A 38-year-old man with no known allergies is brought to the Emergency Department 25 minutes after eating shellfish at a restaurant. He developed generalized urticaria, lip swelling, and wheeze. On examination, he has widespread erythema, facial angioedema, and bilateral expiratory wheeze. His blood pressure is 88/54 mmHg, heart rate 124 bpm, respiratory rate 28 breaths/minute, and oxygen saturation 92% on room air. What is the underlying immunological mechanism responsible for his presentation?
Q52
A 46-year-old woman collapses at a bus stop. Paramedics arrive within 5 minutes and find her unresponsive with no palpable pulse. The cardiac monitor shows ventricular fibrillation. After successful defibrillation and return of spontaneous circulation, she is transferred to the Emergency Department. Her ECG shows ST-segment elevation in leads V1-V4. What underlying mechanism best explains the relationship between her cardiac arrest and ECG findings?
Q53
A 52-year-old man with known type 2 diabetes presents to the Emergency Department with a 48-hour history of productive cough, fever, and increasing shortness of breath. His observations are: temperature 38.9°C, heart rate 118 bpm, blood pressure 98/62 mmHg, respiratory rate 26 breaths/minute, oxygen saturation 91% on room air. Blood tests show: white cell count 18.2 × 10⁹/L, lactate 3.2 mmol/L. A chest X-ray confirms right lower lobe consolidation. What is the pathophysiological basis for the hypotension in septic shock?
Q54
A 64-year-old woman presents to the Emergency Department with a 4-hour history of central chest pain. She has a history of hypertension and hyperlipidaemia. Her observations show: blood pressure 145/88 mmHg, heart rate 92 bpm, respiratory rate 18 breaths/minute, oxygen saturation 97% on room air, and temperature 36.8°C. Her ECG shows sinus rhythm with T-wave inversion in leads V1-V4. Which biochemical marker is most specific for diagnosing acute myocardial infarction?
Q55
A 71-year-old woman with rheumatoid arthritis on methotrexate and prednisolone presents with a 36-hour history of fever and productive cough. Temperature is 38.7°C, blood pressure is 96/62 mmHg, heart rate is 108 bpm, respiratory rate is 26/min, oxygen saturation is 90% on room air. Blood tests show: WBC 3.2 × 10⁹/L, neutrophils 1.8 × 10⁹/L, CRP 198 mg/L, lactate 2.8 mmol/L. Chest X-ray shows right lower lobe consolidation. Which antibiotic regimen is most appropriate as initial empirical therapy?
Q56
A 58-year-old man with no previous cardiac history presents with 30 minutes of crushing central chest pain. His ECG shows 2 mm ST-depression in leads I, aVL, and V2-V5, with 1 mm ST-elevation in leads III and aVR. Blood pressure is 92/58 mmHg, heart rate is 98 bpm. High-sensitivity troponin is significantly elevated at 2,850 ng/L (normal <14 ng/L). What does the ECG pattern suggest and what is the most appropriate management?
Q57
A 29-year-old pregnant woman at 32 weeks gestation presents with sudden-onset severe chest pain and dyspnoea. She is tachypnoeic with respiratory rate 28/min, oxygen saturation 89% on room air, heart rate 118 bpm, blood pressure 102/68 mmHg. She has unilateral left leg swelling. What is the most appropriate immediate diagnostic investigation?
Q58
A 34-year-old woman collapses at home. Her partner calls 999 and attempts CPR. Paramedics arrive and find her in ventricular fibrillation. She receives three shocks and achieves return of spontaneous circulation. On arrival to the Emergency Department, she is intubated and ventilated. Her Glasgow Coma Scale score is 3. Temperature is 36.8°C, blood pressure is 108/65 mmHg on noradrenaline, and ECG shows sinus rhythm with no ST-segment elevation. What is the most appropriate next management step?
