DHA / DOH / MOH exam (UAE) emergency medicine questions

Current BLS guidelines recommend a compression:ventilation ratio of 30:2 for adults when an advanced airway is not in place, with a compression rate of 100-120/min and a depth of 5-6 cm, allowing full chest recoil between compressions. This ratio balances adequate coronary and cerebral perfusion with sufficient ventilation. Once an advanced airway is secured, compressions become continuous with ventilations given every 6 seconds without pausing. Minimizing interruptions to compressions is emphasized because even brief pauses reduce coronary perfusion pressure.

• A. 15:2 is not the recommended adult single-rescuer ratio; it was historically used for two-rescuer pediatric CPR.
• B. A rate of 80-100/min and depth of 3-4 cm are both below the guideline-recommended minimums for effective compressions.
• C. 5:1 is not a recognized ratio in current adult BLS guidelines.

The rhythm described is ventricular fibrillation, a shockable rhythm characterized by chaotic, disorganized electrical activity with no discernible QRS complexes. In a pulseless patient with VF, the priority is immediate unsynchronized defibrillation, as early shock delivery is the single most effective intervention for improving survival. CPR should resume immediately after the shock for two minutes before the rhythm is reassessed. Adrenaline and antiarrhythmics are adjuncts given after the first shock, not substitutes for defibrillation.

• B. Synchronized cardioversion requires an organized rhythm with identifiable R waves, which is absent in VF.
• C. Pacing is used for symptomatic bradycardia with a pulse, not for pulseless VF.
• D. VF is shockable; withholding defibrillation and relying on adrenaline alone delays the most effective therapy and worsens outcomes.

In non-shockable rhythms such as asystole and PEA, adrenaline 1 mg IV (1:10,000 solution) should be given as soon as possible and repeated every 3-5 minutes throughout the resuscitation. Adrenaline's alpha-adrenergic effect increases coronary and cerebral perfusion pressure during CPR. Atropine is no longer recommended in cardiac arrest algorithms for asystole or PEA. Amiodarone has a role only in shockable rhythms refractory to defibrillation, not in asystole.

• B. Atropine has been removed from the pulseless arrest algorithm as it has not shown benefit in asystole or PEA.
• C. Every 10 minutes is too infrequent; the recommended interval is 3-5 minutes.
• D. Amiodarone is indicated for shock-refractory VF/pulseless VT, not for asystole.

For refractory VF/pulseless VT persisting after three shocks, amiodarone 300 mg IV bolus is given, followed by continuation of CPR and delivery of the next shock as part of the ongoing cycle. Amiodarone stabilizes the cardiac membrane and increases the likelihood that subsequent defibrillation will succeed. A second dose of 150 mg may be given if VF/VT persists. Defibrillation is never withheld while waiting for drug effect; shocks continue at each rhythm check regardless of drug administration.

• A. Withholding further defibrillation would remove the most effective therapy for VF and delay return of spontaneous circulation.
• C. Delaying amiodarone until after two more shocks is not guideline-based; it should be given once VF is refractory after three shocks.
• D. Synchronized cardioversion is inappropriate for pulseless VF, which requires unsynchronized shocks.

Absent breath sounds on one side with distended neck veins following a central line attempt strongly suggests tension pneumothorax from pleural puncture, one of the reversible 4T causes of PEA (Tension pneumothorax, Tamponade, Toxins, Thromboembolism). The mechanism is accumulation of air in the pleural space causing mediastinal shift, impaired venous return, and obstructive shock. Immediate needle decompression or finger thoracostomy is required before further ACLS drugs will be effective. Recognizing the clinical context (recent subclavian line attempt) is key to identifying this specific reversible cause.

• A. Cardiac tamponade would present with muffled heart sounds and equal, not asymmetric, breath sounds, and is less linked to subclavian line attempts than pleural puncture.
• B. Hypovolemia would not explain unilateral absent breath sounds or jugular venous distension.
• C. Pulmonary thromboembolism typically does not cause unilateral absent breath sounds following a line insertion attempt.

Post-ROSC care requires avoiding both hyperoxia and hypoxia; oxygen should be titrated to maintain SpO2 94-98% rather than leaving FiO2 at 1.0, since hyperoxia can worsen neurological injury through oxidative stress. Targeted temperature management with a core temperature maintained between 32°C and 36°C for at least 24 hours is recommended to reduce cerebral metabolic demand and improve neurological outcomes. Fever should be actively avoided and treated if it occurs. These measures are part of a bundle that also includes hemodynamic optimization and early coronary angiography when indicated.

• B. Maintaining FiO2 1.0 causes hyperoxia, and allowing fever worsens secondary brain injury after cardiac arrest.
• C. Omitting temperature control removes a key evidence-based intervention for neuroprotection after ROSC.
• D. SpO2 100% often reflects hyperoxia, and temperatures below 30°C risk arrhythmias and coagulopathy, below the recommended range.

Tension pneumothorax is a clinical diagnosis made from signs of respiratory distress, hypotension, tracheal deviation away from the affected side, hyperresonance, and absent breath sounds; imaging should never delay treatment. Immediate needle decompression is performed in the second intercostal space at the midclavicular line on the affected side to relieve the tension and restore venous return. This is followed promptly by formal tube thoracostomy. Delaying decompression for imaging risks cardiac arrest from obstructive shock.

• A. CT is too slow and is never indicated in a hemodynamically unstable tension pneumothorax.
• B. Fluids alone do not relieve the mechanical obstruction to venous return and are inadequate as sole therapy.
• D. Imaging delays life-saving decompression in a clinically obvious tension pneumothorax.

