Page 674 - The Veterinary Care of the Horse

PLEUROPNEUMONIA AND PLEURISY

VetBooks.ir The surface of the lungs and the inside of the chest cavity are lined with a membrane called

the pleura. Inflammation of these membranes is known as pleuritis or pleurisy. It is caused by
bacterial infection. Pus forms and collects at the bottom of the chest cavity. If the pleural

effusion develops secondary to pneumonia or a lung abscess, the condition is known as
pleuropneumonia.

Causes

• Stress, e.g. prolonged travelling is considered to be a major factor in triggering the
disease. When pleuropneumonia occurs following long journeys it is known as ‘Transit

or Shipping Fever’. During transport, horses may be exposed to warm temperatures and
high humidity. This combined with the fact that the horse has his head tied up for long

periods, compromises the immunity of the respiratory tract. As the horse is unable to
lower its head, the secretions of the airways are unable to drain and bacterial invasion

readily occurs.
• It may develop following viral or bacterial respiratory disease.

• A penetrating injury to the chest can cause pleurisy.

• The disease may develop after inhalation of foreign material into the lungs.
• Over-exertion, e.g. during racing, can predispose to pleuropneumonia.

CLINICAL SIGNS

The early signs include:

• raised temperature

• fast, shallow breathing
• a soft, painful cough

• +/− nasal discharge; if present, this can be watery, purulent or haemorrhagic, and it may

have an unpleasant smell
• poor appetite

• moving stiffly with small steps and a general reluctance to move

• abnormal posture with the elbows held outwards, away from the chest wall

• the condition is painful and affected animals are very miserable.

As the condition progresses: