Trauma — MCQs

Trauma Indian Medical PG Practice Questions and MCQs

Question 141: Which condition builds within the hemithorax, resulting in a collapsed lung, flattened diaphragm, contralateral mediastinal shift, and compromised venous return to the right side of the heart?

A. Open pneumothorax
B. Flail chest
C. Massive pulmonary hemorrhage
D. Tension pneumothorax (Correct Answer)

Explanation: ### Explanation **Correct Answer: D. Tension Pneumothorax** **Mechanism:** A tension pneumothorax occurs when a "one-way valve" mechanism develops, allowing air to enter the pleural space during inspiration but preventing its escape during expiration. This leads to a progressive accumulation of positive pressure within the hemithorax. * **Lung Collapse:** The rising intrapleural pressure exceeds atmospheric pressure, causing the ipsilateral lung to collapse. * **Mediastinal Shift:** The pressure pushes the mediastinum toward the contralateral (opposite) side. * **Hemodynamic Compromise:** The most critical effect is the compression of the low-pressure superior and inferior vena cavae. This reduces venous return to the right atrium, leading to decreased cardiac output and obstructive shock. **Why Incorrect Options are Wrong:** * **A. Open Pneumothorax:** Also known as a "sucking chest wound," air moves freely in and out of the pleural space through a chest wall defect. While it impairs ventilation, it rarely builds the positive pressure required to shift the mediastinum or compromise venous return. * **B. Flail Chest:** Defined by $\geq$3 ribs fractured in $\geq$2 places, causing paradoxical chest wall movement. The primary issue is pulmonary contusion and pain-induced splinting, not positive pressure buildup. * **C. Massive Pulmonary Hemorrhage:** While life-threatening, it typically presents with airway obstruction or hemorrhagic shock. It does not create the "tension" effect on the mediastinum seen with trapped air. **High-Yield Clinical Pearls for NEET-PG:** * **Diagnosis:** Tension pneumothorax is a **clinical diagnosis**. Do NOT wait for an X-ray if the patient is hemodynamically unstable (hypotension, JVD, absent breath sounds). * **Classic Triad:** Hypotension, jugular venous distension (JVD), and absent breath sounds on the affected side. * **Immediate Management:** Needle decompression. According to ATLS 10th edition, the preferred site is the **5th intercostal space, anterior to the mid-axillary line** (the 2nd ICS at the mid-clavicular line is an alternative). * **Definitive Treatment:** Insertion of a chest tube (Tube Thoracostomy).

Question 142: A displaced, unfavorable fracture in the mandibular angle region is a potentially difficult fracture to treat because of?

A. Injury to the neurovascular bundle
B. Malocclusion secondary to injury
C. Distraction of fracture segments by muscle pull (Correct Answer)
D. Increased density of bone in this region of the mandible

Explanation: ### Explanation The classification of mandibular angle fractures as **"favorable"** or **"unfavorable"** is determined by the direction of the fracture line in relation to the **masseter, medial pterygoid, and temporal muscles**. **1. Why Option C is Correct:** In an **unfavorable fracture**, the fracture line runs from the alveolar margin downward and forward. The powerful elevator muscles (masseter, medial pterygoid, and temporalis) are attached to the posterior segment (the ramus), while the depressor muscles (suprahyoids) pull the anterior segment downward. Because the fracture line does not "lock" the segments together, the muscle pull causes **distraction (displacement)** of the fragments. This makes reduction difficult and often necessitates internal fixation. **2. Analysis of Incorrect Options:** * **Option A:** While the inferior alveolar nerve runs through the mandible, its injury causes sensory loss but does not define the mechanical difficulty of treating an unfavorable fracture. * **Option B:** Malocclusion is a *result* of the fracture and displacement, not the primary anatomical reason why an angle fracture is classified as "unfavorable" or difficult to stabilize. * **Option C:** Bone density is actually lower in the angle region compared to the symphysis, and the presence of the third molar further weakens this area, making it a common site for fractures. **Clinical Pearls for NEET-PG:** * **Favorable Fracture:** The fracture line is oriented such that muscle pull tends to draw the fragments together (self-reducing). * **Weakest point of Mandible:** The **condylar neck** is the most common site of fracture, but the **angle** is the most common site when impacted third molars are present. * **Champy’s Lines:** Ideal lines of osteosynthesis used for miniplate fixation in mandibular fractures.