A silent chest indicates airflow is so severely restricted that insufficient air movement generates audible wheeze, and it is a classic marker of life-threatening asthma alongside SpO2 below 92%, PEFR below 33% predicted, bradycardia or arrhythmia, hypotension, exhaustion, confusion, and a normal or rising PaCO2. Tachypnea, tachycardia, and inability to complete sentences are features of acute severe asthma but do not by themselves denote the life-threatening category. Recognizing a silent chest is critical because it can precede imminent respiratory arrest. Immediate senior help, intravenous therapy, and consideration of intensive care are required.

• A. Tachycardia above 110/min is a feature of severe asthma; life-threatening asthma is marked by bradycardia or arrhythmia.
• C. Inability to complete sentences is a feature of severe asthma, not specific to the life-threatening category.
• D. Tachypnea above 25/min is a feature of severe, not life-threatening, asthma.

Nebulized or repeated inhaled short-acting beta-2 agonist such as salbutamol, via oxygen-driven nebulizer or spacer device, is the first-line bronchodilator for acute asthma exacerbations of any severity. It produces rapid bronchodilation with a favorable safety profile compared with systemic agents. Intravenous aminophylline is reserved for life-threatening asthma poorly responsive to initial therapy and carries a narrow therapeutic index. Oral and subcutaneous routes are slower in onset and are not preferred when inhaled therapy can be delivered effectively.

• A. Subcutaneous beta-agonists are reserved for situations where inhaled therapy cannot be delivered and have more systemic side effects.
• C. Intravenous aminophylline is a second-line option used only in near-fatal or refractory cases, not first-line therapy.
• D. Oral salbutamol has slower onset and lower efficacy than the inhaled route and is not first-line in acute exacerbations.

Acute epiglottitis is a clinical diagnosis suggested by the toxic appearance, drooling, tripod positioning, and muffled voice, and any attempt to examine the throat or agitate the child can precipitate complete airway obstruction. The safest and most appropriate next step is immediate transfer to the operating room, accompanied by anesthesia and ENT or senior airway specialists, to secure the airway under controlled conditions, typically with inhalational induction. Investigations and oral examination should be avoided until the airway is secured. Blood tests, IV access, and throat examination should never precede airway control in a child with suspected epiglottitis.

• B. Imaging causes dangerous delay and agitation; it is not required when the clinical picture is characteristic and the child is unstable.
• C. Nebulized epinephrine is used for croup, not epiglottitis, and observation without securing the airway risks sudden obstruction.
• D. Examining the throat can trigger laryngospasm and complete airway obstruction and must be avoided.

In a stable child with suspected foreign body aspiration, inspiratory and expiratory chest radiographs are the appropriate initial investigation, looking for air trapping, mediastinal shift, atelectasis, or occasionally a radio-opaque object, even though many aspirated foreign bodies are radiolucent and the film can be normal. Chest X-ray helps support the diagnosis and localize the side while rigid bronchoscopy is arranged, which remains both diagnostic and therapeutic. CT is more sensitive but involves higher radiation and is not first-line in a young, unstable-to-sedate child. Spirometry is impractical and unreliable at this age.

• A. Spirometry requires cooperation and technique that an 18-month-old cannot perform.
• B. CT chest involves higher radiation exposure and sedation requirements and is not the first-line test in this age group.
• C. Bronchoscopy, specifically rigid bronchoscopy, is the definitive diagnostic and therapeutic procedure but follows initial imaging in a stable child.

Ischemic stroke within the preceding 3 months is an absolute contraindication to fibrinolytic therapy because of the markedly increased risk of hemorrhagic transformation and intracranial bleeding. In this situation, the patient should be transferred for primary percutaneous coronary intervention even if this causes some delay, since thrombolysis is unsafe regardless of door-to-needle considerations. Dose reduction or blood pressure control does not mitigate an absolute contraindication. Guidelines list recent ischemic stroke (within 3 months), any prior hemorrhagic stroke, active bleeding, and suspected aortic dissection among the absolute contraindications to thrombolysis.

• B. Dose reduction does not eliminate the risk; recent ischemic stroke remains an absolute contraindication regardless of agent or dose.
• C. Blood pressure control addresses a relative contraindication but does not override the absolute contraindication of recent stroke.
• D. Any fibrinolytic, regardless of monitoring, is contraindicated within 3 months of an ischemic stroke.

The combination of tearing back pain, blood pressure discrepancy between limbs, and a new diastolic murmur (suggesting aortic regurgitation) strongly suggests aortic dissection, which requires urgent confirmation with CT angiography in a hemodynamically stable patient, as it rapidly delineates the extent of the dissection flap and guides surgical versus medical management. Unlike ACS, dissection pain is typically abrupt, tearing, and migrates to the back, and ECG changes are usually absent unless the dissection involves a coronary ostium. Stress testing is contraindicated in suspected dissection due to the risk of rupture. D-dimer may be used as a rule-out adjunct in low-probability cases but is not confirmatory and does not replace imaging.

• B. D-dimer alone cannot confirm the diagnosis; definitive diagnosis requires imaging.
• C. Exercise stress testing is contraindicated in suspected acute aortic dissection because of rupture risk.
• D. Coronary angiography assesses the coronary arteries and is not the test of choice for diagnosing dissection, and catheter manipulation could worsen it.

The clinical picture of positional pleuritic chest pain, a pericardial friction rub, and diffuse concave ST elevation with PR depression following a viral prodrome is characteristic of acute pericarditis. First-line treatment combines a high-dose NSAID such as ibuprofen with colchicine, which reduces symptom duration and significantly lowers the risk of recurrence. Anticoagulation is avoided in pericarditis because it can promote hemorrhagic transformation into the pericardial space. Antiplatelet therapy and diuretics have no role in uncomplicated viral pericarditis.

