primary orthostatic cerebralischaemia · stark, wodak r l commoncarotid stenosed fig 1 angiogram...

Journal of Neurology, Neurosurgery, and Psychiatry 1983;46:883-891

Primary orthostatic cerebral ischaemiaRICHARD J STARK, JACK WODAK

From the Neurology Unit, Alfred Hospital, Prahran, Victoria, Australia

SUMMARY Four patients with "primary orthostatic cerebral ischaemia" are described. They com-plained of dizziness, light-headedness or syncope on standing. None had a significant fall in hissystemic blood pressure on assuming the erect posture. Each had bruits over the major neckvessels or absent pulses. Angiography showed widespread narrowing or occlusion of the cervicalblood vessels which supply the brain. Carotid endarterectomy relieved the patients' symptomsand also reduced the fall in retinal artery pressures on standing noted preoperatively. Theclinician who is not aware of the poorly documented syndrome of "primary orthostatic cerebralischaemia" may fail to recognise that a patient's complaints are due to cerebrovascular disease forthey are strikingly different from those of classical transient ischaemic attacks.

Patients who complain of faintness and dizziness onstanding are probably suffering from posturalhypotension. We report four patients who wereseriously inconvenienced by such symptoms butwhose complaints could not be explained by a fall intheir blood pressure on standing. In fact their dis-ability remained unexplained until they developedthe typical focal neurological symptoms of transientcerebral ischaemia. We wish to draw attention to thefact that episodes of cerebral ischaemia may be pro-voked by changes in posture and may give rise togeneralised rather than focal complaints. We believesuch attacks indicate that changes in blood flowalone, without emboli, may be the basis for episodesof transient cerebral ischaemia. The recognition ofdistinct mechanisms for transient ischaemicattacks-cholesterol emboli, platelet emboli andvariations in blood flow without emboli-couldperhaps lead to more specific and effective treat-ment. We report four patients with transientischaemic symptoms due, we believe, to variations inblood flow.

Case reports

Case I (AH 446053)This 57-year-old woman had been diabetic for 25 yearsand a mild sensory neuropathy had been noted for some

Address for reprint requests: Dr J Wodak, Suite 4, 545 St KildaRoad, Melbourne, Victoria, Australia 3004.

Received 11 November 1982 and in revised form 22 May 1983.Accepted 2 June 1983

months. She had taken thyroxine for hypothyroidism formany years. Her husband reported that for about threeweeks before admission she was unable to walk properly;after walking a few yards she would start to drag the rightleg, complain of unsteadiness and have to sit down. Therewas no pain or sensory complaint. The patient had becomeprogressively less intellectually alert over many months buther husband believed that her vagueness was made worsewhen she adopted a standing position. The patient herselfwas a less informative historian commenting only that herlegs tended to give way. The blood pressure was 170/95mm Hg with the patient supine and 130/70 mm Hg stand-ing, in both arms. The fundi showed "blot" haemorrhages,microaneurysms and exudates typical of diabeticretinopathy. A soft ejection systolic murmur was heard atthe base of the heart. Separate loud systolic bruits wereaudible over both carotid and both subclavian arteries inthe neck. Bruits were heard over both femoral arteries; nopulses below the femoral could be palpated in either leg.Mental status examination revealed mild dementia. Cra-nial nerve examination, power, co-ordination and reflexeswere normal. Some inpairment of vibration and joint posi-tion sense was noted in both feet. Gait was unusual, with atendency to give way at the knees, to fall to the left and attimes for the right foot to drag. Examination of mentalstatus during walking was difficult because the patientrefused to answer questions while on her feet. Ophthal-modynamometry was not performed in the presence ofdiabetic retinopathy.1 Full blood examination, electro-cardiograph and serum biochemistry were normal (exceptfor elevated blood glucose). A chest radiograph was nor-mal, while skull radiographs showed some calcification inthe internal carotid arteries. Angiography (fig 1) revealedcomplete occlusion of the right internal carotid at its origin,some stenosis at the origin of the left common carotid, verymarked stenosis of the left internal carotid just beyond itsorigin and some stenosis of the left external carotid artery.

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Stark, Wodak

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L Common carotid stenosed

Fig 1 Angiogram (a) and line drawing (b) of case 1.

