General Surgery Principles — MCQs

General Surgery Principles Indian Medical PG Practice Questions and MCQs

Question 31: Which of the following statements about surgical wounds is incorrect?

A. No antibiotics are required in clean surgery.
B. Incision of an abscess is considered a contaminated wound. (Correct Answer)
C. Spillage of stomach contents converts a clean-contaminated case to a contaminated case.
D. In clean-contaminated wounds, the infection rate is less than 10%.

Explanation: ### Explanation The classification of surgical wounds is a high-yield topic based on the **CDC Surgical Wound Classification**, which predicts the risk of postoperative surgical site infection (SSI). #### Why Option B is Incorrect (The Correct Answer) Incision and drainage of an abscess is classified as a **Dirty (Class IV)** wound, not a contaminated wound. Dirty wounds involve clinical infection, perforated viscera, or old traumatic wounds with retained devitalized tissue. Since an abscess contains active pus and established infection, it falls into this highest risk category. #### Analysis of Other Options * **Option A:** In **Clean (Class I)** surgeries (e.g., hernia repair, thyroidectomy), the respiratory, alimentary, or genitourinary tracts are not entered. Prophylactic antibiotics are generally not required unless a prosthetic implant is used. * **Option C:** A **Clean-Contaminated (Class II)** wound involves controlled entry into a hollow viscus. However, if there is a major break in technique or **gross spillage** of contents (like stomach or biliary contents), it is upgraded to a **Contaminated (Class III)** wound. * **Option D:** The expected infection rate for Clean-Contaminated wounds, when proper technique and prophylaxis are used, is typically **between 3% and 10%**. #### NEET-PG High-Yield Pearls * **Clean (Class I):** No inflammation; no tracts entered. SSI risk: <2%. * **Clean-Contaminated (Class II):** Controlled entry into tracts (e.g., elective cholecystectomy, appendectomy). SSI risk: 3–10%. * **Contaminated (Class III):** Accidental wounds, gross spillage, or acute non-purulent inflammation. SSI risk: 10–20%. * **Dirty (Class IV):** Pus present, perforated viscera (e.g., perforated diverticulitis). SSI risk: 20–40%.

Question 32: Which one of the following organisms is not associated with synergistic gangrene?

A. Escherichia (Correct Answer)
B. Staphylococcus
C. Clostridium
D. Streptococcus

Explanation: ### Explanation **Synergistic Gangrene** (specifically Meleney’s synergistic gangrene) is a progressive, polymicrobial infection of the skin and subcutaneous tissues. The core pathophysiology relies on the **synergy** between different bacterial species, where the presence of one enhances the virulence of another. **1. Why Escherichia is the Correct Answer:** While *Escherichia coli* is a common cause of many surgical infections (like peritonitis or Fournié’s gangrene), it is **not** a primary component of the classic "Meleney’s Synergistic Gangrene." Meleney’s gangrene is traditionally defined by the symbiosis between a microaerophilic non-hemolytic Streptococcus and an aerobic Staphylococcus. **2. Analysis of Other Options:** * **Staphylococcus (Option B):** This is a classic component. In Meleney’s gangrene, *Staphylococcus aureus* acts as the aerobic partner that consumes oxygen, creating an anaerobic environment for the co-infecting streptococci. * **Clostridium (Option C):** While *Clostridium* is the hallmark of Gas Gangrene (Clostridial myonecrosis), it is also frequently involved in various forms of synergistic necrotizing fasciitis and polymicrobial gangrene. * **Streptococcus (Option D):** Microaerophilic or anaerobic *Streptococci* are the essential "drivers" of synergistic gangrene. They thrive in the low-oxygen environment created by aerobic bacteria. **Clinical Pearls for NEET-PG:** * **Meleney’s Gangrene:** Typically follows abdominal or thoracic surgery around the site of a drain or wound. It presents with a central area of gangrene surrounded by a zone of purple/dusky skin and an outer zone of erythema. * **Fournier’s Gangrene:** A specific type of synergistic gangrene affecting the scrotum and perineum, often involving a mix of aerobes (*E. coli*, *Klebsiella*) and anaerobes (*Bacteroides*). * **Key Distinction:** Unlike Gas Gangrene (Clostridial), synergistic gangrene primarily involves the skin and fascia, often sparing the underlying muscle initially.

