Necrotizing Fasciitis — MCQs
Extensive surgical debridement, decompression or amputation may be indicated in the following clinical setting except
Pathognomonic sign of traumatic fracture is
Which of the following best describes the transmission pattern of necrotizing ulcerative gingivitis?
Drugs of choice for MRSA in skin and soft tissue infections are:
Causative organism for ANUG is:
Which type of necrosis is most commonly associated with the spread of infection?
Acute orchitis is characterized by all of the following except:
A 6-year-old boy presents with fever and chills, cough, rapid breathing, difficulty breathing, and chest pain. A culture from a respiratory sample shows Gram-positive bacteria. What is the most likely organism causing this infection?
A long-term diabetic patient with blisters walked barefoot for a few miles on hot sand. He presented with rapidly spreading deep tissue infection with extensive tissue necrosis. What is the most probable diagnosis?
An elderly male patient presented with a sudden onset of scrotal pain and discharge as shown in the image. What is the likely diagnosis?
Necrotizing Fasciitis Indian Medical PG Practice Questions and MCQs
Question 1: Extensive surgical debridement, decompression or amputation may be indicated in the following clinical setting except
- A. Acute rhabdomyolysis
- B. Acute haemolytic streptococcal cellulitis
- C. Acute thrombophlebitis (Correct Answer)
- D. Progressive synergistic gangrene
Explanation: ***Acute thrombophlebitis*** - This condition involves inflammation and **thrombosis** of a superficial vein, typically managed with **anticoagulation**, pain relief, and local measures. - Surgical intervention like debridement, decompression, or amputation is generally **not indicated** unless there are severe complications such as infection or extensive tissue necrosis, which are rare. *Acute rhabdomyolysis* - Severe rhabdomyolysis can lead to **compartment syndrome**, necessitating fasciotomy (decompression) to prevent irreversible muscle and nerve damage. - In cases of extensive muscle necrosis, **surgical debridement** may be required to remove non-viable tissue and prevent further systemic complications. *Acute haemolytic streptococcal cellulitis* - While initial management is antibiotics, rapidly progressing necrotizing infections (like **necrotizing fasciitis**, a severe form often caused by *Streptococcus pyogenes*) require **extensive surgical debridement** to remove dead tissue and control the spread of infection. - Delayed debridement can lead to systemic toxicity, limb loss, or death, making aggressive surgical intervention crucial. *Progressive synergistic gangrene* - Also known as **Meleney's gangrene**, this rare but severe soft tissue infection requires aggressive and **extensive surgical debridement** of all necrotic tissue. - The combination of aerobic and anaerobic bacteria creates a progressive, destructive lesion that can necessitate amputation if not adequately controlled by debridement.
Question 2: Pathognomonic sign of traumatic fracture is
- A. Tenderness
- B. Redness
- C. Crepitus (Correct Answer)
- D. Swelling
Explanation: - ***Crepitus*** - Crepitus, the **grating or crunching sound** or sensation produced by the friction of bone fragments, is the most specific and **pathognomonic sign** of a fracture. - It occurs when the rough surfaces of bone ends rub against each other due to movement. - *Tenderness* - While **tenderness** is a common sign of a fracture, it is not pathognomonic, as it can occur with many other injuries, such as sprains or contusions. - **Localized pain** upon palpation is a general indicator of injury but lacks specificity for bone fracture. - *Redness* - **Redness (erythema)** is a sign of inflammation and can be present in various injuries or infections but is not typically a direct indicator of a traumatic fracture unless accompanied by significant soft tissue damage or infection. - It is a non-specific sign and doesn't confirm bone disruption. - *Swelling* - **Swelling (edema)** commonly accompanies fractures due to hematoma formation and inflammation but is also a general response to many types of injury and is not unique to fractures. - It indicates tissue damage but does not specifically differentiate a fracture from a sprain or severe contusion.
Question 3: Which of the following best describes the transmission pattern of necrotizing ulcerative gingivitis?
