SciELO - Scientific Electronic Library Online

vol.49 número1Avaliação in vitro da atividade de seis drogas antimicrobianas contra Neisseria gonorrhoeaeAnnual review of immunology índice de autoresíndice de assuntospesquisa de artigos
Home Pagelista alfabética de periódicos  

Serviços Personalizados




Links relacionados


Revista do Instituto de Medicina Tropical de São Paulo

versão On-line ISSN 1678-9946

Rev. Inst. Med. trop. S. Paulo v.49 n.1 São Paulo jan./fev. 2007 



Acute neuromuscular manifestations in a patient associated with ingesting octopus (Octopus sp.)


Manifestações neuromusculares agudas associadas à ingestão de polvo comum Octopus sp.



Vidal Haddad JuniorI, II, III; Regina MouraI

IFaculdade de Medicina de Botucatu, Universidade Estadual Paulista, Botucatu, SP, Brasil
IIPrograma de Pós-Graduação em Zoologia, Instituto de Biociências de Botucatu, Universidade Estadual Paulista, Botucatu, SP, Brasil
IIIHospital Vital Brazil, Instituto Butantan, São Paulo, SP, Brasil

Correspondence to




The authors report neuromuscular manifestations in a 45-year-old woman after consuming octopus meat (Octopus sp.). The patient presented malaise, paresthesias in perioral and extremity areas, intense muscular weakness and arterial hypotension, followed by severe itch and disseminated cutaneous rash. Gastrointestinal manifestations and fever were not observed, reducing the probability of alimentary poisoning. The presence of muscular and neurological symptoms suggests neurotoxin action, which could have been ingested by the victim from the octopus salivary glands or from an accumulation of toxins in the meat, or by an unknown mechanism. There is little known about toxins of the Octopus genus and this communication is important alert to the possibility of poisoning in humans that eat octopus and its differentiation from alimentary poisonings arising from incorrect conservation of seafood.

Keywords: Aquatic poisonous animals; Brazil; Octopus sp.; Octopuses; Poisoning, Venomous and poisonous marine animals.


Os autores relatam um quadro manifestado por sintomas neurológicos e musculares em uma mulher de 45 anos, que surgiu após o consumo da carne de polvo comum (Octopus sp.). A paciente apresentou intenso mal estar, parestesias em extremidades e área perioral, fraqueza muscular intensa e hipotensão arterial, seguidos de prurido importante e uma erupção eritêmato-descamativa disseminada tardia. Não foram observadas manifestações gastrintestinais ou febre, o que reduziu a probabilidade de uma intoxicação alimentar por conservação inadequada do molusco. A presença de sintomas neuro-musculares é sugestiva de ação de neurotoxinas, comprovadamente existentes em muitos gêneros de polvos e que podem ter sido ingeridas através do consumo das glândulas salivares ou acúmulo das toxinas na carne, por algum mecanismo ainda desconhecido. As toxinas dos polvos do gênero Octopus são pouco estudadas e julgamos esta comunicação importante por alertar para a possibilidade do envenenamento nos seres humanos que consomem carne de polvos e ainda sua diferenciação das intoxicações alimentares que ocorrem por conservação inadequada do animal.




There are over 50,000 known species in the Phylum Mollusca. In general, mollusks have a head (with sense organs and a "brain"), a viscera mass, and a muscular foot-like structure, which is in contact with the substrate9.

Venomous animals are capable of inoculating venom to capture prey or defend themselves against predators, using their own apparatus. Poisonous animals can poison predators passively through toxins produced or stored in their bodies1,3. There are poisonous and venomous mollusks. Some diseases from toxins can be caused by consuming poisonous clams and mussels, such as shellfish poisoning caused by a potent neurotoxin, saxitoxin, produced by dinoflagellates.

The most important venomous mollusks are from the Gastropoda and Cephalopoda classes. Gastropoda of the genus Conus contain mollusks able to envenom prey and occasionally even Man.

