Marine_Envenomation_Complete forensic. Medicine

Marine envenomation forensic medicine

1. Puffer Fish - General Information Puffer fish are considered the second most poisonous vertebrate globally. They inflate their bodies to ward off other aquatic creatures. This inflation is a display to signal their poisonous nature. Puffer fish contain a toxin 1200 times more potent than cyanide. They belong to the species Tetradontidae.

2. Puffer Fish - Toxin and Mechanism The toxin found in puffer fish is called Tetradotoxin (TTX). TTX is classified as a neurotoxin. It functions by blocking sodium channels in excitable tissues. This mechanism disrupts normal nerve and muscle function. The toxin is present in their skin, ovaries, gonads, and liver.

3. Puffer Fish - Clinical Features Symptoms typically begin immediately after ingestion. Initial symptoms include tingling and numbness of the lips and fingers. This is followed by muscular weakness. Vomiting and diarrhea may also occur. Later stages can involve convulsions and coma.

4. Puffer Fish - Severe Clinical Features and Death Paralysis of the diaphragm is a severe symptom. This can lead to breathing difficulty. Death may ultimately occur due to respiratory paralysis. Despite its toxicity, puffer fish has high demand as a dish. Approximately 100 cases of poisoning and 3 deaths per 100,000 eaters occur annually.

5. Puffer Fish - Management and Forensic Importance Treatment for puffer fish poisoning involves symptomatic management. Electrolytes and glucose saline can be administered. Mannitol may be given to reduce neurological symptoms. Trained individuals prepare puffer fish dishes to be poison-free. Forensic analysis would involve identifying the presence of TTX in tissues.

6. Malabar Puffer Fish - A Specific Variety A rare variety, the Indian dwarf fish, is found in India. It is considered the world's smallest puffer fish. They are found in the Pamba river in Kerala, India. Also known as Malabar puffer fish or pea puffer fish. Their maximum length does not exceed one inch.

7. Ciguatera Poisoning - Origin and Accumulation Caused by ciguatoxin (CTN) found in certain algae (dinoflagellates) and protozoa. These algae can proliferate, leading to "red tide" events. The toxin accumulates in herbivorous fish when they consume these algae and protozoa. Larger fish, such as sea bass, grouper, and red snapper, accumulate the poison by eating contaminated herbivorous fish. Ciguatoxin is heat-stable and cannot be destroyed by heating or boiling.

8. Ciguatera Poisoning - Signs and Symptoms Symptoms typically start two to three hours after ingesting the cooked fish. Initial symptoms include abdominal pain, vomiting, and diarrhea. Tingling and numbness of the tongue and lips may also occur. Patients may experience myalgia, muscular weakness, and arthralgia. A characteristic symptom is the reversal of temperature sensation: hot substances feel cold, and cold substances feel hot.

9. Ciguatera Poisoning - Further Symptoms and Treatment Patients may feel as if their teeth are loose and about to fall out. A metallic taste in the mouth is also a common symptom. Headache, low blood pressure, and low heart rate can occur. Death may result from respiratory paralysis. Treatment is symptomatic, and mannitol can be used to reduce cerebral edema and neurological symptoms.

10. Scombroid Poisoning - Causes and Symptoms Species involved include tuna, mahimahi, amberjack, and bonito. These fish have high concentrations of histidine in their bodies. Histidine converts to histamine if the fish is not preserved properly. Allergic reactions typically appear 30 to 90 minutes after consumption. Symptoms include itching, urticaria (hives), and breathlessness.

11. Shellfish Poisoning - Source of Toxin Shellfish are aquatic invertebrates with exoskeletons. Poisonous species include clams, oysters, mussels, and scallops. They feed on certain marine algae containing a potent neurotoxin called Saxitoxin (STX). The poison accumulates in their bodies during certain seasons. Poisoning occurs when these contaminated shellfish are consumed.

12. Shellfish Poisoning - Clinical Presentation Symptoms begin within half an hour after ingestion. The poison affects the peripheral and autonomic nervous systems. It effectively blocks depolarization at the neuromuscular junction, similar to curare. This can lead to muscle weakness and paralysis. Specific symptoms like tingling and numbness may also occur.

13. Venomous Fish - Catfish Some fish, like catfish, dragon fish, and lion fish, have spines that cause poisonous wounds. Catfish belong to the species Heteropneustes. They are named for their cat-like whiskers. Their venom is produced by glandular cells in the epidermal layer covering their spines. Some catfish species can even produce enough electricity to deliver an electric shock.

14. Venomous Fish - Dragon Fish and Others Dragon fish are found in deep seas. Some species of dragon fish possess light-producing photophores. Other venomous fish include certain species of lion fish and muraena (eel). These also have spines that can inflict poisonous wounds. Forensic importance lies in identifying the specific venom and the fish responsible in cases of envenomation.

