Toxicology

·         SPOT TESTS FOR METAL POISONING

1.       Reinsch Test: Copper wire turns. . .

a.       Shiny silver: Mercury (see your BP Instrument...!)

b.      Dull black: Arsenic or Silver.

c.       Shiny black: Bismuth

d.      Dark purple sheen: Antimony & Tin

2.       Gutzeit test for arsenic

a.       Acidification produces arsine gas, which discolors silver nitrate paper

3.       Iron reacts with potassium ferricyanide and ferrous sulfate to produce Prussian Blue

·         METAL POISONING:

Cadmium, which can be found in tobacco smoke, has been implicated in producing not only an acute form of pneumonia, but, with chronic exposure to small concentrations of cadmium vapors, diffuse interstitial pulmonary fibrosis and an increased incidence of emphysema as well.

Nickel can cause contact dermatitis, which is a type IV hypersensitivity reaction,

Mercury toxicity damages the kidneys and the brain. The neurologic symptoms include a tremor due to cerebellar abnormalities, and mental changes. Historically the use of mercury in the hatmaking industry caused these symptoms and resulted in the expression “mad as a hatter.” A famous widespread outbreak of mercury poisoning occurred in the Minamata coastal region of Japan (and led to the term Minamata disease).

Cobalt poisoning can produce a dilated cardiomyopathy.

·         Best body fluid to screen for drugs? (except EtOH)

Urine (Blood is best to screen for EtOH)

·         Cosmetics generally safe (exceptions are wave neutralizer [boric acid] and nail products [acetonitrile, methacrylic acid, nitromethane)

·         Cleaning substances toxic when concentrated (Drano contains 54% NaOH)

·         Plants are variable (Philodendrons contain calcium oxylate crystals causing pain, Foxglove contains digoxin causing side effects)

·         Pharmaceuticals, most frequent are analgesics and cold/cough medicines, Pediatric fatalities often due to excessive iron intake.

·         Tricyclic antidepressants interfere with myocardial conduction and can precipitate ventricular tachycardias or complete heart block. A QRS interval >0.1 second is predictive of poor outcome in these patients. The presence of a large R wave in lead accelerated ventricular rhythm (AVR) is also associated with tricyclics. If these findings are noted, treatment with sodium bicarbonate should be initiated. Sodium bicarbonate helps prevent the sodium-channel blockade that is caused by these medications.

·         Chinese restaurant syndrome: Several hours after the ingestion of Chinese food, a patient may complain of burning and numbness of the face and neck, headache, and, occasionally, severe chest pain. Symptoms can persist for up to 1-2 days. The pathophysiology remains unclear, but monosodium glutamate, a food additive, may be involved, with the glutamate acting as a neurotransmitter. Other studies suggest that the fermentation of typical ingredients in Chinese cooking (e.g., soy sauce, black beans, shrimp paste) may release histamines that account for the symptoms.

·                     LSD:

Only a small amount of ergotamine tartrate is required to produce LSD in large batches.

At higher doses it can produce Synaesthesia.

Adverse health consequences of LSD are comparatively rare, with "bad trips" being the most common adverse reaction.

LSD affects all receptor sites including dopaminergic, adrenergic, serotonin, nicotinic, and histamine receptors.

LSD may trigger a Dissociative fugue state in individuals who are taking certain classes of antidepressants such as lithium salts and tricyclics. In such a state, the user has an impulse to wander, and may not be aware of his or her actions, which can lead to physical injury.

Flashbacks, a psychological phenomenon in which an individual experiences an episode of some of the subjective effects of LSD

Remember, STAY SAFE.

·         Cannabinoids are derived from the resin of Cannabis sativa and 9-tetrahydrocannabinol(9-THC)is its most important pharmacologically active constituent. It's bioavailability after oral ingestion is about 6%. Naloxone and other opioid receptor antagonists block the analgesic actions of cannabinoids. Synthetic cannabinoids reduce arachidonic acid-induced inflammation by inhibiting eicosanoid production. 

·         MERCURY POISONING:

Symptoms: Acid metallic taste, hoarse voice, greyish white coating of tongue, blood-stained stool, circulatory collapse, necrosis of jaw, membranous, colitis, proximal renal tubular necrosis.*
Acrodynia*(Acro-Limbs Odynia-Pain) is seen in mercury poisoning (Pink’s Disease),It is Pain,swelling and parasthesia of Limbs
Mimimata disease—Contamination of fish with mercury, at a place called Minimate Bay in Japan.

Chronic Poisoning: (Hydrar gyrism)

• The symptoms are salivation, sore mouth and throat, fine tremors of the tongue, hands, arms, anemia.

• Shaking palsy is associated with Hg poisoning.

Mercurial tremors are also called hatter’s shakes or glass blower’s shake.(Danbury Tremors)

• Mercurial erethism** is seen in persons working with mercury in mirror manufacturing firms. Erethism is characterized by shyness, timidity, irritability, loss of confidence, mental depression, loss of memory and insomnia. (Psychological symptoms).

• Mercurialentis is a peculiar eye change due to brownish deposit of mercury through the cornea on the anterior lens capsule (Brown-Malt Reflex*). It is bilateral and has no effect on visual acuity

·         Cyanide intoxication is treated by use of a Lilly kit, which contains amyl nitrate gas ampules (one 0.3-mL ampule each minute until sodium nitrate infusion begins) for inhalation. This treatment is followed by intravenous administration of sodium nitrite (300 mg), which acts by converting hemoglobin to methemoglobin. Finally, patients are treated with intravenous sodium thiosulfate (12.5 g), which converts cyanide to less harmful thiocyanate ions. If carboxyhemoglobinemia is present, sodium thiosulfate should be used alone because of the additive toxicity of this condition with methemoglobinemia.