Laboratory issues in bleeding disorders

Hemorrhagic complications in individuals with liver disease submitted to minor oral surgery

Individuals with chronic liver disease (CLD) have an increased risk of bleeding from thrombocytopenia and changes in hemostasis. The aim of this study was to evaluate the frequency of and the factors associated with the occurrence of bleeding in CLD patients who underwent dental surgical procedures. This was a retrospective study whose data were collected in a hospital dentistry service between 2010 and 2016. The patients were referred from the gastroenterology and liver transplantation services of a university hospital for dental treatment. The study followed the STROBE guidelines. Among the 71 surgical procedures performed, there were 17 (24%) perioperative and postoperative bleeding episodes, 14 of which were in pretransplant patients and 11 received blood transfusion before dental surgery. Individuals with a previous history of bleeding (PR = 2.67, CI = 1.07-6.67, P = 0.035) and those with a platelet count before surgery 50 × 109/l or less (PR = 7.48, CI = 1.70-32.86, P = 0.008) had a higher prevalence of perioperative and postoperative bleeding episodes than their peers without a previous history of bleeding, and those with platelet count greater than 50 × 109/l. The approach to individuals with CLD is complex and represents a challenge to the clinician. A careful anamnesis combined with laboratory screening of coagulation disorders appears to be useful to identify individuals at a major risk of bleeding. Studies identifying the predisposing factors of bleeding in CLD patients support well tolerated protocols for oral surgery in this group.

[Step by step - A diagnostic approach to bleeding disorders]

The main symptom of hemorrhagic diathesis is an increased bleeding tendency. Due to the subjectivity of various features of the bleeding history, unclarity of the family history, and an individualization of the extent of diagnostic the evaluation of a suspected bleeding disorder represents a challenging endeavour in hematology. Hemorrhagic diathesis can be divided into the following sub-categories: disorders in primary hemostasis (e. g. von Willebrand disease, different causes of thrombocytopenia), secondary hemostasis (e. g. hemophilia A and B, Vitamin K deficiency) and fibrinolysis, and in connective tissue or vascular formation. This article reviews available diagnostic methods for bleeding disorders, from structured patient history to highly specialized laboratory diagnosis.

Management of large volume liposuction in lipedema patients with von Willebrand disease: A systematic review and treatment algorithm

BACKGROUND

When performing large volume liposuction, perioperative management of lipedema patients with coagulation disorders remains challenging due to a lack of clinical experience. With a prevalence of 1% of von Willebrand disease (VWD) in the general population, basic knowledge on diagnostic and adapted surgical strategies are essential for patients' safety.

OBJECTIVE

Based on a selective literature review, the purpose of this article is to present a standardized algorithm for diagnosis and perioperative treatment of VWD patients undergoing large volume liposuction.

METHODS

The databases MEDLINE (via PubMed) and Web of Science were selectively searched with the term "(((liposuction) OR (surgery)) OR (lipectomy)) AND (((VWD) OR (hemostaseology)) OR (von Willebrand disease))". Included were articles published in English or German until November 2020.

RESULTS

The evidence for large volume liposuctions in patients with VWD is limited. Experience is largely based on operations with similar bleeding risks. A safe performance requires an adjustment of the surgical technique and a customized perioperative drug substitution plan. According to the current literature, perioperative thromboembolic events appear to be rare with adequate drug treatment.

CONCLUSION

The implementation of the developed diagnostic and treatment algorithm may help further reducing bleeding complications and improve the safety for treated patients.

Anesthesia for ORL surgery in children

ORL procedures are the most common operations in children – an optimal anesthetic management provides an uncomplicated, safe perioperative process with as little discomfort for the child as possible. Children at risk must already be identified preoperatively: the combination of ORL surgery, airway susceptibility and age below 3 years can increase the risk of perioperative respiratory adverse events. Postoperatively, it is important to prevent complications such as pain and PONV by dedicated prevention and treatment strategies, as well as to recognize and treat respiratory or circulatory complications competently. Interdisciplinary guidelines and agreements as well as the overall competence of the team have the potential to improve patient safety and outcome in children.

