Clinical Toxicology Past Paper (Uruk University, 2025-2024) PDF

Uruk University 5th Stage College of Pharmacy First Course Clinical Toxicology Dr. Reem Ghanim Hussein Lecturer at College of Pharmacy...

Uruk University 5th Stage College of Pharmacy First Course Clinical Toxicology Dr. Reem Ghanim Hussein Lecturer at College of Pharmacy Uruk University 2025 - 2024 Venomous animals Acute poisoning by venomous animals is common in tropical and subtropical climates. The precise chemical composition and pathophysiology of animal venoms is incompletely known and thus the range of specific treatment is limited. The general principles of intensive supportive therapy should be followed in the management of these poisonings.  1. Snake bite There are over 3000 species of snake in the world, but only about 250 are venomous. Poisonous snakes may be divided into two types according to the types of fangs: Family Common names Viperides (foldable fangs) Rattlesnakes ‫ام االجراس‬ Saw scaled vipers (In Iraq) Desert horn Viper (In Iraq) Elapidae (fixed fangs) Cobras (in Iraq) Mambas Sea snakes Saw scaled viper Cobra Desert horn viper  Rattlesnake Every year 30.000 people die from snakebites in the world, the great majority being in India and South-East Asia. In Europe the mortality is less than I per cent of the total and in the United Kingdom deaths from this cause are rare. Snake bites occur most often in children, who have disturbed the snakes as a result of curiosity, or in men, who have disturbed them in the course of their work. Snake venomous contain enzymes, non-enzymatic proteins and other substances such as acetyl choline and 5-hydroxytryptamine. Apart from the direct effects of these compounds they also provoke tissue production of other inflammatory agents such as kinins, histamines and slow reacting substance.  The severity of the toxic effects of snake bite depend on the type and quantity of venom injected. This in turn depends on the age, size and sex of the snake and bites occurring at night are more venomous than during the day. In the case of hibernating snakes, the venom is particularly potent just after hibernation is over. Clinical features Venomous snakes leave characteristically two or occasionally one fang mark, whereas bites from non-poisonous snakes produce a semi-circular set of tooth marks 1. Local effects: these may be of no more than a mild inflammatory reaction or slight bruising. Tissue necrosis is particularly possible, however, in bites from Viperidae and Crotalidae the necrosis occurs several days after the bite, but is preceded by marked pain and swelling. 2. Systemic effects: venom from Crotalidae, Viperidae and Elapidae may cause the following effects. GIT: nausea and vomiting. CVS: hypotension is common due to vasodilatation and hypovolaemia. CNS: drowsiness, muscular weakness, which may result in dipilopia and difficulty with speech and swallowing. In severe cases ventilatory paralysis may occur, and coma and convulsions may develop. Sensory function remains normal. Haematological system: increased blood coagulability may result from rattlesnake bite, whereas with the Malayan Pit Viper a prolonged coagulation defect with extensive ecchymoses and general bleeding tendency may occur due to a very low plasma fibrinogen. Sea snake bite characteristically result in marked polymyositis. Muscle enzymes and plasma potassium levels are elevated and myoglobinuria with renal failure may occur. The muscle damage is so severe that patients may have marked weakness for several months.  Treatment There are a number of popular misconception regarding the management of snake bite. There is no evidence that there is any value in the use of bands or incision and suction of the injection site, and in unskilled hands these maneuvers may be even harmful. Cooling of the bite area, the administration of antihistamines and corticosteroids have all been advocated but none of these are considered helpful now in snake bite. These methods of treatment, therefore, should be avoided. Recommended treatment consist of: 1. Careful cleansing of the wound with sterile saline or water. 2. Immobilisation is valuable treatment, particularly for the local effects. 3. Intensive supportive therapy. 4. Inject tetanus antitoxin, or if the victim has previously been inoculated against tetanus, a booster dose of tetanus toxoid. 5. Inject crystalline penicillin by I.M. 6. Sedation and analgesic may be required. 7. Antivenins.  