General Surgery Principles Practice Questions

Q: Which physical principle does this scalpel operate on?

Ultrasonic waves. ***Ultrasonic waves*** - This **harmonic scalpel** operates using **ultrasonic vibrations** at approximately **55,500 Hz** to simultaneously cut and coagulate tissue. - The ultrasonic energy causes **protein denaturation** through mechanical vibration, providing precise cutting with minimal thermal damage. *Electricity* - **Electrosurgery** uses electrical current to generate heat for cutting and coagulation, not the mechanism shown in this device. - Electrocautery devices have different electrode configurations and produce more **thermal spread** compared to ultrasonic scalpels. *Laser* - **Laser scalpels** use focused **light energy** (photons) to cut tissue through thermal vaporization. - Laser devices require different safety protocols including **eye protection** and have distinct beam delivery systems. *Radiofrequency* - **Radiofrequency devices** use electromagnetic energy in the RF spectrum to generate heat for tissue ablation. - RF energy typically operates at lower frequencies than ultrasonic devices and has different tissue interaction mechanisms.

Q: Homans' sign is seen in which condition?

Deep vein thrombosis. **Explanation:** **Homans' sign** is a classic clinical sign used in the assessment of **Deep Vein Thrombosis (DVT)**. It is elicited by performing passive dorsiflexion of the foot with the knee slightly flexed. A positive sign is indicated by the presence of pain in the calf or popliteal region. The underlying medical concept is that dorsiflexion stretches the gastrocnemius and soleus muscles, which in turn compresses the inflamed deep veins of the calf, triggering pain. **Analysis of Options:** * **Deep Vein Thrombosis (Correct):** As described, the sign specifically targets the calf veins where DVT most commonly originates. * **Pulmonary Embolism:** While PE is a major complication of DVT, Homans' sign is a physical exam finding of the leg, not the lungs. * **Peripheral Vascular Disease (PVD):** PVD (Arterial insufficiency) typically presents with intermittent claudication or rest pain, and signs like Buerger’s test, not Homans' sign. * **Lymphangitis:** This is an inflammation of the lymphatic channels, usually presenting with red streaks and lymphadenopathy, rather than pain on passive dorsiflexion. **Clinical Pearls for NEET-PG:** * **Low Specificity/Sensitivity:** Despite being a common exam question, Homans' sign is clinically unreliable and has low diagnostic accuracy. It is positive in only about 30% of DVT cases and can be positive in other conditions like ruptured Baker’s cyst or calf strain. * **Moses' Sign:** Another DVT sign where pain is elicited by squeezing the calf muscles transversely. * **Lowenberg's Sign:** Pain felt in the calf when a blood pressure cuff is inflated to 80–100 mmHg. * **Gold Standard Investigation:** For DVT, the initial investigation of choice is **Duplex Ultrasonography**, while the gold standard is **Contrast Venography**.

Q: What is the most common site for basal cell carcinoma?

Face. **Explanation:** Basal Cell Carcinoma (BCC) is the most common skin malignancy worldwide. The primary risk factor for its development is chronic, cumulative exposure to **ultraviolet (UV) radiation**. **Why Face is Correct:** Approximately **80% of BCCs occur on the head and neck**, with the **face** being the most frequent site. Specifically, the majority of lesions are found above a line joining the lobe of the ear to the angle of the mouth (the "mask area" of the face). The nose is the single most common anatomical subunit involved. This distribution is directly linked to the face having the highest degree of sun exposure throughout an individual's life. **Why Other Options are Incorrect:** * **Chest and Abdomen:** While BCC can occur on the trunk (often the superficial subtype), these areas are typically protected by clothing, leading to significantly lower incidence compared to the face. * **Extremities:** Although the arms and legs receive sun exposure, they are less frequently involved than the face. BCC is notably rare on the palms and soles, as it arises from hair-bearing skin (pilosebaceous units). **High-Yield Clinical Pearls for NEET-PG:** * **Characteristic Feature:** Classically presents as a pearly, translucent papule with **telangiectasia** and a rolled-out border ("Rodent Ulcer"). * **Metastasis:** BCC is locally invasive but **rarely metastasizes** distant sites. * **Risk Factors:** Fair skin (Fitzpatrick types I & II), Albinism, and Xeroderma Pigmentosum. * **Treatment of Choice:** Surgical excision with clear margins. For high-risk areas on the face, **Mohs Micrographic Surgery** provides the highest cure rate and maximal tissue preservation.

