Page 365 - Problem-Based Feline Medicine

18 – THE THIN, INAPPETENT CAT 357

● Neoplasia and fungal causes are unlikely if the clin- Clinical signs
ical signs have been constant for a protracted period
Although signs of respiratory distress may appear
(1–2 years).
acute, the disease process is often more chronic.
A thorough examination of the oral cavity and phar-
Clinical signs will vary with the quantity of fluid present.
ynx should be made whilst the cat is anesthetized to
● Cats adjust to the decreased lung volume, and
exclude congenital and traumatic palate defects, dental
distress is not usually apparent until late in the
disease, nasopharyngeal polyps and neoplasia as a
disease.
cause.
● Tachypnea and dyspnea are often present.
Radiographic evidence of bilateral fluid density in ● If ventilation is severely impaired, cyanosis may be
nasal passages often extending into the frontal sinuses noted.
is typical.
Auscultation usually reveals decreased breath sounds
● Occasionally bone destruction is seen on radi-
(muffled and dull) ventrally.
ographs.
● Occasionally fluid may accumulate in focal areas,
Cytology of the nasal discharge reveals neutrophils, and unilaterally rather than bilaterally.
bacteria, and the absence of neoplastic or fungal ● Heart sounds may be muffled.
elements.
The thorax may be dull on percussion.
Rhinoscopy (anterior and posterior) will permit visual
Weight loss in usually present, accompanied by inap-
examination and flushing of the nasal cavity, and facil-
petence as the respiratory difficulty increases.
itate nasal biopsy.
● Blind biopsy or traumatic flushing may be used to Clinical signs to a certain degree will depend on the
obtain biopsy material from the nasal cavity. underlying cause of the pleural effusion.
● It is extremely difficult to definitively exclude ● Possible causes of chylothorax include neoplasia,
neoplasia in these cases. heart failure, trauma and hyperthyroidism, although
– A diagnosis should not be made on cytology in many cases the underlying etiology is not deter-
alone, because both neoplasia and fungal disease mined despite extensive investigation (termed idio-
frequently reveal only neutrophils and bacteria pathic chylothorax).
on cytologic examination.
– Rhinotomy and biopsy may be necessary to
definitively exclude neoplasia, particularly in Diagnosis
cases with suggestive clinical signs.
The presence of a pleural effusion may be confirmed
Respiratory virus status may be evaluated by virus iso- radiographically or ultrasonographically.
lation from oropharyngeal and nasal swabs. ● Care should be taken in handling and position-
ing cats with respiratory distress, and thoraco-
FeLV and FIV status should be assessed and other
centesis may be required to stabilize the cat
causes of immunosuppression should be excluded.
prior to these procedures.
● Radiographic evidence of a pleural effusion
CHYLOTHORAX includes:
– Presence of pleural fissure lines.
Classical signs – Separation of lung borders from the thoracic
wall and rounding of edges of the lung lobes.
● Respiratory distress – tachypnea, dyspnea
– Loss of cardiac silhouette.
and open mouth breathing.
● Weight loss. Thoracocentesis with biochemical and cytological
● Inappetence. analysis of thoracic fluid is required for definitive
diagnosis:
See main references on page 77 for details (The Cat ● Chylous fluid is usually a white “milky” fluid.
With Hydrothorax). – It may be slightly pink on repeated aspirations.