Complications in Anesthesia Practice Questions

Q: A child during anesthesia with halothane and succinylcholine develops severe stiffness of masseters. What is the most probable diagnosis?

Malignant hyperthermia. ***Malignant hyperthermia*** - **Masseter muscle rigidity** following exposure to **succinylcholine** and a **halogenated inhalational anesthetic** (like halothane) is a hallmark sign of malignant hyperthermia. - This inherited disorder results in uncontrolled **calcium release** from the sarcoplasmic reticulum in skeletal muscle, leading to hypermetabolism, severe muscle contraction, and a rapid rise in body temperature. *Halothane hepatitis* - This is an idiosyncratic liver injury that can occur hours to days after exposure to halothane, not an acute intraoperative event causing muscle stiffness. - Symptoms include elevated liver enzymes, jaundice, and often fever, but without the immediate muscle rigidity seen here. *Neuroleptic malignant syndrome* - This condition is associated with the use of **antipsychotic medications** and presents with muscle rigidity, fever, altered mental status, and autonomic instability. - It does not involve exposure to succinylcholine or inhalational anesthetics and has a slower onset, typically over days. *Anaphylaxis* - Anaphylaxis is a severe, acute allergic reaction characterized by **bronchospasm**, **hypotension**, **urticaria**, and angioedema. - While it can manifest rapidly during anesthesia, it does not typically cause severe, generalized muscle stiffness as the primary symptom.

Q: 30 year old lady was on the OT and during the mastoidectomy, after having inhalational anaesthesia, suddenly developed fever, increased heart rate, raised BP, acidosis and arrythmia. What is the next best intervention?

Dantrolene. ***Dantrolene*** - The patient's presentation with **fever**, **tachycardia**, **hypertension**, **acidosis**, and **arrhythmia** during inhalational anesthesia is highly indicative of **malignant hyperthermia**. - **Dantrolene** is the specific and most effective treatment for malignant hyperthermia as it acts by interfering with muscle contraction by blocking calcium release from the sarcoplasmic reticulum. *Antipyretics* - While the patient has a fever, **antipyretics** like paracetamol or NSAIDs are not sufficient to manage the rapidly rising core body temperature in malignant hyperthermia. - The fever is a symptom of severe metabolic dysregulation, and simple antipyresis does not address the underlying pathology. *Sodium bicarbonate* - The patient has acidosis, but **sodium bicarbonate** is used to correct metabolic acidosis by buffering excess acid only after the primary cause is addressed. - While it may be used as supportive care, it does not treat the underlying mechanism of malignant hyperthermia. *Procainamide* - **Procainamide** is an antiarrhythmic drug used to treat various arrhythmias but does not address the fundamental cause of the arrhythmias in malignant hyperthermia. - The arrhythmias in malignant hyperthermia are a consequence of severe metabolic derangements and hyperkalemia, which require dantrolene and supportive care to resolve.

Q: A 10-year old child is undergoing squint surgery. He suddenly developed increased heart rate, arrhythmia, high fever, metabolic and respiratory acidosis on arterial blood gases and elevation of end tidal CO2. Which of the following would be the first agent of choice in the management of this condition?

Dantrolene. ***Dantrolene*** - The constellation of **tachycardia**, **arrhythmia**, **high fever**, **acidosis**, and **elevated end-tidal CO2** during surgery strongly points to **malignant hyperthermia (MH)**. - **Dantrolene** is the specific and most effective direct-acting skeletal muscle relaxant that treats MH by reducing intracellular calcium release. *Procainamide* - **Procainamide** is an **antiarrhythmic drug** that could be used to manage some arrhythmias, but it does not address the underlying pathophysiology of malignant hyperthermia. - While arrhythmias are a symptom of MH, simply treating the arrhythmia without addressing the hypermetabolic state is insufficient and potentially dangerous. *Sodium bicarbonate* - **Sodium bicarbonate** is used to treat **metabolic acidosis**, which is a sign of MH, but it does not treat the root cause of the acidosis, which is the massive release of calcium in muscle cells. - While it can temporize the acid-base balance, it is not the primary treatment for the overall syndrome. *Paracetamol* - **Paracetamol** is an **antipyretic** and **analgesic** and would be completely ineffective in managing the rapid and severe temperature elevation seen in malignant hyperthermia. - Its mechanism of action does not address the massive heat production and hypermetabolism characteristic of MH.

