Many times we see patients with an existing heart murmur that present with respiratory signs.
Many geriatric patients have acquired valvular diseases and when they are presented with a cough it is tempting to attribute the signs to heart failure, especially if there is cardiomegaly  on the radiographs.
In both pulmonary edema and small airway disease there are peribronchial changes and interstitial to alveolar infiltrates.
If these changes result from cardiogenic pulmonary edema there should be a left atrial enlargement (usually a profound one) and pulmonary venous congestion. If those are not visible than the changes probably indicate an airway disease.
The example below is  a 10 year old male castrated Tibetan terrier which was presented with acute lethargy,  and cough. A 2/6 systolic heart murmur was auscultated.

Do the clinical signs result from a deterioration of the preexisting cardiac disease or  do they result from an airway disease?
Use the comments link above to submit your answers. The answer will be available in a few days in the comments link.
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Comments

Noa Meir, VMD

Thu, 20 Mar 2008 14:24:42

There is interstitial and alveolar pattern in the caudal lung field, mostly in the ventral right lung lobe.
The heart does look enlarged both on the lateral and VD, but the pulmonary vessels seem to be in a normal size, and the left atrium is only mildly enlarged.
With pulmonary edema I would expect a more dorsal distribution.
So my guess is an airway disease rather than pulmonary edema...

 

Daniel Cohen

Sun, 23 Mar 2008 19:39:01

I agree with the above comment that the changes are probably due to an airway disease.
A clue for that would also be the fact that the murmur is relatively a low grade one. With heart failure I would expect it to be 3/6 and higher.

 

Michal Hess

Mon, 31 Mar 2008 18:27:57

There is mild cardiomegaly with dorsal displacement of the trachea on the lateral view.
There is a mild diffuse bronchial pattern.
There are interstitial to alveolar infiltrates in the right middle lung lobe visible on the VD view and the left lateral view (why are those visible on the LL view and not on the RL view? see the discussion of case number 12).
This dog has evidence of heart disease- a heart murmur was revealed on physical exam and his heart is mildly enlarged on the radiographs. With a history of cough, it is tempting to suggest heart failure with resulting pulmonary edema as the cause of the cough. But the left atrium is not enlarged. In the case of pulmonary edema, the left atrium must be enlarged and the enlargement is usually profound when cardiogenic pulmonary edema is present. (On rare occasions there will not be a left atrial enlargement- for example acute cases of congestive heart failure, e.g ruptured chordae tendinae). Therefore, the cough must be due to other causes.
Small airway disease is very likely. This is an example of small airway disease in a geriatric dog that also has compensated mitral valve insufficiency.

 



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