Surgical Infections Practice Questions

Q: Apart from Escherichia coli, what is the other most common organism implicated in acute suppurative bacterial peritonitis?

Klebsiella. **Explanation:** Acute suppurative bacterial peritonitis (Secondary Peritonitis) is typically a **polymicrobial infection** resulting from the perforation of a hollow viscus or inflammatory spread from intra-abdominal organs. **Why Klebsiella is correct:** In secondary peritonitis, the flora reflects the site of origin (usually the GI tract). While **Escherichia coli** is the most frequently isolated aerobic Gram-negative organism, **Klebsiella species** (specifically *K. pneumoniae*) rank as the second most common aerobic isolates. These organisms originate from the intestinal microbiota and proliferate rapidly in the peritoneal cavity following a breach in mucosal integrity. **Analysis of Incorrect Options:** * **A. Bacteroides:** While *Bacteroides fragilis* is the most common **anaerobe** isolated in peritonitis, it is generally found in combination with aerobes. In the context of "most common organisms" alongside E. coli, Klebsiella is statistically more frequent in aerobic cultures. * **C. Peptostreptococcus:** This is an anaerobic Gram-positive coccus. While present in polymicrobial intra-abdominal infections, it is less prevalent than E. coli or Klebsiella. * **D. Pseudomonas:** *Pseudomonas aeruginosa* is typically associated with tertiary peritonitis, immunocompromised states, or nosocomial (hospital-acquired) infections rather than primary or common secondary suppurative peritonitis. **High-Yield Clinical Pearls for NEET-PG:** * **Secondary Peritonitis:** Most common type; always polymicrobial (E. coli > Klebsiella > Streptococci > B. fragilis). * **Primary Peritonitis (SBP):** Usually monomicrobial; E. coli is the most common cause in adults with cirrhosis, while *Streptococcus pneumoniae* is common in children with nephrotic syndrome. * **Gold Standard Diagnosis:** Presence of free gas under the diaphragm on an erect X-ray (indicates perforation) and a peritoneal fluid WBC count >250 cells/mm³.

Q: Which of the following statements regarding gas gangrene is TRUE?

Gas is invariably present in the muscle compartments.. ### Explanation **Gas Gangrene (Clostridial Myonecrosis)** is a life-threatening necrotizing infection of the muscle. **Why Option D is Correct:** The hallmark of gas gangrene is the production of gas within the tissues as a byproduct of anaerobic fermentation of muscle carbohydrates. While gas may not always be visible on the skin surface early on, it is **invariably present within the muscle compartments** and fascial planes. This can be detected clinically as crepitus or radiologically as "feathering" of the muscle fibers on an X-ray. **Analysis of Incorrect Options:** * **Option A:** Gas gangrene is primarily caused by **_Clostridium perfringens_** (Type A), not _C. botulinum_ (which causes botulism/paralysis). * **Option B:** Clostridial species are **Gram-positive**, spore-forming, obligate anaerobic bacilli. * **Option C:** The systemic toxicity and tissue destruction are due to the release of **exotoxins**, most notably the **Alpha-toxin (Lecithinase)**, which dissolves cell membranes and causes massive hemolysis. Endotoxins are typically associated with Gram-negative bacteria. **NEET-PG High-Yield Pearls:** * **Incubation Period:** Very short, typically **6 to 48 hours** post-injury. * **Clinical Sign:** The earliest and most reliable symptom is **severe pain out of proportion** to physical findings, accompanied by a "mousy" or "sweetish" odor. * **Diagnosis:** Primarily clinical. Gram stain of wound discharge shows "Box-car" shaped Gram-positive bacilli with a characteristic **absence of polymorphonuclear leucocytes** (due to toxins lysing the WBCs). * **Treatment:** Emergency surgical debridement (fasciotomy/amputation), high-dose Penicillin G, and Hyperbaric Oxygen (HBO) therapy.

Q: Surgical complications of typhoid include all except?

