portal hypertension Flashcards
classification of causes of portal hypertension
prehepatic - blockage of the portal vein before the liver
hepatic
posthepatic
prehepatic causes of portal HTN
portal/splenic vein thrombosis
congenital atresia/stenosis
extrinsic compression - eg tumours
hepatic causes of portal hypertension
cirrhosis - commonest UK
granulomata - sarcoid
myeloproliferative diseases
fibropolycystic disease - congenital hepatic fibrosis
schistosomiasis - commonest cause worldwide
hepatic mets
chronic hepatitis
idiopathic
nodular (nodular regnerative hyperplasia, partial nodular transformation)
toxins - arsenic, vinyl chloride
posthepatic causes of portal hypertension
budd-chiari (hepatic vein obstruction)
CCF (RHF)
constrictive pericarditis
veno-occlusive disease
sclerosing hyaline necrosis
sx of portal HTN
abdo swelling
haematemesis, PR bleeding or melaena - bleeding varices
jaundice
Lethargy, irritability and changes in sleep pattern - suggest encephalopathy.
Increased abdominal girth, weight gain - suggest ascites.
Abdominal pain and fever - suggest spontaneous bacterial peritonitis.
Pulmonary involvement is common in patients with portal hypertension
signs of portal HTN
signs of underlying disease
splenomegaly - followed by signs of hypersplenism eg thrombocytopenia
signs from increased blood flow through portosystemic anastomoses
upper GI bleeding from portal hypertensive gastropathy, GI ulcers, or diffuse lower GI bleeding
encephalopathy
transudative ascites/oedema
venous hum heard over large upper abdo collaterals - loudest in inspiration
signs of liver failure
signs of portal HTN from increased blood flow through portosystemic anastomoses
through paraumbilical and epigastric veins = caput medusae
via rectal veins = haemorrhoidal or anorectal varices
via veins of the gastric fundis and distal 1/3 of oesophagus:
- oesophageal varicies = risk of life threatening oesophageal variceal bleeding - haematemesis
- gastric varices = melaena
impaired liver function (cirrhosis)
complications of portal HTN
varices (+- haemorrhage)
ascites =
- spontaneous bacterial peritonitis
- hepatorenal syndrome
- hepatic hydrothorax
portal hypertensive gastropathy - condition caused by cirrhosis or portal vein thrombosis -> gastrointestinal ulcers or diffuse lower GI bleeding
pul complications of portal HTN
- portopulmonary HTN - pul arterial HTN
- hepatopulmonary syndrome
cardiac cirrhosis
cirrhotic cardiomyopathy
liver failure
hepatic encephalopathy
definition of portal HTN
abnormally high pressure in the hepatic portal vein
hepatic venous pressure gradient >=6mmHg
>10mmHg is clinically significant
>12mmHg is associated with complications
causes of acute portal HTN
acute portal vein thrombosis
causes of chronic portal HTN
chronic thrombosis
cirrhosis
shistosomiasis
Ix for portal HTN
bloods
imaging
- US and doppler
- abdo CT (spiral CT) - portal vein thrombosis
- MRI
- elasticity measurement - velocity of elsatic wave via an intercostally placed transmitter - results correlate with live rstiffness and so with fibrosis
oesophagogastroduodenoscopy - assessment and treatment of oesophageal varices
portal HTN measurement - hepatic venous pressure gradient - moderately invasive
liver biopsy - help find underlying cause
vascular imaging
US results for portal HTN
on duplex US
- see cavernous transformation of portal vein - indicates chronic portal vein thrombosis
- increased blood flow through portosystemic anastomoses
- direction of flow
portal vein dilated to >12mm
splenomegaly
liver size
ascites
medical Mx of portal HTN
1st line - non-selective B blocker (propranol/nadolol)
- inhibits B2 adrenergic receptors in GIT = splanchnic vasoconstriction = reduced portal and collateral flow = reduced Portal HTN
- prevent variceal bleeding
carvedilol - non-selective B blocker with anti-alpha1-adrenergic effects
pulmonary basoactive drugs (epoprostenol) - routine for idiopathic pulmonary HTN
vasoactive drugs - terlipressin and octreotide - reduce portal venous pressure, assist control of acute variceal bleeding
nitrates - added to B blocker - reduce portal pressure and rates of variceal re-bleeding
surgical Mx of portal HTN
transjugular intrahepatic portosystemic shunt
surgical portosystemic shunt - major surgery, less likely to stenose than TIPS
- total portosystemic shunt
- selective portosystemic shunt
- partial portosystemic shunt
devascularisation procedure - gastro-oesophageal devascularisation, splenectomy, oesophageal transection
transjugular intraheptaic portosystemic shunt
- needle catheter inserted via the internal jugular vein
- -> passed along to hepatic vein
- -> pierced through the liver parenchyma to intrahepatic branch of the portal vein
- -> expandable metal stent is placed
- -> side-to-side portocaval shunt
assures blood drainage from the portal to the systemic system bypassing the liver = lowering portal pressure, prevent re-bleeding from varices or the formation of ascites
