Page 94 - Problem-Based Feline Medicine

86 PART 2 CAT WITH LOWER RESPIRATORY TRACT OR CARDIAC SIGNS

Classical signs—Cont’d ● On thoracocentesis there is a small volume of effu-
sion which is commonly a sterile inflammatory
● Muffled heart and/or lung sounds ventrally. exudate, and is often grossly serous or hemorrhagic
● Orthopnea (positional dyspnea with rather than purulent.
reluctance to lie in lateral recumbency).
Cytology and culture samples from percutaneous lung
aspiration, transtracheal wash or bronchoscopic lavage
See main reference on page 62 for details (The
may be diagnostic. Fungal, aerobic and anaerobic bacter-
Dyspneic or Tachypneic Cat).
ial cultures are generally submitted.
Clinical signs Cryptococcal titers may aid in the diagnosis.
Infectious pneumonia is rare in cats.
Differential diagnosis
A deep productive cough may be present, which gener-
Other causes of pleural effusion, such as pyothorax,
ally is infrequent unless the pneumonia is secondary to
congestive heart failure, chylothorax, FIP and mediasti-
bronchitis (see page 104, The Coughing Cat).
nal masses may mimic the parapneumonic effusion of
Inspiratory and expiratory dyspnea, often with some pneumonias. Typically, pneumonic patients are
open-mouth breathing is present when pneumonia is more severely dyspneic than would be attributed to the
severe and associated with a parapneumonia pleural subtle effusion, because of the associated compromise
effusion. of the lung parenchyma in pneumonia, which is not
usually found in other causes of effusion.
Adventitial breath sounds, including crackles,
wheezes, snaps and pops are audible. Each of the infectious pneumonias can have overlap-
ping features.
Heart sounds may be muffled and lung sounds poorly
audible ventrally, although the effusion volume is usu-
ally small.
Treatment
Systemic signs include lethargy, anorexia, weight loss,
Bacterial pneumonia
fever and ill thrift.
● Appropriate antimicrobial therapy is the mainstay
Halitosis may be noted. of therapy. The parenteral route is used if the patient
is debilitated or septic. The oral route can be used
Deep chest excursion and diminished oral airflow
with outpatients. Antibiotic selection is best based
occurs when parapneumonic pleural effusion is present.
upon specific culture and sensitivity testing.
Geographical location and other signs might suggest the ● Pending culture results, some therapeutic decisions
etiology of the pneumonia, including bacterial, fungal, may be based upon Gram stain results.
viral and Chlamydophila felis pneumonitis. – Gram-positive cocci – ampicillin, amoxicillin,
amoxicillin-clavulanic acid, trimethoprim-sulfa,
cephalosporins.
Diagnosis
– Gram-negative rods – chloramphenicol,
Thoracic radiography reveals alveolar densities (focal trimethoprim-sulfa, fluoroquinolones.
or generalized) and possible areas of complete consoli- – Bordetella – tetracycline, doxycyline, chloram-
dation. There is subtle radiographic evidence (e.g. pleu- phenicol, fluoroquinolones.
ral fissure lines) of a small-volume pleural effusion. – Suspected anaerobes – clindamycin, amoxi-
● Hilar lymphadenopathy supports fungal or cillin-clavulanic acid, metronidazole.
mycobacterial pneumonia.
Fungal pneumonia
On hematology neutrophilia is common, with or ● Systemic itraconazole given at 5–10 mg/kg PO
without a left shift or signs of toxicity. daily is the drug of choice. If there are CNS signs
● Low-grade, non-responsive anemia and monocyto- with cryptococcosis, use fluconazole (2.5–5.0 mg/kg
sis may support chronicity. PO daily) as it crosses the blood–brain barrier.