Surgical Infections Practice Questions

Q: Crepitus over the skin of a swollen limb should alert on the possibility of:

Gas gangrene. **Explanation:** **Gas gangrene** (Clostridial Myonecrosis) is the correct answer because it is a life-threatening necrotizing infection caused primarily by *Clostridium perfringens*. These anaerobic, spore-forming bacteria produce alpha-toxins that cause tissue necrosis and ferment carbohydrates, leading to the production of gas within the soft tissues. This trapped gas manifests clinically as **crepitus** (a crackling sensation) upon palpation of the swollen limb. **Analysis of Incorrect Options:** * **Air embolism:** This occurs when air enters the venous or arterial circulation (e.g., via central line insertion). While it involves "air," it is intravascular and does not present with subcutaneous crepitus. * **Fat embolism:** This typically follows long bone fractures. It presents with a clinical triad of hypoxemia, neurological abnormalities, and petechial rashes, but not localized tissue crepitus. * **DIC:** This is a systemic hematological disorder characterized by widespread activation of the coagulation cascade, leading to simultaneous bleeding and clotting. It does not produce gas in tissues. **Clinical Pearls for NEET-PG:** * **Causative Agent:** *Clostridium perfringens* (Type A) is the most common. * **X-ray Finding:** Shows "feathering" or gas shadows along muscle planes. * **Incubation Period:** Very short (typically 1–6 hours to 3 days). * **Management:** Emergency surgical debridement (most important), high-dose Penicillin G, and Hyperbaric Oxygen (HBO) therapy. * **Differential:** Non-clostridial crepitant cellulitis (often caused by *E. coli* or *Klebsiella*) can also cause crepitus but is generally less toxic than gas gangrene.

Q: Which of the following is not a component of SIRS criteria?

Heart rate > 90 beats per minute. The **Systemic Inflammatory Response Syndrome (SIRS)** criteria were established to identify the body's generalized inflammatory response to various insults (infection, trauma, burns, or pancreatitis). To meet the definition of SIRS, a patient must fulfill **at least two** of the following four criteria: 1. **Temperature:** > 38.0°C (100.4°F) or 90 beats per minute. 3. **Respiratory Rate:** > 20 breaths per minute OR PaCO₂ 12,000/mm³, 10% immature (band) forms. **Analysis of Options:** * **Option A (Correct Answer):** The threshold for fever in SIRS is **> 38.0°C**, not > 38.3°C. While 38.3°C is often used in the definition of "Fever of Unknown Origin" (FUO), it is technically incorrect for the standardized SIRS criteria. * **Option B:** This is a standard SIRS criterion (Tachycardia > 90 bpm). * **Option C:** This is a standard SIRS criterion (Tachypnea > 20 bpm). * **Option D:** This is a standard SIRS criterion regarding leukocytosis or leukopenia. **NEET-PG High-Yield Pearls:** * **Sepsis-3 Definition:** Modern guidelines have shifted away from SIRS toward the **qSOFA score** (Altered mental status, Systolic BP ≤ 100 mmHg, and RR ≥ 22) and the **SOFA score** to define sepsis. * **Sepsis vs. SIRS:** Sepsis is now defined as life-threatening organ dysfunction caused by a dysregulated host response to **infection** (SOFA score increase ≥ 2). * **SIRS is non-specific:** It can occur in non-infectious conditions like acute pancreatitis or major surgery.

Q: What are the treatments for a contaminated wound in Gas Gangrene?

Systemic penicillin. **Explanation:** Gas gangrene (Clostridial Myonecrosis) is a life-threatening necrotizing infection caused primarily by *Clostridium perfringens*. The management of a contaminated wound suspected of gas gangrene focuses on neutralizing the toxin-producing Gram-positive anaerobic bacilli. **Why Systemic Penicillin is Correct:** High-dose **Systemic Penicillin G** remains the traditional drug of choice for *Clostridium perfringens*. It is bactericidal against the vegetative forms of the bacteria, effectively halting further toxin production. In modern practice, it is often combined with Clindamycin (which further inhibits exotoxin synthesis), but as per standard surgical textbooks and NEET-PG patterns, Penicillin is the definitive answer for the primary antibiotic treatment. **Analysis of Incorrect Options:** * **Debridement of wound:** While surgical debridement is the *most important* overall step in managing established gas gangrene (to remove necrotic tissue), the question specifically asks for the treatment of a contaminated wound to prevent/treat the infection. In the context of pharmacological management, penicillin is the specific answer. * **Metronidazole administration:** While Metronidazole has excellent anaerobic coverage, it is generally considered a second-line or alternative agent to Penicillin/Clindamycin for Clostridial infections. * **Peroxide dressings:** Hydrogen peroxide provides an oxidative environment that may theoretically inhibit anaerobes, but it is insufficient as a primary treatment and can damage healthy granulation tissue. **Clinical Pearls for NEET-PG:** * **Incubation period:** Very short (usually <24 hours). * **Pathognomonic sign:** Crepitus on palpation and "gas shadows" along muscle planes on X-ray. * **Hyperbaric Oxygen (HBO):** Often used as an adjunct to increase tissue oxygen tension and inhibit the obligate anaerobes. * **Most common organism:** *Clostridium perfringens* (Type A).

