Neonatal Portal Vein Thrombosis - Types, Symptoms, Complications and Treatment

Introduction:

Neonatal portal vein thrombosis is a thrombotic disease seen in newborn children. It is a complication of neonatal care and contributes to the morbidity and mortality of newborns. It was first reported in 1868 by Balfour and Stewart in patients with findings of variceal dilation ascites and enlarged spleen. In neonates, portal vein thrombosis is related to catheters. In addition, it is associated with various predisposing factors, such as umbilical cannulation, septicemia, neonatal omphalitis, and improper catheter location.

Various genetic factors are associated, affecting the anticoagulants resulting in the risk of portal vein thrombosis. Active protein C resistance and Leiden factor predispose genetic factors to increase neonatal portal vein thrombosis risk. The coagulation cascade's fibrinolytic pathway and plasma concentration vary in newborn children. The amount of procoagulant and fibrinolytic activity in newborns differs from adults. Severe bleeding from the abdomen and an enlarged spleen is seen. The diagnosis is confirmed by doppler ultrasonography, based on treating the underlying cause.

What Is Neonatal Portal Vein Thrombosis?

Neonatal portal vein thrombosis is the complete or partial obliteration or occlusion of the portal vein lumen by thrombus formation. The portal vein is the blood vessel that brings the blood from the liver to the intestine.

What Are the Types of Neonatal Portal Vein Thrombosis?

Following are the types of neonatal portal vein thrombosis:

According to Severity:

• Acute Portal Vein Thrombosis - Acute portal vein thrombosis is the sudden formation of the thrombus within the portal vein. It usually involves mesenteric and splenic veins.

• Chronic Portal Vein Thrombosis - Chronic portal vein thrombosis occurs when the obstruction of the portal vein is replaced by a network of hepatopetal collateral veins passing the thrombosed part of the vein. It is also known as portal cavernoma.

According to Obstruction:

• Complete Portal Vein Thrombosis - There is complete obstruction of the lumen of the portal vein by a thrombus due to complete obstruction of hepatofugal veins within the mesenteric and splenic vessels.

• Incomplete Portal Vein Thrombosis - There is partial obstruction of the lumen of the portal vein by a thrombus. There is the presence of residual hepatopetal flow.

According to Infection:

• Infected Portal Vein Thrombosis - Infection and local inflammation contribute as a risk factor for partial vein thrombosis. Infected and suppurative thrombosis of portal vein known as pylephlebitis. It is seen in conditions such as appendicitis, diverticulitis, and appendicitis.

• Non-Infected Portal Vein Thrombosis - Certain conditions such as obstructive jaundice and gallstone in a cystic duct cause portal vein thrombosis without infection.

According to Anatomic Location:

• Thrombosis is confined to the portal vein.

• Thrombosis extended to the sub mesenteric vein.

• Diffuse thrombosis in splanchnic vessels.

• Extensive splanchnic venous thrombosis.

What Are the Causes of Neonatal Portal Vein Thrombosis?

A blockage usually causes neonatal portal vein thrombosis in the portal vein. Due to blockage of the lumen, the blood flow is slow. The major cause of portal vein thrombosis in neonates is an umbilical stump infection at the navel. However, there are various other causes of portal vein thrombosis as listed below:

• Excess red blood cells are known as polycythemia.

• Umbilical vein catheterization.

• Cancer of the liver, kidney, adrenal gland, and pancreas.

• Injury.

• Cirrhosis.

• Blood disorder.

• Antithrombin deficiency.

• Antiphospholipid syndrome.

• Factor Leiden mutation.

• Nephrotic syndrome.

• Protein C deficiency.

• Protein S deficiency.

What Are the Clinical Features of Neonatal Portal Vein Thrombosis?

If portal vein thrombosis is acute, recanalization can reverse symptoms. However, if the symptoms do not resolve by five to seven days, it indicates the involvement of the mesenteric arch with complete loss of mesenteric flow. If the obstruction is partial, the child is asymptomatic.

Following are the clinical features of neonatal portal vein thrombosis:

• It is commonly seen in male children.

• Hematemesis is seen due to variceal bleeding.

• Abdominal pain is found due to the involvement of intestinal ischemia and mesenteric veins.

• Non-bloody diarrhea and severe colicky pain.

• Intra-abdominal infection.

• Intestinal infarction.

• Ascites with small volume.

• Splenomegaly.

• The blood may pass through the digestive tract resulting in the foul-smelling black, tarry stool.

What Are the Complications of Neonatal Portal Vein Thrombosis?

As the portal vein is narrowed, the pressure is increased in the portal vein causing portal hypertension. Portal hypertension causes enlargement of the spleen resulting in splenomegaly. The presence of dilated and twisted varicose veins in the esophagus results in esophageal varices. These veins bleed profusely, resulting in gastrointestinal bleeding. In addition, there is fluid accumulation in the abdomen resulting in ascites. The other complications are renal failure, acidosis, and respiratory failure. If left untreated, it may result in multiorgan failure, shock and death.

How Neonatal Portal Vein Thrombosis Diagnosed?

Following are the various diagnostic tests for neonatal portal vein thrombosis:

• Colour Doppler Ultrasonography - It helps to detect the echogenic lesion present in the lumen of the portal vein.

• Computed Tomography - Computed tomography helps identify secondary bowel and underlying complications such as intra-abdominal abscess and infection.

• Portal Angiography - It is indicated for proper visualization of the portal vein.

• Thromboelastography - It is the dynamic assessment of whole blood coagulation.

What Are the Treatment Plans for the Neonatal Portal Vein Thrombosis?

Following are the treatment plans for neonatal portal vein therapy:

• Anticoagulant Therapy - Anticoagulant therapy is indicated for dissolving blood clots to prevent obstruction. The tissue plasminogen activator is advised.

• Antihypertensive Drugs - Antihypertensive drugs such as beta-blockers and nitrates are given to reduce the pressure in portal veins.

• Octreotide - It is given intravenously to reduce the blood flow of the liver and abdomen. It prevents gastrointestinal bleeding.

• Band Ligation - Endoscopic band ligation helps in the prevention of variceal bleeding.

• Sclerotherapy - Sclerosing agents are administered to remove the obstruction from the clot and prevent variceal bleeding.

• Portosystemic Shunt - It is placed distal to the esophagus to prevent recurrent variceal bleeding.

Conclusion:

Portal venous thrombosis is a thromboembolic disease in children whose mortality rate is low, but the child suffers long-term morbidity. The blockage or narrowing of the portal vein by blood clots increases portal hypertension. In addition, liver lobe atrophy and hepatic necrosis are potentially severe complications of portal venous thrombosis. Therefore, treatment is based on preventing the blood clot and recanalizing the portal vein.