Hereditary haemorrhagic telangiectasia

Oral manifestations and dental considerations of patients with hereditary hemorrhagic telangiectasia: a scoping review

OBJECTIVE

We examined the range, nature, and extent of research conducted regarding the oral and dental implications of hereditary hemorrhagic telangiectasia (HHT) to identify gaps in the research and knowledge of the field.

STUDY DESIGN

We performed a scoping review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews and 2017 Guidance for the Conduct of Joanna Briggs Institute Scoping Reviews. We searched the MEDLINE and Web of Science databases for all full-text articles published in English from December 1946 to October 2022.

RESULTS

We identified 103 articles describing oral and dental considerations of patients with HHT, primarily case reports. Most reported oral telangiectasias of the tongue, lips, and palate. Many reported management of bleeding and the use or recommendation of prophylactic antibiotics before dental procedures.

CONCLUSIONS

Oral telangiectasias are commonly found in patients with hereditary hemorrhagic telangiectasia, and dental professionals may be the first to diagnose it in their patients. Early detection and diagnosis are important to prevent potentially fatal outcomes, and prophylactic antibiotics before procedures may be warranted.

The Potential Role of MiRs-139-5p and -454-3p in Endoglin-Knockdown-Induced Angiogenic Dysfunction in HUVECs

Hereditary hemorrhagic telangiectasia (HHT) is a rare genetic disease characterized by aberrant angiogenesis and vascular malformations. Mutations in the transforming growth factor beta co-receptor, endoglin (ENG), account for approximately half of known HHT cases and cause abnormal angiogenic activity in endothelial cells (ECs). To date, how ENG deficiency contributes to EC dysfunction remains to be fully understood. MicroRNAs (miRNAs) regulate virtually every cellular process. We hypothesized that ENG depletion results in miRNA dysregulation that plays an important role in mediating EC dysfunction. Our goal was to test the hypothesis by identifying dysregulated miRNAs in ENG-knockdown human umbilical vein endothelial cells (HUVECs) and characterizing their potential role in EC function. We identified 32 potentially downregulated miRNAs in ENG-knockdown HUVECs with a TaqMan miRNA microarray. MiRs-139-5p and -454-3p were found to be significantly downregulated after RT-qPCR validation. While the inhibition of miR-139-5p or miR-454-3p had no effect on HUVEC viability, proliferation or apoptosis, angiogenic capacity was significantly compromised as determined by a tube formation assay. Most notably, the overexpression of miRs-139-5p and -454-3p rescued impaired tube formation in HUVECs with ENG knockdown. To our knowledge, we are the first to demonstrate miRNA alterations after the knockdown of ENG in HUVECs. Our results indicate a potential role of miRs-139-5p and -454-3p in ENG-deficiency-induced angiogenic dysfunction in ECs. Further study to examine the involvement of miRs-139-5p and -454-3p in HHT pathogenesis is warranted.

Pathological Background and Clinical Procedures in Oral Surgery Haemostasis Disorders: A Narrative Review

Haemostasis disorders are serious pathologies that could put dental and surgical procedures at risk as they are associated with postoperative bleeding, which in some circumstances could be prolonged and dangerous for the patient. In-depth knowledge of the problems associated with coagulation pathologies and the suitable specific procedures should be implemented in dental practice. A good awareness of the clinical protocols to be used in these circumstances may help reduce operator stress and increase patient compliance. Collaboration with the haematologist is always recommended to establish an adequate treatment plan, both regarding the administration of therapies that promote haemostasis and for assessing the operative risk. Hereby, we summarize the congenital and hereditary pathologies that lead to haemostasis disorders, which can be found in patients undergoing dental procedures. The purpose of this narrative review is to frame the diseases from a clinical, anamnestic, and etiopathological standpoint, as well as to evaluate an operative approach to the pathology under consideration, with particular attention to anaesthesia manoeuvres and post-surgical haemostasis, to avoid hematoma formation and uncontrolled bleeding which can lead procedure failure up and even death. Of note, it is likewise important to educate the patient about prevention, to keep the oral cavity healthy and avoid invasive procedures, limiting the number of operative sessions.

