Surgical Infections Practice Questions

Q: All of the following are true about pulp space infection EXCEPT?

It is a painless condition. **Explanation:** **Pulp space infection**, commonly known as a **Felon**, is an acute infection of the terminal fatty compartment of the finger. **Why Option B is the correct answer (The Exception):** Pulp space infection is **exceedingly painful**, not painless. The pulp of the finger is divided into numerous small, non-compliant compartments by tough fibrous vertical septa that extend from the periosteum of the distal phalanx to the skin. When infection occurs, inflammatory edema causes a rapid rise in pressure within these closed compartments. This high tension compresses the local nerve endings, resulting in **severe, throbbing pain** and exquisite tenderness. **Analysis of other options:** * **Option A:** "Felon" is the standard clinical synonym for a pulp space infection. * **Option D:** The anatomy of the pulp consists of **vertical fibrous septa** that create multiple small "honeycombed" compartments. This anatomical arrangement is responsible for localizing the infection and increasing pressure. * **Option C:** If left untreated, the high pressure can occlude the small vessels (digital artery branches) supplying the distal phalanx. This leads to **ischemic necrosis** of the pulp and can progress to **osteomyelitis** of the terminal phalanx. **Clinical Pearls for NEET-PG:** * **Management:** The primary treatment is **Incision and Drainage (I&D)**. The incision should be made where the tension is maximal (usually lateral) to avoid scarring on the tactile surface. * **Complication:** The most common bony complication is **sequestration of the distal phalanx** (the epiphysis is usually spared in children because the blood supply to the base of the phalanx arises proximal to the pulp space). * **Key Sign:** The patient often holds the finger in a dependent position to relieve the throbbing sensation.

Q: What is the primary treatment for clostridial myonecrosis?

Penicillin. **Explanation:** **Clostridial myonecrosis**, commonly known as **Gas Gangrene**, is a life-threatening muscle infection primarily caused by *Clostridium perfringens*. This gram-positive, anaerobic, spore-forming bacillus produces potent exotoxins (specifically Alpha-toxin) that cause rapid tissue necrosis and systemic toxicity. **Why Penicillin is Correct:** High-dose **Penicillin G** remains the drug of choice for *Clostridium* species. It effectively inhibits cell wall synthesis in these anaerobic organisms. In modern clinical practice, it is often combined with **Clindamycin**, which is added for its ability to inhibit bacterial protein synthesis and suppress the production of the lethal alpha-toxins. **Why Other Options are Incorrect:** * **Amikacin and Gentamicin (Options A & D):** These are Aminoglycosides. Aminoglycosides are ineffective against anaerobes because their uptake into the bacterial cell is an oxygen-dependent process. They are primarily used for Gram-negative aerobic infections. * **Ampicillin (Option C):** While Ampicillin is a broad-spectrum penicillin, Penicillin G is more potent against *Clostridium* and remains the gold standard for targeted therapy in gas gangrene. **High-Yield Clinical Pearls for NEET-PG:** 1. **Gold Standard Treatment:** The most critical step is **emergency surgical debridement** (radical excision of dead tissue). Antibiotics are adjunctive. 2. **Clinical Sign:** Presence of **crepitus** on palpation and "dishwater" discharge with a sweet, mousy odor. 3. **X-ray Finding:** Characteristic "feathering" pattern of gas in muscle planes. 4. **Hyperbaric Oxygen (HBO):** Often used as an adjunct to increase tissue oxygen tension, which is lethal to the anaerobic *Clostridia*.

Q: What is the best treatment for gas gangrene?