indication for transjugular intrahepatic portosystemic shunt (TIPS)
persistent, recurring or treatment resistant upper GI bleeding from portal HTN eg oesophageal varices/gastric varices
refractory ascites
acute thrombosis of portal vein
pts with hepatorenal syndrome who are not eligible for or who are awaiting liver transplantation
hepatic hydrothorax
hepatopulmonary syndrome
budd-chiari syndrome
CI of transjugular intrahepatic portosystemic shunt
pre-existing hepatic encephalopathy or cirrhosis - shunt = reduced hepatic elimination of ammonia and worsening of encephalopathy
HF
severe pul HTN >44mmHg
uncontrolled systemic infection or sepsis
hepatic cysts or tumours
cavernous transformation of the portal vein following thrombosis
total portosystemic shunt
portal vein completely shunted to vena cava = reduced portal pressure
selective portosystemic shunt
portal vein is partially shunted to the vena cava = reduced portal pressure
prevents varices but allows portal perfusion
aetiology of portal HTN from increased hepatic blood flow
increased splenic blood flow - eg massive splenomegaly
hepatoportal arteriovenous fistula
L sided (sinistral) portal HTN
rare - confined to the L side of the portal system
may present as belleding from gastric varices
due to pathology incolbing the splenic vein or the pancreas
things to look for in history of portal HTN
alcohol consumption
Blood transfusion, especially abroad; lifestyles that predispose to hepatitis B or hepatitis C.
Family history - eg, Wilson’s disease or hereditary haemochromatosis.
signs of liver failure - portal HTN
Jaundice, spider naevi, palmar erythema.
Confusion, liver flap and fetor hepaticus are signs of encephalopathy.
Signs of hyperdynamic circulation: bounding pulse, low blood pressure, warm peripheries.
Enlarged or small liver.
Gynaecomastia and testicular atrophy
blood results for portal HTN
LFT
UE
glucose
FBC
clotting screen
ix for liver disease if unknown cause:
- ferritin - haemochromatosis
- hepatitis serology
- autoAb
- alpha-1 antitrypsin
- ceruloplasmin - wilson’s
vascular imaging for portal HTN
site of the portal venous block can be demonstrated by examing the venous phase of a coeliac or superior mesenteric arteriogram, by splenic portography following injection of dye into splenic pulp, or by retrograde portography via hepatic vein
hepatic venography is helpful when hepatic vein block or idiopathic portal HTN is suspected
conservative Mx of portal HTN
salt restriction and diuretics
Mx of portal HTN
conservative
medical
TIPS
surgical
liver transplant - avoided in pts with portopulmonary HTN with severe pul HTN that is refractory to medical therapy
endoscopic procedures for portal HTN
endoscopy - detect and monitor oesophageal varices
endoscopic vein ligation - prevent bleeding of oesophageal varices
For gastric varices with acute bleeding, endoscopic variceal obturation with tissue adhesives (eg, cyanoacrylate) complications - mucosal ulceration, thromboembolism
complications of TIPS
hepatic encephalopathy and deteriorating liver function
stent may stenose
requires follow up and may require repeat procedures
Mx of rectal varices
common in pts with portal HTN - dont usually bleed
located at anorectal junction
if they bleed - treatment similar to upper gastrointestinal varices
hepatopulmonary syndrome
triad of hepatic dysfunction, hypoxaemia, extreme vasodilation in the form of intrapulmonary vascular dilations
prognosis of portal HTN
depends on underlying disease and complications
pathophysiology of portal HTN
increased vascular resistence in portal venous system
active process - liver damage activates stellate cells and myofibroblasts -> abnormal flow patterns
increased blood flow in portal veins, from splanchnic arteriolar vasodilation caused by excessive release of endogenous vasodilators
raised portal pressure opens up venous collaterals, connecting the portal and systemic venous systems
- gastro-oesophageal junction = varices
- anterior abdo wall - caput medusae, or where adhesions between abdo viscera and parietal peritoneum, or sites of stomas, or previous surgeyr
- anorectal junction
- veins from retroperitoneal viscera - communicate with systemic veins on posterior abdo wall
If individual tributaries of the portal vein are thrombosed, = local venous hypertension: splenic vein block = oesophageal and gastric varices
In Budd-Chiari syndrome (hepatic vein occlusion), collaterals open up within the liver; blood tends to be diverted through the caudate lobe whose short hepatic veins drain directly into the inferior vena cava.
Portosystemic venous anastomoses can cause encephalopathy, possibly due to various ‘toxins’ bypassing the liver’s ‘detoxification’ process.
circulatory disturbances in portal HTN
portal HTN and cirrhosis = hyperdynamic circulation with splanchnic vasodilation, increased cardiac output, arterial hypotension, hypervolaemia
salt and water retention, ascites and hyponatraemia
