A 76-year-old man with metastatic prostate cancer presents to the Emergency Department with a 72-hour history of worsening confusion, decreased urine output, and lethargy. Temperature is 37.2°C, blood pressure is 102/68 mmHg, heart rate is 98 bpm. Blood tests show: sodium 128 mmol/L, potassium 5.8 mmol/L, urea 18.2 mmol/L, creatinine 245 μmol/L (baseline 110 μmol/L), calcium 3.85 mmol/L (corrected), WBC 9.2 × 10⁹/L. What is the primary underlying cause of this presentation?
Q62
A 59-year-old man with inferior STEMI receives primary PCI. During recovery, he develops sudden-onset severe chest pain. Blood pressure is 88/62 mmHg in the right arm, 142/86 mmHg in the left arm. Heart rate is 108 bpm. Examination reveals new early diastolic murmur at the left sternal edge. ECG shows ST elevation in leads I, aVL, and V1-V6. What is the most likely complication?
Q63
A 33-year-old woman with known nut allergy accidentally consumes a dessert containing almonds. Within 10 minutes, she develops generalized urticaria, lip swelling, wheeze, and feels dizzy. Blood pressure is 88/52 mmHg, heart rate is 124 bpm, oxygen saturation is 92% on room air. Adrenaline 0.5 mg IM is administered immediately. After 5 minutes, her wheeze persists, blood pressure remains 90/54 mmHg, and she remains tachycardic. What is the most appropriate next management step?
Q64
A 45-year-old man collapses at work. Witnesses report he complained of feeling lightheaded and hot before falling forward. He has a 5 cm laceration to his forehead from the fall. On examination, he is alert, blood pressure is 118/72 mmHg, heart rate is 68 bpm and regular, and ECG shows normal sinus rhythm. He has no past medical history. What is the most likely diagnosis?
Q65
A 68-year-old woman presents to the Emergency Department with fever, confusion, and right-sided flank pain. Temperature is 38.9°C, blood pressure is 92/58 mmHg, heart rate is 112 bpm, and respiratory rate is 24 breaths/minute. Blood tests show: WBC 18.2 × 10⁹/L, neutrophils 15.8 × 10⁹/L, lactate 3.1 mmol/L, creatinine 185 μmol/L (baseline 95 μmol/L). What is her qSOFA score and its implication?
Q66
A 62-year-old woman presents with central chest pain radiating to her jaw. Her ECG shows ST-segment depression of 2 mm in leads V3-V6 and positive troponin I. Blood pressure is 145/88 mmHg and heart rate is 72 bpm. She is on aspirin 75 mg daily for previous TIA. Which combination of antiplatelet therapy is most appropriate for initial management according to current guidelines?
Q67
A 54-year-old man with community-acquired pneumonia is being treated for sepsis in the Emergency Department. His blood pressure is 78/45 mmHg despite 30 mL/kg crystalloid fluid resuscitation. Heart rate is 118 bpm and lactate is 5.2 mmol/L. Which pharmacological intervention should be initiated next according to the Surviving Sepsis Campaign guidelines?
Q68
A 49-year-old man with known severe latex allergy presents to the Emergency Department 10 minutes after putting on latex gloves at work. He has facial flushing, generalized urticaria, and reports feeling dizzy. His blood pressure is 92/58 mmHg, heart rate 105 bpm, and oxygen saturation 96% on room air. He has no wheeze. After initial treatment with intramuscular adrenaline, intravenous fluids, and antihistamines, his symptoms resolve. Four hours later he is asymptomatic with stable observations. What is the minimum recommended observation period before discharge for this patient?
Q69
A 41-year-old woman attends the Emergency Department following three episodes of syncope over the past 2 weeks. Each episode was preceded by palpitations and occurred without warning. She has no significant past medical history. Her resting ECG shows sinus rhythm with a short PR interval of 90 milliseconds and a slurred upstroke to the QRS complex. Echocardiography is structurally normal. What is the most likely mechanism of her syncopal episodes?
Q70
A 55-year-old woman with metastatic breast cancer on chemotherapy presents to the Emergency Department with a 12-hour history of fever, rigors, and general malaise. Her temperature is 38.7°C, heart rate 112 bpm, blood pressure 108/64 mmHg, respiratory rate 20/min. Blood tests show white cell count 1.2 × 10⁹/L, neutrophils 0.4 × 10⁹/L, CRP 145 mg/L. She is diagnosed with neutropenic sepsis. Which antibiotic regimen is most appropriate as first-line empirical therapy according to UK guidelines?
