Headache Medicine, v.5, n.1, p. 25-27, Jan./Feb./Mar. 2014 25

Left internal carotid artery agenesis in a patient

with headache

Agenesia da artéria carótida interna em um paciente com cefaleia

CASE REPORTCASE REPORT

CASE REPORT

ABSTRACTABSTRACT

ABSTRACT

Sometimes in clinical neurology, we diagnose a very rare case.

We report on a patient who presented with crisis of headache

and vomiting (clinically diagnose as migraine). Computed

tomography (CT) scan of the head did not reveal any structural

lesion. Magnetic resonance angiography showed absence of

left internal carotid artery associated with absence of the left

middle cerebral artery (MCA).

KeywordsKeywords

Keywords: Carotid artery; Agenesis; Middle cerebral artery;

Magnetic resonance angiography; Headache

RESUMORESUMO

RESUMO

Às vezes em neurologia clínica, nós diagnosticamos um caso

muito raro. Nós relatamos o caso de um paciente que

apresentava crises de dor de cabeça e vômitos (diagnóstico

clínico de enxaqueca). Tomografia computadorizada da

cabeça não revelou qualquer alteração estrutural. Angiografia

por ressonância magnética mostrou ausência de artéria

carótida interna esquerda associada à ausência de artéria

cerebral média esquerda.

alavrasalavras

alavras

chaves: chaves:

chaves: Artéria carótida; agenesia; artéria

cerebral média, Angiografia por ressonância magnética;

cefaleia

Leão IAT, Rezende CH, Gomes JBL, Almeida RF

Headache Ambulatory, Military Hospital in Belo Horizonte, Military Police of Minas Gerais, Brazil

Leão IAT, Rezende CH, Gomes JBL, Almeida RF. Left Internal Carotid Artery Agenesis in a patient with headache.

Headache Medicine. 2014;5(1):25-27

In 1954, Tode et al.

(3)

described the first case of this

condition and, in 1954, Verbiest et al.

(4)

demonstrated the

absence of the ICA by angiography for the first time.

The most common source of collateral circulation in

the case of the ICA agenesis is via the circle of Willis.

(5)

these cases, the basilar artery or the contralateral ICA

supplies the middle cerebral artery (MCA) and anterior

cerebral artery (ACA) on the side of the absent ICA.

(5)

The cause of the carotid agenesis is not known, but

may be secondary to an insult to the developing embryo.

(5)

The left internal carotid artery is reported to be

affected by dysgenesis three times more often than the

right one.

(6)

We herein report a case of left ICA agenesis presenting

with a history of chronic headaches for the preceding 14

years.

CASE REPORT

A 33-year-old woman, presented to our Headache

Ambulatory with a history of chronic headache since

1999. She described pulsatile, right headache,of

moderate to strong intensity, worsened by physical

activities, associated to nausea, vomiting, photophobia,

phonophobia and osmophobia, 1 to 2 crises (episodes)

per month. She had family history of migraine and took

oral contraceptives.

She came to the emergency room many times because

of crisis of acute headache, refractory (resistant) to usual

pain killers. In the late months the pain became daily,

INTRODUCTION

Agenesis of internal carotid artery (ICA) is a rare

congenital anomalywith an incidence of 0.01%.

(1,2)

Most

of the patients are asymptomatic and is usually discovered

incidentally by computed tomography (CT) or magnetic

resonance imaging (MRI).

26 Headache Medicine, v.5, n.1, p. 25-27, Jan./Feb./Mar. 2014

LEÃO IAT, REZENDE CH, GOMES JBL, ALMEIDA RF

Figure 1. Magnetic resonance imaging.

Figure 2. Angio-MR.

soften, bilateral and pressing. She related abuse of pain

killers.

A psychiatric treatment was indicated because she

had anxiety and insomnia. Also, she was going through

dental control due to myofascial pain. She is using

stabilizing splint and does physiotherapy for temporo-

mandibular joint dysfunction.

Her pain was refractory to various pain-killers and

non-steroidal anti-inflammatory drugs, such as naproxen;

cefalium®; naratriptan; sumatriptan; ibuprofen and

ergotamine.

