Surgical Infections Practice Questions

Q: Which of the following is an example of a clean surgery?

Hernia surgery. ***Hernia surgery*** - **Clean surgeries** involve no entry into hollow viscera (e.g., gastrointestinal, genitourinary, or respiratory tract) and are characterized by **no inflammation** or infection. Hernia repair typically fits this description. - The risk of **surgical site infection** (SSI) is usually less than 2% in clean cases, making it a benchmark for surgical infection control. *Gastric surgery* - This involves entry into the **gastrointestinal tract**, which is considered a **contaminated** or **clean-contaminated** procedure due to the presence of bacteria. - The risk of infection is higher than in clean surgeries, often requiring prophylactic antibiotics. *Cholecystectomy* - This procedure involves the **gallbladder**, which is part of the biliary system, often considered a **clean-contaminated** wound if bile spills or if there's no evidence of active infection. - If performed for **acute cholecystitis** (inflammation/infection), it would be classified as **contaminated** or **dirty**. *Rectal surgery* - This involves the **rectum**, which is part of the lower **gastrointestinal tract** and contains a high bacterial load. - Procedures involving the rectum are classified as **contaminated** or **dirty** due to the high risk of bacterial contamination.

Q: Most common organism causing infection after an open fracture?

Staphylococcus aureus. ***Staphylococcus aureus*** - *Staphylococcus aureus* is the **most common organism** causing infection in **open fractures**, accounting for 30-40% of cases. - It is present on **skin flora** and readily contaminates traumatic wounds, making it the predominant pathogen in the immediate post-injury period. - **Antibiotic prophylaxis** for open fractures (cephalosporins) primarily targets *S. aureus*, reflecting its clinical importance. - It causes both **early and late infections** in open fractures and is the leading cause of **post-traumatic osteomyelitis**. *Pseudomonas* - *Pseudomonas aeruginosa* can cause infections in open fractures but is **not the most common** organism. - More frequently seen in **Type III open fractures** with extensive soft tissue damage, **nosocomial infections**, or **delayed infections** after hospitalization. - Associated with **contaminated water exposure** and **chronic wounds** rather than being the primary pathogen in acute open fractures. *Klebsiella* - *Klebsiella* species are typically associated with **nosocomial infections**, particularly **urinary tract infections** and **pneumonia**. - Rarely the primary pathogen in acute open fracture infections. - May be seen in **hospital-acquired** infections in patients with prolonged hospitalization. *Gonococcus* - **Gonococcus** (*Neisseria gonorrhoeae*) is primarily associated with **sexually transmitted infections** and can cause **septic arthritis** through hematogenous spread. - It does **not** cause infections in open fractures as it is not found in the environment or on skin. - The mode of transmission is completely unrelated to trauma or wound contamination.

Q: What is the most common complication of a felon?

Osteomyelitis. ***Osteomyelitis*** - A **felon** is a severe infection of the **distal pulp space** of the fingertip, which has numerous fibrous septa. - The tightly compartmentalized nature of this space can lead to increased pressure, compromising blood supply and facilitating the spread of infection to the underlying **phalanx bone**, causing **osteomyelitis**. *Subungual hematoma* - A **subungual hematoma** is a collection of blood under the nail, usually resulting from direct trauma. - It is not a complication of an infection like a felon, but rather a separate traumatic injury. *Infective arthritis* - **Infective arthritis** involves the joint space, typically resulting from direct inoculation, hematogenous spread, or spread from adjacent soft tissue infection. - While possible, it is less common for a felon to directly spread to the **distal interphalangeal joint** compared to the more immediate risk of bone involvement. *No complications* - A **felon** is a serious infection that, if left untreated, almost always leads to complications due to the unique anatomy of the fingertip pulp space. - The high pressure within the compartments of the distal pulp makes it prone to necrosis and spread of infection to adjacent structures.

Q: What is a felon or whitlow?

Terminal pulp space infection. ***Terminal pulp space infection*** - A **felon**, also known as a **whitlow**, is a **closed-space infection** of the **digital pulp** of the fingertip, distal to the distal interphalangeal joint. - This area contains numerous fibrous septa that create multiple small compartments, which, when infected, can lead to increased pressure, severe pain, and potential **ischemic necrosis** of the bone. *Infection of the ulnar bursa* - An infection of the **ulnar bursa** involves the synovial sheath surrounding the flexor tendons of the medial three and a half digits, extending into the palm. - This condition is often referred to as **ulnar bursitis** or **tenosynovitis** and presents with distinct clinical signs, such as swelling in the palm and along the little finger, known as Kanavel's signs. *Infection of the radial bursa* - An infection of the **radial bursa** affects the synovial sheath around the flexor pollicis longus tendon of the thumb. - This condition is known as **radial bursitis** or **thenar space infection** and typically presents with swelling and tenderness confined to the thumb and thenar eminence. *Midpalmar space infection* - A **midpalmar space infection** occurs in the deep fascial space of the palm, located between the flexor tendons and the interosseous muscles. - This infection presents as diffuse swelling and tenderness in the central palm, often with pain on passive extension of the fingers, but does not involve the fingertip pulp directly.