Debridement with IV penicillin. **Explanation:** Gas gangrene (Clostridial Myonecrosis) is a life-threatening, rapidly progressive infection caused primarily by *Clostridium perfringens*. The management strategy is built on the principle that this is a surgical emergency requiring both mechanical removal of necrotic tissue and targeted antimicrobial therapy. **Why Option C is Correct:** The cornerstone of treatment is **emergency surgical debridement** (to remove the anaerobic environment and necrotic muscle) combined with **high-dose IV Penicillin G**. Penicillin remains the drug of choice because *Clostridia* are highly sensitive to it. Often, Clindamycin is added to inhibit the production of bacterial exotoxins, but the standard "best" answer in surgical textbooks remains debridement plus Penicillin. **Analysis of Incorrect Options:** * **Option A:** While debridement is the most critical step, surgery alone is insufficient. Antibiotics are mandatory to control the systemic spread of the infection. * **Option B:** Tetanus toxoid/antitoxin is used for prophylaxis against *Clostridium tetani*. While wound management includes tetanus prophylaxis, it does not treat the active myonecrosis caused by *C. perfringens*. * **Option C:** Polyvalent antitoxin (Gas Gangrene Antitoxin) was historically used but is now considered **ineffective** and is no longer recommended in modern clinical practice due to high risk of serum sickness and lack of proven benefit. **High-Yield NEET-PG Pearls:** * **Clinical Sign:** "Crepitus" on palpation and "Dishwater pus" (serosanguinous discharge) with a sickly sweet odor. * **X-ray Finding:** Feather-like appearance of muscles due to gas (CO2 and H2) between muscle fibers. * **Hyperbaric Oxygen (HBO):** Often used as an adjunct to increase tissue oxygen tension, which is lethal to anaerobic *Clostridia*. * **Incubation Period:** Very short, typically < 24 hours.

Q: Which statement regarding antibiotic prophylaxis is true?

Antibiotic prophylaxis is indicated for colorectal surgery.. ### Explanation **1. Why Option C is Correct:** The primary goal of antibiotic prophylaxis is to reduce the incidence of Surgical Site Infections (SSI) by ensuring therapeutic drug levels in the tissue at the time of incision. **Colorectal surgery** is classified as **Clean-Contaminated** (or Contaminated if there is spillage), involving entry into a colonized viscus with a high bacterial load (anaerobes and Gram-negative bacilli). Prophylaxis is mandatory here as it significantly reduces the high baseline risk of infection. **2. Why Other Options are Incorrect:** * **Option A:** Antibiotic prophylaxis **is indicated** for all clean-contaminated surgeries (e.g., cholecystectomy, elective GI surgery) and certain clean surgeries involving implants or prosthetics. * **Option B:** Gastric ulcer surgery is a **Clean-Contaminated** procedure. While the stomach is normally sterile due to acid, conditions like gastric ulcers, malignancy, or use of H2 blockers increase bacterial colonization, making prophylaxis necessary. * **Option D:** Local irrigation with antibiotics is **not contraindicated**; in fact, it is sometimes used as an adjunct in heavily contaminated wounds (e.g., peritonitis), though it does not replace the need for systemic administration. **3. NEET-PG High-Yield Pearls:** * **Timing:** The most crucial factor. Antibiotics must be administered **within 60 minutes before the skin incision** (except Vancomycin/Fluoroquinolones, which require 120 minutes). * **Duration:** A single preoperative dose is usually sufficient. It should **not exceed 24 hours** postoperatively for most procedures. * **Wound Classification & Prophylaxis:** * **Clean:** No prophylaxis (unless implant/prosthesis used). * **Clean-Contaminated:** Prophylaxis indicated. * **Contaminated/Dirty:** Requires **therapeutic** antibiotics (treatment, not just prophylaxis).

Q: What is the required treatment for acute lymphangitis?

Antibiotics and rest. **Explanation:** **Acute Lymphangitis** is a non-suppurative inflammation of the lymphatic channels, most commonly caused by **Streptococcus pyogenes** (Group A Strep) or occasionally *Staphylococcus aureus*. It typically presents as painful, red, linear streaks extending from a site of infection toward regional lymph nodes. **Why Option A is correct:** The mainstay of treatment is **conservative medical management**. Because the underlying cause is bacterial, systemic **antibiotics** (usually penicillin-based or cephalosporins) are mandatory to prevent progression to bacteremia or sepsis. **Rest** and elevation of the affected limb help reduce edema and facilitate lymphatic drainage, while warm compresses aid in local circulation and pain relief. **Why the other options are wrong:** * **Option B (Lymphangiography):** This is a diagnostic imaging modality used to visualize lymph vessels. It is contraindicated in acute infection as it is invasive and provides no therapeutic benefit. * **Option C (Multiple Incisions):** This is a historical error. Acute lymphangitis is a non-suppurative spreading infection; making incisions is unnecessary and harmful unless a localized abscess has formed. It can lead to further spread of the pathogen. * **Option D (No treatment):** Untreated lymphangitis can rapidly progress to cellulitis, abscess formation, or life-threatening systemic sepsis. **NEET-PG High-Yield Pearls:** * **Clinical Sign:** Look for the "red streak" extending proximally. * **Commonest Organism:** *Streptococcus pyogenes*. * **Differential:** Do not confuse with **Thrombophlebitis**, where the "cord" is palpable and streaks are absent. * **Complication:** If untreated, it leads to **lymphadenitis** (inflammation of the regional nodes).