Question 33: Which instrument is primarily utilized for the principle of bone dilatation in exodontia?

A. Forceps (Correct Answer)
B. Elevator
C. Any of the above
D. None

Explanation: ### Explanation In exodontia, the extraction of a tooth relies on mechanical principles to expand the bony socket and sever the periodontal ligament. **1. Why Forceps is the Correct Answer:** The primary mechanism of **dental forceps** is **bone dilatation**. When a clinician applies forceps to a tooth, they use controlled lateral (bucco-lingual) and rotational forces. These forces are transmitted through the tooth root to the alveolar bone. Because the bone is somewhat elastic, these repetitive movements cause the socket to expand (dilate) and the cortical plates to thin or bend, eventually allowing the widest part of the root to pass through the socket opening. **2. Why Other Options are Incorrect:** * **Elevator:** While elevators are used to luxate teeth, their primary mechanical principles are the **Lever principle** (Class I), the **Wedge principle**, and the **Wheel and Axle principle**. They are used to displace the tooth within the socket or sever ligaments, but they do not primarily aim to dilate the entire bony housing in the same manner as forceps. * **Any of the above:** Incorrect because the specific principle of "bone dilatation" is classically attributed to the mechanical action of forceps. **Clinical Pearls for NEET-PG:** * **Mechanical Principles of Elevators:** Remember the "Big Three"—Lever (most common), Wedge (used to split roots), and Wheel and Axle (e.g., Winter’s cryer). * **Forceps Movement:** In the mandible, labial/buccal bone is thinner (except at the molars), so dilatation is easier toward the buccal aspect. In the maxilla, the labial plate is generally thinner. * **Expansion vs. Fracture:** Controlled dilatation is the goal; excessive force without proper expansion leads to alveolar bone fracture.

Question 34: Which of the following is a cyst without a lining?

A. Radicular cyst
B. Dentigerous cyst
C. Nasopalatine duct cyst
D. Hemorrhagic / Traumatic bone cyst (Correct Answer)

Explanation: ### Explanation **Correct Answer: D. Hemorrhagic / Traumatic bone cyst** **Underlying Medical Concept:** In pathology, cysts are classified into **True Cysts** (lined by epithelium) and **Pseudocysts** (lacking an epithelial lining). The Hemorrhagic or Traumatic Bone Cyst (TBC) is a classic example of a **pseudocyst**. It is an empty or fluid-filled cavity within the bone that lacks a demonstrable epithelial lining. Pathogenesis is often attributed to the "Traumatic-Hemorrhage Theory," where an intramedullary clot fails to organize and instead undergoes liquefaction, leaving an empty void. **Analysis of Incorrect Options:** * **A. Radicular Cyst:** This is the most common inflammatory odontogenic cyst. It is a **true cyst** lined by non-keratinized stratified squamous epithelium, usually arising from the Rest Cells of Malassez. * **B. Dentigerous Cyst:** A developmental odontogenic cyst that surrounds the crown of an unerupted tooth. It is a **true cyst** lined by reduced enamel epithelium. * **C. Nasopalatine Duct Cyst:** The most common non-odontogenic cyst of the maxilla. It is a **true cyst** lined by a variety of epithelia (squamous, cuboidal, or respiratory/ciliated columnar). **Clinical Pearls for NEET-PG:** * **Radiographic Appearance:** TBC typically presents as a well-defined radiolucency that **scallops** between the roots of teeth without causing root resorption or tooth displacement. * **Common Site:** Most frequently found in the **mandible** (symphysis or body) of young patients (10–20 years). * **Surgical Finding:** Upon surgical exploration, the cavity is often found to be **empty** (containing only air) or containing a small amount of serosanguinous fluid. * **Other Pseudocysts to Remember:** Aneurysmal Bone Cyst (ABC) and Stafne’s Bone Cavity are also pseudocysts (no epithelial lining).