• A. Anticoagulation is avoided in acute pericarditis due to the risk of hemorrhagic pericardial effusion.
• B. Diuretics are not indicated for uncomplicated pericarditis without evidence of heart failure or effusion requiring drainage.
• D. Dual antiplatelet therapy is used for ACS, not for pericarditis, which is an inflammatory, not thrombotic, process.

Hypotension, elevated jugular venous pressure, and muffled heart sounds constitute Beck's triad, classic for cardiac tamponade, here likely due to a malignant pericardial effusion. The pulsus paradoxus (inspiratory systolic drop greater than 10 mmHg) further supports this. Bedside transthoracic echocardiography is the best initial test, as it rapidly demonstrates pericardial effusion with signs of hemodynamic compromise such as right ventricular diastolic collapse and respiratory variation in ventricular filling. Chest X-ray may show an enlarged cardiac silhouette but cannot confirm tamponade physiology, ECG may show low voltage or electrical alternans but is nonspecific, and BNP is not useful for diagnosing tamponade.

• A. Chest X-ray may suggest cardiomegaly but cannot confirm tamponade or hemodynamic compromise.
• B. BNP reflects ventricular stretch in heart failure and is not a diagnostic test for tamponade.
• C. ECG findings such as electrical alternans are nonspecific and insufficient to confirm the diagnosis.

This patient has a wide-complex tachycardia with signs of hemodynamic instability (hypotension, altered mental status, poor perfusion), which mandates immediate synchronized cardioversion regardless of the underlying rhythm. Delaying definitive treatment to trial pharmacological agents risks deterioration to cardiac arrest. Amiodarone may be used in stable wide-complex tachycardia, but this patient's instability makes cardioversion the priority. Adenosine is used for stable regular narrow-complex tachycardia and may be ineffective or harmful here. Oral medications have no role in an unstable emergency.

• A. Adenosine is used for stable narrow-complex SVT, not for an unstable wide-complex tachycardia.
• B. Oral agents have too slow an onset for an unstable patient with hypotension and altered mentation.
• C. Antiarrhythmic infusion is appropriate for stable wide-complex tachycardia, not for one causing hemodynamic collapse, which needs immediate cardioversion.

In a hemodynamically stable patient with regular narrow-complex supraventricular tachycardia unresponsive to vagal maneuvers, intravenous adenosine is first-line, given as a rapid 6 mg bolus followed by a rapid saline flush, with a repeat dose of 12 mg if the first is unsuccessful. Adenosine transiently blocks conduction through the atrioventricular node, interrupting the reentry circuit responsible for most SVTs. Verapamil is a reasonable second-line option but should be given slowly over several minutes, not as a rapid push, and digoxin has a delayed onset unsuitable for acute termination. Amiodarone is not first-line for simple SVT and rapid administration risks hypotension.

• A. Verapamil must be given slowly over 2 minutes, not as a rapid 1-minute push, and is second-line after adenosine.
• C. Digoxin has a slow onset of action and is not used for acute termination of SVT.
• D. Rapid bolus amiodarone is not standard first-line therapy for stable narrow-complex SVT and can cause hypotension.

In a hemodynamically stable patient with new-onset atrial fibrillation and rapid ventricular response, initial management focuses on rate control using an intravenous beta-blocker (or non-dihydropyridine calcium channel blocker), which is effective, safe, and does not require delay for anticoagulation assessment. Although the onset is within 48 hours, electrical cardioversion is not mandatory as first step and, if elected, generally warrants consideration of thromboembolic risk and anticoagulation. Flecariamide-class pill-in-pocket strategies are reserved for selected, pre-evaluated paroxysmal AF patients without structural heart disease, not as initial ED management. Digoxin is a second-line option with slower onset, particularly in patients with reduced ejection fraction or sedentary lifestyle, not the preferred first-line agent here.

• A. Flecainide pill-in-the-pocket requires prior safety testing and is not appropriate as an untried initial ED strategy.
• C. Cardioversion without consideration of anticoagulation and thromboembolic risk is not the recommended first step even within the early time window.
• D. Digoxin is a second-line rate control agent with slower onset and is not preferred as first-line therapy in this patient.

Severe hyperkalemia with ECG changes (widened QRS, loss of P waves) indicates impending malignant arrhythmia and requires immediate membrane stabilization. Intravenous calcium gluconate raises the threshold potential, directly antagonizing the cardiac membrane effects of hyperkalemia within minutes, though it does not lower serum potassium. Insulin-glucose, bicarbonate, and beta-agonists shift potassium intracellularly but act more slowly and should follow calcium when ECG changes are present. Calcium should always precede potassium-shifting agents in symptomatic or ECG-positive hyperkalemia.

• A. Shifts potassium intracellularly but acts slower than calcium and should not be given first when ECG changes are present.
• B. Shifts potassium intracellularly but has a delayed onset and is not first-line for immediate membrane stabilization.
• D. A potassium-shifting agent that works more slowly than calcium and is not the immediate priority with ECG changes.

The scenario describes torsades de pointes precipitated by QT-prolonging drugs (haloperidol and erythromycin) acting synergistically to prolong repolarization. Intravenous magnesium sulfate is first-line treatment regardless of serum magnesium level, as it suppresses the triggered activity underlying torsades even when levels are normal. The offending QT-prolonging drugs must also be stopped and electrolytes corrected. Amiodarone and other class III agents further prolong the QT interval and can worsen torsades, and cardioversion is reserved for hemodynamically unstable or sustained episodes.

• A. A QT-prolonging antiarrhythmic that can worsen torsades de pointes and is not appropriate here.
• B. Not first-line for torsades; used more for monomorphic ventricular tachycardia from ischemia.
• D. Reserved for hemodynamically unstable or sustained torsades, not for this self-terminated stable episode.

