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Question 1
Correct
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A 45-year-old man is brought into the Emergency Department by his wife after taking an overdose of paracetamol. The patient claims that he wants to end it all and refuses to stay in the hospital for treatment. His wife insists that he must be treated because he is not thinking clearly.
Which medication is the primary treatment for paracetamol overdose in an inpatient setting?Your Answer: Acetylcysteine
Explanation:Paracetamol overdose is the most common overdose in the U.K. and is also the leading cause of acute liver failure. The liver damage occurs due to a metabolite of paracetamol called N-acetyl-p-benzoquinoneimine (NAPQI), which depletes the liver’s glutathione stores and directly harms liver cells. Severe liver damage and even death can result from an overdose of more than 12 g or > 150 mg/kg body weight.
The clinical manifestations of paracetamol overdose can be divided into four stages:
Stage 1 (0-24 hours): Patients may not show any symptoms, but common signs include nausea, vomiting, and abdominal discomfort.
Stage 2 (24-48 hours): Right upper quadrant pain and tenderness develop, along with the possibility of hypoglycemia and reduced consciousness.
Stage 3 (48-96 hours): Hepatic failure begins, characterized by jaundice, coagulopathy, and encephalopathy. Loin pain, haematuria, and proteinuria may indicate early renal failure.
Stage 4 (> 96 hours): Hepatic failure worsens progressively, leading to cerebral edema, disseminated intravascular coagulation (DIC), and ultimately death.
The earliest and most sensitive indicator of liver damage is a prolonged INR, which starts to rise approximately 24 hours after the overdose. Liver function tests (LFTs) typically remain normal until 18 hours after the overdose. However, AST and ALT levels then sharply increase and can exceed 10,000 units/L by 72-96 hours. Bilirubin levels rise more slowly and peak around 5 days.
The primary treatment for paracetamol overdose is acetylcysteine. Acetylcysteine is a highly effective antidote, but its efficacy diminishes rapidly if administered more than 8 hours after a significant ingestion. Ingestions exceeding 75 mg/kg are considered significant.
Acetylcysteine should be given based on a 4-hour level or administered empirically if the presentation occurs more than 8 hours after a significant overdose. If the overdose is staggered or the timing is uncertain, empirical treatment is also recommended. The treatment regimen is as follows:
– First dose: 150 mg/kg in 200 mL 5% glucose over 1 hour
– Second dose 50 mg/kg in 500 mL 5% glucose over 4 hours
– Third dose 100 mg/kg in 1000 mL 5% glucose over 16 hours -
This question is part of the following fields:
- Pharmacology & Poisoning
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Question 2
Incorrect
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A 30-year-old woman is diagnosed with depression during the 2nd-trimester of her pregnancy and is started on fluoxetine. As a result of this treatment, the baby develops a complication.
Which of the following complications is the most likely to occur due to the use of this medication during pregnancy?Your Answer: Haemorrhagic disease of the newborn
Correct Answer: Persistent pulmonary hypertension of the newborn
Explanation:During the third trimester of pregnancy, the use of selective serotonin reuptake inhibitors (SSRIs) has been associated with a discontinuation syndrome and persistent pulmonary hypertension of the newborn. It is important to be aware of the adverse effects of various drugs during pregnancy. For example, ACE inhibitors like ramipril, if given in the second and third trimester, can cause hypoperfusion, renal failure, and the oligohydramnios sequence. Aminoglycosides such as gentamicin can lead to ototoxicity and deafness. High doses of aspirin can result in first-trimester abortions, delayed onset labor, premature closure of the fetal ductus arteriosus, and fetal kernicterus. However, low doses (e.g., 75 mg) do not pose significant risks. Late administration of benzodiazepines like diazepam during pregnancy can cause respiratory depression and a neonatal withdrawal syndrome. Calcium-channel blockers, if given in the first trimester, may cause phalangeal abnormalities, while their use in the second and third trimester can lead to fetal growth retardation. Carbamazepine has been associated with hemorrhagic disease of the newborn and neural tube defects. Chloramphenicol can cause grey baby syndrome. Corticosteroids, if given in the first trimester, may cause orofacial clefts. Danazol, if administered in the first trimester, can result in masculinization of the female fetuses genitals. Pregnant women should avoid handling crushed or broken tablets of finasteride as it can be absorbed through the skin and affect male sex organ development. Haloperidol, if given in the first trimester, may cause limb malformations, while its use in the third trimester increases the risk of extrapyramidal symptoms in the neonate. Heparin can lead to maternal bleeding and thrombocytopenia. Isoniazid can cause maternal liver damage and neuropathy and seizures in the neonate. Isotretinoin carries a high risk of teratogenicity, including multiple congenital malformations, spontaneous abortion, and intellectual disability. The use of lithium in the first trimester increases the risk of fetal cardiac malformations, while its use in the second and third trimesters can result in hypotonia, lethargy, feeding problems, hypothyroidism, goiter, and nephrogenic diabetes insipidus.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 3
Incorrect
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A 68-year-old is brought to the emergency department by his son. The patient complained of feeling sick. On checking the patient's medication, the son suspects he may have taken an excessive amount of digoxin tablets in the past few days. You are worried about digoxin toxicity. Which electrolyte imbalance is most frequently linked to triggering digoxin toxicity?
Your Answer: Hypermagnesaemia
Correct Answer: Hypokalaemia
Explanation:Digoxin toxicity can be triggered by hypokalaemia, a condition characterized by low levels of potassium in the body. This occurs because digoxin competes with potassium for binding sites, and when potassium levels are low, there is less competition for digoxin to bind to these sites. Additionally, other factors such as hypomagnesaemia, hypercalcaemia, hypernatraemia, and acidosis can also contribute to digoxin toxicity.
Further Reading:
Digoxin is a medication used for rate control in atrial fibrillation and for improving symptoms in heart failure. It works by decreasing conduction through the atrioventricular node and increasing the force of cardiac muscle contraction. However, digoxin toxicity can occur, and plasma concentration alone does not determine if a patient has developed toxicity. Symptoms of digoxin toxicity include feeling generally unwell, lethargy, nausea and vomiting, anorexia, confusion, yellow-green vision, arrhythmias, and gynaecomastia.
ECG changes seen in digoxin toxicity include downsloping ST depression with a characteristic Salvador Dali sagging appearance, flattened, inverted, or biphasic T waves, shortened QT interval, mild PR interval prolongation, and prominent U waves. There are several precipitating factors for digoxin toxicity, including hypokalaemia, increasing age, renal failure, myocardial ischaemia, electrolyte imbalances, hypoalbuminaemia, hypothermia, hypothyroidism, and certain medications such as amiodarone, quinidine, verapamil, and diltiazem.
