Page 362 - Feline Cardiology

Chapter 24: Comorbidities 377

Dietary, parasitic, and other inciting causes of intestinal Instead of inflammatory skin disease, cats may show
inflammation may produce clinical signs and histologic hair loss due to behavioral disorders or to internal dis-
lesions suggestive of IBD. Such disorders require proper comfort including anal sac impaction (Waisglass et al.
and comprehensive diagnostic investigation, and correc- 2006) or ureteral obstruction (Polzin 2010). Therefore,
tion if a disorder is found, before a diagnosis of idio- such disorders must be considered, identified, and cor-
pathic IBD can be made. Many clinicians advocate rected to avoid misdiagnosis and mistreatment with
empirical deworming regardless of fecal cytology results glucocorticoids, particularly when a cat also has concur-
prior to endoscopy, and certainly prior to administra- rent heart disease and may not tolerate such therapy.
tion of immunosuppressive agents. When idiopathic Topical treatments, such as shampoos, rinses, sprays,
IBD has been identified in a cat with concurrent heart and topical wipes can be helpful for cats with inflamma-
disease, there are several alternatives to prednisolone tory skin disease and concurrent heart disease, and
(the active form, which is more likely to be effective in barring a cat’s dislike of a particular treatment (e.g.,
cats that cannot hepatically transform prednisone) or bathing), this approach carries minimal risk of cardio-
sustained-release/repositol glucocorticoid injections. vascular detriment. However, topical therapies that
Budesonide is a corticosteroid with marked first-pass contain glucocorticoids also may exert systemic gluco-
hepatic elimination and therefore reduced systemic cor- corticoid effects and should be used sparingly if at all.
ticosteroid effects. It may be given orally (0.5 mg/cat;
compounding is necessary because the product is avail- CARDIAC DISEASE AND UNRELATED
able only as a 3 mg capsule), or as an enema (0.5–1 mg/ PLEURAL EFFUSION
cat; enemas are 2 mg each) if the intestinal lesion pre-
dominantly affects the large bowel. Alternatively, cyclo- When pleural effusion is caused by a noncardiac disor-
sporine (e.g., Atopica, Neoral; 2–5 mg/kg PO q 12h) may der (e.g., mediastinal lymphoma, idiopathic chylotho-
be effective and anecdotal reports of a positive response rax, etc.) but the patient also has concurrent, unrelated
have been noted. Chlorambucil (2 mg/cat PO q 48h) is heart disease, it may be difficult to feel certain that the
routinely used in cats with severe inflammatory bowel pleural effusion is—or is not—caused by cardiac disease.
disease and/or histologic changes consistent with low- Certain guidelines are helpful: in the absence of atrial
grade intestinal lymphoma. Results have been variable, enlargement on an echocardiogram, it is unlikely that
with some cats demonstrating a good response and pleural effusion is cardiogenic. Lack of cardiomegaly on
others responding minimally (Richter 2003). Any of these thoracic radiographs likewise makes a cardiogenic cause
treatments can be used, with minimal cardiovascular of pleural effusion less likely, but the conclusion is less
effect compared to oral or parenteral glucocorticoids. definitive than the echocardiographic absence of atrial
enlargement. Echocardiographic measurements of left
Immune-mediated Liver Disease, Lymphocytic- ventricular or right ventricular wall thickness are Comorbidities
Plasmacytic Cholangiohepatitis unlikely to provide information that is more useful than
The principles and recommendations listed for IBD atrial dimensions because substantial differences in ven-
(above) may also be applied to immune-mediated chol- tricular wall compliance (degrees of restrictive physiol-
angiohepatitis. As an alternative to immune suppression ogy) may be present with only minimal difference in
with cyclosporine or chlorambucil, methotrexate 2.5 wall thickness. For example, there may be increased ven-
2
mg/m PO q 48–72h has been advocated for lymphocytic- tricular wall thickness but normal diastolic filling pres-
plasmacytic cholangiohepatitis. sures and a low likelihood of heart failure, or the ventricle
may be minimally thick but very stiff in cases of restric-
Inflammatory or Immune-mediated tive cardiomyopathy. The character of the pleural effu-
Skin Disease sion may be helpful: purulent effusions are not
Glucocorticoids are perhaps used more for skin disease cardiogenic, and hemorrhagic effusions are also not car-
than diseases of any other organ in small animal medi- diogenic unless the patient has marked atrial enlarge-
cine. In cats with concurrent heart disease, seeking ment and the thoracocentesis needle has inadvertently
underlying causes of skin disorders and choosing other punctured an atrium. Milky/chylous effusions and
options for treatment becomes especially important. modified transudates are nonspecific and may be caused
Empirical and vigilant antiparasitic (anti-flea) treat- by heart disease or extracardiac disorders. Definitive
ment is essential, and many dermatologists advocate confirmation may be obtained via measurement of
early empirical treatment for other ectoparasites (e.g., central venous pressure (CVP) which, if above 8 cm H 2 O
Cheyletiella, Notoedres) when consistent with clinical postcentesis, is consistent with right-sided congestive
signs. heart failure and a cardiogenic source of the effusion. As