Question 143: What percentage of pneumothorax requires operative management?

A. >10%
B. >20% (Correct Answer)
C. >30%
D. >40%

Explanation: **Explanation:** The management of a pneumothorax is primarily determined by the size of the collapse and the clinical stability of the patient. In surgical practice and trauma protocols (ATLS guidelines), a pneumothorax is generally classified as small or large based on the distance between the chest wall and the visceral pleural line. **Why >20% is correct:** A pneumothorax involving **>20% of the lung volume** is the traditional threshold where spontaneous resolution is unlikely to occur at an adequate rate. At this size, the reduction in vital capacity often leads to clinical symptoms (dyspnea, hypoxia). Therefore, operative management—typically in the form of a **Tube Thoracostomy (Intercostal Drainage)**—is indicated to re-expand the lung and prevent progression to a tension pneumothorax. **Analysis of Incorrect Options:** * **A. >10%:** Small pneumothoraces (<15-20%) in a stable, non-ventilated patient can often be managed conservatively with observation and supplemental oxygen (which hastens nitrogen absorption). * **C & D. >30% and >40%:** While these definitely require intervention, they are not the *minimum* threshold. Waiting until 30-40% collapse increases the risk of respiratory failure and tension physiology unnecessarily. **High-Yield Clinical Pearls for NEET-PG:** * **Initial Management:** For a small, asymptomatic pneumothorax (<20%), observation and 100% O2 is the first step. * **Gold Standard Diagnosis:** While Chest X-ray (Erect, Expiratory film) is common, **Bedside Ultrasound (eFAST)** is more sensitive for detecting occult pneumothorax in trauma (look for the absence of "lung sliding"). * **Tube Insertion Site:** The current ATLS 10th edition recommends the **5th intercostal space**, anterior to the mid-axillary line. * **Tension Pneumothorax:** This is a **clinical diagnosis**. Do not wait for an X-ray; perform immediate needle decompression in the 5th ICS (adults) or 2nd ICS (pediatrics) at the mid-axillary line.

Question 144: Intracranial tension is decreased by all of the following methods EXCEPT?

A. ICT monitoring (Correct Answer)
B. Craniotomy
C. Tumor removal
D. CSF removal

Explanation: **Explanation:** The management of increased intracranial pressure (ICP) is a critical aspect of neurosurgery and trauma care. The core principle involves the **Monro-Kellie Doctrine**, which states that the cranial vault is a fixed volume containing brain tissue, blood, and cerebrospinal fluid (CSF). To decrease pressure, the volume of one of these components must be reduced, or the vault itself must be expanded. **Why Option A is the correct answer:** **ICT (Intracranial Tension) monitoring** is a **diagnostic and observational tool**, not a therapeutic intervention. While it provides real-time data (via intraventricular catheters or intraparenchymal bolts) to guide treatment decisions, the act of monitoring itself does not physiologicaly reduce the pressure within the skull. **Why the other options are incorrect:** * **Craniotomy (and Decompressive Craniectomy):** These surgical procedures involve removing a portion of the skull, effectively increasing the available volume for the brain to expand, thereby directly decreasing ICP. * **Tumor removal:** This addresses the "mass effect." By removing an space-occupying lesion (pathological brain tissue), the total volume within the rigid skull is reduced, lowering the pressure. * **CSF removal:** This is often done via an External Ventricular Drain (EVD). Reducing the volume of the CSF component is one of the fastest ways to alleviate intracranial hypertension. **NEET-PG High-Yield Pearls:** * **Normal ICP:** 5–15 mmHg. Treatment is usually initiated when ICP >20–22 mmHg. * **Cushing’s Triad (Sign of impending herniation):** Hypertension (with widened pulse pressure), Bradycardia, and Irregular respirations. * **First-line Medical Management:** Head elevation (30°), hyperventilation (induces vasoconstriction), and osmotic diuretics (Mannitol or Hypertonic saline). * **Gold Standard Monitoring:** Intraventricular catheter (allows for both monitoring and therapeutic CSF drainage).

