Focal Motor Seizures Complicating
Carotid Endarterectomy
LTC Jerry R. Youkey, MC, USA; G. Patrick Clagett, MD; CPT Jonathan H. Jaffin, MC, USA;
MAJ Joseph E. Parisi, MC, USA; Norman M. Rich, MD
\s=b\ We studied four
patients with focal motor seizures complicating carotid endarterectomy and compared them with 14
other cases reported previously. Seventeen of the 18 patients
had high-grade carotid stenoses. A severe unilateral headache
usually preceded seizure activity, which was followed by
prolonged Todd's paralysis. Eight patients had histories of
ipsilateral stroke. There was no association with perioperative
hypertension. Two patients who were receiving heparin sodium had intracerebral hemorrhages that caused one of the
two postoperative deaths. The patency of all endarterectomized carotid arteries was recorded by arteriography or
noninvasive studies. These data suggest that patients who
have severe unilateral headaches following ipsilateral carotid
endarterectomy for high-grade stenoses are at risk for focal
motor seizures. The roles of antithrombotic agents and anti\x=req-\
seizure medication in this setting are unclear.
(Arch Surg 1984;119:1080-1084)

the incidence of carotid endar¬
in the United States has increased from
7.4/100,000 to greater than 24/ , .1 Despite many large
series detailing major and minor complications,25 we know
of only two reports of focal motor seizures complicating
carotid endarterectomy.6,7 In 1975, Sundt et al8 described
five patients who had focal motor seizures postoperatively
among 342 patients who had undergone carotid endarterec¬
tomy; they suggested that the disorder was a result of
postoperative cerebral hyperperfusion. Wilkinson et al,7 in

past decade,
During
terectomy
the

Accepted for publication Jan 19, 1984.
From the Department of Surgery, Walter Reed Army Medical Center,
Washington, DC (Drs Youkey, Clagett, and Jaffin); the Department of
Neuropathology, Armed Forces Institute of Pathology, Washington, DC (Dr
Parisi); and the Department of Surgery, Uniformed Services University of
the Health Sciences, Bethesda, Md (Drs Youkey, Clagett, and Rich).
The views or assertions contained herein are the private views of the
authors and are not to be construed as reflecting the views of the
Department of the Army or the Department of Defense.
Reprint requests to Peripheral Vascular Surgery Service, Walter Reed
Army Medical Center, Washington, DC 20307 (Dr Youkey).

1980, reported three cases from the University of Iowa
College of Medicine, Iowa City, and speculated that cere¬
bral embolization was the cause. In 1981, Sundt et al6

reported 11 cases of transient focal seizures following
carotid endarterectomy among 1,145 procedures performed

between 1972 and 1981.
Previous reports of experience with carotid endarterec¬
tomy at the Walter Reed Army Medical Center, Washing¬
ton, DC,9"11 did not include the problem of perioperative
seizure disorders. In retrospect, there was one case in 1967.
Between 1966 and 1982, four cases of severe motor seizure
complicated the postoperative course of approximately
1,100 patients having carotid endarterectomies: two of these
occurred in 1982. These cases are presented in detail and
compared with those reported by Sundt et al and Wilkinson
et al in an attempt to identify risk factors for development of
this complication.6^
REPORT OF CASES
Case 1.—A 60-year-old woman with type IV hyperlipidemia had
episode of left amaurosis fugax, slurred speech, right-sided
facial numbness, and weakness of the right hand and foot that was
associated with paresthesias. She had bilateral carotid bruits and
normal results of a neurologic examination. Ophthalmodynamometry showed markedly diminished ocular pressure in the left eye
(right eye, 90/20 mm Hg; left eye, 50/10 mm Hg). Arteriography
(Fig 1, top left) showed bilateral high-grade internal carotid artery
stenoses, with the right side appearing to be the most critical. The
intracranial circulation was normal. A right carotid endarterec¬
tomy without a shunt was performed with the patient under
cervical block anesthesia. The postoperative period was unre¬
markable.
Five weeks later, the patient returned for a left carotid endar¬
terectomy and reported that in the interim she had had a single
transient ischemie attack on the left side of her brain. A left carotid
endarterectomy without a shunt was performed with the patient
under cervical block anesthesia. The operating surgeon noted a
an

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Fig 1.—Preoperative selective carotid arteriograms of patients with ipsilateral focal motor seizures
following carotid endarterectomy. All reveal high-grade internal carotid artery stenoses. Top left, Case
1. Top right, External carotid artery is occluded in case 2. Bottom left, Arrows indicate distal internal
carotid artery string sign in case 3. Bottom right, Case 4.