The right vertebral artery was narrowed at its origin. Theleft subclavin artery contained a plaque proximal to theorigin of the left vertebral which was a small vessel and alsoshowed a segment of narrowing. Therefore of the fourneck vessels which supply the brain, only three remainedpatent and each of these was markedly stenosed.

Left carotid endarterectomy was performed. At opera-tion left carotid stump pressure was 48 mm Hg systolicwhile systolic blood pressure was 170 mm Hg. Routinedissection of the stenosing plaque was performed withoutcomplication. When seen two months later the patient andher relatives were delighted by her improvement. She waswalking more easily and for longer distances. Her relativesfelt that her mental state and concentration had markedlyimproved. Examination revealed postural hypotension asbefore. Her gait was now only slightly unsteady, with notendency to collapse at the knees. Her conversation wasmore lucid but tests of mental arithmetic were still per-formed poorly.

Case 2 (AH 470169)This 79-year-old woman had been treated for hyperten-sion for more than 40 years. Four weeks before admissionshe complained of some episodes of dizziness, generalmalaise and blurred vision while erect (but never while

sitting or supine). Her blood pressure was 250/120 mm Hg,and her hypotensive medication was adjusted. Her bloodpressure remained at around 180/90 mm Hg thereafter.However three weeks before admission the patient beganto complain of attacks of dizziness and malaise lasting forfive minutes and accompanied by numbness and weaknessof the left side of the face and limbs. All the attacks occur-red soon after the patient stood up and forced her to sitagain. She experienced such episodes about three timesdaily although more frequently an attempt to rise wasgreeted with light-headedness. Examination revealed analert old lady. Bruits were heard over both carotids andboth subclavian arteries in the neck. Mental abilities werequite normal except for some difficulty with arithmetic.Neurological examination and gait were also normalalthough the patient took a moment to become steady onher feet. Ophthalmodynamometry showed pressure of36/10 g (systolic/diastolic) in both eyes while the patientwas lying and only 12/5 g (both eyes) while the patient wassitting. At the same time, blood pressure was 170/100 mmHg in both arms with the patient supine, falling only to160/90 mm Hg when the patient stood up. Arch aortogra-phy revealed marked narrowing at the commencement ofboth internal carotid arteries (fig 2) as well as stenosis atthe origin of the left vertebral artery and some atheroma



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Primary orthostatic cerebral ischaemia

near the origin of both subclavian arteries. Dynamicisotope brain scan showed reduced flow to the right cere-bral hemisphere. Supra-orbital artery Doppler flow studiesrevealed no predominant direction of flow on the left butdefinitely abnormal flow on the right into the skull.

Bilateral carotid endarterectomy was performed. Firstthe left carotid artery was exposed in the neck; while sys-temic blood pressure was 236 mm Hg (systolic) (155 mmHg (mean) ), stump pressure in the left carotid was 34 mmHg (systolic) (29 mm Hg (mean)). Endarterectomy was

performed without a shunt. The right carotid artery wasthen explored; while systemic blood pressure was 228 mmHg (systolic) (147 mm Hg (mean) ), stump pressure was 84mm Hg (systolic) (68 mm Hg (mean) ). Again endarterec-tomy was performed without a shunt. Post-operatively thepatient was markedly improved. She could stand and walkwithout any dizziness and when reviewed a month laterhad no recurrence of focal ischaemic episodes. Ophthal-modynamometry post-operatively showed diastolic pres-sures while the patient was seated of 35 g in the right eye

Internal carotidstenosed

R Externalcarotid stenosed

Plaques ininnorninateL Common |:carotidaind subuclavian

Fig 2 Angiogram (a) and line drawing (b) ofcase 2.

and 20 g in the left, which were considerably higher thanthose measured pre-operatively.

Case 3 (AH 457907)This 71-year-old retired male school teacher had been tre-ated for hypertension and mild diabetes for several years.He presented because of two episodes, each resolvingcompletely after 20 minutes, of blindness of the left eye.However, his family reported, and he agreed, that his intel-lectual function had been deteriorating over the past twoor three years. For several months he had suffered fromintermittent distressing episodes which occurred only whenhe was standing; during these he would feel "vague" andhis legs would "go funny" so that he felt he must sit down.He had not collapsed during such an attack. Examinationrevealed a loquacious elderly man with marked comealarcus. Blood pressure was 130/70 mm Hg lying and stand-ing in both arms. The vascular system was extremely dis-eased; a soft systolic ejection murmur in the heart radiatedto the right carotid and subclavian arteries but much

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Stark, Wodak

0Retrograde filling of

/o I internal and externalzX carot id

R Internal carotidoccluded

L CommonPortion outlirangiogorm sh

Stenosis ofboth vertebrals

L shown on another view

Fig 3 Angiogram (a) and line drawing (b) of case 3. Seealso fig 4.

