Rare bleeding disorders in children: identification and primary care management

Quantitative Systems Pharmacology for Rare Disease Drug Development

Though hundreds of drugs have been approved by the US Food and Drug Administration (FDA) for treating various rare diseases, most rare diseases still lack FDA-approved therapeutics. To identify the opportunities for developing therapies for these diseases, the challenges of demonstrating the efficacy and safety of a drug for treating a rare disease are highlighted herein. Quantitative systems pharmacology (QSP) has increasingly been used to inform drug development; our analysis of QSP submissions received by FDA showed that there were 121 submissions as of 2022, for informing rare disease drug development across development phases and therapeutic areas. Examples of published models for inborn errors of metabolism, non-malignant hematological disorders, and hematological malignancies were briefly reviewed to shed light on use of QSP in drug discovery and development for rare diseases. Advances in biomedical research and computational technologies can potentially enable QSP simulation of the natural history of a rare disease in the context of its clinical presentation and genetic heterogeneity. With this function, QSP may be used to conduct in-silico trials to overcome some of the challenges in rare disease drug development. QSP may play an increasingly important role in facilitating development of safe and effective drugs for treating rare diseases with unmet medical needs.

VHrare study: Prevalence, clinical features and management of severe rare bleeding disorders in a large cohort

INTRODUCTION

Rare bleeding disorders (RBD) constitute 5% of total hereditary bleeding disorders, although the number could be higher, due to the presence of undiagnosed asymptomatic patients. The objective of this study was to analyze the prevalence and characteristics of patients with severe RBDs in our area.

MATERIAL AND METHODS

We analyzed the patients with RBD followed at a tertiary-level hospital between January 2014 and December 2021.

RESULTS

A total of 101 patients were analyzed, with a median age at diagnosis of 27.67 years (range 0-89), of which 52.47% were male. The most frequent RBD in our population was FVII deficiency. Regarding the diagnostic reason, the most frequent cause was a preoperative test and only 14.8% reported bleeding symptoms at the time of diagnosis. A genetic study was carried out in 63.36% of patients and the most frequent mutation type found was finding a missense mutation.

CONCLUSIONS

The distribution of RBDs in our centre is similar to the one reported in the literature. The majority of RBDs were diagnosed from a preoperative test and this allowed preventive treatment prior to invasive procedures to avoid bleeding complications. 83% of patients did not have a pathological bleeding phenotype according to ISTH-BAT.

The Vascular Endothelium and Coagulation: Homeostasis, Disease, and Treatment, with a Focus on the Von Willebrand Factor and Factors VIII and V

The vascular endothelium has several important functions, including hemostasis. The homeostasis of hemostasis is based on a fine balance between procoagulant and anticoagulant proteins and between fibrinolytic and antifibrinolytic ones. Coagulopathies are characterized by a mutation-induced alteration of the function of certain coagulation factors or by a disturbed balance between the mechanisms responsible for regulating coagulation. Homeostatic therapies consist in replacement and nonreplacement treatments or in the administration of antifibrinolytic agents. Rebalancing products reestablish hemostasis by inhibiting natural anticoagulant pathways. These agents include monoclonal antibodies, such as concizumab and marstacimab, which target the tissue factor pathway inhibitor; interfering RNA therapies, such as fitusiran, which targets antithrombin III; and protease inhibitors, such as serpinPC, which targets active protein C. In cases of thrombophilia (deficiency of protein C, protein S, or factor V Leiden), treatment may consist in direct oral anticoagulants, replacement therapy (plasma or recombinant ADAMTS13) in cases of a congenital deficiency of ADAMTS13, or immunomodulators (prednisone) if the thrombophilia is autoimmune. Monoclonal-antibody-based anti-vWF immunotherapy (caplacizumab) is used in the context of severe thrombophilia, regardless of the cause of the disorder. In cases of disseminated intravascular coagulation, the treatment of choice consists in administration of antifibrinolytics, all-trans-retinoic acid, and recombinant soluble human thrombomodulin.

How to use a coagulation screen

A coagulation screen is an important screening test when investigating a child who presents with easy bruising or bleeding. Interpretation of a coagulation screen can be challenging for clinicians. Evolution of the haemostasis system during childhood means normal ranges vary with age and needs to be interpreted alongside the clinical information. It is essential to consider preanalytical variables when interpreting a coagulation screen, and the reason for the investigation must always be considered. It is important that the sample is taken under optimal conditions, including sample technique, use of the correct bottle and prompt transport to the laboratory. An abnormal coagulation screen may indicate an underlying congenital bleeding disorder or an acquired bleeding disorder, or may be due to sampling error. Limitations of the coagulation screen are essential to be aware of, as some children with normal coagulation screen results may have bleeding disorders. Conversely, an abnormal coagulation screen does not always indicate a bleeding disorder.