- A. Transmissible through direct contact with low communicability
- B. Transmissible only through specific contact routes (Correct Answer)
- C. Highly communicable through multiple routes
- D. Non-transmissible between individuals
Explanation: ***Transmissible only through specific contact routes*** - While not highly contagious, **necrotizing ulcerative gingivitis (NUG)** can be transmitted through direct contact involving saliva or exudates, especially under conditions favoring bacterial overgrowth. - This typically occurs in close personal contact, such as **kissing** or sharing utensils, but only if the recipient has predisposing factors for NUG development. *Transmissible through direct contact with low communicability* - This option is partially correct but doesn't fully capture "only through specific contact routes," implying a broader direct contact that isn't always the case for NUG. - NUG's transmission is more nuanced, relying on concurrent **risk factors** in the recipient for the disease to manifest. *Highly communicable through multiple routes* - NUG is **not highly communicable** and does not spread easily through various routes like airborne or casual contact. - Its development is strongly linked to specific **oral microbiome shifts** and host factors, not widespread transmission. *Non-transmissible between individuals* - While NUG is not considered a classic contagious disease in the same way as viral infections, a small risk of transmission through **direct saliva contact** does exist. - This statement incorrectly implies no possibility of interpersonal spread, despite the presence of causative bacteria in affected individuals' oral fluids.
Question 4: Drugs of choice for MRSA in skin and soft tissue infections are:
- A. Clindamycin, Vancomycin
- B. Vancomycin, Linezolid (Correct Answer)
- C. Vancomycin, Teicoplanin
- D. Dicloxacillin, Vancomycin
Explanation: ***Vancomycin, Linezolid*** - **Vancomycin** is a cornerstone for treating **MRSA** infections, particularly severe ones, due to its efficacy against resistant staphylococci. - **Linezolid** is an alternative for **MRSA** infections, especially in cases of vancomycin resistance or intolerance, and offers good oral bioavailability. *Clindamycin, Vancomycin* - While **vancomycin** is correct, **clindamycin** has varying efficacy against **MRSA** and high rates of inducible resistance, making it less reliable as a primary drug of choice. - Clindamycin's use for MRSA often requires initial susceptibility testing, including a **D-test**, to rule out inducible clindamycin resistance. *Vancomycin, Teicoplanin* - **Vancomycin** is a primary **MRSA** drug, but **teicoplanin** is largely used in Europe and is structurally similar to vancomycin, often reserved for cases where vancomycin is not tolerated or preferred. - While effective, **teicoplanin** is not as universally recognized as a first-line option alongside vancomycin in all regions. *Dicloxacillin, Vancomycin* - **Vancomycin** is appropriate, but **dicloxacillin** is an **anti-staphylococcal penicillin** and is not effective against **MRSA** (Methicillin-Resistant Staphylococcus aureus) because MRSA, by definition, is resistant to all beta-lactam antibiotics. - Dicloxacillin is mainly used for **MSSA** (Methicillin-Sensitive Staphylococcus aureus) infections.
Question 5: Causative organism for ANUG is:
- A. Streptococcus sanguis
- B. Treponema pallidum and spirochetes
- C. Fusospirochetal complex (Correct Answer)
- D. Staphylococcus epidermidis
Explanation: ***Fusospirochetal complex*** - **Acute Necrotizing Ulcerative Gingivitis (ANUG)**, also known as Vincent's angina or trench mouth, is caused by a synergistic polymicrobial infection involving **Fusobacterium species** (particularly F. nucleatum) and **oral spirochetes** (Borrelia vincentii and Treponema species). - This fusospirochetal complex creates a destructive, ulcerative inflammation of the gingiva, presenting with **painful, bleeding gums, punched-out papillae, pseudomembrane formation**, and characteristic **fetid breath**. - The condition typically occurs in patients with **poor oral hygiene, stress, immunosuppression**, or **malnutrition**. *Streptococcus sanguis* - This bacterium is a common commensal of the oral cavity and plays a role in **dental plaque formation** and initial colonization of tooth surfaces. - While present in the mouth, it is **not the causative agent** for the necrotizing lesions characteristic of ANUG. *Treponema pallidum and spirochetes* - **Treponema pallidum** specifically causes **syphilis**, a sexually transmitted infection, not ANUG. - While **oral spirochetes** (other Treponema and Borrelia species) are indeed critical components of ANUG, they work synergistically with **Fusobacterium**, hence the term "fusospirochetal complex." - This option is partially correct but incomplete and includes T. pallidum which is incorrect. *Staphylococcus epidermidis* - **Staphylococcus epidermidis** is a skin commensal organism implicated in **nosocomial infections** and biofilm formation on medical devices. - It has **no role** in the pathogenesis of ANUG.
