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Paper text:
hemodynamic failure is a relatively rare cause of transient ischemic attacks ( tia ) . in these cases
, tia may be triggered by a change from the supine into the upright position in patients with compromised hemispheric perfusion and exhausted cerebral vasoreactivity following severe obstruction of the internal carotid artery ( ica ) .
typically , tia may present with repetitive shaking movements of the effected limbs , which is referred to as limb - shaking tia . in this report
, we describe the case of a patient with highly frequent tia as a consequence of severely compromised left hemispheric perfusion .
three years before presentation , a routine assessment of the brain - supplying arteries had led to the diagnosis of left ica occlusion . on admission ,
the episodes affected the right arm and leg and mainly consisted of involuntary non - rhythmic shaking movements , limb weakness and speech problems that she referred to as a  mental block. sometimes the mental block was the leading symptom .
she reported that the episodes mainly occurred after standing up from a supine position or when walking .
we observed these episodes on several occasions after the patient had been lying and was then asked to sit or stand up ( online suppl .
an ultrasound examination revealed subtotal stenosis of the left extracranial ica with extensive lumen narrowing in the whole extracranial segment .
transtemporal insonation demonstrated postocclusive flow in the left middle cerebral artery ( mca ) . additionally , hyperventilation apnea testing indicated an exhausted cerebrovascular reserve ( fig .
1 ) . moving the patient from a supine to a sitting position further resulted in a marked decline of mca flow velocities . at the same time , the patient experienced typical limb - shaking symptoms , which resolved after 2 min .
the a1 segment of the left anterior cerebral artery ( aca ) was not detectable despite good insonation conditions , indicating poor collateral quality .
high velocities were found in the right a1 and the left p2 segments , demonstrating collateral flow via leptomeningeal anastomoses .
repeated eeg tracing during the course of the patient 's hospital stay revealed discrete focal theta slowing over the left hemisphere without epileptiform phenomena . an antiepileptic treatment attempt with valproic acid
the diagnosis of limb - shaking tia due to compromised left hemispheric perfusion was established .
since the patient had experienced the symptoms for several years on a much less frequent basis , acute heart failure was thought to be the cause of the cerebral hemodynamic deterioration .
best medical treatment of her chronic heart disease resulted in an only moderate improvement of her left ventricular ejection fraction from 23 to 35% ( measured by echocardiography ) , which , however , did not result in a lasting neurological improvement .
as a consequence , the patient was confined to bed and revascularization of the left ica territory was discussed . due to the small caliber of the peripheral arterial branches
, extra - intracranial bypass surgery was thought to result in a primarily insufficient bypass and was therefore discarded .
finally , angioplasty and stenting of the proximal ica were performed as a treatment attempt .
the stent could be placed without complications and angioplasty was performed within the whole cervical segment of the ica . however , although the stent was sufficiently expandable , there was only a moderate improvement of the distal lumen narrowing ( fig .
it was now clear that the distal ica was nearly occluded and , therefore , no possibility for a further recanalization could be found .
ultrasound controls up to 3 weeks later showed unchanged hemodynamics with persisting pendular flow patterns within the ica . at that point , the patient rejected further invasive treatment and was therefore discharged to rehabilitation in an only slightly improved clinical status .
we report a patient with severe left cerebral hemodynamic insufficiency as a consequence of subtotal ica stenosis and poor collateral function .
intracranial doppler analysis demonstrated insufficiency of the main collateral pathways , a finding that has previously been associated with a state of maximal hemodynamic compromise .
the severity of our findings is further underlined by the exhausted vasomotor reactivity and by the documentation of a severely pathological reduction of mca flow velocities in orthostatic situations ( fig .
limb - shaking tia was repeatedly triggered by a change of position from supine to sitting or standing . according to this observation
, limb - shaking tia may be considered as a vascular paroxysmal dyskinesia , triggered by an orthostatically induced decrease of cerebral blood flow in already critically hypoperfused arterial territories .
bogousslavsky and regli   found focal limb - shaking symptoms in 12% of 51 patients with infarcts in watershed cerebral territories .
treatment of low - flow tia focuses on measures to improve cerebral blood flow . in our patient
, severe cardiac insufficiency may have contributed to the exacerbation of tia frequency , because maximally dilated arteries are unable to increase their capacity in stress situations such as decreased cardiac output . however , medical treatment only moderately improved cardiac output and did not result in a neurological improvement .
extra - intracranial bypass surgery as a treatment option in this high - risk patient group has been shown to improve symptoms in a series of 5 patients who underwent the procedure .
unfortunately , carotid stenting did not result in significant cerebral reperfusion due to the irreversible narrowing of the distal ica in the 3-week follow - up period .
epilepsy as a potential differential diagnosis was ruled out due to the presenting symptoms and the circumstances of their manifestation , the complementary imaging and eeg findings , and the missing response to antiepileptic treatment . in a previous report of 4 limb - shaking tia cases , focal delta slowing in eeg , without noteworthy structural lesions on imaging , was found .
the authors discuss a structural / eeg mismatch attributable to cerebral hypoperfusion . in our case , left hemispheric theta slowing may have been a consequence of the documented white matter lesions . retrospectively , in this context , it would have been an interesting task to compare the hemodynamic changes in the mca with eeg abnormalities during change of position from supine to sitting .
it may occur in patients with occlusive disease of major brain - supplying arteries and poor collateral conditions .
transcranial doppler is well suited to document hemodynamic instability from exhausted vasomotor reactivity and orthostatic decrease of mca blood supply .
limb - shaking transient ischemic attacks ( tia ) may occur in patients with insufficient brain perfusion due to an underlying occlusive disease . 
 we present the case of a 64-year - old patient who suffered from repetitive tia presenting with shaking movements of the right - sided extremities and accompanying speech arrest . 
 symptoms are documented in the online supplementary video ( www.karger.com/doi/10.1159/000327683 ) . 
 these episodes were frequently triggered in orthostatic situations . 
 the diagnosis of limb - shaking tia was established . 
 the diagnostic workup revealed pseudo - occlusion of the left internal carotid artery , a poor intracranial collateral status and , as a consequence , an exhausted vasomotor reserve capacity . at ultrasound examination , symptoms were provoked by a change of the patient 's position from supine to sitting . during evolvement of symptoms , a dramatic decrease of flow velocities in the left middle cerebral artery was observed . 
 this case thus documents the magnitude and dynamics of perfusion failure in a rare manifestation of cerebral ischemic disease .