Q59
A 52-year-old man is admitted with suspected sepsis secondary to cellulitis of his right leg. He receives 2 litres of IV crystalloid over 1 hour and IV antibiotics. His blood pressure remains 84/50 mmHg and lactate is 4.8 mmol/L. Noradrenaline infusion is commenced. After 2 hours, his blood pressure is 94/58 mmHg on noradrenaline 0.4 mcg/kg/min, heart rate is 115 bpm, and repeat lactate is 5.2 mmol/L. Central venous oxygen saturation (ScvO₂) is measured at 62%. What is the most appropriate next step?
Q60
A 41-year-old woman is brought to the Emergency Department after collapsing at a gym during high-intensity exercise. She regained consciousness quickly but complains of palpitations. Examination reveals a jerky carotid pulse and an ejection systolic murmur that decreases with squatting. ECG shows left ventricular hypertrophy and deep T-wave inversion in the lateral leads. Her father died suddenly aged 38 years. What is the most appropriate immediate investigation?
Acute Medical Presentations UK Medical PG Practice Questions and MCQs
Question 51: A 38-year-old man with no known allergies is brought to the Emergency Department 25 minutes after eating shellfish at a restaurant. He developed generalized urticaria, lip swelling, and wheeze. On examination, he has widespread erythema, facial angioedema, and bilateral expiratory wheeze. His blood pressure is 88/54 mmHg, heart rate 124 bpm, respiratory rate 28 breaths/minute, and oxygen saturation 92% on room air. What is the underlying immunological mechanism responsible for his presentation?
A. Type I hypersensitivity reaction mediated by IgE antibodies causing mast cell degranulation (Correct Answer)
B. Type II hypersensitivity reaction with antibody-mediated cytotoxicity
C. Type III hypersensitivity reaction involving immune complex deposition
D. Type IV hypersensitivity reaction with T-cell mediated delayed response
E. Non-immunological histamine release from direct mast cell activation
Explanation: ***Type I hypersensitivity reaction mediated by IgE antibodies causing mast cell degranulation***
- This patient's presentation with acute generalized **urticaria**, **angioedema**, **wheeze**, and **hypotension** after shellfish ingestion is classic for **anaphylaxis**, which is a rapid **Type I hypersensitivity** reaction.
- It is triggered by the binding of an allergen to **IgE antibodies** on the surface of **mast cells**, leading to their degranulation and release of potent mediators like **histamine** and leukotrienes.
*Type II hypersensitivity reaction with antibody-mediated cytotoxicity*
- This type involves **IgG** or **IgM** antibodies binding to antigens on cell surfaces, leading to cell destruction through **complement activation** or antibody-dependent cellular cytotoxicity.
- Conditions like **autoimmune hemolytic anemia** or drug-induced cytotoxic reactions are examples, which do not manifest as acute widespread urticaria and systemic shock.
*Type III hypersensitivity reaction involving immune complex deposition*
- This reaction occurs when **antigen-antibody complexes** form and deposit in tissues, activating complement and causing inflammation (e.g., **serum sickness**, Arthus reaction).
- Clinical manifestations typically have a **delayed onset** (hours to days) and do not involve the rapid, multisystem collapse seen in anaphylaxis.
*Type IV hypersensitivity reaction with T-cell mediated delayed response*
- This is a **cell-mediated** response driven by **T-lymphocytes**, rather than antibodies, and is characterized by a **delayed onset** (24-72 hours) after antigen exposure.
- Examples include **contact dermatitis** and the tuberculin skin test, which are distinct from the immediate, IgE-mediated reactions seen in anaphylaxis.
*Non-immunological histamine release from direct mast cell activation*
- While this can clinically mimic anaphylaxis (sometimes called an **anaphylactoid reaction**), it involves direct activation of **mast cells** or basophils without prior **IgE sensitization**.
- Given the patient's acute reaction to a known allergen (shellfish) with systemic signs, **IgE-mediated** Type I hypersensitivity is the specific immunological mechanism, differentiating it from a non-immunological direct release.
