Shock Syndromes and Management — MCQs
What is the treatment for class I hypovolemic shock?
Which of the following ions is important in irreversible cell injury?
All are true about septic shock in children except which of the following?
The following are true of Mendelson's syndrome –
12 yr old Child admitted to ICU with blunt trauma and femur fracture - PaO2 60% despite 100% O2 and rebreather mask, CXR shows lung fields clear but the patient remains confused. What is most likely the diagnosis?
Refractory Septic shock is defined as?
A 50 kg patient has 40 % burn of the body surface area. Calculate the ringer lactate solution to be given for first 8 hours of fluid:
Which of the following bacteria is the most likely cause of toxic shock syndrome?
Which of the following is a superantigen?
Fever stops and rash begins is diagnostic of-
Shock Syndromes and Management Indian Medical PG Practice Questions and MCQs
Question 1: What is the treatment for class I hypovolemic shock?
- A. IV fluids alone
- B. Admission and IV fluids
- C. Blood transfusion
- D. Oral liquids (Correct Answer)
Explanation: ***Oral liquids*** - **Class I hemorrhagic shock** involves a **minimal blood loss** (up to 15%) with usually no significant changes in vital signs. - In most cases, patients are **hemodynamically stable** and can compensate for the fluid loss by drinking oral liquids. *IV fluids alone* - While IV fluids are suitable for **more severe classes of shock**, they are generally **not necessary for class I**, where oral rehydration is sufficient. - This option does not reflect the least invasive and appropriate treatment for the mildest form of hypovolemia. *Admission and IV fluids* - **Admission** to a hospital is usually reserved for patients with more severe symptoms or those requiring close monitoring for significant fluid loss [1]. - **IV fluids** are **not typically required** for class I shock as oral intake is preferred [1]. *Blood transfusion* - **Blood transfusions** are indicated in cases of **severe hemorrhage** (typically class III or IV) where there is a substantial loss of red blood cell mass. - It is **never the first-line treatment for class I shock** due to the minimal blood loss and associated risks.
Question 2: Which of the following ions is important in irreversible cell injury?
- A. Sodium
- B. Chloride
- C. Calcium (Correct Answer)
- D. Potassium
Explanation: ***Calcium*** - An increase in intracellular **calcium** concentration is a critical event in irreversible cell injury, activating various destructive enzymes like **phospholipases**, **proteases**, **endonucleases**, and ATPases [1]. - This influx of calcium can occur due to mitochondrial dysfunction (leading to impaired calcium sequestration) or damage to the plasma membrane [1]. *Sodium* - While important for maintaining **osmotic balance** and cell volume, dysregulation of sodium primarily contributes to **cellular swelling** (hydropic change), which is an early and often reversible sign of cell injury [1]. - Increased intracellular sodium typically leads to water influx, but its direct role in irreversible damage is secondary to calcium. *Chloride* - Changes in chloride ion distribution are often secondary to sodium dysregulation and play a role in maintaining **charge neutrality** and osmotic balance across the cell membrane. - It is not directly implicated as a primary mediator of the **enzyme activation cascade** that leads to irreversible cell damage. *Potassium* - **Potassium** is the major intracellular cation; its leakage out of the cell is a consequence of cell membrane damage, indicating loss of membrane integrity. - While significant **potassium efflux** is a sign of severe injury, it is not the initiator of the irreversible damage pathway, unlike calcium. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Cellular Responses to Stress and Toxic Insults: Adaptation, Injury, and Death, pp. 57-62.
Question 3: All are true about septic shock in children except which of the following?
- A. Tachycardia is common during the early phase.
- B. Decreased peripheral vascular resistance is observed.
- C. The first response is a decrease in cardiac output due to vasodilation.
- D. Hypotension is a late sign of septic shock. (Correct Answer)
Explanation: ***Hypotension is a late sign of septic shock.*** - In children, the body's compensatory mechanisms, particularly increased heart rate and systemic vascular resistance, effectively maintain **blood pressure** despite poor perfusion. - **Hypotension** usually indicates decompensation and is a grave sign in pediatric septic shock. *Tachycardia is common during the early phase.* - **Tachycardia** is a primary compensatory mechanism in early septic shock to maintain **cardiac output** in the face of decreased systemic vascular resistance. - It is often the *first and most reliable sign* of shock in children. *Decreased peripheral vascular resistance is observed.* - The inflammatory response in sepsis causes widespread **vasodilation**, leading to a significant **decrease in systemic vascular resistance (SVR)**. - This reduced resistance is a hallmark of distributive shock, which characterizes septic shock. *The first response is a decrease in cardiac output due to vashodilation.* - While vasodilation does occur, the initial response to maintain perfusion often involves an **increase in cardiac output** through compensatory **tachycardia** and improved contractility. - A *decrease in cardiac output* due to vasodilation is not typically the very first response, as the body attempts to compensate vigorously.
