Cardiogenic causes include any of the diseases of the heart that allow the accumulation of fluid in the lungs. These are typically those that affect the workings of the left side of the heart, as it’s this side’s failure that’s inextricably intertwined with the accumulation of fluid in the lungs.
Consider these, several of its more common causes of cardiogenic pulmonary edema:
- Chronic valve disease (especially of the left atrioventricular or mitral valve)
- Dilated cardiomyopathy in dogs
The following comprise the most common of pulmonary edema’s non-cardiogenic causes:
- Cancer of the lungs
- Head trauma
- Acute lung injury
- ARDS (acute respiratory distress syndrome)
What to Watch For
Dogs with pulmonary edema typically present with signs consistent with lung disease, including the following:
- Difficulty breathing (increased respiratory rate or effort)
- Blue tongue and/or mucous membranes
Diagnosis of Pulmonary Edema in Dogs
Physical examination, including listening to the chest with a stethoscope (auscultation), is a necessary first step. Abnormal lung sounds consistent with pulmonary edema (wet, crackly sounds) are typically observed, though these can sometimes be obscured by the loudness of a heart murmur or other abnormal cardiac sound. If a cardiogenic cause is suspected, careful attention to heart sounds is crucial, though these may not always be present.
To confirm and definitively diagnose pulmonary edema, chest x-rays are typically taken. These will elucidate any areas of fluid accumulation within the lungs.
Abnormalities in the heart that may be related to the pulmonary edema’s underlying causes may or may not be visible on chest X-rays. For this reason, an echocardiogram (ultrasound of the heart) is strongly recommended for pets suspected of suffering from a cardiogenic cause.
Standard tests for all pulmonary edema patients also includes a CBC, blood chemistry screen and urinalysis.
Treatment of Pulmonary Edema in Dogs
Treatment of pets with pulmonary edema depends to a large extent on its cause, as treatment of any underlying disease is the primary approach in all cases. Nonetheless, there is a set approach to treatment that involves a three-pronged strategy:
- Patient stabilization: Most pulmonary patients arrive in distress. They are typically treated with oxygen therapy and drugs to help them relax so they can properly oxygenate their tissues.
- Resolution of the edema: Treatment with diuretics and other drugs can help remove the fluid from the lungs (temporarily, at least).
- Treat the underlying cause: This three-pronged approach always culminates in treating the causative disease. Without this step, there can be no expectation of long-term survival.
When the cause of pulmonary edema cannot be isolated, or when it’s deemed untreatable, there are nonetheless some well-established methods to help control the accumulation of fluid in the lung tissue. Diuretics are the mainstay of treatment in these cases, as are other drugs to help control other issues associated with the underlying disease.
For example, most cardiac diseases in pets are considered manageable but not curable. These chronic illnesses may require long-term therapy with diuretic drugs along with any additional drugs to control the heart disease itself.
The veterinary cost of pulmonary edema varies depending on the cost of the underlying disease’s treatment. In general, however, treatment of an acute event (such as trauma) is less expensive than the long-term treatment of cardiac diseases, which may cost hundreds of dollars a month in medications alone.
Prevention of Pulmonary Edema in Dogs
As many of its underlying causes are either inherited or traumatic, pulmonary edema is generally not considered a preventable condition. Nonetheless, many dogs with underlying heart diseases can be successfully managed so that their conditions never progress to pulmonary edema (except, perhaps, in their very last stages).
References for of Pulmonary Edema in Dogs
- Goodwin JK, Strickland KN. The emergency management of dogs and cats with congestive heart failure. Vet Med 1998;93:818-822.
- Hansen B, DeFrancesco T. Relationship between hydration estimate and body weight change after fluid therapy in critically ill dogs and cats. J Vet Emerg Crit Care 2002;12(4):235-43.
- Muir WW, DiBartola SP. Fluid therapy. In: Kirk RW, ed. Current veterinary therapy VIII. Philadelphia, Pa.: WB Saunders Co, 1983;33.
- Sisson D, Kittleson MD. Management of heart failure: principles of treatment, therapeutic strategies, and pharmacology. In: Fox PR, Sisson D, Moise NS, eds. Textbook of canine and feline cardiology. Philadelphia, Pa: WB Saunders Co, 1999.
- Ware WA, Bonagura JD. Pulmonary edema. In: Fox PR, Sisson D, Moise NS, eds. Textbook of canine and feline cardiology. Philadelphia, Pa: WB Saunders Co, 1999.