A diver's guide to subaquatic envenomation in the Mediterranean.

INTRODUCTION: Between 40,000 and 50,000 divers and swimmers are envenomated each year and diving as a hobby is becoming increasingly popular. In the Mediterranean, envenomation is most often by Weever fish, Scorpion fish and jellyfish but coral and sea urchins may also be venomous. ENVENOMATION: Most stings cause local inflammation, oedema and pain. The severity of pain varies with the venom and the amount injected. In severe cases, stings may be life-threatening due to cardiogenic or anaphylactic shock or penetration of vital structures. MANAGEMENT: Most cases of envenomation are preventable with a combination of measures including the avoidance of contact through good buoyancy control, the wearing of body-suits, and by maintaining visual awareness. Immediate management is to return to the surface, elevate and wash the site of injury. Immersion in hot water followed by simple analgesics for pain relief has been shown to be more effective than other methods. More severe cases should be identified by symptoms including confusion and heavy bleeding and referred to qualified medical care. CONCLUSION: Envenomation by subaquatic species is common and preventable yet the dissemination of the appropriate knowledge is limited. This knowledge summary provides pertinent information aimed at divers in preventing and managing such injuries.

Is hot water immersion an effective treatment for marine envenomation?

Envenomation by marine creatures is common. As more people dive and snorkel for leisure, the incidence of envenomation injuries presenting to emergency departments has increased. Although most serious envenomations occur in the temperate or tropical waters of the Indo-Pacific region, North American and European waters also provide a habitat for many stinging creatures. Marine envenomations can be classified as either surface stings or puncture wounds. Antivenom is available for a limited number of specific marine creatures. Various other treatments such as vinegar, fig juice, boiled cactus, heated stones, hot urine, hot water, and ice have been proposed, although many have little scientific basis. The use of heat therapies, previously reserved for penetrating fish spine injuries, has been suggested as treatment for an increasing variety of marine envenomation. This paper reviews the evidence for the effectiveness of hot water immersion (HWI) and other heat therapies in the management of patients presenting with pain due to marine envenomation.

Guidance values for microcystins in water and cyanobacterial supplement products (blue-green algal supplements): a reasonable or misguided approach?

This article reviews current scientific knowledge on the toxicity and carcinogenicity of microcystins and compares this to the guidance values proposed for microcystins in water by the World Health Organization, and for blue-green algal food supplements by the Oregon State Department of Health. The basis of the risk assessment underlying these guidance values is viewed as being critical due to overt deficiencies in the data used for its generation: (i) use of one microcystin congener only (microcystin-LR), while the other presently known nearly 80 congeners are largely disregarded, (ii) new knowledge regarding potential neuro and renal toxicity of microcystins in humans and (iii) the inadequacies of assessing realistic microcystin exposures in humans and especially in children via blue-green algal food supplements. In reiterating the state-of-the-art toxicology database on microcystins and in the light of new data on the high degree of toxin contamination of algal food supplements, this review clearly demonstrates the need for improved kinetic data of microcystins in humans and for discussion concerning uncertainty factors, which may result in a lowering of the present guidance values and an increased routine control of water bodies and food supplements for toxin contamination. Similar to the approach taken previously by authorities for dioxin or PCB risk assessment, the use of a toxin equivalent approach to the risk assessment of microcystins is proposed.

Poisoning, envenomation, and trauma from marine creatures.

In the course of their clinical work or during leisure activity, family physicians occasionally may encounter patients with injuries from marine creatures. Poisoning, envenomation, and direct trauma are all possible in the marine environment. Ciguatera poisoning can result from ingestion of predatory fish that have accumulated biotoxins. Symptoms can be gastrointestinal or neurologic, or mixed. Management is mostly symptomatic. Scombroid poisoning results from ingestion of fish in which histamine-like substances have developed because of improper refrigeration. Gastrointestinal and systemic symptoms occur. Treatment is based on antihistamines. Envenomations from jellyfish in U.S. waters and the Caribbean are painful but rarely deadly. Household vinegar deactivates the nematocysts, and manual removal of tentacles is important. Treatment is symptomatic. Heat immersion may help with the pain. Stingrays cause localized damage and a typically severe envenomation. The venom is deactivated by heat. The stingray spine, including the venom gland, typically is difficult to remove from the victim, and radiographs may be necessary to localize the spine or fragment. Surgical débridement occasionally is needed. Direct trauma can result from contact with marine creatures. Hemorrhage and tissue damage occasionally are severe. Infections with organisms unique to the marine environment are possible; antibiotic choices are based on location and type of injury. Shark attacks, although rare, require immediate attention.

