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Definitive diagnosis requires endoscopy (cannot do in foals as need to starve prior to exam)
Definitive diagnosis requires endoscopy (cannot do in foals as need to starve prior to exam)
''EGUS was recently discussed at the 2010 Annual meeting between the Equine Insurers Forum (EIF) and the British Equine Veterinary Association (BEVA). The EIF maintained that in order to support claims for the long term costs associated with treatment of EGUS, there would be a requirement for veterinary surgeons to make a definitive diagnosis prior to prescribing omeprazole.(BEVA)''
''EGUS was recently discussed at the 2010 Annual meeting between the Equine Insurers Forum (EIF) and the British Equine Veterinary Association (BEVA). The EIF maintained that in order to support claims for the long term costs associated with treatment of EGUS, there would be a requirement for veterinary surgeons to make a definitive diagnosis prior to prescribing omeprazole.(BEVA)''
Diagnosis
The definitive diagnosis of EGUS can only be made after visualisation of the stomach either ante mortem using a 2.5–3.0 m endoscope and utilising an established scoring system (Tables 1 and
2) or scoring system designed by investigators or at post mortem. However, if an endoscope of sufficient length is not available, clinical signs (rough hair coat, partial anorexia, mild weight loss, mild abdominal pain and poor performance) and response to treatment can be used in horses suspected of having EGUS. This is a conundrum because clinical signs are often vague and can lead to a subtle decrease performance. After ruling out other causes, alleviation of clinical signs and/or improvement in performance after treatment may suggest the diagnosis of EGUS (Anon 1999).
Other diagnostic methods include measuring urine and plasma sucrose concentration (sucrose permeability tests) (O’Conner et al. 2004; Hewetson et al. 2006). However, methods for measuring sucrose require sophisticated analysis equipment, which may not be practical for clinicians in the field.
(Nadeau 2009)
The presumptive diagnosis of EGUS is based typically on nonspecific clinical signs and response to therapy.(EGUC)
===Endoscopy===
===Endoscopy===
Endoscopic evaluation
Endoscopy (Fig 1) is currently the only reliable method for confirming a diagnosis of EGUS. Endoscopic equipment can be grouped into 2 categories: fibreoptic and video.
Flexible endoscopes: for mature equine gastric endoscopy, a minimum working length of 200 cm is required. However, a 280-300 cm long endoscope is required to perform duodenoscopy in mature individuals. A working length of 110 cm with an outer diameter of 10 mm (human gastroscope) is sufficient to reach the stomach of foals up to age 30-40 days.
Fibreoptic endoscopic equipment uses glass-fibre bundles to transmit light to the area to be viewed and transmit this image to an eyepiece. The image is magnified by a lens system within the eyepiece. This is important in alimentary endoscopy, since 150 W lamps used in most portable light sources provide poor illumination of a horse’s stomach. More powerful light sources are available (up to 300 W) but become larger and less portable as the lamp intensity increases. The quality of the fibreoptic instrument is determined largely by its image resolution, which is related directly to the number of optical fibres.
Videoendoscopic systems use glass-fibre bundles to transmit light, but use a charge-coupled device (CCD) chip to transmit the image. Generation of the light source (300 W) and processing of the CCD-generated electronic signal occurs in the endoscope’s processor.
Assessment of severity
The EGUS Council has adopted a lesion grading system that:
Is simple and straightforward
Can be applied to the squamous and glandular mucosal linings of the equine stomach
0Can be used by individual practitioners and researchers
Is similar to other grading systems used to characterise clinical severity of other body, systems (e.g. lameness,
neurological disorders, heart murmurs).
Lesion grading system
Grade 0 The epithelium is intact (Fig 2) and there is no appearance of hyperaemia (reddening) or hyperkeratosis (yellow appearance to the squamous mucosa)
Grade 1 The mucosa is intact, but there are areas of reddening or hyperkeratosis (squamous)
Grade 2 Small, single, or multifocal lesions
Grade 3 Large, single, or multifocal lesions or extensive superficial lesions
Grade4 Extensive lesions with areas of apparent deep ulceration.
Note that no mention of bleeding is made in assigning lesion grades, because bleeding does not determine lesion severity. Small superficial erosions (Fig 3) may bleed, whereas deep ulcers may not have active haemorrhage at the time of endoscopic examination.(EGUC)
The endoscopist may underestimate the n u m b e r of gastric ulcers and may not be able accurately to p redict the severity or depth of those ulcers present in the n o n g l a n d u l a r equine stomach. Furt h e r m o re, the endoscopist may miss glandular gastric ulcers. (Andrews 2002)
Squamous ulceration was scored by means of a grading scale from 0 to 3, according to Andrews and Nadeau (1999), as follows.
0 Intact mucosal epithelium (mild reddening and or mild hyperkeratosis),
1 Small single or small multifocal lesions,
2 Large single or large multifocal lesions or extensive superficial lesions, 3 Extensive (often coalescing) lesions with areas of apparent deep ulceration.(Prevelance)
A diagnosis can be made only by endoscopy (oesophagogastroscopy).
Oesophagogastroscopy may be performed at the facility where the horse is normally housed. The horse must be held off feed for 6-8 h before oesophagogastroscopy to allow time for the stomach to empty and permit visualisation of the mucosa. The procedure is usually performed approximately 5 min after i.v. sedation with xylazine (Rompun), 0.6-0.8 mgkg bwt. (Orsini)
Minimum endoscope length of two metres and 2.8-3.0 metre instruments are required for duodenoscopy A 3 metre endoscope allows visualization of stomach, pylorus and proximal duodenum (Sanchez) Shorter scopes permit investigation of gastric body and fundus only (Sanchez) Maximum external diameter of 9mm for neonates (Sanchez) Foals - lesions mainly in glandular epithelium Adults - margo plicatus and squamous epithelium
Performed under mild sedation in standing horse or foal (Sanchez)
Performed under mild sedation in standing horse or foal (Sanchez)
Duodenoscopy is most specific diagnostic method but is technically me chanllenegng than gastrocopy
Duodenoscopy is most specific diagnostic method but is technically me chanllenegng than gastrocopy
EGUS Lesion Scoring System publsihed based on consens by Equine Gastric Ulcer Council(2 in Sanchez)
EGUS Lesion Scoring System publsihed based on consens by Equine Gastric Ulcer Council(2 in Sanchez)
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Foals - lesions mainly in glandular epithelium
Foals - lesions mainly in glandular epithelium
Adults - margo plicatus and squamous epithelium
Adults - margo plicatus and squamous epithelium
Endoscopy is the primary method used for the identification of gastric ulceration in the live animal (Murray et al. 2001a) and numerous gross scoring systems combining lesion number and severity have been developed for classification purposes (Hammond et al. 1986; Johnson et al. 1994; Vatistas et al. 1994;Murray and Eichorn 1996; MacAllister et al. 1997; Anon 1999).
While these systems are useful for assessing the extent of disease and monitoring response to treatment, little work has been done to correlate gross observations with the histological picture. Lesions that appear alike grossly and receive similar numerical scores may have dissimilar histological appearances and underlying pathogeneses.(Martineau 2009)
===Radiography===
Abdominal radiography without contrast in foals with outflow obsturction typically rveeals very disticnt enlarged, gas-filled stomach. Liquid barium contrast will either have markedly delayed (with incomplete obstruction) oir no (complete onsbtruction) outflow. (Sanchez)
Abdominal radiography without contrast in foals with outflow obsturction typically rveeals very disticnt enlarged, gas-filled stomach. Liquid barium contrast will either have markedly delayed (with incomplete obstruction) oir no (complete onsbtruction) outflow. (Sanchez)
