Complications in Anesthesia Practice Questions

Q: Intra-arterial thiopentone injection leads to?

Ischemia. ***Ischemia*** - Intra-arterial injection of **thiopentone** causes severe **vasospasm** and **precipitation of barbiturate crystals** in the arterial lumen, leading to **thrombosis** and **obstruction** of blood flow. - This results in acute **ischemia** distal to the injection site, which can progress to **gangrene** and **limb loss** if not promptly managed. *Vasodilatation* - **Thiopentone** is a potent **vasoconstrictor** when injected intra-arterially due to its highly alkaline pH and direct irritation of the vascular endothelium. - Therefore, it causes **vasospasm**, not vasodilatation, which is the opposite effect and a key mechanism of the ensuing ischemia. *Vomiting* - **Vomiting** is not a characteristic or direct consequence of intra-arterial thiopentone injection; it is more commonly associated with systemic effects of some medications or with stimulation of the **chemoreceptor trigger zone**. - The adverse effects of intra-arterial thiopentone are primarily localized to the affected limb vasculature. *Hypertension* - While thiopentone can cause transient hypotension when administered intravenously as an anesthetic, **intra-arterial injection** does not typically cause systemic **hypertension**. - The primary local effect is **vasoconstriction** and **ischemia** in the injected limb, not a systemic rise in blood pressure.

Q: Which of the following is NOT a feature of Propofol infusion syndrome?

Features are nausea and vomiting. ***Features are nausea and vomiting*** - **Nausea and vomiting** are common side effects of many medications, including propofol, but they are not specific features of **Propofol Infusion Syndrome (PRIS)**. - PRIS is a rare but severe complication characterized by metabolic and cardiac dysfunction, not gastrointestinal upset. *Occurs with infusion of propofol for 48 hours or longer* - **PRIS** typically manifests after prolonged infusions of propofol, usually **48 hours or more**, especially at high doses. - This time frame allows for the accumulation of propofol metabolites that contribute to mitochondrial dysfunction. *Occurs in critically ill patients* - **PRIS** is predominantly observed in **critically ill patients**, particularly those with severe head injury, sepsis, or burns, who are receiving prolonged high-dose propofol. - These patients often have pre-existing metabolic stress and reduced compensatory mechanisms, making them more susceptible. *Features are cardiomyopathy, hepatomegaly* - **Cardiomyopathy**, leading to **cardiac failure**, is a prominent and often fatal feature of **PRIS**. - **Hepatomegaly**, resulting from hepatic dysfunction and fat accumulation, is also commonly observed in patients with PRIS.

Q: Which of the following anesthetic agents is not associated with hepatotoxicity?

Propofol. ***Propofol*** - **Propofol** is an intravenous anesthetic agent not typically associated with significant hepatotoxicity. - It is **metabolized in the liver** and excreted renally, but does not cause acute liver injury as seen with some inhalational agents. *Halothane* - **Halothane** is a known cause of **halothane hepatitis**, a severe and sometimes fatal form of liver injury. - This reaction involves an immune-mediated response against **trifluoroacetylated liver proteins**. *Chloroform* - **Chloroform** was historically used as an anesthetic but was largely abandoned due to its significant **hepatotoxic** and nephrotoxic effects. - It causes direct toxic injury to hepatocytes, leading to **centrilobular necrosis**. *Ether* - While *diethyl ether* is largely obsolete in modern anesthesia, prolonged exposure or high concentrations can lead to some degree of **liver dysfunction**. - However, its hepatotoxic potential is generally considered less severe than halothane or chloroform.

Q: Which of the following statements about malignant hyperthermia is false?