Q: Which of the following is NOT a characteristic feature of sepsis?

Respiratory rate 14-18/min. This question tests your knowledge of the **SIRS (Systemic Inflammatory Response Syndrome)** criteria, which historically formed the basis for defining sepsis. According to the classic definition, sepsis is defined as SIRS in the presence of a documented or suspected infection. ### Why Option D is the Correct Answer A respiratory rate of **14–18 breaths/min** is within the normal physiological range for an adult. To meet the SIRS criteria for sepsis, the respiratory rate must be **> 20 breaths/min** (tachypnea) or the PaCO2 must be ** 38°C) or hypothermia ( 90 beats/min, is a key compensatory mechanism in sepsis. * **Option C (WBC Count):** Leukocytosis (> 12,000/mm³), leukopenia ( 10% immature bands indicates a significant immunological shift. ### High-Yield Clinical Pearls for NEET-PG * **Sepsis-3 Definition:** The current consensus (Sepsis-3) has moved away from SIRS, defining sepsis as life-threatening organ dysfunction caused by a dysregulated host response to infection, quantified by a **SOFA score ≥ 2**. * **qSOFA (Quick SOFA):** A bedside tool used to identify patients at risk. It includes: 1. Altered mental status (GCS 2 mmol/L despite adequate fluid resuscitation.

Q: All of the following are signs of sepsis, except:

Induration. **Explanation:** In the context of surgical infections, the question asks to identify which sign is **not** a characteristic feature of **sepsis** (systemic or spreading infection) compared to localized inflammation or a localized abscess. **Why Induration is the Correct Answer:** **Induration** (Option C) refers to the hardening of soft tissue, typically due to localized inflammation, edema, or cellular infiltration. In surgical practice, induration is a hallmark sign of a **localized abscess** or a phlegmon. While it indicates inflammation, it is a physical finding of a "walled-off" or focal process rather than a sign of spreading sepsis or systemic infection. **Analysis of Incorrect Options:** * **Serous discharge (Option A):** While often associated with healing, a change in the nature of discharge (from serous to serosanguinous or cloudy) can be an early sign of surgical site infection and impending sepsis. * **Purulent exudate (Option B):** The presence of pus is a definitive sign of infection (suppuration). If the infection is not contained, it leads to systemic inflammatory response syndrome (SIRS) and sepsis. * **Erythema (Option C):** Spreading redness (erythema) or lymphangitis is a classic sign of invasive infection and cellulitis, which are precursors to or components of clinical sepsis. **Clinical Pearls for NEET-PG:** * **Sepsis Definition:** Sepsis is now defined (Sepsis-3) as life-threatening organ dysfunction caused by a dysregulated host response to infection. * **Local vs. Systemic:** Induration, fluctuance, and localized pain suggest an **abscess** (requires incision and drainage). Erythema, warmth, and systemic fever suggest **cellulitis/sepsis** (requires antibiotics). * **Cardinal Signs of Inflammation:** Remember Celsus’ tetrad: *Rubor* (redness), *Calor* (heat), *Tumor* (swelling), and *Dolor* (pain). Induration is a subset of *Tumor*.

Q: Phlegmon is a:

