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Difficulty: MediumCardiovascular System

A 58-year-old man presents to the clinic with progressive abdominal swelling, lower extremity edema, and exertional fatigue over the past 4 months. He has a history of Hodgkin lymphoma, for which he received mantle field radiation therapy 20 years ago. He has no history of tobacco or alcohol use. Vital signs are within normal limits. Physical examination shows marked jugular venous distension; the jugular venous pressure paradoxically increases during inspiration. Lung fields are clear to auscultation bilaterally. Cardiac auscultation reveals a regular rhythm and a high-pitched, early diastolic sound at the left sternal border. The abdomen is distended with a positive fluid wave, and the liver edge is palpable 4 cm below the right costal margin. Bilateral lower extremities demonstrate 2+ pitting edema up to the knees. An electrocardiogram reveals low-voltage QRS complexes in the limb leads. Which of the following is the most likely primary mechanism underlying this patient's presentation?

  1. Decreased ventricular compliance due to a rigid pericardiumAnswer
  2. B
    Chronic hypoxemia leading to pulmonary arterial hypertension
  3. C
    Ischemic injury causing left ventricular systolic dysfunction
  4. D
    Extracellular deposition of misfolded proteins in the myocardium
  5. E
    Rapid accumulation of fluid in the pericardial space

Answer

Decreased ventricular compliance due to a rigid pericardium
The clinical presentation is classic for constrictive pericarditis. The patient exhibits signs of right-sided heart failure (ascites, hepatomegaly, lower extremity edema) without left-sided failure (clear lungs). Kussmaul sign (a paradoxical increase in jugular venous pressure during inspiration) and a pericardial knock (an early diastolic sound caused by the sudden cessation of ventricular filling) are pathognomonic. Mantle field radiation therapy for Hodgkin lymphoma is a well-known cause of radiation-induced fibrosis, which can lead to a rigid, noncompliant pericardium years or decades later. This rigid sac severely restricts diastolic filling, leading to decreased ventricular compliance.

Step-by-Step Solution

1
Analyze the patient's symptoms and physical exam findings.
The patient has signs of isolated right-sided heart failure (edema, ascites, hepatomegaly, jugular venous distension) with clear lungs.
Identifying the side of heart failure narrows the differential diagnosis to right heart pathologies, pulmonary vascular disease, or pericardial disease.
2
Identify specific pathognomonic physical exam and ECG findings.
The exam shows Kussmaul sign (paradoxical rise in JVP with inspiration) and a pericardial knock (high-pitched early diastolic sound). ECG shows low voltage.
These findings are highly specific for restricted diastolic filling caused by a pericardial abnormality.
3
Correlate the findings with the patient's past medical history.
The patient had mantle field radiation therapy for Hodgkin lymphoma 20 years ago, which strongly predisposes him to late-onset constrictive pericarditis.
Connecting the etiology (radiation) with the presentation (right heart failure + Kussmaul sign + knock) confirms the diagnosis.

Key Concept

Constrictive pericarditis is a potential late complication of mediastinal radiation therapy. It presents with signs of right-sided heart failure, Kussmaul sign, a pericardial knock, and low-voltage ECG due to a rigid, thickened pericardium restricting ventricular compliance.
Estimated Time:1m 30s
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Topics

Cardiovascular System

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