Young Man With Non-hypertensive Ascites of Unexpected Cause: When Ockham's Razor Is Not Sufficient

Abstract

Ascites is defined as the accumulation of fluid in the peritoneal cavity, following an imbalance between production and reabsorption; it is detectable from 50 mL on ultrasound. Three mechanisms have been classically implicated, according to Starling's forces: an increase in the hydrostatic pressure gradient (increased portal venous pressure), a reduction in the oncotic pressure gradient (loss of total proteins, especially albumin), and an increase in peritoneal capillary permeability. This latter mechanism, plus the difference between lymph production and excretion (which favors the accumulation of exudate), explains some of the most notable causes of non-hypertensive ascites (according to the serum albumin in ascites gradient (SAAG)), including peritoneal carcinomatosis and tuberculosis. We present the case of a young man, originally from a tuberculosis endemic area, in whom the study of ascitic fluid guided the workup and the definitive diagnosis, which was unexpected for his age. Finally, a practical approach to non-hypertensive ascites is provided.

Keywords: ascites; cancer; peritoneal carcinomatosis; peritoneum; tuberculosis.

Figure 1. Simple and contrast abdomen and pelvis CT

A. Axial view: abundant free liquid in the peritoneal cavity, with a central bowel pattern (arrow); nodular aspect of the omentum, with no focal lesions, and an increase in its vascularization due to multiple tubular structures (arrowhead). Thickened peritoneum, with up to 0.75 cm in the periphery. B. Coronal view: abundant free liquid in the abdominal and pelvic cavity, with bowel loops in mesogastrium, some of which are laid out in a radiated manner, with mesenterial hypervascularization in the center zone and the right iliac fossa (arrow).

Figure 2. Ascitic fluid drained on diagnostic and therapeutic paracentesis

Figure 3. Biopsy of the superior rectum lesion, magnified 4x

Superficial sample of colonic mucosae. Small foci of 0.8 cm wide located on the lamina propria, constituted by cells with enlarged nuclei, moderate pleomorphism, irregular borders, prominent nucleoli, and some atypical mitotic figures (wide and clear eosinophilic cytoplasm). Cells are arranged in a solid pattern, and no glandular structure is put together.