Hereditary Hemorrhagic Telangiectasia Associating Neuropsychiatric Manifestations with a Significant Impact on Disease Management-Case Report and Literature Review

(1) Background: Genetic hereditary hemorrhagic telangiectasia (HHT) is clinically diagnosed. The clinical manifestations and lack of curative therapeutic interventions may lead to mental illnesses, mainly from the depression–anxiety spectrum. (2) Methods: We report the case of a 69-year-old patient diagnosed with HHT and associated psychiatric disorders; a comprehensive literature review was performed based on relevant keywords. (3) Results: Curaçao diagnostic criteria based the HHT diagnosis in our patient case at 63 years old around the surgical interventions for a basal cell carcinoma, after multiple episodes of epistaxis beginning in childhood, but with a long symptom-free period between 20 and 45 years of age. The anxiety–depressive disorder associated with nosocomephobia resulted in a delayed diagnosis and low adherence to medical monitoring. A comprehensive literature review revealed the scarcity of publications analyzing the impact of psychiatric disorders linked to this rare condition, frequently associating behavioral disengagement as a coping strategy, psychological distress, anxiety, depression, and hopelessness. (4) Conclusions: As patients with HHT face traumatic experiences from disease-related causes as well as recurring emergency hospital visits, active monitoring for mental illnesses and psychological support should be considered as part of the initial medical approach and throughout the continuum of care.

Hereditary haemorrhagic telangiectasia: A case report

Background

Hereditary haemorrhagic telangiectasia is an autosomal dominant genetic disorder characterized by abnormalities in blood vessel formation. The clinical manifestations of patients affected with hereditary haemorrhagic telangiectasia include mucocutaneous telangiectasias and visceral arteriovenous malformations.

Case Summary

We report the case of a 30-year-old female diagnosed with hereditary haemorrhagic telangiectasia presenting with the classic triad of recurrent epistaxis, mucocutaneous telangiectasias and family history of hereditary haemorrhagic telangiectasia with activin receptor-like kinase 1 mutation. Upon skin examination, she was noted to have telangiectasias under left naris, inner lower lip and surface of the tongue, and a vascular malformation on the right forearm.

Conclusion

Although the skin involvement and epistaxis may be mild symptoms and signs of hereditary haemorrhagic telangiectasia, timely recognition of these can ensure vigilant monitoring of potential severe complications from cerebral and pulmonary visceral arteriovenous malformations.

Pulmonary arterial hypertension in a patient with hereditary hemorrhagic telangiectasia and family gene analysis: A case report. World J Clin Cases 2021;9:3079-3089. [PMID: 33969094 PMCID: PMC8080754 DOI: 10.12998/wjcc.v9.i13.3079]

BACKGROUND

Hereditary hemorrhagic telangiectasia (HHT) is a rare autosomal dominant genetic disease. Very few patients suffering from HHT present with associated pulmonary arterial hypertension (PAH), which may result in a poor prognosis. Here, we report a case of HHT with PAH. The patient’s clinical manifestations and treatment as well as genetic analysis of family members are reviewed, in order to raise awareness of this multimorbidity.

CASE SUMMARY

A 45-year-old Chinese woman was admitted to the hospital to address a complaint of intermittent shortness of breath, which had lasted over the past 2 years. She also had a 30-year history of recurrent epistaxis and 5-year history of anemia. She reported that the shortness of breath had aggravated gradually over the 2 years. Physical examination discovered anemia and detected gallop rhythm in the precordium. Chest computerized tomography and cardiac ultrasound demonstrated PAH and hepatic arteriovenous malformation. The formal clinical diagnosis was HHT combined with PAH. The patient was treated with ambrisentan and her condition improved for a time. She died half a year after the diagnosis. Genetic testing revealed the patient and some family members to carry an activin A receptor-like type 1 mutation (c. 1232G>A, p. Arg411Gln); the family was thus identified as an HHT family.

CONCLUSION

We report a novel gene mutation (c. 1232G>A, p. Arg411Gln) in a Chinese HHT patient with PAH.

Founder Effects in Hereditary Hemorrhagic Telangiectasia

A founder effect can result from the establishment of a new population by individuals from a larger population or bottleneck events. Certain alleles may be found at much higher frequencies because of genetic drift immediately after the founder event. We provide a systematic literature review of the sporadically reported founder effects in hereditary hemorrhagic telangiectasia (HHT). All publications from the ACVRL1, ENG and SMAD4 Mutation Databases and publications searched for terms “hereditary hemorrhagic telangiectasia” and “founder” in PubMed and Scopus, respectively, were extracted. Following duplicate removal, 141 publications were searched for the terms “founder” and “founding” and the etymon “ancest”. Finally, 67 publications between 1992 and 2020 were reviewed. Founder effects were graded upon shared area of ancestry/residence, shared core haplotypes, genealogy and prevalence. Twenty-six ACVRL1 and 12 ENG variants with a potential founder effect were identified. The bigger the cluster of families with a founder mutation, the more remarkable is its influence to the populational ACVRL1/ENG ratio, affecting HHT phenotype. Being aware of founder effects might simplify the diagnosis of HHT by establishing local genetic algorithms. Families sharing a common core haplotype might serve as a basis to study potential second-hits in the etiology of HHT.

Arteriovenous Malformations in the Setting of Osler-Weber-Rendu: What the Radiologist Needs to Know

Osler-Weber-Rendu, also known as Hereditary Hemorrhagic Telangiectasia, is an autosomal dominant disease with phenotypic manifestations that include pulmonary, cerebrospinal, hepatic, and other visceral arteriovenous malformations (AVMs). Pulmonary AVMs can result in hypoxemia, hemoptysis, or stroke due to paradoxical embolism. The mainstay of treatment is transcatheter embolization. Central nervous system and abdominal visceral AVMs contribute to morbidity of the disease. Radiologists should be familiar with the imaging manifestations and treatment algorithm of AVMs in Osler-Weber-Rendu to effectively guide patient care.

Antithrombotic Therapy in Hereditary Hemorrhagic Telangiectasia: Real-World Data from the Gemelli Hospital HHT Registry

Although Hereditary Hemorrhagic Telangiectasia (HHT) is characterized by an overwhelming bleeding propensity, patients with this disease may also present medical conditions that require antithrombotic therapy (AT). However, precise information on indications, dosage, duration, effectiveness, and safety of AT in HHT patients is lacking. We performed a retrospective analysis of the HHT Registry of our University Hospital and found 26 patients who received AT for a total of 30 courses (19 courses of anticoagulant therapy and 11 courses of antiplatelet therapy). Indications to treatments included: atrial fibrillation, venous thrombosis and pulmonary embolism, heart valve replacement, retinal artery occlusion, secondary prevention after either stroke or myocardial infarction, and thromboprophylaxis for surgery. The total time of exposure to antiplatelet therapy was 385 months and to anticoagulant therapy 169 months. AT was generally well tolerated, with no fatal bleedings and no significant changes in hemoglobin levels. However, we found three major bleedings, with an incidence rate of 6.5 per 100 patients per year. When only patients treated with anticoagulants were considered, the incidence rate of major bleedings increased to 21.6 per 100 patients per year. Our study indicates that major bleeding may occur in HHT patients receiving AT, with a substantially increased rate in those treated with anticoagulants. Further studies are needed to fully estimate the tolerability of antithrombotic drugs in HHT.

Hereditary hemorrhagic telangiectasia: how to efficiently detect hepatic abnormalities using ultrasonography

INTRODUCTION

Hereditary hemorrhagic telangiectasia (HHT) is a multiorgan genetic angiodysplastic affection characterized by visceral vascular malformations. It affects mainly the brains, lungs, gastrointestinal tract, and nasal mucosa. Unlike those organs, hepatic involvement, although very frequently occurring, is insufficiently recognized, mainly because of the complex vascular structure of this organ. Thus, treating HHT patients requires a solid understanding of these hepatic anomalies. It is especially important for any general clinicians to be able to recognize clinical findings in HHT, which leads to a high suspicion of HHT and have an index of suspicion for liver abnormalities of HHT. For this purpose, keen awareness of clinical as well as hepatic sonographic (US) findings is paramount.

AIM

The aim of this review is to summarize previously reported findings on the hepatic US through a thorough analysis of related articles, and to (a) determine the role of US in the diagnosis of hepatic involvement in HHT patients and (b) propose the most simple and easy way to detect HHT-related abnormalities during routine US examinations.

CONCLUSION

Hepatic US serves to diagnose the detailed complex hepatic changes typical of HHT, and contributes to increased diagnostic confidence of hepatic changes in HHT patients, with the most simple way not to overlook HHT-related abnormalities being to find hepatic artery dilatation.

Pitfalls of delaying the diagnosis of hereditary haemorrhagic telangiectasia

Hereditary haemorrhagic telangiectasia (HHT; Osler–Weber–Rendu disease) is an autosomal dominant vascular disease characterized by nosebleeds, mucocutaneous telangiectases, visceral arteriovenous malformations (AVM) and a first-degree relative with HHT. Diagnosis is definite if three or four criteria are present. This case report describes a 19-year-old male with incidentally detected polycythaemia and an associated soft-tissue opacity over the left lower lobe on his frontal chest radiogram. He had experienced dyspnoea on exertion since infancy and clubbing at physical examination. Polycythaemia vera, chronic obstructive pulmonary disease, sleep apnoea and cyanotic congenital heart disease were excluded. Chest computed tomography (CT) was initially refused by the patient, but 3 years later he presented with severe epistaxis. Considering the unvarying soft tissue mass and erythrocytosis, an HHT-associated pulmonary AVM (PAVM) was eventually confirmed by chest CT. A pathogenic family-specific ENG c.817-2 A>C mutation was detected in the patient. The large PAVM was successfully treated using AMPLATZER™ vascular plug embolization. A combination of the multisystemic nature of his symptoms, the age-related penetrance of HHT symptoms and insufficient patient compliance delayed the diagnosis of HHT in this current case.

