Medical Terminology for Portal Venous Air
The medical term for air in the portal veins of the liver is hepatic portal venous gas (HPVG) or portal venous gas.1, 2
Clinical Significance and Context
HPVG is a radiographic finding that represents gas within the portal venous system of the liver, historically associated with severe underlying abdominal pathology but increasingly recognized in benign conditions with improved imaging detection. 2, 3
Historical vs. Contemporary Understanding
Historically, HPVG was considered an ominous sign with mortality rates up to 75%, primarily associated with bowel necrosis and mesenteric ischemia requiring urgent surgical intervention.1, 4
Current evidence demonstrates that HPVG itself is not a surgical indication; rather, management depends entirely on the underlying disease process. 2, 3
The increased use of CT scanning and ultrasound has led to earlier detection and recognition of numerous benign, non-life-threatening causes of HPVG.2, 3
Common Underlying Causes
The most frequent conditions associated with HPVG include:
- Bowel necrosis/mesenteric ischemia (43% of cases) - the most serious cause requiring urgent surgical evaluation 4
- Digestive tract dilatation (12%) 4
- Intra-abdominal abscesses (11%) 4
- Inflammatory bowel disease (ulcerative colitis 4%, Crohn disease 4%) 1, 4
- Complications following endoscopic procedures (4%) 1, 4
- Enteritis and cholangitis 3
Diagnostic Imaging Findings
HPVG is typically identified through:
- CT scan (most sensitive and specific) - shows branching lucencies extending to the liver periphery 5, 2
- Plain abdominal radiography 2
- Doppler ultrasound 2
On CT imaging, HPVG appears as pneumatosis (gas within the bowel wall) and portal venous gas, which are frequently observed together in patients requiring intestinal resection. 5
Critical Management Principles
The presence of HPVG alone does not mandate exploratory laparotomy; surgical intervention is only indicated when intestinal ischemia or infarction is suspected based on combined radiologic and clinical findings. 3, 6
Key clinical indicators suggesting need for surgical intervention include:
- Persistent severe abdominal pain despite treatment 5
- Organ failure (shock, renal failure, metabolic acidosis) 5
- Elevated arterial lactates 5
- Massive ascites 5
- Rectal bleeding 5
- Peritoneal signs on physical examination 3
In patients without these concerning features, conservative management with antibiotics and treatment of the underlying condition is appropriate and often successful. 1, 3
Prognosis
- Overall mortality in contemporary series is approximately 39%, significantly improved from historical rates 4
- Prognosis is determined by the underlying pathology, not by the presence of HPVG itself 2
- Mortality varies dramatically: 100% in surgical candidates managed conservatively versus 12.5% in appropriate conservative management candidates 6
- Higher APACHE II scores predict mortality in both surgical and non-surgical management groups 6