The Cephalopoda class contains squid, octopuses, cuttlefish, and nautiluses which are widely distributed throughout tropical and temperate seas. Octopuses vary in size from a few centimeters to the giant octopus of the Pacific Ocean which can grow to over 10 m, but Brazilian octopuses rarely exceed 1 m. They have "feet" (mistakenly called tentacles) and a horny "beak" used to capture prey, especially other mollusks (bivalves), but they also feed on Crustacea and fish. Octopuses have defense mechanisms that eject jets of water that move their bodies quickly in the opposite direction and they eject a cloud of dark ink that confuses predators. A third defense and attack mechanism exists; this is toxins found in the salivary glands, which are linked to their mandible or beak.

The blue-ringed octopus (Hapalochlaena maculata and Hapalochlaena lunulata) inoculates maculotoxin from their saliva glands through their horny beak (it was recently demonstrated that maculotoxin is identical to tetrodotoxin)10. Tetrodotoxin is a potent neurotoxin that blocks axonal sodium channels and provokes a muscular paralysis similar to that observed in accidents with Conus shells, including fatal respiratory arrest2,11,12. In accidents caused by the blue-ringed octopus, initial pain is not so intense. The blue-ringed octopus is not found in the Atlantic Ocean.

It should be pointed out that there are enzymes to facilitate digestion and toxins to immobilize prey in the saliva glands of all octopuses, even those along the Brazilian coast. There are five species of octopuses recorded along the Northeast Coast of Brazil: Octopus macropus, Octopus defilippi, Octopus sp. C., Octopus cf vulgaris, and Octopus filosus, the first three are cosmopolitan and Octopus filosus is restricted to the Caribbean and the North and Northeast of Brazil. Octopus cf vulgaris is the most common octopus around the Brazilian and South American coast and does not present morphological differences with specimens from South and Southeast coast of Brazil6,8. Recent reports have pointed to the presence of cephalotoxin, a glycoprotein, in the saliva of some octopus species, including the Octopus macropus and Octopus vulgaris7. These probable neurotoxins cause paralysis in crustaceans but there are no reported studies on their effect in mammals.

Reports of poisoning caused by ingesting cephalopods are rare with only one report of a series of poisoning outbreaks after ingestion of cephalopod meat in Japan5. The predominant symptoms were fever, diarrhea, abdominal pain, weakness, dehydration, and convulsions. The total number of patients observed was 758 and almost all presented gastrointestinal symptoms, but three developed convulsions and three presented muscular paralysis4.



A 45-year-old white female physician presented at our service for evaluation of intense itching and a general erythematous rash appearing after ingestion of octopus meat.

While on vacation in a northeast Brazilian coastal city she ate two helpings of semi-raw octopus meat. Some hours after the meal she felt a sensation of tingling in her face, mainly around the lips, followed by a similar sensation in the legs and arms and a sensation of illness followed by vertigo and arterial hypotension (70 x 40 mm Hg). She felt her radial pulse was weak, a cold sensation, and intense weakness in her extremities. She did not present fever or gastrointestinal manifestations but reported feeling dehydrated although she had ingested substantial liquid. She did not eat anything else but only drank carbohydrate-electrolyte drinks and water. This sensation persisted for some hours into the night, so she decided to use antihistamines (dexchlorpheniramine, 2 mg po). The following morning most of the manifestations had disappeared but vertigo remained. About 48 hours later an intense itch appeared in the superior members, followed by erythema in the trunk and a generalized erythematous rash when she presented for dermatological examination. The manifestations disappeared after five days. In a follow-up contact with the hotel, they sent us images of the octopus used in their cookery (Fig. 1 and 2); this was classified as the Octopus genus (Octopus sp.).






Most accidents caused by octopuses are traumatic and are from the mandible or beak, causing lacerations and bleedings. A small percentage show envenoming associated with salivary gland toxin inoculation via the beak. Poisoning is very rare and is seen after ingestion of mollusk meat.

The symptoms presented by this patient are compatible with neurotoxicity, especially perioral tingling, muscular weakness, and systemic hypotension. It is important to note the absence of fever and gastrointestinal manifestations, which practically eliminates the probability of poisoning from badly conserved octopus meat and shows a different profile to poisonings observed by KAWABATA et al. (1957), which mainly displayed gastrointestinal symptoms. It is very possible that the patient was poisoned by octopus toxins, but it is not possible to confirm whether the patient's manifestations resulted from ingesting toxins from the saliva glands of semi-raw octopus or from other toxins present in the actual meat of the animal, but the now widespread habit of eat raw fish and seafood in Japanese cooking can contribute to some poisonings.



