Trauma Practice Questions

Q: Which one of the following electrolyte abnormalities will be present in a patient who has suffered burns over 56% of his body?

Hyperkalemic acidosis. In a patient with major burns (56% Total Body Surface Area), the primary electrolyte and acid-base disturbance is **Hyperkalemic Acidosis**. ### **Why Hyperkalemic Acidosis is Correct:** 1. **Hyperkalemia:** Major burns cause extensive thermal destruction of cells (cytolysis). Since Potassium ($K^+$) is the primary intracellular cation, the rupture of cell membranes releases massive amounts of $K^+$ into the extracellular fluid. Additionally, impaired renal perfusion due to hypovolemic shock reduces $K^+$ excretion. 2. **Metabolic Acidosis:** Burn injury leads to hypovolemia and decreased tissue perfusion, resulting in anaerobic metabolism and the accumulation of **lactic acid**. Furthermore, in acidosis, the body attempts to buffer excess hydrogen ions ($H^+$) by moving them into cells in exchange for $K^+$ moving out, further exacerbating the hyperkalemia. ### **Why Other Options are Incorrect:** * **Hyperkalemic Alkalosis:** Alkalosis typically causes *hypokalemia* as $K^+$ shifts into cells to allow $H^+$ to move out into the serum. * **Hypokalemic Acidosis/Alkalosis:** While hypokalemia can occur in the *late* diuretic phase of burn recovery (due to fluid resuscitation and renal excretion), the immediate and most life-threatening acute phase abnormality is hyperkalemia. ### **NEET-PG High-Yield Pearls:** * **Early Phase (0-48h):** Hyperkalemia, Hyponatremia (due to shift into interstitium), and Metabolic Acidosis. * **Late Phase (>48h):** Hypokalemia (due to diuresis) and Hypoproteinemia. * **Gold Standard for Fluid Resuscitation:** Parkland Formula ($4 \text{ ml} \times \text{kg} \times \% \text{TBSA}$). * **Indicator of Adequate Resuscitation:** Urine output ($0.5\text{--}1 \text{ ml/kg/hr}$ in adults).

Q: A 24-year-old patient has sustained a third-degree burn of the right upper limb, second-degree burns of the right lower limb, and a first-degree burn of the entire back. What is the total percentage of the body surface area affected by the burns?

27%. The correct answer is **27%**. This question tests your ability to apply the **Wallace Rule of Nines** while understanding which types of burns are included in the Total Body Surface Area (TBSA) calculation. ### 1. Why Option A is Correct To calculate TBSA for fluid resuscitation (e.g., Parkland Formula), we **only include second-degree (partial-thickness) and third-degree (full-thickness) burns.** First-degree burns (erythema only) are excluded. Using the Rule of Nines: * **Right Upper Limb (Third-degree):** 9% * **Right Lower Limb (Second-degree):** 18% * **Entire Back (First-degree):** 0% (Excluded from calculation) * **Total:** 9% + 18% = **27%** ### 2. Why Other Options are Incorrect * **Option B (36%):** This would be the result if the entire back (18%) was included but the arm was excluded, or if the arm and half the back were included. * **Option C (45%):** This is the result if you incorrectly include the first-degree burns on the back (27% + 18% = 45%). * **Option D (54%):** This overestimates the surface area significantly, likely by doubling the limb values. ### 3. Clinical Pearls for NEET-PG * **Rule of Nines (Adults):** Head & Neck (9%), Each Upper Limb (9%), Each Lower Limb (18%), Anterior Trunk (18%), Posterior Trunk (18%), Perineum (1%). * **Lund and Browder Chart:** The most accurate method for TBSA calculation, especially in **pediatrics**, as it accounts for changes in body proportions with age. * **Palmar Method:** The patient’s palm (including fingers) represents approximately **1% TBSA**; useful for small or patchy burns. * **Fluid Resuscitation:** Remember that the Parkland Formula ($4 \text{ mL} \times \text{kg} \times \% \text{TBSA}$) uses the TBSA calculated here. Including first-degree burns leads to dangerous over-resuscitation (fluid creep).

Q: What does the return of the bulbocavernous reflex signify in the context of spinal shock?

A sign of recovery from spinal shock. ### Explanation **Concept Overview:** Spinal shock is a state of transient physiological reflex depression following an acute spinal cord injury. It is characterized by the loss of all sensorimotor functions and autonomic reflexes below the level of the lesion. The **Bulbocavernous Reflex (BCR)**—elicited by squeezing the glans penis or tugging on a Foley catheter while palpating the anal sphincter for contraction—is one of the first spinal reflexes to return as spinal shock resolves. **Why Option A is Correct:** The return of the BCR marks the **end of spinal shock**. It signifies that the spinal cord segments below the level of injury have regained their reflex arc activity, even if they remain disconnected from the brain. Until the BCR returns, a clinician cannot accurately determine the true extent of the neurological deficit (complete vs. incomplete). **Why Other Options are Incorrect:** * **Options B, C, and D:** The return of the BCR does **not** indicate the severity or type of the lesion (partial, complete, or incomplete). It only confirms that the "shock" phase is over. Once the BCR is present, any remaining sensory or motor deficit is then considered permanent or representative of the actual cord injury. For example, if the BCR has returned but there is still no motor or sensory function, the injury is classified as a **complete** spinal cord injury. **NEET-PG High-Yield Pearls:** * **First reflex to return:** Bulbocavernous reflex (usually within 24–48 hours). * **First sign of recovery from spinal shock:** Return of the BCR. * **Definition of Spinal Shock:** Total loss of reflexes, motor, and sensory function (flaccid paralysis). * **Neurogenic Shock vs. Spinal Shock:** Do not confuse the two. Neurogenic shock is a **hemodynamic** phenomenon (hypotension + bradycardia) due to loss of sympathetic tone, whereas spinal shock is a **neurological** phenomenon (loss of reflexes).

