Life-threatening episode after ingestion of toad eggs: a case report with literature review

It is known that toad possesses several toxic substances in the skin and parotid glands. In the past, toad-venom poisoning had been reported from ingestion of toad soup, Kyushin and aphrodisiac pills, but the poisoning from toad eggs is observed for the first time. The case of a healthy female who had previously eaten toad soup twice without any discomfort is reported. She developed gastrointestinal symptoms and life-threatening cardiac rhythm after ingestion of toad eggs.

Toad venom poisoning: resemblance to digoxin toxicity and therapeutic implications

A healthy man developed gastrointestinal symptoms after ingesting purported aphrodisiac pills. He had severe unrelenting bradycardia, hyperkalaemia, and acidosis. He rapidly developed severe life threatening cardiac arrhythmias and died after a few hours. He was found to have positive serum digoxin concentrations, although he was not taking digoxin. Toad venom poisoning is similar to digitalis toxicity and carries a high mortality. Cardiac glycoside poisoning can occur from ingestion of various plants and animal toxins, and the venom gland of cane toad (Bufo marinus) contains large quantities of cardiac glycosides. Toad venom, a constituent of an aphrodisiac, was considered responsible for the development of clinical manifestations and death in this patient. Digoxin specific Fab fragment has been reported to be beneficial in the treatment of toad venom poisoning. This report alerts physicians to the need to be aware of a new community toxic exposure, as prompt treatment with digoxin specific Fab fragment may be life saving. The treatment approach to patients with suspected toad venom poisoning is described.

Efficacy of digoxin specific Fab fragments (Digibind) in the treatment of toad venom poisoning

Chan Su, a traditional Chinese medication, and Love Stone, a topical aphrodisiac, are both made from dried venom of the toad bufo bufo gargarizans and contain bufalin, cinobufotalin, cinobufagin, and other cardioactive steroids of the bufadienolide class. Deaths have occurred following ingestion of these products and the clinical course resembles digoxin toxicity. The purpose of this study was to determine the efficacy of digoxin specific Fab fragments in treating Chan Su poisoning. An ethanolic extract was prepared from Chan Su. Digoxin specific Fab fragments were reconstituted in normal saline to a concentration of 80 mg/ml. An approximate LD90 dose was determined in preliminary experiments. Mice were then randomly divided into a treatment group of 15 mice and a control group of 30 mice. The treatment group was pretreated with 20 ml/kg of digoxin specific Fab fragment solution by intraperitoneal injection at t = 0, followed by 10 ml/kg of digoxin specific Fab fragments intraperitoneal at t = 30 min. The control group was pretreated with equal volumes of intraperitoneal normal saline at the same times. Immediately following the 30 min injection, both groups were given the estimated LD90 dose of Chan Su extract by subcutaneous injection. An endpoint of survival at 6 h was chosen after preliminary results showed that all deaths occurred in the first 4 h. All 30 of the control mice had seizures followed by death compared to 11 seizures and 7deaths in the 15 treatment mice. These results were statistically significant by Fisher's exact test (p = 0.00003 for mortality and p = 0.009 for seizures). Digoxin specific Fab fragments are effective in the treatment of Chan Su poisoning in mice and may be effective for poisoning by other cardioactive steroids of the bufadienolide class.

Prognostic implications of hyperkalemia in toad toxin intoxication

The toad possesses several toxic substances. Toad toxin poisoning manifests itself primarily with digitalis-like, cardioactive effects which results in bradycardia, varying degrees of atrio-ventricular block, ventricular tachycardia, ventricular fibrillation and sudden death. We report a cluster poisoning in a family who became intoxicated after ingestion of cooked toad soup for a skin problem. The youngest one (15 months old) died of refractory bradydyarrhythmias soon after arriving at our hospital. A second child (20 months old), who survived, arrived in shock with hyperkalemia (potassium 7.3 mEq/ L) and varying degrees of atrio-ventricular block. She was successfully treated with atropine, lidocaine, and cardioversion, and had a transvenous temporary pacemaker implanted for 1 day. The third boy (16 years old) had hyperkalemia (potassium 6.3 mEq/L) and bradycardia. The remaining three adults had only mild symptoms of nausea, vomiting, watery diarrhea and a sensation of numbness over their oral mucosa. We found that the level of serum potassium had prognostic implications in toad intoxication. Determination of serum potassium level is readily available in almost every hospital and is therefore more convenient to measure than serum digoxin level. We conclude that if hyperkalemia develops, the treatment of toad intoxication must be more aggressive to prevent mortality.