Management of digoxin toxicity involves the use of digoxin specific antibody fragments, also known as Digibind or digifab. Arrhythmias should be treated, and electrolyte disturbances should be corrected with close monitoring of potassium levels. It is important to note that digoxin toxicity can be precipitated by hypokalaemia, and toxicity can then lead to hyperkalaemia.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 4
Incorrect
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A 35-year-old patient with asthma comes in with acute theophylline toxicity. Along with theophylline, they use salbutamol and beclomethasone inhalers.
What factor is most likely to have caused this episode?Your Answer: Smoking
Correct Answer: Viral infection
Explanation:Theophylline is a medication used to treat severe asthma. It is a bronchodilator that comes in modified-release forms, which can maintain therapeutic levels in the blood for 12 hours. Theophylline works by inhibiting phosphodiesterase and blocking the breakdown of cyclic AMP. It also competes with adenosine on A1 and A2 receptors.
Achieving the right dose of theophylline can be challenging because there is a narrow range between therapeutic and toxic levels. The half-life of theophylline can be influenced by various factors, further complicating dosage adjustments. It is recommended to aim for serum levels of 10-20 mg/l six to eight hours after the last dose.
Unlike many other medications, the specific brand of theophylline can significantly impact its effects. Therefore, it is important to prescribe theophylline by both its brand name and generic name.
Several factors can increase the half-life of theophylline, including heart failure, cirrhosis, viral infections, and certain drugs. Conversely, smoking, heavy drinking, and certain medications can decrease the half-life of theophylline.
There are several drugs that can either increase or decrease the plasma concentration of theophylline. Calcium channel blockers, cimetidine, fluconazole, macrolides, methotrexate, and quinolones can increase the concentration. On the other hand, carbamazepine, phenobarbitol, phenytoin, rifampicin, and St. John’s wort can decrease the concentration.
The clinical symptoms of theophylline toxicity are more closely associated with acute overdose rather than chronic overexposure. Common symptoms include headache, dizziness, nausea, vomiting, abdominal pain, rapid heartbeat, dysrhythmias, seizures, mild metabolic acidosis, low potassium, low magnesium, low phosphates, abnormal calcium levels, and high blood sugar.
Seizures are more prevalent in acute overdose cases, while chronic overdose typically presents with minimal gastrointestinal symptoms. Cardiac dysrhythmias are more common in chronic overdose situations compared to acute overdose.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 5
Incorrect
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You are managing a 35-year-old male who has ingested an excessive amount of medication. You intend to administer N-acetylcysteine (NAC). The patient inquires about the likelihood of experiencing any side effects. What proportion of patients experience adverse reactions to NAC?
Your Answer: 10%
Correct Answer: 20%
Explanation:Paracetamol poisoning occurs when the liver is unable to metabolize paracetamol properly, leading to the production of a toxic metabolite called N-acetyl-p-benzoquinone imine (NAPQI). Normally, NAPQI is conjugated by glutathione into a non-toxic form. However, during an overdose, the liver’s conjugation systems become overwhelmed, resulting in increased production of NAPQI and depletion of glutathione stores. This leads to the formation of covalent bonds between NAPQI and cell proteins, causing cell death in the liver and kidneys.
Symptoms of paracetamol poisoning may not appear for the first 24 hours or may include abdominal symptoms such as nausea and vomiting. After 24 hours, hepatic necrosis may develop, leading to elevated liver enzymes, right upper quadrant pain, and jaundice. Other complications can include encephalopathy, oliguria, hypoglycemia, renal failure, and lactic acidosis.
The management of paracetamol overdose depends on the timing and amount of ingestion. Activated charcoal may be given if the patient presents within 1 hour of ingesting a significant amount of paracetamol. N-acetylcysteine (NAC) is used to increase hepatic glutathione production and is given to patients who meet specific criteria. Blood tests are taken to assess paracetamol levels, liver function, and other parameters. Referral to a medical or liver unit may be necessary, and psychiatric follow-up should be considered for deliberate overdoses.
In cases of staggered ingestion, all patients should be treated with NAC without delay. Blood tests are also taken, and if certain criteria are met, NAC can be discontinued. Adverse reactions to NAC are common and may include anaphylactoid reactions, rash, hypotension, and nausea. Treatment for adverse reactions involves medications such as chlorpheniramine and salbutamol, and the infusion may be stopped if necessary.
The prognosis for paracetamol poisoning can be poor, especially in cases of severe liver injury. Fulminant liver failure may occur, and liver transplant may be necessary. Poor prognostic indicators include low arterial pH, prolonged prothrombin time, high plasma creatinine, and hepatic encephalopathy.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 6
Incorrect
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A 75-year-old man with a history of heart failure and atrial fibrillation comes in with severe vomiting and diarrhea. Blood tests are done, and an electrolyte imbalance is observed.
Which electrolyte imbalance poses the greatest risk for a patient who is on digoxin?Your Answer: Hypomagnasaemia
Correct Answer: Hypokalaemia
Explanation:Digoxin is a medication used to treat atrial fibrillation and flutter as well as congestive cardiac failure. It belongs to a class of drugs called cardiac glycosides. Digoxin works by inhibiting the Na/K ATPase pump in the cardiac myocytes, which are the cells of the heart. This inhibition leads to an increase in the concentration of sodium inside the cells and indirectly increases the availability of calcium through the Na/Ca exchange mechanism. The rise in intracellular calcium levels results in a positive inotropic effect, meaning it strengthens the force of the heart’s contractions, and a negative chronotropic effect, meaning it slows down the heart rate.
However, it’s important to note that digoxin can cause toxicity, which is characterized by high levels of potassium in the blood, known as hyperkalemia. Normally, the Na/K ATPase pump helps maintain the balance of sodium and potassium by allowing sodium to leave the cells and potassium to enter. When digoxin blocks this pump, it disrupts this balance and leads to higher levels of potassium in the bloodstream.
Interestingly, the risk of developing digoxin toxicity is higher in individuals with low levels of potassium, known as hypokalemia. This is because digoxin binds to the ATPase pump at the same site as potassium. When potassium levels are low, digoxin can more easily bind to the ATPase pump and exert its inhibitory effects.
In summary, digoxin is a cardiac glycoside that is used to treat certain heart conditions. It works by inhibiting the Na/K ATPase pump, leading to increased intracellular calcium levels and resulting in a positive inotropic effect and negative chronotropic effect. However, digoxin can also cause toxicity, leading to high levels of potassium in the blood. The risk of toxicity is higher in individuals with low potassium levels.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 7
Incorrect
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A 22-year-old man is brought in by ambulance having taken an overdose of his father's diazepam tablets.
What is the SINGLE most appropriate initial drug treatment in this situation?Your Answer: Flumazenil IV 0.5 mg
Correct Answer: Flumazenil IV 200 μg
Explanation:Flumazenil is a specific antagonist for benzodiazepines that can be beneficial in certain situations. It acts quickly, taking less than 1 minute to take effect, but its effects are short-lived and only last for less than 1 hour. The recommended dosage is 200 μg every 1-2 minutes, with a maximum dose of 3mg per hour.
