An emergency medical services team brings a 72-year-old man to the acute care clinic due t… — USMLE Step 2 CK

An emergency medical services team brings a $72$ -year-old man to the acute care clinic due to a three-day history of escalating dyspnea and lower extremity swelling. He reports coughing up clear sputum and finds it difficult to lie flat at night. His past medical history includes chronic obstructive pulmonary disease (COPD), diet-controlled hypertension, and osteoarthritis. Current medications include inhaled tiotropium and as-needed albuterol.

His temperature is $37.0^\circ\text{C}$ ( $98.6^\circ\text{F}$ ), blood pressure is $156/92\text{ mm Hg}$ , pulse is $108/\text{min}$ , and respirations are $26/\text{min}$ . Pulse oximetry shows $87\%$ on room air. Physical examination reveals jugular venous distention up to $9\text{ cm H}_2\text{O}$ . Lung auscultation demonstrates bibasilar crackles extending to the mid-lung fields and prolonged expiration with scattered wheezes. Cardiac examination shows a regular, rapid rhythm with an audible S $_3$ gallop. There is $2+$ pitting edema in both lower extremities.

Laboratory results are as follows:

Test	Result	Reference Range
Leukocyte count	$8,400/\text{mm}^3$	$4,000-11,000/\text{mm}^3$
B-type natriuretic peptide (BNP)	$1,250\text{ pg/mL}$	$<100\text{ pg/mL}$
Thyroid-stimulating hormone (TSH)	$0.2\ \mu\text{U/mL}$	$0.4-4.0\ \mu\text{U/mL}$
Free thyroxine (T4)	$1.3\text{ ng/dL}$	$0.9-1.7\text{ ng/dL}$
Arterial pH	$7.30$	$7.35-7.45$
Arterial pCO $_2$	$60\text{ mm Hg}$	$35-45\text{ mm Hg}$
Arterial pO $_2$	$54\text{ mm Hg}$	$75-105\text{ mm Hg}$
Arterial HCO $_3^-$	$28\text{ mEq/L}$	$22-28\text{ mEq/L}$

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

Intravenous furosemide and supplemental oxygenCevap
B
Systemic corticosteroids and oral azithromycin
C
Intravenous piperacillin-tazobactam and isotonic saline bolus
D
Intravenous sodium bicarbonate infusion
E
Initiation of oral methimazole

Cevap

Intravenous furosemide and supplemental oxygen

The patient is experiencing acute decompensated heart failure (ADHF). Despite a history of COPD and the presence of wheezing, the key differentiating factors are the elevated jugular venous pressure, an S3 gallop, profound pitting edema, and a highly elevated BNP level. The wheezing in this context is known as 'cardiac asthma', caused by peribronchial edema. The mainstay of initial therapy for ADHF with volume overload is preload reduction, typically achieved with intravenous loop diuretics (e.g., furosemide) alongside supplemental oxygen or noninvasive positive pressure ventilation to correct hypoxemia.

Adım Adım Çözüm

Interpret the physical exam and diagnostic findings to establish the primary diagnosis.

The presence of jugular venous distention, an S3 gallop, bibasilar crackles, pitting edema, and a BNP of 1,250 pg/mL indicates acute decompensated heart failure (ADHF).

It is critical to differentiate ADHF from a COPD exacerbation. While the patient has COPD and wheezes, the cardiac findings and BNP firmly point to cardiac asthma and pulmonary edema.

Analyze the arterial blood gas and secondary laboratory findings.

The ABG reveals an acute-on-chronic respiratory acidosis (low pH, high pCO2, and mildly elevated bicarbonate). The thyroid panel shows euthyroid sick syndrome (low TSH, normal free T4).

Understanding the acid-base status ensures that treatments exacerbating acidosis (like bicarbonate) are avoided. Recognizing euthyroid sick syndrome prevents unnecessary antithyroid medications.

Select the most appropriate acute intervention for the primary diagnosis.

Intravenous furosemide and supplemental oxygen are selected.

Loop diuretics provide rapid preload reduction and diuresis, which relieves the pulmonary congestion driving the patient's respiratory failure.

Anahtar Kavram

Diagnosis and acute management of acute decompensated heart failure (ADHF) presenting with cardiac asthma in a patient with comorbid COPD.

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Cevap

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