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postoperative course was unremarkable except for a persistent,
moderately severe left-sided parietal headache. The OPG became
normal on the left and remained abnormal on the right. Because of
the headache and the right-sided lesion, he remained in the
hospital. A regimen of aspirin and dipyridamole, which had been
started prior to operation was continued. The patient's BP was well
controlled throughout the hospitalization.
On the 11th postoperative day, the patient suffered a generalized
tonic-clonic seizure on the right side that was characterized by
incontinence and jacksonian march that began in the right hand (it
required 1 g intravenous [IV] phenytoin sodium for control).
Postictally, he was found to have impaired recent memory, inability
to follow commands, echolalia, dysmetria, and confabulation, all of
which completely resolved during 48 hours. An EEG, nuclear
medicine brain scan, and contrast-enhanced computed tomo¬
graphic (CT) scan of the brain were normal. No metabolic abnor¬
malities were found. A dosage of 300 mg/day of phenytoin sodium
was maintained.

Fig 2.—Low-power photomicrograph of right parietal cerebral cor¬
tex in case 4. Arrows indicate small perivascular hemorrhage;
arrowheads, multiple adjacent hemorrhages (hematoxylin-eosin,

x48).

patent but pulseless left internal carotid artery during his dissec¬

tion and an excellent pulse on completion of the procedure. The
operation was uncomplicated and good internal carotid artery
back-bleeding was present. On the afternoon following the opera¬
tion, the patient complained of a severe left-sided frontal head¬
ache. In the ensuing days, the headache persisted and increased in
intensity. Her BP and results of a neurologic examination remained
normal.
On her sixth postoperative day, the patient had a grand mal
seizure with right upper and lower extremity and facial tonic-clonic
movements, during which she aspirated gastric contents and
sustained cardiopulmonary arrest. She was successfully resusci¬
tated. One hour later, another seizure developed, despite treat¬
ment with phenytoin sodium and phénobarbital sodium, followed
by Todd's paralysis manifested by right hemiparesis that lasted six
hours. The patient had no more seizures and her headache gradu¬
ally abated. A subsequent EEG, and nuclear medicine brain scan,
and results of ophthalmodynamometry were normal. At the time of
the seizure, there were no metabolic causes identified. The patient
was treated with phenytoin and phénobarbital for one year.
Six years later, the patient had right amaurosis fugax and
underwent repeated carotid endarterectomy with Dacron patch
angioplasty for recurrent carotid stenosis. Preoperative arteriog¬
raphy confirmed a widely patent normal left carotid system. Her
course was uncomplicated, and, at the time of writing, she contin¬
ued to do well.
Case 2.—A 58-year-old man with hypertension and a previously
silent, inferior wall myocardial infarction had episodic near-syn¬
cope and right upper extremity weakness and paresthesias. An
examination showed bilateral carotid bruits, and ocular pneumoplethysmograms (OPGs) were abnormal bilaterally. Ar¬
teriography (Fig 1, top right) confirmed severe bilateral internal
carotid artery stenoses that were worse on the left. The in¬
tracranial circulation was normal. The patient underwent uncom¬
plicated left carotid endarterectomy with a shunt. The initial

A repeated arteriogram disclosed a widely patent and normal
left carotid system and an unchanged, high-grade right internal
carotid artery stenosis. There was no artériographie evidence of
intracranial thromboembolization. The patient underwent an un¬
eventful right carotid endarterectomy. Two years later, he contin¬
ued to take phenytoin and remained asymptomatic for cere¬
brovascular disease.
Case 3.—A 60-year-old woman with diabetes mellitus, two
previous myocardial infarctions, and stable angina pectoris experi¬
enced three left hemispheric transient ischemie attacks, followed
by a stroke. Her expressive aphasia resolved within 72 hours, but
mild right hemiparesis persisted. She had bilateral soft carotid
bruits and an abnormal OPG on the left. A CT scan of the brain
confirmed a left-sided frontal infarct, and administration of
1,300 mg/day of aspirin was begun. Arteriography (Fig 1, bottom
left) demonstrated a marked left carotid stenosis with a distal
internal carotid artery string sign; the right carotid had a smooth,
30% narrowing. The left cerebral hemisphere was perfused via the
right internal carotid artery—the intracranial vessels were nor¬
mal.
Five weeks after her cerebral infarct, the patient underwent an
uncomplicated left carotid endarterectomy. A shunt was used and
there was no thrombus present. The distal internal carotid artery
was widely patent with good back-bleeding. Postoperatively, she
complained of a left-sided headache and the results of a neurologic
examination were unchanged. The administration of aspirin was
continued in the postoperative period. The headache increased in
severity during the next two days. On the third postoperative day,
the patient suffered a grand mal seizure with clonic activity on the
right side of the body that lasted 90 minutes. Control required IV
administration of 900 mg of phenytoin sodium, 300 mg of phénobar¬
bital sodium, and 25 mg of diazepam. Postictally, she had flaccid
paralysis of the right side of her body for 12 hours. At the time of
seizure, no metabolic abnormalities were found. A subsequent
nuclear medicine brain scan, a contrast-enhanced CT scan of the
brain, and OPG were normal. At discharge, the patient had no
complaints of headache, and results of a neurologic examination
were normal. Administration of phenytoin and phénobarbital was
continued.
Case 4.—A 61-year-old woman with controlled hypertension
sustained a right hemispheric stroke without antecedent symp¬
toms. Three months later, she was referred for evaluation of her
symptoms and was found to have a right carotid bruit and an
abnormal OPG on the right. Arteriography (Fig 1, bottom right)
confirmed a high-grade right internal carotid artery stenosis and
minimal narrowing of the left internal carotid artery. There was
minimal nonstenotic atherosclerotic disease in the intracranial