It is important to avoid using Flumazenil if the patient is dependent on benzodiazepines or is taking tricyclic antidepressants. This is because it can trigger a withdrawal syndrome in these individuals, potentially leading to seizures or cardiac arrest.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 8
Incorrect
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A 35-year-old man with a history of bipolar affective disorder presents with symptoms suggestive of lithium toxicity.
Which of the following symptoms is MOST likely to be present?Your Answer: SIADH
Correct Answer: Clonus
Explanation:Lithium toxicity presents with various symptoms, including nausea and vomiting, diarrhea, tremor, ataxia, confusion, increased muscle tone, clonus, nephrogenic diabetes insipidus, convulsions, coma, and renal failure. One notable symptom associated with digoxin toxicity is xanthopsia.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 9
Incorrect
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A 45-year-old man develops corneal microdeposits as a side effect of a gastrointestinal drug that he has been prescribed.
Which of the following drugs is MOST likely to be causing this?Your Answer: Bumetanide
Correct Answer: Amiodarone
Explanation:Corneal microdeposits are found in almost all individuals (over 90%) who have been taking amiodarone for more than six months, particularly at doses higher than 400 mg/day. These deposits generally do not cause any symptoms, although approximately 10% of patients may experience a perception of a ‘bluish halo’ around objects they see.
Amiodarone can also have other effects on the eye, but these are much less common, occurring in only 1-2% of patients. These effects include optic neuropathy, nonarteritic anterior ischemic optic neuropathy (N-AION), optic disc swelling, and visual field defects.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 10
Incorrect
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A 3-year-old girl has consumed a whole packet of ibuprofen tablets that she discovered in her father's bag.
Which of the following symptoms of ibuprofen overdose is more frequently observed in children compared to adults?Your Answer: Tinnitus
Correct Answer: Hypoglycaemia
Explanation:Hyperpyrexia and hypoglycemia are more frequently observed in children than in adults due to salicylate poisoning. Both adults and children may experience common clinical manifestations such as nausea, vomiting, tinnitus, deafness, sweating, dehydration, hyperventilation, and cutaneous flushing. However, it is important to note that xanthopsia is associated with digoxin toxicity, not salicylate poisoning.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 11
Correct
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You assess a patient with nausea, vomiting, restlessness, and palpitations. She is on theophylline for the treatment of her COPD. You suspect toxicity and order blood tests for evaluation.
What is the target range for theophylline levels?Your Answer: 10-20 mg/L
Explanation:The therapeutic range for theophylline is quite limited, ranging from 10 to 20 micrograms per milliliter (10-20 mg/L). It is important to estimate the plasma concentration of aminophylline during long-term treatment as it can provide valuable information.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 12
Incorrect
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A 42 year old woman is brought into the emergency department by ambulance after confessing to consuming a significant amount of amitriptyline following a breakup. The patient then experiences a seizure. Which medication is the most suitable for managing the seizure?
Your Answer: Phenytoin
Correct Answer: Diazepam
Explanation:When it comes to managing seizures in cases of TCA overdose, benzodiazepines are considered the most effective treatment. Diazepam or lorazepam are commonly administered for this purpose. However, it’s important to note that lamotrigine and carbamazepine are typically used for preventing seizures rather than for immediate seizure control.
Further Reading:
Tricyclic antidepressant (TCA) overdose is a common occurrence in emergency departments, with drugs like amitriptyline and dosulepin being particularly dangerous. TCAs work by inhibiting the reuptake of norepinephrine and serotonin in the central nervous system. In cases of toxicity, TCAs block various receptors, including alpha-adrenergic, histaminic, muscarinic, and serotonin receptors. This can lead to symptoms such as hypotension, altered mental state, signs of anticholinergic toxicity, and serotonin receptor effects.
TCAs primarily cause cardiac toxicity by blocking sodium and potassium channels. This can result in a slowing of the action potential, prolongation of the QRS complex, and bradycardia. However, the blockade of muscarinic receptors also leads to tachycardia in TCA overdose. QT prolongation and Torsades de Pointes can occur due to potassium channel blockade. TCAs can also have a toxic effect on the myocardium, causing decreased cardiac contractility and hypotension.
Early symptoms of TCA overdose are related to their anticholinergic properties and may include dry mouth, pyrexia, dilated pupils, agitation, sinus tachycardia, blurred vision, flushed skin, tremor, and confusion. Severe poisoning can lead to arrhythmias, seizures, metabolic acidosis, and coma. ECG changes commonly seen in TCA overdose include sinus tachycardia, widening of the QRS complex, prolongation of the QT interval, and an R/S ratio >0.7 in lead aVR.
Management of TCA overdose involves ensuring a patent airway, administering activated charcoal if ingestion occurred within 1 hour and the airway is intact, and considering gastric lavage for life-threatening cases within 1 hour of ingestion. Serial ECGs and blood gas analysis are important for monitoring. Intravenous fluids and correction of hypoxia are the first-line therapies. IV sodium bicarbonate is used to treat haemodynamic instability caused by TCA overdose, and benzodiazepines are the treatment of choice for seizure control. Other treatments that may be considered include glucagon, magnesium sulfate, and intravenous lipid emulsion.
There are certain things to avoid in TCA overdose, such as anti-arrhythmics like quinidine and flecainide, as they can prolonged depolarization.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 13
Incorrect
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A 14 year old female is brought to the emergency department by her parents approximately 90 minutes after taking an overdose. The patient tells you she was at her friend's house and they got into an argument which ended with her friend telling her she was ending their friendship. The patient grabbed a bottle of pills from the bathroom and swallowed all of them before leaving. She didn't tell her friend she had taken the pills and wanted her to feel guilty but now regrets her actions. The patient tells you she didn't read the name on the bottle and threw the bottle away as she walked home. The patient also tells you she didn't see how many pills were in the bottle but thinks there were 20-30 of them. Several attempts to contact the patient's friend to try and clarify the identity of the pills are unsuccessful. The patient advises you she feels nauseated and has ringing in her ears. You also note the patient is hyperventilating. A blood gas sample is taken and is shown below:
Parameter Result
pH 7.49
pO2 14.3 KPa
pCO2 3.4 KPa
HCO3- 25 mmol/L
BE -1
Which of the following best describes the acid base disturbance?Your Answer: Metabolic alkalosis
Correct Answer: Respiratory alkalosis
Explanation:An elevated pH (normal range 7.34-7.45) suggests alkalosis. A low pCO2 (normal range 4.4-6.0 Kpa) indicates that the respiratory system is causing the alkalosis. The metabolic system, on the other hand, is not contributing to either alkalosis or acidosis as both the bicarbonate and base excess levels are within the normal ranges.