Question 4: The following are true of Mendelson's syndrome –
- A. Steroids have been shown to improve outcome
- B. Critical volume of aspirate is 50 mls
- C. Critical pH of gastric aspirate is 1.5
- D. Onset of symptoms generally occurs within 30 minutes (Correct Answer)
Explanation: ***Onset of symptoms generally occurs within 30 minutes*** - Mendelson's syndrome refers to **chemical pneumonitis** resulting from pulmonary aspiration of sterile gastric contents. - Symptoms like **bronchospasm**, **dyspnea**, and **tachycardia** typically manifest rapidly, often within minutes to 30 minutes post-aspiration. *Steroids have been shown to improve outcome* - **Corticosteroids** are generally **not recommended** for the treatment of Mendelson's syndrome or chemical pneumonitis caused by gastric aspiration. - Their use can potentially increase the risk of **secondary bacterial pneumonia** due to immunosuppression, without significant clinical benefit in improving lung injury. *Critical volume of aspirate is 50 mls* - The critical volume of aspirate associated with Mendelson's syndrome is generally considered to be **25 mL** or **0.3 mL/kg** of gastric contents. - Aspiration of volumes greater than this threshold significantly increases the risk of developing **severe pneumonitis**. *Critical pH of gastric aspirate is 1.5* - The critical pH of gastric aspirate associated with Mendelson's syndrome is generally considered to be **less than 2.5**. - A pH below this value indicates highly acidic gastric contents, which cause **severe chemical burns** to the tracheobronchial tree and lung parenchyma.
Question 5: 12 yr old Child admitted to ICU with blunt trauma and femur fracture - PaO2 60% despite 100% O2 and rebreather mask, CXR shows lung fields clear but the patient remains confused. What is most likely the diagnosis?
- A. Pulmonary contusion.
- B. Fat embolism syndrome. (Correct Answer)
- C. Hypovolaemic shock.
- D. Pulmonary embolism.
Explanation: ***Fat embolism syndrome*** - The combination of **hypoxemia** unresponsive to oxygen, **confusion**, and a history of **femur fracture** (a long bone fracture) strongly points to **fat embolism syndrome (FES)** [1], [2]. - FES typically presents with the classic triad of **respiratory insufficiency**, **neurological symptoms**, and a **petechial rash** (though the rash may be subtle or delayed) [1]. *Pulmonary contusion* - While possible in blunt trauma, a pulmonary contusion would likely show **infiltrates or opacities on chest X-ray**, which is not the case here ("CXR shows lung fields clear"). - The degree of hypoxemia and confusion is more typical of a systemic process like FES rather than an isolated pulmonary contusion with a clear CXR [2]. *Hypovolemic shock* - Hypovolemic shock would manifest primarily as **tachycardia**, **hypotension**, and signs of poor perfusion, not necessarily severe hypoxemia refractory to oxygen with a clear CXR. - While blunt trauma can cause hypovolemia, the severe hypoxemia and neurological symptoms without clear signs of hemorrhage make FES more likely. *Pulmonary embolism* - A pulmonary embolism (PE) could cause hypoxemia and confusion, but it is less common immediately following a long bone fracture unless there are other predisposing factors. - Furthermore, fat embolism syndrome is a more specific and acute complication in the context of long bone fractures like a femur fracture [1].
Question 6: 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 7: A 50 kg patient has 40 % burn of the body surface area. Calculate the ringer lactate solution to be given for first 8 hours of fluid:
- A. 8 Litres
- B. 2 Litres
- C. 4 Litres (Correct Answer)
- D. 1 Litre
Explanation: ***4 Litres*** - The **Parkland formula** for fluid resuscitation in burn patients is **4 mL x body weight (kg) x % total body surface area (TBSA) burned**. - For this patient: 4 mL x 50 kg x 40% = 8000 mL or **8 Litres** of Ringer's Lactate in the first 24 hours. Half of this volume ([8 Litres / 2] = **4 Litres**) is given in the first 8 hours. *8 Litres* - This amount represents the **total fluid requirement** for the entire first 24 hours, not just the first 8 hours. - Only **half of the total calculated fluid** is administered in the initial 8-hour period. *2 Litres* - This volume is generally **too low** for a patient with 40% TBSA burns, which is considered a significant burn. - Insufficient fluid resuscitation can lead to **burn shock** and organ hypoperfusion. *1 Litre* - This amount is **grossly inadequate** for a patient with 40% TBSA burns. - Administering such a small volume would likely result in **severe hypovolemic shock** and clinical deterioration.
