A 54-year-old woman presents to the outpatient clinic reporting a 4-month history of progr… — USMLE Step 3

A 54-year-old woman presents to the outpatient clinic reporting a 4-month history of progressively worsening shortness of breath with exertion. She also notes a sensation of pressure in her lower neck and intermittent hoarseness. She has no history of asthma, chronic obstructive pulmonary disease, or cardiovascular disease. Her body mass index is $28 \text{ kg/m}^2$ . Vital signs show a temperature of $37.0^\circ\text{C}$ ( $98.6^\circ\text{F}$ ), blood pressure of $128/82 \text{ mmHg}$ , heart rate of $78/\text{min}$ , and respiratory rate of $16/\text{min}$ . On examination, the patient is in no acute distress at rest. Palpation of the anterior neck reveals a firm, diffusely enlarged thyroid gland. However, the inferior margins of both thyroid lobes cannot be palpated. Cardiopulmonary auscultation reveals normal S1 and S2 with no murmurs, and clear breath sounds bilaterally. Which of the following provocative physical examination maneuvers is most likely to produce a finding that identifies the etiology of her dyspnea?

Bilateral elevation of the arms alongside the head for up to 60 secondsAnswer
B
Application of firm, sustained pressure over the mid-abdomen while observing the jugular veins
C
Auscultation of the lung apices while the patient repeatedly phonates the vowel 'E'
D
Inspection of the anterior neck while the patient hyperextends the cervical spine and swallows
E
Having the patient perform a forced exhalation against a closed glottis

Answer

Bilateral elevation of the arms alongside the head for up to 60 seconds

The correct answer is bilateral elevation of the arms alongside the head for up to 60 seconds (Pemberton's maneuver). This patient's clinical presentation of exertional dyspnea, hoarseness, and an enlarged thyroid with unpalpable inferior margins strongly suggests a substernal goiter. A substernal goiter extends inferiorly into the rigid space of the thoracic inlet. When a patient elevates both arms, the clavicles are drawn upward and inward, further narrowing the thoracic inlet. In the presence of a substernal mass, this "corks" the inlet, leading to acute compression of the trachea and jugular veins. The resulting facial plethora, cyanosis, jugular venous distention, and potential stridor constitute a positive Pemberton's sign, which directly identifies the structural etiology of her dyspnea.

Step-by-Step Solution

Analyze the patient's presenting symptoms and physical exam findings.

The patient has exertional dyspnea, hoarseness, and an enlarged thyroid gland with unpalpable inferior poles.

Identifying the unpalpable inferior margin is the critical clue indicating that the goiter extends retrosternally (substernal goiter).

Determine the pathophysiological cause of the dyspnea.

The substernal extension of the goiter occupies space in the rigid thoracic inlet, compressing the trachea and causing dyspnea and hoarseness.

Structural compression of the airway by a large mass leads to exertional shortness of breath, independent of primary cardiopulmonary disease.

Identify the physical examination maneuver used to confirm this specific complication.

Pemberton's maneuver, which involves bilateral arm elevation, is the correct provocative test.

Raising the arms forces the clavicles into the thoracic inlet, further compressing the space. If a substernal goiter is present, this maneuver "corks" the inlet, compressing the jugular veins and trachea, producing a positive Pemberton's sign (facial plethora, cyanosis, and respiratory distress).

Key Concept

Pemberton's sign in substernal goiter

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