General Surgery Principles — MCQs

General Surgery Principles Indian Medical PG Practice Questions and MCQs

Question 611: The use of 5% dextrose as an intravenous resuscitation fluid can lead to which of the following?

A. Improve cerebral perfusion
B. Provide glucose substrate for cerebral metabolism
C. Reduce intracranial pressure and cause cerebral edema
D. Reduce serum osmolality and cause brain edema (Correct Answer)

Explanation: **Explanation:** The correct answer is **D. Reduce serum osmolality and cause brain edema.** **Why it is correct:** 5% Dextrose (D5W) is technically isotonic in the bag, but once infused, the glucose is rapidly metabolized by cells. This leaves behind "free water," making the solution functionally **hypotonic**. This free water reduces the serum osmolality, creating an osmotic gradient that shifts water from the intravascular space into the intracellular space. In the brain, this leads to cellular swelling and **cerebral edema**, which can dangerously increase intracranial pressure (ICP). Therefore, D5W is strictly contraindicated as a resuscitation fluid, especially in trauma or head injury patients. **Why the other options are wrong:** * **A & B:** While glucose is the primary fuel for the brain, D5W does not improve perfusion. In fact, by causing cerebral edema, it increases ICP, which *decreases* cerebral perfusion pressure (CPP = MAP - ICP). Furthermore, hyperglycemia during acute brain injury can exacerbate neuronal damage via lactic acidosis. * **C:** This is contradictory. Reducing ICP would require a hypertonic solution (like Mannitol or 3% Saline) to draw water *out* of the brain. D5W does the opposite—it increases ICP by causing edema. **High-Yield Clinical Pearls for NEET-PG:** * **Fluid of Choice for Resuscitation:** Isotonic crystalloids (Ringer’s Lactate or Normal Saline) are preferred as they stay in the extracellular compartment. * **The "Free Water" Rule:** 1 liter of D5W provides roughly 1000ml of free water, whereas 1 liter of Normal Saline provides 0ml. * **Indication for D5W:** It is primarily used to treat hypernatremia (to replace a free water deficit) or to provide calories in a non-stressed patient, but never for volume expansion.

Question 612: What is the primary method for preventing surgical wound infection?

A. Preoperative shaving
B. Preoperative antibiotic therapy (Correct Answer)
C. Monofilament sutures
D. Wound apposition

Explanation: ### Explanation The primary method for preventing surgical site infections (SSIs) is the timely administration of **preoperative antibiotic prophylaxis**. **1. Why Preoperative Antibiotic Therapy is Correct:** The goal of prophylaxis is to achieve therapeutic drug levels in the tissues at the exact moment of incision. According to standard guidelines (e.g., SCIP), antibiotics should be administered within **60 minutes before the skin incision** (120 minutes for Vancomycin or Fluoroquinolones). This creates a chemical barrier against skin flora (like *Staphylococcus aureus*) and endogenous bacteria that may be released during the procedure. **2. Why Other Options are Incorrect:** * **Preoperative Shaving:** Shaving with a razor causes microscopic skin abrasions that act as a nidus for bacterial colonization, actually **increasing** the risk of SSI. If hair removal is necessary, **clipping** immediately before surgery is the preferred method. * **Monofilament Sutures:** While monofilament sutures (like PDS or Prolene) have a lower risk of harboring bacteria compared to multifilament/braided sutures (like Silk), they are a technical choice rather than the primary preventive strategy. * **Wound Apposition:** Accurate skin closure (apposition) reduces dead space and promotes healing, but it is a secondary factor compared to the initial bacterial load reduction provided by antibiotics. **3. High-Yield Clinical Pearls for NEET-PG:** * **Timing:** The most critical factor for antibiotic efficacy is administration **before** the incision. * **Duration:** For most clean and clean-contaminated surgeries, a **single dose** is sufficient. Prophylaxis should generally not exceed 24 hours postoperatively. * **Skin Preparation:** Chlorhexidine-alcohol is superior to Povidone-iodine for preoperative skin antisepsis. * **Normothermia & Oxygenation:** Maintaining perioperative body temperature and high inspired oxygen fractions also significantly reduces SSI risk.

