Blood component therapy in neonatal hemostatic disorders

Surgical evacuation of neonatal intracranial hemorrhage due to vitamin K deficiency bleeding

OBJECT

Although the incidence of vitamin K deficiency bleeding (VKDB) in neonates has dramatically decreased in the developed world since the adoption of routine vitamin K prophylaxis, in developing countries the incidence is still high. Intracranial hemorrhage (ICH) is the most dangerous complication. Early recognition and management are important to decrease the mortality rate and neurological sequelae. The authors conducted a prospective study between January 2008 and June 2010. They included all full-term neonates referred to the Department of Neurosurgery at Mansoura University Children's Hospital with ICH complicating VKDB and necessitating surgical evacuation. The objective was to evaluate the clinical presentation, diagnosis, hospital course, and outcome of ICH in full-term neonates with VKDB after surgical evacuation.

METHODS

Thirty-two neonates with ICH due to VKDB were included. Diagnosis and classification of ICH were based on detailed history, physical examination, and the interpretation of CT or MR imaging studies. The diagnosis of VKDB was based on pretreatment coagulation studies (prothrombin time [PT] and partial thromboplastin time [PTT]), which are grossly abnormal, together with a normal platelet count and correction of coagulation results to normal after vitamin K administration.

RESULTS

The mean age (± SD) at onset of symptoms was 20.4 ± 4.9 days. Two neonates (6.25%) had early VKDB, 7 (21.9%) had classic VKDB, and 23 (71.9%) had late VKDB. The most common neurological manifestations included focal seizures, disturbed consciousness level, and tense anterior fontanel. The most common general manifestations included pallor, respiratory distress, and bleeding from other sites. Radiological findings varied from acute subdural hemorrhage (SDH) in 18 cases (56.3%), intracerebral hemorrhage in 10 (31.3%), and acute SDH with underlying intracerebral hemorrhage, intraventricular hemorrhage, and/or subarachnoid hemorrhage in 4 (12.5%). Before administration of vitamin K, the PT was 72.1 ± 45.0 seconds and the PTT was 112.4 ± 57.6 seconds. Six to 12 hours after administration of vitamin K, the PT was 14.6 ± 1.6 seconds and the PTT was 34.4 ± 1.0 seconds. All patients underwent surgery for evacuation of the ICH after correction of PT, prothrombin activity, and international normalized ratio. Evacuation of the ICH was done by either free or osteoblastic bone flap. Six patients (18.8%) died, and the other 26 patients had variable degrees of morbidity during the follow-up period (3-24 months).

CONCLUSIONS

Vitamin K deficiency bleeding, especially the late-onset form, is an important cause of neonatal ICH. In the present study, the most frequent form of ICH in neonates was SDH. Focal seizures, disturbed consciousness level, tense anterior fontanel, unexplained anemia, and respiratory distress were the major presenting signs. Despite early surgical evacuation, these cases are associated with high mortality rate and neurological disabilities. Vitamin K prophylaxis at birth may reduce these severe complications.

The evaluation and management of neonatal coagulation disorders

Neonatal hemostatic abnormalities can present diagnostic and therapeutic challenges to the physician. Developmental deficiencies and/or increases of certain coagulation proteins, coupled with acquired or genetic risk factors, can result in a hemorrhagic or thromboembolic emergency. The timely diagnosis of a congenital hemorrhagic or thrombotic disorder can avoid significant long-term sequelae. However, due to the lack of randomized clinical trials addressing the management of neonatal coagulation disorders, treatment strategies are usually empiric and not evidence-based. In this chapter, we will review the neonatal hemostatic system and will discuss the most common types of hemorrhagic and thrombotic disorders. Congenital and acquired risk factors for hemorrhagic and thromboembolic disorders will be presented, as well as current treatment options. Finally, suggested evaluations for neonates with either hemorrhagic or thromboembolic problems will be reviewed.

Neonatal thromboembolic emergencies

Thrombosis risk is multifactorial, with interaction of hereditary risk factors and acquired environmental and clinical conditions. Newborns are at particular risk for thrombotic emergencies secondary to the unique properties of their hemostatic system, influences of the maternal-fetal environment, and perinatal complications and interventions. Thrombotic complications range from arterial and venous catheter thrombosis to purpura fulminans. Prompt identification and appropriate management of thrombotic emergencies is critical in avoiding limb-, organ-, and life-threatening complications. Treatment strategies have been extrapolated from adult literature but clinical experience from small-scale neonatal studies has resulted in therapeutic guidelines, which should be individualized for each neonate, taking into consideration age and clinical status.

Venous thromboembolic events in pediatric patients. Diagnosis and management

Venous thromboembolism is a rapidly increasing secondary complication in children being treated for serious, life-threatening, primary diseases. Most current management guidelines and recommendations for imaging techniques have been extrapolated from the results of trials in adults. This may be less than optimal for children as there are important differences. The purpose of this article is to summarize the information on venous thromboembolism in children, and offer some guidelines for diagnosis, prophylaxis, and therapeutic intervention based on the best available evidence.

Guidelines for antithrombotic therapy in pediatric patients

Because of the relatively low incidence of TEs in children, the diagnostic and therapeutic approaches used are largely extrapolated from guidelines for adults. Features that differ in children compared with adults include underlying disorders, high incidence of CVL-related DVT in the upper venous system, and response to SH, warfarin, and thrombolytic agents. There is a paucity of information on the risk/benefit ratio of the therapeutic interventions and long-term outcome. Clinical trials are urgently needed to clarify optimal management for pediatric patients with TEs.

The relevance of developmental hemostasis to hemorrhagic disorders of newborns

The hemostatic system is a dynamic evolving process that is age-dependent. Components of the hemostatic system are synthesized in early fetal life and do not cross the placenta from mother to fetus. However, plasma concentrations of proteins involved in hemostasis significantly differ from adults. Physiological reference ranges are available for premature infants, full-term infants and children from ages 1 to 16 years. In the coagulation system, plasma concentrations of the vitamin K-dependent and contact factors are decreased at birth, whereas other factors such as fibrinogen, FV, FVIII, and FXIII are similar or increased compared with adults at birth. In the fibrinolytic system, plasma concentrations of plasminogen are decreased at birth, whereas tissue plasminogen activator and plasminogen activator inhibitor are increased. Clinically, the hemostatic system of the young is effective and healthy infants do not suffer from spontaneous hemorrhagic complications. However, infants are more vulnerable, compared with older patients, for bleeding in the presence of either congenital or acquired haemostatic defects. Severe congenital bleeding disorders, although rare, frequently present in the newborn period. The most common acquired causes of bleeding newborns include disseminated intravascular coagulation, vitamin K deficiency, and liver disease. A description of these disorders and treatment guidelines are provided.