Question 145: Which sign is found in splenic injury?

A. Splenic injury (Correct Answer)
B. Perforative peritonitis
C. Mesenteric vascular occlusion
D. Gastric volvulus

Explanation: **Explanation:** The question refers to **Kehr’s Sign**, a classic clinical finding associated with **splenic injury**. **1. Why Splenic Injury is Correct:** Kehr’s sign is defined as **referred pain in the left shoulder** caused by the presence of blood or irritants in the peritoneal cavity. In the context of splenic rupture, blood accumulates under the left diaphragm, irritating the **phrenic nerve (C3-C5)**. Since the supraclavicular nerves (which supply the shoulder) share the same nerve roots (C3, C4), the brain perceives the pain as originating from the shoulder. It is most prominent when the patient is in the Trendelenburg position or when the left upper quadrant is palpated. **2. Why Other Options are Incorrect:** * **Perforative Peritonitis:** While this causes generalized abdominal rigidity and guarding (and occasionally shoulder pain if air collects under the diaphragm), it is not the classic association for Kehr’s sign. * **Mesenteric Vascular Occlusion:** This typically presents with "pain out of proportion to physical findings" and metabolic acidosis, rather than specific referred shoulder pain. * **Gastric Volvulus:** This is characterized by **Borchardt’s Triad** (epigastric pain, inability to vomit, and inability to pass a nasogastric tube), not Kehr’s sign. **3. NEET-PG High-Yield Pearls:** * **Ballance’s Sign:** Fixed dullness in the left flank and shifting dullness in the right flank (indicative of splenic hematoma/rupture). * **Organ Involvement:** The spleen is the **most commonly injured organ** in blunt abdominal trauma. * **Investigation of Choice:** **CECT Abdomen** is the gold standard for hemodynamically stable patients; **FAST** is used for unstable patients. * **Grading:** Splenic injuries are graded I–V using the AAST scale; Grade V represents a completely shattered spleen or hilar vascular injury.

Question 146: Which of the following statements about flail chest is FALSE?

A. Involves 3 or more contiguous ribs in at least 2 locations
B. Chest wall moves inwards during inspiration
C. Mechanical ventilation is always needed (Correct Answer)
D. Can lead to respiratory failure

Explanation: ### Explanation **1. Why Option C is the Correct (False) Statement:** The management of flail chest has evolved from mandatory "internal splinting" with mechanical ventilation to a more conservative, patient-centric approach. **Mechanical ventilation is NOT always needed.** The primary goal is to ensure adequate oxygenation and prevent pneumonia. If a patient has good pain control (e.g., epidural analgesia) and can maintain oxygenation with supplemental oxygen and chest physiotherapy, they can be managed without a ventilator. Intubation is reserved for patients with respiratory failure (PaO₂ < 60 mmHg), severe head injury, or shock. **2. Analysis of Other Options:** * **Option A (True):** This is the classic anatomical definition. A flail segment occurs when **3 or more contiguous ribs** are fractured in **at least 2 places**, creating a segment that is detached from the rest of the thoracic cage. * **Option B (True):** This describes **paradoxical respiration**. During inspiration, the negative intrathoracic pressure sucks the unstable flail segment **inwards**, while the rest of the chest expands. During expiration, the segment moves outwards. * **Option D (True):** Respiratory failure in flail chest is primarily caused by the underlying **pulmonary contusion** (leading to V/Q mismatch) and pain-induced splinting (leading to atelectasis), rather than the paradoxical movement itself. **3. High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of hypoxia:** Underlying pulmonary contusion (not the rib fractures). * **Initial Management:** Humidified oxygen and **aggressive pain control** (Epidural analgesia is the gold standard). * **Indications for Surgery (ORIF):** Failure to wean from the ventilator, severe chest wall deformity, or persistent pain. * **Radiology:** Flail chest is a **clinical diagnosis**, though X-rays/CT scans are used to identify the number of fractures and associated contusions.