Question 52: A 46-year-old woman collapses at a bus stop. Paramedics arrive within 5 minutes and find her unresponsive with no palpable pulse. The cardiac monitor shows ventricular fibrillation. After successful defibrillation and return of spontaneous circulation, she is transferred to the Emergency Department. Her ECG shows ST-segment elevation in leads V1-V4. What underlying mechanism best explains the relationship between her cardiac arrest and ECG findings?
A. Acute occlusion of the left anterior descending artery causing myocardial ischaemia and electrical instability (Correct Answer)
B. Chronic cardiomyopathy with progressive ventricular dilatation
C. Hyperkalaemia-induced membrane depolarization leading to arrhythmia
D. Pulmonary embolism causing right ventricular strain
E. Long QT syndrome with torsades de pointes degenerating to ventricular fibrillation
Explanation: ***Acute occlusion of the left anterior descending artery causing myocardial ischaemia and electrical instability***
- The presence of **ST-segment elevation** in leads **V1-V4** (anterior leads) confirms an acute occlusion of the **Left Anterior Descending (LAD)** artery.
- **Acute myocardial ischaemia** disrupts the membrane potential of cardiomyocytes, creating an environment of **electrical instability** that frequently triggers **ventricular fibrillation**.
*Chronic cardiomyopathy with progressive ventricular dilatation*
- While chronic dilatation can lead to arrhythmias, it typically causes a **Bundle Branch Block** or non-specific ST-T changes rather than localized **ST-segment elevation**.
- This mechanism involves **re-entry circuits** from structural scarring, not the acute vascular occlusion suggested by the ECG.
*Hyperkalaemia-induced membrane depolarization leading to arrhythmia*
- **Hyperkalaemia** typically presents with **tall peaked T-waves**, widened QRS complexes, and loss of P-waves, rather than localized ST-elevation.
- While it can cause cardiac arrest, it would not explain the **territorial distribution** (V1-V4) of these ECG findings.
*Pulmonary embolism causing right ventricular strain*
- **Pulmonary embolism** classically shows a **S1Q3T3 pattern**, right axis deviation, or T-wave inversions in the right precordial leads (V1-V3).
- It does not cause a **ST-elevation myocardial infarction (STEMI)** pattern in the anterior leads.
*Long QT syndrome with torsades de pointes degenerating to ventricular fibrillation*
- **Long QT syndrome** is a channelopathy that leads to **Torsades de Pointes**, which can degenerate into ventricular fibrillation.
- This condition does not cause **ST-segment elevation**; the primary finding would be a prolonged **QTc interval** on the post-resuscitation ECG.
Question 53: A 52-year-old man with known type 2 diabetes presents to the Emergency Department with a 48-hour history of productive cough, fever, and increasing shortness of breath. His observations are: temperature 38.9°C, heart rate 118 bpm, blood pressure 98/62 mmHg, respiratory rate 26 breaths/minute, oxygen saturation 91% on room air. Blood tests show: white cell count 18.2 × 10⁹/L, lactate 3.2 mmol/L. A chest X-ray confirms right lower lobe consolidation. What is the pathophysiological basis for the hypotension in septic shock?
A. Cardiogenic pump failure due to myocardial suppression
B. Hypovolaemia secondary to capillary leak and vasodilation (Correct Answer)
C. Obstructive shock from pulmonary embolism
D. Reduced cardiac output from bradycardia
E. Increased systemic vascular resistance causing afterload mismatch
Explanation: ***Hypovolaemia secondary to capillary leak and vasodilation***
- Septic shock is a form of **distributive shock** where inflammatory mediators cause widespread **arterial vasodilation**, significantly reducing systemic vascular resistance.
- Pro-inflammatory cytokines increase **capillary permeability**, allowing protein-rich fluid to leak into the interstitium, causing **relative hypovolaemia** and hypotension.
