Portal Hypertension Flashcards
What is the definition of portal hypertension (PHT) in pediatric patients?
There is no formal definition for pediatric PHT, but a porto-mesenteric pressure above 10 mmHg is arbitrarily used as the cut-off.
What are the three main causes of portal hypertension?
The three main causes are:
1. Portal vein obstruction (PVO) - usually synonymous with thrombosis.
2. Liver cirrhosis.
3. Liver fibrosis.
How can the causes of portal hypertension be categorized?
They can be categorized into:
1. Prehepatic (or presinusoidal) - e.g., portal vein obstruction.
2. Hepatic (or sinusoidal) - e.g., liver cirrhosis and fibrosis.
3. Posthepatic (or postsinusoidal) - related to issues beyond the liver.
Is the cause of portal hypertension always identified in children?
No, in many children, the cause is never found, even after detailed history and special investigations.
Why is identifying a reversible cause of portal hypertension important?
Identifying a reversible cause is crucial as it may impact the management and influence the feasibility of surgical correction, especially in cases of portal vein obstruction.
What are the main clinical features of long-standing portal hypertension?
The main clinical features include:
1. Varices at portosystemic confluences (especially oesophagogastric initially, later haemorrhoidal).
2. Splenomegaly.
3. Retroperitoneal shunts may also develop.
Where do varices develop first in portal hypertension, and what follows later?
Varices initially develop at the oesophagogastric zone and, after a few years, become more prominent around the haemorrhoidal plexuses.
Can splenomegaly be the only presenting feature of portal hypertension?
Yes, splenomegaly with hypersplenism can be the presenting feature without varices. However, the inverse (varices without splenomegaly) is rarely true.
Is ascites a common finding in portal vein obstruction (PVO)?
No, obvious ascites is a very late sign and is dependent on liver involvement and cirrhosis, not just elevated portal vein pressure. Therefore, it is rarely clinically evident in PVO.
What subtle clinical features may be noted in children with portal hypertension?
Growth faltering and poor scholastic performance may be observed, although the precise mechanism is unclear. These symptoms often improve when PVO is treated, such as with a physiological shunt (e.g., Meso-Rex Shunt).
What are the most important and clinically relevant consequences of portal hypertension?
Apart from splenomegaly, oesophageal and gastric varices are the most significant consequences due to their propensity to bleed, making them life-threatening.
What are oesophageal varices, and where do they develop?
Oesophageal varices are dilated veins within the lamina propria of the lower oesophagus. They develop from a dilated venous plexus and are most prominent in the distal 3–5 cm of the oesophagus.
What is the main contributing vessel to oesophageal varices?
The left gastric vein is the main contributor, draining through perforating veins into the azygos venous system.
How are the dilated veins arranged within the lower oesophagus
The veins are arranged as thin-walled, parallel vessels that run within the mucosal folds in a longitudinal manner.
Why are oesophageal varices easily visible during endoscopy?
When dilated, these superficial veins lie close to the mucosal surface, making them easily visible during endoscopy.
Where does most bleeding from oesophageal varices occur?
Most bleeding occurs within the distal 3–5 cm of the oesophagus, where the veins are superficial and prone to rupture.
What are the two main categories of gastric varices?
Gastric varices are categorized as Gastroesophageal varices and Isolated varices.
What are the two types of gastroesophageal varices?
- Type 1: Lesser curve varices (75%) extending to the oesophago-gastric junction.
- Type 2: Greater curvature varices, meeting the upper end of the cardia and draining into the left gastric and short gastric veins.
What are the two types of isolated gastric varices?
- Type 1: Fundal varices, with a high (78%) incidence of bleeding.
- Type 2: Varices located in the distal stomach or proximal duodenum.
Which type of isolated gastric varices has the highest risk of bleeding?
Type 1 isolated varices (fundal varices) have a high incidence of bleeding (78%).
What is portal biliopathy?
Portal biliopathy is jaundice caused by varices around the biliary tract, leading to congestion and biliary obstruction in the context of portal hypertension (PHT).
Is jaundice a common feature of portal hypertension in children?
No, jaundice is not usually a feature of PHT in children unless portal biliopathy develops.
What is portal hypertensive gastropathy?
Portal hypertensive gastropathy is a condition where the gastric mucosa appears as a fine, mottled punctate rash on endoscopy. As it worsens, it takes on a “snakeskin” appearance due to mucosal oedema.
What are the clinical consequences of portal hypertensive gastropathy?
It can cause contact bleeding, leading to symptomatic gastrointestinal bleeding, anaemia, or even melaena.
How is portal hypertension often diagnosed?
It may go unnoticed until a “herald bleed” occurs, typically presenting as haematemesis. Alternatively, an incidental finding of an enlarged spleen can prompt diagnosis.
What are some predisposing factors for portal hypertension?
Predisposing factors include:
1. Postnatal placement of an Umbilical Vein Catheter (UVC).
2. Neonatal peritonitis.
3. Thrombophilic states.
What should be done when portal hypertension is suspected?