Acute Medical Presentations UK Medical PG Practice Questions and MCQs
Question 61: A 76-year-old man with metastatic prostate cancer presents to the Emergency Department with a 72-hour history of worsening confusion, decreased urine output, and lethargy. Temperature is 37.2°C, blood pressure is 102/68 mmHg, heart rate is 98 bpm. Blood tests show: sodium 128 mmol/L, potassium 5.8 mmol/L, urea 18.2 mmol/L, creatinine 245 μmol/L (baseline 110 μmol/L), calcium 3.85 mmol/L (corrected), WBC 9.2 × 10⁹/L. What is the primary underlying cause of this presentation?
A. Urosepsis from urinary tract infection
B. Hypercalcaemia causing acute kidney injury and neurological symptoms (Correct Answer)
C. Syndrome of inappropriate ADH secretion (SIADH)
D. Adrenal insufficiency from metastatic disease
E. Tumour lysis syndrome
Explanation: ***Hypercalcaemia causing acute kidney injury and neurological symptoms***
- The severely elevated **corrected calcium level of 3.85 mmol/L** is the most striking laboratory abnormality and directly explains the **confusion and lethargy**, which are classic neuro-psychiatric manifestations of severe hypercalcaemia.
- High calcium levels cause **nephrogenic diabetes insipidus** and renal vasoconstriction, leading to **volume depletion** and significant **acute kidney injury** (creatinine doubled from baseline), which further contributes to symptoms and the observed **hyperkalaemia** and elevated urea.
*Urosepsis from urinary tract infection*
- The patient is **afebrile** (37.2°C) and has a **normal white blood cell count** (9.2 × 10⁹/L), making an acute systemic infection, such as urosepsis, less likely as the primary cause of this severe presentation.
- While sepsis can cause AKI and confusion, it does not explain the profound **hypercalcaemia** and is not the central underlying cause given the complete clinical picture.
*Syndrome of inappropriate ADH secretion (SIADH)*
- SIADH typically presents with **euvolaemic hyponatraemia** and does not account for the profound **hypercalcaemia**, **hyperkalaemia**, or significant **renal impairment** (elevated urea and creatinine) indicating volume depletion.
- This condition involves fluid retention and often low urine output but would not directly lead to the severe electrolyte and renal derangements observed beyond hyponatraemia.
*Adrenal insufficiency from metastatic disease*
- While adrenal insufficiency can cause **hyponatraemia** (128 mmol/L) and **hyperkalaemia** (5.8 mmol/L), it is typically associated with more pronounced **hypotension** and often **hypoglycaemia**.
- Adrenal insufficiency does not cause severe **hypercalcaemia**, which in this patient with metastatic prostate cancer is highly suggestive of paraneoplastic syndrome or bone metastases.
*Tumour lysis syndrome*
- Tumour lysis syndrome (TLS) is characterized by **hypocalcaemia** (due to phosphate binding), **hyperkalaemia**, **hyperphosphataemia**, and **hyperuricaemia**.
- The patient exhibits severe **hypercalcaemia**, directly contradicting a key diagnostic criterion for TLS, which is often triggered by chemotherapy in high-grade lymphomas or leukemias.
Question 62: A 59-year-old man with inferior STEMI receives primary PCI. During recovery, he develops sudden-onset severe chest pain. Blood pressure is 88/62 mmHg in the right arm, 142/86 mmHg in the left arm. Heart rate is 108 bpm. Examination reveals new early diastolic murmur at the left sternal edge. ECG shows ST elevation in leads I, aVL, and V1-V6. What is the most likely complication?