She used many preventive medicines against

migraine, with partial results, e.g. fluoxetina; bupropion;

venlafaxine; alprazolam; clonazepan; atenolol and

cyclobenzaprine.

In the beginning, she made CT scan (computerized

tomography), which was normal.

Angio RM (magnetic resonance angiograph) of the

brain and of the carotid and vertebral arteries in

3.September.2013 showed left ICA agenesis (Figures 1

and 2).

Nowadays she is taking mirtazapine (30mg/day),

sumatriptain and ketorolac with good response.

DISCUSSION

Embryologic considerationsEmbryologic considerations

Embryologic considerations

Alterations of the embryologic development of the

cerebral arterial circulation may lead to agenesis or

hypoplasia of the carotid arteries.

According to Streeter,

(7)

] Padget

(8)

and McLone and

Naidich,

(9)

two branches of the primitive ICA develop early

in the embryogenesis, originating from the third aortic arch.

In its primitive form, the internal carotid reaches the cephalic

region up to the level of the Rathke`s pouch where two

primary divisions occur. One cranial branch extends

anteriorly to supply the developing forebrain via the

anterior choroidal, middle cerebral, anterior cerebral and

primitive olfactory arteries.

A second posterior branch gives rise to the posterior

choroidal, diencephalic and mesencephalic arteries. As

these branches advance caudally, anastomoses are made

Headache Medicine, v.5, n.1, p. 25-27, Jan./Feb./Mar. 2014 27

Correspondência

Inês Alice TInês Alice T

Inês Alice T

eixeira Leixeira L

eixeira L

eãoeão

eão

Rua da Bahia, 2311/901 – Lourdes

30160 012 – Belo Horizonte, MG Brazil

email: inestleao@hotmail.com

with the developing longitudinal neural arteries supplied

by the trigeminal artery connections to the primitive ICA.

Agenesis or aplasia of ICA results from abnormal

regression of the first and third aortic arch

(10,11)

Lie

(5)

referred to agenesis as a complete absence of

the entire ICA and carotid canal.

Clinical and radiological considerationClinical and radiological consideration

Clinical and radiological consideration

ICA agenesis is a rare congenital anomaly, with an

estimated incidence of 0.01%, with more frequent

symptom encountered in adults rather than in children or

adolescent patients.

(1,2)

Relatively a small number of

symptomatic cases of absence of the ICA have been

reported in children, suggesting that initially the collateral

pathways are sufficient to support cerebral perfusion

(5)

This condition is known to occur more frequently in left

sided ICA`s. The ratio between right and left ICA is 1:3

(12)

Patients with agenesis of the ICA are often

asymptomatic because of the collateral pathways.

However, patients may present with headaches, seizures

or neurological deficits secondary to cerebral ischemia,

or intracranial hemorrhage

(13)

. Our patient had recurrent

headache increases clinically diagnosed as migraine.

Diagnosis of ICA agenesis entails documenting the

absence of the ICA by conventional angiography, MRA

or MSCT angiography, and the absence of the carotid

canal by CT. Collateral flow is most commonly supplied

through the circle of Willis, but may be also provided by

embryonic vessels or the external carotid artery. MRA

appears to be an effective and sensitive method for

detecting absence of the ICA. ICA agenesis is usually

encountered during the diagnosis process.

Our patient has no complaints at present and is being

followed up with periodic physical and neurological

examination. We believe that these findings in our patient

are instructive and will help to further our understanding

of the embryologic development of the carotid arteries.

CONCLUSIONS

ICA agenesis is a rare vascular anomaly and is a

typically discovered incidentally as patient are often

asymptomatic. In our case, this patient has presented in

our ambulatory with complaint of crisis of refractory

headache, diagnosed as migraine.

This rare anomaly must be distinguished from ICA

stenosis or occlusion.The collateral circulation should also

be documented by conventional angiography, particularly

prior to carotid endarterectomy, transphenoidal

hypophyseal surgery or inducing hypotension. Collateral

flow is most commonly supplied through the circle of Willis,

but may be also provided by embryonic vessels or the

external carotid artery.

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LEFT INTERNAL CAROTID ARTERY AGENESIS IN A PATIENT WITH HEADACHE