As snake venoms are largely protein, they are antigenic. Many antivenins are polyvalent containing antibodies to several venoms. They are ineffective to certain viper and elapidine venoms, and often provoke serious allergic reactions which may be fatal. Their use, therefore, must be considered very carefully. Antivenins are indicated only when systemic effects developed or when extensive local tissue damage is presented. A test dose should always be given before administrating the full therapeutic dose. 2. Insect bites Stings from ants, bees, wasps and hornets seldom cause severe toxic effects apart from local pain and swelling, unless the bite is on the mouth or tongue when the associated swelling may cause respiratory distress. Rarely deaths have been reported from very extensive stings or more commonly due to severe allergic reactions, especially to bee stings. Bee stings are alkaline, while wasp, and hornet stings are acid. If the local reaction is marked an antihistamine given systemically is helpful. In severe allergic reactions S.C. adrenaline 1:1000 (0.5ml) and hydrocortisone 100 mg I.V. may be life-saving.  3. Spider bites Poisonous spiders live in warm climates. The black Widow spider and the Funnel Web spider are quite frequent causes of poisonous bites. They commonly live outhouses, basements and foundations of houses and outside lavatories, children and workmen are most often the victims. Death occurs in up to 6 per cent of cases, especially in young children. Clinical features The initial bite may be unnoticed. Within about an hour, however, the following occur: 1. Locomotor disorders: generalized muscular pains and stiffness, burning sensation of feet. 2. Gastrointestinal system: nausea and vomiting. If there is marked abdominal rigidity a mistaken diagnosis of peritonitis may be made. 3. Salivation. 4. Metabolic disorders: pyrexia and sweating. 5. Leucocytosis, mild hypertension and a macular rash may also occur.  Treatment 1. Cleanse the bite with sterile saline or water. 2. Analgesics for relief of pain. 10-20 ml of 10% calcium gluconate by slow IV injection. 3. If secondary infection occurs systemic antibiotics. 4. Intensive supportive therapy. 5. If the systemic features are severe administer the specific antivenin, if this is available. Camel spiders can grow to be as large as dinner plates. It can cross desert sand at speeds up to 25 MPH, making screaming noises as they run. It can jump several feet in the air. Camel spiders eat the stomachs of camels and lay their eggs there, hence the name “camel spider.” Camel spiders eat or chew on people while they sleep. Their venom numbs the area so people can't feel the bites. Camel spiders are not venomous, and though their bites are painful, they are not deadly to humans.  Because of its large jaws, a camel spider can leave a significant wound in human skin. These spiders don't produce venom, but you may get an infection due to the open wound. You may also experience swelling around the bite wound and mild to intense bleeding. 4. Scorpions These nocturnal creatures live in the tropics or sub-tropics. The sting is rarely fatal. Clinical features Marked local pain occurs after the sting. Subsequently sweating, numbness and hyperesthesia may develop. In severe cases, central respiratory and cardiac depression may be marked. Treatment 1. Cleanse the sting. 2. Analgesic for the pain. 3. Intensive supportive therapy.  Venomous sea animals 1. Sting rays These fishes live in warm seas and they present a hazard usually to bathers, who accidentally stand on the fish lying in the sand. The venom contains a thermolabile toxin. Fatalities are uncommon and usually result from extensive injury, especially if the sting sheath remains in the wound. Clinical features Usually the sting results in a sharp wound and severe local pain. Systemic features may develop and include hypotension, oculogyric crises and convulsions. Treatment 1. Incision and suction of the wound should not be done. 2. Careful cleansing of the wound with surgical examination if the sting sheath has been retained. The wound should be immersed in the hottest water tolerable in an attempt to destroy the toxin. Local anaesthetic, systemic analgesic and corticosteroids are often helpful. 3. Intensive supportive therapy in severe cases.  2. Jelly fish Clinical features Local pain is the main effect. Physalia are more sever and pain may be very marked and generalised muscle pains, colic, nausea and breathlessness with cyanosis may result. Death from physalia stings may occur rapidly within minutes or be delayed for some hours. Treatment 1. Any tentacles still adherent to the bather must be removed with care, by adhesive tape, and on no account should they be brushed off with a bare hand as the tentacles may be still capable of delivering a sting for many hours after removal from the water. 2. Analgesic for pain, local anaesthetic cream are effective. 3. Intensive supportive therapy. Thank You