Question 8: Which of the following bacteria is the most likely cause of toxic shock syndrome?
- A. Clostridium perfringens
- B. Streptococcus pyogenes
- C. Neisseria meningitidis
- D. Staphylococcus aureus (Correct Answer)
Explanation: ***Staphylococcus aureus*** - This bacterium is the most common cause of **toxic shock syndrome (TSS)**, particularly in cases associated with **tampon use** or **surgical wound infections**. - It produces **toxic shock syndrome toxin-1 (TSST-1)**, a superantigen that triggers a massive, systemic inflammatory response. *Clostridium perfringens* - This bacterium is primarily associated with **gas gangrene** (clostridial myonecrosis) and **food poisoning**. - Its toxins cause tissue necrosis and gas production, which are not characteristic features of TSS. *Streptococcus pyogenes* - While *S. pyogenes* can cause a form of **toxic shock-like syndrome (STSS)**, it is distinct from TSS caused by *S. aureus*. - *S. pyogenes* is more commonly known for causing **strep throat**, **scarlet fever**, and **necrotizing fasciitis**. *Neisseria meningitidis* - This bacterium is the primary cause of **meningitis** and **meningococcemia**, a severe systemic infection. - It does not produce the specific toxins associated with TSS or STSS, and its clinical presentation is typically different, involving petechial or purpuric rash and signs of central nervous system infection.
Question 9: Which of the following is a superantigen?
- A. Clostridium difficile toxin
- B. Cholera toxin
- C. Exfoliative toxin of Staph. aureus
- D. Staphylococcal toxic shock syndrome toxin (Correct Answer)
Explanation: ***Staphylococcal toxic shock syndrome toxin*** - The **Staphylococcal toxic shock syndrome toxin (TSST-1)** is a classic example of a **superantigen**. - **TSST-1** binds directly to the MHC class II molecules on antigen-presenting cells and the Vβ region of T-cell receptors, leading to massive, non-specific T-cell activation and a cytokine storm. - Other staphylococcal superantigens include enterotoxins and exfoliative toxins. *Clostridium difficile toxin* - *Clostridium difficile* produces **toxins A and B**, which are **enterotoxins** and **cytotoxins**, respectively, leading to pseudomembranous colitis. - These toxins primarily target intestinal epithelial cells, causing inflammation and fluid secretion, and do not act as superantigens. *Cholera toxin* - **Cholera toxin** is an **AB5 exotoxin** produced by *Vibrio cholerae*, which activates adenylate cyclase in intestinal cells. - This leads to increased cAMP levels, excessive fluid and electrolyte secretion, and severe watery diarrhea, but it does not function as a superantigen. *Exfoliative toxin of Staph. aureus* - **Exfoliative toxins (ETA and ETB)** produced by *Staphylococcus aureus* cause staphylococcal scalded skin syndrome (SSSS). - While these toxins can act as superantigens, they are primarily proteases that cleave desmoglein-1 in the epidermis. - In this question, TSST-1 is the more characteristic and well-established superantigen among the options listed.
Question 10: Fever stops and rash begins is diagnostic of-
- A. Fifth disease
- B. Toxic shock syndrome
- C. Measles
- D. Roseola infantum (Correct Answer)
Explanation: ***Roseola infantum*** - This condition is characterized by a **high fever** that typically lasts for 3-5 days, followed by its abrupt resolution and the subsequent appearance of a **maculopapular rash**. - The rash usually starts on the **trunk** and spreads outward, often appearing just as the child's fever breaks, a key diagnostic feature. *Fifth disease* - Characterized by a distinctive **"slapped cheek" rash** on the face, followed by a lacy rash on the trunk and extremities. - The rash typically appears after mild prodromal symptoms, but the onset of rash is not directly linked to the resolution of a high fever. *Toxic shock syndrome* - This severe illness is marked by a **sudden high fever**, diffuse **erythematous rash**, hypotension, and multi-organ involvement. - The fever and rash typically occur concurrently, and the rash does not appear after the fever breaks. *Measles* - Measles is characterized by a prodromal phase of **fever**, cough, coryza, and conjunctivitis, followed by the appearance of **Koplik spots**. - The characteristic **maculopapular rash** typically appears 3-5 days after the onset of fever, while the fever is still present or peaking, not after its resolution.
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