Surgical Infections Practice Questions

Q: Which one of the following statements is NOT correct regarding Necrotising Soft Tissue infections?

They are monomicrobial in nature. ***They are monomicrobial in nature*** - Necrotizing soft tissue infections (NSTIs) are predominantly **polymicrobial**, involving a mix of aerobic and anaerobic bacteria. - While some cases can be monomicrobial (e.g., due to *Streptococcus pyogenes* or *Clostridium perfringens*), the statement that they *are* monomicrobial is generally false. *Treatment consists of wide local excision and appropriate antibiotics* - This statement is **correct**. **Aggressive surgical debridement** (wide local excision) to remove all necrotic tissue is the cornerstone of treatment for NSTIs. - **Broad-spectrum antibiotics** are also essential to cover the polymicrobial nature of these infections, but they are insufficient without surgical intervention. *Tissue biopsy is required for culture and diagnosis* - This statement is **correct**. While the diagnosis is primarily clinical, **tissue biopsy** for gram stain, culture, and histopathology is crucial for identifying the causative organisms and guiding definitive antibiotic therapy. - This helps differentiate NSTIs from other severe soft tissue infections and improves treatment accuracy. *Crepitus, skin blistering and focal skin gangrene are typical presenting features* - This statement is **correct**. These are classic signs of advanced necrotizing soft tissue infections. - **Crepitus** indicates gas production by bacteria, **skin blistering** (bullae) suggests dermal involvement, and **focal skin gangrene** is a direct sign of tissue necrosis, all pointing to the severity and rapid progression of NSTIs.

Q: A 62-year-old female had a kidney stone and was treated with PCNL. After 2 days, she comes to the OPD with chills and fever. What is the complication?

Bacterial sepsis. ***Bacterial sepsis*** - **Chills and fever** two days after a **Percutaneous Nephrolithotomy (PCNL)** are highly suggestive of a systemic infection, specifically **bacterial sepsis**, as this procedure carries a risk of introducing bacteria into the bloodstream. - Urinary tract manipulation, especially in a patient with a potentially *infected kidney stone*, can lead to bacteremia and subsequent **sepsis** if not properly managed. *Acute pancreatitis* - **Acute pancreatitis** is not a common complication of PCNL. It typically presents with severe **epigastric pain** radiating to the back, often with nausea and vomiting, and is usually associated with gallstones or alcohol abuse. - While it can cause fever, the clinical presentation and context do not strongly support **pancreatitis** as the primary issue following a PCNL. *Ureteric stricture* - A **ureteric stricture** is a *late complication* of kidney stone treatment and typically leads to symptoms of **urinary obstruction**, such as flank pain, rather than acute fever and chills two days post-procedure. - It would not cause acute systemic signs like **chills and fever** within such a short timeframe after PCNL. *Splenic injury* - **Splenic injury** is a rare but possible complication of procedures around the left kidney; however, it would typically present with **abdominal pain**, signs of **hemorrhage** (e.g., hypotension), and sometimes shoulder pain, not primarily with fever and chills as the immediate post-operative concern. - While fever can occur with internal injuries, the primary and most immediate concern with fever and chills after a urological procedure is **infection**.

Q: Extensive surgical debridement, decompression or amputation may be indicated in the following clinical setting except

Acute thrombophlebitis. ***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.

Q: Preferred time for prophylactic antibiotic administration for surgery?

At the time of induction of anaesthesia. ***At the time of induction of anaesthesia*** - This timing ensures that a **therapeutic concentration** of the antibiotic is present in the tissues at the time of the initial surgical incision, when the risk of bacterial contamination is highest. - Administering the antibiotic too early or too late can reduce its effectiveness in preventing **surgical site infections (SSIs)**. *1 day before surgery* - Administering antibiotics a day before surgery would lead to the drug being **metabolized and eliminated** from the body before the surgical incision is made, rendering it ineffective for prophylaxis. - This timing also increases the risk of **antibiotic resistance** development without providing adequate protection against SSIs. *I.V. during surgery* - Administering the antibiotic intravenously during surgery means that the drug will not have reached sufficient **tissue concentrations** at the crucial moment of the initial incision. - The protective effect is largely dependent on adequate tissue levels **prior to contamination**, which would not be achieved by administration only during the procedure. *I.M. 6 hrs before surgery* - While closer to the optimal timing than 1 day before, administering intramuscularly 6 hours prior may result in **suboptimal drug levels** at the time of incision, especially for drugs with shorter half-lives. - Intramuscular administration can also have variable absorption rates compared to intravenous, potentially delaying peak tissue concentration and reducing reliability for **prophylactic efficacy**.