A. Ventricular septal defect
B. Type A aortic dissection extending to the coronary ostia (Correct Answer)
C. Acute mitral regurgitation from papillary muscle rupture
D. Left ventricular free wall rupture
E. Reinfarction in the LAD territory
Explanation: ***Type A aortic dissection extending to the coronary ostia***- The presence of a **blood pressure differential** greater than 20 mmHg between arms and a new **early diastolic murmur** (aortic regurgitation) is pathognomonic for an ascending aortic dissection.- Extension into the coronary ostia explains the new **ST-segment elevation** (anterolateral) and sudden chest pain post-procedure, indicating a catastrophic surgical emergency.*Ventricular septal defect*- Typically occurs 3–5 days post-MI and presents with a new **harsh holosystolic murmur** at the left lower sternal border, not a diastolic murmur.- It would not cause a **blood pressure discrepancy** between the right and left arms.*Acute mitral regurgitation from papillary muscle rupture*- Usually follows an inferior MI and causes a **holosystolic murmur** radiating to the axilla, often accompanied by acute **pulmonary edema**.- This condition does not explain the **diastolic murmur** of aortic insufficiency or the arm-to-arm blood pressure difference.*Left ventricular free wall rupture*- Presents with sudden **hemodynamic collapse** and signs of **cardiac tamponade**, such as jugular venous distension and muffled heart sounds.- This usually leads to **pulseless electrical activity (PEA)** rather than a specific murmur and blood pressure differential between the limbs.*Reinfarction in the LAD territory*- While this would explain the new **ST elevation** in leads V1-V6, it does not account for the **early diastolic murmur** of aortic regurgitation.- Reinfarction alone cannot cause a significant **blood pressure discrepancy** between the right and left arms.
Question 63: A 33-year-old woman with known nut allergy accidentally consumes a dessert containing almonds. Within 10 minutes, she develops generalized urticaria, lip swelling, wheeze, and feels dizzy. Blood pressure is 88/52 mmHg, heart rate is 124 bpm, oxygen saturation is 92% on room air. Adrenaline 0.5 mg IM is administered immediately. After 5 minutes, her wheeze persists, blood pressure remains 90/54 mmHg, and she remains tachycardic. What is the most appropriate next management step?
A. Administer second dose of IM adrenaline 0.5 mg (Correct Answer)
B. Commence IV adrenaline infusion
C. Give IV hydrocortisone 200 mg and IV chlorphenamine 10 mg only
D. Administer nebulized adrenaline 5 mg
E. Give IV fluid bolus 500 mL and reassess
Explanation: ***Administer second dose of IM adrenaline 0.5 mg***- In the management of **anaphylaxis**, if there is an inadequate response to the first dose of **intramuscular (IM) adrenaline** after 5 minutes, a second dose should be administered immediately.- **IM adrenaline** remains the safest and most effective first-line treatment for reversing life-threatening **respiratory and cardiovascular compromise**.*Commence IV adrenaline infusion*- **Intravenous (IV) adrenaline** is reserved for patients with refractory anaphylaxis who do not respond to multiple **IM doses** and must only be managed by **experienced specialists** (e.g., intensive care or anesthesia).- Rapid IV administration carries a high risk of causing lethal **cardiac arrhythmias** and severe **hypertension** compared to the IM route.*Give IV hydrocortisone 200 mg and IV chlorphenamine 10 mg only*- **Corticosteroids** and **antihistamines** are considered **second-line treatments** and should never delay the administration of adrenaline.- These medications do not treat the **immediate life-threatening** features like hypotension or bronchospasm and are primarily used to prevent **protracted symptoms** or late-phase reactions.*Administer nebulized adrenaline 5 mg*- **Nebulized adrenaline** is specifically indicated for **upper airway obstruction** (stridor) but does not provide the **systemic vasoconstriction** needed to treat hypotension.- It is an adjunct therapy and does not replace the need for **IM adrenaline** in cases of systemic anaphylactic shock.*Give IV fluid bolus 500 mL and reassess*- While **IV fluid resuscitation** is crucial for treating anaphylactic-induced **vasodilation**, it should be performed concurrently with, not instead of, repeated **IM adrenaline** doses.- The primary physiological reversal agent for anaphylaxis is **adrenaline**, which addresses both the underlying **capillary leak** and the **bronchoconstriction**.
Question 64: A 45-year-old man collapses at work. Witnesses report he complained of feeling lightheaded and hot before falling forward. He has a 5 cm laceration to his forehead from the fall. On examination, he is alert, blood pressure is 118/72 mmHg, heart rate is 68 bpm and regular, and ECG shows normal sinus rhythm. He has no past medical history. What is the most likely diagnosis?
A. Vasovagal syncope (Correct Answer)
B. Hypoglycaemia
C. Cardiac arrhythmia
D. Seizure disorder
E. Transient ischaemic attack
Explanation: ***Vasovagal syncope***
- The presence of **prodromal symptoms** such as feeling **lightheaded and hot** before falling is a classic indicator of vasovagal syncope, representing autonomic activation prior to loss of consciousness.
