What are the possible causes of splenic varices?

Causes of Splenic Varices

Splenic varices primarily develop due to splenic vein occlusion or thrombosis, leading to sinistral (left-sided) portal hypertension, which redirects blood flow through collateral vessels forming varices. 1, 2

Primary Causes of Splenic Varices

Pancreatic Disorders

• Pancreatic cancer - causing external compression or invasion of the splenic vein
• Chronic pancreatitis - leading to inflammation and fibrosis around the splenic vein
• Pancreatic pseudocysts - causing extrinsic compression of the splenic vein 1, 3

Thrombotic Conditions

• Thrombophilic disorders - causing hypercoagulable states that lead to splenic vein thrombosis
• Essential thrombocytosis - associated with increased risk of splenic vein thrombosis 4
• Myeloproliferative disorders - causing increased blood viscosity and thrombosis risk

Malignancies

• Lymphoma involving the spleen - causing compression or invasion of splenic vasculature 3
• Gastric cancer - with local invasion or compression of splenic vessels
• Renal cancer - with extension to splenic vasculature 3
• Hepatobiliary malignancies - affecting portal circulation 1

Other Vascular Conditions

• Portal vein thrombosis - affecting portal circulation and causing retrograde flow
• Idiopathic non-cirrhotic portal hypertension (INCPH) - characterized by portal hypertension without cirrhosis 1
• Cavernous transformation of the portal vein - leading to altered portal hemodynamics 1

Inflammatory Conditions

• Intra-abdominal infections - causing local inflammation and thrombophlebitis
• Behçet disease - associated with vasculitis affecting splenic vessels 1

Iatrogenic Causes

• Post-surgical complications - following abdominal surgeries
• Umbilical catheterization in neonates - leading to portal vein thrombosis 1

Pathophysiological Mechanism

When the splenic vein becomes occluded, blood from the spleen cannot flow through its normal route to the portal vein. Instead, blood is diverted through collateral vessels:

1. Blood flows retrogradely through short and posterior gastric veins and gastroepiploic veins 3
2. This leads to formation of varices, primarily in the gastric fundus (isolated gastric varices) 1, 3
3. The increased pressure in these collateral vessels can lead to their dilation and eventual rupture, causing gastrointestinal bleeding 1

Diagnostic Considerations

The American College of Radiology recommends:

• Contrast-enhanced CT or MRI to identify splenic vein occlusion/thrombosis
• Assessment of inflow and outflow patterns of varices
• Evaluation for presence of gastrorenal shunts
• Endoscopy to confirm gastric varices and assess bleeding risk 2

Clinical Significance

Splenic varices are clinically important because:

• They can cause significant upper gastrointestinal bleeding
• The 1-year incidence of variceal bleeding in patients with varices without previous bleeding history is approximately 12% 1
• Mortality from variceal bleeding remains high (12-22%) despite advances in treatment 1
• Rebleeding is frequent (up to 60% within 1 year) without appropriate treatment 1

Treatment Implications

Treatment options depend on the underlying cause:

• Splenic vein recanalization - first-line treatment when technically feasible 2
• Partial splenic embolization - reduces flow through varices by decreasing splenic volume 1, 2
• Splenectomy - historically standard treatment for sinistral portal hypertension 1, 2
• Chemotherapy - effective for splenic vein occlusion caused by chemotherapy-sensitive tumors like lymphoma 3

For chemotherapy-sensitive causes like lymphoma, addressing the underlying condition may resolve the splenic vein occlusion and associated varices without the need for invasive interventions 3.

Important Pitfalls to Avoid

• Endoscopic therapy alone for splenic vein occlusion has poor outcomes (40% success) compared to splenic interventions (100% success) 1, 2
• BRTO (Balloon-occluded Retrograde Transvenous Obliteration) may increase risk of esophageal variceal hemorrhage 2
• Splenectomy in patients with inferior mesenteric vein draining into the splenic vein may lead to portal vein thrombosis 1, 2

Understanding the underlying cause of splenic varices is crucial for selecting the appropriate treatment strategy and preventing recurrent bleeding episodes.