Q: Cause of Ludwig angina is:

Tooth infection. ***Tooth infection*** - **Odontogenic infections**, particularly from the mandibular molars (especially 2nd and 3rd molars), are the most common cause of Ludwig's angina, accounting for **70-90% of cases**. - These infections spread contiguously from the **apex of the tooth** through the thin lingual cortex into the submandibular and sublingual spaces. - The infection causes **bilateral cellulitis** of the floor of the mouth with characteristic "bull neck" appearance. *Retropharyngeal abscess* - A retropharyngeal abscess forms in the **potential space between the pharynx and prevertebral fascia**. - While it can cause airway compromise and neck swelling, it's anatomically distinct from Ludwig's angina, which involves the **submandibular, sublingual, and submental spaces**. - Retropharyngeal abscess typically presents with dysphagia, neck stiffness, and fever. *Parotid abscess* - A parotid abscess is an infection of the **parotid gland**, located superficially in the preauricular region. - It causes swelling anterior to the ear and along the **mandibular angle**, not the floor of the mouth. - It does not involve the submandibular/sublingual spaces and does not cause the bilateral "board-like" induration characteristic of Ludwig's angina. *Tonsillitis* - While tonsillar infections can occasionally spread to deep neck spaces, they typically cause **peritonsillar abscess** (quinsy). - Tonsillitis rarely causes Ludwig's angina unless there is direct extension through the pharyngeal wall, which is uncommon. - The anatomical distance between the tonsillar fossa and the submandibular space makes this an unlikely cause.

Q: Which of the following is a poor prognostic factor in Pott's paraplegia?

Long-standing paraplegia. ***Long-standing paraplegia*** - **Long-standing paraplegia** indicates prolonged spinal cord compression, leading to irreversible neurological damage due to fibrosis, myelomalacia, and permanent structural changes. - This is associated with poor recovery outcomes even after surgical decompression. - **Sudden/rapid progression** is also a poor prognostic factor, but long-standing duration has consistently worse outcomes in literature. *Motor paralysis alone* - **Motor paralysis without sensory or sphincter involvement** suggests incomplete cord compression affecting primarily the motor tracts. - This is considered a **good prognostic factor** as it indicates less severe and more localized cord damage. - Recovery potential is significantly higher when sensory and autonomic functions are preserved. *Paraplegia in children* - Children have **better neurological recovery potential** compared to adults due to higher neuroplasticity and better capacity for neural regeneration. - Early intervention in pediatric Pott's paraplegia often results in **favorable outcomes**. - This is considered a **good prognostic factor**. *Gradual onset of paraplegia* - **Gradual onset** allows time for medical intervention before irreversible cord damage occurs. - It also allows for compensatory mechanisms and collateral circulation to develop. - This is a **good prognostic factor** compared to acute/sudden onset which indicates rapid cord compression.

Q: Best skin disinfectant for central line insertion is?

Chlorhexidine. ***Chlorhexidine*** - **Chlorhexidine gluconate** with alcohol is highly recommended for **skin antisepsis** prior to central venous catheter insertion due to its rapid and persistent antimicrobial activity. - It effectively reduces the risk of **catheter-related bloodstream infections (CRBSIs)** by targeting a broad spectrum of bacteria. *Povidone iodine* - While effective, **povidone iodine** has a slower onset of action and is less persistent compared to chlorhexidine, making it less ideal for this specific procedure. - Its efficacy can be reduced in the presence of organic material, and it may cause **skin irritation** in some patients. *Cetrimide* - **Cetrimide** is a cationic surfactant with antiseptic properties but is generally considered less potent and less widely recommended than chlorhexidine for surgical skin preparation. - It is more commonly found in preparations for cleaning wounds rather than for **major invasive procedures** like central line insertion. *Alcohol* - **Alcohol** provides rapid antisepsis and has a broad spectrum of activity, but its effect is not persistent and it is volatile, leading to quick evaporation. - Its efficacy is enhanced when combined with other agents, such as chlorhexidine, rather than being used alone for **central line insertion**.

Q: Pre-splenectomy immunization should be given against which of the following organisms:

All of the options. ***All of the options*** - Pre-splenectomy immunization against encapsulated bacteria like *Haemophilus influenzae type b*, *Neisseria meningitidis*, and *Streptococcus pneumoniae* is crucial to prevent **overwhelming post-splenectomy infection (OPSI)**. - Splenic dysfunction or removal impairs the body's ability to clear these organisms, making vaccination a vital prophylactic measure. *Haemophilus influenzae* - This is an **encapsulated bacterium** that causes serious infections like meningitis and epiglottitis, especially in immunocompromised individuals. - While immunization against *H. influenzae* type b is recommended, it is not the sole organism for which immunization is required before splenectomy. *Neisseria meningitides* - This **encapsulated bacterium** causes meningitis and meningococcemia, and individuals with asplenia are highly susceptible to severe, rapidly progressing forms of these infections. - Vaccination for *N. meningitides* is a critical part of pre-splenectomy care but should be done in conjunction with other recommended vaccines. *Streptococcus pneumoniae* - This is a common **encapsulated bacterium** responsible for pneumonia, meningitis, and sepsis, with asplenic patients being at significantly higher risk for severe pneumococcal disease. - *S. pneumoniae* vaccination is essential before splenectomy, but along with others listed, it forms a comprehensive vaccination strategy.

