Table 1.

Prevalence of risk factors for BCS and PVT in the absence of underlying liver disease and proposed diagnostic work-up and specific management (see[4], [5], [6], [7]^,13,14).

Condition	Prevalence		Recommended work-up
	BCS	PVT
Myeloproliferative neoplasm	30–57%	21–25%	Systematic genetic testing of the V617F mutation of the JAK2 gene in all patients. If negative: - Genetic testing of the CALR gene if platelet count ≥200 ×109/L and/or spleen length ≥16 cm - Discuss next-generation sequencing - Discuss bone marrow biopsy
JAK2 V617F	28–45%	15–21%
CALR mutation	1–3%	1–2%
Inherited thrombophilic disorders			Genetic testing for prothrombin G202101A and Factor V Leiden mutationsProtein S activity Protein C activity Antithrombin activity Protein S, C and antithrombin activities should be assessed in the absence of VKAs. Cautious interpretation of impaired liver function
G20210A prothrombin gene mutation	12%	5%
Factor V Leiden mutation	4%	8%
Antithrombin deficiency	3%	5%
Protein C deficiency	2%	1%
Protein S deficiency	2%	2%
Acquired thrombophilic disorders
Antiphospholipid antibody syndrome	5%	5%	Lupus anticoagulant, anti-cardiolipin, and anti-beta2 glycoprotein 1 antibody testing Repeat testing after 12 weeks in case of positive testing
Paroxysmal nocturnal hemoglobinuria	10%	0-0.5%	Flow cytometry analysis
Behcet’s disease	1-2%	Uncommon	No specific testing, clinical diagnosis Suspect Behcet's disease if: male sex, Mediterranean origin IVC stenosis, genital/oral ulcers, deep vein thrombosis in other sites, arterial thrombosis
Coeliac disease	1.4%	0.7%	Anti-transglutaminase antibody +/- duodenal biopsies
Other systemic factors Auto-immune disease Inflammatory bowel disease Vasculitis Sarcoidosis Connective tissue disease CMV disease			Search clinical and/or laboratory features CMV IgM and CMV PCR (blood)
Hormonal factors Oral contraceptive or pregnancy	∼30%	∼20%	Clinical context Search for introduction/modification of oral contraception within 6 months before diagnosis
Local factors  Pancreatitis  Diverticulitis  Cholecystitis  Appendicitis  Intra-abdominal surgery  Hydatid cyst	0-3%	20 %	CT scan Colonoscopy
No identified factor	10-29%	15-40%

BCS, Budd-Chiari syndrome; CMV, cytomegalovirus; IVC, inferior vena cava; PVT, portal vein thrombosis; VKAs, vitamin K antagonists.