Overall Bottom Line
- Cirrhosis is the most common cause of portal hypertension.
- Causes of NCPH include hepatovenous or portomesenteric thrombosis, alcoholic hepatitis and sinusoidal obstruction syndrome.
- Atypical patterns of intrahepatic fibrosis associated with NCPH include schistosomiasis, sarcoidosis, congenital hepatic fibrosis and cystic fibrosis.
- Increasingly recognized causes of NCPH are OPV and NRH.
- Typically, hepatic synthetic function is normal and liver chemistry tests are only mildly deranged in the setting of NCPH.
Section 1: Background
Definition of disease
- NCPH is the clinical manifestation of portal hypertension, i.e. ascites, variceal bleeding, occurring in the absence of cirrhosis.
Disease classification
- NCPH may be related to vascular thrombosis and their associated causes pylephlebitis, arteriovenous fistula, alcoholic hepatitis and sinusoidal obstruction syndrome (veno-occlusive disease).
- In addition, NCPH may be due to atypical patterns of hepatic fibrosis as seen in schistosomiasis, sarcoidosis, congenital hepatic fibrosis and cystic fibrosis.
Incidence/prevalence
- The true incidence of NCPH is unknown but NRH and OPV are increasingly being recognized on liver biopsy.
- A recent FDA Advisory was issued regarding the use of certain HAART medications, specifically didanosine and the development of NCPH.
- PVT may occur in conjunction with a hypercoagulable state and spontaneously in a small percentage of patients with long-standing cirrhosis.
Etiology
- Dependent upon the cause of NCPH.
- Portal and mesenteric vein thrombosis as well as hepatic venous outflow obstruction or sinusoidal obstruction syndrome are most commonly related to hypercoagulable states, such as JAK2 V617F mutation.
- NRH may be secondary to medications, collagen vascular disease or myeloproliferative disorders while OPV is currently considered idiopathic.
Pathology/pathogenesis
- Portal hypertension in the absence of cirrhosis results from either vascular thrombosis or architectural distortion of the liver.
- NRH arises as a consequence of an altered intrahepatic blood flow whereas in OPV the main histopathological finding is either diminished or, in severe cases, obliterated portal vein branches.
Predictive/risk factors
Common Causes of Non-Cirrhotic Portal Hypertension
NRH
OPV
Idiopathic portal hypertension
Incomplete septal cirrhosis
Sinusoidal obstruction syndrome
Alcoholic hepatitis
BCS
Schistosomiasis
Sarcoidosis
PBC/PSC
Congenital hepatic fibrosis
Hepatic arterio-portal fistula/splanchnic arteriovenous fistula
Extrahepatic portal vein obstruction
Hereditary hemorrhagic telangiectasia (Osler–Weber–Rendu)
Splenic vein thrombosis
Massive splenomegaly
Right-sided heart failure/constrictive pericarditis
Pylephlebitis
Section 2: Prevention
- No interventions have been demonstrated to prevent the disease aside from the anti-coagulation in patients having hypercoagulable or myeloproliferative disorders.
Screening
- Appropriate radiologic studies are performed in patients manifesting clinically with portal hypertension.
- Liver biopsy should be performed in the absence of vascular thrombosis to rule out an intrinsic liver disease.
Primary prevention
- Anticoagulation when appropriate.
- Antibiotic treatment of pylephlebitis.
- Medical treatment of schistosomiasis and sarcoidosis.
Section 3: Diagnosis (Algorithm 29.1)
- Diagnosis based on needle liver biopsy is difficult; it is imperative for the clinician to alert the pathologist as to the presence of portal hypertension in the patient. Because some patients have overlapping features of these conditions, these entities should be considered as morphologic variants within the wide spectrum of NCPH, related to intrahepatic impediment to blood flow.
Differential diagnosis
| Differential diagnosis | Features |
|---|---|
| Cirrhosis | Typical histology, known etiology of intrinsic liver disease in the setting portal hypertension |
| Chronic liver disease | Significant fibrosis despite the absence of established cirrhosis, e.g. sarcoidosis |
| Vascular thrombosis | Typical radiographic findings in the presence or absence of intrinsic liver disease |
Typical presentation
- Patients present with clinical evidence of portal hypertension usually manifested by varices with or without bleeding or ascites. Hepatic synthetic function is typically well-preserved or normal and there may be only minimal if any abnormal liver tests.
- Patients may also present with thrombocytopenia in the absence of clinical portal hypertension with hematologic investigations identifying hypersplenism as its etiology.
Clinical diagnosis
History
- Ask if the patient has a history of other thrombotic events, malignancy or family history of hypercoagulability or liver disease. Careful inquiry regarding past and present medication use is necessary.
- Ascertaining whether any systemic disease is present such as cystic fibrosis is important. Arterio-portal fistulas can occur after liver interventions. Patients may have developed PVT as children due to omphalitis from catheter replacement. It is important to exclude all forms of liver disease that may lead to cirrhosis.
- OPV has been associated with vinyl chloride and arsenic poisoning and, more recently, along with NRH, has been implicated in the development of NCPH in HIV patients receiving didanosine.
- Congenital hepatic fibrosis can be seen in conjunction with Caroli syndrome (Figure 29.1). Pylephlebitis is an ascending infection of the portal venous system that can lead to PVT and liver abscess. There is typically bacteremia arising from a right-sided abdominal process, e.g., diverticulitis, appendicitis, Crohn’s disease-related abscess.
Physical examination
- Findings of portal hypertension such as ascites, splenomegaly or caput medusae may be seen. Patients with sinusoidal obstruction syndrome or hepatic venous outflow obstruction may have ascites and peripheral edema. Alcoholic hepatitis may manifest with jaundice and cutaneous stigmata of chronic liver disease.
- NCPH due to systemic disease may exhibit physical findings of those illnesses such as chronic lung disease in cystic fibrosis, or skin and eye disease in patients with sarcoidosis.
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