Page 893 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

868 CHAPTER 4

VetBooks.ir Diagnosis laparotomy. Thorough abdominal lavage can also
be performed during surgery. Peritoneal lavage can
Diagnosis is usually made by physical examination.
Any wound over the abdominal region should be
ing drains; however, these often quickly become
explored carefully to determine whether abdomi- be performed in the awake horse through indwell-
nal penetration has occurred, regardless of the size. blocked.
Ultrasonographic examination of the abdomen may
be useful in determining the organ damage that has Prognosis
occurred and whether there is haemoperitoneum or The prognosis for penetrating wounds of the abdo-
peritonitis present. Abdominocentesis is important men will vary according to the extent of damage to
to determine whether there has been intestinal leak- the underlying organs. If haemorrhage and infec-
age or haemoperitoneum. tion are controlled, splenic trauma may have a fair
to guarded prognosis. Cases in which there has been
Management perforation of the bowel or evisceration have a grave
In the acutely injured horse, attention must be prognosis. If the injury to the abdomen has not
paid to stabilising any cardiovascular compensa- traumatised the abdominal organs, the prognosis is
tion, especially in those cases where there has been improved. The wound in the abdominal wall usu-
splenic trauma, as is discussed for haemoperito- ally heals well, but there is a high risk of infection,
neum (see p. 865). Broad-spectrum antimicrobials abscess formation and peritonitis during the healing
(e.g. sodium/potassium penicillin 20,000–40,000 stages.
IU/kg i/v q6 h/procaine penicillin 20,000 IU/
kg i/m q12 h and gentamicin 6.6–8.8 mg/kg i/v DIAPHRAGMATIC HERNIA
q24 h) should be administered immediately and
should be continued until after the abdominal Definition/overview
wound has closed. Tetanus prophylaxis must also Diaphragmatic hernia results from herniation of
be considered. abdominal viscera into the thoracic cavity through a
The presence and extent of intestinal damage may diaphragmatic defect (Fig. 4.184). It usually leads to
only be determined by performing an exploratory hypoventilation and/or simple or strangulated intes-
tinal obstruction.

Aetiology/pathophysiology
4.184 Diaphragmatic hernia only occurs when a diaphrag-
matic defect is present. This defect can be congenital
or acquired. Congenital defects result from incom-
plete fusion of the pleuroperitoneal folds, causing
an enlarged oesophageal hiatus. External trauma,
strenuous exercise, GI distension or pregnancy can
increase the intrathoracic or intra-abdominal pres-
sure enough to create an acquired diaphragmatic
defect.
Herniated viscera decrease thoracic volume and
induce thoracic pain, often resulting in hypoventi-
lation. Herniation through a diaphragmatic defect
may result in simple or strangulating intestinal
Fig. 4.184 Post-mortem view of the thoracic surface obstruction.
of an equine diaphragm. Note the very large defect
in the ligamentous portion of this diaphragm. In this Clinical presentation
case both the small intestine and the large colon were Diaphragmatic hernias are most frequently observed
herniated into the thoracic cavity. in mature horses with a history of trauma, strenuous