Further Reading:
Salicylate poisoning, particularly from aspirin overdose, is a common cause of poisoning in the UK. One important concept to understand is that salicylate overdose leads to a combination of respiratory alkalosis and metabolic acidosis. Initially, the overdose stimulates the respiratory center, leading to hyperventilation and respiratory alkalosis. However, as the effects of salicylate on lactic acid production, breakdown into acidic metabolites, and acute renal injury occur, it can result in high anion gap metabolic acidosis.
The clinical features of salicylate poisoning include hyperventilation, tinnitus, lethargy, sweating, pyrexia (fever), nausea/vomiting, hyperglycemia and hypoglycemia, seizures, and coma.
When investigating salicylate poisoning, it is important to measure salicylate levels in the blood. The sample should be taken at least 2 hours after ingestion for symptomatic patients or 4 hours for asymptomatic patients. The measurement should be repeated every 2-3 hours until the levels start to decrease. Other investigations include arterial blood gas analysis, electrolyte levels (U&Es), complete blood count (FBC), coagulation studies (raised INR/PTR), urinary pH, and blood glucose levels.
To manage salicylate poisoning, an ABC approach should be followed to ensure a patent airway and adequate ventilation. Activated charcoal can be administered if the patient presents within 1 hour of ingestion. Oral or intravenous fluids should be given to optimize intravascular volume. Hypokalemia and hypoglycemia should be corrected. Urinary alkalinization with intravenous sodium bicarbonate can enhance the elimination of aspirin in the urine. In severe cases, hemodialysis may be necessary.
Urinary alkalinization involves targeting a urinary pH of 7.5-8.5 and checking it hourly. It is important to monitor for hypokalemia as alkalinization can cause potassium to shift from plasma into cells. Potassium levels should be checked every 1-2 hours.
In cases where the salicylate concentration is high (above 500 mg/L in adults or 350 mg/L in children), sodium bicarbonate can be administered intravenously. Hemodialysis is the treatment of choice for severe poisoning and may be indicated in cases of high salicylate levels, resistant metabolic acidosis, acute kidney injury, pulmonary edema, seizures and coma.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 14
Incorrect
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A 40-year-old patient with asthma comes to the Emergency Department for an unrelated medical issue. While reviewing their medications, you find out that they are taking theophylline as part of their asthma treatment.
Which ONE of the following medications should be avoided?Your Answer: Cyclizine
Correct Answer: Ciprofloxacin
Explanation:Ciprofloxacin is known to inhibit the activity of cytochrome P450 enzymes, which can lead to increased levels of theophylline in the blood. Therefore, it is recommended to avoid prescribing ciprofloxacin and theophylline together. For more information on the interactions between these two medications, you can refer to the relevant section on theophylline interactions in the British National Formulary (BNF).
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 15
Incorrect
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A 35-year-old woman is given a medication for a medical condition during her pregnancy. As a result, the newborn experiences multiple significant birth defects, such as neural tube, craniofacial, and limb abnormalities.
Which of the following medications is the most probable culprit for these anomalies?Your Answer: Amoxicillin
Correct Answer: Sodium valproate
Explanation:Sodium valproate is considered the most high-risk anti-epileptic drug during pregnancy. A recent review found that up to 40% of children born to women who took sodium valproate while pregnant experienced some form of adverse effect. These effects include a 1.5% risk of neural tube defects and an increased risk of cardiac, craniofacial, and limb defects. Additionally, there is a significant risk of neurodevelopmental problems in childhood.
Here is a list outlining the commonly encountered drugs that have adverse effects during pregnancy:
ACE inhibitors (e.g. ramipril): If given in the second and third trimester, these drugs can cause hypoperfusion, renal failure, and the oligohydramnios sequence.
Aminoglycosides (e.g. gentamicin): These drugs can cause ototoxicity and deafness in the fetus.
Aspirin: High doses of aspirin can lead to first-trimester abortions, delayed onset labor, premature closure of the fetal ductus arteriosus, and fetal kernicterus. However, low doses (e.g. 75 mg) do not pose a significant risk.
Benzodiazepines (e.g. diazepam): When given late in pregnancy, these drugs can cause respiratory depression and a neonatal withdrawal syndrome.
Calcium-channel blockers: If given in the first trimester, these drugs can cause phalangeal abnormalities. If given in the second and third trimester, they can lead to fetal growth retardation.
Carbamazepine: This drug can cause hemorrhagic disease of the newborn and neural tube defects.
Chloramphenicol: Use of this drug can result in gray baby syndrome.
Corticosteroids: If given in the first trimester, corticosteroids may cause orofacial clefts in the fetus.
Danazol: If given in the first trimester, this drug can cause masculinization of the female fetuses genitals.
Finasteride: Pregnant women should avoid handling finasteride as crushed or broken tablets can be absorbed through the skin and affect male sex organ development.
Haloperidol: If given in the first trimester, this drug may cause limb malformations. If given in the third trimester, there is an increased risk of extrapyramidal symptoms in the neonate.
Heparin: Maternal bleeding and thrombocytopenia are potential adverse outcomes.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 16
Correct
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You review a 52-year-old woman who has recently been prescribed antibiotics for a urinary tract infection (UTI). She has a history of COPD and is currently taking salbutamol and Seretide inhalers and Phyllocontin Continus. Since starting the antibiotics, she has been experiencing nausea, vomiting, and abdominal pain.
Which SINGLE antibiotic is she most likely to have been prescribed for her UTI?Your Answer: Ciprofloxacin
Explanation:Phyllocontin Continus contains aminophylline, which is a combination of theophylline and ethylenediamine. It is a bronchodilator that is commonly used to manage COPD and asthma.
In this case, the woman is showing symptoms of theophylline toxicity, which may have been triggered by the antibiotic prescribed for her urinary tract infection. Quinolone antibiotics, like ciprofloxacin, can increase the concentration of theophyllines in the blood, leading to toxicity.
There are other medications that can also interact with theophyllines. These include macrolide antibiotics such as clarithromycin, allopurinol, antifungals like ketoconazole, and calcium-channel blockers such as amlodipine. It is important to be aware of these interactions to prevent any potential complications.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 17
Incorrect
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A 28-year-old woman is diagnosed with tuberculosis during her pregnancy and given isoniazid as part of her medication. As a result of this treatment, the newborn develops a defect.
Which of the following defects is the most probable outcome due to the use of this medication during pregnancy?Your Answer:
Correct Answer: Neuropathy
Explanation:The standard drug regimen for tuberculosis is generally safe to use during pregnancy, with the exception of streptomycin which should be avoided. However, the use of isoniazid during pregnancy has been associated with potential risks such as liver damage in the mother and the possibility of neuropathy and seizures in the newborn.
