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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cryptogenic stroke is a diagnosis of exclusion. These are strokes that occur in people who are usually less than 55 years old, without an identifiable cause. Our sensitivity to these events has been heightened because of the new definitions of a transient ischemic attack. Transient ischemic attack (TIA) is a clinical diagnosis of a neurologic deficit without MRI abnormalities: if there is an MRI abnormality, whether or not that person is symptomatic, it is now defined as a stroke. With these new definitions, and the sensitivity of MRI, we are seeing more cryptogenic strokes. It has been hypothesized that many cryptogenic strokes are caused by small emboli that travel from the legs to the right atrium; during straining (such as a Valsalva maneuver) these emboli can go across a PFO into the left atrium and then travel to the brain, producing a stroke. The problem is that these are very small emboli, approximately 1 to 3 mm, and we can't actually show these small emboli crossing from right to left. However, large emboli have been observed by echocardiography to be trapped in the PFO. So the diagnosis of cryptogenic stroke is a diagnosis of exclusion that is impossible to verify. What is the scope of the problem? Of the 700,000 strokes per year in the United States, 80% of them are ischemic, and 20% of those are defined as cryptogenic. The prevalence of PFO among this cryptogenic stroke population is about 40% to 50%; in the general population, it's only about 20%. Current estimates are that somewhere between 30,000 and 60,000 strokes per year in the U.S. are caused by paradoxical embolism through a PFO. There are some other fascinating associations: scuba divers with PFOs are more susceptible to decompression illness. Platypnea-orthodeoxia is a condition of desaturation that occurs when you're standing up but not when you're lying down; these patients are quite symptomatic, with arterial saturations in the low 80s. They also frequently have PFOs; if you close the PFO, the arterial desaturation is alleviated. Fat emboli during orthopedic surgery or air emboli during neurosurgery may also travel through the venous system. If you don't have a PFO, the fat or the air is trapped in the lungs and doesn't cause much of a problem unless it's massive; but if you have a PFO, then the embolus can go from right to left atrium up to the brain, with devastating neurologic consequences.
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PMID:Does patent foramen ovale promote cryptogenic stroke and migraine headache? 1639 19

Platypnea-orthodeoxia is a syndrome characterized by dyspnea and hypoxemia in orthostatism relieved by supine position. This phenomenon is frequently associated with interatrial communication, mainly patent foramen ovale. The association of platypnea-orthodeoxia syndrome with recurrent stroke and patent foramen ovale is extremely uncommon. A 73-year-old woman experienced recurrent attacks of dyspnea after an ischemic stroke. Arterial blood gas analysis changes in upright and supine position confirmed the diagnosis of platypnea-orthodeoxia syndrome. Contrast-enhanced transthoracic echocardiography showed patent foramen ovale with atrial septal aneurysm and right-to-left shunt. Percutaneous closure of patent foramen ovale led to stabilization of blood oxygen saturation and resolution of dyspnea. Platypnea-orthodeoxia syndrome should be considered in patients with stroke and unexplained dyspnea. The diagnosis could lead to correction of an unknown cardiac defect and of potential risk factor for stroke.
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PMID:Unexplained dyspnea in an old patient with recurrent stroke: platypnea-orthodeoxia syndrome and evidence of patent foramen ovale. 1987 92

Platypnea-orthodeoxia is a rare syndrome characterized by dyspnea and deoxygenation induced by a change to a sitting or standing from a recumbent position. It is the result of posturally accentuated intracardiac or pulmonary right-to-left shunt leading to arterial oxygen desaturation. Only few cases of platypnea-orthodeoxia syndrome are reported in the literature and the association between stroke and platypnea-orthodeoxia syndrome with evidence of patent foramen ovale is extremely rare. We describe the case of a 67-year-old female admitted to our Rehabilitation Unit for disabling basilar stroke due to paradoxical embolism from patent foramen ovale that during the first days of rehabilitation showed signs and symptoms of platypnea-orthodeoxia syndrome. To remove a life-threatening condition for the patient and in order to develop the normal rehabilitation project, that was stopped by the platypnea-orthodeoxia syndrome, the patient fastly underwent to percutaneous closure of patent foramen ovale. The stabilization of oxygen arterial saturation with postural changes and the disappearance of symptoms of POS allowed to develop the rehabilitation project with progressive neurological improvement.
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PMID:Can patent foramen ovale affect rehabilitation? The uncommon association of platypnea-orthodeoxia syndrome and stroke. 2146 77

Platypnea-orthodeoxia syndrome (POS) is a rare clinical disorder characterized by dyspnea caused by the upright position and relieved at recumbent position. Few cases of POS and stroke were reported in literature, and the association between stroke and POS with evidence of patent foramen ovale (PFO) is rare. Stroke may occur in patients with cardiac shunt who undergo contrast echocardiography. We present a patient with POS who experienced transitory ischemic attack (TIA) most likely caused by injection of agitated saline microbubbles during screen for PFO. No case report of TIA/stroke during contrast echocardiography in patients with POS has previously been published.
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PMID:TIA Caused by Contrast Echocardiography in Patient with Platypnea-Orthodeoxia. 2675 48

A 68-year-old woman presented with progressive and severe effort-related dyspnea. Her history included an ischemic stroke at age 43. Routine exams were normal. Cardiopulmonary exercise testing (CPET) showed a reduction in PaO2 from 11.8 kPa to 4.8 kPa. Repeated CPET with 100 % inhaled O2 improved the drop in PaO2 marginally. Transesophageal echocardiography revealed a shunt from right to left through a patent foramen ovale (PFO). A right heart catheterization showed normal pressures and no signs of intrapulmonary shunting. The PFO was closed percutaneously and the patient's symptoms resolved almost completely. Platypnea-orthodeoxia syndrome is an uncommon disorder where the pathophysiological mechanisms include a right-to-left shunt, either intracardiac or pulmonary. The most common intracardiac shunt related to the syndrome is a PFO. Platypnea-orthodeoxia syndrome, although rare, merits our attention, since it is often easily treatable. The key finding is desaturation on standing up.
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PMID:[Platypnea-orthodeoxia syndrome: a neglected cause of dyspnea?] 3239 Jan 26