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BRIEF COMMUNICATIONS: Bahram Mokri, J. Eric Ahlskog, Jimmy R. Fulgham, and Joseph Y. Matsumoto Syndrome resembling PSP after surgical repair of ascending aorta dissection or aneurysm Neurology 2004; 62: 971-973 [Abstract] [Full text] [PDF]

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Syndrome resembling PSP after surgical repair of ascending aorta dissection or aneurysm

James L. Bernat, M.D., Timothy G. Lukovits, M.D.   (20 April 2004)

Reply to Bernat and Leigh

Bahram Mokri, Bahram Mokri, J. Eric Ahlskog   (20 April 2004)

Syndrome resembling PSP after surgical repair of ascending aorta dissection or aneurysm

R. John Leigh, Robert L. Tomsak   (20 April 2004)

Syndrome resembling PSP after surgical repair of ascending aorta dissection or aneurysm 20 April 2004
James L. Bernat, M.D., Neurology Section, Dartmouth-Hitchcock Medical Center Neurology Section, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756, Timothy G. Lukovits, M.D. Send Correspondence to journal: Re: Syndrome resembling PSP after surgical repair of ascending aorta dissection or aneurysm bernat{at}dartmouth.edu James L. Bernat, M.D., et al.	Mokri et al described seven previously healthy middle-aged patients who developed a PSP-like syndrome following surgery on the ascending aorta. [1] They wondered if the aortic surgery somehow produced a delayed neurodegenerative process. We present two additional cases and suggest that the mechanism is the concurrent hypothermic circulatory arrest. Case 1: A 50-year-old previously healthy man underwent repair of an ascending aortic aneurysm and replacement of a bicuspid aortic valve under hypothermic circulatory arrest at 18º C. for 33 minutes with retrograde cerebral perfusion. Within two weeks postoperatively, he lost the ability to make all saccadic eye movements, though he retained normal ocular tracking and reflex eye movements. Two months later, he developed progressive dysarthria, dysphagia, and gait instability. Brain MRI was normal. He remains disabled from his complete supranuclear gaze palsy with worsening symptoms five months later. Case 2: A 52-year old previously healthy man underwent repair of an ascending aortic dissection under hypothermic circulatory arrest at 15º C. for 41 minutes with retrograde cerebral perfusion. He had nearly absent saccadic eye movements and gait ataxia. Several months later, he developed increased dysarthria and ataxia. MRI showed only a small infarction in the left centrum semiovale. A neurologist diagnosed progressive supranuclear palsy based on his marked supranuclear gaze palsy and pseudobulbar signs. He progressed for several months and then stabilized with principal disability from complete supranuclear gaze palsy. Both patients fit the syndrome described by Mokri et al. [1] We suspect that the hypothermic circulatory arrest during which the surgeries were performed is more likely responsible for causing the neurological syndromes than the aortic surgery. Surgery on the ascending aorta requires aortic arch clamping in a location that interferes with brain circulation. The procedures are commonly performed under hypothermic circulatory arrest to prevent ischemic brain damage resulting from aortic clamping. We presume that all the patients in the Mokri et al series had their aortic surgeries performed under hypothermic circulatory arrest. Syndromes of basal ganglia damage resulting from hypothermic circulatory arrest have been described in children [2-4] and shown to be caused by selective damage to the globus pallidus. [5] Affected children developed oro-facial-linguial dyskinesias and choreoathetotic limb movements a few days after surgery and many had supranuclear ophthalmoplegia. Hypothermia was implicated because dyskinesias were rarely noted when cardiopulmonary bypass was performed without hypothermia. There was a relationship between the duration and degree of hypothermia and the severity of the dyskineasis. [4] We hypothesize that in our patients and those of Mokri et al, neuronal damage was caused by hypothermic circulatory arrest producing a syndrome of supranuclear gaze palsy, dysarthria, dysphagia, and gait ataxia superficially resembling PSP. References 1. Mokri B, Ahlskog JE, Fulgham JR, Matsumoto JY. Syndrome resembling PSP after surgical repair of ascending aorta dissection or aneurysm. Neurology 2004;62:971-3. 2. Wical BS, Tomasi LG. A distinctive neurologic syndrome after inducing profound hypothermia. Pediatr Neurol 1990;6:202-5. 3. Robinson RO, Samuels M, Pohl KR. Choreic syndrome after cardiac surgery. Arch Dis Child 1988;63:1466-9. 4. Huntley DT, al-Mateen M, Menkes JH. Unusual dyskinesia complicating cardiopulmonary bypass surgery. Dev Med Child Neurology 1993;35:631-6. 5. Kupsky WJ, Drozd MA, Barlow CF. Selective injury of the globus pallidus in children with post-cardiac surgery choreic syndrome. Dev Med Child Neurology 1995;37:135-44.
Reply to Bernat and Leigh 20 April 2004
