 |
 |
 |
 |
 |
 |
 |
|
|
|||||||
| Discussion |
A 24-year-old woman was referred for ultrasound examination for a swelling
in the neck. The patient was a known case of chronic renal failure due to
obstructive uropathy and needed hemodialysis. A right-sided carotid-jugular
line insertion had been tried unsuccessfully with a large resultant haematoma
on the right side of the neck. The patient had dysphagia, dyspnea and cough
due to pressure from the neck haematoma. A palpable thrill was felt over
the expansile, pulsatile swelling. On auscultation a bruit was heard. A
clinical diagnosis of a carotico-jugular fistula was made.
RADIOLOGICAL Examination:
The color Doppler revealed a haematoma around the neck vessels A hypoechoic
lesion was seen on right side of neck. This was suggestive of a haematoma
(Figs 1, 2) . There was very high velocity flow in the right internal jugular
vein. There was aliasing due to turbulence and velocities approximately
of 300cms/sec. There was a tortuous fistula at the level of carotid bulb
opening into IJV.
 |
 |
|
Fig.
1
|
Fig.
2
|
 |
 |
|
Fig.
3
|
Fig.
4
|
A DSA with gadolinium contrast revealed a moderate flow fistula between the right common carotid artery and the right IJV with an irregular fistulous tract. Antegrade flow in right ECA and ICA was normal (Fig 6).
 |
 |
|
Fig.
5
|
Fig.
6
|
 |
 |
|
Fig.
7
|
Fig.
8
|
 |
|
Fig.
9
|
DISCUSSION:
Carotid artery-internal
jugular vein arteriovenous fistule are rare. Due to the complex vascular
anatomy in the neck, the diagnosis of arteriovenous fistula should be suspected
in cases of vascular injury caused by penetrating neck trauma. An arteriovenous
fistula is an abnormal communication between the arterial and venous systems.
Arteriovenous fistula between the common carotid artery and internal jugular
vein can be congenital or acquired. The majority of acquired arteriovenous
fistule in the neck are caused by penetrating trauma from gunshot or stab
wounds or iatrogenic injury (as in this case).
The classical clinical findings of vascular injury of arteriovenous fistula
include an audible bruit, palpable thrill, expanding haematoma, loss of
pulse, neurological deficit or arterial bleeding. However, in some cases
these clinical signs may be absent.
Diagnostic modalities
include duplex ultrasonography, colour duplex ultrasonography, standard
angiography, and CT or MRI angiography. Duplex Ultrasonography has an overall
sensitivity of 91-100% and a specificity of 85-98% in evaluating possible
cervical vascular injuries. Colour flow Doppler imaging also has a high
sensitivity and specificity of 91% and 98% respectively. When combined with
careful physical examination, ultrasound provides a relatively safe and
fast diagnostic tool in penetrating neck trauma. Although Doppler ultrasound
analysis carries less risk, angiography is the gold standard diagnostic
tool. In this case, after identifying the arteriovenous fistula with duplex
ultrasonography, we performed carotid angiography to identify and confirm
the site and extent of the high-flow fistula and for assessment for endovascular
intervention. Once the arteriovenous fistula is identified, prompt intervention
is indicated due to the propensity of such fistulas to enlarge, bleed and
cause complications of high-output heart failure. Endovascular embolisation
using a balloon or coil is treatment of choice. Our patient was treated
with balloon embolisation.
A covered stent graft is a viable but costly option. Surgical repair involves
ligation or excision of the fistula. If a large vascular defect remains
following excision, a graft may have to be used.