Transverse intestinal ulcer. **Explanation:** The correct answer is **A. Transverse intestinal ulcer**. In Typhoid fever (Enteric fever), the causative organism *Salmonella typhi* targets the **Peyer’s patches** located in the terminal ileum. Since Peyer’s patches are arranged **longitudinally** along the antimesenteric border, the resulting ulcers are also **longitudinal**. In contrast, **transverse ulcers** are characteristic of **Intestinal Tuberculosis**, where the infection spreads via circumferential lymphatics. **Analysis of Options:** * **Intestinal Perforation (B):** This is a classic surgical complication occurring typically in the **3rd week** of infection. It occurs when longitudinal ulcers erode through the serosa, usually in the terminal ileum. * **Paralytic Ileus (C):** This can occur due to severe toxemia or as a secondary response to localized/generalized peritonitis following a micro-perforation. * **Intestinal Hemorrhage (D):** Erosion of small blood vessels at the base of the sloughing Peyer’s patches leads to bleeding, usually during the **2nd or 3rd week**. **High-Yield Clinical Pearls for NEET-PG:** * **Site of Perforation:** Usually within the last **60 cm of the terminal ileum**. * **Pathology:** Typhoid ulcers follow the long axis of the bowel (Longitudinal); Tubercular ulcers follow the short axis (Transverse). * **Widal Test:** Becomes positive in the 2nd week. * **Drug of Choice:** Ceftriaxone is currently preferred for complicated typhoid; Ciprofloxacin was historically the DOC but resistance is now common. * **Surgical Management:** Primary closure (debridement and suturing) is the treatment of choice for perforations if the patient is stable and the perforation is seen early.

Q: Which of the following is not a stage of progression of space infection?

Isolation. **Explanation:** The progression of a surgical space infection (particularly odontogenic or soft tissue infections) follows a predictable clinical timeline based on the host-pathogen interaction. The stages represent the evolution from initial bacterial entry to localized suppuration. **Why "Isolation" is the correct answer:** In the context of surgical infections, **Isolation** is not a recognized stage of progression. While the body attempts to "isolate" an infection via a pyogenic membrane or fibrin wall during the abscess stage, "Isolation" itself is not a formal term used to describe the chronological stages of infection spread. **Analysis of Incorrect Options (The actual stages):** * **Inoculation (0–3 days):** This is the initial stage where bacteria are introduced into the space. It is characterized by soft, mildly tender, and diffuse swelling. Aerobic bacteria predominate here. * **Cellulitis (2–5 days):** As the infection spreads, the area becomes hard (indurated), red, and intensely painful. This is an inflammatory response to the rapid multiplication of both aerobic and anaerobic bacteria. There is no pus at this stage. * **Abscess (4–10 days):** This is the final stage of progression where the center of the infection liquefies. Anaerobes predominate, and clinical signs include **fluctuation** and localized pus formation. **NEET-PG High-Yield Pearls:** * **Sequence:** Inoculation $\rightarrow$ Cellulitis $\rightarrow$ Abscess $\rightarrow$ Resolution/Rupture. * **Cellulitis vs. Abscess:** Cellulitis is diffuse, painful, and lacks fluctuation; an Abscess is localized, less painful than cellulitis, and shows **fluctuation**. * **Microbiology:** Cellulitis is often driven by *Streptococci* (hyaluronidase production helps spread), while Abscesses are often driven by *Staphylococci* or anaerobes. * **Treatment:** Cellulitis is primarily managed with antibiotics; an Abscess requires **Incision and Drainage (I&D)**.

Q: Hilton's method of treatment of an axillary abscess is advised because it:

Protects vital structures. **Explanation:** **Hilton’s Method** is a specialized surgical technique used to drain deep-seated abscesses located in anatomical areas containing vital neurovascular structures (e.g., the axilla, groin, or submandibular region). **1. Why Option A is Correct:** The primary objective of Hilton’s method is to **protect vital structures** (nerves and major blood vessels). In the axilla, the axillary artery, vein, and brachial plexus are at high risk of injury if a sharp scalpel is used deep within the tissue. The technique involves: * Making a superficial skin incision with a scalpel. * Using a **blunt hemostat (sinus forcep)** to pierce the deep fascia and enter the abscess cavity. * Opening the forceps within the cavity and withdrawing them open to enlarge the track. This blunt dissection ensures that vessels and nerves are pushed aside rather than transected. **2. Why Other Options are Incorrect:** * **Option B:** While the method does facilitate drainage, "adequate drainage" can be achieved by many techniques. The *specific* reason for choosing Hilton’s over a standard wide incision is safety, not the volume of drainage. * **Option C:** Hilton’s method does not inherently possess antimicrobial properties to hinder the spread of infection more than any other drainage procedure. * **Option D:** Local instillation of antibiotics is not a standard part of this surgical maneuver and is generally discouraged in favor of systemic therapy and source control. **Clinical Pearls for NEET-PG:** * **Indications:** Axillary abscess, Groin abscess (near femoral vessels), and Ludwig’s Angina (submandibular space). * **Instrument used:** Sinus forceps or Hemostat. * **Key Step:** Always incise the skin **parallel to the skin creases** (Langer’s lines) for better healing, but use blunt dissection for the deep layers.

