Portal hypertension
| Portal hypertension | |
|---|---|
 |
|
| The portal vein and its tributaries | |
| Classification and external resources | |
| Specialty | Gastroenterology |
| ICD-10 | K76.6 |
| ICD-9-CM | 572.3 |
| DiseasesDB | 10388 |
| eMedicine | radio/570 med/1889 |
| MeSH | D006975 |
Portal hypertension is hypertension (high blood pressure) in the hepatic portal system, which are the portal vein and its branches, which drain from most of the intestines to the liver. Portal hypertension is defined as a hepatic venous pressure gradient equal to or greater than 6 mmHg.Cirrhosis (a form of chronic liver failure) is the most common cause of portal hypertension; other, less frequent causes are therefore grouped as non-cirrhotic portal hypertension. When it becomes severe enough to cause symptoms or complications, treatment may be given to decrease portal hypertension itself or to manage its complications.
Signs and symptoms of portal hypertension include:
The causes for portal hypertension are classified as originating in the portal venous system before it reaches the liver (prehepatic causes), within the liver (intrahepatic) or between the liver and the heart (post-hepatic). The most common causes is cirrhosis (chronic liver failure). Other causes include:
The pathophysiology of portal hypertension is indicated by increasing vascular resistance via different etiologies; additionally, stellate cells and myofibroblasts are activated. Increased endogenous vasodilators in turn promote more blood flow in the portal veins.
Nitric oxide is an endogenous vasodilator and it regulates intrahepatic vascular tone (it is produced from L-arginine). According to Maruyama, et al., in laboratory studies nitric oxide inhibition increases portal hypertension and hepatic response to norepinephrine is increased.
The diagnosis of portal hypertension can be done via HVPG (hepatic venous pressure gradient) measurement has been accepted as the gold standard for assessing the severity of portal hypertension. Portal hypertension is defined as HVPG greater than or equal to 5 mm Hg and is considered to be clinically significant when HVPG exceeds 10 to 12 mm Hg.
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