*Cardiogenic pump failure due to myocardial suppression*
- While **sepsis-induced myocardial dysfunction** can occur due to cytokines like TNF-alpha, it is typically a secondary factor rather than the primary cause of initial hypotension.
- Most patients in early septic shock actually exhibit a **hyperdynamic state** with an initially increased cardiac output.
*Obstructive shock from pulmonary embolism*
- **Obstructive shock** involves a physical barrier to blood flow, such as a massive **PE** or cardiac tamponade, which is not supported by the clinical finding of lobar pneumonia.
- The patient's symptoms are localized to the **right lower lobe consolidation**, pointing towards a primary infectious/septic etiology.
*Reduced cardiac output from bradycardia*
- The clinical data explicitly shows the patient is **tachycardic** (HR 118 bpm), which is a compensatory response to maintain cardiac output during hypotension.
- **Bradycardia** would be an atypical finding in sepsis and usually suggests an alternative diagnosis or imminent circulatory collapse.
*Increased systemic vascular resistance causing afterload mismatch*
- In septic shock, **systemic vascular resistance (SVR)** is characteristically **decreased**, not increased, due to pathological vasodilation.
- Increased SVR is typical of **hypovolaemic** or **cardiogenic shock**, where the body attempts to maintain blood pressure through vasoconstriction.
Question 54: A 64-year-old woman presents to the Emergency Department with a 4-hour history of central chest pain. She has a history of hypertension and hyperlipidaemia. Her observations show: blood pressure 145/88 mmHg, heart rate 92 bpm, respiratory rate 18 breaths/minute, oxygen saturation 97% on room air, and temperature 36.8°C. Her ECG shows sinus rhythm with T-wave inversion in leads V1-V4. Which biochemical marker is most specific for diagnosing acute myocardial infarction?
A. Lactate dehydrogenase (LDH)
B. Creatine kinase (CK)
C. Creatine kinase-MB (CK-MB)
D. High-sensitivity cardiac troponin (Correct Answer)
E. Myoglobin
Explanation: ***High-sensitivity cardiac troponin***- This is the gold-standard marker for diagnosing **acute myocardial infarction** due to its high **sensitivity and specificity** for cardiac muscle injury.- It remains elevated for several days and is preferred over other markers for detecting even minute levels of **myocardial necrosis**.*Creatine kinase (CK)*- **CK** lacks specificity for cardiac tissue as it is found in high concentrations in **skeletal muscle** and the brain.- Elevations are commonly seen in **rhabdomyolysis**, strenuous exercise, or intramuscular injections, making it unreliable for MI diagnosis.*Creatine kinase-MB (CK-MB)*- While more specific than total CK, **CK-MB** is still present in **skeletal muscle** and can be elevated following non-cardiac trauma.- It is primarily used today to detect **re-infarction** because it returns to baseline levels much faster (24-48 hours) than troponin.*Myoglobin*- **Myoglobin** is released very early (within 1-2 hours) after muscle injury, but it is highly **non-specific** as it is found in all muscle types.- Its main clinical utility is its **negative predictive value** in the early hours; if it is not elevated, an MI is less likely, but its presence does not confirm one.*Lactate dehydrogenase (LDH)*- **LDH** is a very late marker of tissue damage and is found in many organs including the **liver, red blood cells, and lungs**.- Due to its poor specificity and the availability of rapid troponin assays, it is effectively **obsolete** in the modern diagnostic workup of chest pain.
Question 55: A 71-year-old woman with rheumatoid arthritis on methotrexate and prednisolone presents with a 36-hour history of fever and productive cough. Temperature is 38.7°C, blood pressure is 96/62 mmHg, heart rate is 108 bpm, respiratory rate is 26/min, oxygen saturation is 90% on room air. Blood tests show: WBC 3.2 × 10⁹/L, neutrophils 1.8 × 10⁹/L, CRP 198 mg/L, lactate 2.8 mmol/L. Chest X-ray shows right lower lobe consolidation. Which antibiotic regimen is most appropriate as initial empirical therapy?