Q: Tetanus is usually noticed in which type of cases?

Wounds contaminated with faecal matter. **Explanation:** The correct answer is **B. Wounds contaminated with faecal matter.** **Why it is correct:** Tetanus is caused by *Clostridium tetani*, an obligate anaerobic, Gram-positive, spore-forming bacillus. The natural habitat of these spores is soil and the **intestinal tracts of animals and humans**. Therefore, faeces are a primary reservoir for the organism. Wounds contaminated with faecal matter provide both the inoculum and the necessary anaerobic environment (due to tissue necrosis or co-infection with aerobic bacteria) for the spores to germinate and release **tetanospasmin**, the potent neurotoxin responsible for the clinical manifestations of tetanus. **Analysis of Incorrect Options:** * **A. Burn cases:** While tetanus can occur in burns (especially deep, neglected ones), it is less common than in contaminated traumatic wounds. * **C. Open fractures:** These are "tetanus-prone" wounds due to soil contamination and tissue devitalization, but they are statistically less likely to harbor the high concentration of spores found in faecal matter. * **D. Gunshot wounds:** These create anaerobic tracts and contain foreign bodies (wadding/clothing), making them high-risk, but they are not the primary source of the pathogen itself compared to faecal contamination. **Clinical Pearls for NEET-PG:** * **Tetanospasmin:** Acts by blocking the release of inhibitory neurotransmitters (**GABA and Glycine**) from Renshaw cells in the spinal cord, leading to spastic paralysis. * **Incubation Period:** Typically 3–21 days; a shorter incubation period usually correlates with a poorer prognosis. * **First Sign:** Trismus (lockjaw) due to masseter spasm is the most common presenting symptom. * **Management:** Wound debridement is crucial to remove the anaerobic niche. Metronidazole is the preferred antibiotic (over Penicillin G) as Penicillin is a GABA antagonist and may potentiate spasms.

Q: Periosteal reaction in a case of acute osteomyelitis can be seen earliest at:

10 days. **Explanation:** In **Acute Hematogenous Osteomyelitis**, the diagnosis is primarily clinical in the early stages because radiographic changes lag significantly behind the pathological process. **1. Why 10 days is correct:** Radiographic evidence of acute osteomyelitis requires significant bone destruction or periosteal elevation. The **periosteal reaction** (new bone formation under the elevated periosteum) typically becomes visible on a plain X-ray between **10 to 14 days** after the onset of infection. In children, it may appear slightly earlier (around 7–10 days) due to a loose periosteum, but 10 days is the standard textbook milestone for exams. **2. Why other options are incorrect:** * **5 days:** At this stage, X-rays are usually normal or show only subtle **soft tissue swelling** and blurring of fat planes. Bone changes are not yet visible. * **15 & 20 days:** While periosteal reactions are clearly visible by this time, they are not the "earliest" point of detection. By 2–3 weeks, more advanced signs like bone rarefaction and early **sequestrum** formation may begin to appear. **Clinical Pearls for NEET-PG:** * **Earliest Imaging Modality:** **MRI** is the investigation of choice as it can detect changes (marrow edema) within **24–48 hours**. * **Earliest X-ray sign:** Soft tissue swelling (appears within 3–5 days). * **Bone destruction:** At least **30–50% of bone mineral density** must be lost before lucency is visible on a plain radiograph. * **Triple Phase Bone Scan (Technetium-99m):** Shows increased uptake within 48–72 hours but is less specific than MRI. * **Commonest Organism:** *Staphylococcus aureus* across most age groups.