Here is a list outlining some commonly encountered drugs that have adverse effects during pregnancy:
ACE inhibitors (e.g. ramipril): If taken during the second and third trimesters, these medications can lead to reduced blood flow, kidney failure, and a condition called oligohydramnios.
Aminoglycosides (e.g. gentamicin): These drugs can cause ototoxicity, resulting in hearing loss in the baby.
Aspirin: High doses of aspirin can increase the risk of first trimester abortions, delayed labor, premature closure of the fetal ductus arteriosus, and a condition called fetal kernicterus. However, low doses (e.g. 75 mg) do not pose significant risks.
Benzodiazepines (e.g. diazepam): When taken late in pregnancy, these medications can cause respiratory depression in the baby and lead to a withdrawal syndrome.
Calcium-channel blockers: If taken during the first trimester, these drugs can cause abnormalities in the fingers and toes. If taken during the second and third trimesters, they may result in fetal growth retardation.
Carbamazepine: This medication can increase the risk of hemorrhagic disease in the newborn and neural tube defects.
Chloramphenicol: Use of this drug in newborns can lead to a condition known as grey baby syndrome.
Corticosteroids: If taken during the first trimester, corticosteroids may increase the risk of orofacial clefts in the baby.
Danazol: When taken during the first trimester, this medication can cause masculinization of the female fetuses genitals.
Finasteride: Pregnant women should avoid handling crushed or broken tablets of finasteride as it can be absorbed through the skin and affect the development of male sex organs in the baby.
Haloperidol: If taken during the first trimester, this medication may increase the risk of limb malformations. If taken during the third trimester, it can lead to an increased risk of extrapyramidal symptoms in the newborn.
Heparin: Use of heparin during pregnancy is associated with an acceptable bleeding rate and a low rate of thrombotic recurrence in the mother.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 18
Incorrect
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A 25-year-old woman arrives at the Emergency Department after ingesting an overdose 30 minutes ago. She is currently showing no symptoms and her vital signs are stable. The attending physician recommends administering a dose of activated charcoal.
Which of the following substances or toxins is activated charcoal effective in decontaminating?Your Answer:
Correct Answer: Amitriptyline
Explanation:Activated charcoal is a commonly used substance for decontamination in cases of poisoning. Its main function is to adsorb the molecules of the ingested toxin onto its surface.
Activated charcoal is a chemically inert form of carbon. It is a fine black powder that has no odor or taste. It is produced by subjecting carbonaceous matter to high temperatures, a process known as pyrolysis, and then concentrating it with a zinc chloride solution. This creates a network of pores within the charcoal, giving it a large absorptive area of approximately 3,000 m2/g. This porous structure helps prevent the absorption of the harmful toxin by up to 50%.
The usual dosage of activated charcoal is 50 grams for adults and 1 gram per kilogram of body weight for children. It can be administered orally or through a nasogastric tube. It is important to give the charcoal within one hour of ingestion, and it may be repeated after one hour if necessary.
However, there are certain situations where activated charcoal should not be used. If the patient is unconscious or in a coma, there is a risk of aspiration, so the charcoal should not be given. Similarly, if seizures are likely to occur, there is a risk of aspiration and the charcoal should be avoided. Additionally, if there is reduced gastrointestinal motility, there is a risk of obstruction, so activated charcoal should not be used in such cases.
Activated charcoal is effective in treating overdose with various drugs and toxins, including aspirin, paracetamol, barbiturates, tricyclic antidepressants, digoxin, amphetamines, morphine, cocaine, and phenothiazines. However, it is ineffective in treating overdose with substances such as iron, lithium, boric acid, cyanide, ethanol, ethylene glycol, methanol, malathion, DDT, carbamate, hydrocarbon, strong acids, or alkalis.
There are some potential adverse effects associated with activated charcoal. These include nausea and vomiting, diarrhea, constipation, bezoar formation (a mass of undigested material that can cause blockages), bowel obstruction, pulmonary aspiration (inhaling the charcoal into the lungs), and impaired absorption of oral medications or antidotes.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 19
Incorrect
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A 28 year old male is brought into the emergency department in a comatose state with suspected poisoning. An arterial blood gas sample is taken. The results are shown below:
pH 7.22
pO2 12.5 kpa
pCO2 5.9 kpa
Bicarbonate 14 mmol/l
Chloride 98 mmol/l
Potassium 6.1 mmol/l
Sodium 136 mmol/l
Overdose or poisoning with which of the following typically leads to this type of acid base disturbance?Your Answer:
Correct Answer: Aspirin
Explanation:Salicylate poisoning often leads to a metabolic acidosis characterized by a high anion gap. The patient in question is experiencing this type of acid-base disturbance. This particular acid-base imbalance is typically seen in cases of poisoning with substances such as glycols (ethylene and propylene), salicylates (aspirin), paracetamol, methanol, isoniazid, and paraldehyde.
Further Reading:
Arterial blood gases (ABG) are an important diagnostic tool used to assess a patient’s acid-base status and respiratory function. When obtaining an ABG sample, it is crucial to prioritize safety measures to minimize the risk of infection and harm to the patient. This includes performing hand hygiene before and after the procedure, wearing gloves and protective equipment, disinfecting the puncture site with alcohol, using safety needles when available, and properly disposing of equipment in sharps bins and contaminated waste bins.
To reduce the risk of harm to the patient, it is important to test for collateral circulation using the modified Allen test for radial artery puncture. Additionally, it is essential to inquire about any occlusive vascular conditions or anticoagulation therapy that may affect the procedure. The puncture site should be checked for signs of infection, injury, or previous surgery. After the test, pressure should be applied to the puncture site or the patient should be advised to apply pressure for at least 5 minutes to prevent bleeding.
Interpreting ABG results requires a systematic approach. The core set of results obtained from a blood gas analyser includes the partial pressures of oxygen and carbon dioxide, pH, bicarbonate concentration, and base excess. These values are used to assess the patient’s acid-base status.
The pH value indicates whether the patient is in acidosis, alkalosis, or within the normal range. A pH less than 7.35 indicates acidosis, while a pH greater than 7.45 indicates alkalosis.
The respiratory system is assessed by looking at the partial pressure of carbon dioxide (pCO2). An elevated pCO2 contributes to acidosis, while a low pCO2 contributes to alkalosis.
The metabolic aspect is assessed by looking at the bicarbonate (HCO3-) level and the base excess. A high bicarbonate concentration and base excess indicate alkalosis, while a low bicarbonate concentration and base excess indicate acidosis.
Analyzing the pCO2 and base excess values can help determine the primary disturbance and whether compensation is occurring. For example, a respiratory acidosis (elevated pCO2) may be accompanied by metabolic alkalosis (elevated base excess) as a compensatory response.
