Thermal Injuries — MCQs
To calculate the initial fluid requirement in a burn patient, the best approach is:
A dead body is found to have marks like branching of a tree on the front of the chest. The most likely cause of death could be due to:
Joule burns are seen in
Which of the following is NOT a post-mortem finding in carbon monoxide poisoning?
Type of shock seen in burn cases:
Which of the following statements regarding thermal injury is correct?
A body is discovered with burn marks as shown in the image, resembling a 'crocodile skin' pattern. What is the most likely cause?
A 56-year-old male is burned while sleeping in his home. His right upper and lower extremity and the anterior chest have extensive second-degree burns. What is the total percentage of body surface area affected? Reference: Rule of Nines for Adults - Each arm: 9% - Head: 9% - Anterior trunk: 18% - Posterior trunk: 18% - Each leg: 18% - Total: 99%
A body shows petechial hemorrhages in the eyes. What is the most likely cause?
Which part of brain shows consistent changes in heat stroke
Thermal Injuries Indian Medical PG Practice Questions and MCQs
Question 1: To calculate the initial fluid requirement in a burn patient, the best approach is:
- A. CVP
- B. Urine output
- C. Estimate body surface area (burn) (Correct Answer)
- D. Blood volume measurement
Explanation: ***Estimate body surface area (burn)*** - The primary determinant for initial fluid resuscitation in burn patients is the **total body surface area (TBSA)** affected by the burn. Formulas like the **Parkland formula** use TBSA to calculate initial fluid requirements. - Accurate estimation of TBSA is crucial for preventing both under-resuscitation (leading to shock) and over-resuscitation (leading to complications like compartment syndrome or ARDS). *CVP* - **Central venous pressure (CVP)** is generally not a reliable indicator for guiding fluid resuscitation in burn patients due to its poor correlation with cardiac output and tissue perfusion in this specific patient population. - Changes in CVP can be influenced by many factors, including intrathoracic pressure and right ventricular function, making it an insensitive marker for systemic fluid status in significant burns. *Urine output* - While **urine output** is an essential parameter for monitoring the adequacy of fluid resuscitation in burn patients *after* initial fluid administration, it is not used to *investigate* or *calculate* the initial fluid requirement. - It serves as a real-time indicator of organ perfusion and helps in titrating fluid rates but does not determine the initial bolus or 24-hour fluid volume. *Blood volume measurement* - **Direct measurement of blood volume** is a complex and often invasive procedure that is not practical or readily available for emergency assessment and initial fluid calculation in burn patients. - It is not a standard method for calculating initial fluid requirements in acute burn care.
Question 2: A dead body is found to have marks like branching of a tree on the front of the chest. The most likely cause of death could be due to:
- A. Lightning injury (Correct Answer)
- B. Road traffic accident
- C. Injuries due to bomb blast
- D. Firearm
Explanation: ***Lightning injury*** - The branching, tree-like marks described are known as **Lichtenberg figures**, which are characteristic cutaneous patterns caused by the passage of high-voltage electrical current, such as during a **lightning strike**. - These transient patterns are believed to be due to dilation of capillaries or arborizing superficial burns, sometimes referred to as ferning. *Road traffic accident* - Injuries from a **road traffic accident** typically include blunt force trauma, lacerations, fractures, and internal organ damage, but they do not produce branching, tree-like skin marks. - The pattern of injury is usually widespread and indicative of impact, shearing, or crushing forces, which is distinct from the described branching marks. *Injuries due to bomb blast* - **Bomb blast injuries** are usually categorized as primary (blast wave), secondary (projectiles), tertiary (body displacement), and quaternary (miscellaneous, e.g., burns, toxic inhalation). They would not typically produce the specific Lichtenberg figures. - While burns can occur, they are usually thermal or chemical burns, not the characteristic superficial dendritic branching marks seen with lightning. *Firearm* - **Firearm injuries** result from projectiles (bullets), leading to entrance wounds, exit wounds (if applicable), and internal organ damage along the bullet's path. - The markings associated with firearms do not include branching, tree-like patterns on the skin; instead, they might show tattooing, stippling, or muzzle imprint with close-range shots.
