Page 64 - Problem-Based Feline Medicine

56 PART 2 CAT WITH LOWER RESPIRATORY TRACT OR CARDIAC SIGNS

Open-mouth breathing may occur especially with stress. Clinical signs
Coughing may be present if Bordetella bronchiseptica Mediastinal masses are often thymomas, thymic lym-
or herpes virus are involved. phoma, or mediastinal lymphoma. Occasionally, ectopic
thyroid adenocarcinoma may create a space-occupying
Ocular discharge, conjunctivitis and chemosis occur
mass of the mediastinum. Pleural masses include
with acute upper respiratory tract infection with calici
mesotheliomas, osteosarcoma or chondrosarcoma of
or herpes virus and Chlamydophila felis.
the ribs or sternabrae.
Stertorus respiration (snoring) may be evident.
Signs are related to the space-occupying nature of the
Nasal distortion may occur with cryptococcosis, neo- mass, or to obstruction of lymphatic drainage, leading
plasia or rarely with chronic secondary bacterial rhinitis. to pleural effusion.
Orthopnea (dyspnea worsened by lateral recumbency),
Diagnosis tachypnea, minimal airflow with increased chest excur-
sions, muffled heart and lung sounds, or asymmetrical
Signalment, clinical signs and history are often sugges-
sounds if the heart is displaced laterally.
tive of the etiology. In acute upper respiratory tract
infection, multiple cats in the home are often affected. Extraluminal compression of the trachea can cause dys-
pnea and cough.
Radiographic findings:
● Usually there is loss of lucency in the nasal cavity Compression of the anterior chest wall may reveal
resulting from fluid (fluid density). In chronic nasal decreased compliance.
diseases causing dyspnea, there is often osteolysis
of the nasal turbinates. Lysis tends to be asymmet-
rical with neoplasia and is more often symmetrical Diagnosis
with cryptococcosis and chronic bacterial rhinitis
Thoracic radiography may reveal the mass lesion or
secondary to viral disease.
the secondary pleural effusion.
Culture or PCR is now available for calicivirus, her-
Thoracic ultrasound can be extremely useful.
pesvirus and Chlamydophila felis. Bacterial culture
● Small mediastinal masses surrounded by aerated
may be useful to identify bacteria in secondary bacter-
lung may not be visible from a paracostal approach,
ial rhinitis so the most appropriate antibacterial therapy
and may require a thoracic inlet window.
can be selected, e.g. Pasteurella spp.
● Transesophageal ultrasonography is excellent for
Cats with cryptococcosis frequently have nasal distor- demonstrating mediastinal masses, but requires
tion over the bridge of the nose or a polyp-like mass specialized equipment and general anesthesia.
visible in the nasal cavity. Diagnosis is based on cytol-
Analysis of the thoracocentesis fluid may be diagnos-
ogy, histology or a positive serology titer.
tic on the rare occasions that the neoplasm has exfoli-
Neoplasia is most reliably diagnosed on histology, ated into the fluid. Pleural effusions associated with
although a cytological sample may be diagnostic. tumors are usually modified transudates, but may be
transudates, exudates or chylous. Surgical or ultra-
PLEURAL/MEDIASTINAL MASSES* sound-guided biopsy of the mass is usually required for
a definitive diagnosis.
Classical signs Mediastinal lymphoma occasionally has hypercalcemia
as a paraneoplastic syndrome.
● Muffled heart and lung sounds ventrally or
asymmetrical sounds.
● Dyspnea characterized by excessive chest Differential diagnosis
excursions with poor airflow.
● Orthopnea (positional dyspnea). Other causes of pleural effusion need to be differenti-
ated. Chylothorax is more commonly idiopathic and