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Data Summary of Patients Having Seizures After Endarterectomy*

Study
Sundt
et al,6 1981

Wilkinson et al,7
1980

Present Study

Total

Patients

11

18

High-grade carotid stenosis
History of ipsilateral stroke
Preoperatively controlled hypertension
Postoperative hypertension
Type of preoperative antithrombotic agent
Intraoperative shunt used
Severe postoperative unilateral headache
Todd's paralysis
Postoperative intracerebral hemorrhage
Postoperative patency, method of proof
Postoperative day of first seizure

11

17

5t

Aspirin, 2; heparin, 2

Aspirin, 1; dipyridamole, 1

Aspirin, 3

5t

11

Often

All

11

2t
Angiogram, 11
5-7

Normal brain scan after seizure

5t

Died

1

Often
17

1

Angiogram, 1; Doppler study, 2

Angiogram, 2; OPG, 2§

18

4-6

3-11

3-11
10

1

*Number of patients is given for each category, except for severe postoperative unilateral headache, for which exact information was not available; and
postoperative day of first seizure, for which a range of d»y is given,
tlnformation was unavailable for last six patients of Sundt et al.6
^Reportedly, these were the only two patients taking heparin postoperatively; one of them died.
§OPG indicates ocular pneumoplethysmogram.

vessels. The patient underwent an uncomplicated right carotid
endarterectomy with a shunt under general endotracheal anesthe¬
sia. A postoperative OPG was normal. The BP was well controlled
throughout the hospitalization and a regimen of 1,300 mg/day of
aspirin was maintained. The development of a severe right-sided
frontal headache prompted an eight-day postoperative hospitaliza¬
tion during which the results of a neurologic examination remained
normal.
Three days after discharge, the patient's condition was evaluated
for increased severity of the right-sided frontal headache. Her BP
and neurologic and funduscopic examination results were normal.
That evening her headache became excruciating. The patient
vomited several times and became semiconscious following clonic
activity of the left side of the body. When seen at her local hospital,
she was in a postictal state with flaccidity of her left side. An
emergency CT scan of the brain demonstrated a deep right
hemispheric hemorrhage. The patient's condition deteriorated,
and she died the following morning.
At the postmortem examination, the right cerebral cortex

displayed multiple recent pericapillary microhemorrhages (Fig 2)

and a massive (diameter, 4 cm) area of recent hemorrhage in the
deep white matter of the posterior right frontal lobe. There was
herniation of the right uncus as a result of unilateral cerebral
edema and hemorrhage. In the watershed distribution of supply
between the right anterior and middle cerebral arteries, there
were mutliple small areas of organizing pseudolaminar infarction,
especially in the depths of the sulci. There were no intravascular
thromboemboli. Many small vessels were hyalinized.

COMMENT
The clinical features of these four cases and the 14

previously reported cases of focal motor seizures following
carotid endarterectomy are detailed in Table 1. It appears
that the patient who has a severe unilateral headache in the
perioperative period following ipsilateral carotid endar¬
terectomy for a high-grade stenosis is at risk for focal motor
seizures, followed by major transient postictal neurologic

deficits. The seizures occur between three and 11 days
following operation, but most manifest themselves, by the
seventh postoperative day. Although half of the patients
had a preoperative history of ipsilateral stroke, as Wilkin¬
son et al7 observed, this is not a prerequisite for the
disorder. Postoperative hypertension is not an associated
problem. The roles of preoperative hypertension, antithrombotic agents, and intraluminal shunts are unclear
because of incomplete information.
The pathophysiology of this disorder is unknown. An
association of carotid occlusive disease and cerebral embo¬
lism with seizures has been reported,12 but this is uncom¬
mon. Although Wilkinson et al7 have suggested that focal
motor seizures following carotid endarterectomy are the
result of cerebral embolization, the few of these patients
who received postoperative arteriography had normal in¬
tracranial vasculature without evidence of thromboem¬
bolism. The largely circumstantial evidence, so far, lends
more support to the thesis of Sundt et al that this
postoperative seizure disorder is a manifestation of a re¬
gional hyperperfusion syndrome.6,8 The headache that was
experienced by these patients is a distinctly unusual early
symptom of cerebral emboli,13 and is characteristic of the
symptom that Levitón et al ascribed to a transient distur¬
bance in cerebral autoregulation.14 The demonstration by
Sundt et al6 of an increase in regional cerebral blood flow of
more than 100% in their 11 patients corroborates the relative
hyperperfusion. This is also supported by the postmortem
findings in one of our patients (case 4), in which multiple
pericapillary microhemorrhages were found within the
cerebral cortex of the operated hemisphere. This pattern of
damage is similar to changes seen with acute severe hyper¬
tension.15 It would be explainable in this normotensive
patient by a lack of cerebral BP autoregulation with conse-