Q: A patient presents with malignant hyperthermia and metabolic acidosis. Immediate treatment should be started with:

Intravenous Dantrolene. ***Intravenous Dantrolene*** - **Dantrolene** is the specific and primary treatment for **malignant hyperthermia** as it acts directly on the **ryanodine receptor** to inhibit calcium release from the sarcoplasmic reticulum, relaxing skeletal muscle. - Its prompt administration is crucial in reversing the life-threatening metabolic and physiological derangements associated with this condition, including **hyperthermia** and **metabolic acidosis**. *Intravenous fluids* - While **intravenous fluids** are important for maintaining hydration and supporting renal function in patients with **malignant hyperthermia**, they are a supportive measure, not the definitive treatment. - They primarily address complications like **dehydration** and **rhabdomyolysis**, but do not directly treat the underlying pathophysiology of excessive calcium release. *Sodium bicarbonate* - **Sodium bicarbonate** may be used to correct severe **metabolic acidosis**, which can be a consequence of **malignant hyperthermia**. - However, treating the acidosis without addressing the primary cause (malignant hyperthermia) by administering dantrolene is insufficient and will not stop the progression of the syndrome. *Paracetamol* - **Paracetamol (acetaminophen)** is an antipyretic often used for fever reduction, but it is entirely ineffective in treating the rapid and severe hyperthermia of **malignant hyperthermia**. - The temperature dysregulation in malignant hyperthermia is caused by uncontrolled muscle metabolism, not a response to typical antipyretics, and thus paracetamol would provide no therapeutic benefit.

Q: Drug used in treatment of malignant hyperthermia is

Dantrolene. ***Dantrolene*** - **Dantrolene** is a direct-acting **skeletal muscle relaxant** that works by preventing calcium release from the sarcoplasmic reticulum. - This mechanism effectively counteracts the excessive calcium efflux responsible for the sustained muscle contraction and hypermetabolic state in **malignant hyperthermia**. *Phenobarbitone* - **Phenobarbitone** is a barbiturate primarily used as an **anticonvulsant** and sedative-hypnotic. - It has no direct muscle relaxant properties or specific action to address the underlying pathophysiology of **malignant hyperthermia**. *Paracetamol* - **Paracetamol** (acetaminophen) is an **analgesic** and **antipyretic**. - While it can help manage fever, it does not address the fundamental muscle rigidity, metabolic acidosis, or **calcium dysregulation** characteristic of malignant hyperthermia. *Diazepam* - **Diazepam** is a benzodiazepine primarily used for its **anxiolytic**, sedative, and **anticonvulsant** properties, acting on GABA receptors. - It would not treat the underlying **muscle rigidity** and hypermetabolism of malignant hyperthermia, though it might reduce anxiety.

Q: What is the first line of management in malignant hyperthermia?

Discontinue triggering agent. ***Discontinue triggering agent*** - The immediate and most crucial first step is to **discontinue** all **halogenated inhalational anesthetics** and **succinylcholine**, as these are the agents that trigger malignant hyperthermia. - Failure to remove the triggering agents will lead to continued progression of the hypermetabolic state, making other interventions less effective. *Institute cooling* - While **cooling measures** are essential for managing the **hyperthermia** and are implemented early, they are secondary to discontinuing the causative agent. - Cooling alone will not cease the underlying muscle hypermetabolism and calcium release without removing the triggering substance. *IV dantrolene 2.5 mg/kg* - **Dantrolene** is the specific antidote for malignant hyperthermia, directly interfering with calcium release from the sarcoplasmic reticulum, and should be administered as soon as possible after suspicion. - However, the very first step is to stop the continuous exposure to the triggering agents that are causing the condition. *Administer bicarbonate* - **Bicarbonate** is used to manage the **metabolic acidosis** that develops in malignant hyperthermia due to excessive CO2 production and lactic acid. - This is a supportive measure addressing a consequence of the condition, not the primary intervention to halt the hypermetabolic crisis itself.