This patient has cardiogenic shock from acute myocardial infarction with severely reduced ejection fraction, causing pump failure. The hemodynamic profile is low cardiac output with compensatory high systemic vascular resistance (cold, clammy extremities) and high filling pressures (elevated jugular venous pressure, pulmonary crepitations from backward failure). This distinguishes it from hypovolemic shock, which has low filling pressures from volume depletion, and septic shock, which classically shows high cardiac output with low systemic vascular resistance (warm shock) early in its course. Obstructive shock, such as from tension pneumothorax or cardiac tamponade, shows elevated central venous pressure from a mechanical cause rather than pump failure itself.

• A. Describes obstructive shock from a mechanical cause, not primary pump failure as seen with this low ejection fraction.
• B. Describes distributive (septic) shock, inconsistent with the cold extremities and evidence of pump failure here.
• D. Describes hypovolemic shock, inconsistent with the elevated JVP and pulmonary crepitations indicating volume overload.

This patient meets criteria for septic shock with hypotension and lactate above 2 mmol/L despite presumed adequate intravascular volume. The Surviving Sepsis Campaign hour-1 bundle recommends simultaneous measurement of lactate, obtaining blood cultures prior to antibiotics, administration of broad-spectrum antibiotics, and a 30 mL/kg crystalloid bolus for hypotension or lactate ≥4 mmol/L, all performed without delay. Antibiotics must not be delayed for culture results, and cultures should ideally be drawn before antibiotics whenever this does not significantly delay treatment. Vasopressors are added if hypotension persists after adequate fluid resuscitation, not as an initial substitute for fluids and antibiotics.

• A. Antibiotics must not be withheld pending cultures; delaying antibiotics increases mortality in septic shock.
• B. Antibiotics should not be delayed for cultures, and fluids are also required immediately given the hypotension and elevated lactate.
• D. Vasopressors are added after fluid resuscitation fails to restore perfusion, not used as an initial step before fluids and antibiotics.

This patient shows signs of hypovolemic (hemorrhagic) shock from a closed femur fracture, with tachycardia, hypotension, and delayed capillary refill. Current trauma resuscitation guidelines recommend an initial bolus of warmed balanced crystalloid solution, such as Ringer's lactate or Plasma-Lyte, typically given in 1 liter (or 10-20 mL/kg) increments, with early transition to blood products if the patient remains unstable or hemorrhage is significant. Balanced crystalloids avoid the hyperchloremic metabolic acidosis associated with large-volume normal saline. Dextrose solutions distribute mostly into the intracellular space and are ineffective for intravascular volume expansion, hypotonic saline worsens cerebral edema risk and provides poor volume expansion, and starch-based colloids are avoided due to risks of acute kidney injury and coagulopathy.

• A. Distributes rapidly into the intracellular compartment and provides minimal sustained intravascular volume expansion.
• B. Synthetic colloids carry risks of acute kidney injury and coagulopathy and are not recommended for trauma resuscitation.
• D. A hypotonic solution that poorly expands the intravascular space and risks cerebral edema; not appropriate for shock resuscitation.

Persistent hypotension despite adequate initial fluid resuscitation defines fluid-refractory septic shock, requiring vasopressor support to restore mean arterial pressure and organ perfusion. Norepinephrine is the first-line vasopressor recommended by the Surviving Sepsis Campaign guidelines, acting predominantly on alpha-1 adrenergic receptors to increase systemic vascular resistance with modest beta-1 inotropic effect and a lower risk of arrhythmia than dopamine. Dopamine is a second-line alternative with a higher risk of tachyarrhythmias, and dobutamine is an inotrope used for myocardial dysfunction rather than as a primary vasopressor. Repeated large-volume fluid boluses without reassessment risk fluid overload once initial resuscitation targets have not restored perfusion.

• B. An inotrope used to augment cardiac contractility in cardiogenic states, not a first-line vasopressor for septic shock.
• C. Further unguided fluid boluses risk volume overload; vasopressor support is indicated for fluid-refractory hypotension.
• D. A second-line vasopressor associated with higher rates of tachyarrhythmia compared with norepinephrine.

This patient meets criteria for activation of the massive transfusion protocol (hemodynamic instability with ongoing hemorrhage unresponsive to initial crystalloid, requiring emergency surgery). Current trauma resuscitation guidelines recommend early balanced transfusion of packed red cells, fresh frozen plasma and platelets in a 1:1:1 ratio to prevent dilutional coagulopathy, based on evidence from the PROPPR trial. This approach reduces death from hemorrhage in the first 24 hours compared with red-cell-predominant strategies. Waiting for laboratory results delays resuscitation and worsens the trauma-induced coagulopathy triad of acidosis, hypothermia and coagulopathy.

• B. Red-cell-only transfusion worsens dilutional coagulopathy and does not replace clotting factors or platelets.
• C. Delaying transfusion for laboratory confirmation in an unstable hemorrhaging patient increases mortality risk.
• D. A 4:1 ratio under-replaces plasma relative to red cells and increases risk of coagulopathy.

The primary survey follows the ABCDE sequence, and airway with cervical spine protection takes priority over all other assessments. Gurgling breath sounds indicate airway obstruction by blood, secretions or vomitus, which must be cleared immediately by suctioning before proceeding to breathing or circulation assessment. An obstructed airway will cause death faster than any other injury, so it must be addressed before imaging or circulatory access. Only once the airway is secured and patent should the examiner move on to assessing breathing and ventilation.

• A. Neurological assessment is step D in the primary survey and must wait until airway, breathing and circulation are addressed.
• B. Circulatory access is part of step C and should not precede securing a patent airway.
• D. Imaging is appropriate later in the breathing assessment but is not the immediate priority when the airway itself is compromised.