Q: Fibreoptic scopes are sterilized by

Glutaraldehyde. ***Glutaraldehyde*** - **Glutaraldehyde** is the most commonly used agent for **high-level disinfection** of heat-sensitive endoscopes and fibreoptic equipment in clinical practice. - It effectively kills bacteria, viruses, fungi, and most spores through **alkylation** of proteins and nucleic acids. - While technically providing high-level disinfection rather than true sterilization, it is the **standard method** for processing flexible endoscopes between procedures. - **Advantages:** Liquid-based, relatively quick (20-45 minutes), compatible with delicate instruments, and does not require special equipment. *Ethylene oxide* - **Ethylene oxide** (EtO) can achieve true sterilization of heat-sensitive instruments and is sometimes used for rigid endoscopes requiring sterility. - However, it is **not practical for routine flexible endoscope processing** due to: lengthy cycle times (12-24 hours including aeration), need for specialized equipment, toxic residue concerns, and cost. - Glutaraldehyde remains preferred for **routine clinical use** of flexible fibreoptic scopes. *Alcohol* - **Alcohol** (ethanol, isopropanol) is an intermediate-level disinfectant effective against many bacteria and viruses. - It is **not sporicidal** and cannot achieve high-level disinfection or sterilization. - Used only for surface disinfection and preliminary cleaning, not as the primary disinfection method for endoscopes. *Autoclaving* - **Autoclaving** uses high-pressure steam (121°C or 134°C) for sterilization and is highly effective. - **Not suitable for flexible fibreoptic scopes** as the high heat would **damage** the delicate optical fibers, lenses, and plastic components. - May be used for some heat-resistant rigid endoscopic instruments.

Question 1

Which one of the following statements is NOT correct regarding Necrotising Soft Tissue infections?

Accepted Answer

They are monomicrobial in nature

Answer

Treatment consists of wide local excision and appropriate antibiotics

Answer

Tissue biopsy is required for culture and diagnosis

Answer

Crepitus, skin blistering and focal skin gangrene are typical presenting features

Question 2

A 55-year-old diabetic woman develops necrotizing fasciitis of the perineum following a minor gynecologic procedure. She has septic shock, multiorgan failure, and extensive tissue necrosis. Her family requests 'everything be done,' but her prognosis is poor. Evaluate the ethical and medical approach to her care.

Accepted Answer

Extensive debridement with time-limited trial of intensive care

Answer

Transfer to another facility for second opinion

Answer

Limited surgical intervention with family counseling about prognosis

Answer

Palliative care transition with comfort measures only

Question 3

A 62-year-old female had a kidney stone and was treated with PCNL. After 2 days, she comes to the OPD with chills and fever. What is the complication?

Accepted Answer

Bacterial sepsis

Answer

Acute pancreatitis

Answer

Ureteric stricture

Answer

Splenic injury

Question 4

Extensive surgical debridement, decompression or amputation may be indicated in the following clinical setting except

Accepted Answer

Acute thrombophlebitis

Answer

Acute rhabdomyolysis

Answer

Acute haemolytic streptococcal cellulitis

Answer

Progressive synergistic gangrene

Question 5

Preferred time for prophylactic antibiotic administration for surgery?

Accepted Answer

At the time of induction of anaesthesia

Answer

1 day before surgery

Answer

I.V. during surgery

Answer

I.M. 6 hrs before surgery

Question 6

Cause of Ludwig angina is:

Accepted Answer

Tooth infection

Answer

Retropharyngeal abscess

Answer

Parotid abscess

Answer

Tonsillitis

Question 7

Which of the following is a poor prognostic factor in Pott's paraplegia?

Accepted Answer

Long-standing paraplegia

Answer

Paraplegia in children

Answer

Gradual onset of paraplegia

Answer

Motor paralysis alone

Question 8

Best skin disinfectant for central line insertion is?

Accepted Answer

Chlorhexidine

Answer

Povidone iodine

Answer

Cetrimide

Answer

Alcohol

Question 9

Pre-splenectomy immunization should be given against which of the following organisms:

Accepted Answer

All of the options

Answer

Haemophilus influenzae

Answer

Neisseria meningitidis

Answer

Streptococcus pneumoniae

Question 10

Fibreoptic scopes are sterilized by

Accepted Answer

Glutaraldehyde

Answer

Ethylene oxide

Answer

Alcohol

Answer

Autoclaving

Surgical Infections — MCQs

Surgical Infections — MCQs

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