Question 35: What is the formula for the modified shock index?

A. Heart rate / Systolic blood pressure
B. Heart rate / Diastolic blood pressure
C. Heart rate / Mean arterial pressure (Correct Answer)
D. Pulse rate / Systolic blood pressure

Explanation: **Explanation:** The **Modified Shock Index (MSI)** is a clinical tool used to assess hemodynamic stability and predict mortality or the need for massive transfusion in trauma and emergency settings. **1. Why Option C is Correct:** The formula for the Modified Shock Index is **Heart Rate (HR) / Mean Arterial Pressure (MAP)**. While the traditional Shock Index (SI) uses only systolic pressure, the MSI incorporates the MAP because it accounts for both systolic and diastolic components. Since MAP represents the actual perfusion pressure seen by organs, the MSI is a more sensitive predictor of clinical outcomes and occult shock than heart rate or blood pressure alone. A normal MSI range is typically **0.7 to 1.3**. **2. Why Other Options are Incorrect:** * **Option A:** This is the formula for the **Traditional Shock Index (SI)**. While useful, it can sometimes miss patients in "compensated shock." * **Option B:** Heart rate divided by diastolic blood pressure is not a standard clinical index used in trauma protocols. * **Option D:** Pulse rate/SBP is essentially the same as Option A (as HR and Pulse are usually interchangeable in this context) and represents the standard SI, not the modified version. **3. High-Yield Clinical Pearls for NEET-PG:** * **Normal Shock Index (SI):** 0.5 – 0.7. An SI > 0.9 is associated with increased mortality. * **MSI Utility:** An MSI **> 1.3** is a strong predictor of poor prognosis and indicates a high risk of requiring emergency intervention. * **Age-Specific:** In pediatrics, the **Paediatric Adjusted Shock Index (SIPA)** is used, as baseline heart rates are higher in children. * **Clinical Significance:** MSI is superior to the standard SI in predicting "occult shock"—where a patient has normal vital signs but is actually hypoperfusing at a cellular level.

Question 36: Which of the following is a non-absorbable suture?

A. Polypropylene (Correct Answer)
B. Polyglycolic acid
C. Collagen
D. All

Explanation: **Explanation:** The classification of suture materials into **absorbable** and **non-absorbable** is a fundamental concept in surgery, determined by whether the body’s tissues can degrade and digest the material over time. **1. Why Polypropylene is Correct:** **Polypropylene (Prolene)** is a synthetic, monofilament, **non-absorbable** suture. It is biologically inert and maintains its tensile strength indefinitely because it is not degraded by host enzymes or hydrolysis. It is the material of choice for vascular anastomoses, abdominal wall closure (linea alba), and subcuticular skin closure due to its high tensile strength and low tissue reactivity. **2. Why the other options are incorrect:** * **Polyglycolic acid (Dexon):** This is a synthetic, braided, **absorbable** suture. It is degraded via **hydrolysis** and typically loses its tensile strength within 3–4 weeks. * **Collagen:** This is a natural **absorbable** suture derived from the submucosa of sheep intestine or serosa of cattle. It is degraded by **proteolytic enzymatic digestion**. "Catgut" is the most common example of a collagen-based suture. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism of Degradation:** Natural sutures (Silk, Catgut) are degraded by **proteolysis**, whereas synthetic sutures (Vicryl, PDS, Dexon) are degraded by **hydrolysis**. * **Suture of Choice:** * **Vascular surgery:** Polypropylene (due to its plasticity and low friction). * **Biliary/Urinary tract:** Absorbable sutures (to prevent them from acting as a nidus for stone formation). * **Infected wounds:** Monofilament (like Nylon or Prolene) is preferred over braided (like Silk or Vicryl) to prevent bacterial "wicking." * **Steel:** The strongest non-absorbable suture, often used for sternal closure.

Question 37: Splenectomy is contraindicated in which of the following hemolytic anemias?

