Bloodstream Infections and Sepsis — MCQs
Refractory Septic shock is defined as?
Following pathogenetic mechanisms operate in septic shock except -
A patient in the ICU with a central venous catheter (CVC) develops an infection. Microscopy reveals ovoid budding yeast cells. What is the most likely organism?
Which of the following is not a diagnostic criterion for SIRS?
Which of the following is not the component of qSOFA?
Septic shock is primarily due to
True statement about burn resuscitation is
Multiple intrahepatic bile duct dilations with bile lakes and concurrent sepsis are suggestive of.
The most common cause of death due to burns in the early period is?
Late deaths in burns is due to
Bloodstream Infections and Sepsis Indian Medical PG Practice Questions and MCQs
Question 1: Refractory Septic shock is defined as?
- A. Shock requiring mechanical ventilation and inotropic support
- B. Shock with lactate levels >4 mmol/L despite treatment
- C. Shock that does not respond to initial fluid bolus within 1 hour
- D. Shock persisting despite adequate fluid resuscitation and vasopressor support (Correct Answer)
Explanation: ***Shock persisting despite adequate fluid resuscitation and vasopressor support*** - This is the **standard definition** of refractory septic shock according to current **Surviving Sepsis Campaign Guidelines** and critical care literature. - It specifically refers to the failure of **both fluid resuscitation and vasopressor therapy** to restore adequate mean arterial pressure and tissue perfusion. *Shock that does not respond to initial fluid bolus within 1 hour* - This describes **early non-response** to fluid therapy, which is concerning but not the complete definition of refractory shock. - Refractory shock requires failure of **comprehensive standard therapy** (fluids AND vasopressors), not just initial fluid bolus failure. *Shock requiring mechanical ventilation and inotropic support* - This describes a patient in **severe septic shock** with multi-organ support but does not define its **refractory nature**. - The need for these interventions indicates **organ dysfunction** and severity, not necessarily refractoriness to standard resuscitation efforts. *Shock with lactate levels >4 mmol/L despite treatment* - **Elevated lactate** indicates tissue hypoperfusion and ongoing shock, but it is a **severity marker**, not the definition of refractoriness. - High lactate levels can occur even in shock that is **responsive to standard therapy** and doesn't specifically indicate failure of resuscitation efforts.
Question 2: Following pathogenetic mechanisms operate in septic shock except -
- A. Direct toxic endothelial injury
- B. Veno constriction
- C. Increased peripheral vascular resistance (Correct Answer)
- D. Activation of complement
Explanation: Following pathogenetic mechanisms operate in septic shock except - ***Increased peripheral vascular resistance*** - Septic shock is characterized by profound **vasodilation** and a subsequent **decrease in systemic vascular resistance (SVR)**, leading to hypoperfusion. - The body's compensatory mechanisms attempt to increase cardiac output rather than constrict peripheral vessels, making increased PVR an unlikely finding in established septic shock. [1] *Direct toxic endothelial injury* - **Bacterial products** (e.g., endotoxins from Gram-negative bacteria) and inflammatory mediators directly damage the **endothelium**, leading to capillary leak and microvascular dysfunction. - This endothelial damage contributes significantly to the widespread organ damage seen in sepsis. *Veno constriction* - While initial compensatory mechanisms might involve elements of vasoconstriction to maintain blood pressure, the hallmark of septic shock is widespread **vasodilation**, which includes both arterial and venous beds. - Early, fleeting venoconstriction is overshadowed by the profound venodilation and loss of venous tone that ultimately contributes to reduced preload and distributive shock. *Activation of complement* - The innate immune response in sepsis triggers the **complement cascade**, leading to the generation of potent inflammatory mediators. - Complement activation contributes to endothelial damage, leukocyte recruitment, and further amplification of the systemic inflammatory response.
Question 3: A patient in the ICU with a central venous catheter (CVC) develops an infection. Microscopy reveals ovoid budding yeast cells. What is the most likely organism?
- A. Candida (Correct Answer)
- B. Staphylococcus epidermidis
- C. Escherichia coli
- D. Staphylococcus aureus
Explanation: ***Candida*** - **Gram-positive ovoid budding organisms** are characteristic findings for yeast, with **Candida** species being the most common cause of CVC-related fungal infections in ICU patients. - Patients with CVCs are at high risk for candidemia due to compromised skin barriers and often receiving broad-spectrum antibiotics, which can disrupt the normal flora. *Staphylococcus epidermidis* - This is a **Gram-positive coccus** that grows in clusters and is a common cause of CVC-related **bacterial infections**, developing **biofilms** on catheters. - It does not present as an ovoid budding organism on microscopy. *Escherichia coli* - This is a **Gram-negative rod**, typically associated with **urinary tract infections** and sepsis from an abdominal source. - It would not appear as a Gram-positive ovoid budding organism and is not a common cause of primary CVC-related bloodstream infections unless there's an associated abdominal source. *Staphylococcus aureus* - This is a **Gram-positive coccus** that grows in grape-like clusters and can cause severe CVC-related bloodstream infections, often leading to **endocarditis** or widespread dissemination. - Like *S. epidermidis*, it is a bacterium and does not exhibit ovoid budding.
