Multiple intrapulmonary arteriovenous fistulas in childhood

Treatment of telomeropathies

Telomeropathies or telomere biology disorders (TBDs) are a group of rare diseases characterised by altered telomere maintenance. Most patients with TBDs show pathogenic variants of genes that encode factors involved in the prevention of telomere shortening. Particularly in adults, TBDs mostly present themselves with heterogeneous clinical features that often include bone marrow failure, hepatopathies, interstitial lung disease and other organ sites. Different degrees of severity are also observed among patients with TBDs, ranging from very severe syndromes manifesting themselves in early childhood, such as Revesz syndrome, Hoyeraal-Hreidarsson syndrome, and Coats plus disease, to dyskeratosis congenita (DKC) and adult-onset "cryptic" forms of TBD, which often affect fewer organ systems. Overall, the most relevant clinical complications of TBD are bone marrow failure, lung fibrosis, and liver cirrhosis. In this review, we summarise recent advances in the management and treatment of TBD and provide a brief overview of the various treatment approaches.

An update on the biology and management of dyskeratosis congenita and related telomere biology disorders

Introduction: Telomere biology disorders (TBDs) encompass a group of illnesses caused by germline mutations in genes regulating telomere maintenance, resulting in very short telomeres. Possible TBD manifestations range from complex multisystem disorders with onset in childhood such as dyskeratosis congenita (DC), Hoyeraal-Hreidarsson syndrome, Revesz syndrome and Coats plus to adults presenting with one or two DC-related features.Areas covered: The discovery of multiple genetic causes and inheritance patterns has led to the recognition of a spectrum of clinical features affecting multiple organ systems. Patients with DC and associated TBDs are at high risk of bone marrow failure, cancer, liver and pulmonary disease. Recently, vascular diseases, including pulmonary arteriovenous malformations and gastrointestinal telangiectasias, have been recognized as additional manifestations. Diagnostics include detection of very short leukocyte telomeres and germline genetic testing. Hematopoietic cell transplantation and lung transplantation are the only current therapeutic modalities but are complicated by numerous comorbidities. This review summarizes the pathophysiology underlying TBDs, associated clinical features, management recommendations and therapeutic options.Expert opinion: Understanding TBDs as complex, multisystem disorders with a heterogenous genetic background and diverse phenotypes, highlights the importance of clinical surveillance and the urgent need to develop new therapeutic strategies to improve health outcomes.

Successful use of calcium channel blocker for management of arterio-venous malformations following Fontan procedure

In diffuse forms of arteriovenous malformation following Fontan procedure, "classical" medical therapy, inhaled nitric oxide and sildenafil, may play a role, until re-direction of hepatic flow to pulmonary circulation cures it. However, in refractory cases, as reported in our 2-year-old patient, unusual medications such as calcium channel blockers can be tried and continued if patients respond adequately.

Hepatopulmonary syndrome is a frequent cause of dyspnea in the short telomere disorders

BACKGROUND

Telomere syndromes have their most common manifestation in idiopathic pulmonary fibrosis and emphysema. The short telomere defect in these patients may manifest systemically as bone marrow failure and liver disease. We sought to understand the causes of dyspnea in telomerase and telomere gene mutation carriers who have no parenchymal lung disease.

METHODS

Clinical and pathologic data were reviewed as part of a Johns Hopkins-based natural history study of short telomere syndromes including dyskeratosis congenita.

RESULTS

Hepatopulmonary syndrome (HPS) was diagnosed in nine of 42 cases (21%). Their age at presentation was significantly younger than that of cases initially presenting with pulmonary fibrosis and emphysema (median, 25 years vs 55 years; P < .001). Cases had evidence of intra- and extrapulmonary arteriovascular malformations that caused shunt physiology. Nodular regenerative hyperplasia was the most frequent histopathologic abnormality, and it was seen in the absence of cirrhosis. Dyspnea and portal hypertension were progressive, and the median time to death or liver transplantation was 6 years (range, 4-10 years; n = 6). In cases that underwent liver transplantation, dyspnea and hypoxia improved, but pulmonary fibrosis subsequently developed.

CONCLUSIONS

This report identifies HPS as a frequent cause of dyspnea in telomerase and telomere gene mutation carriers. While it usually precedes the development of parenchymal lung disease, HPS may also co-occur with pulmonary fibrosis and emphysema. Recognizing this genetic diagnosis is critical for management, especially in the lung and liver transplantation setting.

Fatal bilateral pneumothoraces complicating dyskeratosis congenita: a case report

INTRODUCTION

Dyskeratosis congenita is a rare genodermatosis, characterized by a triad of reticular skin pigmentation, nail dystrophy and leukoplakia of mucous membranes. It is also associated with a variety of non-cutaneous abnormalities such as bone marrow failure, malignancy and pulmonary complications. Among its wide range of clinical manifestations, fatal pneumothorax has rarely been reported.