Laboratory identification of factor inhibitors: an update

Coagulation factor inhibitors comprise antibodies that bind to and then neutralise specific pro-coagulant plasma proteins. Coagulation factor inhibitors can develop against any coagulation factor, although the most common are against factor VIII (FVIII). These can develop in individuals with inherited haemophilia A (HA) as an immune response to factor replacement therapy, or as auto-antibodies leading to the condition of acquired HA. Clinical suspicion for inhibitors may arise when individuals present with bleeding symptoms without any prior bleeding diathesis, or when a patient with known mild haemophilia presents with a bleeding diathesis more extreme to their usual presentation, or when there is failure of factor replacement therapy to arrest bleeding in a known haemophiliac. The laboratory identification of factor inhibitors requires a careful and systematic approach that excludes other possible causes of prolonged screening tests, most commonly the activated partial thromboplastin time (APTT), and sometimes prothrombin time (PT). Coagulation factor inhibitor studies, including the Bethesda assay, are then undertaken to measure inhibitor titre, which guides treatment. This paper overviews the laboratory investigation of factor inhibitors, and also briefly reviews recent cross-laboratory inhibitor studies and the most recent evidence related to differential inhibitor formation according to type of therapy.

Prospective evaluation of a pediatric bleeding questionnaire and the ISTH bleeding assessment tool in children and parents in routine clinical practice

BACKGROUND

Diagnosing mild bleeding disorders (BDs) in children is difficult. Bleeding scores (BSs) have been proposed for obtaining standardized quantitative histories.

OBJECTIVES

To compare the Canadian pediatric bleeding questionnaire (PBQ) with the new ISTH bleeding assessment tool (ISTH BAT) for the determination of BS in a routine pediatric outpatient setting.

METHODS

One hundred children with a suspected BD were enrolled in this cross-sectional study. Bleeding scores were calculated for all children and their natural parents. For all children, extensive laboratory investigations were performed.

RESULTS

Based on laboratory tests, 56 children were diagnosed as having no BD, 11 were diagnosed with possible VWD, 12 with VWD 1, 11 with VWD 2, five with possible platelet defects, and five with mild factor deficiencies. Both questionnaires were able to discriminate between no BD and VWD (P = 0.0001), but the area under the receiver characteristics curve to detect any mild BD was only 0.76. Despite the inherited nature of the BD, a family score did not increase the ability to discriminate between no BD and VWD (P = 0.2052). There was no significant difference between the two tools used (P = 0.3253) or simple qualitative criteria, such as yes/no questions regarding bleeding (P = 0.3477).

CONCLUSIONS

The two tools translated into German did not differ substantially. Both were able to discriminate between no BD and a possible BD with acceptable accuracy. A BS of < 2 makes a BD unlikely. Simple qualitative criteria were similar; however, to allow comparison of studies and follow-up in patients over time, we recommend the ISTH BAT.

Management of pregnancy and delivery in women with inherited bleeding disorders

Women with inherited bleeding disorders present a wide spectrum of clinical symptoms that vary from mild or moderate bleeding tendency to severe episodes. Monthly haemostatic changes affect these women during menstruation and ovulation. These events may be associated with significant bleeding and pain leading to the limitations in conducting daily activities and adverse effect on quality of life. Likewise, pregnancy and delivery are critical times for affected women. During pregnancy, they may be at greater risk of miscarriage and bleeding complications. In particular, recurrent miscarriage was observed in women with type 3 von Willebrand disease, afibrinogenaemia and severe factor XIII deficiency, and an optimal therapeutic plan is required during their pregnancy. Precautions must be taken at delivery in these women, since they could be at risk of bleeding. The lack of adequate information makes it very difficult to prepare evidence-based guidelines for the prevention of bleedings in affected women and their treatment. A multidisciplinary team of obstetricians, haematologists and paediatricians is required with a good knowledge of these disorders and an awareness of the potential maternal neonatal complications.

Significance of advanced haemostasis investigation in recurrent, severe post-tonsillectomy bleeding

Objective:

To evaluate the significance of advanced post-operative haemostasis investigation in cases of recurrent, severe post-tonsillectomy bleeding.

Materials and methods:

Of the 120 patients treated at our tertiary centre between 2006 and 2010 due to post-tonsillectomy haemorrhage, 22 with recurrent, severe episodes of bleeding underwent further, advanced haemostasis investigation.