Q: 55-year-old female, a known case of thyrotoxicosis under control, posted for abdominoperineal resection. During surgery, there was sudden drop in B.P. and end-tidal CO2 decreased from 40 to 10 mmHg. On auscultation, there was a mill wheel murmur. What is the diagnosis?

Air embolism. ***Air embolism*** - A sudden drop in **blood pressure**, decreased **end-tidal CO2**, and a **mill wheel murmur** (a churning sound heard over the precordium) are classical signs of an **air embolism**. - Air entering the vascular system, particularly the right side of the heart, obstructs blood flow and gas exchange. *Hypoxia* - While hypoxia can lead to a drop in blood pressure and changes in end-tidal CO2, it typically does not cause a **mill wheel murmur**. - Hypoxia would usually manifest with signs of inadequate oxygenation, such as **cyanosis** or desaturation, which are not mentioned here as the primary finding. *Thyroid storm* - Thyroid storm is characterized by a rapid onset of **hypermetabolism**, including fever, tachycardia, hypertension (initially), and altered mental status. - Although it can cause cardiovascular collapse, the specific combination of a sudden drop in **end-tidal CO2** and a **mill wheel murmur** is not characteristic of thyroid storm. *Bleeding* - Significant bleeding would cause a drop in **blood pressure** and an increase in **heart rate** but typically leads to an increase in **end-tidal CO2** due to compensatory hyperventilation or metabolic acidosis. - A **mill wheel murmur** is not a feature of hypovolemia due to bleeding.

Q: Most common cause of metabolic acidosis in anesthesia is:

Hypotension. ***Hypotension*** - **Hypotension** leads to **tissue hypoperfusion** and **anaerobic metabolism**, resulting in the production and accumulation of **lactic acid**. - This increased lactic acid significantly contributes to **metabolic acidosis**, making it a common cause in anesthetic settings due to surgical stress and fluid shifts. *Renal failure* - While **renal failure** can cause **metabolic acidosis** due to impaired acid excretion, it is not the most common acute cause in the perioperative setting among otherwise healthy individuals undergoing anesthesia. - Its onset is typically more chronic, and its presentation during anesthesia would usually be an exacerbation of pre-existing disease rather than a primary acute cause. *Hypoventilation* - **Hypoventilation** primarily causes **respiratory acidosis** due to the retention of carbon dioxide, not metabolic acidosis. - Although it can lead to hypoxia in severe cases, the immediate and direct effect on acid-base balance is an increase in **PCO2**. *Ketoacidosis* - **Ketoacidosis** (e.g., diabetic ketoacidosis) is characterized by the overproduction of **ketone bodies**, leading to metabolic acidosis. - While severe, it's typically associated with specific underlying conditions like uncontrolled diabetes and is not the most common cause of acidosis during routine anesthesia in patients without pre-existing metabolic disorders.

Q: Malignant hyperthermia is a rare complication of the use of the following anaesthetic:

Halothane. **Halothane** - **Halothane** is a potent volatile anesthetic and a classic trigger for **malignant hyperthermia** due to its effect on ryanodine receptors, leading to excessive calcium release from the sarcoplasmic reticulum. - While its use has declined, it remains a critical example of an anesthetic agent known to induce this life-threatening genetic disorder. *Thiopentone Sodium* - **Thiopentone sodium** is an intravenous barbiturate anesthetic and is **not associated** with triggering malignant hyperthermia. - It is often used for induction of anesthesia and has a different mechanism of action involving GABA receptors. *Ether* - **Diethyl ether** was one of the earliest general anesthetics but is **not a trigger** for malignant hyperthermia. - Its use has largely been discontinued due to its flammability and adverse side effects, but it doesn't cause MH. *Ketamine* - **Ketamine** is a dissociative anesthetic that acts as an NMDA receptor antagonist and is **not a trigger** for malignant hyperthermia. - It is often used for its analgesic and sedative properties and is considered safe in patients susceptible to MH.

Q: What is the earliest sign of malignant hyperthermia?

