Numerous reports in the literature describe cases of fish poisoning occurring due to ingestion of several species, some of the most important being:

• Shellfish - Poisoning from this fish stems from the effects of saxitoxin, a compound found in butter clams, geoducks, mussels, and other bivalve mollusks that are eaten by shellfish [1] [2] [3]. It is a very potent molecule capable of producing symptoms within several hours after being introduced into the gastrointestinal tract [2] [3]. Because saxitoxin blocks voltage-gated sodium channels, neurological symptoms are a constitutive feature of this type of fish poisoning; circumoral paresthesia, numbness and a tingling sensation of the extremities, ataxia, weakness, and altered consciousness are principal findings [2] [3]. In severe cases, hypertension and tachycardia may be accompanied by a severe muscular and respiratory paralysis, thus the term paralytic shellfish poisoning is often used [2] [3]. In rare cases, the effects of another toxin found in shellfish (brevetoxin) can cause temperature-related dysesthesia [1].
• Pufferfish - Ingestion of pufferfish is a potentially life-threatening clinical entity and is known as fugu poisoning. Tetrodotoxin (TTX), similarly to saxitoxin, impairs the transmission of neuromuscular impulses [4] [5]. Lightheadedness, weakness, vomiting, and a rapidly ascending paralysis, eventually affecting respiratory muscles, may be fatal within 6-24 hours [5]. Diaphoresis, excessive salivation, dysphagia, convulsions, hypotension, bradycardia, and fixed dilated pupils are other notable symptoms of pufferfish poisoning [4] [5].
• Scombroid species - Initially described from tuna, mackerel, and other fish belonging to the Scombridae family, and later with sardines and anchovies, scombroid fish poisoning arises in the setting of improper storage or processing, resulting in the accumulation of histamine [6] [7]. Thus, typical symptoms resemble an acute allergic reaction - disseminated erythema (without wheals) and flushing are accompanied by abdominal cramping, diarrhea, and vomiting [6] [7]. Headaches, palpitation, and dizziness are frequently reported [7]. Furthermore, bronchospasm and respiratory distress in conjunction with an unstable blood pressure can appear as well [6]. Symptoms develop shortly after consuming the fish (in the first hour and a half) and resolve within 36 hours [6].
• Reef fish - Ciguatera fish poisoning (CFP), named after ciguatoxins that produce gastrointestinal (vomiting, diarrhea, abdominal pain), neurologic (paresthesias, pruritis), and musculoskeletal (myalgia, arthralgia, and weakness) symptoms in a period of hours, is primarily seen after consumption of fish species residing in coral reefs [1]. Dysesthesia is a constitutive feature of ciguatera fish poisoning as well, and it may be confused with shellfish poisoning [1].

• Vomiting

  Lightheadedness, weakness, vomiting, and a rapidly ascending paralysis, eventually affecting respiratory muscles, may be fatal within 6-24 hours. [symptoma.com]

  Do not induce vomiting or give syrup of Ipecac. Ipecac was formerly used to induce vomiting in poisoned patients where there was a chance to get the toxin out of the body. [medicinenet.com]

  After eating contaminated clams or mussels, you will most likely experience nausea, vomiting, and diarrhea. [medlineplus.gov]

  The diagnosis usually is made by the presence of gastrointestinal symptoms, nausea, vomiting, and diarrhea, and of neurological symptoms such as paresthesias, paresis, and pruritus. [ncbi.nlm.nih.gov]

  Abdominal cramps, nausea, vomiting, and diarrhea last 6 to 17 h; then, pruritus, paresthesias, headache, myalgia, reversal of hot and cold sensation, and face pain may occur. [merckmanuals.com]

• Nausea

  Symptoms of poisoning may include paralysis, respiratory failure, numbness, paraesthesia, nausea and ataxia. Health professionals should be aware of the condition so as to institute early and appropriate management. [ncbi.nlm.nih.gov]