Results:

Underlying haemorrhagic disease was not diagnosed in any case. Isolated abnormal clotting factor levels were identified in two patients. Decreased fibrinogen concentration due to dilutional coagulopathy was found in nine cases (40.9 per cent).

Conclusion:

Recurrent, severe post-tonsillectomy haemorrhage is rarely related to undiagnosed haemostatic disorders. Thus, advanced haemostasis studies have little therapeutic relevance. However, repetitive post-tonsillectomy bleeding may be related to decreased fibrinogen levels due to dilutional coagulopathy. Therefore, fibrinogen concentration should be tested, and dilutional coagulopathy treated promptly.

Quantitation of bleeding symptoms in children with von Willebrand disease: use of a standardized pediatric bleeding questionnaire

SUMMARY BACKGROUND

Excessive bruising and mucocutaneous bleeding are frequent presenting symptoms in childhood. A detailed bleeding history can distinguish children who may have an inherited bleeding disorder from those who are normal. There is a lack of standardization of such history taking in pediatric practise.

OBJECTIVES

To assess the performance of a Pediatric Bleeding Questionnaire (PBQ), an adaptation of a standardized adult bleeding questionnaire and score that includes pediatric-specific bleeding symptoms, in a cohort of children with von Willebrand disease (VWD).

PATIENTS/METHODS

Bleeding scores were determined by interview, for children with a previous diagnosis of VWD and a control group of unaffected siblings.

RESULTS

Bleeding scores were obtained for 100 children with VWD, median age 10.9 years (range, 0.8-17.8 years), and 21 unaffected siblings. Median bleeding score in children with VWD was 7.0 (range, 0-29) and in the control group was 0 (range, -1-2). Bleeding score varied within and between each VWD type: definite type 1, n = 40, median, 9.0 (range, 2-18); possible type 1, n = 38, median, 2.0 (0-15); type 2, n = 6, median, 14.0 (3-17); and type 3, n = 16, median, 12.0 (4-29). Bleeding scores in affected children correlated with age (Spearman's correlation coefficient, 0.35; P = 0.0004). The most frequent clinically significant bleeding symptoms were surgical bleeding, bleeding after tooth extraction and menorrhagia. Post-circumcision bleeding, cephalohematoma, macroscopic hematuria and umbilical stump bleeding were clinically significant in 32% (of circumcised males), 4%, 4% and 3% of children, respectively.

CONCLUSIONS

The PBQ provides a standardized quantitation of bleeding severity in children with VWD.

Hemostatic and hemorrhagic problems in neurosurgical patients

BACKGROUND

Abnormalities of the hemostasis can lead to hemorrhage, and on the other hand to thrombosis. Intracranial neoplasms, complex surgical procedures, and head injury have a specific impact on coagulation and fibrinolysis. Moreover, the number of neurosurgical patients on medication (which interferes with platelet function and/or the coagulation systems) has increased over the past years.

METHOD

The objective of this review is to recall common hemostatic disorders in neurosurgical patients on the basis of the "new concept of hemostasis". Therefore the pertinent literature was searched to provide a structured and up to date manuscript about hemostasis in Neurosurgery.

FINDINGS

According to recent scientific publications abnormalities of the coagulation system are discussed. Pathophysiological background and the rational for specific (cost)-effective perioperative hemostatic therapy is provided.

CONCLUSIONS

Perturbations of hemostasis can be multifactorial and maybe encountered in the daily practice of neurosurgery. Early diagnosis and specific treatment is the prerequisite for successful treatment and good patients outcome.

Tonsillectomy in children

INTRODUCTION

Tonsillectomy is one of the most frequently performed surgical interventions in children. In the following, indications, preoperative evaluation, surgical techniques and postoperative complications will be discussed.

METHODS

Literature search in PubMed (National Library of Medicine) focusing on publications in German or English up to June 2008.