X carotid

louder, more proldnged, separate bruits were audible over

the left carotid and subclavian arteries. All of these vesselswere easily palpable. Pulses could not be felt in the rightpopliteal fossa or below and bruits were audible over bothfemoral arteries. The right superficial temporal and occipi-tal arteries were strikingly prominent, pulsatile and nottender. Neurological examination was quite normal. Skulland chest radiographs, full blood and bio-chemical exami-nations were normal. Electro-cardiogram showed firstdegree atrio-ventricular block and right bundle branchblock. Arch aortogram (fig 3) revealed complete occlusionof the right internal carotid artery at its origin and failureof the left common carotid to fill higher than 10 cm from itsorigin; the left internal and external carotid filled, appar-ently retrogradely by collaterals, so that the left carotidbifurcation was patent while the common carotid just pro-ximal to this region was not. Additionally there were sten-oses at the origin of both vertebral arteries and a flatatheromatous plaque on the left subclavian artery.The patient was commenced on Warfarin for his two

attacks of amaurosis fugax. The cause of his attacks ofvagueness and leg weakness was not defined. Some eightmonths later the patient returned for review. There had

been no more attacks of transient blindness. However, hispostural symptoms had become more troublesome; whenstanding (particularly after rising quickly) he frequentlybecame unstable and had to sit. On a few occasions he hadactually collapsed to the floor, perhaps with momentaryloss of consciousness. Examination was unchanged. Oph-thalmodynamometry showed pressures of 42/24 g(systolic/diastolic) in the right eye and 30/12 g in the lefteye while lying which fell to 24/18 g and 18/8 g respectivelywhen the patient stood up. The systemic blood pressurewas 130/70 mm Hg without a postural change.

Because of the increasing postural symptoms it wasagreed that surgery should be reconsidered. Aortic archangiogram was unchanged. A selective injection into theleft common carotid stump revealed that the vessel was infact patent to a point just below the birfurcation (fig 4).Doppler studies of supraorbital vessels revealed reverseflow in the right orbit (with prominent flow into the orbitfrom the face) and equivocal results on the left.

It was felt that surgery on the right carotid system wasnot feasible but that left common carotid endarterectomymight be possible and could lead to improved cerebral per-fusion. At operation, endarterectomy of common, internal

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Fig 4 Selective left common cartoid injection in case 3showing patent vessel extending almost to level ofbifurcation. Compare with fig 3.

and external carotid arteries in the region of the bifurca-tion was performed. Stump pressure was 68 mm Hg (sys-tolic) and 51 mm Hg (mean) while systemic blood pressurewas 150 mm Hg systolic. Postoperatively the patient'scourse was complicated. He awoke alert but with mild leftarm weakness and remained stable for the next three days.He then became less mentally alert and his left arm becameweaker. The next day focal fitting involving the right armand leg occurred and was controlled with anti-convulsants.Treatment with heparin was commenced. Two days laterhe gradually became less alert and passed into coma. Hisonly response was some facial grimacing on painful stimu-lation. He was generally hypertonic with bilateral Babinskisigns. His blood pressure was 140/80 mm Hg but his temp-erature was 38°C. Cultures of blood and urine were nega-

tive. Cerebrospinal fluid analysis was normal. Computedtomography of the brain showed no abnormality. Isotopebrain scan showed no flow of isotope up the right intemalcarotid artery while the left internal carotid artery flowappeared quite normal. Static scans were normal. The

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patient's dramatic decline was therefore not readilyexplained. Antibiotics and dexamethasone were given.After being comatose and apparently moribund for threedays the patient improved over a day or two in an equallyinexplicable fashion. He was as alert as before the opera-tion and had no focal neurologiccal signs. When reviewedtwo months postoperatively he was alert and declared theoperation a "great success" as his postural symptoms hadnow completely disappeared. Ophthalmodynamometrynow showed remarkable improvement with systolic pres-sure of 125 g (supine) and 115 g (standing) recorded inboth eyes by the indirect method.2