Most common cause is succinylcholine. ***Most common cause is succinylcholine*** - While **succinylcholine** can trigger malignant hyperthermia, it is not the *most common cause* of the condition itself. **Volatile anesthetics** are more frequently implicated. - Malignant hyperthermia is a **genetic disorder** of skeletal muscle, not primarily caused by a drug. *Dantrolene is the treatment of choice* - This statement is **true** because **dantrolene** is the specific and highly effective treatment for malignant hyperthermia, working by blocking calcium release from the sarcoplasmic reticulum. - Its rapid administration is crucial for reversing the hypermetabolic crisis caused by uncontrolled calcium efflux. *End tidal CO2 is increased during an episode* - This statement is **true**. The hallmark of malignant hyperthermia is excessive muscle metabolism, leading to increased **carbon dioxide production** and a significant rise in **end-tidal CO2**. - This rapid and unexplained increase in end-tidal CO2 is often the earliest and most sensitive indicator of an MH episode. *Tachycardia occurs* - This statement is **true**. The hypermetabolic state in malignant hyperthermia leads to increased oxygen consumption, heat production, and metabolic acidosis, all of which contribute to a compensatory **tachycardia**. - **Tachycardia** is one of the early and common clinical signs, alongside tachypnea and muscle rigidity.

Q: What is the best immediate management for a patient experiencing anaphylaxis during surgery?

Give adrenaline. ***Give adrenaline*** - **Adrenaline (epinephrine)** is the first-line and most critical treatment for anaphylaxis due to its potent **vasoconstrictive** and **bronchodilatory** effects. - It rapidly reverses **hypotension**, **bronchospasm**, and other life-threatening symptoms associated with the systemic allergic reaction. *Give atropine* - **Atropine** is primarily used to treat **bradycardia** and would not address the widespread vasodilation and bronchoconstriction characteristic of anaphylaxis. - While anaphylaxis can sometimes present with bradycardia, the primary circulatory collapse is due to **vasodilation**, which atropine does not counteract. *Increase level of anesthesia* - Increasing the level of anesthesia might **depress myocardial function** and exacerbate the **hypotension** already caused by anaphylaxis, further compromising the patient. - Anesthesia is not a treatment for an anaphylactic reaction, which requires specific pharmacological interventions to stabilize the patient. *Ask the surgeon to stop the surgery* - While it may be necessary to pause or stop the surgery, this is **not the immediate medical management** for a life-threatening anaphylactic reaction. - The priority is to administer **life-saving medication** like adrenaline, after which decisions about continuing or stopping surgery can be made.

Q: A patient developed fulminant hepatitis after receiving inhalational anesthesia with a drug to which he had been previously exposed. Which drug is most likely responsible?

Halothane. ***Halothane*** - **Halothane hepatitis** is a rare but severe complication, especially upon re-exposure, due to the formation of reactive metabolites that trigger an immune response against liver cells. - The disease can range from mild liver enzyme elevation to **fulminant hepatic failure** and death. *N2O* - **Nitrous oxide** primarily causes megaloblastic anemia and neurotoxicity with prolonged exposure by interfering with vitamin B12 metabolism, not hepatotoxicity. - It works by inhibiting methionine synthase, but does not cause dose-dependent or idiosyncratic liver damage associated with fulminant hepatitis. *Enflurane* - While enflurane can rarely cause **hepatotoxicity**, it is significantly less common and less severe than with halothane. - It is more frequently associated with **nephrotoxicity** due to fluoride ion release, especially at high doses or prolonged exposure. *Isoflurane* - **Isoflurane** is one of the safest modern inhalational anesthetics with a very low incidence of hepatotoxicity due to minimal metabolism and conversion to toxic metabolites. - It is rarely implicated in liver injury, making fulminant hepatitis highly unlikely.

