Surgical Infections Practice Questions

Q: Which of the following is FALSE regarding cellulitis?

Abscesses should be managed conservatively. **Explanation:** Cellulitis is a common bacterial skin infection characterized by spreading inflammation of the dermis and subcutaneous tissues. **Why Option D is the Correct (False) Statement:** The fundamental surgical principle for any **abscess** (a localized collection of pus) is **Incision and Drainage (I&D)**. Abscesses cannot be managed conservatively with antibiotics alone because the necrotic core and acidic environment of the pus cavity prevent adequate antibiotic penetration. If an abscess complicates cellulitis, it must be drained surgically to achieve source control. **Analysis of Other Options:** * **Option A:** **Streptococcus pyogenes** (Group A Strep) is the most common causative organism, followed by *Staphylococcus aureus*. Strep produces enzymes like hyaluronidase that facilitate the rapid, "spreading" nature of the infection. * **Option B:** Cellulitis can lead to **SIRS** (fever, tachycardia, leukocytosis) if the infection becomes systemic. If left untreated, it can progress to sepsis or necrotizing fasciitis. * **Option C:** By definition, cellulitis is an acute, spreading infection of the **deep dermis and subcutaneous fat**, distinguishing it from Erysipelas, which is more superficial and involves upper dermal lymphatics. **Clinical Pearls for NEET-PG:** * **Erysipelas vs. Cellulitis:** Erysipelas has well-defined, raised borders (milestone sign), whereas cellulitis has ill-defined, non-raised borders. * **Orbital Cellulitis:** A surgical emergency; look for proptosis and restricted eye movements. * **Treatment:** Elevation of the limb and systemic antibiotics (e.g., Flucloxacillin or Cephalosporins). If MRSA is suspected, use Vancomycin or Linezolid.

Q: A soldier injured in combat presents with edema, crepitus, and a brown exudate. What is the most likely diagnosis?

Gas gangrene. **Explanation:** The clinical presentation of **edema, crepitus, and a brown exudate** (often described as "dishwater" or "sweetly foul-smelling" discharge) in the context of a combat injury is the classic triad for **Gas Gangrene** (Clostridial Myonecrosis). 1. **Why Gas Gangrene is correct:** This is a life-threatening muscle infection caused primarily by *Clostridium perfringens*. In traumatic or combat wounds, anaerobic conditions allow these bacteria to proliferate. They produce alpha-toxins that cause extensive myonecrosis. The **crepitus** is a hallmark sign, resulting from gas production by the bacteria within the soft tissues. The **brown exudate** represents liquefied muscle and hemolyzed blood. 2. **Why other options are incorrect:** * **Crush Syndrome:** This involves systemic manifestations (like acute kidney injury due to myoglobinuria) following prolonged compression of muscle groups. While edema occurs, it does not typically present with crepitus or a specific brown exudate unless secondary infection sets in. * **Long bone fracture:** While common in combat, a fracture alone presents with deformity, bony crepitus (different from soft-tissue gas crepitus), and localized pain, but not the characteristic infectious exudate. **High-Yield Clinical Pearls for NEET-PG:** * **Causative Agent:** *Clostridium perfringens* (Gram-positive, spore-forming anaerobic bacilli) is the most common (80%). * **Incubation Period:** Very short, typically **12–24 hours**. * **X-ray finding:** Shows "feathery" patterns of gas in muscle planes. * **Management:** Emergency surgical debridement (fasciotomy/amputation), high-dose Penicillin G, and Hyperbaric Oxygen (HBO) therapy. * **Distinction:** Unlike necrotizing fasciitis, gas gangrene primarily involves the **muscle** (myonecrosis).

Q: Following a small-bowel resection, a 49-year-old male develops fever and anemia. The surface surrounding the surgical wound is warm to the touch and necrotizing fasciitis is suspected. What clinical manifestation would most suggest necrotizing fasciitis?