Case 4 (AH 474729)A 58-year-old man had a 16 year history of insulin depen-dent diabetes and a six month history of hypertension. Hehad a nine month history of frequent episodes duringwhich his "legs went to jelly", his vision became blurred,he complained of "dizziness" and he became mentally dul-led. He described these attacks as a "semi-blackout", butcould recall falling to the ground only twice. On the otheroccasions the attacks settled, usually within two or threeminutes, when he lay down or put his head down. Theattacks were almost invariably caused by standing up froma chair, although a rare episode occurred while he wasseated in front of the television after a heavy meal. On twooccasions he actually fainted while standing and remainedunconscious for about 5 minutes. After the second suchepisode he was noted to have an ataxic gait and slurredspeech and complained of pins and needles in both feet.These findings, which persisted for two hours, led to hisreferral for investigation of his cerebro-vascular status.The patient was confident that these attacks differed fromthe occasional hypoglycaemic attacks he had suffered overthe years. He could not recall any attacks related to usinghis right arm. Examination showed a weak delayed rightradial pulse. Blood pressures were measured with thepatient supine as 100/85 mm Hg in the right arm and 140/85 mm Hg in the left arm and did not change when thepatient sat or stood. Bruits were audible over both carotidarteries and the right subclavian and both femoral arteries.Apart from a moderate degree of ataxia present bilaterally,neurological examination was normal. Routine blood testswere normal. Subraorbital artery flow studies using Dop-pler technique showed flow from the forehead into theorbit on the left (the reverse of the normal pattern) butnormal direction of flow on the right. Arch aortography(fig 5) showed very severe stenosis of the left internalcorotid artery, marked atheroma at the bifurcation of theright common carotid artery with moderate stenosis at theorigin of the right internal carotid artery. In addition theright subclavian artery was almost completely occludedover its proximal 3 cm and late filling from above the rightvertebral artery (which arose distal to the stenosis) wasdemonstrated. The left vertebral artery was a large calibrevessel which showed some kinking by a vertebralosteophyte; this varied in severity but in some filmsappeared quite marked.The left carotid artery was explored and severe stenosis

confirmed. Systolic stump pressure was 80 mm Hg whilethe systemic systolic blood pressure was 190 mm Hg.Routine internal carotid endarterectomy was completed



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0L I

RCommon carotid L Ibiturcation atherma carR Internal carotid steno

Fig 5 Angiogram (a) and line drawing (b) of case 4.

without mishap. The patient returned home and over thenext six months found that the attacks of postural faintnesswere rather less frequent but were certainly not completelyabolished. They were similar in nature to those before hisoperation. He now admitted to some impairment in mem-ory and concentration, which he felt was not altered by theendarterectomy. He was seen during an attack at this stage.He became vague shortly after standing and was unable toanswer sensibly. He clumsily leaned back onto his bed andafter two minutes lying semi recumbent was back to nor-

mal. Pulse rhythm, blood pressure and blood glucose were

all normal during the attack. Brachial blood pressures weresimilar to those during his earlier admission and again didnot alter when he stood. Vascular and neurological exami-nations were also unchanged. Ophthalmodynamometry bythe indirect method yielded systolic pressures in the lefteye of 125 g falling to 110 g and in the right eye of 100 g

falling to 35 g with the patient lying and sitting respec-tively; he could not stand long enough to be examined.

Angiography showed that the left internal carortid was

patent although the lumen diameter was.only 50% of nor-

mal. This was a considerable improvement on the initialsituation. Otherwise there had been no change from theprevious study.

Six months after the left carotid endarterectomy theright carotid artery was explored. A moderate stenosis wasfound. Systolic stump pressure was 96 mm Hg while sys-temic blood pressure was 204 mm Hg (systolic). A routineendarterectomy was performed. Postoperatively thepatient was markedly improved. He was able to walk aboutand even stand up suddenly without faintness. Ophthal-modynamometry confirmed an improved right retinalartery pressure; systolic pressures measured indirectlywere 125 g, 105 g, and 90 g in the right eye with the patientsupine, sitting and standing respectively. Pressures in theleft eye were unchanged. The patient was reviewed twomonths after right carotid endarterectomy and no longerexperienced any symptoms on standing.