15. Box Jellyfish - The World's Most Venomous Box jellyfish are considered one of the most venomous animals globally. They have a characteristic box-shaped bell (cap). Remarkably, they possess four eyes on each of the four sides of their cap. Their tentacles contain the potent poison. The box jellyfish is cardiotoxic and can cause sudden cardiac arrest.

16. Box Jellyfish - Envenomation and Fatalities One hundred or more deaths occur worldwide each year due to box jellyfish poisoning. Their tentacles are equipped with biological "booby traps" known as cnidocysts. Upon contact, the tentacles wrap around the body. Venom is then injected into the victim. The rapid onset and severity of symptoms make it highly dangerous.

17. Dart Frogs - Poisonous Amphibians Dart frogs are highly poisonous frogs. They are found in subtropical and tropical regions of the earth. Locations include Bolivia, Brazil, Colombia, and Venezuela. These frogs are small, typically 1-2 inches long, and brightly colored. They secrete poisonous alkaloids from glands in their skin.

18. Dart Frogs - Potency and Forensic Significance A single drop of poison from these frogs can kill a human being within 3 minutes. Their vibrant coloration serves as a warning (aposematism). The alkaloids are accumulated from their diet of insects. Forensic investigations might involve identifying the specific toxins in cases of deliberate poisoning. The unique properties of their toxins make them subjects of scientific study.

19. Polygraph - Lie Detector The polygraph is a device that continuously records several physiological variables. These variables include blood pressure, heart rate, respiration, and electrodermal response (EDR). EDR is also known as galvanic skin response (GSR) or skin conductance response (SCR). Measurements are taken while a series of questions are asked to detect lies. These physiological changes are believed to indicate anxiety from sympathetic stimulation during deception.

20. Polygraph - Procedure and Accuracy The subject is seated with a pneumatic rubber tube on the chest, a blood pressure cuff on the arm, and an electrodermal electrode on a fingertip. Two major testing techniques are used: Relevant-Irrelevant Technique (RIT) and Control Question Technique (CQT). A pretest interview gathers information for "control questions" (CQ). Questions include irrelevant, probable lies, and relevant questions. Examiners claim 90% accuracy for polygraph tests.

21. Polygraph - Admissibility in Courts Lie detection systems are widely used by investigation agencies globally. However, their admissibility in courts of law is generally poor. The US Supreme Court has left admissibility to individual jurisdictions. Courts in the EU, Australia, Canada, and England have not yet considered polygraph test admissibility. Indian courts are also reluctant to consider its admissibility.

22. Brain Fingerprinting (Brain Mapping) - Overview Also known as Quantitative EEG (QEEG), it measures the electrical activity of the brain. Brain fingerprinting was invented by Lawrence Farwell. It is a computer-based test designed to detect and provide evidence of knowledge regarding a crime. The test detects the presence or absence of specific information. It does not determine guilt or innocence.

23. Brain Fingerprinting - Procedure and Uses An elastic cap with 19 electronic sensors is placed on the subject's scalp and connected to an EEG device. The subject is shown stimuli (sounds, words, phrases, pictures) on a computer screen. EEG responses are recorded and analyzed. Farwell developed MERMER, including p300 brain wave responses, claiming high accuracy. Uses include criminal investigation, evaluating Alzheimer's, assessing advertisements, and screening employees.

24. Narcoanalysis - Procedure and Legal Aspects A procedure to obtain information from an individual in a natural sleep-like state. The principle is that imagination, used for lying, is neutralized by making the person semiconscious. Sodium amytal or thiopentone sodium (truth drug/serum) is administered intravenously to induce a trance-like state. Other alternative drugs include scopolamine hydrobromide. A team including an anesthetist, psychiatrist, psychologist, and videographer conducts the test.

25. Narcoanalysis - Legal Admissibility and Constitutionality The Supreme Court has ruled that narcoanalysis, polygraph, and brain fingerprinting require individual consent. Even with consent, results may not be admissible as evidence. Such methods are considered illegal and against Article 20(3) of the constitution ("No person accused of any offence shall be compelled to be a witness against himself"). A 2007 Central Government committee found these procedures "unscientific" and unsuitable for criminal investigation. Therefore, their forensic utility in court is highly contentious.

26. Virtopsy - Virtual Autopsy Virtopsy is a non-surgical postmortem technique. It is conducted by forensic pathologists and radiologists. The name "virtopsy" combines "virtual" and "autopsy," coined by Prof. Richard Dirnofer. It is a clean, bloodless procedure for visualizing and documenting findings. Used in natural and unnatural deaths, mass accidents, gunshot injuries, and child abuse.

27. Virtopsy - Techniques and Applications Employs imaging methods like computed tomography (CT), magnetic resonance imaging (MRI), postmortem angiography, and semi-microradiography to determine cause of death. 3D surface scanning integrates body surface documentation with 3D scene or tool scans. CT is good for foreign objects, fractures, air/gas embolism; MRI for organs and soft tissues. Data can be archived, reproduced, and analyzed elsewhere. Used to investigate ancient mummies and provide detailed reconstructions in strangulation cases.