Pathophysiology of Asphyxia — MCQs

10 questions

Burking includes:

Neurogenic shock is characterized by:

A male patient presents to the emergency department. The arterial blood gas report is as follows: pH, 7.2; pCO2, 81 mmHg; and HCO3, 40 meq/L. Which of the following is the most likely diagnosis?

The lab reports of a patient given below: pH = 7.2, HCO3 = 10 mEq/L, PCO2 = 30 mmHg. This exemplifies which of the following disorders?

Which of the following is not a sign of cerebral compression?

An unconscious child is brought to the casualty. What is the correct sequence of the management?

An unconscious patient was brought to the casualty. ABG reveals metabolic acidosis with hypocalcemia. The urine specimen from this patient is shown below. Identify the substance:

Which of the following is NOT a post-mortem finding in carbon monoxide poisoning?

A loop of thin string is thrown around the neck of the victim in what type of strangulation?

Q10Medium

Which of the following conditions is not associated with an increased risk of malignancy?

Pathophysiology of Asphyxia Indian Medical PG Practice Questions and MCQs

Question 1: Burking includes:

A. Ligature strangulation
B. Drowning mechanism
C. Hanging technique
D. Chest compression and airway obstruction (Correct Answer)

Explanation: ***Chest compression and airway obstruction*** - Burking is a **homicidal method** of suffocation that involves **covering the mouth and nose** (airway obstruction) combined with **compressing the chest or abdomen** to prevent breathing. - Named after **William Burke**, this technique was used to kill victims without leaving obvious signs of violence, making deaths appear natural. *Ligature strangulation* - Involves using a **cord, rope, or similar object** around the neck to compress blood vessels and/or airway. - Leaves characteristic **ligature marks** on the neck, which burking aims to avoid by using manual compression instead. *Drowning mechanism* - Involves **submersion in liquid** causing respiratory impairment and asphyxia. - Completely different mechanism from burking, which involves **manual suffocation** on dry land without water involvement. *Hanging technique* - Hanging involves **suspension of the body by the neck**, causing death through compression of neck structures. - This is completely different from burking and leaves distinct **hanging marks** on the neck, which burking specifically avoids.

Question 2: Neurogenic shock is characterized by:

A. Hypotension and bradycardia (Correct Answer)
B. Hypotension and tachycardia
C. Hypertension and tachycardia
D. Hypertension and bradycardia

Explanation: ***Hypotension and bradycardia*** - **Neurogenic shock** results from the loss of **sympathetic vascular tone**, leading to widespread vasodilation and subsequent **hypotension**. - The interruption of sympathetic innervation to the heart can also cause **bradycardia**, as parasympathetic tone becomes unopposed. *Hypotension and tachycardia* - This presentation is typical of other forms of shock, such as **hypovolemic** or **septic shock**, where the body attempts to compensate for low blood pressure with an increased heart rate. - In neurogenic shock, the sympathetic nervous system, which usually causes tachycardia, is dysfunctional. *Hypertension and tachycardia* - This combination is not characteristic of any form of shock; rather, it often indicates a **hyperadrenergic state** or certain types of **hypertensive crisis**. - Shock is fundamentally a state of inadequate tissue perfusion, which typically involves hypotension. *Hypertension and bradycardia* - This combination can be seen in conditions like **Cushing's reflex** (due to increased intracranial pressure) but is not a feature of neurogenic shock [1]. - Neurogenic shock is defined by a loss of sympathetic tone, which leads to vessel dilation and reduced blood pressure.

Question 3: A male patient presents to the emergency department. The arterial blood gas report is as follows: pH, 7.2; pCO2, 81 mmHg; and HCO3, 40 meq/L. Which of the following is the most likely diagnosis?

