Complications in Anesthesia Practice Questions

Q: Intra-arterial injection of thiopentone. All are true except:

Treatment of choice is stellate ganglion block.. **Explanation:** Intra-arterial injection of Thiopentone is a medical emergency characterized by severe pain, intense vasoconstriction, and potential gangrene. **1. Why Option C is the correct answer (The "Except"):** While a **Stellate Ganglion Block** (or Brachial Plexus Block) is a recognized treatment modality used to achieve sympathetic blockade and subsequent vasodilation, it is **not the treatment of choice**. The immediate priority and treatment of choice is to **leave the needle in situ** and inject vasodilators (like Papaverine) directly into the artery to counteract the intense vasospasm. **2. Analysis of other options:** * **Option A:** Thiopentone is highly alkaline (pH 10.5). When injected into an artery, it reacts with blood to form **crystals** that lodge in small arterioles and capillaries. This triggers endothelial damage, platelet aggregation, and intense **vasoconstriction**, leading to distal ischemia. * **Option B:** Immediate pharmacological management involves injecting **Papaverine** (40–80 mg) or **Lidocaine** (1%) through the same needle to induce direct vasodilation and stabilize the endothelium. * **Option D:** **Heparinization** is performed to prevent secondary thrombosis and microvascular occlusion resulting from the chemical endarteritis. **Clinical Pearls for NEET-PG:** * **Presentation:** "Hand of burning fire" – sudden, excruciating pain distal to the injection site. * **Immediate Action:** Do NOT remove the needle; use it for drug administration. * **Other Treatments:** Elevation of the limb, analgesia, and sometimes surgical embolectomy if large clots form. * **Prevention:** Always use a test dose and check for arterial pulsations before injecting Thiopentone.

Q: Anaphylaxis is caused by which of the following agents?

Althesin. ### Explanation **Correct Option: B. Althesin** Althesin was an intravenous anesthetic agent consisting of a mixture of two steroids: **Alphaxalone and Alphadolone**. It was notorious for causing severe **Type I hypersensitivity reactions (anaphylaxis)**. The primary culprit was the solvent used to dissolve these steroids, **Cremophor EL** (polyoxyethylated castor oil). Due to a high incidence of life-threatening anaphylactoid reactions (approximately 1 in 1,000 to 1 in 10,000 administrations), Althesin was withdrawn from clinical use in 1984. **Analysis of Incorrect Options:** * **A. N2O (Nitrous Oxide):** An inorganic gas that does not cause anaphylaxis. Its primary concerns are diffusion hypoxia, expansion of closed gas spaces, and megaloblastic anemia (via Vitamin B12 inhibition). * **C. Halothane:** While Halothane is associated with "Halothane Hepatitis" (an immune-mediated hepatotoxicity), it does not typically cause acute anaphylactic reactions. * **D. Propofol:** Modern Propofol is formulated in a soybean oil/egg lecithin emulsion. While it can cause allergic reactions in patients with specific sensitivities, its incidence is significantly lower than that of Althesin. Interestingly, the original formulation of Propofol also used Cremophor EL but was changed due to the same anaphylactic risks seen with Althesin. **High-Yield Clinical Pearls for NEET-PG:** * **Neuromuscular Blocking Agents (NMBAs):** These are the **most common** cause of perioperative anaphylaxis (Succinylcholine and Rocuronium being the most frequent). * **Latex:** The second most common cause of intraoperative anaphylaxis. * **Cremophor EL:** Also found in the original formulation of **Propanidid** and the chemotherapy drug **Paclitaxel**, both of which are associated with hypersensitivity. * **Management:** The drug of choice for anaphylaxis is **Adrenaline (Epinephrine)**, administered IM (0.5 mg) or IV (titrated doses).

Q: Post dural puncture headache is typically located in which region?