Question 6: Which type of necrosis is most commonly associated with the spread of infection?
- A. Fibrinoid necrosis
- B. Fat necrosis
- C. Liquefactive necrosis (Correct Answer)
- D. Coagulative necrosis
Explanation: ***Liquifactive necrosis*** - Caused by the enzymatic digestion of tissue, leading to the formation of liquid pus, typically associated with bacterial infections [1]. - Commonly occurs in the **brain** and in a tissue impacted by **pyogenic bacteria** [1], demonstrating how infection can lead to tissue damage. *Fat necrosis* - Primarily related to inflammation of fat tissue, often seen in pancreatitis or trauma to fat areas. - It is not directly caused by infections but rather by fat cell damage and necrosis, leading to **saponification**. *Fibrinoid necrosis* - Associated with **immune-mediated vascular injury**, seen in conditions like **vasculitis** or **malignant hypertension** [2]. - Characterized by the deposition of **fibrin-like protein** [2], not directly related to infectious processes. *Coagulative necrosis* - Typically occurs in ischemic conditions like myocardial infarction, where tissue architecture is preserved despite cell death. - It is not directly linked to infection spread, as it relates more to loss of blood supply rather than infectious agents. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 193-194. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 103-104.
Question 7: Acute orchitis is characterized by all of the following except:
- A. Increased local temperature
- B. Erythematous scrotum
- C. Decreased blood flow (Correct Answer)
- D. Raised TLC
Explanation: ***Decreased blood flow*** - **Acute orchitis** is an inflammatory process that typically leads to increased blood flow (hyperemia) to the affected testis due to the inflammatory response. - Decreased blood flow would be more characteristic of conditions like **testicular torsion**, which is an emergent condition causing ischemia. *Increased local temperature* - **Inflammation** is characterized by the classic signs of rubor (redness) and calor (heat), leading to an **increased local temperature** in the affected area. - This is a common finding in acute orchitis due to the inflammatory response. *Erythematous scrotum* - The inflammatory process in orchitis causes **vasodilation** and increased vascular permeability, leading to redness and swelling of the overlying scrotal skin. - An **erythematous scrotum** is a typical clinical sign of acute orchitis. *Raised TLC* - **TLC (Total Leukocyte Count)** is often elevated in cases of acute infection or inflammation, such as orchitis. - A **raised TLC** indicates a systemic inflammatory response to the infection.
Question 8: A 6-year-old boy presents with fever and chills, cough, rapid breathing, difficulty breathing, and chest pain. A culture from a respiratory sample shows Gram-positive bacteria. What is the most likely organism causing this infection?
- A. Streptococcus pyogenes
- B. Streptococcus pneumoniae (Correct Answer)
- C. Staphylococcus aureus
- D. Propionibacterium acnes
Explanation: ***Streptococcus pneumoniae*** - This clinical picture describes typical symptoms of **pneumonia** in a child, including fever, cough, rapid and difficult breathing, and chest pain. - **_Streptococcus pneumoniae_** is the most common bacterial cause of community-acquired pneumonia in children. The respiratory sample showing gram-positive bacteria further supports this. *Staphylococcus aureus* - While **_Staphylococcus aureus_** can cause pneumonia, it is less common than _Streptococcus pneumoniae_ in community-acquired cases in healthy children and often associated with more severe, necrotizing forms or post-viral infections. - While it is a **Gram-positive bacterium**, its clinical presentation would not be the most likely first choice for typical pneumonia symptoms in this age group. *Propionibacterium acnes* - **_Propionibacterium acnes_** (now *Cutibacterium acnes*) is primarily associated with **acne vulgaris** and, less commonly, opportunistic infections related to implanted devices or some rare soft tissue infections. - It is not a typical cause of primary respiratory infections like pneumonia. *Streptococcus pyogenes* - **_Streptococcus pyogenes_** (Group A Streptococcus) is known for causing **pharyngitis** (strep throat), skin infections (impetigo, cellulitis), and scarlet fever. - While it can rarely cause pneumonia, it is not a common cause, and the constellation of symptoms points more strongly to _Streptococcus pneumoniae_.
