Correct answer: A. Give a cautious intravenous isotonic crystalloid bolus.

The findings suggest inferior STEMI with right ventricular involvement. Hypotension, elevated JVP and clear lungs point toward a preload-dependent right ventricle. A cautious fluid challenge can improve filling while urgent reperfusion proceeds. Nitrates, diuretics and beta-blockade may aggravate hypotension.

Correct answer: B. Intravenous procainamide.

This is pre-excited atrial fibrillation through an accessory pathway. In a hemodynamically stable patient, procainamide is an appropriate treatment option. AV-nodal blocking agents such as adenosine, verapamil, beta-blockers and digoxin may promote preferential conduction through the accessory pathway and increase the risk of ventricular fibrillation. Hemodynamic instability requires synchronized cardioversion.

Correct answer: C. Intravenous calcium gluconate.

Severe hyperkalemia with ECG toxicity requires immediate myocardial membrane stabilization with intravenous calcium. Insulin with glucose and beta-agonists are important for shifting potassium intracellularly but do not replace urgent cardiac membrane stabilization.

Correct answer: D. Arrange immediate expert airway management and invasive ventilation.

Drowsiness, a silent chest, hypoxemia, respiratory slowing and rising carbon dioxide indicate respiratory muscle fatigue and impending arrest. This patient requires immediate critical-care and expert airway escalation.

Correct answer: E. Proceed with emergency reperfusion therapy using systemic thrombolysis.

This is high-risk pulmonary embolism with obstructive shock. Pregnancy increases bleeding considerations but does not prevent life-saving reperfusion when the mother is critically unstable. Specialist multidisciplinary management is required, and alternative reperfusion strategies may be considered when available or when thrombolysis is unsuitable.

Correct answer: A. Begin potassium replacement with isotonic fluid and defer insulin until potassium is above 3.5 mmol/L.

Total-body potassium is depleted in DKA. With significant hypokalemia, insulin can drive potassium further into cells and precipitate dangerous arrhythmia. Potassium and fluid replacement should begin before insulin.

Correct answer: B. Intravenous hydrocortisone with rapid isotonic saline resuscitation and glucose as needed.

Shock, hyponatremia, hyperkalemia and hypoglycemia in a patient with Addison disease who cannot take glucocorticoids is classic adrenal crisis. Treatment must not wait for laboratory confirmation.

Correct answer: C. Norepinephrine infusion.

Persistent hypotension after appropriate initial fluid resuscitation indicates septic shock requiring vasopressor support. Norepinephrine is the preferred first-line vasopressor. Vasopressor initiation should not be unnecessarily delayed solely while waiting for central access.

Correct answer: D. Arrange urgent mechanical thrombectomy assessment.

Recent therapeutic DOAC use can preclude routine intravenous thrombolysis when clinically relevant anticoagulant activity cannot be excluded, but it does not automatically exclude mechanical thrombectomy. This patient has a disabling deficit and a documented proximal large-vessel occlusion.

Correct answer: E. Begin urgent high-dose glucocorticoid therapy and arrange specialist confirmation.

This is highly suspicious for giant cell arteritis with threatened vision. Treatment should begin immediately. Temporal artery imaging or biopsy should be arranged but must not delay glucocorticoid therapy.

Correct answer: A. Obtain blood, urine and cerebrospinal fluid studies, begin empiric parenteral antibiotics and admit.

A febrile infant this young remains at significant risk for invasive bacterial infection even when clinically well appearing.

Correct answer: B. Supplemental oxygen, hydration support, nasal suction as needed and close observation.

This is bronchiolitis with significant hypoxemia and feeding difficulty. Management is primarily supportive. Routine bronchodilators, corticosteroids, antibiotics and chest physiotherapy are not indicated in uncomplicated bronchiolitis.

Correct answer: C. Administer hyperosmolar therapy immediately and obtain critical-care support.

These are clinical features of cerebral injury associated with pediatric DKA. Hypertonic saline or mannitol should be given promptly according to local protocol while critical-care support is obtained. Neuroimaging should not delay emergency treatment.

Correct answer: D. Give dexamethasone and nebulized adrenaline with observation.

Stridor at rest with marked recession indicates clinically important upper-airway obstruction. Corticosteroid reduces airway inflammation and nebulized adrenaline provides more rapid temporary improvement.

Correct answer: E. Immediate resuscitation, antibiotics and urgent operative management.