Occipital. **Explanation:** Post-Dural Puncture Headache (PDPH) is a common complication following spinal anesthesia or accidental dural puncture during epidural placement. **Why Occipital is Correct:** The underlying mechanism of PDPH is the leakage of Cerebrospinal Fluid (CSF) through the dural hole, leading to **low CSF pressure**. This loss of buoyancy causes the brain to sag in the upright position, stretching pain-sensitive structures like the dura mater and cranial nerves (V, IX, and X). The pain is characteristically **positional** (worsens on standing, relieved by lying flat) and is most commonly felt in the **occipital and frontal regions**, often radiating to the neck and shoulders. In the context of standard medical examinations, the **occipital** region is the classic hallmark location. **Analysis of Incorrect Options:** * **A & B (Retro-orbital and Frontal):** While PDPH can involve the frontal region, it is rarely isolated to the retro-orbital area. The occipital distribution is more specific to the traction on the tentorium cerebelli. * **D (Temporal):** Temporal pain is more characteristic of conditions like giant cell arteritis or tension headaches, rather than the gravitational traction seen in PDPH. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Treatment:** Epidural Blood Patch (EBP) – 15-20 ml of autologous blood is injected into the epidural space. * **Risk Factors:** Young age, female gender, pregnancy, and the use of large-bore/cutting needles (e.g., Quincke). * **Prevention:** Use of small-gauge, non-cutting (pencil-point) needles like **Whitacre** or **Sprotte**. * **Associated Symptom:** Diplopia due to **6th Cranial Nerve (Abducens)** palsy is the most common cranial nerve involvement.

Q: Following accidental intra-arterial injection of thiopental, what is the immediate management step?

Remove the needle. **Explanation:** The accidental intra-arterial injection of **Thiopental** (an alkaline solution with pH 10.5) leads to the formation of micro-crystals upon contact with blood. these crystals cause intense chemical endarteritis, vasospasm, and subsequent distal ischemia or gangrene. **Why "Remove the needle" is the correct first step:** In any scenario involving an accidental iatrogenic injury during a procedure, the immediate priority is to **stop the administration of the offending agent** to prevent further tissue damage. Removing the needle (or stopping the injection) minimizes the volume of the drug entering the arterial circulation, thereby limiting the severity of the chemical insult. **Analysis of Incorrect Options:** * **B & C (Intra-arterial Heparin/Papaverine):** While these are vital components of the *subsequent* management (Heparin to prevent thrombosis and Papaverine/Lidocaine to relieve vasospasm), they are secondary to stopping the initial insult. * **D (Stellate Ganglion Block):** This is a definitive treatment used to achieve sympathetic blockade and promote vasodilation in the affected limb, but it is never the "immediate" first step. **NEET-PG High-Yield Pearls:** * **Mechanism of Injury:** Thiopental crystals precipitate in the small arteries, leading to **norepinephrine release** and profound vasospasm. * **Clinical Presentation:** The patient typically complains of sudden, "shooting" pain radiating distally, followed by blanching and loss of distal pulses. * **Management Protocol:** 1. Stop injection/Remove needle. 2. Dilute the drug (inject Normal Saline through the same catheter if still in situ). 3. Relieve vasospasm (intra-arterial Lidocaine or Papaverine). 4. Sympathetic block (Stellate ganglion or Brachial plexus block). 5. Anticoagulation (Heparin) to prevent secondary thrombosis.

Q: A 25-year-old female develops masseter muscle spasm after IV succinylcholine administration. End-tidal CO2 progressively increases, heart rate increases, and temperature rises. What is the EXCEPTIONAL management for this condition?

