DESCRIPTION

Pathologic arterial or venous intravascular occlusion secondary to abnormal thrombus formation; the following are common thrombotic events:

• Deep venous thrombosis (DVT): involves large systemic veins outside the central nervous system (CNS)
• Cerebral sinovenous thrombosis (CSVT): involves intracranial venous sinuses
• Ischemic stroke: CNS arterial occlusion with infarction of brain tissue
• Intracardiac thrombosis: mural, valvular, or foreign body associated
• Femoral artery thrombosis: can be associated with vessel catheterization
• Renal vein thrombosis: commonly in the neonatal period; may be unilateral or bilateral
• Myocardial infarction: Kawasaki disease, antiphospholipid antibody syndrome, or with severe familial hypercholesterolemia
• Budd-Chiari syndrome: thrombosis of the hepatic vein
• Portal vein thrombosis: most commonly seen in neonates with umbilical catheters

EPIDEMIOLOGY

• Age distribution is bimodal; peak rates are found in the neonatal and adolescent age groups.
• Idiopathic thrombosis is rare in children.
• >90% of pediatric venous thrombosis is associated with additional risk factors.
• Central venous lines are the most common risk factor for venous thrombosis in children.

RISK FACTORS

• Neonatal
  • Prematurity
  • Maternal diabetes
  • Umbilical catheters or other central lines
  • Sepsis
  • Polycythemia
  • Perinatal asphyxia
• Malignancy/bone marrow disorders
  • Leukemia (hyperleukocytosis and acute promyelocytic leukemia)
  • Myeloproliferative disorders (i.e., essential thrombocytosis and polycythemia vera)
  • Paroxysmal nocturnal hemoglobinuria
• Medications
  • Asparaginase (reduces antithrombin III)
  • Oral contraceptives (with estrogen)
  • Corticosteroids
• Anatomic
  • Indwelling catheters
  • Congenital heart disease
  • Prosthetic heart valves
  • Intracardiac baffles
  • Tumor compression
  • Atresia of the inferior vena cava
  • Thoracic outlet obstruction (Paget-von Schrötter syndrome)
  • May-Thurner syndrome (compression of the left iliac vein by the right iliac artery)
• Thrombophilia
  • Antiphospholipid antibody syndrome
  • Protein C and S deficiency
  • Antithrombin III deficiency
• Miscellaneous
  • Infection/inflammation
  • Obesity
  • Prolonged immobilization or paralysis (i.e., surgery and trauma)
  • Dehydration
• Risk factors/conditions specific for arterial disease
  • Kawasaki disease
  • Takayasu arteritis
  • Hyperlipidemia
  • Antiphospholipid syndrome
  • Lipoprotein lipase deficiency

COMMONLY ASSOCIATED CONDITIONS

• Nephrotic syndrome
• Inflammatory disorders (i.e., Crohn disease, sickle cell disease, and systemic erythematous lupus)
• Liver disease
• Diabetes mellitus
• Congenital heart disease (hypoplastic left heart syndrome)