RESULTS

Indications are selected infectious diseases, upper airway obstruction for example due to tonsillar hypertrophy, and a suspected malignancy. Viral infections of the tonsils without upper airway obstruction are not an indication for surgery; in the case of acute bacterial tonsillitis, tonsillectomy is no longer recommended. In recurrent tonsillitis, tonsillectomy is only effective in specific and narrow indications. The indication for tonsillectomy in sleep-disordered breathing due to adenotonsillar hypertrophy has to be based on clinical assessment, medical history, and a sleep history. The most relevant risk factors are obstructive sleep apnea and coagulation disorders. A standardized history regarding hemostasis and bleeding is mandatory, and is superior to routine coagulation tests. Postoperative bleeding is still the most relevant complication of tonsillectomy and is always an emergency situation.

CONCLUSION

Tonsillectomy is one of the most frequently performed interventions in children but should be considered with care, as life-threatening complications can occur.

[Tonsillectomy in children: preoperative evaluation of risk factors]

Tonsillectomy is one of the most frequently performed surgical procedures in children and is associated with a relatively high risk of postoperative complications. The question often arises whether paediatric obstructive sleep apnoea should be diagnosed with preoperative sleep testing and whether preoperative coagulation tests should be performed in every child undergoing tonsillectomy. In order to answer these questions, the relevant German and English literature was analysed. Adenotonsillectomy in childhood usually resolves the underlying sleep-related breathing disorder. Nevertheless, especially in children with clinical risk factors such as severe sleep apnoea, obesity or craniofacial malformation, respiratory complications should be expected in the postoperative phase. Routine sleep tests prior to tonsillectomy are neither necessary nor practical for preoperative evaluation. Inherited coagulation disorders have only a limited effect on the occurrence of postoperative bleeding and the predictive value of routine coagulation tests is limited. As long as a thorough clinical history is negative, routine coagulation tests are not helpful or necessary prior to tonsillectomy in children.

[Preoperative evaluation of the bleeding history. Recommendations of the working group on perioperative coagulation of the Austrian Society for Anaesthesia, Resuscitation and Intensive Care]

Unexpected bleeding in the perioperative period is largely caused by impaired inherited or drug-induced primary haemostasis. Standard tests for plasma coagulation are predominantly employed to gauge the risk of bleeding. In accordance with several reports the subcommittee for perioperative coagulation (AGPG) of the Austrian Society of Anaesthesia, Resuscitation and Intensive Care (OGARI) recommends the use of a standardised questionnaire to detect an increased risk of bleeding. Accordingly, healthy patients of the American Society of Anesthesiologists (ASA) grades I and II without any suspicion of impaired haemostasis who are scheduled for procedures without expected transfusion requirements, need no standard tests for coagulation. In all other patients (including patients taking medication affecting coagulation, or patients who are unable to provide adequate information) platelet count, platelet function, aPTT, PT, and fibrinogen levels should be assessed.

Diagnostic approach to inherited bleeding disorders

The appropriate development of hemostasis encompasses a delicate equilibrium between anti- and prothrombotic forces developing during three distinct phases (primary hemostasis, coagulation and fibrinolysis) that are closely linked to each other and precisely regulated to close vessel wounds, promote vascular healing and maintain vessel patency. Imbalance in each of these systems produces either hemorrhagic or thrombotic disorders. Inherited bleeding disorders, caused by quantitative or qualitative alterations of either platelets or plasma proteins involved in blood coagulation and fibrinolysis, may lead to serious and lifelong bleeding conditions, the severity of which is inversely associated with the degree of the underlying defect. Rapid and reliable identification of these pathologies is worthy of focus to allow the adoption of appropriate substitutive or supportive antihemorrhagic therapies. Evaluation of the hemorrhage-prone patient requires careful recording of the medical history, attention to pertinent physical findings and the discretionary use of laboratory resources. Owing to the low diagnostic efficiency of clinical history and examination, an appropriate and reliable laboratory approach, encompassing first- and second-line testing, is essential to screen, diagnose and monitor patients with bleeding diatheses. As both the analytical sensitivity and responsiveness of traditional coagulation assays to different abnormalities differ widely, each laboratory should establish individual guidelines based on field experience and on reagent and instrument characteristics. Emerging evidence indicates that the implementation of global coagulation tests, such as the thrombin generation assay and clot waveform analysis, would provide additional information for clinical decision-making for patients with inherited bleeding disorders.