Question 4: Which of the following is not a diagnostic criterion for SIRS?
- A. Hypotension (Correct Answer)
- B. Tachypnoea
- C. Leucocytosis
- D. Tachycardia
Explanation: ### Hypotension - **Hypotension** is a criterion for **sepsis** and **septic shock**, but not for **SIRS** itself. - **SIRS** criteria are based on inflammatory responses, while hypotension indicates a more severe systemic compromise. *Tachycardia* - **Tachycardia**, defined as a **heart rate >90 beats per minute**, is a diagnostic criterion for **SIRS** [1]. - It reflects the body's physiological stress response to a systemic inflammatory state [1]. *Tachypnoea* - **Tachypnoea**, indicated by a **respiratory rate >20 breaths per minute** or a **PaCO2 <32 mmHg**, is a diagnostic criterion for **SIRS** [1]. - This symptom shows the body's effort to compensate for metabolic acidosis or increased oxygen demand. *Leucocytosis* - **Leucocytosis**, defined as a **white blood cell count >12,000/mm³** or **<4,000/mm³**, or the presence of **>10% immature neutrophils (bands)**, is a diagnostic criterion for **SIRS** [1]. - This indicates a significant systemic inflammatory response in the blood [1].
Question 5: Which of the following is not the component of qSOFA?
- A. Respiratory rate >22/min
- B. Altered mental status
- C. Unequally dilated pupils (Correct Answer)
- D. Systolic BP<100 mmHg
Explanation: ***Unequally dilated pupils*** - **Unequally dilated pupils** are not a component of the **qSOFA** score. This finding can be indicative of neurological issues such as increased **intracranial pressure** or **uncal herniation**, but not directly part of the sepsis screening tool [1]. - The qSOFA score focuses on easily obtainable clinical signs to rapidly identify patients at risk for poor outcomes from **sepsis**. *Respiratory rate >22/min* - A **respiratory rate greater than 22 breaths per minute** is one of the three criteria for the **qSOFA** score, indicating significant physiological stress. - This elevated respiratory rate suggests an increased work of breathing, often due to **metabolic acidosis** or **systemic inflammation** associated with sepsis. *Altered mental status* - **Altered mental status** (e.g., Glasgow Coma Scale score less than 15) is a core component of the **qSOFA** score [1]. - This sign reflects **cerebral hypoperfusion** or **encephalopathy** due to the systemic effects of sepsis [1]. *Systolic BP<100 mmHg* - A **systolic blood pressure less than 100 mmHg** is another key criterion of the **qSOFA** score. - This indicates **hypotension** and suggests inadequate tissue perfusion, a critical sign of **circulatory dysfunction** in sepsis [1].
Question 6: Septic shock is primarily due to
- A. Protein
- B. Lipopolysaccharide (Correct Answer)
- C. Peptidoglycan
- D. Teichoic acid
Explanation: ***Lipopolysaccharide*** - **Lipopolysaccharide (LPS)**, an endotoxin found in the outer membrane of **Gram-negative bacteria**, is the primary mediator of **septic shock**. - LPS binding to immune cells triggers a massive release of **pro-inflammatory cytokines**, leading to systemic inflammation, vasodilation, and organ dysfunction characteristic of septic shock. *Protein* - While some bacterial proteins can be **virulence factors**, they are not the primary cause of overwhelming systemic inflammation seen in **septic shock**. - Proteins are the building blocks of all cells and have diverse functions, but they don't exclusively trigger the septic shock cascade in the same way as LPS. *Peptidoglycan* - **Peptidoglycan** is a major component of the bacterial cell wall found in both **Gram-positive** and **Gram-negative bacteria**. - It can stimulate an immune response, but its role in triggering the full cascade of **septic shock** is less pronounced and less direct compared to LPS from Gram-negative bacteria. *Teichoic acid* - **Teichoic acids** are cell wall components specific to **Gram-positive bacteria**. - They can elicit an inflammatory response, but they are generally less potent in inducing the severe, life-threatening systemic effects associated with **septic shock** compared to LPS.
