🔍 Question

A 47-year-old woman presents with worsening shortness of breath on exertion and fatigue. She also experiences painful bluish discoloration of her fingers and toes during cold exposure, which resolves with warming. Her medical history includes severe gastroesophageal reflux disease. On examination, she has tight skin over her fingers, a small oral aperture, and telangiectasias on her lips. Cardiac examination reveals a prominent second heart sound over the upper left sternal border. Lung auscultation shows normal breath sounds without crackles. The abdomen is soft with mild hepatomegaly, and bilateral pitting edema is noted in the lower extremities. A chest X-ray shows no abnormalities, and spirometry results are as follows:

• Forced vital capacity (FVC): Normal

• Forced expiratory volume in 1 second (FEV1): Normal

• FEV1/FVC ratio: Normal

What is the most likely explanation for her dyspnea?

• A. Chest wall restriction

• B. Lung interstitial fibrosis

• C. Pericardial constriction

• D. Pulmonary arteriolar narrowing

• E. Pulmonic valve stenosis

Correct Answer 🎯: D. Pulmonary Arterial Narrowing

Systemic Sclerosis (Scleroderma) → Pulmonary Arterial Hypertension (PAH)

🧠 Key Insight: PAH occurs due to pulmonary arteriolar narrowing, not lung interstitial disease in this case.

⚙️

🧠 Endothelial Injury (Systemic Sclerosis)

⬇

⚙ Vascular Remodeling

• ↑ Endothelin-1 (Vasoconstrictor)

• ⬇ Nitric Oxide (Vasodilator)

⬇

Pulmonary Arteriolar Narrowing 🔍

⬇

↑ Pulmonary Vascular Resistance (PVR)

⬇

Right Ventricular Pressure ↑ → Pulmonary Hypertension

⬇

🔍 Signs of Right Heart Failure

• Hepatomegaly ⚖ (venous congestion)

• Bilateral Edema

⬇

↑ S2 Intensity 🧠 (↑ Pulmonic Valve Closure Pressure)

⬇

Dyspnea: ↓ Cardiac Output → ↓ O2 Delivery

Symptoms Explained 🔧

• Dyspnea:

Pulmonary hypertension → ↑ RV pressure → ↓ Cardiac Output → ↓ Oxygen delivery to tissues → Dyspnea on exertion.

• Increased Intensity of S2 (ULSB):

Pulmonary hypertension → ↑ Pulmonary artery pressure → Accentuated Pulmonic Valve Closure (S2)

• Normal Spirometry:

No parenchymal lung fibrosis → FEV1, FVC, FEV1/FVC remain normal.

Think of pulmonary arterioles as a narrowing pipeline 🚰:

• ↑ Pressure (PVR ↑)

• The right heart pumps harder to overcome the narrowing ⚙.

• Over time → RV hypertrophy + failure → systemic congestion (hepatomegaly, edema).

How To Approach this Question? 🏗️

• Pulmonary hypertension explains intense S2, exertional dyspnea, and signs of right heart failure.

• Normal spirometry rules out parenchymal lung disease and chest wall restriction.

• Pulmonary arteriolar narrowing ⚙ in systemic sclerosis is the most likely cause.

⚖️ Explanation of Other Differentials

📝 Flashcards

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Dr. Shoaib Ahmad

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