Administer halothane to decrease the heart rate.. ### Explanation The clinical presentation—**masseter muscle spasm** following succinylcholine, rising **ETCO2** (the earliest sign), tachycardia, and hyperthermia—is diagnostic of **Malignant Hyperthermia (MH)**. MH is a pharmacogenetic hypermetabolic state triggered by volatile anesthetics and depolarizing muscle relaxants. #### 1. Why Option A is the Correct (Exceptional) Choice **Halothane** is a potent trigger for Malignant Hyperthermia. In a patient already experiencing an MH crisis, administering halothane would exacerbate the calcium release from the sarcoplasmic reticulum, worsening the hypermetabolic state and potentially leading to death. While halothane can decrease heart rate via myocardial depression, its use is **absolutely contraindicated** in this scenario. #### 2. Analysis of Incorrect Options (Standard Management) * **Option B (Hyperventilate with 100% O2):** This is a primary step. High-flow oxygen helps meet increased metabolic demands, and hyperventilation helps wash out the rapidly rising CO2. * **Option C (Active Cooling):** Hyperthermia in MH can be extreme. Cooling (cold IV fluids, surface cooling, or gastric lavage) is essential to prevent heat-induced organ damage. * **Option D (Treat Acidosis):** MH causes severe mixed respiratory and metabolic (lactic) acidosis. Administration of Sodium Bicarbonate (1-2 mEq/kg) is standard to stabilize pH and treat hyperkalemia. #### 3. NEET-PG High-Yield Pearls * **Definitive Treatment:** **Dantrolene** (a Ryanodine receptor antagonist) is the drug of choice. Dose: 2.5 mg/kg IV bolus, repeated up to 10 mg/kg. * **Earliest Sign:** Increase in End-tidal CO2 (ETCO2). * **Late Sign:** Hyperthermia (can rise 1°C every 5 minutes). * **Genetic Defect:** Mutation in the **RYR1 gene** (Ryanodine receptor) on Chromosome 19. * **Safe Agents:** Propofol, Ketamine, Etomidate, and non-depolarizing NMBs (e.g., Vecuronium).

Q: Suxamethonium causes all EXCEPT:

Hypokalemia. **Explanation:** **Suxamethonium (Succinylcholine)** is the only depolarizing neuromuscular blocker used clinically. It acts as an agonist at the nicotinic acetylcholine receptors, causing prolonged depolarization of the motor endplate. **Why Hypokalemia is the Correct Answer:** Suxamethonium does **not** cause hypokalemia; instead, it characteristically causes **Hyperkalemia**. During the phase of generalized muscle fasciculations, potassium is released from the intracellular compartment into the extracellular fluid. In a healthy individual, serum potassium typically rises by **0.5 mEq/L**. However, in patients with up-regulated receptors (e.g., burns, trauma, or denervation injuries), this rise can be life-threatening, leading to cardiac arrest. **Analysis of Incorrect Options:** * **A. Muscle pain:** Postoperative myalgia is a common side effect caused by the initial uncoordinated muscle fasciculations. It is most frequently seen in young adults undergoing ambulatory surgery. * **B. Malignant hyperthermia:** Suxamethonium is a potent **triggering agent** for Malignant Hyperthermia (MH) in genetically susceptible individuals (RYR1 receptor mutation). * **C. Hyperkalemia:** As explained above, the efflux of potassium during depolarization is a hallmark side effect of the drug. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice:** For Rapid Sequence Induction (RSI) due to its rapid onset (30–60s) and short duration (5–10 mins). * **Metabolism:** Hydrolyzed by **Pseudocholinesterase** (Plasma cholinesterase). Prolonged apnea occurs in patients with atypical pseudocholinesterase (diagnosed by Dibucaine number). * **Dual Block (Phase II Block):** Occurs with repeated doses or infusion, where the block takes on characteristics of a non-depolarizing block. * **Other Side Effects:** Bradycardia (especially in children or with a second dose), increased intraocular, intragastric, and intracranial pressure.

Q: Dantrolene is used in the treatment of which of the following conditions?