Elevated end tidal carbon dioxide is an early sign. ***Elevated end tidal carbon dioxide is an early sign*** - An abrupt and unexplained **increase in end-tidal carbon dioxide (ETCO2)** is often the *first and most sensitive indicator* of malignant hyperthermia during anesthesia. - This rise reflects the excessive **CO2 production** due to uncontrolled muscle metabolism before a significant temperature increase is observed. *Dantrolene sodium is the drug of choice* - While **dantrolene sodium** is indeed the definitive treatment for malignant hyperthermia, it is *not an early sign* of the condition. - Administration of dantrolene is initiated *after* the signs and symptoms, such as elevated ETCO2, become apparent. *Isoflurane is an absolute contraindication* - **Volatile anesthetic agents** like **isoflurane** are known triggers for malignant hyperthermia in susceptible individuals. - Therefore, using isoflurane in a patient with a history of or susceptibility to MH is indeed contraindicated, but this statement describes a *trigger* or *preventative measure*, not an early sign. *Characterized by muscle rigidity, hyperthermia, and metabolic acidosis* - **Muscle rigidity**, **hyperthermia**, and **metabolic acidosis** are *later and more prominent signs* of malignant hyperthermia as the uncontrolled muscle contraction and metabolism progress. - They represent the more advanced stages of the syndrome and typically follow the initial rise in ETCO2.

Question 1

A child during anesthesia with halothane and succinylcholine develops severe stiffness of masseters. What is the most probable diagnosis?

Accepted Answer

Malignant hyperthermia

Answer

Halothane hepatitis

Answer

Neuroleptic malignant syndrome

Answer

Anaphylaxis

Question 2

30 year old lady was on the OT and during the mastoidectomy, after having inhalational anaesthesia, suddenly developed fever, increased heart rate, raised BP, acidosis and arrythmia. What is the next best intervention?

Accepted Answer

Dantrolene

Answer

Antipyretics

Answer

Sodium bicarbonate

Answer

Procainamide

Question 3

A 10-year old child is undergoing squint surgery. He suddenly developed increased heart rate, arrhythmia, high fever, metabolic and respiratory acidosis on arterial blood gases and elevation of end tidal CO2. Which of the following would be the first agent of choice in the management of this condition?

Accepted Answer

Dantrolene

Answer

Procainamide

Answer

Sodium bicarbonate

Answer

Paracetamol

Question 4

A patient presents with malignant hyperthermia and metabolic acidosis. Immediate treatment should be started with:

Accepted Answer

Intravenous Dantrolene

Answer

Intravenous fluids

Answer

Sodium bicarbonate

Answer

Paracetamol

Question 5

Drug used in treatment of malignant hyperthermia is

Accepted Answer

Dantrolene

Answer

Phenobarbitone

Answer

Paracetamol

Answer

Diazepam

Question 6

What is the first line of management in malignant hyperthermia?

Accepted Answer

Discontinue triggering agent

Answer

Institute cooling

Answer

IV dantrolene 2.5 mg/kg

Answer

Administer bicarbonate

Question 7

55-year-old female, a known case of thyrotoxicosis under control, posted for abdominoperineal resection. During surgery, there was sudden drop in B.P. and end-tidal CO2 decreased from 40 to 10 mmHg. On auscultation, there was a mill wheel murmur. What is the diagnosis?

Accepted Answer

Air embolism

Answer

Hypoxia

Answer

Thyroid storm

Answer

Bleeding

Question 8

Most common cause of metabolic acidosis in anesthesia is:

Accepted Answer

Hypotension

Answer

Renal failure

Answer

Hypoventilation

Answer

Ketoacidosis

Question 9

Malignant hyperthermia is a rare complication of the use of the following anaesthetic:

Accepted Answer

Halothane

Answer

Thiopentone sodium

Answer

Ether

Answer

Ketamine

Question 10

What is the earliest sign of malignant hyperthermia?

Accepted Answer

Elevated end tidal carbon dioxide is an early sign

Answer

Hyperkalemia and myoglobinuria

Answer

Masseter muscle rigidity after succinylcholine

Answer

Tachycardia and arrhythmias

Complications in Anesthesia — MCQs

Complications in Anesthesia — MCQs

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