Page 300 - Feline Cardiology

308 Section H: Arterial Thromboembolism

Figure 20.2. A cat presenting with the typical caudal paresis Figure 20.4. Footpads from a cat presenting with ATE. Note the
following ATE of the terminal aorta. Photograph courtesy of Dr. foot that is not affected has normal, pink color (above) and the
John Bonagura. affected foot pads are cyanotic (below).
Arterial Thromboembolism and paresis. When the terminal aorta is involved, femoral

arterial pulses are typically poorly palpable (distal/
partial embolus) or not palpable (absence of femoral
arterial circulation) and the distal limbs are cold.
The cranial tibial and gastrocnemius muscles become
firm within 10 to 12 hours postembolization due to
ischemic myopathy, and remain painful on palpation.
Usually they become softer 24 to 72 hours later; however,
in some cats the degree of firmness will increase over the
first few days, suggesting poorer perfusion. The nail beds
and pads may appear pale to cyanotic depending on the
severity and duration of ischemia (Figure 20.4); often
there is progression from pallor to cyanosis over the first
12 hours of embolization. Neurologic examination typi-
cally reveals a sciatic neuropathy with absent deep pain
and withdrawal, but usually normal patellar reflexes.
Rectal tone is typically maintained, and urinary bladder
function is usually maintained. Less common emboliza-
tion sites include the renal, mesenteric, pulmonary,
Figure 20.3. A cat with nonweightbearing, knuckling of the dis- coronary, and cerebral arteries. Occlusion of these vessels
tal limb due to ATE affecting the left forelimb. Photograph cour- may lead to azotemia, bloody diarrhea, or sudden death
tesy of Dr. John Bonagura. and other abnormalities, such as renal infarctions on
ultrasound or neurologic abnormalities such as seizures
may be present. Most affected cats are clinically dehy-
Unfortunately, most cats presenting with ATE display
tachypnea because of pain, making a definitive diagnosis drated and/or hypothermic. Rectal hypothermia was
of CHF very difficult without thoracic radiographs. In noted in 66% of the cats in which a rectal temperature
was measured in one large study. This was likely to be
addition to clinical signs associated with CHF, clinical
signs secondary to the specific tissue or organ embolized due to poor systemic perfusion rather than obstruction
of rectal perfusion since cats with forelimb emboli were
are to be expected.
Clinical signs that relate to the extremities have been also hypothermic (Smith et al. 2003).
characterized by the “five P’s”: Paralysis, Pain,
Pulselessness, Pallor, and Poikilothermia (Smith and DIFFERENTIAL DIAGNOSIS
Tobias 2004, Flanders 1986). The neuromuscular isch- Differential causes of acute posterior paresis include
emia secondary to vascular occlusion causes severe pain trauma, intervertebral disc extrusion, spinal lymphoma,