Page 675 - The Veterinary Care of the Horse

• respiration becomes even more of an effort

• pus collecting in the lower part of the chest cavity may prevent the lungs from expanding
VetBooks.ir fully; the patient becomes short of oxygen and may grunt with the pain and effort of

breathing

• adhesions may form between the surface of the lung and the chest wall and this makes
breathing and moving even more painful

• the horse may become toxic

• swelling may develop under the skin of the lowest part of the chest or abdomen (ventral
oedema)

• the horse may sweat and look very anxious

• there is usually significant weight loss.

Diagnosis

The history and the clinical signs are enough to make the vet consider a diagnosis of

pleuropneumonia or pleurisy. The examination is likely to include the following.

• Taking the horse’s temperature. However, fever is not a consistent sign and the
temperature may fluctuate.

• Listening to the chest with a stethoscope. Wheezing and crackling sounds may be heard
in the upper part of the chest and there is usually an absence of normal respiratory sounds

in the lower part of the chest. Sometimes there are ‘rubbing’ sounds due to the friction
between pleura on the chest wall and the surface of the lungs.

• Percussion (tapping) of the chest wall to determine the extent of the fluid in the chest.
Where the lungs are surrounded by pus or fluid, the sound generated will be dull. Where

they are surrounded by air, the sound will be hollow. This procedure is rarely resented by
a normal horse but is very uncomfortable for a horse with pleural inflammation.

• Ultrasonography. This is very useful for showing the presence, extent and nature of an

effusion. Adhesions and abscesses can also be identified.
• Taking a sample of fluid from the chest for microscopic examination and culture. The

ultrasound examination will show the best place to insert the cannula to obtain a sample.
This procedure is known as thoracocentesis.

• Performing a tracheal wash or bronchoalveolar lavage to identify the bacteria causing the
pneumonia and their antibiotic sensitivity.

• Blood tests. The total white cell count, serum amyloid A and fibrinogen will be raised.

• If radiographs are taken, the pus may show up as a horizontal line. This is only suitable