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quent hyperperfusion of passive fragile end vessels.

The question of cause may be important in the care of
these patients. In the early experience of Sundt et al, the
only two of their patients who received heparin postopera¬
tively suffered major intraparenchymal hemorrhage.6
There is increasing evidence that antithrombotic agents can
play a role in reducing thromboembolic complications in
patients with vascular disease. This has led to the common
use of aspirin in the perioperative period for patients
undergoing carotid endarterectomy. If seizures following
carotid endarterectomy are related to a hyperperfusion
syndrome with the potential for intraparenchymal bleed¬
ing, then perhaps administration of antiplatelet agents
should be discontinued preoperatively in those patients at
highest risk. This would include patients with very tight
stenoses and a history of ipsilateral stroke. The patient who
has a severe headache ipsilateral to endarterectomy of a
tight carotid stenosis should be observed for seven to ten

days, with precautions against seizure being taken. Anti¬
coagulant therapy should probably be avoided. It is our
current practice to institute phenytoin therapy with the
onset of this headache.
Focal motor seizures have complicated 1% of the carotid
endarterectomies performed at the Mayo Clinic, Rochester,
Minn,6 0.4% of those performed at Walter Reed Army
Medical Center. Even though the incidence is low, it is
surprising that seizures have not been reported more
frequently in view of the large number of carotid endar¬
terectomies currently being performed. It is hoped that this
review will stimulate others to report their similar experi¬
ences. In this way, enough cases may be accumulated to
make firmer statements regarding the pathophysiology and
treatment of this interesting and frightening disorder.
Stan Harris, MD, of the Department of Pathology, Pitt Memorial Medical
Center, Greenville, NC, provided the postmortem examination report and

histologie slides of case 4.
References

1. Mohr JP: Asymptomatic carotid artery disease. Stroke 1982;13:
431-433.
2. Beven EG: Carotid endarterectomy. Surg Clin North Am 1975;55:
1111-1123.
3. Thompson JE, Patman RD, Talkington CM: Carotid surgery for
cerebrovascular insufficiency. Curr Probi Surg 1978;15:1-68.
4. Thompson JE, Talkington CM: Carotid surgery for cerebral ischemia.
Surg Clin North Am 1979;59:539-553.
5. Carmichael JD: Carotid surgery in the community hospital: 467
consecutive operations. Arch Surg 1980;115:937-942.
6. Sundt TM, Sharbourgh FW, Piepgras DG, et al: Correlation of
cerebral blood flow and electroencephalographic changes during carotid
endarterectomy with results of surgery and hemodynamics of cerebral
ischemia. Mayo Clin Proc 1981;56:533-543.
7. Wilkinson JT, Adams HP, Wright CB: Convulsions after carotid
endarterectomy. JAMA 1980;244:1827-1828.
8. Sundt TM, Sandok BA, Whisnant JP: Carotid endarterectomy: Complications and preoperative assessment of risk. Mayo Clin Proc 1975;50:

301-306.
9. Rich NM, Hobson RW: Carotid endarterectomy under regional anesthesia. Am Surg 1975;41:253-259.
10. Collins GJ, Rich NM, Andersen CA, et al: Stroke associated with
carotid endarterectomy. Am J Surg 1978;135:221-225.
11. Andersen CA, Rich NM, Collins GJ, et al: Carotid endarterectomy:
Regional v general anesthesia. Am Surg 1980;46:323-327.
12. Cocito L, Favale E, Reni L: Epileptic seizures in cerebral arterial
occlusive disease. Stroke 1982;13:189-195.
13. Adams RD: Recurrent convulsions, in Wintrobe MM, Thorn GW,
Adams RD, et al (eds): Harrison's Principles of Internal Medicine. New
York, McGraw-Hill Book Co, 1970, pp 163-172.
14. Leviton A, Caplan L, Salzman E: Severe headache after carotid
endarterectomy. Headache 1975;15:207-209.
15. Adams RD, Sidman RL: Cerebrovascular diseases, in Adams RD and
Sidman RL (eds): Introduction to Neuropathology. New York, McGraw-Hill
Book Co, 1968, pp 171-183.

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