C. Alan Anderson

Asymptomatic pontine lesions found by magnetic resonance imaging: Are they central pontine myelinolysis?

Clinicians occasionally receive radiographic reports noting pontine lesions in their patients who have undergone magnetic resonance imaging (MRI) for symptoms not referable to the pons. Based on these relatively isolated lesions, patients may receive the presumptive radiographic diagnosis of central pontine myelinolysis (CPM). Review of our MRI database from the last five years identified twelve such patients with hyperintense pontine lesions on T2-weighted scans which were out of proportion to supratentorial white matter disease processes and unexplained by the remainder of their radiographic studies. In an attempt to further clarify whether these findings were more consistent with CPM or some other process, we reviewed these patients clinical records with particular attention to electrolyte disturbances, alcoholism, liver disease and hypertension. We also compared the MRI studies from these twelve patients with four MRI scans from patients with clinically diagnosed CPM and with eight post-mortem MRI scans on autopsy-proven asymptomatic CPM. By comparing pre- and post-mortem scans, five of the twelve unknown pontine lesions were felt to be too large to represent asymptomatic CPM. Five were thought to be incompatible with CPM based on shape and/or discohesiveness; one of these came to autopsy and showed cerebral and pontine ischemic rarefaction, not CPM. Only two of these twelve cases were felt to be asymptomatic or mildly symptomatic CPM, but have not come to autopsy. We conclude that pontine lesions found incidentally on MRI scans are a heterogeneous group, many of which are more consistent with pontine ischemic rarefaction than with asymptomatic CPM.

Antiphospholipid antibodies are common in patients referred for percutaneous patent foramen ovale closure

Very little is known about any interaction between patent foramen ovale (PFO) and various hypercoagulable disorders that have been associated with cryptogenic stroke. Percutaneous PFO closure for secondary prevention of paradoxical thromboembolization is receiving increasing attention. Hypercoagulability may affect the potential risks and expected benefits of percutaneous PFO closure. Consecutive patients undergoing percutaneous PFO closure at a single center were screened for the presence of antiphospholipid antibodies, elevated lipoprotein(a), hyperhomocysteinemia, and dysfibrinogenemia. Sixteen of 34 patients (47%) with complete arterial hypercoagulability screening had laboratory evidence of arterial hypercoagulability. Thirteen of these patients (38%) had antiphospholipid antibodies. Antiphospholipid antibodies appear to be common in patients referred for percutaneous PFO closure for secondary prevention of systemic thromboembolic events. Thorough testing based on established recommendations is warranted. Further studies are needed regarding the interaction between PFO and various hypercoagulable disorders that have been associated with cryptogenic stroke. Catheter Cardiovasc Interv 2004;61:123–127.

Non-traumatic carotid dissection and stroke associated with anti-phospholipid antibody syndrome: report of a case and review of the literature.

Young adults with stroke frequently do not have any of the traditional risk factors associated with stroke, prompting a search for other mechanical and hypercoagulable causes. The authors report a young man presenting with stroke and subsequently diagnosed with a carotid dissection. Recurrent strokes while on heparin prompted a search for a second etiology and the patient was found to have antiphospholipid antibody syndrome. Although these conditions may be coincidental, we propose that their interaction was significant in this patients presentation. Other reports of this association will also be reviewed.