The anion gap is another important parameter that can help determine the cause of acidosis. It is calculated by subtracting the sum of chloride and bicarbonate from the sum of sodium and potassium.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 20
Incorrect
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A 25-year-old woman with a previous history of depression is admitted to the emergency department following an overdose of amitriptyline tablets. The patient displays notable signs of toxicity, prompting the administration of intravenous sodium bicarbonate. What is the objective of this treatment?
Your Answer:
Correct Answer: Serum pH 7.45 to 7.55
Explanation:Sodium bicarbonate is used to treat severe TCA toxicity by reducing the risk of seizures and arrhythmia. The goal is to increase the serum pH to a range of 7.45 to 7.55 through alkalinisation.
Further Reading:
Tricyclic antidepressant (TCA) overdose is a common occurrence in emergency departments, with drugs like amitriptyline and dosulepin being particularly dangerous. TCAs work by inhibiting the reuptake of norepinephrine and serotonin in the central nervous system. In cases of toxicity, TCAs block various receptors, including alpha-adrenergic, histaminic, muscarinic, and serotonin receptors. This can lead to symptoms such as hypotension, altered mental state, signs of anticholinergic toxicity, and serotonin receptor effects.
TCAs primarily cause cardiac toxicity by blocking sodium and potassium channels. This can result in a slowing of the action potential, prolongation of the QRS complex, and bradycardia. However, the blockade of muscarinic receptors also leads to tachycardia in TCA overdose. QT prolongation and Torsades de Pointes can occur due to potassium channel blockade. TCAs can also have a toxic effect on the myocardium, causing decreased cardiac contractility and hypotension.
Early symptoms of TCA overdose are related to their anticholinergic properties and may include dry mouth, pyrexia, dilated pupils, agitation, sinus tachycardia, blurred vision, flushed skin, tremor, and confusion. Severe poisoning can lead to arrhythmias, seizures, metabolic acidosis, and coma. ECG changes commonly seen in TCA overdose include sinus tachycardia, widening of the QRS complex, prolongation of the QT interval, and an R/S ratio >0.7 in lead aVR.
Management of TCA overdose involves ensuring a patent airway, administering activated charcoal if ingestion occurred within 1 hour and the airway is intact, and considering gastric lavage for life-threatening cases within 1 hour of ingestion. Serial ECGs and blood gas analysis are important for monitoring. Intravenous fluids and correction of hypoxia are the first-line therapies. IV sodium bicarbonate is used to treat haemodynamic instability caused by TCA overdose, and benzodiazepines are the treatment of choice for seizure control. Other treatments that may be considered include glucagon, magnesium sulfate, and intravenous lipid emulsion.
There are certain things to avoid in TCA overdose, such as anti-arrhythmics like quinidine and flecainide, as they can prolonged depolarization.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 21
Incorrect
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You conduct a medication review on a 68-year-old man with a history of angina. He is currently prescribed 10 mg bisoprolol once daily and GTN spray as needed. However, he continues to experience symptoms.
Which ONE medication should be avoided in this patient?Your Answer:
Correct Answer: Verapamil
Explanation:Beta-blockers, like bisoprolol, and verapamil have a strong negative effect on the force of ventricular contraction. When these medications are taken together, they can significantly reduce ventricular contraction and lead to a slow heart rate, known as bradycardia. Additionally, the risk of developing AV block is increased. In certain situations, this combination can result in severe low blood pressure or even a complete absence of heart rhythm, known as asystole. Therefore, it is important to avoid using these medications together to prevent these potentially dangerous effects.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 22
Incorrect
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A 35-year-old woman with a history of heavy menstrual bleeding has ingested an excessive amount of ferrous sulfate.
What are the possible antidotes that can be administered in cases of iron salt poisoning?Your Answer:
Correct Answer: Desferrioxamine
Explanation:There are various specific remedies available for different types of poisons and overdoses. The following list provides an outline of some of these antidotes:
Poison: Benzodiazepines
Antidote: FlumazenilPoison: Beta-blockers
Antidotes: Atropine, Glucagon, InsulinPoison: Carbon monoxide
Antidote: OxygenPoison: Cyanide
Antidotes: Hydroxocobalamin, Sodium nitrite, Sodium thiosulphatePoison: Ethylene glycol
Antidotes: Ethanol, FomepizolePoison: Heparin
Antidote: Protamine sulphatePoison: Iron salts
Antidote: DesferrioxaminePoison: Isoniazid
Antidote: PyridoxinePoison: Methanol
Antidotes: Ethanol, FomepizolePoison: Opioids
Antidote: NaloxonePoison: Organophosphates
Antidotes: Atropine, PralidoximePoison: Paracetamol
Antidotes: Acetylcysteine, MethioninePoison: Sulphonylureas
Antidotes: Glucose, OctreotidePoison: Thallium
Antidote: Prussian bluePoison: Warfarin
Antidote: Vitamin K, Fresh frozen plasma (FFP)By utilizing these specific antidotes, medical professionals can effectively counteract the harmful effects of various poisons and overdoses.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 23
Incorrect
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A 25-year-old man has had discoloured teeth since taking a medication in his youth. Upon examination, visible greyish-brown horizontal stripes can be observed across all of his teeth.
Which SINGLE medication is most likely responsible for this?Your Answer:
Correct Answer: Doxycycline
Explanation:Tetracycline antibiotics, such as tetracycline and doxycycline, have the potential to cause staining on permanent teeth while they are still forming beneath the gum line. This staining occurs when the drug becomes calcified within the tooth during its development. It is important to note that children are vulnerable to tetracycline-related tooth staining until approximately the age of 8. Additionally, pregnant women should avoid taking tetracycline as it can affect the development of teeth in the unborn child.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 24
Incorrect
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A 68 year old male with dementia is brought into the emergency department by his daughter due to a sudden decline in cognitive function over the past week. The daughter suspects that the patient's medication may have been altered recently. She presents you with the tablets she discovered in the patient's room. Which medication is most likely responsible for the decline in the patient's cognitive abilities?
Your Answer:
Correct Answer: Oxybutynin
Explanation:Anticholinergic drugs have been found to worsen cognitive impairment in individuals with dementia. Certain commonly prescribed medications are associated with a higher anticholinergic burden, which can lead to increased cognitive decline. Examples of drugs with high anticholinergic potency include tricyclic antidepressants like amitriptyline hydrochloride, paroxetine, first-generation antihistamines such as chlorpheniramine maleate and promethazine hydrochloride, certain antipsychotics like olanzapine, clozapine, and quetiapine, urinary antispasmodics like solifenacin, oxybutynin, and tolterodine, and antimuscarinics like ipratropium, tiotropium, atropine, and cyclopentolate. However, it’s important to note that rivastigmine and memantine are recommended as first-line treatments for Alzheimer’s and DLB, while haloperidol, despite being an antipsychotic, has low anticholinergic potency.