Q: A patient with diffuse severely contaminated peritonitis underwent laparotomy and was left open after surgery. Which of the following might help?

VAC. ***VAC***- **VAC (Vacuum-Assisted Closure)** is the gold standard for managing the damage control abdomen (laparostomy) following severe peritonitis, as it actively drains contaminated fluid and reduces **peritoneal edema**.- By applying controlled **negative pressure**, VAC protects the underlying visceral contents, prevents fascial retraction, and facilitates a definitive delayed primary or secondary fascial closure.*Normal saline soaked gauze*- This traditional method provides only passive protection and is inferior because it allows **contaminated exudates** to pool within the abdomen, increasing the risk of residual infection.- It necessitates multiple, often painful, changes and does not effectively prevent **fascial retraction**, making subsequent closure more challenging than with VAC.*Prefer closure after laparotomy*- Immediate closure in the context of **severe diffuse contamination** is contraindicated due to an unacceptably high risk of septic complications and residual **intraperitoneal infection**.- Primary closure may also lead to **Abdominal Compartment Syndrome (ACS)** due to significant bowel and peritoneal edema, which has high associated morbidity and mortality.*Antibiotic soaked gauze*- Local application of **antibiotic-soaked gauze** lacks scientific support and does not replace effective systemic antibiotic therapy combined with adequate drainage.- Like NS gauze, it is unable to create a controlled environment for fluid removal or prevent **fascial domain loss**, making definitive closure difficult.

Question 1

All of the following are true about pulp space infection EXCEPT?

Accepted Answer

It is a painless condition

Answer

It is also called as felon

Answer

It may lead to necrosis of finger pulp

Answer

It is infection of small compartments in the pulp formed by vertical septa

Question 2

What is the primary treatment for clostridial myonecrosis?

Accepted Answer

Penicillin

Answer

Amikacin

Answer

Ampicillin

Answer

Gentamicin

Question 3

What is the best treatment for gas gangrene?

Accepted Answer

Debridement with IV penicillin

Answer

Surgical debridement

Answer

Debridement with tetanus toxin

Answer

Debridement with polyvalent antitoxin

Question 4

Which statement regarding antibiotic prophylaxis is true?

Accepted Answer

Antibiotic prophylaxis is indicated for colorectal surgery.

Answer

Antibiotic prophylaxis is not indicated for clean-contaminated surgery.

Answer

Antibiotic prophylaxis is not indicated for gastric ulcer surgery.

Answer

Local irrigation with antibiotics is contraindicated when systemic antibiotics are given.

Question 5

What is the required treatment for acute lymphangitis?

Accepted Answer

Antibiotics and rest

Answer

Immediate lymphangiography

Answer

Immediate multiple incisions

Answer

No special treatment

Question 6

Which one of the following surgical procedures is considered to have a clean-contaminated wound?

Accepted Answer

Elective open cholecystectomy for cholelithiasis

Answer

Herniorrhaphy with mesh repair

Answer

Appendectomy without evidence of inflammation

Answer

Appendectomy with walled off abscess

Question 7

Tetanus is usually noticed in which type of cases?

Accepted Answer

Wounds contaminated with faecal matter

Answer

Burn cases

Answer

Open fractures

Answer

Gunshot wounds

Question 8

Periosteal reaction in a case of acute osteomyelitis can be seen earliest at:

Accepted Answer

10 days

Answer

5 days

Answer

15 days

Answer

20 days

Question 9

A patient with diffuse severely contaminated peritonitis underwent laparotomy and was left open after surgery. Which of the following might help?

Accepted Answer

VAC

Answer

Prefer closure after laparotomy

Answer

Normal saline soaked gauze

Answer

Antibiotic soaked gauze

Question 10

A soldier has suffered shrapnel injuries. Crepitus is noted in the arm. All of the following statements regarding this condition are true except?

Accepted Answer

Clostridium oedematiens is the most common organism responsible for this condition

Answer

Radiograph may show gas in muscle or underlying skin

Answer

Renal failure and liver failure can be possible complications

Answer

Hydrogen sulphide is formed

Surgical Infections — MCQs

Surgical Infections — MCQs

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