Severe pressure-like pain. **Explanation:** The diagnosis of **Necrotizing Fasciitis (NF)** is primarily clinical, and the hallmark sign is **pain out of proportion to physical findings**. While erythema and swelling may appear mild or resemble simple cellulitis, the underlying destruction of the fascia and deep tissues causes intense, severe pressure-like pain. As the infection progresses and destroys cutaneous nerves, this pain may eventually transition into anesthesia (numbness), which is also a late, specific sign. **Analysis of Options:** * **C. Severe pressure-like pain (Correct):** This is the earliest and most reliable clinical indicator. The infection spreads rapidly along the deep fascial planes, creating high-pressure inflammatory edema before significant skin changes occur. * **A. Erythema & D. Swelling:** These are common in almost all surgical site infections (SSIs) and superficial cellulitis. They lack the specificity required to differentiate NF from less severe infections. * **B. Leukocytosis:** While typically present in NF, an elevated white cell count is a non-specific systemic response to any infection, inflammation, or the stress of surgery itself. **High-Yield Clinical Pearls for NEET-PG:** * **Hard Signs of NF:** Crepitus (gas in tissues), skin necrosis/bullae, and "dishwater pus" (thin, foul-smelling discharge). * **LRINEC Score:** Used to differentiate NF from cellulitis based on laboratory markers (CRP, WBC, Hemoglobin, Sodium, Creatinine, Glucose). * **Treatment:** NF is a surgical emergency. The definitive management is **immediate and aggressive surgical debridement**, not just antibiotics. * **Type I NF:** Polymicrobial (most common); **Type II NF:** Monomicrobial (Group A Streptococcus).

Q: Which among the following is the most common site of a felon?

Thumb. **Explanation:** A **felon** is an acute, closed-space infection of the pulp space of the distal phalanx. The pulp is divided into numerous small, non-compliant compartments by tough fibrous septa that extend from the skin to the periosteum. **Why the Thumb is Correct:** Statistically, the **thumb** and the **index finger** are the most frequently involved digits in hand infections due to their increased usage and higher frequency of minor trauma (e.g., needle pricks, splinters). Among all digits, the **thumb** is documented as the most common site for a felon. The clinical significance lies in the anatomy: as pressure increases within these tight compartments due to pus formation, it can lead to local ischemia, necrosis, and potentially osteomyelitis of the distal phalanx. **Analysis of Incorrect Options:** * **Index Finger (Option A):** While the index finger is the second most common site, it follows the thumb in frequency. * **Ring Finger (Option B) & Little Finger (Option C):** These digits are less involved in fine motor tasks and repetitive trauma compared to the thumb and index finger, making them less common sites for felon development. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Presentation:** Characterized by severe, throbbing pain, redness, and exquisite tenderness over the pulp. * **Treatment:** Early incision and drainage (I&D) are mandatory. The incision should be made where the tenderness is maximal (usually lateral or volar) to avoid the tactile pad and prevent "fish-mouth" deformity. * **Complication:** If left untreated, it can lead to **osteomyelitis** of the distal phalanx (the most common complication) or a **flexor tenosynovitis** if the infection tracks proximally.

Q: What is true about cellulitis of the lower limb?

