Complications in Anesthesia Practice Questions

Q: Which of the following is the commonest nerve injury due to maintaining the same position for a prolonged period during general anesthesia?

Ulnar neuropathies. **Explanation:** **Ulnar neuropathy** is the most common peripheral nerve injury associated with general anesthesia. The nerve is particularly vulnerable at the elbow as it passes through the **cubital tunnel** (postcondylar groove of the humerus). During anesthesia, the loss of muscle tone and protective pain reflexes, combined with prolonged pressure against the operating table or improper padding, leads to ischemia or compression of the nerve. It is more common in males and patients with a high or low BMI. **Analysis of Options:** * **Ulnar Nerve (Option C):** Correct. Large-scale studies (like the ASA Closed Claims Project) consistently identify ulnar neuropathy as the most frequent nerve injury, often manifesting as "claw hand" or sensory loss in the medial 1.5 fingers. * **Brachial Plexus (Option B):** This is the second most common injury. It typically occurs due to excessive abduction of the arm (>90 degrees), external rotation of the head, or the use of shoulder braces in the Trendelenburg position. * **Common Peroneal Nerve (Option A):** This is the most common nerve injury of the **lower extremity**. It occurs when the lateral aspect of the knee (fibular head) is compressed against stirrups in the lithotomy position, leading to foot drop. **Clinical Pearls for NEET-PG:** * **Most common nerve injured (Overall):** Ulnar Nerve. * **Most common lower limb nerve injured:** Common Peroneal Nerve. * **Most common cause of Brachial Plexus injury:** Excessive arm abduction (>90°). * **Prevention:** Use of foam padding at the elbow, maintaining the forearm in a neutral or supinated position, and avoiding prolonged lithotomy time. * **Radial Nerve Injury:** Usually caused by a tight NIBP cuff or pressure against the humerus (leads to wrist drop).

Q: Which drug is used in the treatment of malignant hyperthermia?

Dantrolene. **Explanation:** **Malignant Hyperthermia (MH)** is a rare but life-threatening pharmacogenetic hypermetabolic crisis triggered by volatile anesthetics (e.g., Halothane, Isoflurane) and the depolarizing muscle relaxant Succinylcholine. **Why Dantrolene is the Correct Answer:** The underlying pathology of MH involves a mutation in the **Ryanodine Receptor (RYR1)**, leading to an uncontrolled release of calcium from the sarcoplasmic reticulum into the skeletal muscle cytoplasm. This causes sustained muscle contraction, excessive heat production, and metabolic acidosis. **Dantrolene** is a direct-acting skeletal muscle relaxant that acts as an antagonist to the RYR1 receptor. It inhibits the release of calcium, thereby reversing the hypermetabolic state. It is the only specific antidote for MH. **Analysis of Incorrect Options:** * **B. Diazepam:** A benzodiazepine used for sedation and anxiolysis; it has no effect on the intracellular calcium release mechanism in skeletal muscles. * **C. Paracetamol:** An antipyretic that acts centrally. It is ineffective in MH because the fever in MH is caused by peripheral muscular metabolic activity, not a change in the hypothalamic set-point. * **D. Phenobarbitone:** A barbiturate used primarily as an anticonvulsant; it plays no role in treating MH. **High-Yield Clinical Pearls for NEET-PG:** * **Earliest Sign:** Increase in **End-Tidal CO₂ (ETCO₂)**. * **Late Sign:** Hyperthermia (can rise 1°C every 5 minutes). * **Dose of Dantrolene:** 2.5 mg/kg IV bolus, repeated every 5–10 minutes until symptoms subside (max dose 10 mg/kg). * **Safe Agents:** Propofol, Ketamine, Etomidate, and Nitrous Oxide. * **Diagnosis:** Gold standard is the **Caffeine-Halothane Contracture Test (CHCT)**.

Q: A 30-year-old female who underwent surgery under spinal anesthesia developed a post-spinal headache. How long does it typically take for the headache to subside?