The combination of hypertension, bradycardia and irregular respiration constitutes Cushing's triad, a late sign of rising intracranial pressure caused by brainstem compression, typically from an expanding mass lesion such as an intracranial hematoma. The physiological mechanism involves the Cushing reflex, where elevated intracranial pressure reduces cerebral perfusion, triggering a sympathetic surge that raises blood pressure to maintain cerebral perfusion, which in turn stimulates baroreceptors causing reflex bradycardia. The dilated, sluggishly reactive pupil on the same side indicates early uncal herniation with third cranial nerve compression. This constellation demands immediate neurosurgical evaluation and measures to reduce intracranial pressure.

• A. Hemorrhagic shock produces hypotension and tachycardia, the opposite of the hypertension and bradycardia seen here.
• B. The vital sign pattern and pupillary finding are explained by a unifying intracranial process, not an isolated cardiac arrhythmia.
• D. Neurogenic shock causes hypotension and bradycardia, not the hypertension seen in this patient.

This clinical course, a lucid interval followed by rapid neurological deterioration after temporal trauma, is classic for an extradural (epidural) hematoma, often from laceration of the middle meningeal artery following a temporal bone fracture. On CT, extradural hematomas appear as biconvex (lens-shaped) hyperdense collections that do not cross suture lines, because the dura is tightly adherent to the skull at the sutures, limiting the collection's spread. In contrast, subdural hematomas appear crescent-shaped and can cross suture lines since they form between the dura and arachnoid. Rapid neurosurgical evacuation is required once the diagnosis is confirmed to prevent fatal herniation.

• A. Diffuse cerebral edema describes diffuse axonal injury or global hypoxic injury, not a focal hematoma with a lucid interval.
• B. Blood within the basal cisterns and sulci describes traumatic subarachnoid hemorrhage, not the biconvex collection typical of this presentation.
• D. A crescent-shaped collection crossing suture lines describes a subdural hematoma, which typically has a more gradual course, especially in elderly or anticoagulated patients.

In a hemodynamically unstable patient with blunt abdominal trauma and a positive FAST scan showing free intraperitoneal fluid, the diagnosis of hemoperitoneum is established and further imaging would only delay definitive treatment. The next step is immediate transfer to the operating room for exploratory laparotomy to control hemorrhage, since this patient's instability despite initial fluids indicates ongoing bleeding that will not be controlled by resuscitation alone. CT scanning is reserved for hemodynamically stable patients where more detailed characterization of injury is needed and time permits. Delaying surgery in an unstable patient with confirmed hemoperitoneum increases mortality risk.

• B. CT scanning requires a hemodynamically stable patient and would dangerously delay hemorrhage control in this unstable patient.
• C. Diagnostic peritoneal lavage is largely obsolete and unnecessary when FAST has already confirmed hemoperitoneum.
• D. Continued resuscitation and repeat imaging delays definitive hemorrhage control in a patient who is already unstable.

In a hemodynamically unstable patient with a suspected unstable pelvic fracture, immediate application of a pelvic binder at the level of the greater trochanters reduces pelvic volume and tamponades venous and bony bleeding, which is the predominant source of hemorrhage in pelvic trauma. This simple, rapid, noninvasive measure is performed as part of circulatory management in the primary survey and should not be delayed for imaging confirmation when the clinical diagnosis of pelvic instability is apparent. Once the binder is applied, resuscitation continues and further imaging or interventions such as angiography or definitive fixation are pursued based on the response to initial stabilization. Repeated manual pelvic compression to assess instability should be avoided as it may dislodge clot and worsen hemorrhage.

• B. Imaging should not delay a life-saving, low-risk intervention like binder application when clinical findings already suggest pelvic instability and the patient is unstable.
• C. External fixation is a definitive orthopedic procedure requiring specialized equipment and is not the immediate emergency department intervention.
• D. Angiographic embolization is considered after initial stabilization with a binder if hemorrhage continues, not as the first step.

Diabetic ketoacidosis is diagnosed by the triad of hyperglycemia (glucose typically above 11 mmol/L, though it can be lower in euglycemic DKA), metabolic acidosis (pH below 7.30, bicarbonate below 15-18 mmol/L), and ketosis (significant ketonuria or ketonemia). This patient meets all three criteria with glucose 22 mmol/L, pH 7.18, bicarbonate 10 mmol/L, and large urinary ketones. Each component must be present; isolated hyperglycemia or isolated acidosis without ketosis does not establish the diagnosis.

• B. Normal glucose, pH, bicarbonate, and absent ketones exclude DKA entirely.
• C. A normal pH and bicarbonate exclude significant acidosis, which is required for the diagnosis.
• D. Acidosis without ketonuria suggests an alternative cause of metabolic acidosis rather than DKA.

The first priority in DKA management is restoring circulating volume with intravenous isotonic (0.9%) saline, since most patients are significantly volume-depleted and hypotensive, as in this case. Insulin is started only after initial fluid resuscitation has begun, typically within the first hour, because insulin alone can worsen hypotension by driving potassium and water intracellularly before volume is restored. Potassium replacement is only added once levels fall below about 5.3 mmol/L, which is not yet the case here at 5.8 mmol/L. Bicarbonate is not routinely used in DKA regardless of pH, as it does not improve outcomes and can cause paradoxical CNS acidosis.

• A. Insulin should follow, not precede, initial fluid resuscitation in a hypotensive patient to avoid worsening hemodynamic instability.
• C. Potassium is already elevated at 5.8 mmol/L; replacement is only started once levels fall below approximately 5.3 mmol/L.
• D. Bicarbonate is not recommended in routine DKA management regardless of pH, as it does not improve outcomes.