Infection of the skin and subcutaneous tissue. **Explanation:** **Cellulitis** is a common bacterial infection characterized by inflammation of the **deep dermis and subcutaneous tissues**. It is most frequently caused by *Streptococcus pyogenes* (Group A Strep) or *Staphylococcus aureus*. **Why Option A is Correct:** The fundamental pathology of cellulitis involves an acute spreading inflammation of the skin and its underlying subcutaneous fat. Unlike an abscess, it is non-circumscribed and spreads through tissue planes, often facilitated by bacterial enzymes like hyaluronidase. **Analysis of Other Options:** * **Option B (Fever and Malaise):** While systemic symptoms *can* occur, they are not universal in simple cellulitis. In many clinical scenarios, the infection remains localized with erythema, warmth, and tenderness without significant systemic upset. * **Option C (Margins):** This is a classic "distractor" for NEET-PG. **Distinct, raised margins** are the hallmark of **Erysipelas** (a more superficial infection involving the upper dermis and superficial lymphatics). In cellulitis, the margins are characteristically **ill-defined and indistinct** because the infection is deeper. * **Option D:** Since margins are not distinct, "All of the above" is incorrect. **High-Yield Clinical Pearls for NEET-PG:** * **Erysipelas vs. Cellulitis:** Erysipelas has sharp borders and involves the superficial dermis; Cellulitis has diffuse borders and involves subcutaneous tissue. * **Commonest Site:** Lower limb (often following a break in the skin or fungal infection like Tinea pedis). * **Milroy’s Disease:** Chronic lymphedema is a major predisposing factor for recurrent cellulitis. * **Treatment:** Elevation of the limb and systemic antibiotics (e.g., Flucloxacillin or Cephalosporins). If MRSA is suspected, Vancomycin or Linezolid is used.

Question 1

Felon/Whitlow is defined as infection of which space?

Accepted Answer

Terminal pulp space infection

Answer

Midpalmar space infection

Answer

Infection of the ulnar bursa

Answer

Infection of the radial bursa

Question 2

Gas in the tissue should be differentiated with which of the following?

Accepted Answer

Clostridium species infection

Answer

Pseudomyxoma peritonei

Answer

Pseudomonas infection

Answer

Non-clostridial infection

Question 3

All of the following statements about Necrotizing fasciitis are true, except?

Accepted Answer

Most common site is perineum followed by trunk and extremities

Answer

Infection of fascia and subcutaneous tissue

Answer

Most commonly caused by Group A beta hemolytic streptococci

Answer

Surgical debridement is mandatory

Question 4

Which of the following is FALSE regarding cellulitis?

Accepted Answer

Abscesses should be managed conservatively

Answer

Caused by Streptococcus pyogenes

Answer

Can cause Systemic Inflammatory Response Syndrome (SIRS)

Answer

Infection of subcutaneous tissue

Question 5

A soldier injured in combat presents with edema, crepitus, and a brown exudate. What is the most likely diagnosis?

Accepted Answer

Gas gangrene

Answer

Crush syndrome

Answer

Long bone fracture

Answer

None of the above

Question 6

Following a small-bowel resection, a 49-year-old male develops fever and anemia. The surface surrounding the surgical wound is warm to the touch and necrotizing fasciitis is suspected. What clinical manifestation would most suggest necrotizing fasciitis?

Accepted Answer

Severe pressure-like pain

Answer

Erythema

Answer

Leukocytosis

Answer

Swelling

Question 7

Which among the following is the most common site of a felon?

Accepted Answer

Thumb

Answer

Index finger

Answer

Ring finger

Answer

Little finger

Question 8

A 40-year-old woman presents with a finger laceration sustained while cooking. Two days post-injury, she develops fever, shaking chills, and painful, mildly erythematous swelling of her hand. Her condition rapidly deteriorates with progressing erythema, development of dusky redness, bullae, and decreased sensation in the hand. What is the most important next step in managing this patient?

Accepted Answer

Surgical consultation and exploration of the wound

Answer

Treatment with clindamycin for mixed aerobic-anaerobic infection

Answer

Treatment with penicillin for clostridial infection

Answer

Vancomycin to cover community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA)

Question 9

What is the infection rate without antibiotic prophylaxis for clean-contaminated surgery?

Accepted Answer

6-9%

Answer

1-2%

Answer

2-5%

Answer

10-15%

Question 10

What is true about cellulitis of the lower limb?

Accepted Answer

Infection of the skin and subcutaneous tissue

Answer

Fever and malaise are common

Answer

Margins are distinct

Answer

All of the above

Surgical Infections — MCQs

Surgical Infections — MCQs

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