Q: What is the most common organism causing peritonitis?

E. coli. **Explanation:** The most common cause of peritonitis, particularly **secondary peritonitis**, is the translocation of indigenous flora from the gastrointestinal tract following a hollow viscus perforation (e.g., perforated peptic ulcer or appendix). Since the large intestine contains the highest concentration of bacteria, the flora is dominated by Gram-negative aerobes and anaerobes. **Escherichia coli (E. coli)** is the most frequently isolated aerobic organism in these cases, often found in polymicrobial synergy with anaerobes like *Bacteroides fragilis*. **Analysis of Options:** * **B. E. coli (Correct):** It is the leading cause of both secondary peritonitis (due to GI perforation) and Spontaneous Bacterial Peritonitis (SBP) associated with cirrhosis. * **A. Klebsiella:** While a common Gram-negative pathogen in the gut, it is the second most common cause after E. coli. * **C. Staphylococcus aureus:** This is a common cause of peritonitis specifically in patients undergoing **Continuous Ambulatory Peritoneal Dialysis (CAPD)**, where the infection is introduced via the skin/catheter. * **D. Streptococcus:** *Streptococcus pneumoniae* can cause primary peritonitis in children (especially those with nephrotic syndrome), but it is not the most common cause in the general population. **Clinical Pearls for NEET-PG:** * **Most common cause of SBP:** E. coli. * **Most common cause of CAPD peritonitis:** *Staphylococcus epidermidis* (overall) or *Staphylococcus aureus*. * **Most common cause of Post-operative peritonitis:** Often involves multi-drug resistant organisms like *Pseudomonas* or *Enterococcus*. * **Primary Peritonitis (Childhood):** Often associated with *Streptococcus pneumoniae* or Group A *Streptococcus*.

Q: Which of the following are not non-absorbable sutures?

Catgut. ### Explanation The classification of suture materials into **absorbable** and **non-absorbable** is a fundamental concept in surgery. Absorbable sutures are those that lose their tensile strength within 60 days and are eventually digested by enzymatic action or hydrolysis. **Why Catgut is the Correct Answer:** **Catgut** is a natural, **absorbable** suture derived from the submucosa of sheep intestine or the serosa of bovine intestine. It is degraded by proteolytic enzymes. Plain catgut loses its tensile strength rapidly (7–10 days), while Chromic catgut, treated with chromium salts to delay absorption, maintains strength for 14–21 days. Because it is absorbable, it is the "odd one out" among the non-absorbable options provided. **Analysis of Incorrect Options:** * **A. Silk:** A natural, non-absorbable suture produced by silkworm larvae. Although it may degrade very slowly over years, it is classified clinically as non-absorbable. * **C. Metal (Stainless Steel):** A synthetic, non-absorbable material. It provides the highest tensile strength and is used for bone repair or sternal closure. * **D. Nylon (Polyamide):** A synthetic, non-absorbable monofilament. It is commonly used for skin closure due to its high tensile strength and low tissue reactivity. **NEET-PG High-Yield Pearls:** * **Fastest absorption:** Catgut is absorbed faster than synthetic absorbables like Polyglycolic acid (Dexon) or Polyglactin (Vicryl). * **Hydrolysis vs. Proteolysis:** Synthetic absorbables (Vicryl, PDS) are broken down by **hydrolysis** (less reactive), whereas natural absorbables (Catgut) are broken down by **enzymatic proteolysis** (more reactive). * **Propropylene (Prolene):** The non-absorbable suture of choice for vascular anastomoses because it is the least thrombogenic. * **Black Silk:** Known for having the highest tissue reactivity among non-absorbable sutures.

Q: All of the following conditions are associated with an increased risk of breast cancer, except?