Q: Calcium homeostasis disturbance is the predominant pathophysiological mechanism in

Malignant hyperthermia. ***Malignant hyperthermia*** - Malignant hyperthermia is caused by a genetic defect in the **ryanodine receptor (RYR1)** in skeletal muscle, leading to an uncontrolled release of **intracellular calcium** from the sarcoplasmic reticulum. - This excessive calcium release results in sustained muscle contraction, increased metabolism, and a rapid rise in body temperature. *Duchenne Muscular Dystrophy (DMD)* - DMD is primarily caused by a mutation in the **dystrophin gene**, which leads to the absence or severe deficiency of the **dystrophin protein**. - This deficiency results in muscle fiber fragility, cycles of degeneration and regeneration, and eventual replacement of muscle with fibrous and fatty tissue, rather than a primary calcium homeostasis disturbance. *Limb Girdle Muscular Dystrophy* - This group of disorders is characterized by progressive weakness and wasting of muscles, primarily affecting the **shoulders and hips**. - The pathophysiology involves genetic defects in various proteins that are crucial for muscle function and integrity, such as **sarcoglycans** or **calpain-3**, not primarily calcium dysregulation. *Tibial Muscular Dystrophy* - Tibial muscular dystrophy is a rare, late-onset disorder characterized by progressive weakness of the **anterior tibial muscles**. - It is typically caused by mutations in the **TTN gene**, encoding for the protein **titin**, which plays a vital role in muscle elasticity and structural integrity, rather than a primary calcium imbalance.

Q: What is the consequence of using the anesthetic Trilene in conjunction with sodium bicarbonate?

Renal damage. ***Renal damage*** - The combination of **Trilene (trichloroethylene)** and **sodium bicarbonate** can lead to the formation of **dichloroacetylene**, a nephrotoxic compound. - This compound causes **acute tubular necrosis** and significant renal dysfunction, leading to irreversible kidney damage. *ARDS* - **Acute Respiratory Distress Syndrome (ARDS)** is typically associated with direct lung injury or severe systemic inflammatory responses, not directly with this specific drug interaction. - While anesthesia can affect respiratory function, this particular combination does not primarily lead to ARDS. *Myocardial depression* - Many anesthetics can cause **myocardial depression**, but the specific interaction between Trilene and sodium bicarbonate is not primarily known for this effect. - The primary concern with this combination is **nephrotoxicity**, not direct cardiac suppression. *Hepatitis* - Drug-induced **hepatitis** is a known risk with various medications, but not specifically with the combination of Trilene and sodium bicarbonate. - While some halogenated anesthetics can rarely cause liver injury, the formation of dichloroacetylene primarily targets the kidneys.

Q: A 56-year-old man undergoes a left upper lobectomy. An epidural catheter is inserted for postoperative pain relief. Ninety minutes after the first dose of epidural morphine, the patient complains of itching and becomes increasingly somnolent. Blood gas measurement reveals the following: pH 7.24; PaCO2 58; PaO2 100; HCO3- 28. What is the most appropriate initial therapy?

Intravenous naloxone. ***Intravenous naloxone*** - The patient exhibits classic signs of **opioid overdose** including **somnolence**, **respiratory depression** (indicated by pH 7.24 and PaCO2 58), and **itching**, occurring after epidural morphine administration. - **Naloxone** is a rapidly acting **opioid antagonist** that reverses these effects, and the intravenous route provides the quickest systemic onset for emergency situations. *Endotracheal intubation (if airway is compromised)* - While intubation may be necessary if the patient's respiratory status deteriorates further and they cannot maintain their airway, it is not the *initial* therapy for opioid overdose reversal. - The primary goal is to reverse the opioid effects with an antagonist first to see if respiratory drive improves, potentially avoiding intubation. *Intramuscular diphenhydramine (for itching)* - **Diphenhydramine** only addresses the **symptom of itching** and does not reverse the life-threatening respiratory depression or somnolence caused by opioid overdose. - Treating only a side effect while ignoring the underlying cause is inappropriate in this critical situation. *Epidural naloxone (for localized effect)* - Epidural naloxone would primarily act at the spinal cord level to reverse localized opioid effects without having significant systemic impact on **respiratory depression** or **somnolence**. - For systemic opioid toxicity, **intravenous naloxone** is required for rapid brain penetration and reversal of central respiratory depression.

