Poisoning & Environmental Exposures

Question 1

Diphenhydramine

Answer 1

Anti-histamine with anti-cholinergic properties

Question 2

Anticholinergic excess

Treatment

Answer 2

Dry mouth/dry skin (“dry as a bone”)

Blurry vision/mydriasis (“blind as a bat”)

Hyperthermia from impaired heat dissipation (“hot as a hare”)

Urinary retention (“full as a flask”)

Decreased bowel sounds

Cutaneous vasodilation (“red as a beet”)

Delirium or hallucinations (“mad as a hatter”)

Manage with physostigmine, a cholinesterase inhibitor

Question 3

Salicylate intoxication

Signs

Treatment

Answer 3

Signs: Tinnitus, nausea/voming, fever

Treatment: Alkalization of urine with sodium bicarbonate

Question 4

Serotonin syndrome signs

Answer 4

Autonomic hyperactivity (tachycardia, increased bowel sounds, hyperthermia, hypertension)

Mental status changes

Dilated pupils

Neuromuscular findings (clonus, hyperreflexia)

Question 5

Theophylline overdose

Answer 5

Seizures

Hyperthermia

Cardiac arrhythmias

Tachycardia

Hypotension

Question 6

Clinical features & management of tricyclic antidepressant overdose

1. Clinical presentation
2. Management

Answer 6

Benzodiazepines for seizures

Sodium bicarbonate for cardiac toxicity (QRS > 100 ms, ventricular arrhythmias)

Question 7

Caustic ingestion

1. Clinical features
2. Management
3. Complications

Answer 7

Delayed endoscopy increases perforation risk

Any intervention that may cause vomiting is contraindicated

Question 8

Approach to childhood lead poisoning

Answer 8

Capillary (fingerstick) blood specifimens are widely used for initial screening but can have false-positive results.

Question 9

Major toxins produced by combustion (fire) in closed spaces

Answer 9

Hydrogen cyanide (HCN)

Carbon monoxide (CO)

Question 10

Treatment overview for suspected cyanide poisoning

1. Decontamination
2. Respiratory support
3. Cardiovascular support

Answer 10

Question 11

Clinical Presentation of Methemogloninemia

1. History
2. Clinical examination
3. Laboratory findings

4. Treatment

Answer 11

4. Treatment: Methylene blue

Caused by oxidation of ferrous (Fe2+) to ferric (Fe3+) iron in hemoglobin

Left shift in oxygen dissociation curve

Functional anemia due to reduced oxygen delivery to dissues

Arterial blood gas testing measures unbound oxygen

Question 12

Frostbite

1. Clinical findings
2. Managment

Answer 12

Question 13

Arsenic poisoning

1. Mechanism
2. Sources
3. Manifestations
4. Treatment

Answer 13

Diagnosis is confirmed with elevated urine arsenic levels

Question 14

Sulfhemoglobinemia

Answer 14

Occurs after exposure to an oxidative sulfur-containing medication (e.g., sumatriptan, sulfasalazine).

Patients have a blue-green discoloration of blood and mucocutaneous surfaces

Question 15

Co-oximetry testing

Answer 15

Analyzes hemoglobin absorption wavelengths and can identify hemoglobin, methemoglobin, and carboyxhemoglobin.

Question 16

Treatment for lead poisoning

Answer 16

Dimercaprol: Chelating agent

Increases urinary and fecal excretion of lead

Question 17

Treatment of ethylene glycol or methanol ingestion

Answer 17

Fomepizole

Inhibits alcohol dehydrogenase, preventing metabolism of alcohols to their toxic metabolites

Question 18

Treatment for beta blocker or calcium channel overdose

Answer 18

Glucagon

Activates adenylate cyclase, increasing intracellular calcium and improving cardiac contractility

Question 19

Antidote for acetaminophen poisoning

Answer 19

N-acetylcysteine

Restores glutathione, which metabolizes acetaminophen’s toxic metabolite, N-acetyl-p-benzoquinone (NAPQI), to nontoxic metabolites

Question 20

Treatment for cholinergic toxicity (with acetylcholinesterase inhibitors)

Answer 20

Pralidoxime: reactivates cholinesterase enzyme

Atropine

Question 21

Complication of circumferential, full-thickness (third degree burns)

Answer 21

Eschar formation that restricts venous and lymphatic drainage, leading to acute compartment syndrome

Question 22

Iron poisoning

1. Clinical features
2. Diagnostic findings
3. Treatment

Answer 22

Question 23

Features of benzodiazepine overdose

Answer 23

Slurred speech

Unsteady gait

Drowsiness

Can be distinguished from opioid overdose by lack of severe respiratory depression and lack of pupillary constricton.

Distinguished from alcohol or phenytoin overdose by lack of nystagmus.

Question 24

Carbon monoxide poisoning versus Cyanide poisoning versus methemoglobinemia

Answer 24

Carbon monoxide is emitted by automobiles, furnaces, charcoal grills.

Cyanide is released by burning of rubber or plastic.

Pinkish-red skin hue for both.

Methemoglobinemia presents with cyanosis and bluish discoloring of skin.

Question 25

Treatment of iron poisoning

Answer 25

Deferoxamine

Binds ferric iron, allowing urinary excretion