Q: Which of the following is the most common site for intra-abdominal abscesses?

Pelvis. ***Pelvis*** - The **pelvis** is the most common site for intra-abdominal abscesses, particularly in ambulatory patients. - As the most gravity-dependent part of the peritoneal cavity, infected fluid naturally collects here. - **Pelvic abscesses** commonly result from appendicitis, diverticulitis, pelvic inflammatory disease, or postoperative complications. - Clinical features include pelvic pain, tenesmus, urinary symptoms, and fever. *Paracolic* - **Paracolic gutters** serve as pathways for fluid spread along the lateral aspects of the ascending and descending colon. - While infected fluid tracks through these gutters, it typically pools in dependent areas (pelvis or subphrenic spaces) rather than remaining in the gutters. - They are conduits rather than final collection sites. *Subphrenic* - **Subphrenic abscesses** occur beneath the diaphragm and are the second most common site. - Often associated with upper GI perforations, hepatobiliary surgery, or splenic procedures. - Present with shoulder tip pain, pleural effusion, and lower chest signs. *Retroperitoneal* - **Retroperitoneal abscesses** originate from retroperitoneal structures (kidneys, pancreas, psoas). - Less common than intraperitoneal abscesses. - Require CT imaging for diagnosis and often need percutaneous or surgical drainage.

Q: Kanavel's sign is seen in:

Flexor tendon sheath infectious inflammation in the hand. ***Flexor tendon sheath infectious inflammation in the hand*** - **Kanavel's signs** are a set of four clinical findings highly indicative of **flexor tenosynovitis** (infection of the flexor tendon sheath) in the hand. - These signs include **uniform swelling of the affected digit**, **flexed posturing of the affected digit**, **exquisite tenderness along the course of the flexor tendon sheath**, and **pain with passive extension of the affected digit**. *Mid palmar space abscess* - A **mid palmar space abscess** is a localized collection of pus in the central compartment of the hand and typically presents with **diffuse palmar swelling** and **tenderness**, not the specific findings of Kanavel's signs limited to a single digit. - While it can cause significant pain and restricted movement, it does not involve the flexor tendon sheath of a single digit in a way that elicits all four Kanavel's signs. *Ulnar bursa* - Inflammation/infection of the **ulnar bursa** (the common flexor sheath) can involve multiple digits, particularly the small finger and thumb if it communicates with the radial bursa, but the presentation is usually a more **diffuse swelling** of the palm and digits, not the isolated, characteristic signs of Kanavel's affecting a single digit. - Pain and swelling may be more generalized across the palm, and Kanavel's signs are specific to a single, infected flexor tendon sheath. *Web space involvement* - **Web space infections** occur in the loose connective tissue between the metacarpal heads in the interdigital spaces, presenting as **swelling** and **tenderness localized to the web space**. - This condition does not directly involve the flexor tendon sheath of a digit and therefore does not produce the specific clinical signs described by Kanavel.

Q: The best method to prevent gas gangrene in a 45-year-old female who has been brought to the emergency room with a crush injury of the thigh following a motor vehicle accident is

Extensive wound debridement. ***Extensive wound debridement*** - **Debridement** removes **necrotic tissue** and foreign bodies, eliminating the anaerobic environment and substrate upon which *Clostridium perfringens* thrives. - This direct removal of contaminated tissue is the most effective way to prevent the proliferation of anaerobic bacteria responsible for **gas gangrene**. *Hyperbaric oxygen therapy* - While **hyperbaric oxygen therapy** can be a useful adjuvant treatment once **gas gangrene** is established, it is not the primary preventative measure. - It creates a hyperoxic environment toxic to anaerobes and aids tissue healing, but it does not address the initial wound contamination. *Gas gangrene prophylaxis serum* - There is currently **no effective or routinely used gas gangrene prophylaxis serum** or antitoxin for prevention. - Antitoxins are more relevant in treating established toxemia, and their prophylactic use is not standard practice due to limited efficacy and potential side effects. *Tetanus prophylaxis* - **Tetanus prophylaxis** (e.g., tetanus toxoid vaccine, TIG) is crucial for crush injuries due to the risk of *Clostridium tetani* infection, but it does not prevent gas gangrene. - Tetanus and gas gangrene are caused by different clostridial species with distinct pathological mechanisms and require different prophylactic approaches.