Q: Malignant hyperthermia is most common with:

Succinylcholine. ***Succinylcholine*** - **Malignant hyperthermia** is a life-threatening pharmacogenetic disorder triggered by certain anesthetic agents, predominantly **succinylcholine** and volatile inhalational anesthetics. - Succinylcholine, a **depolarizing neuromuscular blocker**, can induce a massive release of calcium from the sarcoplasmic reticulum in susceptible individuals, leading to sustained muscle contraction and hypermetabolism. *Gallamine* - **Gallamine** is a non-depolarizing neuromuscular blocker and is not known to be a trigger for malignant hyperthermia. - Non-depolarizing neuromuscular blockers work by competitively blocking acetylcholine receptors at the neuromuscular junction without causing depolarization, and thus do not typically induce the uncontrolled calcium release seen in malignant hyperthermia. *Dantrolene* - **Dantrolene** is the specific antidote used to treat malignant hyperthermia; it is not a trigger. - It works by directly interfering with calcium release from the sarcoplasmic reticulum in skeletal muscle, thereby reversing the pathological process of malignant hyperthermia. *Ketamine* - **Ketamine** is a dissociative anesthetic that acts as an NMDA receptor antagonist and is generally considered safe for use in patients susceptible to malignant hyperthermia. - While it can cause an increase in heart rate and blood pressure, it does not trigger the underlying pathophysiology of uncontrolled calcium release characteristic of malignant hyperthermia.

Question 1

Intra-arterial thiopentone injection leads to?

Accepted Answer

Ischemia

Answer

Vasodilatation

Answer

Vomiting

Answer

Hypertension

Question 2

Which of the following is NOT a feature of Propofol infusion syndrome?

Accepted Answer

Features are nausea and vomiting

Answer

Occurs with infusion of propofol for 48 hours or longer

Answer

Occurs in critically ill patients

Answer

Features are cardiomyopathy, hepatomegaly

Question 3

Which of the following anesthetic agents is not associated with hepatotoxicity?

Accepted Answer

Propofol

Answer

Halothane

Answer

Chloroform

Answer

Ether

Question 4

Which of the following statements about malignant hyperthermia is false?

Accepted Answer

Most common cause is succinylcholine

Answer

End tidal CO2 is increased during an episode

Answer

Dantrolene is the treatment of choice

Answer

Tachycardia occurs

Question 5

What is the best immediate management for a patient experiencing anaphylaxis during surgery?

Accepted Answer

Give adrenaline

Answer

Give atropine

Answer

Increase level of anesthesia

Answer

Ask the surgeon to stop the surgery

Question 6

A patient developed fulminant hepatitis after receiving inhalational anesthesia with a drug to which he had been previously exposed. Which drug is most likely responsible?

Accepted Answer

Halothane

Answer

Enflurane

Answer

Isoflurane

Answer

N2O

Question 7

Calcium homeostasis disturbance is the predominant pathophysiological mechanism in

Accepted Answer

Malignant hyperthermia

Answer

Duchenne Muscular Dystrophy (DMD)

Answer

Limb Girdle Muscular Dystrophy

Answer

Tibial Muscular Dystrophy

Question 8

What is the consequence of using the anesthetic Trilene in conjunction with sodium bicarbonate?

Accepted Answer

Renal damage

Answer

Myocardial depression

Answer

Hepatitis

Answer

ARDS

Question 9

A 56-year-old man undergoes a left upper lobectomy. An epidural catheter is inserted for postoperative pain relief. Ninety minutes after the first dose of epidural morphine, the patient complains of itching and becomes increasingly somnolent. Blood gas measurement reveals the following: pH 7.24; PaCO2 58; PaO2 100; HCO3- 28. What is the most appropriate initial therapy?

Accepted Answer

Intravenous naloxone

Answer

Endotracheal intubation (if airway is compromised)

Answer

Intramuscular diphenhydramine (for itching)

Answer

Epidural naloxone (for localized effect)

Question 10

Malignant hyperthermia is most common with:

Accepted Answer

Succinylcholine

Answer

Gallamine

Answer

Dantrolene

Answer

Ketamine

Complications in Anesthesia — MCQs

Complications in Anesthesia — MCQs

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