A. Respiratory alkalosis
B. Metabolic acidosis
C. Respiratory acidosis (Correct Answer)
D. Metabolic alkalosis

Explanation: ***Respiratory acidosis*** - The **pH of 7.2** indicates **acidemia**, while the **elevated pCO2 (81 mmHg)** points to a primary respiratory problem [2]. - The elevated **HCO3 (40 meq/L)** suggests **renal compensation** attempting to buffer the increased carbonic acid [1]. *Respiratory alkalosis* - This condition presents with an **elevated pH (alkalemia)** and a **decreased pCO2**, which is opposite to the given ABG values [2]. - While there might be metabolic compensation with a decreased HCO3, the primary disturbance is an increase in respiratory rate leading to excessive CO2 exhalation. *Metabolic acidosis* - Metabolic acidosis is characterized by a **low pH** and a **low HCO3**, with a compensatory decrease in pCO2 [1]. - The given ABG shows a high HCO3, which rules out primary metabolic acidosis. *Metabolic alkalosis* - This condition would typically show an **elevated pH** and an **elevated HCO3**, with a compensatory increase in pCO2. - While both HCO3 and pCO2 are high in the given ABG, the low pH points to a primary acidosis, not alkalosis.

Question 4: The lab reports of a patient given below: pH = 7.2, HCO3 = 10 mEq/L, PCO2 = 30 mmHg. This exemplifies which of the following disorders?

A. Metabolic alkalosis
B. Respiratory acidosis
C. Metabolic acidosis (Correct Answer)
D. Respiratory alkalosis

Explanation: ***Metabolic acidosis*** - The pH of 7.2 is acidic, and the **bicarbonate (HCO3) of 10 mEq/L** is significantly low (normal: 22-28 mEq/L), indicating a primary metabolic disturbance causing acidosis. - The **PCO2 of 30 mmHg** is also low (normal: 35-45 mmHg), which represents **partial respiratory compensation** through hyperventilation to blow off CO2 and raise pH. - This is a classic example of **metabolic acidosis with respiratory compensation**. *Metabolic alkalosis* - This condition would be characterized by a **high pH** and a **high bicarbonate (HCO3)** level, which is the opposite of the given values. - The body would attempt to compensate by increasing PCO2 through hypoventilation. *Respiratory acidosis* - This would present with a **low pH** and a **high PCO2** (>45 mmHg), indicating a primary respiratory problem leading to CO2 retention and acid accumulation. - Metabolic compensation would show elevated HCO3, not the low HCO3 (10 mEq/L) seen here. *Respiratory alkalosis* - This condition is characterized by a **high pH** (>7.45) and a **low PCO2**, due to excessive ventilation causing CO2 elimination. - While PCO2 is low in the given scenario, the pH is acidic (7.2), not alkalotic, ruling out this diagnosis.

Question 5: Which of the following is not a sign of cerebral compression?

A. Papilloedema
B. Vomiting
C. Bradycardia
D. Hypotension (Correct Answer)

Explanation: ***Hypotension*** - **Hypotension** (low blood pressure) is generally not a direct sign of cerebral compression; rather, **hypertension** (Cushing's triad) is associated with increased intracranial pressure. - While systemic hypotension can reduce cerebral perfusion pressure, it is not a primary compensatory mechanism against rising ICP. *Bradycardia* - **Bradycardia** (slow heart rate) is a key component of the **Cushing's reflex**, which is a physiological response to increased intracranial pressure (ICP) aiming to maintain cerebral perfusion. - It occurs alongside hypertension and irregular respiration in the Cushing's triad. *Papilloedema* - **Papilloedema** refers to swelling of the optic disc due to increased intracranial pressure (ICP), which impedes venous return from the retina. - It is a significant and often late sign of cerebral compression or sustained elevation of ICP. *Vomiting* - **Vomiting**, particularly without nausea and often described as **projectile vomiting**, is a common symptom of increased intracranial pressure. - It results from the stimulation of the vomiting center in the brainstem by the elevated pressure.

Question 6: An unconscious child is brought to the casualty. What is the correct sequence of the management?