Patient-reported outcomes in autosomal inherited bleeding disorders: A systematic literature review

Aim

Currently, it is unknown which patient‐reported outcomes are important for patients with autosomal inherited bleeding disorders. Therefore, the purpose of this study is to systematically review the available literature assessing patient‐reported outcomes and their measurement methods in autosomal inherited bleeding disorders.

Methods

The Embase, Medline ALL, Web of Science Core Collection, Cochrane Central Register of Controlled Trails and Google Scholar databases were searched from inception until 14 August 2020. Studies on patient‐reported outcomes in patients with von Willebrand disease, inherited platelet function disorders and coagulation factor deficiencies were included.

Results

Twenty‐one articles met the inclusion criteria. Three studies were assessed as having poor quality, and therefore a high risk of bias. Nineteen studies had fair quality rating. Different measurements methods were used, ranging from predefined to self‐developed questionnaires. The majority of included studies focused on von Willebrand disease. Patients with von Willebrand disease reported lower health‐related quality of life compared to the general population. Overall, this trend was especially visible in the following domains: vitality, physical and social functioning and pain. Women with inherited bleeding disorders scored lower on health‐related quality of life compared to men, especially women with heavy menstrual bleeding. Patients with joint bleeds or heavy menstrual bleeding reported an increased level of pain.

Conclusion

Patients with autosomal inherited bleeding disorders report lower health related quality of life, especially those with joint bleeds or heavy menstrual bleeding. Numerous measurement methods are used in patients with autosomal inherited bleeding disorders, highlighting the need for studies using established, standardized measurement methods.

Developmental hemostasis in the neonatal period

BACKGROUND

The hemostatic system is complex and evolves continuously since gestation and well into the adult years, in a process known as "developmental hemostasis."

DATA SOURCES

A comprehensive review was performed after an extensive literature search on PubMed/MEDLINE concerning developmental hemostasis during the neonatal period. Relevant cross references were also included.

RESULTS

Although part of a system, each component of the hemostatic system evolves differently, with many displaying both quantitative and qualitative age-related differences. This leads to drastic disparities between the coagulation system of neonates and both other children's and adults', while still maintaining a generally balanced and physiological hemostasis. The motives behind this process remain to be fully elucidated but may be, at least in part, related to non-hemostatic factors.

CONCLUSIONS

Knowledge regarding "developmental hemostasis" is essential for everyone caring for newborns or even children in general and in this review, we describe each hemostatic system component's neonatal characteristics and age-related progression as well as explore some of the possible physiological motives behind the process.

Rare Coagulation Factor Deficiencies (Factors VII, X, V, and II)

Although rare clotting factor deficiencies primarily referred to as rare bleeding disorders (RBD), including factors II, V, VII, and X, make up ∼5% of all inherited bleeding disorders worldwide, each of these clotting factors play a critical role in the coagulation cascade. Incomplete bleeding evaluation or misinterpretation of laboratory studies can result in delayed diagnoses that ultimately affect patient outcomes. Bleeding manifestations can range from mild to severe, but the most common are mucocutaneous bleeding. The ideal treatment in RBD is dedicated single-factor concentrates that can be used for acute bleeding events, surgical management, and prophylaxis.

Preventing Surgical and Postpartum Hemorrhage in an Active Duty Patient With an Undiagnosed Coagulopathy at a Military Treatment Facility

Factor VII (FVII) deficiency is a hereditary bleeding disorder that significantly increases the risk of hemorrhage during the intrapartum and postpartum periods as well as during surgery. Management often requires careful pre- and post-operative planning, a multi-disciplinary approach, and management at a tertiary center. Most cases in the literature utilized recombinant FVII for treatment. We present a case of a young active duty female who had an undiagnosed FVII deficiency that became apparent during her expedited delivery for fetal distress. Our patient was admitted for delivery while undergoing a work up for an abnormal coagulation panel. Given high suspicion for FVII deficiency, anticipated hemorrhage, and need for cesarean delivery, she was treated with blood products containing FVII. Two days after delivery her diagnosis was confirmed. Available literature discusses the management of known FVII deficiency in pregnancy; however, to the best of our knowledge, there are no cases of an unknown bleeding diathesis incidentally identified just before delivery and later diagnosed as FVII deficiency. This case highlights the appropriate management of an unknown coagulopathy, the significant challenges associated, and the incorporation of a multi-disciplinary team critical to reducing significant maternal morbidity.