Neurotoxins from the salivary glands can remain active in the presence of high temperatures, which could also have contributed to the poisoning. Despite octopuses of the Octopus genus having neurotoxins to paralyze their food, there are few reports on their action and the information that does exist was not sufficient for the evolution and prognosis of the accident, which seemed less serious than those caused by the blue ringed octopus. However, there is a need for more studies on their action.

The diagnosis of poisonings caused by venomous mollusks is based on clinical observation. There is no antidote to the toxins and severe envenomation or poisoning should be treated with artificial ventilation, the only effective measure, as there is no antivenom available10. Gravity depends on the time elapsed since envenomation or poisoning and the full appearance of the manifestations, as well as considering where the accident occurred, as lack of medical resources also influences prognosis. This report of an accident producing neuromuscular blockade symptoms in a patient after consuming octopus meat must alert us to the possibility of poisoning from consumption of these common mollusks, which must not be confused with food poisoning.



1. CARDOSO, J.L.C.; FRANÇA, F.O.S.; WEN, F.H.; MALAQUE, C.M.S. & HADDAD Jr., V. - Animais peçonhentos no Brasil: Biologia, clínica e terapêutica dos acidentes. São Paulo, Sarvier, 2003. p. 264-278.         [ Links ]

2. FLECKER, H. & COTTON, B.C. - Fatal bite from an octopus. Med. J. Aust., 2: 329-331, 1955.         [ Links ]

3. HADDAD Jr., V. - Atlas de animais aquáticos perigosos do Brasil: guia médico de identificação e tratamento (Atlas of dangerous aquatic animals of Brazil: a medical guide to identification and treatment). São Paulo, Roca, 2000. p. 28-35.         [ Links ]

4. HALSTEAD, B.W. - Poisonous and venomous marine animals of the world. Princeton, Darwin, 1988. p. 296-328.         [ Links ]

5. KAWABATA, T.; HALSTEAD, B.W. & JUDEFIND, T.F. - A report of a series of recent outbreaks of unusual cephalopod and fish intoxications in Japan. Amer. J. trop. Med. Hyg., 6: 935-939, 1957.         [ Links ]

6. LEITE, T.S. - Caracterização da fauna de polvos (Cephalopoda: Família Octopodidae) de águas rasas do litoral e de ilhas oceânicas do Nordeste Brasileiro. Rio Grande do Sul, 2002. (Dissertação de Mestrado - Fundação Universidade do Rio Grande).         [ Links ]

7. MEBS, D. - Venomous and poisonous animals: a handbook for biologists, toxicologists and toxinologists, physicians and pharmacists. Boca Raton, CRC Press, 2002. p. 71-75.         [ Links ]

8. ROPER, C.F.E.; SWEENEY, M.J. & NAUEN, C.E. - Cephalopods of the world. Rome, Food and Agriculture Organization, 1984.         [ Links ]

9. RUPPERT, E.; FOX, E.R.S. & BARNES, R.D. - Invertebrate Zoology, a functional evolutionary approach. 7. ed. Belmont, Brooks/Cole-Thomson Learning, 2003. p. 414-422.         [ Links ]

10. SHEUMACK, D.D.; HOWDEN, M.E.H.; SPENCE, I. & QUINN, R.J. - Maculotoxin: a neurotoxin from the venom glands of the octopus Hapalochlaena maculosa identified a tetrodotoxin. Science, 199: 188-189, 1978.         [ Links ]

11. SUTHERLAND, S.K. & LANE, W.R. - Toxins and mode of envenomation of the common ringed or blue-banded octopus. Med. J. Aust., 1: 893-898, 1969.         [ Links ]

12. WALKER, D.G. - Survival after severe envenomation by the blue-ringed octopus (Hapalochlaena maculosa). Med. J. Aust., 2: 663-665, 1983.         [ Links ]



Correspondence to:
Vidal Haddad Junior
Caixa Postal 557
18618-000 Botucatu, SP, Brasil

Received: 26 January 2006
Accepted: 17 July 2006

Creative Commons License Todo o conteúdo deste periódico, exceto onde está identificado, está licenciado sob uma Licença Creative Commons