Question 7: True statement about burn resuscitation is
- A. Colloid preferred in the first 24 hours
- B. Half of the calculated fluid is given in the first eight hours (Correct Answer)
- C. Antibiotics should be given more importance over fluid therapy
- D. Diuretics should be given to the patient
Explanation: **Half of the calculated fluid is given in the first eight hours** - The Parkland formula (4 mL/kg/%TBSA burned) is widely used for burn resuscitation, with **half of the total calculated 24-hour fluid volume administered during the first 8 hours** post-burn. - The remaining half of the fluid is then given over the subsequent 16 hours to maintain adequate tissue perfusion and vital organ function. *Colloid preferred in the first 24 hours* - In the initial 24 hours of burn resuscitation, **crystalloid solutions (e.g., Lactated Ringer's)** are generally preferred due to increased capillary permeability, which can lead to colloids leaking into the extravascular space and exacerbating edema. - **Colloids are typically introduced after the first 24 hours** when capillary integrity begins to recover, helping to maintain intravascular volume more effectively. *Antibiotics should be given more importance over fluid therapy* - **Fluid resuscitation is the primary and most critical intervention in the initial management of severe burns** to prevent burn shock and organ dysfunction. - While antibiotics are important later for preventing and treating infections, **fluid therapy takes immediate precedence** in stabilizing the patient and ensuring adequate perfusion. *Diuretics should be given to the patient* - **Diuretics are generally contraindicated in the initial phase of burn resuscitation**, as they can exacerbate hypovolemia and further compromise renal perfusion, leading to acute kidney injury. - The goal is to restore and maintain adequate fluid volume, not to promote fluid loss, unless there is a specific indication for conditions like fluid overload that occurs much later.
Question 8: Multiple intrahepatic bile duct dilations with bile lakes and concurrent sepsis are suggestive of.
- A. Caroli disease (Correct Answer)
- B. Watson-Algali syndrome
- C. Primary sclerosing cholangitis
- D. Klatskin tumor
Explanation: ***Caroli disease*** - **Caroli disease** is characterized by **congenital dilation** of the large intrahepatic bile ducts, leading to bile stasis, stone formation, and recurrent bouts of cholangitis and sepsis [1]. - The presence of **multiple intrahepatic bile duct dilations** and **bile lakes** with concurrent **sepsis** is highly indicative of this condition [1]. *Watson-Algali syndrome* - This is an incorrect term; there is no recognized medical condition by this name associated with bile duct anomalies. - The symptoms described do not correspond to any known genetic or acquired liver disease under this designation. *Primary sclerosing cholangitis* - **Primary sclerosing cholangitis (PSC)** involves **fibrosing inflammation** of both intrahepatic and extrahepatic bile ducts, leading to strictures and dilations, but typically progresses to **cirrhosis** and does not primarily manifest with large "bile lakes" [1]. - While PSC can cause recurrent cholangitis and present with bile duct irregularities, the specific description of "bile lakes" and diffuse dilations better fits Caroli disease [1]. *Klatskin tumor* - A **Klatskin tumor** is a **cholangiocarcinoma** located at the bifurcation of the common hepatic duct, causing **proximal bile duct obstruction** and dilation. - While it can lead to cholangitis and sepsis due to obstruction, it is a localized neoplastic mass, not a congenital diffuse dilation with "bile lakes" throughout the intrahepatic system.
Question 9: The most common cause of death due to burns in the early period is?
- A. Hypovolemic shock (Correct Answer)
- B. Sepsis
- C. Combination of causes
- D. Not applicable
Explanation: ***Hypovolemic shock*** - In the **early period** (first 24-48 hours to first week) following a severe burn, the most common cause of death is **hypovolemic shock**. - Extensive burns cause massive **capillary leak** and fluid shifts from the intravascular space into the interstitial space, leading to severe hypovolemia. - Despite advances in fluid resuscitation protocols (Parkland formula), hypovolemic shock remains the leading cause of early mortality if not promptly and adequately treated. - **Acute renal failure** secondary to hypovolemia is also a major concern in this period. *Sepsis* - Sepsis becomes the predominant cause of death in the **late period** (after the first week post-burn). - Once the skin barrier is destroyed, bacterial colonization occurs, but systemic sepsis typically manifests after several days. - In modern burn care with early excision and grafting plus antibiotics, sepsis risk is managed but remains the leading late complication. *Combination of causes* - While multiple factors can contribute to burn mortality, the question asks for the **most common** specific cause in the early period. - This option is too vague and does not identify the primary pathophysiological mechanism. *Not applicable* - This is incorrect as there are well-established causes of death in burn patients. - Burn mortality follows a predictable temporal pattern with identifiable leading causes in each phase.
Question 10: Late deaths in burns is due to
- A. Contractures
- B. Hypovolemia
- C. Sepsis (Correct Answer)
- D. Neurogenic
Explanation: ***Sepsis*** - **Sepsis** is the leading cause of death in burn patients surviving beyond 48 hours, due to the loss of skin barrier function and subsequent infection. - Large burn wounds create an ideal environment for bacterial invasion and systemic inflammatory response, leading to **multi-organ dysfunction**. *Contractures* - **Contractures** are a long-term complication of burns, causing functional impairment rather than direct mortality. - While they can significantly impact quality of life, they are not a primary cause of **late death**. *Hypovolemia* - **Hypovolemia** is a major cause of early death in burn patients, typically occurring within the first 24-48 hours post-burn. - It results from massive fluid shifts and plasma loss from the burn wound, not from later complications. *Neurogenic* - **Neurogenic shock** or complications are not directly associated with burn fatalities, although severe burns can be associated with pain and psychological trauma. - Death in burns is overwhelmingly related to fluid loss, infection, and subsequent organ failure.
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