Key-words:
Antithrombin III deficiency - carotid cavernous fistula - deep vein thrombosis - sinus
thrombosis
Introduction
Carotid cavernous fistula (CCF) is a fatal abnormal communication between internal
or external carotid artery and cavernous sinus. The lesion is classified as traumatic
or spontaneous (based on etiology), high or low (based on the velocity of flow) and
direct or dural (based on anatomy). CCF is almost always traumatic and 70%–90% are
direct. Here, we discuss a young female who presented with spontaneous direct CCF
with a rare association.
Case Report
A 27-year-old female with no premorbidities or trauma presented with right hemicranial
headache, projectile vomiting, redness, pain, blurring of vision right eye for 21
days. A week ago, she had developed diplopia on looking to the right. She had bilateral
proptosis, chemosis, periorbital edema, and drooping of the right eyelid. Nervous
system examination revealed visual acuity of 6/18 both eyes with the normal visual
field by confrontation, lateral rectus palsy on the right and minimal paresis of the
third, fourth, and sixth cranial nerves on the left. Bilateral orbital bruit was present.
Corneal reflexes were absent bilateral, and sensation in the region of the right ophthalmic
division of trigeminal nerve was decreased.
Her complete blood count, blood sugar, renal, liver thyroid functions, electrolytes,
prothrombin time, and activated partial thromboplastin time were normal. Magnetic
resonance imaging of the brain showed mildly prominent right superior ophthalmic vein
and bilaterally enlarged cavernous sinuses with multiple flow voids adjacent to internal
carotid arteries (ICAs) and flow-related enhancement in time-of-flight magnetic resonance
angiography suggestive of carotid-cavernous fistula (CCF) [[Figure 1]]a. Digital subtraction angiography showed right CCF with multiple rents in laceral
and cavernous segments of right ICA [[Figure 1]]b. A diagnosis of spontaneous CCF was made after ruling out all secondary causes,
including connective tissue diseases. 6F Neuron 070 was navigated over the guide wire
and tip parked in the right proximal petrous ICA. Two Echelon microcatheters were
passed one after the other, and the distal end was parked in horizontal segment of
right cavernous. The cavernous and proximal petrous ICA in right was occluded from
distal to proximal aspect starting from anterior genu with eleven coils (Axium 3D
5 × 10, 4 × 8, 3 × 8, two 2 × 4, 3 × 6, 4 × 10, 6 × 20, GDC 6 × 15, 6 × 20, 7 × 30)
and two coils were deployed through the rent into the cavernous sac followed by injection
of 0.35 ml of Squid18 into the coil mass [[Figure 1]]c. Subsequent check angiogram revealed complete obliteration of fistula and flow
beyond right petrous ICA [[Figure 1]]d. She improved clinically and after 2 weeks only had mild diplopia looking to the
right.
Figure 1: (a) Prominent right superior ophthalmic vein and bilateral enlarged cavernous sinuses
with multiple flow voids adjacent to internal carotid arteries with flow related enhancement
in time-of-flight magnetic resonance angiography. (b) - Digital subtraction angiography
showed right cavernous fistula with multiple rents in laceral and cavernous segments
of right internal carotid artery. (c) - Coil mass inside right cavernous and proximal
petrous internal carotid artery. (d) - complete obliteration of fistula and flow beyond
right petrous internal carotid artery in subsequent check angiogram
She was discharged from hospital 1 week after the procedure. She returned to her normal
daily routine activities. However for mild diplopia while looking to the right, she
was perfectly normal in her first follow-up visit 1 week after discharge. She was
planned for an angiogram after 3 months to assess collateral formation if any and
was sent home. One month after procedure, she presented with pain and swelling left
thigh and was detected to have a deep vein thrombosis (DVT) of the left femoral vein.
In view of young nonsituational DVT a prothrombotic workup was done which revealed
very low antithrombin III (ATIII) level of 21.7% (normal 80%–120%). Homocysteine,
factor V leiden mutation, protein S and protein C activities, antiphospholipid antibodies
were normal. She was started on warfarin after bridging with heparin. She improved
symptomatically and had no further thrombotic episodes for the past 12 months.
Discussion
CCF is commonly produced by trauma, atherosclerosis, systemic hypertension, collagen
vascular diseases, pregnancy, and childbirth. None of the above-mentioned conditions
were present in our patient. A less noticed cause of CCF is cerebral sinus thrombosis.[[1]] Cerebral sinus thrombosis predisposes to CCF in two ways. It may be due to opening
up of spontaneous channels between carotids and sinus due to the increased intracranial
pressure produced by thrombosis in venous channels. The second possibility is thrombosis
producing ischemia leading to neoangiogenesis.[[2]] The absence of sinus thrombosis during presentation does not rule out this possibility
as they are not always simultaneously seen. There are reports of CCF developing even
1 year after sinus thrombosis.[[3]]
Thrombogenic conditions like ATIII deficiency are known to induce spontaneous thrombosis,
including cerebral sinus thrombosis. A study conducted in Germany detected the higher
prevalence of G20210A mutation in patients with CCF.[[4]] A similar study in Japan found 22.2% of the study population with spontaneous CCF
had protein S deficiency.[[5]] However, the study was not statistically significant as the study population was
small and prevalence of protein S deficiency was very high in the Japanese population.
To the best of our knowledge, no case of CCF has been reported previously showing
concurrent ATIII deficiency though similar mechanisms are plausible with all procoagulant
conditions. Dural venous thrombosis was not thought of initially in our patient and
later as the patient was already on warfarin; we did not do a computed tomographic
venogram to look for the same. It is debatable whether to start anticoagulant therapy
in a patient with spontaneous CCF and incidentally detected concurrent ATIII deficiency
without any other thrombotic manifestations. However, a search into probable underlying
causes may be beneficial for better outcomes after surgery. This patient had a DVT
later which lead to her pro-coagulant workup and subsequent starting of warfarin.
Since anticoagulation, she never had any further morbidities.
Conclusion
CCF is a potentially fatal illness. Underlying pro-coagulant conditions and sinus
thrombosis may be checked for, especially in a young spontaneous CCF patient as anticoagulant
therapy following corrective procedure may significantly improve long-term outcome
and reduces recurrences.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms.
In the form the patient(s) has/have given his/her/their consent for his/her/their
images and other clinical information to be reported in the journal. The patients
understand that their names and initials will not be published and due efforts will
be made to conceal their identity, but anonymity cannot be guaranteed.
