the obtaining of Tityus trivittatus venom in Argentina.

Envenomation by scorpions of the genus Tityus is an important public health problem in Argentina, involving near 8000 stings and 2 deaths each year. Treatment for envenomation is the use of specific antivenom and intensive hospital care. Antivenom is produced by the Ministry of Health and freely distributed throughout the country. For antivenom production it is necessary to collect scorpion venom, which is a difficult task because although scorpions can be found in Argentina, they are less abundant than in warmer latitudes. For this reason venom collection constitutes a bottleneck for antivenom production. Although in Argentina several species of Tityus can be found, most of the accidents are caused by Tityus trivittatus, and the venom of this scorpion has historically been the venom used for antivenom production. We analyzed retrospectively 26 pools of telson homogenates (6964 telsons) and 37 pools of milked venom obtained by electrical stimulation (equivalent to 6841 milkings). Lethal potencies of samples from different provinces were very similar, although venom from scorpions of Buenos Aires city showed the lowest potency. The venom obtained by milking (median LD50 12.3 µg), provided batches containing LD50s more potent when compared with the venom obtained from telson homogenates (p < 0.0001). Many batches of telson homogenates (30%) showed lower potencies than acceptable for antivenom production and control. In addition to the study of the venom yield, the records of immunization of horses, the potency of the batches and the protein content of each batch of anti-scorpion antivenom produced were analyzed, comparing those produced using milked venom with those using telson homogenates as immunogens. Batches produced using milked venom required a shorter period of immunization (p < 0.0001), rendered higher neutralizing titers (p 0.0350) and possessed lower protein content (p 0.0092). Results clearly showed that the milking of scorpions is a more efficient tool to obtain venom for antivenom production in comparison to the use of telson homogenates.

Antivenom against Crotalus durissus terrificus venom: Immunochemical reactivity and experimental neutralizing capacity.

The venom of Crotalus durissus terrificus produces a neurotoxic and myotoxic syndrome that can lead to the death. Specific antivenom is the only treatment to neutralize the toxicity of the venom and the precocity in applying the antivenom is crucial for the efficiency of the treatment. We studied the variation of the immunochemical reactivity and neutralizing capacity of the specific antivenom on this venom in pre-incubation and rescue experiments, at different times. ELISA titers increased with longer venom-antivenom incubation times (p < 0.05) nevertheless incubation times had no effect on the neutralizing capacity of the antivenom. The antivenom dose necessary to rescue mice injected with 1.5 MMD (minimal mortal dose) 30 min after venom inoculation was over ten folds the dose of antivenom theoretically required to neutralize the same dose of venom according values obtained from pre-incubation experiments. Results showed that the in vitro immunochemical reactivity is not directly related to the neutralizing capacity. These observations underline the need for a rapid antivenom administration. Although preincubation experiments in mice are a powerful tool for the validation of the potency of the antivenoms in the productive process, it is clear that the nominal neutralization of the antivenoms must not be considered as a "stoichiometric" value regarding the venom to be neutralized in case of natural envenomation and emphasize the need of realization of clinical trials in order to evaluate the adequate doses of antivenom to be therapeutically used.

Accidentes y muertes por animales venenosos en Argentina durante el período 2000- 2011 / Accidents and deaths by venomous animals in Argentina during the period 2000-2011

En Argentina los accidentes causados por animales venenosos constituyen un problema de salud pública. En este estudio analizamos los accidentes y muertes por envenenamientos por mordedura o picadura de serpientes, escorpiones y arañas, y las muertes causadas por abejas- avispas-avispones, centípedos, animales marinos, otros artrópodos y otros animales venenosos en Argentina, recibidos por las autoridades sanitarias nacionales. Se analizó la información sobre accidentes y muertes producidas por este tipo de animales que fueron recibidas por el Ministerio de Salud de la Nación durante el período 2000-2011. Debido al tipo de sistema de notificación solo se pudieron calcular tasas de morbilidad y letalidad en los accidentes por arañas, escorpiones y serpientes. Contrariamente a lo que se suponía, no fueron estos los grupos que mayor cantidad de muertes causaron en el período de estudio, sino los himenópteros (abejas-avispas- avispones). El actual esquema de notificación de envenenamiento por animales venenosos provee información importante para el sistema sanitario. Sin embargo, deben realizarse modificaciones a fin de mejorar el conocimiento epidemiológico referente a envenenamientos por la mordedura o picadura de animales venenosos. De esta manera, se podrá progresar en la implementación de las medidas de prevención de estas patologías, su atención a nivel del primer nivel asistencial y la planificación de la producción de antivenenos.