CASE PRESENTATION

We report the case of a 31-year-old Lebanese woman with dyskeratosis congenita who succumbed to devastating bilateral pneumothoraces.

CONCLUSION

Careful surveillance of patients with dyskeratosis congenita is required as incipient respiratory failure due to pneumothorax may be successfully treated if detected at an early stage.

Prevalence of hepatopulmonary syndrome in children

OBJECTIVE

The hepatopulmonary syndrome is defined as a triad of liver disease, hypoxemia, and intrapulmonary vascular dilation. The reported prevalence of hepatopulmonary syndrome in adults with cirrhosis ranges from 4% to 29%; however, the prevalence of hepatopulmonary syndrome and its outcome in children is unknown. The objective of this study was to describe prospectively the prevalence of intrapulmonary vascular dilation and hepatopulmonary syndrome in children with liver disease.

METHODS

Pulse oximetry was undertaken in children with liver disease, and those with oxygen saturation < or = 97%, those with cirrhosis, and those with clinically severe portal hypertension from other causes underwent contrast-enhanced echocardiography for detection of intrapulmonary vascular dilations. Patients with intrapulmonary vascular dilation underwent arterial blood gas analysis and technetium-99m-labeled macroaggregated albumin scan.

RESULTS

Oxygen saturation was measured in 301 children and was < or = 97% in 8. These 8 and an additional 18 patients with cirrhosis or portal hypertension underwent contrast-enhanced echocardiography. Seven (27%) patients had intrapulmonary vascular dilation detected by contrast-enhanced echocardiography; 2 of these patients had abnormal arterial blood gas analysis and thus met diagnostic criteria for hepatopulmonary syndrome (representing 8% of patients with cirrhosis or severe portal hypertension). Both patients with hepatopulmonary syndrome had abnormal pulse oximetry. Technetium-99m-labeled macroaggregated albumin scans for 6 patients showed a median 6.5% (range: 4%-12%) tracer uptake outside the lungs.

CONCLUSIONS

Hepatopulmonary syndrome occurs in an important minority of children with cirrhosis or severe portal hypertension. Additional studies should be undertaken to determine the importance of intrapulmonary vascular dilation without hepatopulmonary syndrome and the impact of hepatopulmonary syndrome on the outcomes of affected children.

Diffuse Pulmonary Arteriovenous Malformations in a Teenager with Corrected Total Anomalous Pulmonary Venous Drainage

This case report describes a 13-year-old boy with diffuse microvascular pulmonary arteriovenous malformations, in whom total anomalous pulmonary venous drainage had been corrected surgically in the newborn period. Contrast transesophageal echocardiography, cardiac catheterization and a lung perfusion scan suggested, and lung biopsy confirmed the diagnosis in our patient. Treatment with nifedipin was commenced.

CONCLUSION

This case illustrates the diagnostic difficulties with this rare malformation.

Small pulmonary arteriovenous fistulae revealed by scintigraphy during selective injection of 99Tc(m)-macroaggregated albumin

We report a case of small pulmonary arteriovenous fistulae precisely diagnosed by a combination of selective pulmonary arteriography and scintigraphy during (99)Tc(m)-macroaggregated albumin injection via the peripheral pulmonary artery.

Double trouble: prolapsing epiglottis and unexpected dual pathology in an infant

A 3-week-old full-term female neonate was admitted with a 4-day history of episodic stridor, desaturations and difficult feeding. Initial assessment using fluoroscopy suggested distal tracheomalacia. Inhalational induction for examination under anaesthesia of the upper airway at 4 weeks of age caused almost complete airway obstruction due to severe anterior, or epiglottic, laryngomalacia. This airway obstruction was unresponsive to continuous positive airway pressure, the use of an oropharyngeal airway and hand ventilation and required urgent tracheal intubation using suxamethonium. Epiglottopexy, a relatively unknown procedure, was performed uneventfully 2 days later, with complete relief of the respiratory compromise. However, the infant remained desaturated postoperatively. A ventilation perfusion scan subsequently revealed multiple pulmonary arteriovenous malformations, unsuitable for embolization and requiring nocturnal home oxygen therapy. Review at 3 months of age found a thriving infant with no airway obstruction and good epiglottic positioning on examination under anaesthesia. Although the patient's oxygen requirements had diminished, the long-term outcome remains uncertain.

Differential diagnosis between patent foramen ovale and pulmonary arteriovenous fistula in two patients with previous cryptogenic stroke caused by presumed paradoxical embolism

Development of improved devices for interventional closure of atrial septal defect and patent foramen ovale increased the number of adult patients who are being referred for transcatheter closure. We report two cases that were scheduled for patent foramen ovale closure because of a right-to-left atrial shunt detected at contrast transesophageal echocardiography in another institution and that were found to have pulmonary arteriovenous fistulas. Embolization of pulmonary arteriovenous fistulas was carried out successfully by transcatheter technique.