Page 71 - Problem-Based Feline Medicine

5 – THE DYSPNEIC OR TACHYPNEIC CAT 63

Chlamydiosis can result in pneumonitis in kittens. ● Hilar lymphadenopathy supports fungal or
mycobacterial pneumonia, although infiltrative
Protozoal (toxoplasmosis) and parasitic (capillariasis,
lymphosarcoma may mimic this.
aelurostrongylosis, Paragonimus kellicotti) pneumonia
may occur. Hematology may reveal neutrophilia with or without a
left shift and toxic neutrophils (Doehle bodies, etc.).
Primary fungal pneumonia is mainly restricted to
● Low-grade non-responsive anemia and monocyto-
Cryptococcus neoformans. Infection can occur as a
sis may support chronicity.
sequel to fungal rhinosinusitis, or as primary pneumonia.
Hypoxemia (PaO < 80 mmHg on room air or SPO <
Viral interstitial pneumonia with feline calici virus 2 2
90%) may be present, with trends monitored by arterial
has been reported.
blood gas or pulse oximetry.
Less common fungal pneumonias include blastomy- ● Note: the oxygen saturation curve drops steeply
cosis, histoplasmosis, aspergillosis and candidiasis. with SPO values <90%.
2
Samples for cytology and culture can be obtained
Clinical signs using percutaneous lung aspiration, transtracheal
wash, unguided bronchioalveloar lavage or broncho-
A deep productive cough may be heard, although
scopic lavage. Cultures for aerobic and anaerobic bac-
coughing is not as common as in dogs.
teria should be performed and a fungal culture is
Fetid breath halitosis. indicated if infection is possible within the geograph-
ical region. Results of cultures must be evaluated in
Fever is common, although a subnormal body tempera-
light of other data including the concentration of bac-
ture can occur if the cat is septic.
teria, cytological findings, etc.
Inspiratory and expiratory dyspnea may be evi- ● Bacterial pneumonia is characterized bysuppurative
dent, often with open-mouth breathing. inflammation involving degenerative neutrophils
with intracellular bacteria.
Adventitial breath sounds, including crackles,
● Fungal and mycobacterial diseases have pyo-
wheezes, snaps and pops may be audible. Breath
granulomatous inflammation, with characteristic
sounds may be absent over areas of lobar consolidation.
organisms seen on routine or special stains.
Lethargy and anorexia are typically present, and
Cryptococcal titers may aid in the diagnosis.
weight loss and ill thrift may be evident if the pneumo-
nia is more chronic.
Differential diagnosis
Infectious pneumonia is uncommon in cats. A recent
Chronic small airway disease (feline asthma/ bronchi-
study of 39 cats with infectious pneumonia showed that
tis), pulmonary infiltrate with eosinophils (PIE) and
a substantial proportion had no clinical signs that were
lymphomatoid granulomatosis may share many similar
referable to the respiratory tract (36% of cats), they
historical, clinical and radiographic signs and need to be
lacked clinical signs of systemic illness (41%), and had
differentiated on clinical and histopathologic findings.
unremarkable findings on hematology (22%) and tho-
racic radiography (23%). Pulmonary neoplasia, either primary (squamous cell
carcinoma, bronchogenic carcinoma), or metastatic dis-
Diagnosis ease, is differentiated on histopathology.
Thoracic radiography findings include focal or gen- Treatment
eralized alveolar densities with air bronchograms, or
focal areas of complete consolidation. Bacterial pneumonia requires antimicrobial therapy.
● A ventral distribution of lesions may signal aspira- ● The parenteral route is used in debilitated or septic
tion as the cause of pneumonia. patients, and oral therapy in outpatients.
● A miliary interstitial pattern is seen with blastomy- ● Antibiotic selection is best based upon specific cul-
cosis. ture and sensitivity testing.