Question 613: Which age group typically exhibits the 'best' (least noticeable) scars?

A. Infants
B. Children
C. Adults
D. Very old people (Correct Answer)

Explanation: **Explanation:** The quality of a scar is primarily determined by the skin's tension and the rate of collagen synthesis. **Why 'Very Old People' is correct:** In the elderly, the skin undergoes significant physiological changes, including a loss of elastic fibers and a decrease in subcutaneous fat. This results in **increased skin laxity** and decreased resting skin tension. When tension is low, the wound edges approximate with minimal stress, leading to a fine, linear, and less noticeable scar. Furthermore, the inflammatory response and collagen turnover are slower in older age, which paradoxically prevents the exuberant fibroblastic activity that causes thick or hypertrophic scars. **Why other options are incorrect:** * **Infants and Children:** Young skin is highly elastic and under significant tension. Additionally, children have a very robust inflammatory response and rapid collagen synthesis. This often leads to wider, more prominent, or even hypertrophic scars. * **Adults:** While skin tension begins to decrease compared to childhood, adults still possess enough dermal collagen and tension to produce more visible scars than the elderly. **Clinical Pearls for NEET-PG:** * **Tension is the Enemy:** The single most important local factor in determining scar width is the tension across the wound edges. * **Langer’s Lines:** Incisions made parallel to these relaxed skin tension lines (RSTL) result in the best cosmetic outcomes because they minimize tension. * **Keloids vs. Hypertrophic Scars:** While the elderly have the "best" scars, remember that Keloids (which extend beyond the original wound boundaries) are most common in the 10–30 age group and are rare in the very young or very old.

Question 614: Which of the following is NOT a feature of necrotising fasciitis?

A. Disproportionate pain
B. Erythema limited to the area of oedema (Correct Answer)
C. Dishwater pus
D. Crepitus

Explanation: **Explanation:** Necrotizing Fasciitis (NF) is a life-threatening, rapidly progressive infection of the deep fascia and subcutaneous tissues. The hallmark of NF is that the **internal tissue destruction is far more extensive than what is visible on the skin surface.** **Why Option B is the Correct Answer:** In NF, the infection spreads rapidly along the deep fascial planes, well beyond the margins of superficial skin changes. Therefore, **erythema is NOT limited to the area of edema.** The skin may appear relatively normal or mildly erythematous while the underlying fascia is already necrotic. This "discrepancy" between superficial appearance and deep destruction is a key diagnostic clue. **Analysis of Incorrect Options:** * **A. Disproportionate pain:** This is often the earliest clinical sign. The patient experiences severe, excruciating pain that seems far worse than the visible skin findings (e.g., mild redness). * **C. Dishwater pus:** During surgical exploration, the presence of thin, foul-smelling, grayish-brown fluid (resembling dishwater) is a classic finding indicating liquefactive necrosis of the fascia. * **D. Crepitus:** Caused by gas-forming organisms (Type I NF), crepitus (a crunchy sensation on palpation) is a specific but late sign of the disease. **NEET-PG High-Yield Pearls:** * **LRINEC Score:** Used to distinguish NF from cellulitis (includes CRP, WBC, Hemoglobin, Sodium, Creatinine, and Glucose). * **Finger Test:** A bedside test where a small incision is made under local anesthesia; a positive test shows lack of bleeding, "dishwater" fluid, and easy blunt dissection of the fascia with a finger. * **Management:** The gold standard is **emergency surgical debridement** and broad-spectrum antibiotics. "Life over limb" is the surgical mantra. * **Fournier’s Gangrene:** A specific type of NF involving the perineum and scrotum.

Question 615: What is a Verres needle used for?