Question 3: Joule burns are seen in
- A. Thermal Injury
- B. Radiation injury
- C. Lightning
- D. Electrocution (Correct Answer)
Explanation: ***Electrocution*** - **Joule burns** are a characteristic type of burn caused by the direct passage of an **electric current** through the body's tissues during electrocution. - The heat generated by the resistance of tissues to the flow of electric current is responsible for these deep, often internal, burns. *Thermal Injury* - **Thermal burns** are caused by external heat sources like flames, hot liquids, or hot objects, not the direct passage of electricity. - While electrocution can cause thermal damage, the specific term "Joule burns" refers to the internal resistive heating from current flow. *Radiation injury* - **Radiation injuries** result from exposure to radiation, such as **UV light**, **X-rays**, or radioactive materials, leading to cellular damage. - They present with distinct features like **radiodermatitis** and are not primarily characterized by resistive heating of tissues. *Lightning* - **Lightning strikes** can cause electrical injuries, but they are a specific type of **high-voltage electrical injury** with unique patterns like **Lichtenberg figures**. - While lightning involves electricity, the term "Joule burns" typically refers more broadly to burns from industrial or domestic electrical currents, highlighting the resistive heating effect.
Question 4: 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 5: Type of shock seen in burn cases:
- A. Neurogenic
- B. Cardiogenic
- C. Hypovolemic (Correct Answer)
- D. None of the options
Explanation: ***Hypovolemic*** - Extensive burns lead to significant **fluid loss** from the damaged capillary beds and surface of the wound. - This loss of plasma and extravascular fluid reduces **intravascular volume**, leading to hypovolemic shock. *Neurogenic* - Neurogenic shock results from **spinal cord injury** causing loss of sympathetic tone and widespread vasodilation. - It is not directly caused by the tissue damage and fluid loss associated with burns. *Cardiogenic* - Cardiogenic shock occurs due to the **heart's inability to pump enough blood**, often from myocardial infarction or severe heart failure. - While burns can indirectly affect cardiac function, the primary shock mechanism is not cardiac pump failure itself. *None of the options* - This option is incorrect because **hypovolemic shock** is a well-established and common type of shock observed in burn cases.
Question 6: Which of the following statements regarding thermal injury is correct?
- A. In child below 5 years, genitals form 1% of area
- B. Lund-Browder chart is the most accurate method for estimating TBSA in children (Correct Answer)
- C. Rule of nines is more accurate than Lund-Browder chart in children
- D. Burn index is the standard clinical method for assessing burn severity
Explanation: ***Lund-Browder chart is the most accurate method for estimating TBSA in children*** - The Lund-Browder chart is the **most accurate method** for estimating the **total body surface area (TBSA)** affected by burns, especially in children, due to its ability to adjust for age-related body proportion changes. - It assigns different body proportions based on age, making it superior to the Rule of Nines for pediatric patients. - This is the **CORRECT** statement. *Rule of nines is more accurate than Lund-Browder chart in children* - This is **FALSE**. The Rule of Nines is **less accurate in children** because their head and neck comprise a larger percentage of TBSA and their lower limbs a smaller percentage compared to adults. - The Lund-Browder chart is specifically designed to account for age-related differences and is therefore more accurate in pediatric burn assessment. *In child below 5 years, genitals form 1% of area* - While this statement is **technically true**, it is not the **most correct** answer in the context of thermal injury assessment methods. - In both adults and children, the **genitals and perineum** together typically account for **1% of TBSA**. - This is a specific anatomical fact but doesn't address burn assessment methodology, which is the main focus of the question. *Burn index is the standard clinical method for assessing burn severity* - This is **FALSE**. The **Burn Index** is not a commonly used term in standard clinical burn assessment. - Burn severity is assessed by considering both **depth** (superficial, partial-thickness, full-thickness) and **TBSA percentage**, along with other factors like location and patient age, but "Burn Index" is not the standard terminology or method used.
Question 7: A body is discovered with burn marks as shown in the image, resembling a 'crocodile skin' pattern. What is the most likely cause?
- A. Chemical burns
- B. High voltage electrical burns (Correct Answer)
- C. Scald burns
- D. Radiation burns
Explanation: ***High voltage electrical burns*** - **High voltage electrical burns** can cause severe damage, including charring and deep tissue necrosis, which can result in a contracted, leathery skin appearance often described as **"crocodile skin"** or **alligator hide**. - The alternating current (AC) associated with high voltage can lead to muscle tetany, causing the victim to clench onto the source, prolonging exposure and increasing the severity of damage and the characteristic burn pattern. *Chemical burns* - Chemical burns result from exposure to corrosive substances and typically manifest as **discoloration**, **blistering**, or **deep tissue damage** depending on the agent and duration of contact. - While severe, chemical burns usually do not produce the specific "crocodile skin" pattern of extensive charring and contraction seen with high voltage electricity. *Scald burns* - Scald burns are caused by hot liquids or steam and commonly result in **blistering**, **redness**, and superficial to partial-thickness skin damage without the deep tissue charring. - The pattern of injury would typically be distinct from the described "crocodile skin," often showing flowing or splash patterns. *Radiation burns* - Radiation burns occur due to exposure to high doses of radiation and can lead to **erythema**, **blistering**, and **skin breakdown** over time. - These burns develop progressively and often have a characteristic delayed presentation and pattern related to the radiation field, not the immediate charring seen with electrical injuries.