A. Meropenem and linezolid
B. Amoxicillin and metronidazole
C. Co-amoxiclav and clarithromycin
D. Piperacillin-tazobactam, gentamicin, and clarithromycin (Correct Answer)
E. Ceftriaxone and doxycycline
Explanation: ***Piperacillin-tazobactam, gentamicin, and clarithromycin*** - The patient presents with **severe community-acquired pneumonia (CAP)** and **sepsis** in the context of **immunosuppression** (methotrexate and prednisolone) and relative **neutropenia**, necessitating broad-spectrum coverage. - This regimen provides empirical cover for **Gram-negative bacilli** (including **Pseudomonas aeruginosa**), Gram-positive organisms, and **atypical pathogens** via clarithromycin. *Meropenem and linezolid* - While broad, this combination is typically reserved for cases of confirmed **multidrug-resistant (MDR)** organisms or specific risk factors for **MRSA**, which are not indicated as the first step here. - Using **carbapenems** and **linezolid** as initial empirical therapy for standard severe CAP in this setting may lead to unnecessary **antibiotic resistance**. *Amoxicillin and metronidazole* - This regimen is insufficient for severe CAP as it lacks coverage for **Staphylococcus aureus**, **Gram-negative aerobes**, and **atypical bacteria**. - **Metronidazole** is primarily used for **anaerobic infections** (e.g., aspiration pneumonia), which does not align with the primary presentation of acute consolidation and sepsis. *Co-amoxiclav and clarithromycin* - This is the standard treatment for **severe CAP** in immunocompetent patients; however, it lacks adequate coverage against **Pseudomonas**, which is a risk in **immunosuppressed** patients. - The presence of **neutropenia** and high-dose immunosuppression requires the broader antipseudomonal spectrum offered by piperacillin-tazobactam. *Ceftriaxone and doxycycline* - **Ceftriaxone** provides good coverage for most CAP pathogens but lacks activity against **Pseudomonas aeruginosa**, which is a critical consideration in this patient. - While **doxycycline** handles atypicals, the overall regimen is not aggressive enough for a patient with **sepsis**, **hypoxia**, and **immunosuppression**.
Question 56: A 58-year-old man with no previous cardiac history presents with 30 minutes of crushing central chest pain. His ECG shows 2 mm ST-depression in leads I, aVL, and V2-V5, with 1 mm ST-elevation in leads III and aVR. Blood pressure is 92/58 mmHg, heart rate is 98 bpm. High-sensitivity troponin is significantly elevated at 2,850 ng/L (normal <14 ng/L). What does the ECG pattern suggest and what is the most appropriate management?
A. Left main stem or proximal LAD occlusion requiring emergency angiography (Correct Answer)
B. Inferior STEMI requiring primary PCI to right coronary artery
C. NSTEMI with moderate risk suitable for angiography within 72 hours
D. Wellens syndrome indicating critical LAD stenosis requiring urgent angiography
E. Posterior STEMI requiring urgent posterior leads and immediate PCI
Explanation: ***Left main stem or proximal LAD occlusion requiring emergency angiography***
- The pattern of **widespread ST-depression** (I, aVL, V2-V5) combined with **ST-elevation in aVR** is a high-risk indicator of **left main stem occlusion** or multivessel disease.
- Given the presence of **hypotension** and significantly elevated **troponin**, this is considered a **STEMI-equivalent** requiring immediate primary PCI or emergency CABG.
*Inferior STEMI requiring primary PCI to right coronary artery*
- **Inferior STEMI** would typically present with **ST-elevation** in leads II, III, and aVF, rather than widespread depression.
- The elevation in lead III here is overshadowed by more significant aVR elevation and global ischemia, pointing to a more proximal/global lesion.
*NSTEMI with moderate risk suitable for angiography within 72 hours*
- While the ST-depression mirrors NSTEMI, the **haemodynamic instability** (systolic BP 92) and aVR elevation upgrade the risk to immediate intervention.