This presentation of hypothermia, bradycardia, hypotension, and delayed reflexes in an elderly patient with known hypothyroidism is characteristic of myxedema coma, often precipitated by cold exposure. First-line treatment is intravenous levothyroxine (with or without liothyronine), along with intravenous hydrocortisone to cover possible coexisting adrenal insufficiency, plus passive warming and supportive care. This contrasts with thyroid storm, which presents with fever, tachycardia, and agitation and is treated with antithyroid drugs, beta-blockers, and iodine. Mortality in myxedema coma remains high without prompt thyroid hormone replacement.

• A. Potassium iodide blocks thyroid hormone release in thyroid storm and has no role in the hypothyroid state of myxedema coma.
• B. Propranolol treats the tachycardia and sympathetic overactivity of thyroid storm; this patient is bradycardic from hypothyroidism.
• D. Propylthiouracil is an antithyroid drug used for thyroid storm (hyperthyroidism), not for myxedema coma, which results from thyroid hormone deficiency.

This patient has adrenal crisis precipitated by intercurrent infection, which increases cortisol requirements beyond her usual replacement dose in primary adrenal insufficiency. Immediate treatment is intravenous hydrocortisone (typically 100 mg bolus followed by continuous infusion or divided doses), combined with aggressive intravenous isotonic saline resuscitation and correction of hypoglycemia. Hydrocortisone is preferred because, unlike synthetic steroids such as dexamethasone, it has mineralocorticoid activity that helps restore the sodium and volume deficit alongside its glucocorticoid effect. Oral therapy is inappropriate in a hemodynamically unstable, vomiting patient who cannot reliably absorb medication.

• A. Oral administration is unreliable in a vomiting, hemodynamically unstable patient who needs immediate parenteral therapy.
• B. Dexamethasone has glucocorticoid activity but negligible mineralocorticoid effect, making it less suitable than hydrocortisone for acute adrenal crisis.
• D. Fludrocortisone is a pure mineralocorticoid used for chronic maintenance, not acute crisis, and lacks sufficient glucocorticoid activity for emergency treatment.

When the plasma paracetamol concentration at a known time point falls above the treatment line on the paracetamol nomogram, intravenous N-acetylcysteine should be started immediately regardless of symptoms, since hepatotoxicity develops over days and clinical signs lag behind biochemical injury. At 5 hours post-ingestion, a level of 160 mg/L is well above the standard treatment line (which is roughly 150 mg/L at 4 hours and declines thereafter), indicating significant risk of hepatotoxicity. Treatment should not be delayed for a repeat level, as NAC is most effective when started within 8 hours of ingestion. Activated charcoal may still be considered if the patient presents within 1-2 hours of a large ingestion, but it does not replace NAC once the level is above the treatment threshold.

• A. Absence of symptoms does not exclude ongoing hepatotoxic risk; treatment is based on the nomogram level, not symptoms.
• B. Charcoal alone is inadequate once the level is above the treatment line; NAC is required to prevent hepatotoxicity.
• D. Waiting for a repeat level delays NAC unnecessarily when the current level already clearly exceeds the treatment threshold.

The initial intravenous naloxone dose for suspected opioid overdose with respiratory depression is 0.4-2 mg, repeated every 2-3 minutes as needed up to several milligrams if there is no response. A positive response, confirming the opioid etiology, is rapid improvement in respiratory rate, level of consciousness, and oxygenation typically within 1-2 minutes. Because naloxone's duration of action (roughly 30-90 minutes) is often shorter than that of the causative opioid, repeated dosing or an infusion and a period of observation are needed to prevent re-sedation. Starting with a very high dose is avoided outside cardiac arrest because it can precipitate acute withdrawal and agitation in opioid-dependent patients.

• A. A 10 mg bolus is excessive for initial titration and risks precipitating severe acute withdrawal; standard dosing starts at 0.4-2 mg.
• C. Naloxone's effect is short-lived (30-90 minutes), not sustained for 6 hours, which is why re-sedation monitoring is required.
• D. Pupil changes alone without respiratory improvement would not confirm adequate reversal of the life-threatening respiratory depression.

The combination of bradycardia, miosis, excessive salivation, bronchorrhea, wheeze, and fasciculations is a classic cholinergic toxidrome from organophosphate poisoning, caused by acetylcholinesterase inhibition and accumulation of acetylcholine at muscarinic and nicotinic receptors. Atropine is a competitive muscarinic antagonist that reverses the muscarinic effects (bradycardia, secretions, bronchospasm) and is titrated rapidly until secretions dry and breathing improves, often requiring large cumulative doses. Pralidoxime may be added to reactivate acetylcholinesterase but atropine takes priority for immediate stabilization. Early, aggressive atropinization reduces mortality from respiratory failure.

• A. Naloxone reverses opioid toxicity, which presents with pinpoint pupils and respiratory depression but not salivation, wheeze, or fasciculations.
• B. Activated charcoal alone does not address the life-threatening cholinergic crisis already present and is insufficient as sole management.
• C. Flumazenil reverses benzodiazepine sedation and has no role in a cholinergic toxidrome; it can also precipitate seizures.

Standard two-wavelength pulse oximeters measure the absorbance of light at wavelengths that cannot reliably differentiate carboxyhemoglobin from oxyhemoglobin, so the device reports a falsely normal or near-normal saturation despite significant functional hypoxia. This is a well-known pitfall in carbon monoxide poisoning, where the diagnosis relies on clinical suspicion and measurement of carboxyhemoglobin level via co-oximetry or arterial/venous blood gas. Treatment is high-flow 100% oxygen via non-rebreather mask (or hyperbaric oxygen in severe cases) regardless of the oximetry reading, as it accelerates dissociation of carbon monoxide from hemoglobin. Delayed recognition due to false reassurance from oximetry can lead to severe hypoxic injury.

