Surgical Infections — MCQs

Surgical Infections Indian Medical PG Practice Questions and MCQs

Question 141: Percentage of surgical site infection in patients with a clean-contaminated wound after prophylactic antibiotic administration?

A. 1-2%
B. 10-20%
C. <10% (Correct Answer)
D. 20-30%

Explanation: ***<10%*** - For **clean-contaminated wounds**, the rate of surgical site infection (SSI) is generally maintained **below 10%** with proper prophylactic antibiotic administration. - This low percentage reflects the effectiveness of **antibiotic prophylaxis** in preventing SSIs in wounds where controlled entry into a viscus is made. *1-2%* - This range is more typical for **clean wounds** where no viscus is entered, and the risk of contamination is minimal. - Prophylactic antibiotics are highly effective in clean wounds, leading to a very low infection rate. *10-20%* - This percentage is generally considered high for clean-contaminated wounds and may indicate suboptimal antibiotic prophylaxis, an underlying patient risk factor, or a technical surgical issue. - The goal of prophylactic antibiotics is to keep the infection rate well below this range for this wound class. *20-30%* - An infection rate in this range is typically seen in **contaminated** or **dirty wounds**, or in cases where no antibiotics were given. - Such high rates would be unacceptable for a clean-contaminated procedure with appropriate prophylaxis.

Question 142: A 60M diabetic presents with severe ear pain, otorrhea, and facial nerve palsy. CT reveals bony erosion of the temporal bone. His glucose level is 350 mg/dL. Most appropriate management?

A. Oral steroids
B. Intravenous antibiotics and surgical debridement (Correct Answer)
C. Antifungal therapy
D. Topical antibiotics

Explanation: ***Intravenous antibiotics and surgical debridement*** - This presentation suggests **malignant otitis externa**, a severe infection common in **diabetic** or immunocompromised patients, characterized by **severe ear pain**, **otorrhea**, **facial nerve palsy**, and **bony erosion** on CT. - The primary treatment involves high-dose, prolonged **intravenous antipseudomonal antibiotics** (e.g., piperacillin/tazobactam or ceftazidime with ciprofloxacin) and **surgical debridement** to remove necrotic bone and tissue. *Oral steroids* - **Oral steroids** are generally **contraindicated** in active bacterial infections, as they can suppress the immune system and worsen the infection, especially in a diabetic patient. - While steroids might be used later to manage inflammation *after* infection control, they are not the initial or primary treatment for **malignant otitis externa**. *Antifungal therapy* - **Malignant otitis externa** is primarily caused by **_Pseudomonas aeruginosa_**, a bacterium, not a fungus. - While fungal infections can occur in immunocompromised patients, the initial presentation and typical pathogens point to bacterial etiology, rendering antifungal therapy inappropriate as first-line treatment. *Topical antibiotics* - **Topical antibiotics** are insufficient for a severe, invasive infection like **malignant otitis externa** that has caused **bony erosion** and **cranial nerve involvement**. - Systemic, **intravenous antibiotics** are required to achieve adequate tissue penetration and eradicate the deep-seated infection.

Question 143: A laboratory technician is tasked with sterilizing heat-sensitive surgical instruments. Which sterilization method should be chosen and why?

A. Ethylene oxide gas due to its effectiveness at low temperatures (Correct Answer)
B. Autoclaving because it ensures complete sterility
C. Dry heat for its cost-effectiveness
D. UV radiation for its ease of use

Explanation: ***Ethylene oxide gas due to its effectiveness at low temperatures*** - **Ethylene oxide (EtO) gas** is a chemical sterilant effectively used for **heat-sensitive instruments** because it works at **low temperatures** (25-55°C) and can penetrate packaging. - It denatures proteins and DNA, killing all microorganisms, including **spores**, without damaging delicate materials. *Autoclaving because it ensures complete sterility* - **Autoclaving** uses **moist heat under pressure** and is the most effective and common method for sterilizing heat-stable instruments, but it would **damage heat-sensitive items**. - While it ensures complete sterility by denaturing proteins, it is **not suitable for materials that cannot withstand high temperatures**. *Dry heat for its cost-effectiveness* - **Dry heat sterilization** (e.g., in a hot air oven) is suitable for materials that can withstand **high temperatures** (160-180°C) and are sensitive to moisture, such as glassware and powders. - However, it requires **longer exposure times** and **higher temperatures** than EtO, making it unsuitable for heat-sensitive surgical instruments. *UV radiation for its ease of use* - **Ultraviolet (UV) radiation** is primarily used for **surface decontamination** and air purification, effectively killing microorganisms by damaging their DNA. - Its **poor penetration capabilities** mean it cannot sterilize instruments that are packaged or have complex shapes, making it unsuitable for comprehensive sterilization of surgical instruments.