A. Creating pneumoperitoneum (Correct Answer)
B. Liver biopsy
C. Bone marrow biopsy
D. Spinal anesthesia

Explanation: The **Verres needle** is a specialized instrument used in laparoscopic surgery to establish **pneumoperitoneum** (insufflation of the abdominal cavity with $CO_2$). ### Why Option A is Correct: The needle features a spring-loaded inner stylet with a blunt tip and a hollow, sharp outer sheath. When pushed through the abdominal wall layers (fascia and peritoneum), the resistance retracts the blunt stylet, allowing the sharp needle to pierce the tissue. Once the needle enters the free peritoneal cavity, the lack of resistance causes the blunt stylet to spring forward, protecting the internal viscera from injury. This "blind" technique is the most common method for initial insufflation. ### Why Other Options are Incorrect: * **B. Liver biopsy:** Typically performed using a **Tru-cut needle** or a Menghini needle. * **C. Bone marrow biopsy:** Performed using a **Salah** or **Jamshidi needle**. * **D. Spinal anesthesia:** Performed using a **Quincke** or **Whitacre needle** to access the subarachnoid space. ### High-Yield Clinical Pearls for NEET-PG: * **Safety Checks:** After insertion, the **Double Click sound**, the **Aspiration test** (no blood/fecal matter), and the **Saline Drop test** (drop should be sucked in by negative intra-abdominal pressure) are used to confirm correct placement. * **Alternative:** The **Hasson technique** is an "open" method for creating pneumoperitoneum, preferred in patients with previous abdominal surgeries to avoid bowel injury. * **Pressure Limit:** Initial insufflation pressure is usually set at **12–15 mmHg**.

Question 616: A 35-year-old patient presents with features of septicemia, including hypotension and low urine output, and is being treated for colonic necrosis. What is the initial management approach?

A. Intravenous fluid resuscitation combined with dopamine infusion.
B. Intravenous fluid resuscitation only. (Correct Answer)
C. Dopamine infusion only.
D. High-dose antibiotics.

Explanation: ### Explanation **Correct Answer: B. Intravenous fluid resuscitation only.** **1. Why Option B is Correct:** The patient is presenting with **Septic Shock** (hypotension and oliguria secondary to colonic necrosis). According to the **Surviving Sepsis Campaign guidelines**, the cornerstone of initial management is aggressive fluid resuscitation. The primary goal is to restore intravascular volume and improve organ perfusion. In the initial stage of shock, hypotension is often "relative" or "absolute" hypovolemia due to vasodilation and capillary leak. Therefore, the first step is a fluid bolus (typically 30 ml/kg of crystalloids) to assess fluid responsiveness before considering vasopressors. **2. Why Other Options are Incorrect:** * **Option A & C:** Vasopressors like **Dopamine** (or the currently preferred Norepinephrine) should never be started in a hypovolemic patient without adequate fluid loading. Starting pressors on an "empty tank" causes intense vasoconstriction, which further compromises tissue perfusion and can worsen organ ischemia (e.g., worsening the colonic necrosis). * **Option D:** While antibiotics are crucial in sepsis, they do not address the immediate hemodynamic instability (hypotension). Resuscitation and stabilization of ABCs (Airway, Breathing, Circulation) always take precedence. **3. NEET-PG High-Yield Pearls:** * **Fluid of Choice:** Isotonic crystalloids (Normal Saline or Ringer’s Lactate) are preferred over colloids. * **First-line Vasopressor:** If hypotension persists despite adequate fluid resuscitation (MAP <65 mmHg), **Norepinephrine** is now the first-line agent of choice, replacing Dopamine. * **Source Control:** In this specific case, once the patient is stabilized, definitive management requires **emergency laparotomy** to remove the necrotic colon (Source Control). * **Early Goal-Directed Therapy (EGDT):** Focuses on maintaining CVP (8–12 mmHg), MAP (≥65 mmHg), and Urine Output (≥0.5 mL/kg/hr).

Question 617: In which condition does the jaw deviate to the same side?