- Waiting 72 hours for a potential **left main occlusion** is inappropriate and carries a high risk of **cardiogenic shock** or death.
*Wellens syndrome indicating critical LAD stenosis requiring urgent angiography*
- **Wellens syndrome** is characterized by deep **T-wave inversions** or biphasic T-waves in V2-V3 specifically during pain-free intervals.
- This patient is currently in pain with significant **ST-segment shifts**, indicating acute transmural/global ischemia rather than a pre-infarction state.
*Posterior STEMI requiring urgent posterior leads and immediate PCI*
- **Posterior STEMI** usually presents with **ST-depression in V1–V3** and tall R waves, but it would not typically cause **ST-elevation in aVR**.
- While posterior leads (V7-V9) can confirm posterior involvement, the global distribution and aVR elevation are more indicative of **proximal LAD/LMS** pathology.
Question 57: A 29-year-old pregnant woman at 32 weeks gestation presents with sudden-onset severe chest pain and dyspnoea. She is tachypnoeic with respiratory rate 28/min, oxygen saturation 89% on room air, heart rate 118 bpm, blood pressure 102/68 mmHg. She has unilateral left leg swelling. What is the most appropriate immediate diagnostic investigation?
A. CT pulmonary angiography (Correct Answer)
B. Ventilation-perfusion (V/Q) scan
C. D-dimer assay
D. Lower limb Doppler ultrasound
E. Chest X-ray followed by clinical decision rule
Explanation: ***CT pulmonary angiography***
- This patient has a high clinical probability of **pulmonary embolism (PE)** based on severe dyspnoea, hypoxia, and evidence of **DVT (unilateral leg swelling)**; CTPA is the gold standard for definitive diagnosis.
- While radiation is a concern, the **fetal radiation dose** in CTPA is extremely low (<0.1 mGy), making it a safe and preferred choice for maternal survival in acute presentations.
*Ventilation-perfusion (V/Q) scan*
- V/Q scanning is an alternative but often results in **non-diagnostic/indeterminate** results if the patient has any pre-existing pulmonary pathology or an abnormal chest X-ray.
- It carries a slightly higher **fetal radiation dose** than CTPA, although it delivers a lower dose to maternal **breast tissue**.
*D-dimer assay*
- D-dimer levels are **physiologically elevated** during pregnancy, particularly in the third trimester, leading to a very high rate of **false positives**.
- A positive result would not be helpful for diagnosis, and a negative result is insufficient to rule out PE when the **clinical suspicion** is this high.
*Lower limb Doppler ultrasound*
- While a positive Doppler for **DVT** would justify anticoagulation, a negative scan cannot exclude a **pulmonary embolism** if the clot has already embolized.
- In a patient with significant **respiratory distress** and hypoxia, immediate pulmonary imaging is prioritized over limb studies to confirm the life-threatening diagnosis.
*Chest X-ray followed by clinical decision rule*
- A **Chest X-ray** is performed to rule out other causes (like pneumonia or pneumothorax) but is not a definitive **diagnostic tool** for PE.
- Standard clinical decision rules like the **Wells Score** are not fully validated for use in pregnancy, and delaying imaging in an unstable/hypoxic patient is inappropriate.
Question 58: A 34-year-old woman collapses at home. Her partner calls 999 and attempts CPR. Paramedics arrive and find her in ventricular fibrillation. She receives three shocks and achieves return of spontaneous circulation. On arrival to the Emergency Department, she is intubated and ventilated. Her Glasgow Coma Scale score is 3. Temperature is 36.8°C, blood pressure is 108/65 mmHg on noradrenaline, and ECG shows sinus rhythm with no ST-segment elevation. What is the most appropriate next management step?