  Abdominal cramps, nausea, vomiting, and diarrhea last 6 to 17 h; then, pruritus, paresthesias, headache, myalgia, reversal of hot and cold sensation, and face pain may occur. [merckmanuals.com]

  Symptoms include: nausea, vomiting, diarrhea, muscle pain, numbness, tingling, abdominal pain, dizziness, and vertigo. Hot and cold sensation may be reversed. [medicinenet.com]

• Food Poisoning

  Causes of fish food poisoning This type of food poisoning is caused by fish which has been contaminated by: Parasites Toxins Bacteria, e.g. [medic8.com]

  What Is the Most Common Way to Get Food Poisoning From Fish? There are actually two ways in which you can get food poisoning from consuming fish. [healthguidance.org]

  Food poisoning can occur if raw fish gets too warm before it is served. (Image: merc67/iStock/Getty Images) Different types of food poisoning can occur from the consumption of raw fish. One of the most common is referred to as Scromboid poisoning. [livestrong.com]

  The treatment of this food poisoning is supportive, although intravenous mannitol is reported to be safe and effective. The prognosis is good and complete recovery is to be expected. [ncbi.nlm.nih.gov]

  Ciguatera fish poisoning Ciguatera poisoning is a form of food poisoning caused by eating warm water ocean fish that have ciguatera poison (toxin). [sahealth.sa.gov.au]

• Abdominal Pain

  OBJECTIVE: We describe the case of a young man who suffered from diarrhea and abdominal pain after eating raw fish and who also developed severe ataxia with spontaneous downbeat and perverted head-shaking nystagmus. [ncbi.nlm.nih.gov]

  In addition, individuals may experience burning or swelling of the mouth, abdominal pain, or a metallic taste. Most people experience mild symptoms which should resolve on their own within 12 hours. [bouldercounty.org]

• Epigastric Pain

  Facial flushing and possibly nausea, vomiting, epigastric pain, and urticaria occur within a few minutes of eating and resolve within 24 h. Symptoms are often mistaken for those of a seafood allergy. [merckmanuals.com]

• Impulsivity

  Tetrodotoxin (TTX), similarly to saxitoxin, impairs the transmission of neuromuscular impulses. Lightheadedness, weakness, vomiting, and a rapidly ascending paralysis, eventually affecting respiratory muscles, may be fatal within 6-24 hours. [symptoma.com]

• Headache

  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. [ncbi.nlm.nih.gov]

  Signs and symptoms Symptoms include: tingling and burning around the mouth facial flushing and sweating nausea, vomiting and diarrhoea headache palpitations and dizziness rash. [sahealth.sa.gov.au]

  Symptoms may include: Nausea Vomiting Watery diarrhea Headache Numbness and tingling about the mouth and extremities In more severe cases, the person may suffer muscle pains, dizziness, and sensations of temperature reversal, where hot things seem cold [hopkinsmedicine.org]

• Nystagmus

  OBJECTIVE: We describe the case of a young man who suffered from diarrhea and abdominal pain after eating raw fish and who also developed severe ataxia with spontaneous downbeat and perverted head-shaking nystagmus. [ncbi.nlm.nih.gov]

Because of the rapid onset of symptoms seen in the mentioned types of fish poisoning, a prompt diagnosis can be life-saving. A proper patient history is the single most important step in the workup. Data regarding recent consumption of fish, the development of similar symptoms in friends or other persons who ate the same food (or have been in the same restaurant) can be crucial for a presumptive diagnosis of intoxication [1] [5] [7]. The physical examination is an important component of the workup, during which the severity of complaints and their progression should be defined, mainly in order to consider the optimal therapeutic approach. Despite the scarce availability of commercial tests for specific toxins found in fish, recent introduction of novel biochemical tests might be useful for detecting the concentration of ciguatera toxin, histamine, tetrodotoxin, and saxitoxin in respective fish species; this confirming the presumed source [1] [2] [3] [5] [6]. An assessment of histamine concentration in blood or its metabolites in urine might also be a useful diagnostic tool [6].

