Poisoning

Question 1

In the absence of trauma, how should an obstructed airway be opened?

Answer 1

With simple measures such as a chin lift or jaw thrust.

Question 2

In who may an oropharyngeal or nasopharyngeal airway be useful?

Answer 2

In patients with reduced consciousness, provided ventilation is adequate.

Question 3

Most poisons that impair consciousness also have what other effect?

Answer 3

Depress respiration.

Question 4

When would oxygen be given as a substitute for adequate ventilation?

Answer 4

In the highest concentration possible in poisoning with carbon monoxide and irritant gases.

Question 5

What is common in severe poisoning with central nervous system depressants, hypo or hypertension?

Answer 5

Hypo. A systolic blood pressure of less than 70mmHg may lead to irreversible brain damage or renal tubular necrosis.

Question 6

How should hypotension be corrected initially?

Answer 6

By raising the foot of the bed and administration of an infusion of either sodium chloride or a colloid.

Question 7

Fluid depletion without hypotension is common after what and why?

Answer 7

Prolonged coma.Aspirin poisoning due to vomiting, sweating and hyperpnoea.

Question 8

Hypertension is less common than hypotension in poisoning, when does it occur?

Answer 8

With sympathomimetic drugs such as amfetamines, phencyclidine, and cocaine.

Question 9

Cardiac conduction defects and arrhythmias can occur in acute poisoning caused by what?

Answer 9

Tricyclic antidepressants.Some antipsychotics.Some antihistamines.

Question 10

Arrythmias often respond to what?

Answer 10

Correction of the underlying hypoxia, acidosis or other biochemical abnormalities.

Question 11

When do ventricular arrythmias require treatment?

Answer 11

When they cause serious hypotension.

Question 12

Hypothermia commonly occurs following overdose with what?

Answer 12

Barbituates or phenothiazines.

Question 13

Hyperthermia can develop in patients who are taking what?

Answer 13

CNS stimulants.Children and the elderly are also at risk when taking therapeutic doses of drugs with antimuscarinic properties.

Question 14

How is hyperthermia managed initially?

Answer 14

Hyperthermia is initially managed by removing all unnecessary clothing and using a fan. Sponging with tepid water will promote evaporation.

Question 15

What type of convulsions do not require treatment?

Answer 15

Short lived, less than 5 minutes.

Question 16

If convulsions are protracted or recur frequently, _________ or ________ should be given by slow IV injection into a large vein in what form?

Answer 16

Lorazepam or diazepam, preferably as an emulsion.

Question 17

Benzodiazepines should not be given by what route for convulsions?

Answer 17

IM

Question 18

What are the alternatives to IV lorazepam/diazepam for treatment of convulsions?

Answer 18

Oromucosal midazolam via buccal route or diazepam rectally.

Question 19

What is methaemoglobinaemia?

Answer 19

Methemoglobinemia (congenital or acquired) occurs when red blood cells (RBCs) contain methemoglobin at levels higher than 1%.Methemoglobinemia can be congenital, which means you’re born with it, or acquired, which means you develop it after being exposed to certain chemicals, medications, or foods.

Question 20

How can drug or chemical induced methaemoglobinaemia be treated?

Answer 20

With methylthioninium chloride if the methaemoglobin concentration is 30% higher, or if symptoms of tissue hypoxia are present despite oxygen therapy.

Question 21

How does methylthionium chloride work in treating methaemoglobinaemia?

Answer 21

It reduces the ferric iron of methaemoglobin back to the ferrous iron of heamoglobin; however in high doses it can itself cause methaemoglobinaemia.

Question 22

How can the absorption of certain poisons be prevented?

Answer 22

When activated charcoal is given by mouth it can bind to many poisons in the GI system, thereby reducing their absorption. The sooner it is given, the more effective it is, but it may be effective up to 1 hour after ingestion of the poison - longer in the case of MR preparations or of drugs with antimuscarinic properties.

Question 23

How can the active elimination of poisons be encouraged?

Answer 23

Repeated doses of activated charcoal by mouth enhance the elimination of some drugs after they have been absorbed. Repeated doses are given after overdosage with:Carbamazepine.DapsonePhenobarbital QuinineTheophylline. Dapsone, also known as diaminodiphenyl sulfone (DDS), is an antibiotic commonly used in combination with rifampicin and clofazimine for the treatment of leprosy.

Question 24

What should activated charcoal not be used for?

Answer 24

Poisoning with:Petroleum distillatesCorrosive substancesAlcoholsMalathion (Malathion is an organophosphate insecticide listed by the American Cancer Society as a probable carcinogen especially linked to prostate cancer.)Cyanides and metal salts such as lithium salts.

Question 25

What are the main features of salicylate poisoning?

Answer 25

HyperventilationTinnitusDeafnessVasodilation Sweating

Question 26

How is salicylate poisoning treated?

Answer 26

In hospital, where plasma salicylate, pH, and electrolytes can be measured. Activated charcoal can be given within 1 hour of ingesting 125mg/kg of aspirin.

Question 27

What are the typical signs of opioid poisoning/overdose?

Answer 27

ComaRespiratory depressionPinpoint pupils

Question 28

What is the specific antidote for opioid poisoning? When is its use indicated?

Answer 28

Naloxone hydrochloride, indicated if there is coma or bradypnoea.

Question 29

Why is close monitoring of naloxone administration and repeated injections often needed?

Answer 29

It has a shorter duration of action than many opioids.

Question 30

The effects of some opioids are only partially reversed by naloxone, what is one example?

Answer 30

Buprenorphine.

Question 31

Why do patients who have taken a paracetamol overdose need to be transferred to hospital urgently?

Answer 31

The only signs will be vomiting and nausea which will pass after the first 24 hours. Liver damage is maximal 3-4 days after paracetamol overdose and may lead to encephalopathy, haemorrhage, hypoglycaemia and death.

Question 32

When can acetyl cysteine be used to protect the liver in paracetamol poisoning?

Answer 32

It protects the liver if infused up to, and possibly beyond, 24 hours of ingesting paracetamol. It is most effective if given with 8 hours of ingestion, after which effectiveness declines.

Question 33

For paracetamol overdosage, how is acetyl cysteine given?

Answer 33

In a total dose that is divided into 3 consecutive intravenous infusions over a total of 21 hours.

Question 34

What does the management of overdose with TCA and SSRIs mostly comprise of?

Answer 34

Activated charcoal within 1 hour if possible, Diazepam/lorazepam etc for convulsions if needed.