Dyspnea (Trouble Breathing) in Cats
A complete medical history and physical examination should be performed by your veterinarian. These diagnostic tests depend on the duration of signs, presence of other abnormalities, and what is found on the physical examination. They may include: Complete medical history and physical examination with emphasis on stethoscope examination (auscultation) of the heart and lungs. Identification of abnormal heart sounds such as heart murmurs or irregular heart rhythms (arrhythmia) is extremely important. During physical examination, your veterinarian will pay particular attention to your pet's breathing, the character of his/her heart and lung sounds, and mucous membrane color. Care must be taken not to stress your cat during the examination. Your cat should also be evaluated for weight loss and any concurrent disease.
Your veterinarian will want to know the following:
What medications your cat has been taking?
Is there a history of illness and if so, did your pet respond to therapy?
Has your cat has been anesthetized recently?
Is your cat intact or spayed?
Does your cat cough?
What circumstances make the breathing worse?
Has your cat ever had heartworms and are you giving preventative medication?
What is your cat's home environment and travel history?
Has there been any exposure to toxins (such as rat poison)?
Has your cat had any trauma?
Does your cat vomit or gag?
Diagnostic tests may include:
A chest radiograph (X-ray) to identify heart enlargement and fluid accumulation in the lung and to exclude some of the previously mentioned conditions that can mimic dyspnea.
Measurement of blood pressure with the special device that measures blood flow noninvasively. High and low blood pressure values may be identified because either can occur in patients with dyspnea.
An electrocardiogram (EKG) to identify heart enlargement and determine the electrical activity of the heart. The electrocardiogram is a noninvasive test done by attaching small contact electrodes to the limbs and body.
Ultrasound examination of the heart (echocardiogram) for a definitive diagnosis. This noninvasive test requires sophisticated equipment that creates high frequency sound waves much like the sonar of a submarine. An image of the heart is created. The echocardiogram is usually the test of choice to establish the final diagnosis of the cause of dyspnea, but this examination may require referral to a specialist.
Laboratory (blood) tests to evaluate other organ function, such as the kidney, and exclude anemia as a complicating factor. This can be critical to evaluating the effect of dyspnea on other organs and to monitor the effects of treatment.
A blood test to detect heartworm infection
A complete blood count (CBC) and serum biochemistry in sick or older animals.
Your veterinarian may recommend additional diagnostic tests to ensure optimal medical care. These are selected on a case-by-case basis if indicated from the examination, prior test results or lack of response. Tests may include:
Serologic tests for toxoplasmosis and systemic fungi
Respiratory cytology and culture if clinical signs and prior laboratory test results do not explain dyspnea with abnormal densities in the lungs. Samples for culture and respiratory cytology (characterizing the cells by looking at a sample under a microscope) may be obtained by using one of the five methods listed below; the method of choice depends on your veterinarians experience, availability of supplies and equipment, and nature of the lung disease.
Tracheal aspiration (removing a fluid sample using suction)
Bronchoscopy to obtain samples for culture and cytology and to provide a visual examination of the trachea and bronchopulmonary tree
Bronchoalveolar lavage (BAL), performed through a wedged bronchoscope, if no exudate (fluid high in protein) is observed in the trachea and main bronchi
A fine needle aspirate (FNA) of the lung is an alternative for assessment of the dyspneic patient with some types of lung disease.
Endoscopy. This direct visualization of the upper airways, trachea and bronchi is indicted when intraluminal masses, foreign body, Osleri osleri (a type of traveling parasite) nodules or other causes of unexplained airway obstruction or inflammation are suspected.
Biopsy of the lung (by thoracoscopy or mini-thoracotomy). This test is sometimes the only method for attaining a diagnosis in disseminated pulmonary disease, especially interstitial disorders, unexplained by previous less-invasive test results. When a singular localized lung lesion is evident and either a foreign body or tumor is suspected consider surgical removal of the affected lobe.
Direct fecal smears and special sedimentation methods (Baerman), along with fecal flotation to screen for lungworms, in pets that have radiographs that are compatible with lungworm infection
Fluoroscopy or endoscopy to demonstrate dynamic collapse of a major airway when it cannot be shown by routine X-ray films
Cytologic evaluation of conjunctival membranes (for distemper inclusions), skin ulcers (for systemic fungi) and enlarged lymph nodes (for infection or tumors)
Esophagoscopy to diagnose esophageal-tracheal fistula or causes of aspiration pneumonia
Specialized blood tests, such as blood taurine, in cases of dilated cardiomyopathy
Thyroid tests to exclude abnormal function of the thyroid gland
Blood cultures in suspected infection of the heart valves
Consultation with appropriate specialists as needed