• B. Probe malposition is a possible general error but does not explain the specific, well-documented false normal reading seen in carbon monoxide poisoning.
• C. Carbon monoxide does not cause the oximetry inaccuracy through vasodilation; the error is due to spectral overlap of carboxyhemoglobin and oxyhemoglobin.
• D. This oximetry limitation applies to carbon monoxide poisoning regardless of underlying lung disease, not specifically to COPD patients.

This patient has heat stroke, defined by core temperature above 40°C with central nervous system dysfunction following heat exposure. The single most important intervention is rapid reduction of core temperature, ideally by cold/ice water immersion or aggressive evaporative cooling with fanning and misting, since mortality correlates directly with duration and degree of hyperthermia. Intravenous fluids and supportive care are given concurrently, but cooling takes absolute priority over other measures. Antipyretics such as paracetamol are ineffective in heat stroke because the hyperthermia is not mediated by hypothalamic prostaglandin resetting as in infectious fever.

• A. Paracetamol acts on hypothalamic thermoregulation in infectious fever and is ineffective in heat stroke, where the problem is failure of heat dissipation, not a raised set point.
• B. There is no indication of infection here; antibiotics are not indicated and do not treat the underlying hyperthermia.
• D. Sedation may be needed for shivering or severe agitation but does not address the life-threatening hyperthermia itself and is not the first priority.

A simple febrile seizure is generalized, lasts less than 15 minutes, occurs only once in 24 hours, and is followed by prompt return to baseline mental status, exactly as seen in this child aged 6 months to 5 years with fever and no central nervous system infection or prior afebrile seizures. Management is reassurance of the family, antipyretics for comfort, and treating the source of fever; routine neuroimaging, electroencephalography, and lumbar puncture are not required when there are no red flags. Red flags that would suggest a complex febrile seizure or alternative diagnosis include focal seizure activity, duration over 15 minutes, recurrence within the same illness, incomplete recovery, or signs of meningism. Recognizing simple febrile seizures avoids unnecessary investigation and parental anxiety.

• A. Lumbar puncture is reserved for children with signs of meningism, prolonged altered consciousness, or other red flags, not for a reassuring simple febrile seizure.
• B. A single seizure in the context of fever and prompt return to baseline is not epilepsy and does not require antiepileptic therapy.
• C. Complex febrile seizures are focal, prolonged beyond 15 minutes, or recurrent within 24 hours, none of which are present in this case.

The recommended intramuscular adrenaline dose in anaphylaxis is 0.01 mg/kg of a 1:1000 (1 mg/mL) solution, up to a maximum single dose of 0.5 mg in children. For this 15 kg child, the dose is 15 kg multiplied by 0.01 mg/kg, giving 0.15 mg. Since the solution contains 1 mg per mL, 0.15 mg corresponds to a volume of 0.15 mL, administered intramuscularly into the anterolateral thigh. Accurate weight-based calculation is essential because adrenaline has a narrow safety margin and overdosing can cause dangerous arrhythmias or hypertension.

• A. This volume corresponds to a tenfold underdose, which would deliver only 0.015 mg and be clinically inadequate for anaphylaxis.
• B. This volume corresponds to a tenfold overdose, which could cause dangerous tachyarrhythmia or severe hypertension.
• C. This volume delivers 0.5 mg, more than three times the calculated weight-based dose for this child.

In a hemodynamically stable woman with a positive pregnancy test and suspicious symptoms, the first-line approach to confirm or exclude ectopic pregnancy is quantitative serum beta-hCG paired with transvaginal ultrasound, which can usually identify an intrauterine pregnancy once beta-hCG exceeds the discriminatory zone (around 1500-2000 IU/L). Absence of an intrauterine gestational sac at this beta-hCG level, especially with an adnexal mass or free fluid, strongly suggests ectopic pregnancy. Serial beta-hCG measurements every 48 hours may be needed if the initial ultrasound is inconclusive and the patient remains stable. Diagnostic laparoscopy is reserved for cases with hemodynamic instability or when imaging and hormone trends remain equivocal.

• A. Plain abdominal X-ray has no role in diagnosing ectopic pregnancy and does not visualize early gestational structures.
• B. Laparoscopy is an invasive surgical procedure reserved for instability or diagnostic uncertainty after noninvasive testing, not the first-line investigation.
• C. CA-125 is a tumor marker used in ovarian malignancy evaluation, not a diagnostic test for ectopic pregnancy.

This patient has eclampsia, defined as a new seizure in a woman with preeclampsia (hypertension and proteinuria after 20 weeks gestation). Magnesium sulfate is the first-line anticonvulsant for both treatment and prevention of recurrent seizures in eclampsia, typically given as a loading dose followed by a continuous maintenance infusion, with proven superiority over phenytoin and benzodiazepines in reducing recurrent seizures and maternal mortality. Magnesium acts partly by antagonizing calcium at the neuromuscular junction and reducing cerebral vasospasm. Blood pressure control and planning for delivery are essential concurrent steps, but magnesium sulfate is the specific seizure prophylaxis and treatment of choice.

• A. Phenytoin was historically used but has been shown in randomized trials to be less effective than magnesium sulfate for eclamptic seizure control.
• C. Levetiracetam is not a standard first-line agent for eclampsia and lacks the evidence base supporting magnesium sulfate in this setting.
• D. Benzodiazepines may terminate an active seizure acutely in some protocols but are not the first-line agent for eclampsia and do not prevent recurrence as effectively as magnesium sulfate.

Flail chest is frequently associated with underlying pulmonary contusion, which may not be apparent on the initial chest X-ray and typically worsens over 24-72 hours due to alveolar hemorrhage and edema. This leads to progressive hypoxia, increased work of breathing, and risk of respiratory failure, so serial oxygenation assessment and monitoring are essential. Management includes adequate analgesia, oxygen therapy, and ventilatory support if hypoxia progresses. Pulmonary contusion is the leading cause of mortality in flail chest rather than the rib fractures themselves.

