Thrombosis in children

What causes thrombosis in children?

The following conditions are identified that contribute to the development of thrombosis in newborns:

• vascular wall abnormalities (e.g. delayed closure of the ductus arteriosus) and its damage (primarily by vascular catheters);
• disorders (slowing down) of blood flow (for example, during infections; severe hypoxia, acidosis);
• changes in the rheological properties of the blood (for example, with polycythemia; severe dehydration, hypoxia, congenital anticoagulant deficiency).

The most common causes of thrombosis in children:

• the presence of vascular catheters (arterial catheters are especially dangerous);
• polycythemia;
• hyperthrombocytosis (for example, in neonatal candidiasis);
• shock and severe course of bacterial and viral infections with secondary vasculitis;
• antiphospholipid syndrome in the mother;
• hyperuricemia.

The formation of thrombosis in children also occurs in a number of hereditary thrombophilic conditions:

• deficiency and/or defects of physiological anticoagulants (antithrombin III, proteins C and B, thrombomodulin, inhibitors of the extrinsic coagulation pathway, heparin cofactor II, plasminogen activator), excess of protein C inhibitor and/or inhibitor of the antithrombin III-heparin complex;
• deficiency and/or defects of procoagulants [factor V (Leiden), prothrombin, plasminogen, factor XII, prekallikrein, high molecular weight kininogen], as well as thrombogenic dysfibrinogenemia;
• platelet hyperaggregability.

Symptoms of thrombosis in children

Locus of obstruction	Symptoms
Veins:
Lower hollow	Edema and cyanosis of the legs, often associated with renal vein thrombosis
Upper hollow	Swelling of soft tissues of the head, neck, upper chest; chylothorax may occur
Renal	Unilateral or bilateral renomegaly; hematuria
Adrenal	Hemorrhagic necrosis of the adrenal glands often occurs with clinical manifestations of adrenal insufficiency.
Portal and hepatic	Usually there are no clinical symptoms in the acute phase
Arteries:
Aorta	Congestive (overload) heart failure: difference in systolic pressure between upper and lower extremities; decreased femoral pulse
Peripheral	No palpable pulse; change in skin color; drop in skin temperature
Cerebral	Apnea, generalized or focal seizures, changes in neurosonography
Pulmonary	Pulmonary hypertension
Coronary	Congestive heart failure; cardiogenic shock; typical ECG changes
Renal	Hypertension, anuria, acute renal failure
Mesenteric	Clinical features of necrotizing enterocolitis

Diagnosis of thrombosis in children

If thrombosis is suspected in a child, all diagnostic means are used to determine the location of the thrombus or exclude this pathology. Various options for ultrasound examination and contrast angiography are used.

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Treatment of thrombosis in children

Treatment of thrombosis in children, proposed by different authors, is quite contradictory, since in this case randomized studies and recommendations based on them from the standpoint of evidence-based medicine are practically impossible. First of all, it is necessary to correct high-risk factors for thrombosis. In case of polycythemia, bloodletting is performed (10-15 ml/kg) with replacement of the removed blood with coagulation factor VIII or isotonic sodium chloride solution, antiplatelet agents are prescribed (nicotinic acid or pentoxifylline, piracetam, aminophylline, dipyridamole, etc.). Vascular catheters are removed if possible. In case of superficial thrombi, the skin above them is lubricated with heparin ointment (INN: Sodium heparin + Benzocaine + Benzyl nicotinate). Special antithrombotic therapy is rarely used. Sodium heparin is most often used for its implementation.

Sodium heparin is an anticoagulant that enhances the effect of antithrombin III on factor Xa and thrombin. It is the drug of choice for visualized thrombi. A loading dose of 75-100 U/kg of body weight is administered intravenously as a bolus over 10 minutes, followed by maintenance doses of 28 U/kg/h. During heparin therapy, hemostasis monitoring is necessary. APTT (activated partial thromboplastin time) should be at the upper limit of normal values. In some cases, surgical removal of the thrombus or a body part or organ necrotic due to impaired blood supply is performed.