Case Report: Hepatopulmonary syndrome as the first clinical manifestation of cirrhosis in a patient with underlying chronic lung disease

An 86 year old woman with multiple chronic lung diseases (including chronic obstructive pulmonary disease, bronchiectasis, and untreated mycobacterium avium-intracellulare) presented with two weeks of increased shortness of breath, notably worse when seated as compared to when lying down. After treatments focused on her known conditions did not resolve her dyspnea, the differential diagnosis was broadened and she was found to have evidence of cirrhosis on imaging. As a result of this new diagnosis, transthoracic echocardiography and arterial blood gas analysis were performed and together yielded the diagnosis of hepatopulmonary syndrome. We describe a rare presentation of hepatopulmonary syndrome manifesting as a patient’s first clinical evidence of suspected cirrhosis, a diagnosis made difficult by this patient’s numerous other lung diseases which muddied the picture.

Osler-Weber-Rendu Syndrome in Relation to Dermatology

Osler-Weber-Rendu syndrome, also known as hereditary hemorrhagic telangiectasia, is a rare autosomal dominant disorder with an estimated worldwide prevalence of 1 case per 10,000 population. Its clinical manifestations are the result of arteriovenous malformations characterized by telangiectases that can affect the skin, mucous membranes, and solid organs and cause life-threatening conditions, such as liver disease, systemic emboli, and heart failure. Timely diagnosis is thus essential in order to prevent disease-related complications and offer genetic counseling to families. We review the clinical features of Osler-Weber-Rendu syndrome with a focus on mucocutaneous manifestations and their treatment.

Living with Hereditary Haemorrhagic Telangiectasia: stigma, coping with unpredictable symptoms, and self-advocacy

Objective: Hereditary Haemorrhagic Telangiectasia (HHT) is a genetic condition causing frequent nose bleeds, skin lesions (telangiectasia) and arteriovenous malformations. Approximately, 50% of people experience life-threatening HHT symptoms including haemorrhages in the brain, lungs and liver. This study aimed to gain a qualitative understanding of the psychosocial impact of HHT over time. Design: Using a phenomenological framework, a rigorous narrative analysis was performed on 20 semi-structured interviews with individuals with HHT aged 20s-60s. Main outcome measures: Qualitative themes explaining life experiences prior to and following a clinical diagnosis of HHT. Results: Narratives highlighted four psychosocial themes: (i) the psychological impact of visible symptoms was significant and related to experiences of social stigma, (ii) individuals struggled to identify triggers of symptoms in order to reduce unpredictability, (iii) an illness identity was rejected by minimising HHT when talking about the present self, and by positive reframing as 'lucky' and (iv) self-advocacy was necessitated due to lack of expert coordinated care. Conclusion: HHT has a demanding impact on social, physical and psychological well-being. These findings have significant implications for health care, as narratives about interactions with health professionals often used the terms 'frustrating' and 'not being heard'.

Severe Recurrent Epistaxis - The Main Symptom of Hereditary Haemorrhagic Teleangiectasia

Hereditary haemorrhagic telangiectasia (HHT), also known as Rendu-Osler-Weber syndrome, is of dominant autosomal inheritance. Pathologic changes of vascular walls cause recurrent episodes of bleeding from many organ systems. Recurrent epistaxis is the first and the most frequent symptom of HHT. The causal therapy is not known but there are many therapeutic procedures improving the overall condition.

We present a case of a 76-year-old man suffering from HHT, frequently hospitalized and treated for massive nose bleeding. In past a selective arterial embolization was performed thrice; nonetheless, the intensity and frequency of epistaxis remained unchanged. Anterior nasal package and electrocoagulation were performed repeatedly as the “first aid” treatment. In the article we also mention other therapeutic modalities for this diagnosis; unfortunately, their efficacy remains inadequate.