Internalrotid stenosed

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Primary orthostatic cerebral ischaemiaDiscussion

We have become accustomed to thinking of trans-ient ischaemic attacks as occurring in the carotid andvertebrobasilar territories. The four patientsreported here were referred only when theydeveloped focal neurological symptoms attributableto one or other of these vascular territories. Yet, atthe time the focal attacks commenced, the patientswere already suffering from a condition which war-ranted treatment in its own right. In each case, itpassed unrecognised. We therefore wish to drawattention to the syndrome of "primary orthostaticcerebral ischaemia".Each patient's symptoms occurred shortly after

standing. They were characteristically and frustrat-ingly vague, but this vagueness is a part of the syn-drome. In two instances the relatives noticed thatthe patients were less coherent when standing. Wefound that one patient refused to answer questionswhilst on her feet. The behavioural changes, and theassociated symptoms, were, we believe, due to adrop in cerebral blood flow on standing that wassevere enough to impair performance. The othercomplaints were reminiscent of syncope; a sensationof dizziness and unsteadiness, a feeling of faintnessand a compulsion to sit down. In addition, somepatients also developed numbness or weakness intheir limbs. Walking rapidly became difficult, oreven impossible, but the patients recovered almostimmediately on sitting.

Physical examination suggested the presence ofwidespread arterial disease. There were invariablybruits over the carotid arteries and, sometimes, overthe femoral arteries as well. Most of the remaininglower limb pulses were impalpable. One patient hada diabetic retinopathy and in another, prominentbranches of the external carotid artery coursed overthe face and scalp to bypass an occluded internalcarotid artery. All of the patients were hypertensive;three were diabetic.Although the symptoms were reminiscent of a

faint, we were unable to attribute them to a fall inthe patient's blood pressure on standing. In only oneinstance was there an appreciable fall in the bloodpressure and this remained even when the patient'ssymptoms were relieved. However ophthalmo-dynamometry suggested that the pressure in thecerebral circulation dropped markedly on standing.When the patients had lost their symptoms afterarterial surgery the retinal artery pressures werehigher at rest and fell less when the patient stood.

Cerebral angiography demonstrated the wide-spread arterial disease that had been suspected clini-cally and showed that it was haemodynamically dis-ruptive. Every carotid artery was either occluded or

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very severely stenosed and atheromatous changeswere also present in the vertebral and subclavianarteries. The severity of the carotid stenoses wasconfirmed by intraarterial pressure measurementsduring surgery.We believe this syndrome differs significantly

from the transient ischaemic attacks described instandard texts.35 Our patients' symptoms were con-stantly related to standing, which would be mostunusual in orthodox transient ischaemic attacks. Thefaintness, unsteadiness and vagueness they experi-enced were more suggestive of syncope than thefocal neurological disturbances typically seen intransient ischaemic attacks. The attacks were notonly clinically distinct from orthodox transientischaemic attacks but probably also resulted from adifferent mechanism and this has clear implicationsfor their treatment. There is good reason to believethat the majority of transient ischaemic attacks aredue to emboli. Conglomerations of platelets orfragments of cholesterol have been seen duringattacks6 7 and demonstrated histologically. Alter-ations to the systemic circulation usually do not pro-duce the characteristically focal symptoms of trans-ient ischaemic attacks,8 so it seems reasonable toattribute them to a temporary disruption of a por-tion of the brain's circulation by emboli. It is thisbelief which provides the rationale for prescribinganticoagulants and antiplatelet drugs in the hope ofpreventing further transient ischaemic attacks andthe strokes which they may precede.The syndrome we are describing is, we suggest,

due to an overall, though transient, reduction incerebral bloodflow and does not result from emboli.Consequently anti-coagulants and anti-plateletdrugs could not be expected to prevent such symp-toms and, indeed, failed to do so in the third patientwhose symptoms became more troublesome whilsthe was treated with Warfarin for attacks of monocu-lar blindness. Since the attacks are due to an abnor-mality in bloodflow they can only be abolished bysurgery which improves the cerebral circulation. It istherefore no accident that the largest number ofpatients with this condition reported in the literatureis to be found in a series of papers from the MayoClinic describing surgical ways of improving cerebralbloodflow.9-'3 Almost a third of the 74 patientsoperated on had what the authors termed "primaryorthostatic cerebral ischaemia" ,'° 1 1 (the remainderhad orthodox transient ischaemic attacks). Fromtheir brief description it is clear this is the conditionwe are describing. The Mayo Clinic patients had "amajor postural fall in their retinal artery pressureswithout a proportionate fall in peripheral bloodpressure, and frequent episodes of fainting ordeficits of cerebration or memory".9 These patients



