General Surgery Principles Practice Questions

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

Reduce serum osmolality and cause brain edema. **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.

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

Very old people. **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.

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

Erythema limited to the area of oedema. **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.

Q: What is a Verres needle used for?

Creating pneumoperitoneum. 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**.

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

Umbilical hernia. ### **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.

Q: What is true about compartment syndrome?

Pain on passive movement. **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.

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

50-70%. ### 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 ( 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).

Question 1

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

Accepted Answer

Reduce serum osmolality and cause brain edema

Answer

Improve cerebral perfusion

Answer

Provide glucose substrate for cerebral metabolism

Answer

Reduce intracranial pressure and cause cerebral edema

Question 2

What is the primary method for preventing surgical wound infection?

Accepted Answer

Preoperative antibiotic therapy

Answer

Preoperative shaving

Answer

Monofilament sutures

Answer

Wound apposition

Question 3

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

Accepted Answer

Very old people

Answer

Infants

Answer

Children

Answer

Adults

Question 4

Which of the following is NOT a feature of necrotising fasciitis?

Accepted Answer

Erythema limited to the area of oedema

Answer

Disproportionate pain

Answer

Dishwater pus

Answer

Crepitus

Question 5

What is a Verres needle used for?

Accepted Answer

Creating pneumoperitoneum

Answer

Liver biopsy

Answer

Bone marrow biopsy

Answer

Spinal anesthesia

Question 6

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?

Accepted Answer

Intravenous fluid resuscitation only.

Answer

Intravenous fluid resuscitation combined with dopamine infusion.

Answer

Dopamine infusion only.

Answer

High-dose antibiotics.

Question 7

In which condition does the jaw deviate to the same side?

Accepted Answer

All of the above

Answer

TMJ ankylosis

Answer

Hypoplasia of condyle

Answer

Subcondylar fractures

Question 8

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

Accepted Answer

Umbilical hernia

Answer

Omphalitis

Answer

Omphalocele

Answer

Gastroschisis

Question 9

What is true about compartment syndrome?

Accepted Answer

Pain on passive movement

Answer

Common in open lower limb fractures

Answer

Absence of pulses is an early sign

Answer

Never seen in open injuries

Question 10

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

Accepted Answer

50-70%

Answer

< 40%

Answer

40-50%

Answer

>70%

General Surgery Principles — MCQs

General Surgery Principles — MCQs

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