Question 144: What is the most appropriate treatment for a patient with a suspected Brodie's abscess?

A. IV antibiotics only
B. Curettage and drainage (Correct Answer)
C. Amputation
D. Radiotherapy

Explanation: ***Correct: Curettage and drainage*** - **Brodie's abscess** is a subacute or chronic form of osteomyelitis involving a localized collection of pus in the bone - **Surgical intervention** with curettage and drainage is necessary to remove infected tissue and decompress the lesion - This approach directly addresses the localized bone infection, removes necrotic debris, and allows for local antibiotic delivery or culture-guided systemic therapy - Promotes healing and prevents recurrence by eliminating the sequestrum and poorly vascularized tissue *Incorrect: IV antibiotics only* - While antibiotics are crucial for treating osteomyelitis, **IV antibiotics alone** are insufficient for Brodie's abscess - The abscess creates an environment with **poor blood supply** to the central necrotic tissue, limiting antibiotic penetration and efficacy - Surgical debridement is essential to remove the avascular focus and allow antibiotics to work effectively *Incorrect: Amputation* - **Amputation** is an extreme measure reserved for severe, chronic, and uncontrollable osteomyelitis with extensive soft tissue damage or sepsis - Only considered when limb salvage procedures have failed or in cases of life-threatening infection - Not appropriate for a localized Brodie's abscess, which typically responds well to less invasive surgical methods *Incorrect: Radiotherapy* - **Radiotherapy** uses high-energy radiation to treat malignancies - Has **no role** in treating bacterial infections like Brodie's abscess - Would be inappropriate and potentially harmful in this clinical context

Question 145: A 20-year-old patient presents with a fever and a swollen right knee. Joint aspiration reveals purulent fluid. What is the first line of treatment?

A. Immediate surgical drainage and antibiotics (Correct Answer)
B. Observation and follow-up
C. Non-steroidal anti-inflammatory drugs
D. Immobilization and physiotherapy

Explanation: ***Immediate surgical drainage and antibiotics*** - The presence of **purulent joint fluid** in a febrile patient indicates a **septic joint**, which is a medical emergency requiring prompt intervention. - **Surgical drainage** (arthrocentesis or arthroscopy) to remove infected fluid and subsequent **empiric intravenous antibiotics** are crucial to prevent joint destruction and systemic sepsis. *Observation and follow-up* - This approach is inappropriate for a **septic joint** as delaying treatment can lead to rapid **cartilage destruction**, permanent joint damage, and life-threatening sepsis. - **Bacterial infection** in a joint requires urgent antimicrobial therapy and source control, not watchful waiting. *Non-steroidal anti-inflammatory drugs* - **NSAIDs** may help with pain and inflammation but do not address the underlying **bacterial infection** in a septic joint. - Using NSAIDs as a sole treatment would allow the infection to progress unchecked, leading to severe complications. *Immobilization and physiotherapy* - While immobilization might be part of post-treatment care, it is not the **first-line treatment** for an acute septic joint. - **Physiotherapy** is contraindicated in the acute phase of an infection until the infection is controlled, as it can exacerbate inflammation and pain.

Question 146: Which suture material is most appropriate for closing the skin in a contaminated wound to minimize infection risk?