A. Targeted temperature management to 32-36°C for 24 hours (Correct Answer)
B. Emergency coronary angiography within 2 hours
C. CT head scan to exclude intracranial haemorrhage
D. Commence therapeutic hypothermia to 28°C for neuroprotection
E. Perform immediate transthoracic echocardiography
Explanation: ***Targeted temperature management to 32-36°C for 24 hours***- **Targeted temperature management (TTM)** is indicated for adults who remain unresponsive after **Return of Spontaneous Circulation (ROSC)** following cardiac arrest to improve neurological outcomes.- Current guidelines recommend maintaining a constant temperature between **32°C and 36°C** for at least **24 hours**, followed by controlled rewarming to prevent secondary brain injury.*Emergency coronary angiography within 2 hours*- Immediate angiography is primarily indicated post-ROSC if the **ECG shows ST-segment elevation (STEMI)** or there is high suspicion of an acute coronary cause with hemodynamic instability.- In the absence of **ST-elevation**, stabilizing the patient and initiating **neuroprotective care** takes precedence over emergency catheterization.*CT head scan to exclude intracranial haemorrhage*- A **CT head** may be indicated if a primary neurological event (like **subarachnoid hemorrhage**) is suspected as the cause of arrest, but it is not the immediate priority for neuroprotection.- While a **GCS of 3** is concerning, it is an expected finding in the immediate post-arrest phase and should not delay the initiation of **TTM**.*Commence therapeutic hypothermia to 28°C for neuroprotection*- **Extreme hypothermia** (28°C) is not clinically recommended as it increases the risk of severe complications like **arrhythmias**, coagulopathy, and infection.- Evidence suggests that moderate targets (**32-36°C**) provides the best balance of **neuroprotection** and safety.*Perform immediate transthoracic echocardiography*- **Echocardiography** is a useful tool to assess wall motion and cardiac function, but it should be performed as part of the secondary assessment after stabilization.- Initial priority must be given to the **post-cardiac arrest bundle**, including airway management and **targeted temperature control**.
Question 59: A 52-year-old man is admitted with suspected sepsis secondary to cellulitis of his right leg. He receives 2 litres of IV crystalloid over 1 hour and IV antibiotics. His blood pressure remains 84/50 mmHg and lactate is 4.8 mmol/L. Noradrenaline infusion is commenced. After 2 hours, his blood pressure is 94/58 mmHg on noradrenaline 0.4 mcg/kg/min, heart rate is 115 bpm, and repeat lactate is 5.2 mmol/L. Central venous oxygen saturation (ScvO₂) is measured at 62%. What is the most appropriate next step?
A. Perform transthoracic echocardiography to assess cardiac function (Correct Answer)
B. Increase noradrenaline dose to achieve MAP ≥65 mmHg
C. Administer further IV fluid bolus of 500 mL
D. Add vasopressin as second vasopressor agent
E. Commence IV hydrocortisone 50 mg 6-hourly
Explanation: ***Perform transthoracic echocardiography to assess cardiac function***- This patient has **refractory septic shock** with persistent hypotension, rising **lactate**, and a low **central venous oxygen saturation (ScvO₂ < 70%)**, indicating inadequate tissue oxygen delivery and potentially low **cardiac output**.- **Echocardiography** is crucial to evaluate for **sepsis-induced myocardial dysfunction** (which is common) or to reassess for persistent fluid responsiveness, which will guide targeted therapy with inotropes or further judicious fluids.*Increase noradrenaline dose to achieve MAP ≥65 mmHg*- While the **Mean Arterial Pressure (MAP)** target is not yet met, simply escalating **noradrenaline** without assessing cardiac function can increase **afterload** on an already compromised heart, potentially worsening tissue perfusion despite a higher MAP.- The low **ScvO₂** points to a primary issue with **oxygen delivery** (often due to low cardiac output) rather than purely vasodilation, which higher vasopressor doses alone won't fix.*Administer further IV fluid bolus of 500 mL*- The patient has already received **2 litres of crystalloid**, and without reassessing **fluid responsiveness**, further empirical fluid boluses risk **fluid overload** and associated complications like **pulmonary edema**, which can impair oxygenation.- With persistent shock and rising lactate, a more targeted assessment of **volume status** and cardiac function via echocardiography is needed before administering more fluids.*Add vasopressin as second vasopressor agent*- **Vasopressin** is a second-line vasopressor for refractory vasodilation in septic shock, but it is primarily a **vasoconstrictor** and does not directly address **cardiac contractility** or **cardiac output**.- Given the low **ScvO₂**, the primary concern is insufficient oxygen delivery, which may stem from **myocardial dysfunction**, and vasopressin alone would not correct this.*Commence IV hydrocortisone 50 mg 6-hourly*- **Corticosteroids** like **hydrocortisone** are generally considered in septic shock when patients remain hemodynamically unstable despite adequate fluid resuscitation and high-dose vasopressor support (e.g., noradrenaline >0.25 mcg/kg/min).- While the patient's noradrenaline dose is significant, the immediate priority with a low **ScvO₂** is to diagnose the specific hemodynamic derangement (e.g., pump failure) to guide more precise interventions rather than broadly suppressing inflammation.