- A **rapid and complete recovery** to an alert state, combined with normal vital signs, a **normal ECG**, and no past medical history, strongly points to a benign reflex-mediated event.
*Hypoglycaemia*
- This typically presents with **prolonged altered mental status**, confusion, or sweating rather than a sudden collapse with rapid recovery.
- Patients usually have a known history of **diabetes** or are on medications that predispose them to low blood glucose levels.
*Cardiac arrhythmia*
- Cardiac syncope often occurs **suddenly without warning** or prodrome and is frequently associated with an **abnormal ECG** or underlying structural heart disease.
- While the injury (laceration) can happen in cardiac events, the specific **pre-syncope symptoms** described and a normal ECG make a primary electrical event less likely.
*Seizure disorder*
- Seizures are generally followed by a **post-ictal period** of confusion, drowsiness, or focal neurological deficits, which this patient does not exhibit.
- Witnesses would typically report **tonic-clonic movements**, tongue biting, or urinary incontinence, rather than a simple fall forward after feeling hot.
*Transient ischaemic attack*
- A TIA involves **focal neurological deficits** (e.g., unilateral weakness, speech disturbance, visual loss) rather than a generalized loss of consciousness or collapse.
- **Loss of consciousness** is an extremely rare presentation for a TIA unless it involves the vertebrobasilar circulation, which would also include symptoms like vertigo or diplopia.
Question 65: A 68-year-old woman presents to the Emergency Department with fever, confusion, and right-sided flank pain. Temperature is 38.9°C, blood pressure is 92/58 mmHg, heart rate is 112 bpm, and respiratory rate is 24 breaths/minute. Blood tests show: WBC 18.2 × 10⁹/L, neutrophils 15.8 × 10⁹/L, lactate 3.1 mmol/L, creatinine 185 μmol/L (baseline 95 μmol/L). What is her qSOFA score and its implication?
A. qSOFA = 2; suggests sepsis with increased mortality risk
B. qSOFA = 1; low risk requiring ward-based management only
C. qSOFA = 3; indicates high risk of mortality and need for ICU assessment (Correct Answer)
D. qSOFA = 2; indicates need for immediate dialysis
E. qSOFA = 3; mandates immediate intubation and mechanical ventilation
Explanation: ***qSOFA = 3; indicates high risk of mortality and need for ICU assessment***- The patient presents with **altered mental status** (confusion), **systolic blood pressure ≤100 mmHg** (92 mmHg), and **respiratory rate ≥22/min** (24 breaths/minute), each contributing 1 point to the qSOFA score, totaling 3.- A **qSOFA score ≥2** signifies a high likelihood of **sepsis** and increased **mortality risk**, necessitating urgent **ICU assessment** and heightened clinical vigilance.*qSOFA = 2; suggests sepsis with increased mortality risk*- This option is incorrect because the patient's clinical presentation clearly meets all three criteria for the **qSOFA score**, making the calculated score 3, not 2.- While a score of 2 does suggest sepsis risk, it **underestimates** the acute severity and immediate management needs indicated by this patient's full clinical picture.*qSOFA = 1; low risk requiring ward-based management only*- This calculation is incorrect as the patient fulfills criteria for **three qSOFA points** (confusion, hypotension, tachypnea), not just one.- A score of 1 would imply a lower risk, but this patient's presentation with significant vital sign derangements and acute kidney injury suggests a much higher level of **risk and urgency** than ward-based management alone could provide.*qSOFA = 2; indicates need for immediate dialysis*- The **qSOFA score** is primarily a rapid screening tool for **sepsis-related mortality risk**, not a direct indication for specific interventions like dialysis.- Although the patient has **acute kidney injury** (creatinine doubled), the qSOFA score is 3, and the decision for **dialysis** depends on the severity of renal failure and associated complications, not solely on qSOFA.*qSOFA = 3; mandates immediate intubation and mechanical ventilation*- While the qSOFA score is indeed 3, indicating a high-risk patient, it does not **mandate immediate intubation** and mechanical ventilation as a primary action.- The decision for **airway management** and mechanical ventilation is based on a comprehensive clinical assessment of airway patency, work of breathing, and oxygenation/ventilation status, rather than a score alone.
