domingo, 8 de marzo de 2009

Mielinolisis central pontina

La mielinolisis central pontina (MCP) es una entidad caracterizada por la destrucción de mielina en la base de la protuberancia, generalmente asociada con enolismo, corrección rápida
de la hiponatremia y otras alteraciones electrolíticas. Se describe la clínica, factores etiopatogénicos, neuroimagen y evolución de una serie de pacientes con diagnóstico de mielinolisis central pontina/extrapontina (MCP/E).
Se ha publicado en español una serie en Neurología 166 2009;24(3):165-169

Dissecting Aneurysm of the Posterior Cerebral Artery

A 43-year-old man presented with acute-onset hemianesthesia involving the right arm, the right leg, and the right side of the face. Six weeks earlier, he had a moderate occipital headache that lasted for 3 days. Diffusion-weighted magnetic resonance imaging (MRI) of the brain showed a thalamic lesion of restricted diffusion on the left side (Panel A, arrow), which was consistent with acute posterior choroidal-artery infarction. T2-weighted MRI scans, a magnetic resonance angiogram, and a computed tomographic angiogram (Panels B, C, and D, respectively) revealed a dilatation of the left posterior cerebral artery, with a double lumen — that is, a true circulating lumen (Panels B, C, and D, lower arrows) and a false noncirculating lumen (Panels B, C, and D, upper arrows), divided by an intimal flap (Panel B, arrowheads), suggesting a dissecting aneurysm. Angiography confirmed an aneurysm of the posterior cerebral artery (Panel E, arrows). The patient reported no specific risk factor (e.g., trauma) for arterial dissection. Uncomplicated occlusion of the aneurysm and the parent posterior cerebral artery was achieved with endovascular coils (Panel F). A few weeks later, progressive, painless paresthesias occurred in the right hemibody, which were unchanged at a 1-year follow-up visit. Dissecting intracranial aneurysms typically present with infarction (due to stenosis or embolism) or subarachnoid hemorrhage (due to rupture). Treatment options include conservative management, administration of antiplatelet agents, anticoagulation, and surgical or endovascular intervention. Therapeutic occlusion of the posterior cerebral artery distal to the perforating arteries to the thalamus and brain stem is often well tolerated because of collateral circulation.
Renard D, Milhaud D. Images in clinical medicine. Dissecting aneurysm of the posterior cerebral artery. N Engl J Med. 2007 Dec 13;357(24):e27.

Occlusion and Reperfusion of the Middle Cerebral Artery

A 65-year-old woman with chronic atrial fibrillation was admitted for an elective exchange of an implanted defibrillator for idiopathic dilated cardiomyopathy. To facilitate this procedure, warfarin was withheld for 5 days. Before the procedure was performed, acute-onset right hemiparesis and expressive dysphasia developed. Urgent noncontrast computed tomography (CT) of the brain and CT angiography of the intracranial and extracranial arterial circulation confirmed an acute occlusion of the M2 segment of the middle cerebral artery, which was consistent with the presence of an embolus (Panel A, arrow). Ninety-five minutes after the onset of neurologic deficits, the patient was given a bolus dose and 1-hour infusion of tissue plasminogen activator. Repeat CT angiography, performed 25 hours after thrombolysis, showed reperfusion of the middle cerebral artery and cortical branches in the sylvian fissure on the left side (Panel B), which correlated with resolution of the neurologic deficits. Early administration of a thrombolytic agent is essential for optimal neurologic recovery. The patient has had no further neurologic symptoms, with no measurable deficit.

Ryan R, Brophy DP. Images in clinical medicine. Occlusion and reperfusion of the middle cerebral artery. N Engl J Med. 2007 Dec 13;357(24):2495.


Manual esencial para todos los que atienden urgencias neurológicas