• A. Nonunion is a long-term orthopedic issue, not an acute life-threatening complication to monitor for.
• C. Splenic rupture is a left-sided abdominal injury concern, not directly related to this right-sided chest wall injury.
• D. Diaphragmatic rupture is more typical of penetrating trauma or severe blunt abdominal trauma, not the key concern here.

This patient has clinical features of acute compartment syndrome: disproportionate pain, pain on passive stretch of muscles within the compartment, and a tense swollen limb, despite preserved distal pulses, which are often normal until late. Compartment syndrome is a clinical diagnosis in a classic presentation, and intracompartmental pressure measurement is reserved for equivocal cases. Emergency fasciotomy is the definitive treatment and should not be delayed, as irreversible muscle and nerve necrosis can occur within 6-8 hours. Waiting for imaging or escalating analgesia risks permanent limb damage.

• A. Masking pain with analgesia without decompression allows ongoing tissue ischemia and necrosis.
• C. MRI is not used to diagnose compartment syndrome and would waste critical time.
• D. Delaying definitive treatment for repeat observation risks irreversible muscle necrosis.

Intravenous thrombolysis with alteplase is indicated in acute ischemic stroke within 4.5 hours of symptom onset, provided hemorrhage has been excluded and there are no contraindications. An INR greater than 1.7 (or above the therapeutic range on anticoagulants) is an absolute contraindication due to markedly increased risk of intracranial hemorrhage. Her time window and glucose are both appropriate for thrombolysis. Blood pressure above 185/110 mmHg is a contraindication unless controlled first, but her reading of 168/94 mmHg does not exceed this threshold.

• B. This time window is within the eligible 4.5-hour period, so it is not a reason to withhold treatment.
• C. This glucose level is within the normal range and not a contraindication.
• D. This blood pressure is below the 185/110 mmHg threshold that would require control before thrombolysis.

A non-contrast CT scan of the head is the first-line imaging test in suspected acute stroke because it rapidly and reliably excludes intracranial hemorrhage, which is an absolute contraindication to thrombolysis. It is widely available, fast, and does not delay time-sensitive treatment decisions. MRI is more sensitive for early ischemic changes but is slower and less readily available in the acute setting, so it is not the initial test. Carotid imaging and lumbar puncture play no role in the immediate decision to thrombolyse.

• A. MRI is more time-consuming and less practical for the immediate exclusion of hemorrhage in the acute setting.
• B. Lumbar puncture is not indicated and could be dangerous if there is any mass effect or raised intracranial pressure.
• C. Carotid duplex assesses stenosis for secondary prevention, not the acute decision regarding thrombolysis.

Status epilepticus is managed in a stepwise fashion: first-line treatment is a benzodiazepine (such as intravenous lorazepam or diazepam), and if seizures persist after an adequate first dose, a second-line intravenous antiepileptic such as levetiracetam, phenytoin, or valproate should be given. A second dose of benzodiazepine is not recommended after one adequate dose has failed, as it increases the risk of respiratory depression without added benefit. Phenobarbital and general anesthesia are reserved for refractory status epilepticus, which is defined as seizures continuing despite benzodiazepine and a second-line agent. Timing matters: the sequential steps in this escalation are benzodiazepine, then second-line AED, then anesthesia if refractory.

• A. Repeating the benzodiazepine after an adequate dose has failed adds little benefit and raises the risk of respiratory depression.
• C. General anesthesia is reserved for status epilepticus refractory to benzodiazepines and second-line antiepileptic drugs.
• D. Phenobarbital is used later in refractory status epilepticus, not as the immediate next step after benzodiazepine failure.

Thunderclap headache raises strong suspicion for subarachnoid hemorrhage, and a non-contrast CT head is the best initial test, with high sensitivity when performed within the first 6 hours and still useful at 8 hours, though sensitivity declines with time. If the CT is negative but clinical suspicion remains, a lumbar puncture should be performed, ideally more than 6 hours after symptom onset, looking for xanthochromia, which indicates blood breakdown products and confirms subarachnoid hemorrhage even when CT is negative. CT angiography is used subsequently to identify an aneurysmal source once SAH is confirmed, not as the initial screening test.

• A. Lumbar puncture should follow a negative CT, not precede it, since CT is faster and avoids unnecessary LP if hemorrhage is evident.
• B. MRI is not the first-line test for suspected acute SAH, and CT angiography is not the appropriate next step if initial imaging is negative.
• C. CT angiography and digital subtraction angiography identify the aneurysmal source after SAH is diagnosed, not for the initial screening sequence.

In suspected bacterial meningitis with features suggesting raised intracranial pressure, such as papilledema, altered consciousness, or focal neurological signs, lumbar puncture is contraindicated until these are excluded or managed, because of the risk of cerebral herniation. However, antibiotics must never be delayed for imaging or lumbar puncture; empirical intravenous antibiotics (such as ceftriaxone, with vancomycin added per local resistance patterns) should be given immediately once blood cultures are drawn. Delay in antibiotic administration is directly associated with increased mortality in bacterial meningitis. CT head, if performed, should only be used to assess safety of LP, not to decide on antibiotic timing.

• A. While CT may be done later to assess safety of LP, it must not be used as a reason to delay empirical antibiotics.
• C. Dexamethasone is an adjunct and blood cultures should be drawn quickly, but antibiotics must be given immediately, not withheld pending culture results.
• D. Lumbar puncture should not be performed first in this patient given signs of raised intracranial pressure, and should never delay antibiotics regardless.