A. Silk
B. Catgut
C. Vicryl
D. Nylon (Correct Answer)

Explanation: ***Nylon*** - **Nylon** is a **monofilament**, non-absorbable suture material, which means it has a smooth surface and does not harbor bacteria as easily as braided sutures. - Its non-absorbable nature ensures long-term wound support while minimizing the risk of a foreign body reaction and subsequent infection in a contaminated field. *Vicryl* - **Vicryl (polyglactin 910)** is a **braided, absorbable suture** that can potentially harbor bacteria within its interstices, making it less suitable for contaminated wounds due to increased infection risk. - Being absorbable, it loses tensile strength over time, which may not be ideal for skin closure where sutures are typically removed after wound healing. *Silk* - **Silk** is a **braided, non-absorbable suture** known for its high tissue reactivity and capillarity, meaning it can absorb fluids and potentially draw bacteria into the wound, increasing infection risk. - Its multifilament nature also makes it more prone to bacterial colonization compared to monofilament sutures. *Catgut* - **Catgut** is a **natural, absorbable suture** derived from animal intestines, which elicits a significant inflammatory response and is rapidly degraded by tissue enzymes. - This rapid absorption and strong inflammatory reaction make it unsuitable for skin closure, especially in contaminated wounds, due to heightened infection potential and unreliable wound support.

Question 147: Which of the following statements is true regarding the spread of infection in tenosynovitis of the finger?

A. In tenosynovitis, the infection of the little finger can spread to the thumb. (Correct Answer)
B. The treatment for tenosynovitis is primarily surgical.
C. Fingers affected by tenosynovitis are typically held in extension to prevent spread of infection.
D. Involvement of the little finger does not lead to infection spreading to the index finger, as they have separate synovial sheaths.

Explanation: ***In tenosynovitis, the infection of the little finger can spread to the thumb.*** - The synovial sheaths of the **little finger (ulnar bursa)** and the **thumb (radial bursa)** communicate in the palm, creating a potential space known as the **space of Parona**. - When infection spreads through both bursae, it creates a **horseshoe abscess**, a characteristic pattern of severe hand infection that wraps around the wrist. - This anatomical communication allows direct spread of infection between the thumb and little finger. *The treatment for tenosynovitis is primarily surgical.* - While this statement has merit, **early pyogenic flexor tenosynovitis** (within 24-48 hours) may respond to **conservative management** with IV antibiotics, splinting, and elevation. - However, **established cases** or those failing conservative treatment require **urgent surgical drainage** to prevent tendon necrosis and permanent functional loss. - Therefore, calling it "primarily" surgical oversimplifies the treatment algorithm, though surgery remains the definitive treatment for most cases. *Fingers affected by tenosynovitis are typically held in extension to prevent spread of infection.* - This is **incorrect**. Affected fingers are held in **flexion**, not extension. - The **flexed posture** is one of **Kanavel's four cardinal signs** of pyogenic flexor tenosynovitis, caused by increased pressure within the tendon sheath. - The other Kanavel signs include fusiform swelling, tenderness along the flexor sheath, and pain with passive extension. *Involvement of the little finger does not lead to infection spreading to the index finger, as they have separate synovial sheaths.* - This is a **true statement** but not the **best answer** regarding spread patterns. - The **index, middle, and ring fingers** have separate synovial sheaths that extend only to the proximal palmar crease and **do not communicate** with each other or with the radial and ulnar bursae. - Infection in the little finger spreads to the thumb (via bursal communication), not to the index finger.

Question 148: Rolled up omentum is seen in cases of?

A. Peritoneal tuberculosis (Correct Answer)
B. Peritoneal metastases
C. Perforation peritonitis
D. Malrotation of gut

Explanation: ***Peritoneal tuberculosis*** - **Rolled up omentum**, along with **ascites** and **peritoneal nodules**, is a classic finding in **peritoneal tuberculosis**. [1] - This is secondary to the inflammatory and fibrotic response of the omentum to the mycobacterial infection. [1] *Peritoneal metastases* - Peritoneal metastases often present with **omental caking**, which is a diffuse thickening and infiltration, rather than a distinct "rolled up" appearance. - The omentum becomes laden with tumor cells, leading to a more irregular and widespread thickening. *Perforation peritonitis* - **Perforation peritonitis** is characterized by diffuse inflammation due to the spillage of visceral contents into the peritoneal cavity, leading to generalized peritonitis. - While the omentum may be inflamed and adherent, it typically does not form a distinct "rolled up" mass but rather tries to wall off the perforation. *Malrotation of gut* - **Malrotation of the gut** is a congenital anomaly involving abnormal positioning of the intestines during embryonic development. - It is associated with conditions like **volvulus** and intestinal obstruction, but not with a "rolled up omentum."