Question 8: A 56-year-old male is burned while sleeping in his home. His right upper and lower extremity and the anterior chest have extensive second-degree burns. What is the total percentage of body surface area affected? Reference: Rule of Nines for Adults - Each arm: 9% - Head: 9% - Anterior trunk: 18% - Posterior trunk: 18% - Each leg: 18% - Total: 99%
- A. 10%
- B. 20%
- C. 40% (Correct Answer)
- D. 30%
Explanation: ***40%*** - The **Rule of Nines** is used to estimate the percentage of total body surface area (TBSA) affected by burns in adults. - **Right upper extremity** (entire arm): 9% - **Right lower extremity** (entire leg): 18% - **Anterior chest**: The burn involves a significant portion of the anterior trunk, accounting for approximately 13% (more than half of the 18% anterior trunk) - **Total**: 9% + 18% + 13% = **40%** - This patient has a major burn requiring fluid resuscitation and likely transfer to a burn center. *10%* - This percentage is far too low for the described burn distribution, which includes an entire arm and an entire leg alone (27% combined). - A 10% burn would typically involve only one arm or the head. *20%* - This percentage significantly underestimates the extent of injury. - This would represent approximately one arm (9%) plus one leg (18%), but fails to account for the anterior chest burns. *30%* - While closer, 30% still underestimates the total body surface area affected. - This would account for the arm (9%) and leg (18%) but significantly underestimates the extent of anterior chest involvement described in the scenario.
Question 9: A body shows petechial hemorrhages in the eyes. What is the most likely cause?
- A. Drowning
- B. Poisoning
- C. Strangulation (Correct Answer)
- D. Burns
Explanation: ***Strangulation*** - **Petechial hemorrhages** in the eyes (especially the conjunctiva) and face are highly characteristic of **manual or ligature strangulation**. - These hemorrhages result from increased **venous pressure** and rupture of small capillaries due to compression of blood vessels in the neck. *Drowning* - While fluid in the airways and lungs is a primary finding, **petechial hemorrhages** in the eyes are not a typical or specific sign of drowning. - Absence of specific injuries to the neck or face differentiates it from strangulation. *Poisoning* - The findings in **poisoning** are highly variable depending on the substance, but **petechial hemorrhages** in the eyes are not a common or specific indicator. - Diagnosis typically involves **toxicological analysis** to identify the agent. *Burns* - **Burns** cause tissue damage through heat, electrical, or chemical mechanisms, primarily leading to skin lesions and internal organ damage. - **Petechial hemorrhages** in the conjunctiva are not directly associated with burn injuries.
Question 10: Which part of brain shows consistent changes in heat stroke
- A. Hippocampus
- B. Purkinje cells (Correct Answer)
- C. Midbrain
- D. Cerebral cortex
Explanation: ***Purkinje cells*** - **Purkinje cells** in the cerebellum are particularly vulnerable to **hyperthermia** due to their high metabolic rate and sensitivity to oxidative stress. - Consistent changes, including **necrosis** and **apoptosis**, are often observed in these cells during heat stroke. *Hippocampus* - While the **hippocampus** can be affected in severe heat stroke, showing neuronal damage, it is **not as consistently or uniquely vulnerable** as Purkinje cells. - Damage to the hippocampus is often associated with more generalized **hypoxic-ischemic injury** seen in severe cases. *Midbrain* - The **midbrain** is part of the brainstem and primarily responsible for functions like motor control, vision, and hearing, and typically shows **less consistent or specific damage** in heat stroke compared to Purkinje cells. - Injury to the midbrain during heat stroke is usually a consequence of **widespread cerebral edema** or global anoxia, rather than a primary effect of hyperthermia. *Cerebral cortex* - Damage to the **cerebral cortex** in heat stroke can occur, leading to cognitive dysfunction and seizures, but it is **not as consistently affected** across all cases as Purkinje cells. - Cortical damage is more often linked to severe and prolonged hyperthermia or secondary complications like **cerebral edema**.
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