Up to 2 weeks. **Explanation:** Post-Dural Puncture Headache (PDPH) is a common complication following spinal anesthesia, caused by the persistent leakage of cerebrospinal fluid (CSF) through the dural puncture site. This leads to low CSF pressure and loss of the "cushioning" effect, causing traction on intracranial vascular structures when the patient is upright. **Why Option C is Correct:** While most cases of PDPH are self-limiting and resolve within **5 to 7 days**, clinical studies and standard textbooks (like Miller’s Anesthesia) state that symptoms can persist for **up to 2 weeks** in a significant number of patients. If the headache lasts longer than 14 days, clinicians should investigate alternative diagnoses or consider an epidural blood patch. **Analysis of Incorrect Options:** * **Option A (10 minutes):** This is far too short. PDPH typically has a delayed onset (24–48 hours post-procedure) and requires time for the dural hole to heal. * **Option B (4 days):** While many patients show improvement by day 4, it is not the upper limit of the typical duration. * **Option D (2 months):** Chronic headaches lasting months are rare and usually indicate a complication (like a subdural hematoma) rather than simple PDPH. **High-Yield Clinical Pearls for NEET-PG:** * **Character:** Classically **frontal or occipital** and strictly **positional** (worsens on standing/sitting, relieved by lying flat). * **Risk Factors:** Young age, female gender, pregnancy, and use of large-bore or cutting-tip needles (e.g., Quincke). * **Prevention:** Use of small-gauge (25G-27G) **non-cutting (pencil-point)** needles like **Sprotte or Whitacre**. * **Management:** Conservative (bed rest, hydration, caffeine). The **Gold Standard** treatment for persistent/severe PDPH is an **Epidural Blood Patch**.

Q: Shivering is most commonly seen with the use of which anesthetic agent?

Halothane. ### **Explanation** **Correct Option: A (Halothane)** Post-anesthetic shivering (PAS) is a frequent complication of general anesthesia, and among the options provided, **Halothane** is most notoriously associated with it. **The Underlying Concept:** Halothane causes significant peripheral vasodilation and profoundly depresses the hypothalamic thermoregulatory center. This leads to a rapid drop in core body temperature (hypothermia). During the recovery phase, as the anesthetic concentration decreases, the body’s thermoregulatory mechanisms "reset" and attempt to generate heat to compensate for the hypothermia, resulting in intense shivering. This is often referred to as the "Halothane Shakes." **Analysis of Incorrect Options:** * **B. Cyclopropane:** While it can cause some sympathetic stimulation, it is not primarily associated with the intense thermoregulatory shivering characteristic of Halothane. * **C. Ether:** Ether is an irritant and causes significant catecholamine release, which may mask or alter the shivering response compared to the potent vasodilatory effect of Halothane. * **D. Thiopentone:** As an intravenous induction agent with a short duration of action, it does not typically cause the prolonged hypothermia required to trigger significant post-operative shivering. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice for Shivering:** **Meperidine (Pethidine)** is the gold standard treatment for post-operative shivering (dose: 12.5–25 mg IV). It works by lowering the shivering threshold. * **Other agents used:** Clonidine, Tramadol, and Dexmedetomidine. * **Mechanism:** Shivering increases oxygen consumption by up to **300–400%**, which can be dangerous in patients with limited cardiac reserve (CAD). * **Differential:** Do not confuse anesthetic-induced shivering with "Emergence Delirium," which is also common with Halothane in pediatric patients.

Q: Hyperkalemia is caused by which of the following?

Succinylcholine. **Explanation:** **Succinylcholine (Suxamethonium)** is a depolarizing neuromuscular blocker that acts as an agonist at the nicotinic acetylcholine receptors (nAChR) at the motor endplate. When it binds, it causes prolonged depolarization of the muscle membrane. This process opens ion channels, leading to an efflux of **potassium (K+)** from the intracellular space into the extracellular fluid. In a healthy individual, this typically results in a transient, clinically insignificant rise in serum potassium (approx. **0.5 mEq/L**). **Why the other options are incorrect:** * **Atracurium & Pancuronium:** These are **non-depolarizing** neuromuscular blockers. They act as competitive antagonists at the nAChR, preventing depolarization. Consequently, they do not cause ion flux or potassium release. (Note: Atracurium is known for histamine release and its metabolite *laudanosine*, which can cause seizures). * **Nitrous Oxide:** This is an inhalational anesthetic agent. Its primary significant hematological complication is the inhibition of Vitamin B12 (methionine synthase), leading to megaloblastic anemia, not electrolyte imbalances like hyperkalemia. **High-Yield Clinical Pearls for NEET-PG:** * **Exaggerated Hyperkalemia:** Succinylcholine can cause life-threatening hyperkalemia in patients with **upregulation of extrajunctional receptors**. This occurs in: * Severe burns (after 24-48 hours) * Crush injuries/Massive trauma * Upper/Lower motor neuron lesions (Paraplegia/Quadriplegia) * Prolonged immobilization * **Antidote:** There is no pharmacological reversal for Succinylcholine; it is metabolized by **pseudocholinesterase**. * **Other Side Effects:** Muscle fasciculations, myalgia, increased intraocular/intragastric pressure, and it is a potent trigger for **Malignant Hyperthermia**.