A. TMJ ankylosis
B. Hypoplasia of condyle
C. Subcondylar fractures
D. All of the above (Correct Answer)

Explanation: **Explanation:** The direction of mandibular deviation is a high-yield concept in surgery. The rule of thumb is: **The jaw deviates toward the side of the lesion (affected side)** in conditions involving structural deficiency or mechanical restriction of the Temporomandibular Joint (TMJ). **Why "All of the above" is correct:** The primary muscle responsible for opening the mouth and moving the jaw to the opposite side is the **Lateral Pterygoid**. When one side is weakened or mechanically blocked, the functional lateral pterygoid on the healthy side pushes the mandible toward the diseased/weak side. 1. **TMJ Ankylosis (Option A):** There is a mechanical restriction and fusion of the joint. During opening, the affected side acts as a fixed pivot, causing the mandible to shift toward that side. 2. **Hypoplasia of Condyle (Option B):** Due to the shorter ramus and underdeveloped condyle on the affected side, there is a lack of vertical support and muscle efficiency, leading to deviation toward the hypoplastic side. 3. **Subcondylar Fractures (Option C):** In a unilateral fracture, the pull of the lateral pterygoid muscle is lost on the fractured side. The intact contralateral lateral pterygoid muscle pushes the jaw toward the side of the fracture. **Clinical Pearls for NEET-PG:** * **Deviation vs. Deflection:** *Deviation* refers to a jaw that moves toward one side but returns to the midline at maximum opening (often seen in disc displacement with reduction). *Deflection* refers to the jaw shifting to one side and staying there (seen in ankylosis or fractures). * **Nerve Injury:** In **Hypoglossal nerve (CN XII)** injury, the tongue deviates **toward** the side of the lesion. * **Nerve Injury:** In **Trigeminal nerve (CN V)** motor root injury, the jaw deviates **toward** the side of the lesion (due to lateral pterygoid paralysis). * **Nerve Injury:** In **Vagus nerve (CN X)** injury, the uvula deviates **away** from the side of the lesion.

Question 618: A 26-year-old male presents with a painless swelling over the umbilicus. What is the most probable diagnosis?

A. Omphalitis
B. Umbilical hernia (Correct Answer)
C. Omphalocele
D. Gastroschisis

Explanation: ### **Explanation** The correct answer is **B. Umbilical hernia**. **1. Why Umbilical Hernia is Correct:** In an adult, a painless swelling at the umbilicus is most commonly an **acquired umbilical hernia**. This occurs due to a defect in the linea alba at the umbilical cicatrix. In adults, it is often "para-umbilical," where the protrusion occurs through a weakness just above or below the umbilical ring. The clinical presentation of a soft, reducible, and painless lump that increases with intra-abdominal pressure (like coughing or straining) is classic for this condition. **2. Why Other Options are Incorrect:** * **A. Omphalitis:** This refers to an infection of the umbilical stump. It presents with signs of inflammation such as redness (erythema), warmth, tenderness, and often purulent discharge. It is not a "painless swelling." * **C. Omphalocele:** This is a **congenital** ventral wall defect seen at birth where abdominal contents protrude through the umbilical ring, covered by a peritoneal sac. It is not a diagnosis for a 26-year-old. * **D. Gastroschisis:** This is also a **congenital** defect, typically occurring to the right of the umbilicus, where bowel loops protrude without a covering sac. Like omphalocele, this is diagnosed in neonates, not adults. **3. NEET-PG High-Yield Pearls:** * **Adult vs. Pediatric:** Pediatric umbilical hernias often close spontaneously by age 2; adult umbilical hernias never resolve spontaneously and carry a higher risk of **strangulation** due to the narrow neck of the sac. * **Risk Factors:** In adults, it is associated with conditions that increase intra-abdominal pressure, such as obesity, pregnancy, and ascites (e.g., Cirrhosis—Caput Medusae). * **Mayo’s Operation:** Historically used for repair (vest-over-pants repair), though modern standards prefer tension-free mesh hernioplasty.

Question 619: What is true about compartment syndrome?