A. Stomatocytosis (Correct Answer)
B. Elliptocytosis
C. Sickle cell disease
D. All of the above

Explanation: **Explanation:** **1. Why Stomatocytosis is the Correct Answer:** Hereditary Stomatocytosis (specifically the overhydrated subtype) is a rare hemolytic anemia where the red cell membrane is abnormally permeable to cations. Splenectomy is **contraindicated** in these patients because it is associated with a life-threatening risk of **severe thromboembolic complications** (such as portal vein thrombosis and pulmonary hypertension). Unlike other hemolytic anemias, the clinical benefit of splenectomy in stomatocytosis is minimal compared to the high risk of fatal clotting events. **2. Why the Other Options are Incorrect:** * **Hereditary Elliptocytosis (Option B):** Splenectomy is the treatment of choice for patients with symptomatic, severe hemolysis or significant anemia. It effectively increases the lifespan of the elliptical red cells. * **Sickle Cell Disease (Option C):** While patients often undergo "autosplenectomy" due to repeated infarcts, surgical splenectomy is indicated in specific cases such as **acute splenic sequestration crisis** or hypersplenism. It is not contraindicated; rather, it can be life-saving in these acute scenarios. **Clinical Pearls for NEET-PG:** * **Hereditary Spherocytosis:** Splenectomy is the **gold standard** treatment (usually performed after age 5-6 to reduce sepsis risk). * **Post-Splenectomy Sepsis (OPSI):** Most commonly caused by *Streptococcus pneumoniae*. Vaccination against encapsulated organisms (Pneumococcus, Meningococcus, H. influenzae) should be given 2 weeks before elective surgery. * **Peripheral Smear Finding:** Look for **Howell-Jolly bodies** post-splenectomy, which indicate absent splenic filtration. * **Absolute Contraindication:** Splenectomy should never be performed in asymptomatic patients or those with mild compensation where the risks of surgery outweigh the benefits.

Question 38: Which of the following is NOT true about hydatid cysts?

A. The most common site is the liver.
B. Calcification is common in the lung. (Correct Answer)
C. The kidney may be involved.
D. Liver cysts are more common in the right lobe.

Explanation: Hydatid disease, caused by the larval stage of *Echinococcus granulosus*, is a high-yield topic for NEET-PG. Here is the breakdown of the options: **Why Option B is the correct answer (False Statement):** Calcification is a sign of senescence or death of the parasite. While it is very common in **liver** hydatid cysts (occurring in 20–30% of cases), it is **extremely rare in the lung**. This is because the lung parenchyma is highly elastic and offers little resistance, allowing the cyst to expand rapidly rather than undergo the chronic pressure changes that lead to calcification. **Analysis of Incorrect Options (True Statements):** * **Option A:** The **liver** is indeed the most common site (approx. 70%), as it acts as the first capillary filter for the portal venous drainage from the intestine. * **Option C:** The **kidney** can be involved (approx. 2–3%), usually via systemic circulation. It often presents with "hydatiduria" if the cyst ruptures into the collecting system. * **Option D:** Cysts are more common in the **right lobe** of the liver because it receives the bulk of the portal blood flow compared to the left lobe. **Clinical Pearls for NEET-PG:** * **Pathognomonic Sign:** "Water lily sign" (Camelot sign) on imaging indicates a ruptured endocyst. * **Serology:** ELISA is the screening test of choice. * **Treatment:** PAIR (Puncture, Aspiration, Injection, Re-aspiration) is used for liver cysts, but **never for lung cysts** due to the risk of anaphylaxis and bronchial fistula. * **Drug of Choice:** Albendazole (given pre- and post-operatively to reduce recurrence).

Question 39: In an adult patient with pleural effusion, what is the most appropriate site for thoracentesis?

