Page 1026 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Cardiovascular system 1001

VetBooks.ir 8.29

Fig. 8.29 Aortic root rupture in a 7-year-old
Thoroughbred stallion with a history of sudden
onset of colic signs and a new right-sided continuous
murmur. Right-sided long-axis view, taken from the
right 4th ICS, showing the right heart and aorta in
magnification. Colour-flow Doppler reveals diastolic
flow in red from the aorta into the right ventricle
due to rupture of the aortic root, dissection into the
interventricular septum and creation of an AV fistula.
RV = right ventricle; RA = right atrium; Ao = aorta;
LV = left ventricle.

AORTOILIAC THROMBOSIS the vessels should be evaluated. Thrombi are more
commonly identified in the terminal aorta. The
Definition/overview pulse quality may be reduced. Transrectal ultraso-
Thrombosis of the terminal aorta, the divisions of nography of this area is useful in identifying thrombi
the aorta, or any portion thereof may cause ischaemic (Fig. 8.30). Variable echogenicity within the ves-
myopathy of the supplied muscles of the hindlimbs. sel is suggestive of a thrombus. Colour Doppler
evaluation of blood flow provides a more objective
Aetiology/pathophysiology evaluation.
This event is of uncertain aetiology. In some cases,
an association with Strongylus vulgaris larval migra- Management/prognosis
tion has been made. Stall rest and anti-inflammatory therapy is indi-
cated. Larvicidal anthelmintics are indicated if larval
Clinical presentation migration is suspected. The prognosis is guarded to
Clinical signs are variable. One or both limbs may poor.
be involved. A vague hindlimb lameness that is
potentiated by exercise is common. Limb exami- THROMBOPHLEBITIS
nation may reveal a slightly decreased temperature
in the affected limb, a slight decrease in peripheral Definition/overview
pulse or reduced filling in the saphenous vein. These Thrombus formation following venous catheterisa-
signs may be more pronounced following exercise. tion or injection is a relatively common complica-
Sweating and tachypnoea or colic-like signs may be tion. The jugular vein is most commonly affected,
present. primarily due to its predominant use for venous
access. Often, the thrombus is relatively small and
Differential diagnosis only affects functioning of the catheter. In some
Any cause of hindlimb lameness, colic or exertional cases, the vein becomes completely occluded and
myopathy can produce similar signs. abscessation may develop.

Diagnosis Aetiology/pathophysiology
Palpation p/r is indicated. The aorta and where it While thrombophlebitis may be preceded by
divides should be carefully palpated. Pulsations in poor aseptic technique or irritant medication