Question 149: Which of the following statements about the management of Pott's paraplegia is incorrect?

A. Chemotherapy is the mainstay of conservative management
B. Decompression via anterolateral approach is most preferred (Correct Answer)
C. Paraplegia not improving with conservative treatment even after 3 - 6 months is an indication for surgical intervention.
D. Posterior fusion and instrumentation can be used to manage the condition.

Explanation: ***Decompression via anterolateral approach is most preferred*** - This statement is **overly absolute** and represents the *incorrect* answer because no single approach is universally "most preferred" for all cases of Pott's paraplegia. - The **choice of surgical approach** depends on the location of pathology, extent of kyphosis, and pattern of cord compression. - **Anterior/anterolateral approach** is actually preferred when there is anterior cord compression from vertebral body destruction and abscess formation (which is common in Pott's disease). - **Posterior approach** is preferred for posterior element involvement, when anterior approach is risky, or for instrumentation and kyphosis correction. - The statement's use of "most preferred" without qualification makes it incorrect, as approach selection must be individualized. *Chemotherapy is the mainstay of conservative management* - **Anti-tubercular therapy (ATT)** is absolutely the cornerstone of treatment for Pott's disease and Pott's paraplegia. - Standard regimen includes 4-drug therapy for 2 months followed by continuation phase, typically for 12-18 months in spinal TB. - Medical management alone can lead to neurological recovery in many cases, especially early-onset paraplegia. *Paraplegia not improving with conservative treatment even after 3-6 months is an indication for surgical intervention* - Persistent or progressive **neurological deficit** despite adequate ATT for 3-6 months is a clear indication for surgical decompression. - This suggests mechanical compression that cannot be resolved by chemotherapy alone. - Other surgical indications include: severe kyphotic deformity, spinal instability, and neurological deterioration during treatment. *Posterior fusion and instrumentation can be used to manage the condition* - **Posterior instrumentation** provides excellent spinal stabilization and is commonly used for: - Correction of kyphotic deformity - Providing stability after anterior decompression - Stand-alone posterior decompression in selected cases - Can be combined with anterior procedures in severe cases requiring circumferential decompression and fusion.

Question 150: Infection of flexor tendon sheath involving the ulnar bursa is diagnosed by?

A. Gower's sign
B. Ludloff's sign
C. Kanavel's sign (Correct Answer)
D. Chvostek's sign

Explanation: ***Kanavel's sign*** - **Kanavel's signs** are a set of four clinical findings highly suggestive of **flexor tenosynovitis**, particularly when involving the ulnar bursa, which forms a continuous sheath with the flexor tendons of the small, ring, and middle fingers. - These signs include **uniform swelling of the digit**, **fixed flexion posture of the digit**, **tenderness along the flexor tendon sheath**, and **pain on passive extension of the digit**. *Chowstek's sign* - **Chvostek's sign** is a clinical finding associated with **hypocalcemia**, characterized by a twitching of the facial muscles in response to tapping over the facial nerve. - It is not related to infections of the hand or flexor tendon sheaths. *Gower's sign* - **Gower's sign** is observed in individuals with **proximal muscle weakness**, particularly in muscular dystrophies. - It describes the characteristic way a patient "climbs up" their legs to stand from a seated position due to weakened hip and thigh muscles. *Ludloff's sign* - **Ludloff's sign** is a diagnostic indicator for an **avulsion fracture of the lesser trochanter** of the femur. - It involves pain felt in the groin and buttock area when the patient attempts to lift an extended leg from a seated position.

Practice by Chapter

Surgical Site Infections

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Intra-abdominal Infections

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Soft Tissue Infections

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Necrotizing Soft Tissue Infections

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Surgical Sepsis

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Tetanus Prophylaxis

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Antimicrobial Prophylaxis

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Antimicrobial Therapy in Surgical Infections

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Surgical Drainage Procedures

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Infection Control in Operating Room

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Biofilms and Implant-Related Infections

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Prevention Strategies

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