A 65-year-old man is brought to the emergency department due to severe, sudden-onset short… — USMLE Step 2 CK

A 65-year-old man is brought to the emergency department due to severe, sudden-onset shortness of breath that awakened him from sleep. The patient has a history of essential hypertension, hyperlipidemia, type 2 diabetes mellitus, and a 35-pack-year history of smoking. Current medications include amlodipine, metformin, and atorvastatin.

Temperature is 37.1°C (98.8°F), blood pressure is 210/115 mmHg, heart rate is 115/min, and respiratory rate is 28/min. Pulse oximetry is 88% on room air.

Physical examination reveals an anxious, diaphoretic man in severe respiratory distress, utilizing accessory muscles of respiration. Lung auscultation reveals a prolonged expiratory phase with diffuse bilateral wheezing and scattered crackles in the lower lung fields. Cardiac examination shows a tachycardic, regular rhythm with a prominent S4 gallop and no murmurs. There is 1+ bilateral pitting edema of the lower extremities.

Arterial blood gas on room air shows:

Measurement	Value	Reference Range
pH	7.26	7.35 - 7.45
$PaCO_2$	58 mmHg	35 - 45 mmHg
$PaO_2$	55 mmHg	75 - 105 mmHg
$HCO_3^-$	25 mEq/L	22 - 28 mEq/L

Recent outpatient laboratory results from two days ago show:

Measurement	Value	Reference Range
Thyroid-stimulating hormone (TSH)	1.2 µU/mL	0.4 - 4.0 µU/mL
Free thyroxine (T4)	0.7 ng/dL	0.9 - 1.7 ng/dL

Chest radiograph demonstrates bilateral perihilar alveolar opacities, indistinct pulmonary vascular margins, and cephalization of the pulmonary veins. There is no focal lobar consolidation.

Which of the following is the most appropriate initial step in the management of this patient?

Intravenous nitroglycerin and noninvasive positive-pressure ventilationCevap
B
Nebulized albuterol, ipratropium, and intravenous methylprednisolone
C
Intravenous ceftriaxone, azithromycin, and supplemental oxygen
D
Intravenous sodium bicarbonate infusion and endotracheal intubation
E
Intravenous levothyroxine and passive rewarming

Cevap

Intravenous nitroglycerin and noninvasive positive-pressure ventilation

The patient is presenting with sympathetic crashing acute pulmonary edema (SCAPE), characterized by extreme sympathetic drive, severe vasoconstriction, and a rapid spike in afterload that overwhelms the left ventricle. This leads to flash pulmonary edema. The wheezing occurs due to peribronchial edema, often termed 'cardiac asthma'. The most appropriate initial step is aggressive afterload and preload reduction with intravenous nitroglycerin, combined with noninvasive positive-pressure ventilation (NIPPV). NIPPV serves dual purposes: it mechanically stents open fluid-filled alveoli to improve gas exchange (correcting the acute respiratory acidosis), and it increases intrathoracic pressure, which physiologically decreases both venous return (preload) and left ventricular transmural pressure (afterload).

Adım Adım Çözüm

Evaluate the patient's vital signs and acute respiratory presentation.

The patient exhibits severe hypertension (210/115 mmHg), tachycardia, tachypnea, and hypoxia.

Recognizing a hypertensive emergency is crucial to identifying the underlying cause of the respiratory failure.

Analyze the physical examination and imaging findings.

The presence of an S4 gallop, diffuse wheezing, crackles, and a chest radiograph showing perihilar opacities with cephalization confirms acute fluid overload.

This differentiates cardiogenic pulmonary edema ('cardiac asthma') from a primary airway obstruction like a COPD exacerbation.

Interpret the arterial blood gas results.

A pH of 7.26 and PaCO2 of 58 mmHg indicates an acute, uncompensated respiratory acidosis.

This confirms impending respiratory failure due to increased work of breathing, mandating immediate ventilatory support rather than metabolic buffering.

Interpret the outpatient thyroid laboratory results.

A low Free T4 with a normal TSH indicates euthyroid sick syndrome.

This rules out myxedema coma and prevents the dangerous administration of exogenous thyroid hormone during an acute cardiac event.

Determine the optimal therapeutic intervention.

Select aggressive afterload reduction (nitroglycerin) and positive pressure ventilation (NIPPV).

Nitroglycerin rapidly decreases left ventricular afterload and preload, while NIPPV improves alveolar gas exchange and further reduces cardiac work.

Anahtar Kavram

Sympathetic crashing acute pulmonary edema (SCAPE)

Soru

Cevap

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