In Argentina, accidents by venomous animals are a problem of public health. In this study we analyzed the envenomation caused by the bite or sting of snakes, scorpions and spiders and the deaths produced by the envenomation caused by this animals and the deaths caused by bees-wasp-hornet, centipedes, marine animals, other arthropods and other venomous animals in Argentina, recorded by the National Ministry of Health in the period 2000 ­ 2011. Most of the accidents were caused by scorpions nevertheless the highest lethality was observed in snakebites envenomation. Contrary to the general suppositions, hymenoptera (bee-wasp- hornet) were the responsible for the highest number of deaths. The present system of information of envenomation by venomous animals gives important information. However some modifications should be done to achieve a best knowledge of the epidemiological situation of the envenomation caused by bites or sting of the different venomous animals, in order to improve the prevention measures as well as the attention at the first level of sanitary assistance and the planning of antivenom production.

Toxicity of the venom of Latrodectus (Araneae: Theridiidae) spiders from different regions of Argentina and neutralization by therapeutic antivenoms.

"Black widow" spiders belong to the genus Latrodectus and are one of the few spiders in the world whose bite can cause severe envenomation in humans and domestic animals. In Argentina, these spiders are distributed throughout the country and are responsible for the highest number of bites by spiders of toxicological sanitary interest. Here, we studied the toxicity and some biochemical and immunochemical characteristics of eighteen venom samples from Latrodectus spiders from eight different provinces of Argentina, and the neutralization of some of these samples by two therapeutic antivenoms used in the country for the treatment of envenomation and by a anti-Latrodectus antivenom prepared against the venom of Latrodectus mactans from Mexico. We observed important toxicity in all the samples studied and a variation in the toxicity of samples, even in those from the same region and province and even in the same Latrodectus species from the same region. The therapeutic antivenoms efficiently neutralized all the venoms studied.

Lethality and histopathological alterations caused by Phoneutria nigriventer spider venom from Argentina: Neutralization of lethality by experimental and therapeutic antivenoms.

Although the spiders of the genus Phoneutria cause envenomation and their presence has been described in several provinces of the north of Argentina, they are not as common as other spiders of sanitary importance. In the present work, we studied the toxicity of samples of venom of Phoneutria spiders from the provinces of Misiones (where severe envenomation and deaths by Phoneutria have been recorded) and Jujuy (where no deaths have been recorded and severe envenomations are not frequent). To this end, we assessed the lethal potency in mice and guinea pigs and the histopathological alterations caused by both venoms, as well as the neutralization by the commonly used therapeutic antivenom produced by the Butantan Institute in Brazil and by an experimental antivenom developed with venom of P. nigriventer from Misiones. There were no differences in the lethality of the venoms of spiders from both regions. Post mortem examination showed that the heart and lungs were the most affected organs, while important pulmonary edema was seen macroscopically. Histological analysis showed edema, atelectasis, emphysema and cardiac lesion in both experimental models. The antivenoms assayed showed good neutralization of the venoms in the two experimental models. Despite the different geographic origins, the venoms showed similar toxicity and both the experimental antivenom and therapeutic antivenmos were able to neutralize the venoms of Argentinean P. nigriventer.

Venom yield and its relationship with body size and fang separation of pit vipers from Argentina.

The amount of venom that a snake can inject is related to its body size. The body size is related to head size and to the distance between fangs. To correlate snake body size, distance between fangs and distance between puncture wounds with the venom yield (and consequently with the venom dose potentially injected in a single snakebite), we studied these variables in two species of public health importance in South America, Bothrops (Rhinocerophis) alternatus, and Crotalus durissus terrificus. In all cases a positive correlation was observed between body length, fang separation distance, distance between puncture wounds and venom yield, with a regression coefficient over 0.5 for Bothrops alternatus and over 0.6 for Crotalus durissus terrificus in all cases, being the relation distance between punctures wounds and venom yield of 0.54 and 0.69 respectively. The difference between fang separation and puncture separation was never greater than 30%, with a mean difference around 13%. The strong relationships between body size, fang separation and venom yield may be useful for planning potential venom production in serpentariums. In addition, because puncture mark separation gives an approximate idea of the size of the snake, this provides a rough idea of the size of the snake that produced a bite and the potential amount of venom that could have been injected.