The Stratified Population Screening of Hereditary Hemorrhagic Telangiectasia

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant multisystemic vascular disease with a wordwide prevalence of 1:5000-1:10000. We introduce our algorithm for the stratified population screening of HHT. Probands are selected from the consecutive hospital database review for HHT (I7800) and recurrent epistaxis (R0400) and the review of patient records referred by family practicioners. A proportion of probands might be de novo diagnosed with HHT in the 10-year study period. The checkup of probands consists of physical examination, arteriovenous malformation exploration and and genetic testing (ACVRL1 and ENG sequence analysis). The family screening of HHT consists of physical examination and screening for the family-specific mutation of each at-risk individual, and furthermore, arteriovenous malformation exploration in individuals with suspected/definite HHT and/or carrying the mutation. Twenty-five definite HHT patients were explored: 7 of them by the I7800 review, 1 by the R0400 review, 3 were de novo diagnosed, and the remaining 14 were explored by the systematic family screening. Considering the 20 patients alive at the end of the study period and the unavailable 5 potential HHT patients and 12 at-risk family members, the HHT prevalence is estimated to be 1:6090-1:11267 in our study area, implying our algorithm's effectivity in the stratified population screening of HHT.

Differential diagnosis of hepatopulmonary syndrome (HPS): Portopulmonary hypertension (PPH) and hereditary hemorrhagic telangiectasia (HHT)

Hepatopulmonary syndrome (HPS) is a severe complication of advanced liver disease associated with an extremely poor prognosis. HPS is diagnosed in 4-47% of patients with cirrhosis and in 15-20% of candidates for liver transplantation. In addition, severe hypoxia is associated with a high risk of complications of liver transplantation (a 30% chance during the first 90 days) and increases the gap between transplantation and improving arterial oxygenation. The pathogenesis of HPS is not fully understood, and no effective pharmacological treatment has been developed yet. Currently, the treatment of choice for HPS is orthotopic liver transplantation. Non-specific clinical criteria and the lack of standardized diagnostic criteria for determining HPS can lead to diagnostic errors. Portopulmonary hypertension and hereditary hemorrhagic telangiectasia, also known as Osler-Weber-Rendu syndrome, are pulmonary complications of liver disease which should be differentially diagnosed from HPS.

Megakaryocytic Smad4 Regulates Platelet Function through Syk and ROCK2 Expression

Smad4, a key transcription factor in the transforming growth factor-β signaling pathway, is involved in a variety of cell physiologic and pathologic processes. Here, we characterized megakaryocyte/platelet-specific Smad4 deficiency in mice to elucidate its effect on platelet function. We found that megakaryocyte/platelet-specific loss of Smad4 caused mild thrombocytopenia and significantly extended first occlusion time and tail bleeding time in mice. Smad4-deficient platelets showed reduced agonist-induced platelet aggregation. Further studies showed that a severe defect was seen in integrin α_IIbβ₃-mediated bidirectional (inside-out and outside-in) signaling in Smad4-deficient platelets, as evidenced by reduced fibrinogen binding and α-granule secretion, suppressed platelet spreading and clot retraction. Microarray analysis showed that the expression levels of multiple genes were altered in Smad4-deficient platelets. Among these genes, spleen tyrosine kinase (Syk) and Rho-associated coiled-coil containing protein kinase 2 (ROCK2) were downregulated several times as confirmed by quantitative reverse-transcription polymerase chain reaction and immunoblotting. Further research showed that Smad4 directly regulates ROCK2 transcription but indirectly regulates Syk. Megakaryocyte/platelet-specific Smad4 deficiency caused decreased expression levels of Syk and ROCK2 in platelets. These results suggest potential links among Smad4 deficiency, attenuated Syk, and ROCK2 expression and defective platelet activation.

Intravenous Bevacizumab Therapy in a Patient with Hereditary Hemorrhagic Telangiectasia, ENG E137K, Alcoholic Cirrhosis, and Portal Hypertension

Intravenous bevacizumab decreased mucosal bleeding in some patients with hereditary hemorrhagic telangiectasia (HHT). We treated a 47-year-old male who had HHT, severe epistaxis, and gastrointestinal bleeding, alcoholic cirrhosis, and portal hypertension with intravenous bevacizumab 2.5 mg/kg every 2 weeks. We tabulated these measures weekly during weeks 1–33 (no bevacizumab); 34–57 (bevacizumab); and 58–97 (no bevacizumab): hemoglobin (Hb) levels; platelet counts; units of transfused packed erythrocytes (PRBC units); and quantities of iron infused as iron dextran to support erythropoiesis. We performed univariate and multivariable analyses. We sequenced his ENG and ACVRL1 genes. Epistaxis and melena decreased markedly during bevacizumab treatment. He reported no adverse effects due to bevacizumab. Mean weekly Hb levels were significantly higher and mean weekly PRBC units and quantities of intravenous iron were significantly lower during bevacizumab treatment. We performed a multiple regression on weekly Hb levels using these independent variables: bevacizumab treatment (dichotomous); weekly platelet counts; weekly PRBC units; and weekly quantities of intravenous iron. There was 1 positive association: (bevacizumab treatment; p = 0.0046) and 1 negative association (PRBC units; p = 0.0004). This patient had the novel ENG mutation E137K (exon 4; c.409G→A). Intravenous bevacizumab treatment 2.5 mg/kg every 2 weeks for 24 weeks was well-tolerated by a patient with HHT due to ENG E137K and was associated with higher weekly Hb levels and fewer weekly PRBC units.