Perforation and generalized peritonitis make non-operative enema reduction inappropriate. The infant requires stabilization and urgent surgical treatment.

Correct answer: A. Immediate resuscitation and emergency operative gynecologic management.

This patient has suspected ruptured ectopic pregnancy with hemorrhagic shock. Resuscitation, blood-product preparation and emergency surgical management should proceed urgently.

Correct answer: B. Give magnesium sulfate, urgently control severe hypertension, stabilize and plan delivery.

She has preeclampsia with severe features and laboratory evidence concerning for HELLP syndrome. Maternal stabilization, seizure prophylaxis, urgent blood-pressure control and delivery after stabilization are required.

Correct answer: C. Begin uterine massage and oxytocin while initiating hemorrhage resuscitation.

The most likely cause is uterine atony. Immediate management includes uterine massage, uterotonic treatment, circulatory resuscitation and systematic assessment for other causes of postpartum hemorrhage.

Correct answer: D. Immediate sepsis resuscitation, broad-spectrum IV antibiotics and urgent uterine evacuation.

This is septic abortion with retained infected tissue and hemodynamic compromise. Management requires sepsis treatment plus source control.

Correct answer: E. Arrange urgent laparoscopy with detorsion.

Ovarian torsion is a time-sensitive surgical emergency. Doppler findings do not reliably exclude torsion, and temporary improvement in pain does not justify delayed management.

Correct answer: A. Arrange emergency MRI and immediate spinal surgical assessment.

Bladder dysfunction, saddle sensory loss, bilateral radicular symptoms and progressive weakness are classic red flags for cauda equina syndrome. Delayed investigation risks permanent neurological dysfunction.

Correct answer: B. Arrange immediate urologic exploration without delaying for ultrasound.

The presentation is strongly suggestive of testicular torsion. Testicular viability decreases with delay; imaging should not postpone surgical management when clinical suspicion is high.

Correct answer: C. Urgent blood cultures and arthrocentesis, followed promptly by empiric IV antibiotics.

Septic arthritis is a joint- and potentially life-threatening emergency. In a stable patient, blood cultures and urgent synovial aspiration should be obtained before antibiotics when this can occur without clinically important delay.

Correct answer: D. Maintain immediate safety and arrange emergency psychiatric assessment and appropriate secure care.

Intent, a specific plan, preparatory behavior, access to lethal means and imminent timing represent extremely high acute suicide risk. Immediate safety and emergency psychiatric intervention take priority over routine outpatient treatment.

Correct answer: E. Stop serotonergic agents, provide supportive care and benzodiazepines, and consider serotonin antagonism in severe cases.

Rapid onset after a serotonergic interaction plus clonus and hyperreflexia strongly supports serotonin syndrome. Treatment begins with withdrawal of serotonergic agents, supportive care, sedation and temperature control, with escalation according to severity.

Correct answer: A. Begin urgent pressure-lowering treatment and arrange emergency ophthalmologic care.

Acute angle-closure glaucoma threatens permanent vision. Immediate pressure reduction and urgent ophthalmology involvement are required, followed by definitive treatment.

Correct answer: B. Stop allopurinol immediately and arrange emergency multidisciplinary supportive care.

Fifteen-percent epidermal detachment with mucosal involvement is compatible with SJS/TEN overlap. The suspected culprit drug must be stopped immediately and the patient requires specialist supportive management including fluid, wound, pain and ocular care.

Correct answer: C. Intramuscular adrenaline into the anterolateral thigh.

This is life-threatening anaphylaxis with airway, breathing and circulatory compromise. Intramuscular adrenaline is the first-line medication. Airway support, oxygen, intravenous fluids, monitoring and repeat adrenaline may also be required.

Correct answer: B. 5.

Absolute risk reduction = 30% − 8% = 22% = 0.22.

Number needed to treat = 1 ÷ 0.22 = approximately 4.55. NNT is conventionally rounded up to the next whole patient, giving 5.

Correct answer: E. Reduced circulating volume plus NSAID-mediated afferent vasoconstriction and ACE-inhibitor-mediated efferent vasodilation.

This is the classic hemodynamic interaction sometimes called the “triple whammy.” Diuretic use and gastrointestinal fluid loss reduce circulating volume, NSAIDs reduce afferent arteriolar vasodilation by inhibiting prostaglandins, and ACE inhibitors dilate the efferent arteriole. The combined effect can markedly reduce glomerular filtration pressure.