A. Circulation, Airway, Breathing
B. Breathing, Circulation, Airway
C. Circulation, Breathing, Airway
D. Airway, Breathing, Circulation (Correct Answer)

Explanation: ***Airway, Breathing, Circulation*** - The **ABC sequence** is the cornerstone of pediatric resuscitation as per **PALS (Pediatric Advanced Life Support) guidelines** - In an unconscious child, a patent **airway** is the absolute first priority - without this, no oxygen can reach the lungs regardless of breathing effort - Once airway patency is ensured, **breathing** must be assessed and supported to provide adequate ventilation and oxygenation - Only after securing airway and breathing should **circulation** be addressed, as effective circulation without oxygenation is futile - This sequence prevents **hypoxic brain injury**, which can occur within 4-6 minutes of oxygen deprivation *Circulation, Airway, Breathing* - This violates the fundamental **ABC principle** of emergency management - Prioritizing **circulation** before establishing a patent **airway** means attempting to circulate deoxygenated blood - Without airway patency, any circulatory support will fail to deliver oxygen to vital organs, leading to **irreversible hypoxic damage** - In pediatric emergencies, respiratory failure is more common than primary cardiac arrest, making airway management even more critical *Breathing, Circulation, Airway* - Attempting to support **breathing** before securing the **airway** is physiologically ineffective - An obstructed airway prevents air entry despite breathing efforts or bag-mask ventilation attempts - This sequence can lead to **gastric distension, aspiration**, and worsening hypoxia - Delays in airway management increase the risk of **cardiac arrest** from prolonged hypoxemia *Circulation, Breathing, Airway* - This sequence dangerously delays **airway management**, the most time-critical intervention - In an unconscious child, airway obstruction from tongue falling back or secretions is common and immediately life-threatening - Without a patent airway, neither breathing support nor circulatory measures can prevent **brain death** from anoxia - Following this sequence contradicts all **international resuscitation guidelines** (PALS, AHA, ERC)

Question 7: An unconscious patient was brought to the casualty. ABG reveals metabolic acidosis with hypocalcemia. The urine specimen from this patient is shown below. Identify the substance:

A. Ethylene glycol (Correct Answer)
B. Methyl alcohol
C. Formaldehyde
D. Paraldehyde

Explanation: ***Ethylene glycol*** - The image shows **calcium oxalate crystals** (both monohydrate, "dumbbell" shapes, and dihydrate, "envelope" shapes), classical findings in **ethylene glycol poisoning**. - Ethylene glycol is metabolized into **oxalic acid**, which precipitates with calcium, leading to **hypocalcemia** and metabolic acidosis due to accumulating organic acids. *Methyl alcohol* - Methyl alcohol poisoning is characterized by metabolites like **formic acid**, causing severe **metabolic acidosis** and visual disturbances, but does not typically lead to calcium oxalate crystalluria. - While it causes profound acidosis, the diagnostic urine crystals seen in the image are not associated with methyl alcohol intoxication. *Formaldehyde* - Formaldehyde poisoning is generally due to ingestion or inhalation, leading to immediate toxicity, often with severe gastrointestinal and respiratory symptoms. - It does not typically metabolize into substances that form **calcium oxalate crystals** in the urine or cause hypocalcemia in this manner. *Paraldehyde* - Paraldehyde is an older sedative/hypnotic that can cause **metabolic acidosis** due to its metabolism into acetic acid, especially in large doses. - However, it does not lead to the formation of **calcium oxalate crystals** in the urine or associated hypocalcemia as seen in the image.

Question 8: Which of the following is NOT a post-mortem finding in carbon monoxide poisoning?