Treatment of toad venom poisoning with digoxin-specific Fab fragments

Toxicity from toad venom poisoning is similar to digoxin toxicity and carries a high mortality rate. We report on six previously healthy men who developed vomiting and bradycardia after ingesting a purported topical aphrodisiac. Each patient had positive apparent digoxin levels and the first four patients died of cardiac dysrhythmias. The last two patients recovered following treatment with digoxin Fab fragments. We analyzed samples of the purported aphrodisiac and found that it was identical to Chan Su, a Chinese medication made from toad venom. To our knowledge, this is the first reported use of digoxin Fab fragments to treat toad venom poisoning.

[Toad or toad cake intoxication in Taiwan: report of four cases]

The parotid glands and skin of the toad contain toxic substances. Ingestion of toad or toad cake may result in intoxication. Clinically, it may be predominantly manifested by a digitalis-like cardioactive effect. During the last six years, the National Poison Center of Taiwan has collected four cases of toad or toad cake intoxication: two cases were toad intoxication and two cases were toad cake intoxication. All four cases manifested with general weakness; three cases showed bradycardia, vomiting and diarrhea; two cases had numbness of the oral cavity; one case had excessive salivation; and two cases showed a consciousness change. In one case, an EKG showed bradycardia, and a first and second degree A-V block; this patient died of ventricular fibrillation. The prognosis in two cases was good. We lost contact with the last patient. The treatment principles in toad or toad cake intoxication is life support. If ingested, treatment is directed at prevention of absorption, including emesis, gastric lavage, activated charcoal and cathartics. Atropine, a pacemaker and other antiarrhythmic agents may be helpful in treating cardiovascular toxicity.

A digoxin-like immunoreactive substance and atrioventricular block induced by a Chinese medicine "kyushin"

The attempted suicide by 2 women with a kyushin overdose is reported. Kyushin caused them to produce a significant elevation of a serum digoxin-like immunoreactive substance (2.35 and 1.84 ng/ml) and symptoms of nausea, vomiting and general malaise. Their blood biochemistry and electrolytes were normal. In one patient, an electrocardiogram revealed a second degree Wenckebach atrioventricular block and T-wave change. Toad venom, a kyushin ingredient, is possibly responsible for the development of these clinical features and electrocardiographic changes.

Naturally occurring cardiac glycosides

Cardiac glycoside poisoning from the ingestion of plants, particularly of oleanders, occurs with reasonable frequency in tropical and subtropical areas. We have assessed a variety of plant specimens for their cardiac glycoside content by means of radioimmunoassays with antibodies that differ in their specificity for cardiac glycosides. Significant amounts of immunoreactive cardiac glycoside were found to be present in the ornamental shrubs: yellow oleander (Thevetia peruviana); oleander (Nerium oleander); wintersweet (Carissa spectabilis); bushman's poison (Carissa acokanthera); sea-mango (Cerbera manghas); and frangipani (Plumeria rubra); and in the milkweeds: redheaded cotton-bush (Asclepias curassavica); balloon cotton (Asclepias fruiticosa); king's crown (Calotropis procera); and rubber vine (Cryptostegia grandifolia). The venom gland of the cane toad (Bufo marinus) also contained large quantities of cardiac glycosides. The competitive immunoassay method permits the rapid screening of specimens that are suspected to contain cardiac glycosides. Awareness of the existence of these plant and animal toxins and their dangers allows them to be avoided and poisoning prevented. The method is also useful for the confirmation of the presence of cardiac glycosides in serum in cases of poisoning.