Further Reading:
Dementia is a progressive and irreversible clinical syndrome characterized by cognitive and behavioral symptoms. These symptoms include memory loss, impaired reasoning and communication, personality changes, and reduced ability to carry out daily activities. The decline in cognition affects multiple domains of intellectual functioning and is not solely due to normal aging.
To diagnose dementia, a person must have impairment in at least two cognitive domains that significantly impact their daily activities. This impairment cannot be explained by delirium or other major psychiatric disorders. Early-onset dementia refers to dementia that develops before the age of 65.
The most common cause of dementia is Alzheimer’s disease, accounting for 50-75% of cases. Other causes include vascular dementia, dementia with Lewy bodies, and frontotemporal dementia. Less common causes include Parkinson’s disease dementia, Huntington’s disease, prion disease, and metabolic and endocrine disorders.
There are several risk factors for dementia, including age, mild cognitive impairment, genetic predisposition, excess alcohol intake, head injury, depression, learning difficulties, diabetes, obesity, hypertension, smoking, Parkinson’s disease, low social engagement, low physical activity, low educational attainment, hearing impairment, and air pollution.
Assessment of dementia involves taking a history from the patient and ideally a family member or close friend. The person’s current level of cognition and functional capabilities should be compared to their baseline level. Physical examination, blood tests, and cognitive assessment tools can also aid in the diagnosis.
Differential diagnosis for dementia includes normal age-related memory changes, mild cognitive impairment, depression, delirium, vitamin deficiencies, hypothyroidism, adverse drug effects, normal pressure hydrocephalus, and sensory deficits.
Management of dementia involves a multi-disciplinary approach that includes non-pharmacological and pharmacological measures. Non-pharmacological interventions may include driving assessment, modifiable risk factor management, and non-pharmacological therapies to promote cognition and independence. Drug treatments for dementia should be initiated by specialists and may include acetylcholinesterase inhibitors, memantine, and antipsychotics in certain cases.
In summary, dementia is a progressive and irreversible syndrome characterized by cognitive and behavioral symptoms. It has various causes and risk factors, and its management involves a multi-disciplinary approach.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 25
Incorrect
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A 35-year-old woman is given a medication for a medical ailment during the 4th and 5th month of her pregnancy. As a result, the unborn baby has experienced reduced blood flow and a condition known as oligohydramnios sequence.
Which of the listed medications is the most probable cause of these abnormalities?Your Answer:
Correct Answer: Ramipril
Explanation:During the second and third trimesters of pregnancy, exposure to ACE inhibitors can lead to hypoperfusion, renal failure, and the oligohydramnios sequence. This sequence refers to the abnormal physical appearance of a fetus or newborn due to low levels of amniotic fluid in the uterus. It is also associated with malformations of the patient ductus arteriosus and aortic arch. These defects are believed to be caused by the inhibitory effects of ACE inhibitors on the renin-angiotensin-aldosterone system. To avoid these risks, it is recommended to discontinue ACE inhibitors before the second trimester.
Here is a list outlining the most commonly encountered drugs that have adverse effects during pregnancy:
Drug: ACE inhibitors
Adverse effects: If given in the second and third trimesters, can cause hypoperfusion, renal failure, and the oligohydramnios sequence.Drug: Aminoglycosides
Adverse effects: Ototoxicity (damage to the ear) and deafness.Drug: Aspirin
Adverse effects: High doses can cause first trimester abortions, delayed onset labor, premature closure of the fetal ductus arteriosus, and fetal kernicterus. Low doses (e.g. 75 mg) have no significant associated risk.Drug: Benzodiazepines
Adverse effects: When given late in pregnancy, respiratory depression and a neonatal withdrawal syndrome can occur.Drug: Calcium-channel blockers
Adverse effects: If given in the first trimester, can cause phalangeal abnormalities. If given in the second and third trimesters, can cause fetal growth retardation. -
This question is part of the following fields:
- Pharmacology & Poisoning
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Question 26
Incorrect
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A 45 year old female presents to the emergency department with a 4 day history of persistent vomiting, severe diarrhea, and loss of appetite. The patient reports feeling extremely weak. A peripheral cannula is inserted and blood samples are collected. The initial laboratory results are as follows:
Sodium (Na+): 134 mmol/L
Potassium (K+): 2.4 mmol/L
Urea (Ur): 8.2 mmol/L
Creatinine (Cr): 115 umol/L
Based on these findings, which of the following additional tests should be prioritized and requested?Your Answer:
Correct Answer: Magnesium
Explanation:Hypomagnesaemia frequently occurs alongside hypokalaemia. It is important to note that potassium levels may not improve with supplementation until the magnesium deficiency is addressed.
Further Reading:
Vasoactive drugs can be classified into three categories: inotropes, vasopressors, and unclassified. Inotropes are drugs that alter the force of muscular contraction, particularly in the heart. They primarily stimulate adrenergic receptors and increase myocardial contractility. Commonly used inotropes include adrenaline, dobutamine, dopamine, isoprenaline, and ephedrine.
Vasopressors, on the other hand, increase systemic vascular resistance (SVR) by stimulating alpha-1 receptors, causing vasoconstriction. This leads to an increase in blood pressure. Commonly used vasopressors include norepinephrine, metaraminol, phenylephrine, and vasopressin.
Electrolytes, such as potassium, are essential for proper bodily function. Solutions containing potassium are often given to patients to prevent or treat hypokalemia (low potassium levels). However, administering too much potassium can lead to hyperkalemia (high potassium levels), which can cause dangerous arrhythmias. It is important to monitor potassium levels and administer it at a controlled rate to avoid complications.
Hyperkalemia can be caused by various factors, including excessive potassium intake, decreased renal excretion, endocrine disorders, certain medications, metabolic acidosis, tissue destruction, and massive blood transfusion. It can present with cardiovascular, respiratory, gastrointestinal, and neuromuscular symptoms. ECG changes, such as tall tented T-waves, prolonged PR interval, flat P-waves, widened QRS complex, and sine wave, are also characteristic of hyperkalemia.
In summary, vasoactive drugs can be categorized as inotropes, vasopressors, or unclassified. Inotropes increase myocardial contractility, while vasopressors increase systemic vascular resistance. Electrolytes, particularly potassium, are important for bodily function, but administering too much can lead to hyperkalemia. Monitoring potassium levels and ECG changes is crucial in managing hyperkalemia.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 27
Incorrect
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You assess a 70-year-old woman who is admitted to the clinical decision unit (CDU) after a fall last night. She has a significant cardiac history, having experienced a heart attack 3 years ago and is currently being evaluated for cardiac arrhythmias. She occasionally experiences episodes of angina. Upon reviewing her medication list, you identify one specific medication that should be discontinued immediately.