All of the above. **Explanation:** The correct answer is **D. All of the above**. Dantrolene sodium is a muscle relaxant that acts by binding to the **Ryanodine Receptor (RyR1)** on the sarcoplasmic reticulum of skeletal muscle. This inhibits the release of calcium ions into the cytosol, thereby preventing the sustained muscle contraction and hypermetabolic state that leads to life-threatening hyperthermia. * **Malignant Hyperthermia (MH):** Dantrolene is the **drug of choice** and the only specific treatment for MH. It halts the uncontrolled calcium release triggered by volatile anesthetics or succinylcholine. * **Neuroleptic Malignant Syndrome (NMS):** While dopamine agonists (Bromocriptine) are primary, Dantrolene is used as an adjunct to reduce muscle rigidity and core temperature in severe cases. * **Thyrotoxicosis/Thyroid Storm:** In extreme cases where hyperthermia is refractory to standard cooling and anti-thyroid measures, Dantrolene can be used to reduce the peripheral heat production from skeletal muscle. **Clinical Pearls for NEET-PG:** 1. **Mechanism:** Direct-acting skeletal muscle relaxant (does not affect cardiac or smooth muscle significantly at therapeutic doses). 2. **Dose for MH:** 2.5 mg/kg IV bolus, repeated every 5–10 minutes until symptoms subside (max dose usually 10 mg/kg). 3. **Side Effects:** Significant muscle weakness and potential hepatotoxicity (with chronic oral use). 4. **Preparation:** Each vial of Dantrolene contains **20 mg** of the drug and must be reconstituted with **60 mL of sterile water**. It contains **mannitol** to improve solubility and promote diuresis.

Question 1

A 20-year-old man complains of headache after spinal anesthesia. Which of the following is the likely cause?

Accepted Answer

Cerebrospinal fluid leak

Answer

Raised intracranial pressure

Answer

Meningitis

Answer

Encephalitis

Question 2

Intra-arterial injection of thiopentone. All are true except:

Accepted Answer

Treatment of choice is stellate ganglion block.

Answer

Intra-arterial thiopentone can form crystals in arterioles and capillaries and cause intense vasoconstriction.

Answer

It should be treated promptly with papaverine and lidocaine.

Answer

Heparinization can also be done.

Question 3

Anaphylaxis is caused by which of the following agents?

Accepted Answer

Althesin

Answer

N2O

Answer

Halothane

Answer

Propofol

Question 4

Post dural puncture headache is typically located in which region?

Accepted Answer

Occipital

Answer

Retro-orbital

Answer

Frontal

Answer

Temporal

Question 5

Following accidental intra-arterial injection of thiopental, what is the immediate management step?

Accepted Answer

Remove the needle

Answer

Administer intra-arterial heparin

Answer

Administer intra-arterial papaverine

Answer

Perform a stellate ganglion block

Question 6

A 25-year-old female develops masseter muscle spasm after IV succinylcholine administration. End-tidal CO2 progressively increases, heart rate increases, and temperature rises. What is the EXCEPTIONAL management for this condition?

Accepted Answer

Administer halothane to decrease the heart rate.

Answer

Hyperventilate with 100% oxygen.

Answer

Implement active cooling measures.

Answer

Treat the acidosis.

Question 7

Suxamethonium causes all EXCEPT:

Accepted Answer

Hypokalemia

Answer

Muscle pain

Answer

Malignant hyperthermia

Answer

Hyperkalemia

Question 8

Hyperkalemia is seen with succinylcholine in all of the following conditions except?

Accepted Answer

Myasthenia gravis

Answer

Tetanus

Answer

Burns

Answer

Muscular dystrophy

Question 9

Which of the following neuromuscular blocking agents is most commonly associated with bradycardia during anesthesia?

Accepted Answer

Atracurium

Answer

Pancuronium

Answer

Vecuronium

Answer

All of the above

Question 10

Dantrolene is used in the treatment of which of the following conditions?

Accepted Answer

All of the above

Answer

Malignant hyperthermia

Answer

Neuroleptic malignant syndrome

Answer

Thyrotoxicosis-induced hyperthermia

Complications in Anesthesia — MCQs

Complications in Anesthesia — MCQs

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