Question 9: A long-term diabetic patient with blisters walked barefoot for a few miles on hot sand. He presented with rapidly spreading deep tissue infection with extensive tissue necrosis. What is the most probable diagnosis?
- A. Burn
- B. Cellulitis
- C. Diabetic foot
- D. Necrotizing fasciitis (Correct Answer)
Explanation: ***Necrotizing fasciitis*** - The rapid spread of deep tissue infection with extensive necrosis, especially in an immunocompromised patient like a diabetic, is highly characteristic of **necrotizing fasciitis**. [1] - **Diabetic peripheral neuropathy** can lead to unnoticed injury (walking barefoot on hot sand) and impaired wound healing, further predisposing to severe infections. [2] *Burn* - While walking on hot sand can cause burns, this patient's presentation of "rapidly spreading deep tissue infection" and "extensive tissue necrosis" goes beyond a typical burn injury, suggesting an overwhelming infection. - Burns primarily involve direct tissue damage from heat, whereas the described pathology is indicative of a **bacterial infection** escalating rapidly. *Cellulitis* - **Cellulitis** is a superficial skin infection that typically presents as localized redness, warmth, and swelling, but it usually does not involve deep tissue necrosis or such rapid, extensive spread. - It lacks the hallmark sign of rapid progression to **necrosis** and involvement of deep fascial planes that necessitate urgent surgical debridement. *Diabetic foot* - **Diabetic foot** is a broad term encompassing various foot complications in diabetes, including ulcers, infections, and Charcot arthropathy. While this patient has a diabetic foot, the specific presentation of **rapidly spreading infection** with **extensive necrosis** points to a particular, severe diagnosis within the diabetic foot spectrum, rather than the general term. [2] - The context describes a specific acute, life-threatening infectious process rather than the chronic complications typically associated with the general term "diabetic foot."
Question 10: An elderly male patient presented with a sudden onset of scrotal pain and discharge as shown in the image. What is the likely diagnosis?
- A. Fournier’s gangrene (Correct Answer)
- B. Torsion of testis
- C. Scrotal carcinoma
- D. Acute epididymo-orchitis
Explanation: ***Fournier's gangrene*** - The sudden onset of scrotal pain with discharge in an elderly male, combined with **tissue necrosis** and extensive scrotal skin changes, is characteristic of **Fournier's gangrene** (necrotizing fasciitis of the genitalia). - Elderly males are at higher risk due to **diabetes**, **immunocompromise**, and **urogenital infections**, making this a rapidly progressive and potentially life-threatening condition requiring urgent surgical debridement. *Acute epididymo-orchitis* - While epididymo-orchitis can cause scrotal pain and discharge, it typically does **not cause tissue necrosis** or the extensive scrotal skin changes described. - It presents as **localized inflammation** of the epididymis/testis without the widespread necrotizing changes seen in this case. *Torsion of testis* - Testicular torsion typically presents with **abrupt, severe scrotal pain** and swelling, but usually **without discharge** or the extensive scrotal skin changes seen here. - It constitutes a **surgical emergency** due to compromised blood supply to the testis, but doesn't involve necrotizing infection. *Scrotal carcinoma* - Scrotal carcinoma usually presents as a **painless mass or ulceration** that grows over time, rather than a sudden onset of severe pain and discharge. - It represents a **chronic process** and doesn't typically cause the acute necrotizing inflammatory changes observed in this case.
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