Stroke and Respiratory Failure: Mind the Shunt!

When stroke patients present with respiratory failure, the first thought that clinicians have is that it is probably related to aspiration pneumonia. However, other causes should be considered, such as intracardiac or intrapulmonary shunts, that could present with paradoxical embolism. Paradoxical embolism is a rare entity defined by the occurrence of a venous thrombotic event associated with a systemic arterial embolism. Frequently, paradoxical embolism presents with platypnoea-orthodeoxia syndrome. Platypnoea-orthodeoxia syndrome is uncommon and is characterized by dyspnoea and hypoxaemia induced by orthostatic position, where symptoms and oxygenation are relieved by recumbency. The authors report a case of a patient who presented with an ischaemic stroke and progression to platypnoea-orthodeoxia syndrome with documentation of simultaneous pulmonary embolism and pulmonary arteriovenous malformations.

Ischemic Stroke and Pulmonary Arteriovenous Malformations: A Review

The potential of covert pulmonary arteriovenous malformations (PAVMs) to cause early onset, preventable ischemic strokes is not well known to neurologists. This is evident by their lack of mention in serial American Heart Association/ American Stroke Association (AHA/ASA) Guidelines, and the single case-report biased literature of recent years. To inform, we performed PubMed and Cochrane database searches for major studies on ischemic stroke and PAVMs published from January 1, 1974 through April 3, 2021. This identified twenty-four major observational studies, three societal guidelines, one nationwide analysis, three systematic reviews, twenty-one other review/opinion articles, and eighteen recent (2017-2021) case-reports/series that were synthesized. Key points are that patients with PAVMs suffer ischemic stroke a decade earlier than routine stroke, losing nine extra healthy-life-years per patient in the recent US nationwide analysis (2005-2014). Large-scale thoracic CT screens of the general population in Japan estimate PAVM prevalence to be 38/100,000 (95% confidence interval 18-76), with ischemic stroke rates exceeding 10% across PAVM series dating back to the 1950s, with most PAVMs remaining undiagnosed until the time of clinical stroke. Notably, the rate of PAVM diagnoses doubled in US ischemic stroke hospitalizations between 2005-2014. The burden of silent cerebral infarction approximates to twice that of clinical stroke. Over 80% patients have underlying hereditary hemorrhagic telangiectasia (HHT). The predominant stroke mechanism is paradoxical embolization of platelet-rich emboli, with iron-deficiency emerging as a modifiable risk-factor. PAVM related ischemic strokes may be cortical or subcortical, but very rarely cause proximal large vessel occlusions. Single antiplatelet therapy maybe effective for secondary stroke prophylaxis, with dual antiplatelet or anticoagulation therapy requiring nuanced risk-benefit analysis given their risk of aggravating iron deficiency. In conclusion, this review summarizes the current ischemic stroke burden from PAVMs, the implicative pathophysiology, and relevant diagnostic and treatment overviews to facilitate future incorporation into AHA/ASA guidelines.

Complex, Isolated Pulmonary Arteriovenous Malformation in Two Children With Severe Cyanosis.

We present two cases of Isolated complex pulmonary arteriovenous malformations in two children presenting with cyanosis and exercise intolerance. We present the anatomical features and the management of each case. One patient was treated with surgical ligation of the draining vein, and one patient was treated percutaneously by closure of the feeding segmental artery.

Hypoxemia indicative of Rendu Osler disease during SARS Cov-2 pandemic

Rendu Osler’s disease is a genetic disease characterized by mucocutaneous and visceral telangiectasias. Rendu Osler’s disease was discovered during hypoxemia during an outbreak of SARS-Cov2.This was a 36-year-old woman with exertional dyspnea and severe hypoxemia revealing pulmonary arteriovenous malformations on chest CT scan.