Bahram Mokri, Mayo Clinic Rochester 200 First Street SW; Rochester, MN 55905, Bahram Mokri, J. Eric Ahlskog Send Correspondence to journal: Re: Reply to Bernat and Leigh bmokri{at}mayo.edu Bahram Mokri, et al.	We agree with Dr. Bernat that the two patients reported are examples of the syndrome that we described. Undoubtedly, more cases will be reported. The exact mechanism of this biphasic disorder, which is likely self-limiting, has to be worked out. Peri-operative factors, including hypoxemic stress and hypothermia (whether directly or by prolonging the period of hypoxemia) on one hand, and regional tissue vulnerability and individual susceptibility on the other hand should be considered in the future studies now that the dialogue on this disorder has been started. We suspect that the phenotypic presentation will prove to show variability. We also thank Dr. Leigh for this interest in our article. Supranuclear oculomotor palsy was only a part of this biphasic syndrome. The latent phase that often resembles PSP had components of pronounced gait unsteadiness and dysarthria, leaving the patient with substantial neurologic disability, over shadowing the supranuclear oculomotor palsy. We did not see evidence of infarction or ischemic change in the brainstem on any of the MRI scans. We agree with Dr. Leigh that pathogenesis of this disorder should be further investigated. We do not believe that this syndrome is a consequence of cerebral or brainstem infarcts.
Syndrome resembling PSP after surgical repair of ascending aorta dissection or aneurysm 20 April 2004
R. John Leigh, Case Western Reserve University 11100 Euclid Avenue, Cleveland, Ohio 44106-5040, Robert L. Tomsak Send Correspondence to journal: Re: Syndrome resembling PSP after surgical repair of ascending aorta dissection or aneurysm rjl4{at}case.edu R. John Leigh, et al.	We read with interest the report by Mokri et al [1] who described seven patients with a disorder of voluntary gaze following cardiac surgery. They reported that their patients showed “vertical supranuclear gaze palsy”, gait unsteadiness, and dysarthria. Interestingly, their patients showed progression of their disability over several months. MRI scans showed no evidence of acute infarction. In prior studies, we have reported three patients with voluntary gaze palsies following cardiac surgery, [2] including clinical-pathological correlations in one. [3] Assuming that this syndrome is vascular in origin, then two hypotheses could be offered to account for the disturbance of eye movements. One hypothesis is that such patients have suffered bihemispheric infarction affecting the frontal and parietal eye fields (which lie in the watershed between middle and anterior cerebral artery supplies). A prediction of this hypothesis is that all voluntary eye movements (saccades, pursuit, vergence) will be impaired, but reflexive eye movements, such as slow and quick phases of vestibular and optokinetic nystagmus will be preserved. This is reported to be the case in patients with ocular motor apraxia due to bihemispheric frontoparietal disease. [4] A second hypothesis is that these cardiac patients suffer focal, paramedian brainstem infarction, specifically affecting the neuronal machinery for generating saccades. [5] This hypothesis predicts that all rapid eye movements (voluntary saccades and quick-phases of nystagmus) will be affected, but other classes of eye movements, such as pursuit and vestibular movements will be preserved. The patients that we described all conformed to the second prediction, with a selective palsy of saccades and quick phases (vertical, horizontal, or both) but with preservation of other types of eye movements. [2,3] A video clip from the study of Mokri et al appears to show a patient with impaired vertical and horizontal voluntary saccades, but with some preservation of smooth-pursuit and vestibular eye movements. In one patient who died several weeks after surgery, we were able to demonstrate that the selective saccadic defects were due to paramedian pontine brainstem damage. [3] Although patients may differ, we have yet to study a patient with this syndrome with voluntary gaze disturbance that could be ascribed to hemispheric infarction. Dr. Mokri et al raise another interesting issue that the syndrome appears to progress with time which we have also encountered. [2] Brainstem infarction that affects the inferior olivary nucleus causes, after a delay of weeks to months, the syndrome of oculopalatal myoclonus (tremor). [4] Perhaps a similar mechanism, which is incompletely understood, is operating in these patients who have undergone cardiac surgery. Finally, Mokri et al. suggest that “this complication is fairly rare” following cardiac surgery. In our experience, surgeons often do not recognize it, and patients’ complaints are sometime dismissed as psychogenic. Wider recognition of this complication of cardiac surgery should lead to better understanding of its pathogenesis and development of rehabilitation techniques which, at present, have little therapeutic effect. [2] References 1. Mokri B, Ahlskog E, Fulgham JR, Matsumoto JY. Syndrome resembling PSP after surgical repair of ascending aorta dissection or aneurysm. Neurology 2004; 62: 971-973. 2. Tomsak RL, Volpe BT, Stahl JS, Leigh RJ. Saccadic palsy after cardiac surgery: visual disability and rehabilitation. Ann N Y Acad Sci. 2002;956:430-3. 3. Hanson MR, Hamid MA, Tomsak RL, Chou SM and Leigh RJ: Selective saccadic palsy due to pontine lesions: clinical, physiological and pathological correlations. Ann. Neurol. 20:209-217, 1986. 4. Leigh RJ and Zee DS: The Neurology of Eye Movements, ed. 3. (Book/CD-ROM) Oxford1999. 5. Leigh RJ, Kennard C. Using saccades as a research tool in clinical neurosciences. Brain. 2004; 127: 1-18.