Q: What is the term for infective gangrene of the subcutaneous tissue that often occurs in the nape of the neck?

Carbuncle. **Explanation:** The correct answer is **Carbuncle**. A carbuncle is an infective gangrene of the subcutaneous tissue caused by *Staphylococcus aureus*. It typically occurs in areas where the skin is thick and inelastic, such as the **nape of the neck** or the back. The infection spreads horizontally in the subcutaneous fat, limited by vertical fibrous septa, leading to multiple points of suppuration (the classic **"sieve-like"** or **"cribriform"** appearance). **Analysis of Options:** * **Boil/Furuncle (Options A & B):** These terms are synonymous. A furuncle is an acute staphylococcal infection of a single hair follicle and its associated sebaceous gland. It is more superficial and localized compared to a carbuncle. * **Impetigo (Option D):** This is a highly contagious, superficial skin infection (epidermal layer) characterized by honey-colored crusting, usually caused by *Streptococcus pyogenes* or *S. aureus*. It does not involve subcutaneous gangrene. **High-Yield Clinical Pearls for NEET-PG:** * **Predisposing Factor:** **Diabetes Mellitus** is the most common underlying condition. Always check urine sugar or HbA1c in a patient with a carbuncle. * **Pathognomonic Sign:** The **cribriform appearance** (multiple discharging sinuses). * **Treatment:** While small carbuncles may respond to antibiotics, the definitive treatment for a mature carbuncle is **cruciate incision and debridement** of all necrotic subcutaneous tissue. * **Common Site:** Nape of the neck and shoulders (due to friction and thick skin).

Question 1

Apart from Escherichia coli, what is the other most common organism implicated in acute suppurative bacterial peritonitis?

Accepted Answer

Klebsiella

Answer

Bacteroides

Answer

Peptostreptococcus

Answer

Pseudomonas

Question 2

Which of the following statements regarding gas gangrene is TRUE?

Accepted Answer

Gas is invariably present in the muscle compartments.

Answer

It is due to Clostridium botulinum infection.

Answer

Clostridial species are gram-negative spore-forming anaerobes.

Answer

The clinical features are due to the release of protein endotoxin.

Question 3

Surgical complications of typhoid include all except?

Accepted Answer

Transverse intestinal ulcer

Answer

Intestinal perforation

Answer

Paralytic ileus

Answer

Intestinal hemorrhage

Question 4

Which of the following is a true statement about sepsis and septic shock?

Accepted Answer

It is the commonest cause of death in surgical patients.

Answer

The main treatment is addressing the infection site.

Answer

It leads to organ dysfunction.

Answer

Antibiotics have no role.

Question 5

Which of the following is not a stage of progression of space infection?

Accepted Answer

Isolation

Answer

Inoculation

Answer

Abscess

Answer

Cellulitis

Question 6

Hilton's method of treatment of an axillary abscess is advised because it:

Accepted Answer

Protects vital structures

Answer

Ensures adequate drainage

Answer

Hinders the spread of infection

Answer

Allows local instillation of antibiotics

Question 7

Which of the following are common causes of non-surgical infections in a surgical patient?

Accepted Answer

Lower respiratory tract infection, Clostridium difficile diarrhea, UTI

Answer

Lower respiratory tract infection, wound infection, Clostridium difficile diarrhea

Answer

Lower respiratory tract infection, UTI

Answer

Wound infection, Clostridium difficile diarrhea, UTI

Question 8

What is the term for infective gangrene of the subcutaneous tissue that often occurs in the nape of the neck?

Accepted Answer

Carbuncle

Answer

Boil

Answer

Furuncle

Answer

Impetigo

Question 9

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 10

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

Surgical Infections — MCQs

Surgical Infections — MCQs

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