*Urine<ref>O'Connor, M.S, Steiner, J.M, Roussel, A.J, ''et al.'' (2004) Evaluation of urine sucrose concentration for detection of gastric ucleration in horses. ''Am J Vet Res'', 65:31-39. In: Sanchez, L.C (2010) 'Diseases Of The Stomach' in Reed, S.M, Bayly, W.M. and Sellon, D.C (2010) '''Equine Internal Medicine''' (Third Edition), Saunders, Chapter 15.</ref> and blood<ref>Hewetson, M, Cohen, N.D, Love, S, ''et al.'' (2006) Sucrose concentration in bood: a new method for assessment of gastric permeability in horses with gastric ulceration. ''J Vet Intern Med'', 20:388-394. In: Sanchez, L.C (2010) 'Diseases Of The Stomach' in Reed, S.M, Bayly, W.M. and Sellon, D.C (2010) '''Equine Internal Medicine''' (Third Edition), Saunders, Chapter 15.</ref> sucrose absorption as an assay of gastric mucosal permeability
*Urine<ref>O'Connor, M.S, Steiner, J.M, Roussel, A.J, ''et al.'' (2004) Evaluation of urine sucrose concentration for detection of gastric ucleration in horses. ''Am J Vet Res'', 65:31-39. In: Sanchez, L.C (2010) 'Diseases Of The Stomach' in Reed, S.M, Bayly, W.M. and Sellon, D.C (2010) '''Equine Internal Medicine''' (Third Edition), Saunders, Chapter 15.</ref> and blood<ref>Hewetson, M, Cohen, N.D, Love, S, ''et al.'' (2006) Sucrose concentration in bood: a new method for assessment of gastric permeability in horses with gastric ulceration. ''J Vet Intern Med'', 20:388-394. In: Sanchez, L.C (2010) 'Diseases Of The Stomach' in Reed, S.M, Bayly, W.M. and Sellon, D.C (2010) '''Equine Internal Medicine''' (Third Edition), Saunders, Chapter 15.</ref> sucrose absorption as an assay of gastric mucosal permeability
*Serum alpha1-antitrypsin which has been detected more frequently in foals with gastric ulceration<ref>Taharaguchi, S, Nagano, A, Okai, K, ''et al.'' (2007) Detection of an isoform of alpha(1)-antitrypsin in serum samples from foals with gastric ulcers. ''Vet Rec'', 161:338-342. In: Sanchez, L.C (2010) 'Diseases Of The Stomach' in Reed, S.M, Bayly, W.M. and Sellon, D.C (2010) '''Equine Internal Medicine''' (Third Edition), Saunders, Chapter 15.</ref>
*Serum alpha1-antitrypsin which has been detected more frequently in foals with gastric ulceration<ref>Taharaguchi, S, Nagano, A, Okai, K, ''et al.'' (2007) Detection of an isoform of alpha(1)-antitrypsin in serum samples from foals with gastric ulcers. ''Vet Rec'', 161:338-342. In: Sanchez, L.C (2010) 'Diseases Of The Stomach' in Reed, S.M, Bayly, W.M. and Sellon, D.C (2010) '''Equine Internal Medicine''' (Third Edition), Saunders, Chapter 15.</ref>
In a recent study, a faecal occult blood test was found to be helpful in diagnosis of EGUS (Pellegrini 2005). The positive predictive value of the faecal occult blood test (FOBT) in horses with EGUS was 90%; however, the negative predictive value was only 17%, which suggests that a horse with a positive FOBT islikely to have a gastric ulcer. In an attempt to improve the negative predictive value of the FOBT, investigators developed another test (SUCCEED Equine Fecal Blood Test)2 that utilises specific equine monoclonal antibodies to both albumin and haemoglobin in an easy to use kit (Carter and Pellegrini 2006; Pellegrini and Carter 2007). Recent reports showed an improved predictive value of a negative test (72%), but the predictive value of a positive test was slightly lower (77%). Thus, this new test may be helpful in diagnosing EGUS in horses, but should be used as part of a complete work-up. A false positive FOBT may result if a recent rectal examination, rectal biopsy or other rectal trauma has occurred or if the horse has a protein-losing enteropathy.
Furthermore, serum 1-antitrypsin was present in 44/47 foals with gastric ulcers compared to only 3/22 healthy foals (Taharaguchi et al. 2007). 1-antitrypsin may be released into serum from damaged gastric tissue, but more research is needed to validate this serum marker as a diagnostic test for EGUS.(Nadeau 2009)
===Pathology===
===Pathology===