A. Common in open lower limb fractures
B. Absence of pulses is an early sign
C. Never seen in open injuries
D. Pain on passive movement (Correct Answer)

Explanation: **Explanation:** Compartment syndrome occurs when increased interstitial pressure within a closed osteofascial compartment compromises local tissue perfusion. **Why Option D is Correct:** **Pain on passive stretching** of the muscles within the affected compartment is the **earliest and most sensitive clinical sign**. This occurs because stretching ischemic muscle fibers triggers intense nociceptive signaling before permanent nerve or muscle damage occurs. **Analysis of Incorrect Options:** * **Option A:** While it can occur in open fractures, it is actually **more common in closed fractures**. In closed injuries, the intact skin and fascia act as a container that traps hematoma and edema, rapidly increasing internal pressure. * **Option B:** **Absence of pulses (Pulselessness) is a late and ominous sign.** Since the intracompartmental pressure required to cause ischemia is usually lower than systolic arterial pressure, the distal pulse often remains palpable until irreversible damage (necrosis) has occurred. * **Option C:** It is **not "never" seen** in open injuries. Even if the skin is broken, the deep fascia may remain intact, or the wound may be too small to decompress the entire compartment. **NEET-PG High-Yield Pearls:** * **The 6 P’s:** Pain (out of proportion), Pallor, Paresthesia, Pulselessness, Paralysis, and Poikilothermia. * **Diagnosis:** Primarily clinical. However, a **Delta pressure** (Diastolic BP minus Compartment pressure) of **≤ 30 mmHg** is diagnostic. * **Most common site:** Deep posterior and anterior compartments of the leg (tibia fractures). * **Treatment:** Emergency **fasciotomy** (leaving the wound open). * **Volkmann’s Ischemic Contracture:** The end-stage result of untreated compartment syndrome in the forearm.

Question 620: What is the target maintenance level for mixed venous oxygen saturation in the management of shock?

A. < 40%
B. 40-50%
C. 50-70% (Correct Answer)
D. >70%

Explanation: ### Explanation **Concept:** Mixed venous oxygen saturation ($SvO_2$) is a global indicator of the balance between systemic oxygen delivery ($DO_2$) and oxygen consumption ($VO_2$). In shock, tissues extract more oxygen due to decreased delivery, leading to a drop in $SvO_2$. Monitoring $SvO_2$ (via a pulmonary artery catheter) or $ScvO_2$ (central venous saturation) helps clinicians assess the adequacy of cardiac output and tissue perfusion. **Why 50-70% is Correct:** The normal range for $SvO_2$ is **65-75%**. In the management of shock, the therapeutic goal is to maintain $SvO_2$ within the **50-70%** range (specifically aiming for $>65\%$ or $ScvO_2 >70\%$). This range indicates that oxygen delivery is sufficient to meet metabolic demands without excessive tissue extraction. **Analysis of Incorrect Options:** * **A (< 40%) & B (40-50%):** These values indicate severe tissue hypoxia and anaerobic metabolism. Low $SvO_2$ suggests either low cardiac output, low hemoglobin, or high metabolic demand (e.g., shivering, fever). Values below 40% are associated with lactic acidosis and impending organ failure. * **D (> 70%):** While normal in healthy individuals, a very high $SvO_2$ in a shocked patient (especially septic shock) can be pathological. It often indicates **cytopathic dysoxia** (tissues cannot utilize oxygen) or **microcirculatory shunting**, where blood bypasses capillary beds. **High-Yield Clinical Pearls for NEET-PG:** * **$ScvO_2$ vs. $SvO_2$:** Central venous oxygen saturation ($ScvO_2$) is usually **2-3% higher** than $SvO_2$ because it does not include desaturated blood from the coronary sinus. * **Early Goal-Directed Therapy (EGDT):** Rivers’ protocol for sepsis traditionally targeted an $ScvO_2 \geq 70\%$. * **Fick’s Principle:** $SvO_2$ is determined by four factors: Hemoglobin, $SaO_2$ (arterial saturation), Cardiac Output, and $VO_2$ (consumption).

Practice by Chapter

Wound Healing and Care

Practice Questions

Surgical Infections

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Fluid and Electrolyte Management

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Nutrition in Surgical Patients

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Hemostasis and Blood Transfusion

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Surgical Instruments and Equipment

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Sutures and Stapling Devices

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Minimal Access Surgery Principles

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Surgical Complications

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Anesthesia Principles for Surgeons

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Surgical Oncology Principles

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Evidence-Based Surgery

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