Page 83 - Problem-Based Feline Medicine

6 – THE CAT WITH HYDROTHORAX 75

works very well. Local anesthetic blockade may or hydrostatic pressure (i.e., heart failure), or occur
may not be required, depending on the level of res- in acute inflammatory disease prior to exudation.
piratory distress. – Exudates vary from white to red, turbid to
● Technique opaque, are high protein (> 3.0 g/L), and highly
9
– Have the patient sitting, standing or in sternal cellular (TNCC > 7.0 × 10 /L. They are associ-
recumbency. ated with inflammatory or neoplastic disease.
– Clip and aseptically prepare the 4th–7th inter- ● Thoracic radiography should be performed after
costal space – above and below the costochondral thoracocentesis to help to assess the success of
junction. pleural drainage and to facilitate imaging of
– Infiltrate around the 7th intercostals space just mediastinal masses, pulmonary lesions or cardiac
above the costochondral junction with local changes that may have contributed to the effusion.
anesthetic field block (optional if peracute and These changes may have been previously masked
in severe distress), using 2% lidocaine or 2% by the presence of the effusion.
mepivicaine. Block the skin, muscles and pari-
Other imaging may be required depending on the char-
etal pleura, as this is the most painful area.
acter of the effusion (i.e., cardiac ultrasound if transu-
– Use 25 gauge needles and INJECT SLOWLY!
date, lymphangiography if chylous effusion, etc.).
– Place the catheter at the 7th intercostal space
just above the costochondral junction. With a
syringe on the catheter, aspirate using minimal
DISEASES CAUSING HYDROTHORAX
negative pressure.
– Direct the catheter ventrally for fluid removal. If
drainage is inadequate use a butterfly needle and PYOTHORAX***
aspirate the intercostal junction from the 4th–6th
intercostals or place a chest drain.
Classical signs
● Fluid analysis should be performed to determine
● Dyspnea with exaggerated chest
the etiology of the hydrothorax.
– Cytologic, clinicopathologic, and bacteriologic excursions/poor airflow.
● Muffled heart and/or lung sounds ventrally.
analysis will help determine the etiology.
● Orthopnea (positional dyspnea – reluctance
Common assessments include physical param-
eters such as color, transparency, specific grav- to lay in lateral recumbency).
● Signs of chronic disease (weight loss, ill-
ity (SG), total protein (TP), and total nucleated
cell counts (TNCC) and some biochemical thrift), and fever are common.
● Grossly purulent exudate in the pleural cavity.
parameters such as triglyceride, cholesterol,
● History of fight wounds several weeks
glucose and certain enzyme levels, such as lac-
tate dehydrogenase (LDH). previous to presentation.
– Hemothorax is characterized by frank blood.
Erythrophagocytosis which is usually defibri-
nated may be evident cytologically, and gener- Pathogenesis
ally has a hematocrit lower than peripheral
Septic bacterial infection of the pleural cavity results in
blood.
purulent exudation.
– Transudates are clear and colorless with a spe-
cific gravity (SG) </= 1.013, total protein (TP) Multiple routes of infection, include:
< 2.5 g/L and low cellularity (total nucleated ● Hematogeneous with systemic sepsis spread via
9
cell count [TNCC] < 1.5 × 10 /L). vasculature or lymphatics.
– Modified transudates are typically straw-colored ● Extension from an adjacent infected structure,
to pink-white. Total protein is between 2.5 and including parapneumonic spread from lung infec-
9
4.0 g/L, and TNCC between 1.0 and 7.0 × 10 /L. tion or abscess, or from esophageal rupture, or
Modified transudates result from transudates mediastinitis.
modified from chronicity, prolonged increased