Von Willebrand factor and angiogenesis: basic and applied issues

The recent discovery that von Willebrand factor (VWF) regulates blood vessel formation has opened a novel perspective on the function of this complex protein. VWF was discovered as a key component of hemostasis, capturing platelets at sites of endothelial damage and synthesized in megakaryocytes and endothelial cells (EC). In recent years, novel functions and binding partners have been identified for VWF. The finding that loss of VWF in EC results in enhanced, possibly dysfunctional, angiogenesis is consistent with the clinical observations that in some patients with von Willebrand disease (VWD), vascular malformations can cause severe gastrointestinal (GI) bleeding. In vitro and in vivo studies indicate that VWF can regulate angiogenesis through multiple pathways, both intracellular and extracellular, although their relative importance is still unclear. Investigation of these pathways has been greatly facilitated by the ability to isolate EC from progenitors circulating in the peripheral blood of normal controls and patients with VWD. In the next few years, these will yield further evidence on the molecular pathways controlled by VWF and shed light on this novel and fascinating area of vascular biology. In this article, we will review the evidence supporting a role for VWF in blood vessel formation, the link between VWF dysfunction and vascular malformations causing GI bleeding and how they may be causally related. Finally, we will discuss how these findings point to novel therapeutic approaches to bleeding refractory to VWF replacement therapy in VWD.

Technique modifications for septodermoplasty: an illustrative case

Background

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant disease that results in telangiectasia of the sinonasal tract, gastro-intestinal tract as well as possible arteriovenous malformations of the lung, liver and brain. One of the most common disease manifestations of HHT is epistaxis. Severe recurrent epistaxis necessitating iron therapy and blood transfusion is often managed with septodermoplasty. Its initial description was as an open surgical technique requiring nasal packing.

Case presentation

We describe a modified approach to septodermoplasty done completely endoscopically and without nasal packing for a patient with severe epistaxis due to HHT.

Conclusion

The described technique modifications for the presented case allowed for same day discharge following surgery, complete take of the skin graft and resultant epistaxis control that ended thepatient's transfusion dependency. The merits of these modifications should be further evaluated in a clinical trial.

Bleeding and clotting in hereditary hemorrhagic telangiectasia

Hereditary hemorrhagic telangiectasia (HHT) is a relatively common inherited vascular disorder that was first described in 1864, and is notable for epistaxis, telangiectasia, and arterial venous malformations. While genetic tests are available, the diagnosis remains clinical, and is based on the Curacao criteria. Patients with HHT are at increased risk for both bleeding and clotting events. Because of these competing complications, hematologists are often faced with difficult clinical decisions. While the majority of management decisions revolve around bleeding complications, it is not infrequent for these patients to require anticoagulation for thrombosis. Any anticoagulation recommendations must take into account the bleeding risks associated with HHT. Recent reviews have found that HHT patients can be safely anticoagulated, with the most frequent complication being worsened epistaxis. Large clinical trials have shown that factor IIa and Xa inhibitors have less intracranial bleeding than warfarin, and basic coagulation research has provided a possible mechanism. This article describes the anticoagulation dilemma posed when a 62-year-old female patient with a history of bleeding events associated with HHT was diagnosed with a pulmonary embolism. The subsequent discussion focuses on the approach to anticoagulation in the HHT patient, and addresses the role of the new oral anticoagulants.

Rendu-Osler-Weber Syndrome: A Case Report

Hereditary hemorrhagic telangectasia (HHT) or Rendu-Osler-Weber syndrome, is a rare genetic disorder with autosomal dominance and variable penetrance. The typical findings of the disease are telangiectasias in skin and mucous membranes, and arteriovenous malformations presenting in the organs like lung, intestine, brain and liver. It is characterized by the classic triad of recurrent epistaxis, mucocutaneous telangiectasias and visceral hemorrhages, with familial occurrence. This article describes a case of HHT of an adult patient, associated with multiple angiodysplasic injuries in the nasal mucosa, upper gastrointestinal tract, lungs and who presents continuous blood loss, resulting iron deficiency anemia. Based on clinical and diagnostic findings, we diagnosed this case as HHT, which has rarely been reported in our literature.