A thorough evaluation should be conducted to identify portal hypertension and its potential consequences.
What imaging modality is most useful to assess portal vein occlusion?
Ultrasound with Doppler is most useful to assess portal vein occlusion and the direction of flow in the portal and splenic veins.
What additional findings can ultrasound with Doppler reveal in portal hypertension?
Ultrasound can also detect:
1. Splenomegaly.
2. Presence and volume of ascites.
3. Portal vein cavernoma.
4. Venous collaterals along the splenic, lower oesophageal, and gastro-epiploic veins.
5. Hepatic parenchyma and venous drainage assessment.
What is the role of endoscopy in portal hypertension?
Flexible esophago-gastroscopy is used to:
1. Identify and grade oesophageal and gastro-oesophageal varices.
2. Assess the ano-rectum for haemorrhoidal varices if not previously examined.
What blood test can confirm hypersplenism in portal hypertension?
A full blood count showing a platelet count of less than 100,000 confirms hypersplenism.
Why are coagulation studies important in portal hypertension?
Coagulation studies (including Protein S, Protein C, and Antithrombin III levels) are important to identify hypercoagulable states, which may preclude corrective surgery.
How is the level of obstruction to portal vein flow determined?
The level of obstruction is determined by gathering information to categorize it as prehepatic, intrahepatic, or posthepatic
What is the most common cause of portal vein obstruction in children?
The most common cause is portal vein occlusion due to thrombus.
What are the two main scenarios to consider when managing portal hypertension?
- Acute variceal bleeds.
- Chronic obstruction itself.
What is the first-line pharmacological treatment for acute variceal bleeds?
The contemporary approach includes the immediate use of:
1. Octreotide - to reduce mesenteric venous flow.
2. Tranexamic acid - to promote clotting.
What supportive measures should be taken alongside pharmacological treatment in acute variceal bleeds?
General resuscitative measures (ABCDE of APLS) should be applied.
What device was historically used to control bleeding from oesophageal varices, and why is it less commonly used now?
The Sengstaken-Blakemore tube was used, but it is less common now because Octreotide is so efficacious.
What is the primary goal of managing chronic portal vein obstruction in children?
The primary goal is to either bypass the obstruction or prevent variceal bleeding if a bypass is not feasible.
What are the two types of bypass procedures used for chronic portal vein obstruction?
- Physiologic (meso-portal) bypass: Routes mesenteric blood past the obstruction into the intra-hepatic portal vein (e.g., Rex or Meso-Rex shunt).
- Non-physiologic (meso-systemic) bypass: Routes mesenteric blood to the systemic venous circulation, bypassing the liver.
Which type of bypass is preferred, and why?
The physiologic bypass (meso-portal) is preferred because it maintains normal blood flow through the liver, preserving hepatic function.
What is an option for managing variceal bleeding if a bypass is not possible or while awaiting liver transplantation?
Variceal obliteration can be performed using:
1. Endoscopic sclerotherapy.
2. Endoscopic band ligation.
When might liver transplantation be necessary in chronic portal vein obstruction?
Liver transplantation may be needed if there is significant liver disease or failure that cannot be managed with bypass or variceal obliteration.
What factors influence the long-term outcomes of portal hypertension treatment?
Long-term outcomes depend on:
1. The initial cause of portal hypertension.
2. Presence of liver disease or failure.
3. Whether a physiological bypass was achieved.
What follow-up care is essential for children treated for portal hypertension?
Life-long follow-up is essential to monitor for:
1. Recurrent bleeding.
2. Signs of liver disease or deterioration.
3. Shunt patency in those who underwent bypass surgery.
What are the three main aetiological categories of portal hypertension?
- Pre-hepatic
- Intra-hepatic
- Post-hepatic
The most common cause in children is extrahepatic portal vein obstruction due to thrombus.
What is often the presenting symptom of portal hypertension in children?
An acute variceal bleed is often the presenting symptom.
Why is clotting factor function usually preserved in children with portal hypertension?
Because most children with portal hypertension do not yet have liver disease, their clotting factors and function are preserved.
How is an acute variceal bleed managed?
- Fluid resuscitation.
- Pharmacologic support with Octreotide IV and Tranexamic Acid.
- Esophago-gastroscopy for diagnosis and potential therapeutic intervention after resuscitation.
What procedure is both diagnostic and therapeutic in cases of upper GIT bleeds?
Esophago-gastroscopy (with appropriate equipment).
How are refractory variceal bleeds treated?
They can be treated with upper GIT endoscopy.
What determines the definitive treatment approach for portal hypertension?
The anatomy of the occlusion and the intra-hepatic portal vein branches.
What is the preferred definitive treatment when feasible?
Diversion of mesenteric blood back into the portal circulation (physiologic bypass).
What is the only option for survival in some children with portal hypertension?
Liver transplantation.
What is essential for all children treated for portal hypertension, regardless of treatment approach?
Attentive and meticulous life-long follow-up to monitor for recurrent bleeding, liver disease, and shunt patency.