Question 147: In a patient with burns, which of the following statements is true?

A. Carbon monoxide is highly toxic to the pulmonary tract. (Correct Answer)
B. Early tracheostomy is indicated because it is difficult to pass a tube through an inflamed pharynx.
C. Laryngeal edema can occur as late as 48 hours.
D. None of the above.

Explanation: ### Explanation **1. Why Option A is Correct:** Carbon monoxide (CO) is a major component of smoke inhalation injury. It is highly toxic because its affinity for hemoglobin is **200–250 times greater** than that of oxygen. This leads to the formation of carboxyhemoglobin, causing a leftward shift of the oxyhemoglobin dissociation curve and profound tissue hypoxia. Furthermore, CO binds to mitochondrial cytochrome oxidase, interfering with cellular respiration. While it doesn't cause direct "chemical" mucosal burns like steam, its systemic toxicity and role in pulmonary dysfunction make it the primary toxin in inhalation injuries. **2. Why Other Options are Incorrect:** * **Option B:** Early tracheostomy is **not** routinely indicated. The preferred management for impending airway obstruction in burn patients is **early endotracheal intubation**. Tracheostomy in burn patients is associated with higher rates of sepsis and stomal complications; it is reserved for patients requiring prolonged ventilation where intubation is no longer feasible. * **Option C:** Laryngeal edema typically develops rapidly due to the rich vascularity of the upper airway. It usually peaks within **8 to 24 hours** post-injury. Waiting 48 hours is dangerous, as the window for safe intubation may have passed due to massive swelling. **3. NEET-PG High-Yield Clinical Pearls:** * **Gold Standard for Diagnosis:** Fiberoptic bronchoscopy is the gold standard for diagnosing inhalation injury (looking for soot, edema, or ulceration). * **Cherry Red Skin:** A classic but rare sign of CO poisoning; more commonly, the patient appears cyanotic or pale. * **Pulse Oximetry Pitfall:** Standard pulse oximetry cannot distinguish between oxyhemoglobin and carboxyhemoglobin, often giving **falsely normal SpO2 readings** in CO poisoning. * **Treatment:** The half-life of CO is reduced from 4 hours (room air) to 40–60 minutes by administering **100% humidified oxygen**.

Question 148: Compression osteosynthesis heals fracture mandible by which mechanism?

A. Primary union without callus formation (Correct Answer)
B. Secondary union without callus formation
C. Compression union
D. All of the above

Explanation: **Explanation:** The core concept behind **Compression Osteosynthesis** (achieved via compression plates and screws) is the provision of **absolute stability**. When a fracture is rigidly fixed and the bone ends are compressed together, the interfragmentary strain is reduced to near zero. 1. **Why Option A is correct:** Under conditions of absolute stability, **Primary (Direct) Bone Healing** occurs. This mechanism involves "contact healing" or "gap healing" where Haversian remodeling occurs directly across the fracture site via **cutting cones** (osteoclasts followed by osteoblasts). Because there is no movement between fragments, there is no stimulus for the formation of a periosteal bridge; thus, it heals **without callus formation**. 2. **Why Option B is incorrect:** Secondary union is the natural process of bone healing characterized by the formation of a **callus**. It occurs under conditions of relative stability (e.g., casts, intramedullary nails, or external fixators). It is impossible to have secondary union without a callus. 3. **Why Option C is incorrect:** "Compression union" is a descriptive term for the state of the bone but is not a recognized physiological mechanism of histological bone healing. **High-Yield Clinical Pearls for NEET-PG:** * **Primary Healing:** Requires absolute stability + compression. No callus. (Example: Compression plating). * **Secondary Healing:** Requires relative stability + micromotion. Callus formation present. (Example: Gunning splints, MMM, or IM nails). * **Mandible Specifics:** The goal of rigid internal fixation (RIF) in the mandible is early mobilization and restoration of occlusion. * **Champy’s Technique:** Uses non-compression miniplates placed along the "ideal lines of osteosynthesis" to neutralize tension forces.