Coincidence of Glanzmann's thrombasthenia with hereditary haemorrhagic telengiectasia in a man with gastrointestinal bleeding

Here we report a case of a 57-year-old man referred to our hospital with weakness, lethargy, melena, and rectorrhalgia. His physical examination and past medical history showed gingival bleeding, several episodes of epistaxis and post-surgery bleeding. Primary laboratory evaluation revealed only anaemia. Gastrointestinal findings including upper endoscopy and colonoscopy documented normal status, but balloon endoscopy illustrated telengiectasia-like lesions in the mid-jejunum. The case was suspected to be haemophilia due to the past medical history, although complete haemostatic evaluation demonstrated Glanzmann's thrombasthenia. The diagnosis of co-occurrence of hereditary haemorrhagic telengiectasia and Glanzmann's thrombasthenia was confirmed. This case revealed the coincidence of two bleeding tendencies, which, although rare, is a possible phenomenon. We recommend carrying out both primary and secondary haemostatic profiles for every patient with bleeding diathesis.

Redo cardiac surgery for active prosthetic valve endocarditis associated with hereditary hemorrhagic telangiectasia: report of a case

Hereditary hemorrhagic telangiectasia (HHT) is caused by an autosomal dominant gene and characterized by multiple arteriovenous malformations in several organs, leading to bleeding or shunting. These patients often suffer severe infections and heart failure, which should be managed in the perioperative period, when open heart surgery is indicated. We report a case of successful aortic root replacement for active prosthetic valve endocarditis and ventricular septal perforation in a patient with HHT, who had severe heart failure.

Standard anticoagulation for mesenteric vein thrombosis, revealing a 'zebra' diagnosis: hereditary haemorrhagic telangiectasia--the dripping truth!

A 60-year-old man was treated in the hospital for mesenteric vein thrombosis and discharged home on anticoagulation. On warfarin the patient started to bleed profusely from the nose and tongue. He was evaluated by ENT (ears, nose and throat); a nasal endoscopy revealed several vascular ectasias. Subsequent detailed history and general physical examination established the diagnosis of hereditary haemorrhagic telangiectasia also known as Osler-Weber-Rendu syndrome. On further evaluation, pulmonary arteriovenous malformations were diagnosed on imaging and treated by intervention radiology. In hindsight, the diagnosis could have been made in the general practitioner's office with just a routine thorough history and a physical examination at a new patient visit. We report this case to stress upon the importance of vigilant clinical, medical and family history and a thorough examination to establish an early diagnosis of this not-so-rare entity.

Hereditary hemorrhagic telangiectasia: arteriovenous malformations in children

OBJECTIVE

To evaluate the clinical features in a large cohort of pediatric patients with genetically confirmed hereditary hemorrhagic telangiectasia (HHT) and to identify possible predictors of arteriovenous malformation (AVM) onset or clinical significance.

STUDY DESIGN

Prospective cross-sectional survey of all children subjected to screening for AVMs in the multidisciplinary HHT center. All patients proved to be carriers of endoglin mutations or activin A receptor type-II-like kinase 1 mutations, defined as HHT1 and HHT2, respectively. A full clinical-radiological protocol for AVM detection was adopted, independent from presence or absence of AVM-related symptoms.

RESULTS

Forty-four children (mean age, 10.3 years; range, 1-18) were subjected to a comprehensive clinical-radiologic evaluation. This investigation disclosed cerebrovascular malformations in 7 of 44 cases, pulmonary AVMs in 20 of 44 cases, and liver AVMs in 23 of 44 cases. Large visceral AVMs were found in 12 of 44 children and were significantly more frequent in patients with HHT1. Only large AVMs were associated with symptoms and complications.

CONCLUSIONS

Children with HHT have a high prevalence of AVMs; therefore, an appropriate clinical and radiological screening protocol is advisable. Large AVMs can be associated with complications in childhood, whereas small AVMs probably have no clinical risk.

Oral vascular malformation in a patient with hereditary hemorrhagic telangiectasia: a case report

Hereditary hemorrhagic telangiectasia (HHT) is an inherited mucocutaneous disease characterized by recurrent epistaxis, lesions on skin and oral mucosa, and arteriovenous malformations of the soft tissues. This article describes the treatment of a 64-year-old woman with a bleeding nodule, which was diagnosed as an arteriovenous malformation of the gingival mucosa. She was treated using sclerotherapy. Patients with HHT can be treated in the dental office and vascular malformations of these patients can be successfully managed with sclerotherapy, which eliminates the need for invasive surgical procedures and the possibility of postsurgical complications.

