A 62-year-old man presents to the clinic with a 4-week history of increasing abdominal girth and lower extremity edema. He reports mild exertional dyspnea but denies chest pain, orthopnea, or alcohol use. His past medical history is significant for a prior myocardial infarction. Vital signs are within normal limits. Physical examination reveals jugular venous distention 9 cm above the sternal angle. The abdomen is distended with shifting dullness and a positive fluid wave. There is bilateral 2+ pitting edema to the knees.
Laboratory results and diagnostic paracentesis findings are as follows:
| Test | Result | Reference Range |
|---|---|---|
| Serum | ||
| Total protein | 6.5 g/dL | 6.0-8.3 g/dL |
| Albumin | 3.8 g/dL | 3.5-5.0 g/dL |
| Total bilirubin | 1.2 mg/dL | 0.1-1.2 mg/dL |
| AST | 35 U/L | 8-40 U/L |
| ALT | 40 U/L | 7-56 U/L |
| Ascitic Fluid | ||
| Appearance | Clear, yellow | Clear |
| Total protein | 3.2 g/dL | Varies |
| Albumin | 1.5 g/dL | Varies |
| WBC count | 150/mm³ (80% mononuclear) | < 500/mm³ |
Based on the interpretation of these laboratory findings, which of the following is the most likely underlying mechanism for this patient's ascites?
- Elevated right-sided central venous pressureCevap
- BHepatic architectural distortion with sinusoidal fibrosis
- CPeritoneal surface microvascular permeability increase
- DExtensive glomerular basement membrane protein loss
- EHepatic vein thrombosis
Cevap
The most likely underlying mechanism is elevated right-sided central venous pressure (cardiac ascites).
The correct answer identifies elevated right-sided central venous pressure (cardiac ascites) as the mechanism. The patient's serum-ascites albumin gradient (SAAG) is 2.3 g/dL (3.8 - 1.5). A SAAG ≥ 1.1 g/dL indicates portal hypertension. To further differentiate the cause of portal hypertension, the ascitic fluid total protein is evaluated. A value ≥ 2.5 g/dL, as seen in this patient (3.2 g/dL), indicates preserved synthetic function and high protein exudation characteristic of post-sinusoidal etiologies, primarily cardiac ascites (e.g., right heart failure, constrictive pericarditis). The physical finding of jugular venous distention definitively supports a cardiac origin.
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Anahtar Kavram
The differentiation of ascites etiology requires calculating the serum-ascites albumin gradient (SAAG) to identify portal hypertension (≥ 1.1 g/dL) and evaluating ascitic total protein to distinguish between hepatic (< 2.5 g/dL) and post-sinusoidal/cardiac (≥ 2.5 g/dL) causes.