Seasonality of diarrhetic shellfish poisoning at a coastal lagoon in Portugal: rainfall patterns and folk wisdom.

Of the three types of toxicity known so far in Portuguese shellfish, only diarrhetic shellfish poisoning (DSP) and amnesic shellfish poisoning (ASP) are produced by microalgae that seem to have been present in the last decades or centuries. The most important paralytic shellfish poisoning (PSP) producer, Gymnodinium catenatum, is hypothesised to have been introduced quite recently as only in 1976 PSP toxicity was detected for the first time in shellfish from Galicia, NW Iberian Peninsula. While ASP presents very short episodes of contamination, the concentration of DSP toxins in some years surpasses human safety values for much longer periods. It is traditionally stated that shellfish should be consumed in 'months with R' (September-April). A retrospective study of the maximum monthly DSP levels attained in mussels from a coastal lagoon-Ria de Aveiro-between 1994 and 2001, showed that the highest frequency of months with concentrations surpassing the safety level of 2 microg/g digestive glands were found in June-September, followed by May and October. These months correspond with the months of lowest historical average rainfall in the period 1941-1998. Oscillations in the rainfall pattern coincided with earliest (or latest) detection by HPLC of DSP toxins in mussel in the years studied. In a semi-closed lagunar environment prone to in situ growth of DSP-producer microalgae, like Dinophysis acuminata, rainfall affects river output, lowering salinity and disrupting water column stability that favours Dinophysis growth. The seasonality of DSP recurrence may be connected to the folk adage on safety of shellfish consumption, after many years of empirical observations by coastal populations of diarrhoea episodes in summertime.

Venomous marine creatures.

BACKGROUND: Many venomous marine creatures inhabit Australian waters, causing significant morbidity and occasional fatalities. No antivenom is available for most of these creatures. Little is known about the venom or syndromes produced by many of these creatures. OBJECTIVE: This article discusses the features of envenomation by some of the more commonly encountered venomous marine creatures, and the recommended first aid and medical management of such envenomations. DISCUSSION: The information contained within this article is intended to provide the reader with an overview of some of the more common marine envenomations, and hopefully with the knowledge to effectively manage such problems.

Acute renal failure associated with freshwater fish toxin.

Clinical observations on toxicity after ingestion of gall bladder of Labeo rohita, a freshwater fish found commonly in India, were recorded from 22 patients between 1985 to 1990. The gall bladder in raw, cooked or desiccated form was swallowed as a traditional method of treatment for various chronic diseases. Patients generally presented with gastrointestinal symptoms such as cramping pain, nausea and vomiting within 12 hours (mean 4.6 +/- 3.7 hours) after ingestion. Subsequently renal failure was observed in all and hepatic dysfunction in some (36.3%) patients. The outcome in general is good. From the clinical course the role of toxic substance(s) is presumed as the causative factor(s), which needs further evaluation.

Treatment of ciguatera fish poisoning with amitriptyline and nifedipine.

Ciguatera fish poisoning is the most common fish poisoning in the United States. Symptoms involve the gastrointestinal, cardiovascular and neurological systems. No known treatment exists. We explore the therapeutic effect of amitriptyline in two patients and nifedipine in one patient. Amitriptyline demonstrated resolution of most symptoms except for heat/cold reversal in one patient and heat/cold reversal, pruritus and headache in the second patient. We then used nifedipine in the second patient and noted only the resolution of his headaches. We recommend further study of these agents for the treatment of ciguatera fish poisoning.