• Slow Nerve Conduction Velocity

  However, intraperitoneal injection of ciguatoxin in rats increases neuronal refractory period and slows nerve conduction velocity. Treatment with mannitol fails to correct these effects. [ncbi.nlm.nih.gov]

Treatment with mannitol fails to correct these effects. [ncbi.nlm.nih.gov]

The prognosis is good and complete recovery is to be expected. However, relapses can occur, especially on re-exposure to the toxin. [ncbi.nlm.nih.gov]

Prognosis The prognosis for PSP is quite good, especially if the patient has passed the initial 12 hours of illness without needing breathing support. Most deaths occur during this period if breathing help is not available. [medical-dictionary.thefreedictionary.com]

During 2009-2015, 85 outbreaks of confirmed histamine fish poisoning involving 250 illnesses were reported to the CDC, with one hospitalizaiton and no deaths. [14] Prognosis Patients with histamine fish toxicity have a good prognosis. [emedicine.medscape.com]

Other postulated second agents are cadaverine or putrescine. [9, 10] Etiology The fish species most commonly implicated in histamine toxicity are scombroid dark-meat fish (eg, tuna, mackerel, skipjack, bonito, marlin) and nonscombroid species, such as [emedicine.medscape.com]

In this review, we discuss the epidemiology, pathophysiology, evaluation, and treatment of scombroid disease. [ncbi.nlm.nih.gov]

PURPOSE: The purpose of this study was to investigate the pathophysiology of persistent orthostatic hypotension in a patient with ciguatera fish poisoning. [ncbi.nlm.nih.gov]

This paper is a general review of CFP including the human health effects of exposure to ciguatoxins (CTXs), diagnosis, human pathophysiology of CFP, treatment, detection of CTXs in fish, epidemiology of the illness, global dimensions, prevention, future [mdpi.com]

Prevention Refrigerate seafood at less than 38°F (3.3°C) to prevent it from spoiling. Don't eat fish that you think may be spoiled or poorly refrigerated. Don't eat fish if it has an unusual peppery bitter taste. [fairview.org]

Prevention Fish should be chilled and properly refrigerated as soon as possible after being caught to prevent histamine formation. [sahealth.sa.gov.au]

To prevent mass poisoning in gatherings and parties, the most ciguatoxic fish species and potentially toxic fish species must be avoided. [ncbi.nlm.nih.gov]

1. Friedman MA, Fleming LE, Fernandez M, et al. Ciguatera Fish Poisoning: Treatment, Prevention and Management. Mar Drugs. 2008;6(3):456-479.
2. Hurley W, Wolterstorff C, MacDonald R, Schultz D. Paralytic Shellfish Poisoning: A Case Series. West J Emerg Med. 2014;15(4):378-381.
3. Centers for Disease Control and Prevention (CDC). Paralytic shellfish poisoning - Southeast Alaska, May-June 2011. MMWR Morb Mortal Wkly Rep. 2011;60(45):1554–1556.
4. Lago J, Rodríguez LP, Blanco L, Vieites JM, Cabado AG. Tetrodotoxin, an Extremely Potent Marine Neurotoxin: Distribution, Toxicity, Origin and Therapeutical Uses. Long P, ed. Mar Drugs. 2015;13(10):6384-6406.
5. Centers for Disease Control and Prevention (CDC). Tetrodotoxin poisoning associated with eating puffer fish transported from Japan--California, 1996. MMWR Morb Mortal Wkly Rep. 1996;45(19):389-391.
6. Stratta P, Badino G. Scombroid poisoning. CMAJ. 2012;184(6):674.
7. Feldman KA, Werner SB, Cronan S, et al. A large outbreak of scombroid fish poisoning associated with eating escolar fish (Lepidocybium flavobrunneum). Epidemiol Infect. 2005;133(1):29-33.