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Difficulty: MediumRheumatology and Immunology

A 52-year-old woman comes to the clinic due to a 4-month history of progressively worsening shortness of breath and fatigue. She has a 12-year history of limited cutaneous systemic sclerosis, which has primarily manifested as Raynaud phenomenon, sclerodactyly, and cutaneous telangiectasias. She does not have a cough, fever, orthopnea, or lower extremity swelling. Vital signs are within normal limits. On physical examination, the lungs are clear to auscultation bilaterally. Cardiac examination reveals a prominently loud pulmonic component of the second heart sound (P2) and a right ventricular heave. There are no murmurs or gallops. Pulmonary function testing reveals the following:

ParameterPatient Value
FEV182%82\% of predicted
FVC85%85\% of predicted
FEV1/FVC ratio80%80\%
DLCO40%40\% of predicted

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

  1. Transthoracic echocardiographyAnswer
  2. B
    High-resolution computed tomography of the chest
  3. C
    Administration of intravenous furosemide
  4. D
    Empiric initiation of broad-spectrum antibiotics
  5. E
    Measurement of serum thyroid-stimulating hormone

Answer

Transthoracic echocardiography is the most appropriate next step to screen for pulmonary arterial hypertension.
The correct answer is transthoracic echocardiography. This patient with limited cutaneous systemic sclerosis (CREST syndrome) presents with progressive dyspnea, fatigue, and physical exam findings of right heart strain (a loud pulmonic component of the second heart sound and a right ventricular heave). Furthermore, her pulmonary function tests (PFTs) demonstrate an isolated decrease in the diffusing capacity for carbon monoxide (DLCO) with preserved forced vital capacity (FVC). This clinical picture is highly suggestive of pulmonary arterial hypertension (PAH), which is a common and severe complication of limited cutaneous systemic sclerosis caused by intimal hyperplasia of the pulmonary arteries. Transthoracic echocardiography is the most appropriate initial noninvasive screening test for PAH to estimate pulmonary artery pressures and assess right ventricular function. If echocardiography indicates PAH, a right heart catheterization is required for a definitive diagnosis.

Step-by-Step Solution

1
Analyze the patient's underlying disease and clinical presentation.
The patient has limited cutaneous systemic sclerosis and presents with progressive dyspnea and signs of right heart strain (loud P2, right ventricular heave).
Identifying the clinical syndrome and its known associated complications is essential for formulating a focused differential diagnosis.
2
Interpret the pulmonary function tests (PFTs).
PFTs show normal spirometry (FVC > 80%80\%) but an isolated, significantly reduced diffusing capacity for carbon monoxide (DLCO).
PFTs help differentiate between the two major pulmonary complications of systemic sclerosis: interstitial lung disease (ILD) and pulmonary arterial hypertension (PAH).
3
Determine the most appropriate diagnostic evaluation based on the suspected etiology.
Transthoracic echocardiography should be ordered as the next step.
In a patient with suspected PAH, echocardiography is the initial screening test of choice to evaluate right ventricular pressures before proceeding to definitive right heart catheterization.

Key Concept

Patients with limited cutaneous systemic sclerosis are at high risk for pulmonary arterial hypertension (PAH), which presents with signs of right heart failure and an isolated reduction in DLCO on pulmonary function testing. Transthoracic echocardiography is the initial screening test of choice.
Estimated Time:1m 30s
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Topics

Rheumatology and Immunology

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