Hemorrhagic Shock after Neonatal Circumcision: Severe Congenital Factor XIII Deficiency

A Caucasian male infant born full term via normal spontaneous vaginal delivery was given vitamin K after birth, circumcised on day of life (DOL) 1, and discharged from the nursery on DOL 2. At the time of circumcision, oozing from the surgical site was noted and initially resolved with silver nitrate. Over the next two days, he presented to local emergency rooms multiple times for recurrent bleeding, eventually developing hemorrhagic shock resulting in admission to the neonatal intensive care unit. After extensive work up, he was ultimately diagnosed with severe congenital factor XIII deficiency. Congenital factor XIII deficiency is a rare bleeding disorder characterized by normal prothrombin time (PT) and activated partial thromboplastin time (aPTT) coagulation labs on routine screening, and has a high risk of complications, such as spontaneous intracranial hemorrhage. Although uncommon, when caring for a child with bleeding, physicians must have a high index of suspicion to make this diagnosis in order to initiate proper treatment and start prophylaxis given the risk of morbidity and mortality in untreated patients.

An overview of the potential sources of diagnostic errors in (classic) thromboelastography curve interpretation and preventive measures

Thromboelastography (TEG), a hemostatic point-of-care assay, provides global information about fibrin formation, platelet activation, and clot retraction in real-time. As it is an operator-dependent technique, error in any phase of the testing process can result in the misinterpretation of the thromboelastogram, and subsequently lead to mismanagement of the patient, wastage of blood products besides increasing the financial burden on the hospital and the patient. The present paper describes the possible errors leading to wrong thromboelastogram interpretation, and the respective preventive measure. In the light of limited resources available for operational challenges in TEG, this review paper can prove to be helpful.

A retrospective study on clinical manifestations of neonates with FXIII-A deficiency

We assessed clinical presentations and the rate of central nervous system (CNS) bleeding in neonates with FXIIID who exhibited bleeding diathesis in the early days of their lives. A total of 27 neonates presented bleeding or abnormal clinical symptoms, diagnosed with FXIII deficiency were evaluated. Factor XIII concentrate was initiated as the first-line of treatment, and prophylactic therapy was given to all patients. Umbilical cord bleeding, delayed detachment of umbilical stunt, seizure, hematoma, and ecchymosis were concurrent complications in 27 (100%), 5 (18.5%), 5 (18.5%), 3 (11.1%), and 1 (3.7%) of the patients, respectively. History of having CNS bleeding was detected in 13 (48.1%) patients. There was no significant association between CNS bleeding and gender, familial history of FXIIID, or other clinical presentations. Also, there was no significant difference in the mean age of the patients who had CNS bleeding (3.4 ± 0.9 days) and without CNS bleeding (2.9 ± 0.7 days). However, a near significant threshold difference between the patients with and without CNS bleeding was found regarding the mean number of suspicious FXIIID death in their family (1.8 ± 0.5 and 0.7 ± 0.1, respectively, P = 0.05). Therefore, a suggested diagnostic algorithm based on prenatal diagnosis could be useful for timely detection of FXIII deficiency in neonates.

Disorders of the Umbilical Cord

The umbilical cord, a vital conduit between the placenta and the fetus, loses much of its significance after birth. However, newborns can often present with various abnormalities of the umbilicus, such as benign granulomas or more serious lesions due to persistent remnants, many of which can change the normal course of cord separation and may be associated with significant morbidities if left unrecognized and uncorrected. Although not uncommon, sanguineous drainage from the umbilical stump can be quite alarming to new parents. Parental counseling regarding normal umbilical cord changes, as well as abnormal findings, such as discharge and skin changes, are important for the recognition and timely treatment of potentially significant umbilical cord disorders.

Congenital Factor Deficiencies in Children: A Report of a Single-Center Experience

Congenital factor deficiencies (CFDs) refer to inherited deficiency of coagulation factors in the blood. A total of 481 patients with CFDs, who were diagnosed and followed at our Pediatric Hematology and Oncology Clinic between 1990 and 2015, were retrospectively evaluated. Of the 481 cases, 134 (27.8%) were hemophilia A, 38 (7.9%) were hemophilia B, 57 (11.8%) were von Willebrand disease (vWD), and 252 (52.3%) were rare bleeding disorders (RBDs). The median age of the patients at the time of diagnosis and at the time of the study was 4.1 years (range: 2 months to 20.4 years) and 13.4 years (range: 7 months to 31.3 years), respectively. The median duration of the follow-up time was 6.8 years (range: 2.5 months to 24.8 years). One hundred nineteen (47.2%) of 252 patients with RBDs were asymptomatic, 49 (41.1%) of whom diagnosed by family histories, 65 (54.6%) through preoperative laboratory studies, and 5 (4.2%) after prolonged bleeding during surgeries. Consanguinity rate for the RBDs was 47.2%. Prophylactic treatment was initiated in 80 patients, 58 of whom were hemophilia A, 7 were hemophilia B, 13 were RBDs, and 2 were vWD. Significant advances have been achieved during the past 2 decades in the treatment of patients with CFDs, particularly in patients with hemophilias. The rarity and clinical heterogeneity of RBDs lead to significant diagnostic challenges and improper management. In this regard, multinational collaborative efforts are needed with the hope that can improve the management of patients with RBDs.