Question 149: A 45-year-old man has a skull fracture of the temporal bone. What is the most likely complication?

A. Diffuse axonal injury
B. Acute extradural hematoma (Correct Answer)
C. Acute subdural hematoma
D. Tentorial herniation

Explanation: ### Explanation **Correct Option: B. Acute Extradural Hematoma (EDH)** The temporal bone is the thinnest part of the skull. Directly underlying the squamous portion of the temporal bone (at the **Pterion**) lies the **Middle Meningeal Artery (MMA)**. A fracture in this region frequently lacerates the MMA, leading to an accumulation of blood between the inner table of the skull and the dura mater. This is the classic mechanism for an Acute Extradural Hematoma. On CT, this appears as a characteristic **biconvex (lentiform)** hyperdensity. **Why other options are incorrect:** * **A. Diffuse Axonal Injury (DAI):** This is caused by high-velocity rotational acceleration/deceleration forces (shearing injury), not typically by a focal skull fracture. It presents with immediate coma and "starfield" patterns on MRI. * **C. Acute Subdural Hematoma (SDH):** This usually results from the tearing of **bridging veins** between the cortex and dural sinuses. While it can occur with trauma, it is not specifically linked to temporal bone fractures like EDH is. * **D. Tentorial Herniation:** This is a *sequela* (complication) of any significant mass effect (like a large EDH or SDH), but it is not the direct or most likely primary complication of the fracture itself. **High-Yield Clinical Pearls for NEET-PG:** * **Lucid Interval:** Classically associated with EDH (patient regains consciousness before deteriorating again). * **Source of Bleed:** MMA is the most common source; however, in children, EDH can occur from dural sinus tears or diploic veins without a fracture. * **CT Finding:** EDH does *not* cross suture lines (as the dura is firmly attached there) but can cross the midline. * **Management:** Urgent craniotomy and evacuation if the volume is >30 cm³ or GCS <9 with pupillary changes.

Question 150: What is the recommended re-implantation time for a lower limb?

A. 6 hours
B. 4 hours
C. 8 hours (Correct Answer)
D. 10 hours

Explanation: **Explanation:** The success of limb re-implantation depends primarily on the **warm ischemia time**—the duration the tissue survives without blood supply at room temperature. The correct answer is **8 hours** for the lower limb because muscle tissue is highly sensitive to hypoxia. **1. Why 8 hours is correct:** Lower limbs contain large muscle masses (e.g., quadriceps, gastrocnemius). Skeletal muscle begins to undergo irreversible necrosis after **6 to 8 hours** of warm ischemia. Beyond this window, re-establishing blood flow can lead to **Reperfusion Injury** and **Crush Syndrome**, causing systemic complications like hyperkalemia, metabolic acidosis, and myoglobinuria-induced acute renal failure. Therefore, 8 hours is considered the upper limit for a viable attempt. **2. Analysis of Incorrect Options:** * **6 hours:** While 6 hours is the ideal "golden period" to minimize complications, it is not the absolute recommended limit for the lower limb. * **4 hours:** This is too conservative. While faster is always better, re-implantation is still viable beyond 4 hours. * **10 hours:** This exceeds the safe threshold for muscle survival. Re-implanting a large muscle mass after 10 hours of warm ischemia carries a high risk of life-threatening systemic toxicity and gangrene. **Clinical Pearls for NEET-PG:** * **Warm vs. Cold Ischemia:** Cold ischemia (storing the part at 4°C) can extend the window significantly—up to **12 hours** for parts with muscle (major replants) and up to **24 hours** for digits (minor replants). * **Digits vs. Limbs:** Digits contain no muscle, only bone, tendon, and skin; thus, they tolerate ischemia much better than the lower limb. * **Storage Protocol:** Wrap the amputated part in saline-soaked gauze, place it in a plastic bag, and then place that bag in a container of **ice water** (do not let the tissue touch ice directly to avoid frostbite).

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