Question 66: A 62-year-old woman presents with central chest pain radiating to her jaw. Her ECG shows ST-segment depression of 2 mm in leads V3-V6 and positive troponin I. Blood pressure is 145/88 mmHg and heart rate is 72 bpm. She is on aspirin 75 mg daily for previous TIA. Which combination of antiplatelet therapy is most appropriate for initial management according to current guidelines?
A. Continue aspirin 75 mg and add clopidogrel 300 mg loading dose
B. Give aspirin 300 mg loading dose and add clopidogrel 600 mg loading dose
C. Continue aspirin 75 mg and add ticagrelor 180 mg loading dose (Correct Answer)
D. Give aspirin 300 mg loading dose and add prasugrel 60 mg loading dose
E. Stop aspirin and give ticagrelor 180 mg loading dose only
Explanation: ***Continue aspirin 75 mg and add ticagrelor 180 mg loading dose***
- For patients with **NSTEMI** already taking maintenance aspirin, the focus is adding a potent **P2Y12 inhibitor**; a 300 mg aspirin loading dose is typically not required unless the last dose was more than 24 hours ago.
- **Ticagrelor** is preferred over clopidogrel for most patients with ACS as it significantly reduces cardiovascular events and mortality, given as an initial **180 mg loading dose**.
*Continue aspirin 75 mg and add clopidogrel 300 mg loading dose*
- While aspirin continuation is appropriate, **clopidogrel** is less potent than ticagrelor and is generally reserved for patients with contraindications to more potent P2Y12 inhibitors or those requiring oral anticoagulation.
- A **300 mg loading dose** of clopidogrel provides less rapid and effective platelet inhibition compared to ticagrelor in the context of NSTEMI.
*Give aspirin 300 mg loading dose and add clopidogrel 600 mg loading dose*
- This patient is already on daily **aspirin 75 mg** for a previous TIA, so an additional **aspirin loading dose** is unnecessary and carries an increased risk of bleeding without significant added benefit.
- A **600 mg clopidogrel loading dose** is a higher dose often used in the context of planned PCI, but **ticagrelor** is generally preferred for initial NSTEMI management due to its superior efficacy.
*Give aspirin 300 mg loading dose and add prasugrel 60 mg loading dose*
- **Prasugrel** is strictly **contraindicated** in patients with a history of **TIA or stroke** due to an increased risk of intracranial hemorrhage, which this patient has.
- Administering an **aspirin loading dose** is also incorrect for a patient already established on maintenance aspirin therapy.
*Stop aspirin and give ticagrelor 180 mg loading dose only*
- **Dual antiplatelet therapy (DAPT)**, consisting of aspirin and a P2Y12 inhibitor, is the cornerstone of management for **NSTEMI** to prevent thrombotic events.
- Stopping **aspirin** would result in monotherapy, which is insufficient and significantly increases the risk of **recurrent ischemic events** and potentially stent thrombosis if PCI is later performed.
Question 67: A 54-year-old man with community-acquired pneumonia is being treated for sepsis in the Emergency Department. His blood pressure is 78/45 mmHg despite 30 mL/kg crystalloid fluid resuscitation. Heart rate is 118 bpm and lactate is 5.2 mmol/L. Which pharmacological intervention should be initiated next according to the Surviving Sepsis Campaign guidelines?
A. Noradrenaline infusion via peripheral cannula (Correct Answer)
B. Adrenaline infusion via central line
C. Dopamine infusion at renal dose
D. Dobutamine infusion targeting increased cardiac output
E. Vasopressin as first-line vasopressor
Explanation: ***Noradrenaline infusion via peripheral cannula***- **Noradrenaline** is the first-line vasopressor therapy recommended for patients in **septic shock** who remain hypotensive despite adequate volume resuscitation.- Current guidelines support the temporary use of noradrenaline via a **peripheral cannula** to avoid delays in maintaining a **Mean Arterial Pressure (MAP) ≥ 65 mmHg** while central access is being established.*Adrenaline infusion via central line*- **Adrenaline** (epinephrine) is designated as a **second-line agent** to be added only when noradrenaline is insufficient to achieve MAP targets.- Initiating it immediately via a central line would cause an unnecessary delay in treatment for a patient who has already failed **fluid resuscitation**.*Dopamine infusion at renal dose*- The use of **"renal-dose" dopamine** for renal protection is no longer recommended and has been proven ineffective in modern sepsis management.- **Dopamine** is associated with a higher risk of **arrhythmias** compared to noradrenaline and is only considered in highly selected patients with low risk of tachyarrhythmias.*Dobutamine infusion targeting increased cardiac output*- **Dobutamine** is indicated only if there is evidence of persistent hypoperfusion despite adequate MAP or if there is documented **myocardial dysfunction**.- It should not be used as the primary agent to correct **vasoplegic hypotension** in the initial stages of septic shock management.*Vasopressin as first-line vasopressor*- **Vasopressin** is categorized as a **second-line vasopressor** that is typically added to noradrenaline to either raise the MAP or decrease the noradrenaline dosage.- It is not recommended as the **sole initial pharmacological intervention** for the management of septic shock.