Q: An ulcer that may develop in burn tissue is called?

Marjolin's ulcer. **Explanation:** **Marjolin’s Ulcer (Correct Answer):** A Marjolin’s ulcer is a **Squamous Cell Carcinoma (SCC)** that arises in areas of chronic inflammation, long-standing scars, or non-healing wounds. It is most classically associated with **old burn scars** (cicatrix). The underlying mechanism involves chronic irritation and poor lymphatic drainage in the scar tissue, leading to malignant transformation. These ulcers are typically aggressive, have everted edges, and carry a higher risk of metastasis compared to SCC arising in healthy skin. **Analysis of Incorrect Options:** * **Rodent Ulcer:** This is a clinical term for **Basal Cell Carcinoma (BCC)**. It typically occurs on sun-exposed areas (above the line joining the tragus to the angle of the mouth) and is characterized by a pearly rolled-out border and slow local invasion. It is not specifically associated with burn scars. * **Melanoma:** This is a malignancy of melanocytes. While it can occur anywhere on the skin, it is not a characteristic complication of chronic burn scars. * **Curling’s Ulcer:** This is an **acute gastric erosion/ulcer** resulting from severe burns (hypovolemia leads to reduced mucosal blood flow). While it is associated with burns, it occurs in the **gastrointestinal tract**, not the burn tissue itself. **High-Yield Clinical Pearls for NEET-PG:** * **Latency Period:** Marjolin’s ulcer usually develops 20–30 years after the initial burn injury. * **Biopsy:** Any ulcer developing in a chronic scar that shows new growth, bleeding, or induration must undergo biopsy to rule out malignancy. * **Treatment:** Wide local excision (usually with 2 cm margins) is the treatment of choice; lymph node dissection is indicated if nodes are palpable. * **Prognosis:** Marjolin’s ulcers are more aggressive than standard SCC because the scar tissue lacks protective lymphatics, allowing for late but rapid spread once the basement membrane is breached.

Question 1

Which one of the following electrolyte abnormalities will be present in a patient who has suffered burns over 56% of his body?

Accepted Answer

Hyperkalemic acidosis

Answer

Hyperkalemic alkalosis

Answer

Hypokalemic acidosis

Answer

Hypokalemic alkalosis

Question 2

Which of the following is the first line of defense in coagulopathic hemorrhage?

Accepted Answer

Fresh frozen plasma

Answer

Packed red cells

Answer

Cryoprecipitate

Answer

Platelets

Question 3

A 24-year-old patient has sustained a third-degree burn of the right upper limb, second-degree burns of the right lower limb, and a first-degree burn of the entire back. What is the total percentage of the body surface area affected by the burns?

Accepted Answer

27%

Answer

36%

Answer

45%

Answer

54%

Question 4

The cold water treatment of burns has the disadvantage that it increases the chances of which of the following?

Accepted Answer

Infection

Answer

Pain

Answer

Exudation

Answer

None of the above

Question 5

A patient with an unfavorable fracture of the angle of the mandible is best treated by:

Accepted Answer

Open reduction with bone plate fixation

Answer

Closed reduction with intermaxillary fixation (IMF)

Answer

Closed reduction with cap splint

Answer

Circum mandibular wiring

Question 6

All of the following are ominous signs in a case of severe head injury, EXCEPT:

Accepted Answer

Development of diabetes insipidus

Answer

Anisocoria

Answer

Decoicate posturing

Answer

Decerebrate posturing

Question 7

What does the return of the bulbocavernous reflex signify in the context of spinal shock?

Accepted Answer

A sign of recovery from spinal shock

Answer

A partial lesion of the spinal cord

Answer

A complete transection of the spinal cord

Answer

An incomplete transection of the spinal cord

Question 8

An ulcer that may develop in burn tissue is called?

Accepted Answer

Marjolin's ulcer

Answer

Rodent ulcer

Answer

Melanoma

Answer

Curling's ulcer

Question 9

In a head injury patient, mannitol should not be used for control of increased intracranial pressure when?

Accepted Answer

Serum osmolality is greater than 320 mOsmol/kg

Answer

Arterial PaCO2 is greater than 35 mm Hg

Answer

Arterial PaCO2 is greater than 100 mm Hg

Answer

Arterial pH is 7.4

Question 10

Which of the following is an indication for emergency thoracotomy?

Accepted Answer

Greater than 200 ml of blood drained by chest tube over 3 consecutive hours

Answer

Output of greater than 1 L at the time of intercostal chest tube insertion

Answer

Penetrating chest trauma

Answer

All of the above

Trauma — MCQs

Trauma — MCQs

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