Deep vein thrombosis induced by thalidomide to control epistaxis secondary to hereditary haemorrhagic telangiectasia

Thalidomide was recently reported to reduce the severity and frequency of epistaxes in patients with hereditary haemorrhagic telangiectasia (HHT). We here describe the case of a patient with HHT and severe epistaxes refractory to medical and local surgical treatments who developed an extensive deep vein thrombosis shortly after initiation of treatment with thalidomide. This is the first report of venous thromboembolic complication induced by thalidomide prescribed in this setting. Although thalidomide was recently found to provide an alternative therapeutic strategy in patients with HHT and refractory epistaxes, this agent should be used with great caution in this indication, given its thrombogenicity and difficulties to manage systemic anticoagulation in patients with HHT.

Individualized therapy of HHT driven by network analysis of metabolomic profiles

Background

Hereditary Hemorrhagic Telangiectasia (HHT) is an autosomal dominant disease with a varying range of phenotypes involving abnormal vasculature primarily manifested as arteriovenous malformations in various organs, including the nose, brain, liver, and lungs. The varied presentation and involvement of different organ systems makes the choice of potential treatment medications difficult.

Results

A patient with a mixed-clinical presentation and presumed diagnosis of HHT, severe exertional dyspnea, and diffuse pulmonary shunting at the microscopic level presented for treatment. We sought to analyze her metabolomic plasma profile to assist with pharmacologic treatment selection. Fasting serum samples from 5 individuals (4 healthy and 1 with HHT) were metabolomically profiled.

A global metabolic network reconstruction, Recon 1, was used to help guide the choice of medication via analysis of the differential metabolism between the patient and healthy controls using metabolomic data. Flux Balance Analysis highlighted changes in metabolic pathway activity, notably in nitric oxide synthase (NOS), which suggested a potential link between changes in vascular endothelial function and metabolism. This finding supported the use of an already approved medication, bevacizumab (Avastin). Following 2 months of treatment, the patient's metabolic profile shifted, becoming more similar to the control subject profiles, suggesting that the treatment was addressing at least part of the pathophysiological state.

Conclusions

In this 'individualized case study' of personalized medicine, we carry out untargeted metabolomic profiling of a patient and healthy controls. Rather than filtering the data down to a single value, these data are analyzed in the context of a network model of metabolism, in order to simulate the biochemical phenotypic differences between healthy and disease states; the results then guide the therapy. This presents one approach to achieving the goals of individualized medicine through Systems Biology and causal models analysis.

Spectral imaging reveals microvessel physiology and function from anastomoses to thromboses

Abnormal microvascular physiology and function is common in many diseases. Numerous pathologies include hypervascularity, aberrant angiogenesis, or abnormal vascular remodeling among the characteristic features of the disease, and quantitative imaging and measurement of microvessel function can be important to increase understanding of these diseases. Several optical techniques are useful for direct imaging of microvascular function. Spectral imaging is one such technique that can be used to assess microvascular oxygen transport function with high spatial and temporal resolution in microvessel networks through measurements of hemoglobin saturation. We highlight novel observation made with our intravital microscopy spectral imaging system employed with mouse dorsal skin-fold window chambers for imaging hemoglobin saturation in microvessel networks. Specifically, we image acute oxygenation fluctuations in a tumor microvessel network, the development of arteriovenous malformations in a mouse model of hereditary hemorrhagic telangiectasia, and the formation of spontaneous and induced microvascular thromboses and occlusions.

Pediatric otolaryngologic manifestations of bleeding disorders

OBJECTIVE

In 1930, considering the diseases of the blood and lymphatic glands in relation to otolaryngology, Goldsmith and McGregor stated that "... the otolaryngologist has frequently to deal with bleeding from the nose and throat ...". After approximately 8 decades, in particular preoperatively, the use of universal coagulation screening in children is still controversial. Aim of the present review was to offer a concise but complete discussion of clotting disorders with pediatric otolaryngological interest recognizing: (i) vascular disorders, (ii) platelet disorders, (iii) disorders of coagulation, and (iv) thrombosis.

METHODS

An exhaustive review of literature was performed to investigate available data and evidences regarding pediatric otolaryngologic manifestations of bleeding disorders.

RESULTS/CONCLUSIONS

Modern otolaryngologists should be familiar with common bleeding disorders since many have head and neck manifestations. This knowledge allows the choice of appropriate pre-operative screening of surgical patients. The most important component of the preoperative assessment is the bleeding history that directs further laboratory evaluation. All otolaryngologic surgical procedures in children with bleeding disorders should be carried out with the close co-operation of the Haematology Department.