Question 68: A 49-year-old man with known severe latex allergy presents to the Emergency Department 10 minutes after putting on latex gloves at work. He has facial flushing, generalized urticaria, and reports feeling dizzy. His blood pressure is 92/58 mmHg, heart rate 105 bpm, and oxygen saturation 96% on room air. He has no wheeze. After initial treatment with intramuscular adrenaline, intravenous fluids, and antihistamines, his symptoms resolve. Four hours later he is asymptomatic with stable observations. What is the minimum recommended observation period before discharge for this patient?
A. He can be discharged immediately as he is now asymptomatic
B. Observe for 2 hours after symptom resolution
C. Observe for 6 hours after symptom resolution (Correct Answer)
D. Observe for 12 hours after symptom resolution
E. Admit for 24-hour observation
Explanation: ***Observe for 6 hours after symptom resolution***
- According to **Resuscitation Council (UK)** guidelines and other national protocols, a minimum of **6 hours observation** is recommended for patients who have experienced anaphylaxis and responded well to initial treatment.
- This observation period is crucial to monitor for **biphasic reactions**, which are recurrences of anaphylactic symptoms without further allergen exposure and can occur several hours after the initial resolution.
*He can be discharged immediately as he is now asymptomatic*
- Immediate discharge is unsafe due to the significant risk of a **biphasic reaction**, which can occur in up to 20% of anaphylactic episodes.
- It is vital to ensure sustained **hemodynamic stability** and symptom resolution once the initial effects of adrenaline have worn off.
*Observe for 2 hours after symptom resolution*
- A 2-hour observation period is generally **insufficient** for anaphylaxis, as many biphasic reactions occur beyond this timeframe (e.g., between 1 and 8 hours).
- Shorter observation periods (e.g., 1-2 hours) are typically reserved for milder **allergic reactions** that are solely cutaneous and without systemic features.
*Observe for 12 hours after symptom resolution*
- A 12-hour observation period is usually recommended for patients with a **slow or incomplete response** to initial treatment, those requiring multiple doses of adrenaline, or individuals with severe underlying comorbidities (e.g., severe asthma, cardiovascular disease).
- It is also considered for patients presenting with very severe initial symptoms or a known history of **biphasic reactions**.
*Admit for 24-hour observation*
- Routine 24-hour admission is not typically required for patients who have experienced anaphylaxis and responded rapidly and completely to initial management, as described in this case.
- Prolonged admission, such as 24 hours, is generally reserved for **refractory anaphylaxis** requiring continuous adrenaline infusion, very severe initial presentations, or significant comorbidities that complicate management or discharge.
Question 69: A 41-year-old woman attends the Emergency Department following three episodes of syncope over the past 2 weeks. Each episode was preceded by palpitations and occurred without warning. She has no significant past medical history. Her resting ECG shows sinus rhythm with a short PR interval of 90 milliseconds and a slurred upstroke to the QRS complex. Echocardiography is structurally normal. What is the most likely mechanism of her syncopal episodes?
A. Ventricular tachycardia due to re-entry via accessory pathway
B. Atrioventricular nodal re-entry tachycardia
C. Atrioventricular re-entry tachycardia via accessory pathway (Correct Answer)
D. Atrial fibrillation with rapid ventricular response via accessory pathway
E. Ventricular fibrillation due to shortened refractory period
Explanation: ***Atrioventricular re-entry tachycardia via accessory pathway***
- The patient's ECG shows a **short PR interval** and a **slurred upstroke to the QRS complex (delta wave)**, which are classic findings for **Wolff-Parkinson-White (WPW) syndrome**.