Your Answer:
Correct Answer: Verapamil
Explanation:Verapamil is a type of calcium-channel blocker that is commonly used to treat irregular heart rhythms and chest pain. It is important to note that verapamil should not be taken at the same time as beta-blockers like atenolol. This is because when these medications are combined, they can have a negative impact on the heart’s ability to contract and its heart rate. This can lead to low blood pressure, slow heart rate, problems with the electrical signals in the heart, heart failure, and even a pause in the heart’s normal rhythm. However, the other medications mentioned in this question can be safely used together with beta-blockers.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 28
Incorrect
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A 42-year-old man has recently taken an antibiotic for a skin infection. He has been experiencing palpitations and had an ECG performed, which shows the presence of new QT prolongation.
Which of the following antibiotics is he most likely to have taken?Your Answer:
Correct Answer: Erythromycin
Explanation:Prolongation of the QT interval can lead to a dangerous ventricular arrhythmia called torsades de pointes, which can result in sudden cardiac death. There are several commonly used medications that are known to cause QT prolongation.
Low levels of potassium (hypokalaemia) and magnesium (hypomagnesaemia) can increase the risk of QT prolongation. For example, diuretics can interact with QT-prolonging drugs by causing hypokalaemia.
The QT interval varies with heart rate, and formulas are used to correct the QT interval for heart rate. Once corrected, it is referred to as the QTc interval. The QTc interval is typically reported on the ECG printout. A normal QTc interval is less than 440 ms.
If the QTc interval is greater than 440 ms but less than 500 ms, it is considered borderline. Although there may be some variation in the literature, a QTc interval within these values is generally considered borderline prolonged. In such cases, it is important to consider reducing the dose of QT-prolonging drugs or switching to an alternative medication that does not prolong the QT interval.
A prolonged QTc interval exceeding 500 ms is clinically significant and is likely to increase the risk of arrhythmia. Any medications that prolong the QT interval should be reviewed immediately.
Here are some commonly encountered drugs that are known to prolong the QT interval:
Antimicrobials:
– Erythromycin
– Clarithromycin
– Moxifloxacin
– Fluconazole
– KetoconazoleAntiarrhythmics:
– Dronedarone
– Sotalol
– Quinidine
– Amiodarone
– FlecainideAntipsychotics:
– Risperidone
– Fluphenazine
– Haloperidol
– Pimozide
– Chlorpromazine
– Quetiapine
– ClozapineAntidepressants:
– Citalopram/escitalopram
– Amitriptyline
– Clomipramine
– Dosulepin
– Doxepin
– Imipramine
– LofepramineAntiemetics:
– Domperidone
– Droperidol
– Ondansetron/GranisetronOthers:
– Methadone
– Protein kinase inhibitors (e.g. sunitinib) -
This question is part of the following fields:
- Pharmacology & Poisoning
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Question 29
Incorrect
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A 17 year old girl is admitted to the emergency department following a suicide attempt. The patient consumed a container of expired insecticide and reports feeling unwell shortly after ingestion, resulting in two episodes of vomiting. After consulting toxbase, it is determined that the product is an organophosphate.
Which of the following is an established antidote for organophosphate poisoning?Your Answer:
Correct Answer: Atropine
Explanation:Atropine and pralidoxime are both considered antidotes for treating organophosphate poisoning. Organophosphates work by inhibiting acetylcholinesterase at nerve synapses. In addition to providing supportive care and administering antidotes, it is important to decontaminate patients as part of their treatment plan for organophosphate poisoning.
While both atropine and pralidoxime are recognized as antidotes, pralidoxime is not commonly used. Atropine works by competing with acetylcholine at the muscarinic receptors. On the other hand, pralidoxime helps reactivate acetylcholinesterase-organophosphate complexes that have not lost an alkyl side chain, known as non-aged complexes. However, pralidoxime is not effective against organophosphates that have already formed or rapidly form aged acetylcholinesterase complexes. The evidence regarding the effectiveness of pralidoxime is conflicting.
Further Reading:
Chemical incidents can occur as a result of leaks, spills, explosions, fires, terrorism, or the use of chemicals during wars. Industrial sites that use chemicals are required to conduct risk assessments and have accident plans in place for such incidents. Health services are responsible for decontamination, unless mass casualties are involved, and all acute health trusts must have major incident plans in place.
When responding to a chemical incident, hospitals prioritize containment of the incident and prevention of secondary contamination, triage with basic first aid, decontamination if not done at the scene, recognition and management of toxidromes (symptoms caused by exposure to specific toxins), appropriate supportive or antidotal treatment, transfer to definitive treatment, a safe end to the hospital response, and continuation of business after the event.
To obtain advice when dealing with chemical incidents, the two main bodies are Toxbase and the National Poisons Information Service. Signage on containers carrying chemicals and material safety data sheets (MSDS) accompanying chemicals also provide information on the chemical contents and their hazards.
Contamination in chemical incidents can occur in three phases: primary contamination from the initial incident, secondary contamination spread via contaminated people leaving the initial scene, and tertiary contamination spread to the environment, including becoming airborne and waterborne. The ideal personal protective equipment (PPE) for chemical incidents is an all-in-one chemical-resistant overall with integral head/visor and hands/feet worn with a mask, gloves, and boots.
Decontamination of contaminated individuals involves the removal and disposal of contaminated clothing, followed by either dry or wet decontamination. Dry decontamination is suitable for patients contaminated with non-caustic chemicals and involves blotting and rubbing exposed skin gently with dry absorbent material. Wet decontamination is suitable for patients contaminated with caustic chemicals and involves a warm water shower while cleaning the body with simple detergent.
After decontamination, the focus shifts to assessing the extent of any possible poisoning and managing it. The patient’s history should establish the chemical the patient was exposed to, the volume and concentration of the chemical, the route of exposure, any protective measures in place, and any treatment given. Most chemical poisonings require supportive care using standard resuscitation principles, while some chemicals have specific antidotes. Identifying toxidromes can be useful in guiding treatment, and specific antidotes may be administered accordingly.
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This question is part of the following fields:
- Pharmacology & Poisoning
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Question 30
Incorrect
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A 30-year-old man has ingested an excessive amount of paracetamol. He consumed the overdose 12 hours ago and is unsure of the number of tablets he has taken.
Which of the following substances can be utilized as an antidote for paracetamol overdose?Your Answer:
Correct Answer: Methionine
Explanation:The primary treatment for paracetamol overdose is acetylcysteine. Acetylcysteine is an extremely effective antidote, but its effectiveness decreases quickly if administered more than a few hours after a significant ingestion. Ingestions that exceed 75 mg/kg are considered to be significant.
For patients who decline treatment, methionine is a helpful alternative. It is taken orally in a dosage of 2.5 g every 4 hours, with a total dose of 10 g.
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This question is part of the following fields:
- Pharmacology & Poisoning
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