Q: What is the term for bacteria that are actively dividing and have invaded the wound surface in the context of surgical site infection?

Infection. ***Infection*** - This term precisely describes bacteria that are **actively dividing** and have **invaded the host tissue**, causing a clinical infection with tissue damage and host immune response. - In surgical site infections, this represents the stage where microorganisms have overcome host defenses and are causing disease. - This is the standard terminology used in surgical literature to describe the progression from contamination to active disease. *Contamination* - **Contamination** refers to the presence of microorganisms on a surface or in a wound without active proliferation or host response. - It's an early stage where bacteria are present but not yet multiplying or causing disease. *Colonization* - **Colonization** indicates that microorganisms are replicating on the host surface or in a wound without tissue invasion or causing an immune response. - Unlike infection, colonization does not involve invasion of tissue or clinical signs of disease. *Local infection* - While this describes an infection confined to a particular anatomical area, it is a descriptor of the **location** rather than the **process** described in the question. - The question asks specifically about the term for dividing and invading bacteria, which is simply "infection" - the word "local" adds information about location but doesn't define the fundamental process.

Q: What is the most common infection that occurs after splenectomy?

Pneumococcus. ***Pneumococcus*** - Patients who have undergone a splenectomy are at significantly increased risk of developing **overwhelming post-splenectomy infection (OPSI)**, with *Streptococcus pneumoniae* (Pneumococcus) being the most common causative organism. - The spleen plays a crucial role in clearing **encapsulated bacteria**, and its absence leaves the individual vulnerable to these infections. *Meningococcus* - While *Neisseria meningitidis* (Meningococcus) is also an encapsulated bacterium and can cause severe infections in asplenic patients, it is **less common** than Pneumococcus as the primary cause of OPSI. - Vaccination against Meningococcus is recommended for splenectomized patients, but *Pneumococcus* remains the leading concern. *Staphylococcus* - *Staphylococcus* species, such as *Staphylococcus aureus*, are common causes of various infections but are generally **not encapsulated bacteria** in the same way *Streptococcus pneumoniae* is. - The spleen's primary role in clearing encapsulated organisms means that *Staphylococcus* infections are **not the most common or characteristic** post-splenectomy infection. *Corynebacterium* - *Corynebacterium* species are typically associated with infections like **diphtheria** or **opportunistic infections** in immunocompromised individuals. - They are **not encapsulated bacteria** and do not represent the most common encapsulated bacterial infection seen after splenectomy.

Question 1

Which of the following is an example of a clean surgery?

Accepted Answer

Hernia surgery

Answer

Cholecystectomy

Answer

Rectal surgery

Answer

Gastric surgery

Question 2

Most common organism causing infection after an open fracture?

Accepted Answer

Staphylococcus aureus

Answer

Klebsiella

Answer

Pseudomonas

Answer

Gonococcus

Question 3

What is the most common complication of a felon?

Accepted Answer

Osteomyelitis

Answer

Subungual hematoma

Answer

Infective arthritis

Answer

No complications

Question 4

What is a felon or whitlow?

Accepted Answer

Terminal pulp space infection

Answer

Infection of the ulnar bursa

Answer

Infection of the radial bursa

Answer

Midpalmar space infection

Question 5

In a contaminated, punctured wound of the leg of a non-immune child of 10, which one of the following measures would provide the best protection against the development of tetanus?

Accepted Answer

Active and passive immunization along with antibiotics

Answer

Active immunization and antibiotics

Answer

Active immunization, wound excision and primary closure

Answer

Active immunization, antibiotics and immobilisation

Question 6

Which of the following is the most common site for intra-abdominal abscesses?

Accepted Answer

Pelvis

Answer

Subphrenic

Answer

Paracolic

Answer

Retroperitoneal

Question 7

Kanavel's sign is seen in:

Accepted Answer

Flexor tendon sheath infectious inflammation in the hand

Answer

Mid palmar space abscess

Answer

Web space involvement

Answer

Ulnar bursa

Question 8

The best method to prevent gas gangrene in a 45-year-old female who has been brought to the emergency room with a crush injury of the thigh following a motor vehicle accident is

Accepted Answer

Extensive wound debridement

Answer

Hyperbaric oxygen therapy

Answer

Gas gangrene prophylaxis serum

Answer

Tetanus prophylaxis

Question 9

What is the term for bacteria that are actively dividing and have invaded the wound surface in the context of surgical site infection?

Accepted Answer

Infection

Answer

Contamination

Answer

Colonization

Answer

Local infection

Question 10

What is the most common infection that occurs after splenectomy?

Accepted Answer

Pneumococcus

Answer

Meningococcus

Answer

Staphylococcus

Answer

Corynebacterium

Surgical Infections — MCQs

Surgical Infections — MCQs

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