Surgical Infections Practice Questions

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

<10%. ***<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.

Q: 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?

Intravenous antibiotics and surgical debridement. ***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.

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

Ethylene oxide gas due to its effectiveness at low temperatures. ***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.

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

Curettage and drainage. ***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

Q: 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?

Immediate surgical drainage and antibiotics. ***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.

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

Nylon. ***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.

Q: Rolled up omentum is seen in cases of?

Peritoneal tuberculosis. ***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."

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

Kanavel's sign. ***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.

Question 1

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

Accepted Answer

<10%

Answer

1-2%

Answer

10-20%

Answer

20-30%

Question 2

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?

Accepted Answer

Intravenous antibiotics and surgical debridement

Answer

Oral steroids

Answer

Antifungal therapy

Answer

Topical antibiotics

Question 3

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

Accepted Answer

Ethylene oxide gas due to its effectiveness at low temperatures

Answer

Autoclaving because it ensures complete sterility

Answer

Dry heat for its cost-effectiveness

Answer

UV radiation for its ease of use

Question 4

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

Accepted Answer

Curettage and drainage

Answer

IV antibiotics only

Answer

Amputation

Answer

Radiotherapy

Question 5

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?

Accepted Answer

Immediate surgical drainage and antibiotics

Answer

Observation and follow-up

Answer

Non-steroidal anti-inflammatory drugs

Answer

Immobilization and physiotherapy

Question 6

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

Accepted Answer

Nylon

Answer

Silk

Answer

Catgut

Answer

Vicryl

Question 7

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

Accepted Answer

In tenosynovitis, the infection of the little finger can spread to the thumb.

Answer

The treatment for tenosynovitis is primarily surgical.

Answer

Fingers affected by tenosynovitis are typically held in extension to prevent spread of infection.

Answer

Involvement of the little finger does not lead to infection spreading to the index finger, as they have separate synovial sheaths.

Question 8

Rolled up omentum is seen in cases of?

Accepted Answer

Peritoneal tuberculosis

Answer

Peritoneal metastases

Answer

Perforation peritonitis

Answer

Malrotation of gut

Question 9

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

Accepted Answer

Decompression via anterolateral approach is most preferred

Answer

Chemotherapy is the mainstay of conservative management

Answer

Paraplegia not improving with conservative treatment even after 3 - 6 months is an indication for surgical intervention.

Answer

Posterior fusion and instrumentation can be used to manage the condition.

Question 10

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

Accepted Answer

Kanavel's sign

Answer

Gower's sign

Answer

Ludloff's sign

Answer

Chvostek's sign

Surgical Infections — MCQs

Surgical Infections — MCQs

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