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890also had occlusions of their major extra-cranial vas-culature which is why the authors were forced toresort to the technically demanding procedures ofsuperficial temporal-middle cerebral or occipital-posterior inferior cerebellar arterial anastamoses.The clinical details of these patients are not suppliedand the authors seem to imply that a conditionwhich provided almost one in three of their seriesmust be well recognised. That belief is mistaken. Wecould find few references to what we suspect may bea fairly common manifestation of cerebrovasculardisease. (We encountered four examples in 18months.) None of the published accounts adequatelydescribe the condition.Ford and his colleagues reported on their experi-

ences of carotid endarterectomies on patients withdizziness, drop attacks and confusion."4 A memberof his audience described a patient with severe bilat-eral carotid stenoses "who was bedridden; if heraised his head from the pillow he got dizzy and if hestood up he fainted".'5 Caplan and Sergays fullydescribed four patients of particular interest.'6 Allhad severe occlusive cerebrovascular disease andeach one developed posturally related symptomswithout a marked fall in his systemic blood pressure.They observed these phenomena whilst theirpatients were in hospital recovering from a cerebralinfarct. But there were two interesting differencesbetween their patients and ours and these wouldsuggest that the syndrome of "primary orthostaticcerebral ischaemia" may be more variable than wehave described. First, Caplan and Sergays reportedclear focal symptoms whereas our patients experi-enced rather vague and generalised ones. In twoinstances their complaints could be attributed to lefthemisphere dysfunction and in the remaining two, tobrain stem disturbance. Second, these posturallyrelated symptoms subsided spontaneously in a weekor two whereas our patients seemed to becomeincreasingly disabled by their attacks.We note that three of our four patients had diab-

etes mellitus. We do not, however, believe thatdiabetic autonomic neuropathy played a significantrole in the patient's symptoms. Two of the diabeticpatients did not experience any fall in their systemicblood pressures on standing. The blood pressure diddrop in the third patient but this drop persisted afteroperation even though the symptoms were relieved.Evidently, the attacks were not dependent on pos-turally related falls in systemic blood pressure result-ing from impaired autonomic control. Could theattacks have been due to an effect on the autonomicregulation of cerebral blood flow? We believe notthough we lack the data to prove this assertion. Thefall in retinal artery pressures we recorded, on stand-ing, were so great that, it seemed to us, unnecessary

Stark, Wodak

to postulate an additional, autonomically inducedfailure or arteriolar dilation to account for the pre-sumed drop in cerebral perfusion. The occurrence ofsimilar symptoms in Takayasu's disease'7 18 furthersupports our view for autonomic neuropathy is not afeature of this condition.

Patients with Takayasu's disease developed wide-spread arterial narrowings and occlusions. Theangiographic abnormalities may be extensive as inthe patients we have described, though the arteriallesions are due to an arteritis rather than athero-sclerosis. In two series the majority of patientsexperienced posturally related dizziness or syn-cope.'7 18 One patient had a major seizure wheneverhis head was elevated, presumably as a result ofcerebral ischaemia.

Ross Russell has attributed the sensitivity to pos-tural changes seen in patients with severe and wide-spread arterial narrowings to an exhaustion of thecompensatory reserves of the cerebral circulation.'9Normally when one major extracranial vessel isoccluded, the Circle of Willis and the other extra-cranial vessels will help maintain the cerebral circu-lation. But if these arteries are also diseased thencerebral blood flow can only be maintained by thedilatation of intracerebral resistance vessels. It isthese vessels which normally dilate to compensatefor a fall in cerebral perfusion pressure. Once theyare maximally dilated the brain can no longer makefurther adjustments for any reduction in arterialpressure. It will become exquisitely sensitive toseemingly minor changes in cerebral arterial pres-sure. On standing, the pressure in the carotidarteries will inevitably be diminished by the 15 to 20cm column of blood from the heart to the neck. Inthe presence of widespread cerebrovascular diseasepatients may actually require a rise in their brachialblood pressures on standing in order to maintainadequate cerebral perfusion and could well proveintolerant of even the mild postural hypotensiveeffects of drugs such as antidepressants and tranquil-lisers.The remedy for such an unhappy situation is

surgery, and its effectiveness is readily apparent.Carotid surgery in conventional transient ischaemicattacks is often performed in the hope of preventinga cerebral infarct which such transient ischaemicattacks may portend. Patients with orthostatic cere-bral symptoms and severe cerebrovascular diseasemay also face a considerable risk of cerebral infarc-tion but their immediate problem is the symptomsthey develop whenever they try to get up from theirbed. These symptoms can be abolished by vascularsurgery. We were able to offer our patients surgeryto their carotid arteries but in the presence of wide-spread arterial occlusions this may not always be