A. 5th intercostal space in the midclavicular line
B. 7th intercostal space in the midaxillary line (Correct Answer)
C. 2nd intercostal space adjacent to the sternum
D. 10th intercostal space adjacent to the vertebral column

Explanation: ### Explanation **Correct Answer: B. 7th intercostal space in the midaxillary line** Thoracentesis (pleural tap) is performed to remove fluid from the pleural space. The goal is to select a site that is low enough to access gravity-dependent fluid but high enough to avoid injury to the diaphragm and abdominal viscera (liver/spleen). The **7th to 9th intercostal spaces** between the **midaxillary line and the posterior axillary line** are the preferred sites. At the midaxillary line, the 7th intercostal space provides a safe window above the diaphragmatic reflection while ensuring the needle enters the widest part of the costodiaphragmatic recess. **Analysis of Incorrect Options:** * **Option A (5th ICS, Midclavicular line):** This site is too high for efficient fluid drainage and carries a risk of injuring the heart (on the left) or the lung parenchyma. * **Option C (2nd ICS, Midclavicular line):** This is the classic site for **needle decompression of a tension pneumothorax**, not for pleural effusion. * **Option D (10th ICS):** This is too low. The diaphragm typically rises to the level of the 8th–10th ribs posteriorly during expiration; inserting a needle here poses a high risk of penetrating the diaphragm and causing intra-abdominal injury (liver or spleen laceration). **NEET-PG High-Yield Pearls:** * **The "Safe Zone":** Always insert the needle **immediately above the rib (superior border)** to avoid the neurovascular bundle (Intercostal vein, artery, and nerve), which runs in the costal groove at the inferior border of the rib. * **Positioning:** The patient should ideally be sitting upright, leaning forward. * **Fluid Limit:** To avoid re-expansion pulmonary edema, do not remove more than **1,000–1,500 mL** of fluid in a single session. * **Gold Standard:** Ultrasound-guided thoracentesis is now preferred over the "blind" clinical approach to minimize complications like pneumothorax.

Question 40: Patients undergoing splenectomy require which of the following vaccinations?

A. Pneumococcus
B. Gonococcus
C. Haemophilus
D. Influenza (Correct Answer)

Explanation: **Explanation:** The spleen is a critical lymphoid organ responsible for filtering encapsulated bacteria and producing opsonizing antibodies (Tuftsin and Properdin). Post-splenectomy, patients are at a lifelong risk of **Overwhelming Post-Splenectomy Infection (OPSI)**, which carries a high mortality rate. **Why Influenza is the Correct Answer:** While the primary threat comes from encapsulated bacteria, **Influenza** vaccination is mandatory and administered **annually**. The rationale is twofold: influenza infection can lead to secondary bacterial pneumonia (often by *S. pneumoniae*), and viral infections can further suppress the immune system in an already vulnerable asplenic patient. According to current guidelines (CDC/ACIP), annual influenza vaccination is a standard component of post-splenectomy care. **Analysis of Incorrect Options:** * **A. Pneumococcus:** This is a trick of phrasing. While *Streptococcus pneumoniae* is the **most common** cause of OPSI, the question asks which vaccination is required. If this were a "multiple correct" or "most important" scenario, Pneumococcus would be a primary choice. However, in the context of this specific question's structure, Influenza is highlighted as the routine annual requirement. * **B. Gonococcus:** *Neisseria gonorrhoeae* is not an encapsulated organism typically associated with OPSI. There is no clinical indication for Gonococcal vaccination post-splenectomy. * **C. Haemophilus:** *Haemophilus influenzae* type b (Hib) is a major cause of OPSI, but like Pneumococcus, it is usually given as a one-time or booster dose, not the annual requirement often tested in this format. **NEET-PG High-Yield Pearls:** 1. **The "Big Three":** Post-splenectomy patients must be vaccinated against *S. pneumoniae*, *H. influenzae* type b, and *N. meningitidis*. 2. **Timing:** For elective surgery, vaccinate **2 weeks before**. For emergency surgery, vaccinate **2 weeks after** (to allow the immune system to recover from surgical stress). 3. **Prophylaxis:** Children post-splenectomy often require daily oral Penicillin prophylaxis until age 5 or for at least 5 years post-op. 4. **Most common organism in OPSI:** *Streptococcus pneumoniae* (50-90% of cases).

Practice by Chapter

Wound Healing and Care

Practice Questions

Surgical Infections

Practice Questions

Fluid and Electrolyte Management

Practice Questions

Nutrition in Surgical Patients

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Hemostasis and Blood Transfusion

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Surgical Instruments and Equipment

Practice Questions

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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