Question 60: A 41-year-old woman is brought to the Emergency Department after collapsing at a gym during high-intensity exercise. She regained consciousness quickly but complains of palpitations. Examination reveals a jerky carotid pulse and an ejection systolic murmur that decreases with squatting. ECG shows left ventricular hypertrophy and deep T-wave inversion in the lateral leads. Her father died suddenly aged 38 years. What is the most appropriate immediate investigation?
A. Transthoracic echocardiography (Correct Answer)
B. Coronary angiography
C. Cardiac MRI
D. Exercise tolerance test
E. 24-hour Holter monitor
Explanation: ***Transthoracic echocardiography***
- The patient's presentation, including exercise-induced syncope, jerky carotid pulse, an ejection systolic murmur decreasing with squatting (indicating dynamic left ventricular outflow tract obstruction), ECG with **LVH** and deep T-wave inversion, and a family history of sudden cardiac death, strongly points to **Hypertrophic Cardiomyopathy (HCM)**.
- **Transthoracic echocardiography (TTE)** is the **gold standard immediate investigation** for HCM, as it directly visualizes **asymmetric septal hypertrophy** and can detect **systolic anterior motion (SAM)** of the mitral valve, confirming the diagnosis at the bedside.
*Coronary angiography*
- While chest pain and syncope can suggest coronary artery disease, the specific clinical findings, such as a **jerky pulse** and a **dynamic murmur** that changes with preload (squatting), are not typical for primary ischemic heart disease.
- **Coronary angiography** is an invasive procedure primarily used to assess **coronary artery stenosis** and is not the initial diagnostic test for suspected structural heart diseases like HCM in this context.
*Cardiac MRI*
- **Cardiac MRI** offers superior detailed imaging of myocardial structure, including precise measurements of **ventricular hypertrophy** and detection of **myocardial fibrosis** (late gadolinium enhancement), which is valuable for risk stratification in HCM.
- However, it is generally less available than TTE, more time-consuming, and thus not the **most immediate** or first-line investigation in an acute emergency setting for initial diagnosis.
*Exercise tolerance test*
- An **exercise tolerance test** is generally **contraindicated** in patients with symptomatic, suspected HCM due to the high risk of inducing **ventricular arrhythmias** and **sudden cardiac death**, especially with dynamic left ventricular outflow tract obstruction.
- This test is primarily used for assessing functional capacity and prognostic risk in stable, often asymptomatic, HCM patients under controlled conditions.
*24-hour Holter monitor*
- A **24-hour Holter monitor** is crucial for detecting and quantifying arrhythmias, particularly **non-sustained ventricular tachycardia (NSVT)**, which is a major risk factor for sudden cardiac death in HCM.
- While important for overall risk stratification and management of HCM, it does not provide the **immediate structural diagnosis** of the cardiomyopathy itself, which is essential as a first step after acute collapse.