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feasible. Indeed the Mayo Clinic patients alreadyreferred to required an anastomosis between theirextra-cranial and intra-cranial arteries. The resultsof this more demanding procedure were equallygratifying: 17 of the 21 patients with "primaryorthostatic cerebral ischaemia" were improved bysurgery.' "1

Surgery however is not without its hazards. Wehave described the turbulent post-operative courseof our third patient, a course remarkably similar tothe confusion and fluctuating focal signs one of theMayo Clinic patients developed.'0 Beyond statingthat the graft was functioning no explanation wasoffered. In our case the disobliteration of anoccluded carotid was followed by a profound andglobal disturbance of cerebral function which we toofound hard to explain. It would be helpful to followsuch a patient in a centre which had the facilities tomeasure cerebral blood flow. Fortunately bothpatients made a satisfactory recovery and we 'con-tinue to believe that "primary orthostatic cerebralischaemia" is a condition worthy of diagnosis andtreatment.

References

'Wunsh SE. Ophthalmodynanometry. N Engl J Med1969;281:446.

2Toole JF. Ophthalmodynanometry, a simplified method.Arch Int Med 1963;112:981-2.

Adams RD, Victor M. Principals of Neurology. NewYork: McGraw Hill Book Co., 1977;528.

4 Walton JN. Brain's Diseases of The Nervous System. 8thed. Oxford: Oxford University Press, 1977;330.

'Toole JF, Cole M. Ischaemic cerebrovascular disease.In: Baker AB, Baker LH, eds. Clinical Neurology.Hagerstown: Harper & Row, 1981;Chapter 10.

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Fisher CM. Observations of the fundus oculi in transientmonocular blindness. Neurology (Minneap) 1959;2:333-47.

Russell RWR. Observations on the retinal blood vesselsin monocular blindness. Lancet 1961 ;2: 1422-8.

8Kendell RE, Marshall J. Role of hypotension in thegenesis of transient focal cerebral ischaemic attacks.Br Med J 1963;2:344-8.

9Houser OW, Sundt TM, Holman CB, et al. Athero-matous disease of the carotid artery: Correlation ofangiographic, clinical and surgical findings. JNeurosurg 1974;41:321-31.

Sundt TM, Piepgras DG. Occipital to posterior inferiorcerebellar artery bypass surgery. J Neurosurg 1978;48:916-28.

"Sundt TM, Siekert RG, Piepgras DG, et al. Bypasssurgery for vascular disease of the carotid system.Mayo Clin Proc 1976;51:677-92.

2Whisnant JP. Extracranial-intracranial arterial bypass.Neurology (Minneap) 1978;28:209-10.

Sundt TM, Whisnant JP, Piepgras DG, et al. Intracranialbypass graft for vertebrobasilar ischaemia. Afayo ClinProc 1978;53:12-8.

Ford JJ, Baker WH, Ehrenhaft JL. Carotid endarterec-tomy for nonhemispheric transient ischaemic attacks.Arch Surg 1975;110:1314-7.

15Thompson JE. In: Discussion, Ford JJ, Baker WH,Ehrenhaft JL. Carotid endarterectomy for nonhemis-pheric transient ischaemic attacks. Arch Surg1975;110:1316.

16 Caplan LR, Sergay S. Positional cerebral ischaemia. JNeurol Neurosurg Psychiatry 1976;39:385-91.

17 Currier RD, De Jong RN, Bole GG. Pulseless diseases:central nervous system manifestations. Neurology(Minneap) 1954;4:818-30.

"Ross RS, McKusick VA. Aortic arch syndromes. ArchInt Med 1953;92:701-40.

19 Russell RWR. Less common varities of cerebral arterialdisease. In: Russell RWR, ed. Cerebral Arterial Dis-ease. Edinburgh: Churchill Livingstone, 1976;290.



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