Q: What are the potential consequences of an intra-arterial injection of a drug?

All of the above. **Explanation:** Intra-arterial (IA) injection of drugs (most commonly Thiopentone or Diazepam) is a dreaded anesthetic complication. The primary pathophysiology involves **intense vasospasm** and the formation of **micro-crystals** that obstruct small capillaries, leading to severe distal ischemia and chemical endarteritis. **Analysis of Options:** * **Mottling of the affected limb:** This is an early sign of ischemia. The drug causes immediate vasoconstriction and endothelial damage, leading to a "patchy" or marbled appearance of the skin due to uneven blood flow. * **Development of Compartment Syndrome:** Ischemia leads to tissue hypoxia, which increases capillary permeability. This results in massive edema within the tight fascial compartments of the limb. As pressure rises, it further compromises blood flow, potentially leading to muscle necrosis. * **Absence of a palpable pulse:** While the initial insult is at the arteriolar level, the resulting edema, progressive thrombosis, and severe vasospasm can eventually lead to the loss of distal pulses in the affected extremity. **Clinical Pearls for NEET-PG:** 1. **Classic Presentation:** Sudden, severe "burning" pain distal to the site of injection, followed by blanching or mottling. 2. **Management Gold Standard:** * **Leave the catheter in situ** (to administer vasodilators). * **Dilute the drug:** Flush with Heparinized saline. * **Vasodilation:** Intra-arterial **Papaverine**, Lidocaine, or Phentolamine. * **Sympathetic Block:** Stellate ganglion block or Brachial plexus block to relieve vasospasm. 3. **Prevention:** Always check for arterial pulsations before injecting and use a "test dose" of Thiopentone (2.5% is safer than 5%).

Question 1

Abnormal plasma choline esterase produces apnea due to which of the following?

Accepted Answer

Suxamethonium

Answer

Halothane

Answer

Lignocaine

Answer

Isoflurane

Question 2

Which of the following is the commonest nerve injury due to maintaining the same position for a prolonged period during general anesthesia?

Accepted Answer

Ulnar neuropathies

Answer

Common peroneal nerve injury

Answer

Brachial plexus injuries

Answer

None of the above

Question 3

Which drug is used in the treatment of malignant hyperthermia?

Accepted Answer

Dantrolene

Answer

Diazepam

Answer

Paracetamol

Answer

Phenobarbitone

Question 4

All are true about accidental intra-arterial injection of Thiopentone except:

Accepted Answer

To relieve pain, we have to immediately remove the misplaced arterial cannula.

Answer

Immediate intense vasoconstriction and excruciating pain

Answer

Cause is precipitation of thiopental crystals in the arterial vessels

Answer

Sympathectomy of the upper extremity produced by stellate ganglion block may relieve vasoconstriction.

Question 5

Post-spinal headache is most commonly due to which of the following mechanisms?

Accepted Answer

Cerebrospinal fluid (CSF) leak

Answer

Meningitis

Answer

Encephalitis

Answer

Increased intracranial pressure (ICT)

Question 6

A 30-year-old female who underwent surgery under spinal anesthesia developed a post-spinal headache. How long does it typically take for the headache to subside?

Accepted Answer

Up to 2 weeks

Answer

Up to 10 minutes

Answer

Up to 4 days

Answer

Up to 2 months

Question 7

A 6-year-old child who has had repeated episodes of otitis media undergoes surgical placement of pressure-equalization (PE) tubes. In the recovery room, she develops a fever of 40degC (104degF), muscle rigidity, dark colored urine, and metabolic and respiratory acidosis. Which of the following therapies is most likely to be beneficial for this child's condition?

Accepted Answer

Intravenous administration of dantrolene

Answer

Acidification of the urine

Answer

Administration of intravenous antibiotics after obtaining blood cultures

Answer

Administration of tetanus immunoglobulin and a booster dose of DTaP

Question 8

Shivering is most commonly seen with the use of which anesthetic agent?

Accepted Answer

Halothane

Answer

Cyclopropane

Answer

Ether

Answer

Thiopentone

Question 9

Hyperkalemia is caused by which of the following?

Accepted Answer

Succinylcholine

Answer

Nitrous oxide

Answer

Atracurium

Answer

Pancuronium

Question 10

What are the potential consequences of an intra-arterial injection of a drug?

Accepted Answer

All of the above

Answer

Mottling of the affected limb

Answer

Development of compartment syndrome

Answer

Absence of a palpable pulse in the affected lower limb

Complications in Anesthesia — MCQs

Complications in Anesthesia — MCQs

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