Characterization of distinct coagulopathic phenotypes in injury: Pathway-specific drivers and implications for individualized treatment

BACKGROUND

International normalized ratio (INR) and partial thromboplastin time (PTT) are used interchangeably to diagnose acute traumatic coagulopathy but reflect disparate activation pathways. In this study, we identified injury/patient characteristics and coagulation factors that drive contact pathway, tissue factor pathway (TF), and common pathway dysfunction by examining injured patients with discordant coagulopathies. We hypothesized that patients with INR/PTT discordance reflect differing phenotypes representing contact versus tissue factor pathway perturbations and that characterization will provide targets to guide individualized resuscitation.

METHODS

Plasma samples were prospectively collected from 1,262 critically injured patients at a single Level I trauma center. Standard coagulation measures and an extensive panel of procoagulant and anticoagulant factors were assayed and analyzed with demographic and outcome data.

RESULTS

Fourteen percent of patients were coagulopathic on admission. Among these, 48% had abnormal INR and PTT (BOTH), 43% had isolated prolonged PTT (PTT-CONTACT), and 9% had isolated elevated INR (INR-TF). PTT-CONTACT and BOTH had lower Glasgow Coma Scale score than INR-TF (p < 0.001). INR-TF had decreased factor VII activity compared with PTT-CONTACT, whereas PTT-CONTACT had decreased factor VIII activity compared with INR-TF. All coagulopathic patients had factor V deficits, but activity was lowest in BOTH, suggesting an additive downstream effect of disordered activation pathways. Patients with PTT-CONTACT received half as much packed red blood cell and fresh frozen plasma as did the other groups (p < 0.001). Despite resuscitation, mortality was higher for coagulopathic patients; mortality was highest in BOTH and higher in PTT-CONTACT than in INR-TF (71%, 60%, 41%; p = 0.04).

CONCLUSIONS

Discordant phenotypes demonstrate differential factor deficiencies consistent with dysfunction of contact versus tissue factor pathways with additive effects from common pathway dysfunction. Recognition and treatment of pathway-specific factor deficiencies driving different coagulopathic phenotypes in injured patients may individualize resuscitation and improve outcomes.

LEVEL OF EVIDENCE

Prognostic/epidemiological study, level II.

Factor VII Deficiency: Clinical Phenotype, Genotype and Therapy

Factor VII deficiency is the most common among rare inherited autosomal recessive bleeding disorders, and is a chameleon disease due to the lack of a direct correlation between plasma levels of coagulation Factor VII and bleeding manifestations. Clinical phenotypes range from asymptomatic condition—even in homozygous subjects—to severe life-threatening bleedings (central nervous system, gastrointestinal bleeding). Prediction of bleeding risk is thus based on multiple parameters that challenge disease management. Spontaneous or surgical bleedings require accurate treatment schedules, and patients at high risk of severe hemorrhages may need prophylaxis from childhood onwards. The aim of the current review is to depict an updated summary of clinical phenotype, laboratory diagnosis, and treatment of inherited Factor VII deficiency.

Rare bleeding disorders-old diseases in the era of novel options for therapy

Rare diseases are defined as life-threatening or chronically debilitating diseases with a prevalence of less than one per 2000 according to the European Union or one per 1250 according to the USA. Congenital rare bleeding disorders RBD are reported in most populations, with incidence varying from 1 in 5000 (Hemophilia A), 1:30,000 (Hemophilia B) to much rarer (1:500,000 for FVII deficiency, 1-3 million for Prothrombin or FXIII deficiency). Acquired Hemophilia A is also a rare bleeding disorder with estimated frequency of 1 in million. Most RBDs are inherited as autosomal recessive (AR); however, heterozygous carriers with varying degrees of corresponding factor deficiency may render an unpredictable propensity for bleeding. In patients with bleeding symptoms, laboratory assessment and especially molecular techniques currently enable accurate diagnosis and may provide tools for prenatal and family counseling. Currently hemostasis control is mainly based upon replacement of the missing coagulation factors (unless presence of inhibitors renders it impossible), however future gene therapy and disruptive, non-replacement alternatives may be promising for patients with RBD.

Guidelines for the primary prevention of stroke: a statement for healthcare professionals from the American Heart Association/American Stroke Association

The aim of this updated statement is to provide comprehensive and timely evidence-based recommendations on the prevention of stroke among individuals who have not previously experienced a stroke or transient ischemic attack. Evidence-based recommendations are included for the control of risk factors, interventional approaches to atherosclerotic disease of the cervicocephalic circulation, and antithrombotic treatments for preventing thrombotic and thromboembolic stroke. Further recommendations are provided for genetic and pharmacogenetic testing and for the prevention of stroke in a variety of other specific circumstances, including sickle cell disease and patent foramen ovale.