- **Atrioventricular re-entry tachycardia (AVRT)** is the most common tachyarrhythmia in WPW, where a macro-re-entrant circuit is formed between the normal conduction system and the **accessory pathway**, leading to symptomatic palpitations and syncope.
*Ventricular tachycardia due to re-entry via accessory pathway*
- **Ventricular tachycardia** typically originates from the ventricular myocardium and is not the primary mechanism associated with pre-excitation syndromes like WPW.
- Re-entry in WPW specifically involves both the **atria and the ventricles** (AVRT) rather than a circuit isolated within the ventricles.
*Atrioventricular nodal re-entry tachycardia*
- **AVNRT** involves a micro-re-entrant circuit located entirely within the **AV node** (utilizing dual pathways) and does not require an accessory pathway.
- While it is a common cause of supraventricular tachycardia, it would not explain the **delta wave** seen on this patient's resting ECG.
*Atrial fibrillation with rapid ventricular response via accessory pathway*
- This is a life-threatening complication where an accessory pathway with a **short refractory period** conducts high-frequency atrial impulses directly to the ventricles.
- Although it causes syncope, it usually presents as a **grossly irregular** wide-complex tachycardia and is less frequent than AVRT as a cause of recurrent palpitations.
*Ventricular fibrillation due to shortened refractory period*
- **Ventricular fibrillation** is usually a terminal event following an unstable arrhythmia like pre-excited atrial fibrillation rather than a common cause of recurrent, self-limiting syncope.
- It is not a direct consequence of a shortened PR interval but rather a complication of extreme **ventricular rates** exceeding the myocardium's stability.
Question 70: A 55-year-old woman with metastatic breast cancer on chemotherapy presents to the Emergency Department with a 12-hour history of fever, rigors, and general malaise. Her temperature is 38.7°C, heart rate 112 bpm, blood pressure 108/64 mmHg, respiratory rate 20/min. Blood tests show white cell count 1.2 × 10⁹/L, neutrophils 0.4 × 10⁹/L, CRP 145 mg/L. She is diagnosed with neutropenic sepsis. Which antibiotic regimen is most appropriate as first-line empirical therapy according to UK guidelines?
A. Oral co-amoxiclav
B. Intravenous piperacillin-tazobactam (Correct Answer)
C. Intravenous meropenem
D. Intravenous vancomycin and gentamicin
E. Intravenous benzylpenicillin and gentamicin
Explanation: ***Intravenous piperacillin-tazobactam***
- According to **NICE guidelines**, this is the recommended first-line empirical antibiotic as it provides broad-spectrum coverage against both **Gram-positive** and **Gram-negative** organisms, including **Pseudomonas aeruginosa**.
- It must be administered immediately (within 60 minutes) to patients with **neutrophil counts <0.5 × 10⁹/L** and signs of infection to prevent rapid clinical deterioration.
*Oral co-amoxiclav*
- **Oral antibiotics** are insufficient for the initial treatment of acute neutropenic sepsis, which is a medical emergency requiring **rapid systemic delivery** of therapy.
- This regimen does not provide adequate coverage against **Pseudomonas**, a common and highly lethal pathogen in neutropenic patients.
*Intravenous meropenem*
- **Meropenem** is a carbapenem typically reserved as **second-line therapy** for patients who fail to respond to piperacillin-tazobactam or have suspected **ESBL-producing organisms**.
- It may be used first-line only in specific cases of severe **penicillin allergy** or known colonization with resistant bacteria to preserve its efficacy.
*Intravenous vancomycin and gentamicin*
- This combination lacks the broad-spectrum **beta-lactam** foundation required for initial monotherapy; **vancomycin** is usually only added if MRSA or **catheter-related infection** is suspected.
- **Gentamicin** provides good Gram-negative coverage but is generally used as an adjunct rather than a primary treatment due to **nephrotoxicity** and ototoxicity risks.
*Intravenous benzylpenicillin and gentamicin*
- **Benzylpenicillin** has a very narrow spectrum and lacks activity against the majority of hospital-acquired **Gram-negative bacilli** seen in oncology patients.
- This regimen is more common for **neonatal sepsis** or specific community-acquired infections and is not appropriate for the complex flora associated with **neutropenic sepsis**.
