Bradycardia and hypoxaemia due to position-dependent hypoperfusion of the brain stem in a preterm infant.

UNLABELLED: The case is reported of a male baby with a decreased time average velocity of the basilar artery to 32%, measured by Doppler sonography in dextro-rotated head position. The decrease was due to a hypoplastic right vertebral artery with compression of the contralateral vertebral artery at the craniocervical junction during dextro-rotation of the head. This finding was more prominent in prone than in supine position. A decrease in oxygen saturation and heart rate to < 70% and 60 bpm, respectively, was monitored during dextro-rotation. The polysomnography also revealed postural-dependent bradycardia, decrease of the oxygen saturation, and rising carbon dioxide partial tension in prone position with dextro-rotation of the head. CONCLUSION: Hypoperfusion of the brain stem caused by postural changes leads to further clinically relevant changes. Therefore an association with an acute life-threatening event and sudden infant death syndrome is speculated.

Clinical experiences with low-molecular weight heparins in pediatric patients.

The courses of 79 children (2 weeks to 19 years old) treated with two different low-molecular weight heparins (LMWHs)--nadroparin (n=66) and enoxaparin (n=13)--were retrospectively analysed. In 62 patients, LMWHs were given for short-term prophylaxis (1-2 weeks) during immobilization after surgery or trauma. Thirteen children with thromboembolic events received long-term prophylaxis with LMWHs for 2-18 months--six after thrombolytic therapy and seven after therapy with unfractionated heparin (UFH). Because of thromboembolic events, four patients were initially treated with LMWHs. In all patients with short-term prophylaxis, no thrombosis occurred. After thrombolytic therapy, three children had no reocclusion, two had no thrombus apposition and one had complete recanalization. In the seven patients treated with LMWHs after UFH, four had no reocclusion, two had recanalization and one had reocclusion. In all patients receiving LMWHs for initial treatment of thrombosis, no thrombus apposition, but also no recanalization, occurred. For short-term prophylaxis, nadroparin was used independent of the body weight and without determination of anti-factor Xa (anti-FXa) activity. Long-term prophylaxis was given mainly as doses of 45-100 anti-FXa U/kg resulting in anti-FXa activities between 0.2 and 0.4 U/ml. For treatment of thrombosis, doses of 200-300 anti-FXa U/kg corresponded to 0.5-1.0 anti-FXa U/ml. Side effects--slight gastrointestinal bleeding and temporary reversible hair loss--were seen in two patients. In conclusion, LMWHs proved to be efficacious and safe especially in prophylaxis of thromboembolic events in children.

Thrombolytic therapy in children--clinical experiences with recombinant tissue-plasminogen activator.

For the improvement of thrombolytic therapy with recombinant tissue-plasminogen activator (rt-PA) in children, more clinical data are needed. We retrospectively analyzed the clinical course of 20 patients (age ranging from 1 day to 16 years) with venous thrombosis (n = 16), arterial thrombosis (n = 2), and purpura fulminans by meningococcosis (n = 2). The venous thromboses were localized in the iliac-femoral veins (n = 9), brachiocephalic-jugular-subclavian veins (n = 6), and the superior caval vein (n = 1). The arterial occlusions were localized in the abdominal aorta and in the left pulmonary artery. Central venous catheters were of pathogenetic importance in seven cases. The patients were treated with rt-PA for 3 hours to 13 days. The dose ranged between 0.2 and 0.5 mg/kg for the initial bolus and 1.0 to 2.0 mg/kg/d for the continuous infusion. Nineteen patients received simultaneously low-dose unfractionated heparin. Complete clot lysis was detected in 11 cases, a partial lysis in 1, and in 8 patients thrombolytic therapy was not successful. An episode of hematemesis in one patient represented the only serious side effect observed in our study. A systemic decrease in fibrinogen concentration was also rare. In conclusion, thrombolysis with rt-PA represents an effective and safe therapy for children at the dosage used.

Clinical importance of prothrombotic risk factors in pediatric patients with malignancy--impact of central venous lines.

UNLABELLED: To evaluate the role of inherited thrombophilia in the development of central venous line (CVL)-related thrombosis, the following parameters were determined in 77 pediatric-oncologic patients with CVL: activated protein C (APC)-ratio, factor V (FV) G1691A and prothrombin G20210A mutation, protein C, protein S, antithrombin, coagulation factor XII, lipoprotein (a) and homocysteine. An inherited prothrombotic risk factor was found in 17 patients (23%). Four out of 14 patients with a single detect (hyperlipoproteinemia, heterozygous FV G1691A and prothrombin G20210A mutation, protein C deficiency type I) and all three patients with combined defects (heterozygous FV G1691A mutation combined with heterozygous prothrombin G20210A variant, protein S deficiency or hyperlipoproteinemia) suffered from CVL-related thrombosis. In 11 out of 77 patients (14%) a CVL-related thrombosis was detected. In 2 children thrombosis occurred a few days after asparaginase therapy and in another three thrombosis was associated with CVL-related septicemia caused by Staphylococcus epidermidis. After removal of CVL, thrombosis was detected in 5 children, in 2 without clinical symptoms but in the presence of inherited prothrombotic risk factors. CONCLUSION: The present study demonstrates the clinical importance of CVL in combination with inherited thrombophilia in the development of thrombosis in pediatric-oncologic patients. Before or shortly after insertion of CVL, patients should be tested for the presence of factor V G1691A mutation, prothrombin G20210A variant and increased lipoprotein (a) values.