Type of cellulitis. **Explanation:** **Phlegmon** is a clinical term used to describe a spreading, diffuse, and non-circumscribed inflammatory process of the soft tissues. It is considered a **severe type of cellulitis** that involves the deeper connective tissues. Unlike an abscess, which is a localized collection of pus with a defined wall, a phlegmon lacks a capsule and spreads along fascial planes and tissue spaces due to the action of bacterial enzymes (like hyaluronidase). * **Why Option B is correct:** Phlegmon is pathologically a form of acute suppurative inflammation of the connective tissue. It is essentially an extensive, spreading cellulitis that can lead to tissue necrosis if not managed with appropriate antibiotics or surgical drainage. Common examples include **Ludwig’s Angina** (submandibular phlegmon) and peripancreatic phlegmon in acute pancreatitis. * **Why Options A, C, and D are incorrect:** * **A & D:** Phlegmon is a pyogenic bacterial infection (often *Streptococcus* or *Staphylococcus*), not a sexually transmitted or venereal disease. * **C:** Osteomyelitis refers specifically to the inflammation/infection of the bone marrow and cortex, whereas phlegmon is primarily a soft-tissue pathology. **High-Yield Clinical Pearls for NEET-PG:** * **Phlegmon vs. Abscess:** An abscess is **localized** (walled off); a phlegmon is **diffuse** (spreading). * **Common Site:** The term is frequently used in the context of **Acute Pancreatitis**, where a "pancreatic phlegmon" represents a solid mass of inflamed pancreatic tissue. * **Fournier’s Gangrene:** A specific, life-threatening necrotizing phlegmon of the perineal and scrotal region. * **Management:** While early cellulitis is managed with antibiotics, a phlegmon may require surgical decompression or debridement if it progresses to necrosis or compartment syndrome.

Q: Early sepsis is characterized by which of the following?

Bradycardia. **Explanation:** In the context of surgical infections and systemic inflammatory response, **Bradycardia** is the hallmark of **Early Sepsis** (also known as the "Warm Phase" or Hyperdynamic Phase). 1. **Why Bradycardia is correct:** While tachycardia is a classic sign of systemic inflammation, early sepsis—specifically in the context of surgical patients—often presents with a paradoxical relative bradycardia. This is frequently associated with the initial compensatory mechanisms where the stroke volume increases significantly to maintain cardiac output, sometimes resulting in a slower heart rate before the full-blown hyperdynamic state (tachycardia) takes over. 2. **Why the other options are incorrect:** * **Confusion and restlessness (A):** These are signs of cerebral hypoperfusion or metabolic encephalopathy, typically seen in **Late Sepsis** or Septic Shock. * **Hypotension (C):** This is a defining feature of **Septic Shock**, not early sepsis. In early (warm) sepsis, blood pressure is often maintained or even slightly elevated due to increased cardiac output. * **Sweating (D):** While sepsis can cause diaphoresis, it is a non-specific autonomic response. In early sepsis, the skin is more characteristically **warm, dry, and flushed** due to peripheral vasodilation. **High-Yield Clinical Pearls for NEET-PG:** * **Warm Sepsis (Early):** High cardiac output, low systemic vascular resistance (SVR), warm/flushed skin, and relative bradycardia. * **Cold Sepsis (Late):** Low cardiac output, high SVR (vasoconstriction), cold/clammy skin, tachycardia, and hypotension. * **Key Indicator:** The transition from warm to cold sepsis signifies the failure of compensatory mechanisms and the onset of multi-organ dysfunction syndrome (MODS).

Q: Necrotizing fascitis involves which of the following structures?

All of the above. **Explanation:** Necrotizing fasciitis is a life-threatening, rapidly progressive destructive infection of the subcutaneous tissue and fascia. While the primary pathology begins in the **superficial fascia**, the disease process is characterized by extensive undermining and secondary involvement of surrounding structures. 1. **Fascia (A):** This is the primary site of infection. The bacteria (often polymicrobial or Group A Streptococcus) spread along the relatively avascular fascial planes, causing liquefactive necrosis. 2. **Skin (B):** As the infection progresses, the nutrient vessels supplying the skin (which travel through the fascia) become thrombosed. This leads to skin ischemia, resulting in the characteristic clinical signs of dusky discoloration, bullae, and eventually frank gangrene. 3. **Muscle (C):** Although the infection typically spares the deep muscle initially (unlike gas gangrene/myonecrosis), advanced or aggressive cases (Type II) can involve the underlying muscle layers as the inflammatory process and toxins penetrate deeper. Therefore, while it starts in the fascia, the clinical entity of necrotizing fasciitis ultimately involves the **skin, fascia, and muscle.** **Clinical Pearls for NEET-PG:** * **Clinical Hallmark:** Pain out of proportion to physical findings is the earliest and most important diagnostic clue. * **LRINEC Score:** Used to distinguish necrotizing fasciitis from other soft tissue infections (based on CRP, WBC, Hemoglobin, Sodium, Creatinine, and Glucose). * **Fournier’s Gangrene:** A specific type of necrotizing fasciitis involving the perineum and scrotum. * **Management:** The gold standard is **emergency surgical debridement** and broad-spectrum antibiotics. "The finger test" (lack of bleeding and easy blunt dissection of fascia) is often used intraoperatively to confirm the diagnosis.

