Page 225 - BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery, 2nd Edition

BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery

regurgitation, dogs with a hiatal hernia had slow second-
ary wave development after swallowing a bolus of food,
VetBooks.ir (Stickle et al., 1992). It was hypothesized that the oesopha-
with poor oesophageal tone and oesophageal redundancy
geal disorder was secondary to hiatal hernia because
these signs resolved in those animals where surgical
correction was performed, but remained in those that were
managed medically. However, all of these radiographic
signs were also seen in a high proportion (38–69%) of
clinically normal Shar-Peis, some of which showed sponta-
neous resolution of these findings as they grew older (6–12
months old), so the significance is not clear.
Segmental or generalized oesophageal hypomotility
and oesophageal redundancy are common in the Shar-
Pei breed, but may be incidental radiographic findings,
not associated with any clinical signs. In addition, a
congenital idiopathic form of megaoesophagus has
also been described in the Shar-Pei, with similar clinical 17.7 Hiatal hernia: lateral view of the abdomen and caudal thorax
following administration of barium suspension. There is
signs in young (3-month-old) animals (Knowles et al., herniation of the stomach through the oesophageal hiatus.
1990). Fluoroscopy should allow differentiation between
these conditions.
junction remains in its normal position and the stomach
Diagnosis: The intermittent nature of the herniation makes protrudes into the thorax (Miles et al., 1988).
diagnosis difficult. Clinical signs may be observed any Oesophagoscopy may reveal mucosal hyperaemia,
time after weaning in congenital hiatal hernia, and are inflammation and ulceration of the distal oesophagus
usually present before 1 year old. Clinical signs associated (Merdan Dhein et al., 1980). A caudal oesophageal sphinc-
with acquired hiatal hernia may be seen at any time, ter that lacks tone, or that is displaced to one side, requir-
depending on the nature of the predisposing factors. ing redirection of the tip of the endoscope to enter the
Clinical signs include hypersalivation, regurgitation or stomach, may also be appreciated (Lorinson and Bright,
vomiting, haematemesis, dysphagia, dyspnoea or ortho- 1998). However, endoscopically apparent oesophagitis is
pnoea and exercise intolerance (Ellison et al., 1987; not noted in all cases.
Prymak et al., 1989; Callan et al., 1993). Regurgitation or Oesophageal manometry may be used to examine the
vomiting may be exacerbated by excitement or exercise. pressure at the caudal oesophageal sphincter, which is
An attempt should be made to rule out predisposing reduced in cases of sliding axial hernias, but not in cases
causes, particularly respiratory tract disease. Some of para-oesophageal hernias (Ellison et al., 1987). However,
animals show no clinical signs and the hernia is discovered this is primarily a research tool rather than a clinical
as an incidental clinical or post-mortem finding. diagnostic tool.
Imaging is the most useful diagnostic test, with survey
radiographs, oesophagography and fluoroscopy all playing Treatment: The difficulty in understanding the complex
a useful role. Some reports indicate that a diagnosis can nature and interplay of the various pathophysiological
be reached with survey radiographs in all cases (Callan et events is reflected in the relatively poor success of medical
al., 1993), whereas other reports suggest that contrast and surgical management in many reports. This has been
radiographic studies are required in a high proportion of hindered by the rarity of the condition and the tendency to
cases (White, 1993; Lorinson and Bright, 1998). adopt surgical techniques from human medicine, which
The most consistent radiographic sign of herniation is have subsequently been found to be inappropriate.
displacement of the stomach. Radiography may reveal a
soft tissue opacity in the region of the distal oesophagus, General approach to therapy: Gastro-oesophageal reflux
immediately cranial to the left diaphragmatic crus, and a associated with hiatal herniation may be treated medically
gas-filled oesophagus. This opacity may be identified as or surgically. In animals with acquired hiatal hernia
stomach if it is gas-filled and reveals rugal folds. The secondary to other diseases, these diseases should be
displacement of the stomach produces an abnormal treated first before considering surgical management of
‘stretched’ appearance to the remaining portions of the the hiatal hernia. In cases of congenital hiatal hernia,
stomach in the abdomen. An alveolar pattern in the depend- surgery is indicated for animals that show no improvement
ent portions of the lung lobes, which may progress to lobar following medical therapy, or which have frequent relapses
consolidation, is consistent with aspiration pneumonia. following cessation of therapy.
A positive contrast oesophagogram, using barium The most appropriate management of the asympto-
liquid or paste, may show dilatation of the caudal oesoph- matic animal with hiatal hernia is not known (Bright et al.,
agus and retention of barium in this location, and cranial 1990). It is not known whether these animals have a non-
displacement of the gastro-oesophageal junction, cardia progressive and potentially self-resolving hernia (e.g. as in
or fundus into the thorax (Figure 17.7). Fluoroscopy, follow- some young Shar-Peis), in which case no therapy would be
ing the administration of barium and food, is the most appropriate, or whether clinical signs associated with the
reliable method for identifying intermittent hiatal hernia - hernia may develop, in which case preventive therapy
tion and allows assessment of oesophageal motility. might be appropriate.
Fluoroscopy may reveal gastro-oesophageal reflux, hernia - The aims of therapy are:
tion of the stomach, a patulous gastro-oesophageal
junction and decreased primary or secondary oesoph- • Amelioration of signs of gastro-oesophageal reflux
ageal contractions (Prymak et al., 1989). In a para- • Restoration of normal caudal oesophageal sphincter
oesophageal hiatal hernia, the gastro-oesophageal function

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