A. Froth at mouth and nose
B. Blue skin discoloration (Correct Answer)
C. Cerebral edema
D. Cherry red discoloration of skin

Explanation: ***Blue skin discoloration*** - **Cyanosis**, or blue skin discoloration, indicates **hypoxia** due to deoxygenated hemoglobin. - In carbon monoxide poisoning, **carboxyhemoglobin** prevents oxygen release but does not cause deoxygenation of the remaining hemoglobin, thus typically avoiding cyanosis. *Froth at mouth and nose* - **Frothing** at the mouth and nose can be seen in various forms of asphyxia and pulmonary edema, which can be secondary to carbon monoxide poisoning if there is significant cardiac or respiratory compromise. - While not universally present, it is a possible finding associated with acute physiological distress preceding death. *Cerebral edema* - **Cerebral edema** is a common post-mortem finding in severe carbon monoxide poisoning due to **hypoxic brain injury**. - Carbon monoxide directly impairs cellular respiration, leading to widespread tissue hypoxia, including the brain, which can manifest as swelling. *Cherry red discoloration of skin* - **Cherry red discoloration** of the skin and lividity is a classic and highly characteristic post-mortem sign of carbon monoxide poisoning. - This color is due to the formation of **carboxyhemoglobin**, which has a bright red hue and is visible through the skin.

Question 9: A loop of thin string is thrown around the neck of the victim in what type of strangulation?

A. Throttling
B. Mugging
C. Garrotting (Correct Answer)
D. Hanging

Explanation: ***Garrotting*** - This involves strangulation where a **thin ligature** (string, wire, or cord) is **thrown around the neck from behind** and tightened by twisting or pulling. - Characterized by a **horizontal ligature mark** around the neck at the level of the thyroid cartilage. - The thin ligature causes **prominent, well-defined ligature marks** and can cause severe damage to underlying neck structures. - Historically used as a method of execution and assassination. *Throttling* - **Manual strangulation** using hands, where the neck is compressed by fingers, thumbs, or palms. - Leaves **fingernail marks, bruises, and abrasions** on the neck rather than a continuous ligature mark. - May show **fingerprint-pattern bruising** and is typically associated with homicidal violence. *Mugging* - In forensic contexts, this refers to an **arm choke** or **headlock strangulation** where the forearm or elbow is placed around the victim's neck. - Also called **brachial strangulation** or **chokehold**. - Distinguished from garrotting by the use of the **arm as the constricting force** rather than a ligature. *Hanging* - Suspension of the body by a ligature around the neck where **body weight provides the constricting force**. - Ligature mark is typically **oblique and higher on the neck**, ascending toward the point of suspension. - Usually shows a **knot mark** and is most commonly suicidal in nature.

Question 10: Which of the following conditions is not associated with an increased risk of malignancy?

A. Down's syndrome
B. Turner syndrome (Correct Answer)
C. Noonan syndrome
D. Klinefelter syndrome

Explanation: **Explanation:** The question evaluates the association between chromosomal aneuploidies and the risk of malignancy. While many genetic syndromes predispose individuals to cancer due to genomic instability or hormonal imbalances, **Turner Syndrome (45, XO)** is generally **not** associated with an overall increased risk of malignancy compared to the general population. In fact, the risk of breast cancer is significantly lower in Turner patients due to ovarian dysgenesis and low estrogen levels. The only specific risk is a **gonadoblastoma**, which occurs only if there is cryptic Y-chromosome mosaicism (45,X/46,XY). **Analysis of Options:** * **Down’s Syndrome (Trisomy 21):** Strongly associated with a 10–20 fold increased risk of **Acute Leukemia** (AMKL/M7 in children <3 years and ALL in older children). * **Noonan Syndrome:** Often called "Pseudo-Turner," this autosomal dominant condition is associated with an increased risk of **Juvenile Myelomonocytic Leukemia (JMML)** and certain solid tumors like neuroblastoma. * **Klinefelter Syndrome (47, XXY):** These patients have a significantly higher risk of **Breast Cancer** (20–50 times higher than normal males) and **Extragonadal Germ Cell Tumors** (specifically mediastinal teratomas). **NEET-PG High-Yield Pearls:** 1. **Turner Syndrome:** Most common cause of primary amenorrhea; characterized by "streak ovaries," webbed neck, and coarctation of the aorta. 2. **Klinefelter Syndrome:** Most common cause of male hypogonadism and infertility; associated with taurodontism. 3. **Cancer Association:** Always remember the "Down-Leukemia" and "Klinefelter-Breast Cancer" links, as these are frequent examiners' favorites.

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