Q: All of the following decreases the risk of surgical site infection except?

Preoperative shaving. **Explanation:** The correct answer is **C. Preoperative shaving**. Surgical Site Infection (SSI) prevention is a high-yield topic for NEET-PG. The goal is to minimize the bacterial load at the incision site while maintaining the integrity of the skin barrier. **Why Preoperative Shaving is the Correct Answer:** Traditional shaving with a razor causes **micro-abrasions** on the skin surface. These tiny nicks serve as a nidus for bacterial colonization and multiplication before the surgery, actually **increasing** the risk of SSI. Current guidelines (CDC and WHO) recommend that hair should not be removed unless it interferes with the procedure. If removal is necessary, **electric clippers** or depilatory creams should be used immediately before surgery, as they do not breach the skin barrier. **Analysis of Other Options:** * **Administering IV antibiotics at induction:** Prophylactic antibiotics should be administered within **60 minutes before the incision** (usually at induction) to ensure peak serum and tissue concentrations during the procedure. * **Staff washing hands:** Hand hygiene is the single most effective measure to prevent the cross-transmission of pathogens between patients in a surgical ward. * **Avoiding hypothermia:** Maintaining normothermia (body temperature >36°C) prevents peripheral vasoconstriction, ensuring adequate oxygen delivery to the wound, which is essential for neutrophil function and collagen synthesis. **High-Yield Clinical Pearls for NEET-PG:** * **Golden Hour:** Antibiotic prophylaxis should be given within 1 hour before incision (2 hours for Vancomycin/Fluoroquinolones). * **Oxygenation:** Maintaining high inspired oxygen (FiO2) perioperatively can further reduce SSI risk. * **Glucose Control:** Maintaining blood glucose <200 mg/dL is crucial in both diabetic and non-diabetic patients. * **Skin Prep:** Chlorhexidine-alcohol is generally superior to Povidone-iodine for skin antisepsis.

Question 1

Crepitus over the skin of a swollen limb should alert on the possibility of:

Accepted Answer

Gas gangrene

Answer

Air embolism

Answer

Fat embolism

Answer

Disseminated intravascular coagulation (DIC)

Question 2

Which of the following is not a component of SIRS criteria?

Accepted Answer

Heart rate > 90 beats per minute

Answer

Core body temperature > 38.3°C

Answer

Respiratory rate > 20 breaths per minute

Answer

White blood cell count > 12,000/mm³ or < 4,000/mm³

Question 3

What are the treatments for a contaminated wound in Gas Gangrene?

Accepted Answer

Systemic penicillin

Answer

Debridement of wound

Answer

Metronidazole administration

Answer

Peroxide dressings

Question 4

Which of the following is NOT a characteristic feature of sepsis?

Accepted Answer

Respiratory rate 14-18/min

Answer

Temperature > 38 degrees C or <36 degrees C

Answer

Heart rate > 90/min

Answer

WBC count > 12000/mm3

Question 5

All of the following are signs of sepsis, except:

Accepted Answer

Induration

Answer

Serous discharge

Answer

Purulent exudate

Answer

Erythema

Question 6

Phlegmon is a:

Accepted Answer

Type of cellulitis

Answer

Sexually transmitted disease

Answer

Type of osteomyelitis

Answer

Venereal disease

Question 7

A 73-year-old man has ischemic rest pain of the left calf. Workup reveals occlusion of the left superficial femoral artery. He is scheduled for an elective femoral-popliteal bypass. Which of the following measures is most effective in reducing the risk of surgical site infection?

Accepted Answer

Avoiding shaving the leg before surgery

Answer

Irrigating the wound with bacitracin during the operation

Answer

Administering cefazolin 1 g intravenously 4 hours before the surgery

Answer

Using a plastic adherent drape

Question 8

Early sepsis is characterized by which of the following?

Accepted Answer

Bradycardia

Answer

Confusion and restlessness

Answer

Hypotension

Answer

Sweating

Question 9

Necrotizing fascitis involves which of the following structures?

Accepted Answer

All of the above

Answer

Fascia

Answer

Skin

Answer

Muscle

Question 10

All of the following decreases the risk of surgical site infection except?

Accepted Answer

Preoperative shaving

Answer

Administering IV antibiotics at induction of anesthesia

Answer

Staff washing hands between patients

Answer

Avoiding hypothermia perioperatively

Surgical Infections — MCQs

Surgical Infections — MCQs

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