Page 346 - Clinical Small Animal Internal Medicine

314 Section 4 Respiratory Disease

Table 32.1 Recognized risk factors for PTE disease processes with a known association with thromboembolic disease in the dog. Those
VetBooks.ir included
conditions also associated with an increased risk in the cat are marked by an asterisk. Proposed mechanisms for these risk factors are

Hypercoagulable Vascular flow Endothelial injury/
Disease process risk factor state abnormalities/stasis dysfunction
*Corticosteroid administration ✓
Diabetes mellitus ✓
Dirofilariasis ✓ ✓
*DIC (secondary to other disease) ✓
Endocarditis ✓ ✓
(tricuspid/pulmonic)
*Feline infectious peritonitis ✓ ✓
Hyperadrenocorticism ✓
Hypothyroidism ✓
*IMHA ✓ ?
*Indwelling venous catheters ✓ ✓
Myocardial disease ✓ ✓ ✓
*Neoplasia ✓ ✓
*Pancreatitis ✓ ✓
*Protein‐losing enteropathy ✓
*Renal amyloidosis/PLN ✓
*Sepsis ✓ ✓
*Surgery/trauma ✓ ✓ ✓
Source: Adapted from Goggs et al. [1].
DIC, disseminated intravascular coagulation; IMHA, immune‐mediated hemolytic anemia; PLN, protein‐losing nephropathy.

Clinical Signs may be clinical signs attributable to the predisposing
intercurrent disease.
The clinical signs of PTE are variable, inconsistent, and Clinicians should suspect PTE in patients with no
nonspecific. The degree of physiologic impairment and history of cardiopulmonary disease who develop res­
thus the severity of clinical signs reflect both the mag­ piratory distress acutely, particularly where known risk
nitude of the PTE and the patient’s ability to compen­ factors exist.
sate. The most common signs are dyspnea, tachypnea,
and depression. Other signs include coughing, hemop­ Diagnosis
tysis, cyanosis, syncope, collapse, and sudden death. In
dyspneic patients, physical examination may reveal Suggested Diagnostic Approach
harsh lung sounds and crackles suggestive of pulmo­
nary edema. Occasionally, lung and heart sounds may Pulmonary thromboembolism is commonly suspected
be muffled due to pleural effusion or in very rare cases but infrequently conclusively diagnosed, probably
pneumothorax. In eupneic patients, lung field ausculta­ because of variability in clinical signs, low test specific­
tion will likely be normal. On cardiac auscultation, ity, and limited availability of definitive diagnostics.
tachycardia with a split second heart sound may be Establishing a clear diagnosis of PTE remains a challenge
noted or, more commonly, a loud second heart in veterinary medicine, even with a logical approach. In
sound associated with pulmonary hypertension. Signs human medicine, where definitive diagnostics are widely
compatible with backward heart failure (jugular disten­ available, the major challenge is to identify which patients
sion or pulsation, ascites) or forward heart failure (poor to prioritize for definitive imaging studies. This need has
peripheral pulse quality, pallor, prolonged capillary driven the development of clinical prediction rules and
refill time) may be present. Complicating the picture diagnostic algorithms.