Hereditary nonpolyposis colorectal cancer (HNPCC). **Explanation:** The correct answer is **D. Hereditary nonpolyposis colorectal cancer (HNPCC)**, also known as **Lynch Syndrome**. **1. Why HNPCC is the correct answer:** Lynch Syndrome is caused by germline mutations in DNA mismatch repair (MMR) genes (*MLH1, MSH2, MSH6, PMS2*). While it significantly increases the risk of **colorectal, endometrial, ovarian, gastric, and urinary tract cancers**, it is **not** classically associated with an increased risk of breast cancer. In the context of NEET-PG, breast cancer is not considered part of the Lynch syndrome tumor spectrum. **2. Analysis of incorrect options:** * **Peutz-Jeghers Syndrome (PJS):** Caused by *STK11* mutations. It is characterized by hamartomatous polyps and mucocutaneous pigmentation. Patients have a significantly elevated lifetime risk of breast cancer (approx. 30-50%). * **Cowden Syndrome:** Part of the PTEN Hamartoma Tumor Syndrome. Mutations in the *PTEN* gene lead to multiple hamartomas and a very high lifetime risk of breast cancer (up to 85%). * **BRCA 1 Mutation:** This is the most well-known genetic risk factor for breast cancer. BRCA1 mutations carry a lifetime breast cancer risk of 60-80% and are also associated with ovarian and pancreatic cancers. **Clinical Pearls for NEET-PG:** * **Li-Fraumeni Syndrome (*TP53*):** Another high-yield association with early-onset breast cancer, sarcomas, and adrenocortical carcinomas. * **Lynch Syndrome Mnemonic:** Remember **"CEO"** (Colorectal, Endometrial, Ovarian) for the primary associated malignancies. * **Ataxia-Telangiectasia:** Carriers of the *ATM* gene mutation also have an increased risk of breast cancer.

Question 1

Which physical principle does this scalpel operate on?

Accepted Answer

Ultrasonic waves

Answer

Electricity

Answer

Laser

Answer

Radiofrequency

Question 2

Homans' sign is seen in which condition?

Accepted Answer

Deep vein thrombosis

Answer

Pulmonary embolism

Answer

Peripheral vascular disease

Answer

Lymphangitis

Question 3

Which of the following is NOT a natural response to injury?

Accepted Answer

Anabolism

Answer

Immobility/rest

Answer

Anorexia

Answer

Catabolism

Question 4

What is the most common site for basal cell carcinoma?

Accepted Answer

Face

Answer

Chest

Answer

Abdomen

Answer

Extremities

Question 5

What are the differentiating features between sepsis and trauma?

Accepted Answer

Energy requirement

Answer

Catabolism

Answer

Insulin resistance

Answer

Fluid loss

Question 6

What is the most common organism causing peritonitis?

Accepted Answer

E. coli

Answer

Klebsiella

Answer

Staphylococcus aureus

Answer

Streptococcus

Question 7

Which of the following are not non-absorbable sutures?

Accepted Answer

Catgut

Answer

Silk

Answer

Metal

Answer

Nylon

Question 8

All of the following conditions are associated with an increased risk of breast cancer, except?

Accepted Answer

Hereditary nonpolyposis colorectal cancer (HNPCC)

Answer

Peutz-Jeghers syndrome

Answer

Cowden syndrome

Answer

BRCA 1 mutation

Question 9

What is the most important principle during tooth extraction?

Accepted Answer

Least trauma to both bone and mucosa while extracting the tooth in pieces.

Answer

Least trauma to bone while extracting the whole tooth.

Answer

Least trauma to mucosa while extracting the whole tooth.

Answer

None of the above.

Question 10

In infection involving the submandibular space when extraoral incision and drainage are necessary, which of the following structures must be divided?

Accepted Answer

Skin, superficial fascia, platysma, masseter muscle, and deep cervical fascia

Answer

Skin only

Answer

Skin and superficial fascia only

Answer

Skin, superficial fascia, platysma, and masseter muscle

General Surgery Principles — MCQs

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