CC BY
55
Marcin Jankowski, Krzysztof Kubiak, Jolanta Spuzak, Kamila Glinska-Suchocka, Jozef Nicpon, Maciej Grzegory, Igor Maksymovych*©
Department of Internal Diseases with Clinic for Horses, Dogs and Cats, Faculty of Veterinary Medicine, University of Environmental and Life Sciences, pl. Grunwaldzki
47, 50-366 Wroclaw, Poland *Department of Clinical Diagnostics, Lviv National University of Veterinary Medicine and Biotechnology, ul. Pekarska 50, 79010 Lviv, Ukraine
DIAGNOSIS OF MEGAESOPHAGUS IN DOGS AND CATS
Key words: megaesophagus, dog, cat, X-ray examination, esophagoscopy
Introduction
Megaesophagus (megaesophagus, dilatation s. ectasis oesophagi) is a disease in which the esophagus lumen is dilated due to motoric activity disturbances leading to accumulation of food in its lumen (Morgan 2003, Hall et al. 2005, Lopuszynski et al.2007).
On account of causes of this disease three kinds of megaesophagus are distinguished:
1) congenital idiopathic megaesophagus (megaesophagus congenitalis idiopathicum) - the cause is unknown,
2) acquired idiopathic megaesophagus (megaesophagus acquisitus idiopathicum) - the cause is unknown,
3) acquired secondary megaesophagus (megaesophagus acquisitus) - the cause may be identified (Simpson 1994, Guilford 1996, Washabau 2005).
There is also a clinical classification according to location of the esophagus dilation which may affect the whole organ or its part.
Megaesophagus incidence rate is quite low. It is most often found in dogs, less frequently in cats and the least frequently in horses (Broekman and Kuiper 2002, Morgan 2003, Van Geffer et al. 2006, Lopuszynski et al. 2007).
The etiology of the congenital idiopathic megaesophagus and acquired idiopathic megaesophagus is unknown. It is suspected that the reasons for the congenital idiopathic megaesophagus include: disturbances of the esophagus innervation maturing, paralysis of the muscles walls and abnormal functioning of the inferior sphincter of the esophagus (Koper et al. 1974, Simpson 1994, Guilford 1996, Holland et al. 2002, Morgan 2003, Washabau 2005). This kind of the esophagus is found in the following breeds of dogs: Miniature Schnautzer, German Shepherd, Dalmatian, Great Dane, Irish Setter, Labrador and Shar-Pei, and among cats -Siamese (Cox et al.1980, Simpson 1994, Guilford 19946, Morgan 2003, Hall et al. 2005, Washabau 2005).
The acquired secondary megaesophagus has a multi-factor etiology but it is very difficult to determine what triggered the disease. The reasons for this kind of megaesophagus include:
- neuromuscular diseases - e.g.: bilateral vagal nerve damage, botulism, dysautonomia, polymyopathy/polymyositis, tetanus, myasthenia (local and general),
© Marcin Jankowski, Krzysztof Kubiak, Jolanta Spuzak, Kamila Glinska-Suchocka, Jozef Nicpon, Maciej Grzegory, Igor Maksymovych, 2009
209
- heavy metals toxicity - e.g.: lead, thallium,
- diseases of the esophagus - e.g.: acute esophagitis, foreign bodies in the esophagus, esophagostenosis, gastro-esophageal reflux, hiatus hernia,
- endocrinological diseases - e.g.: adrenocortal insufficiency, hypothyroidism, pituitary dwarfism,
- other diseases - e.g.: systemic lupus erythematosus, canine distemper virus, the central nervous system injuries, mediastinitis, glycogenosis, bronchoesophageal fistula, abnormally running blood vessels (Stachell and McLeod 1984, Satchell 1990, simpson 1994, Guilford 1996, Morgan 2003, Hall et al. 2005, Washabau 2005, Wray and Sparkes 2006, Larcher 2006, Lopuszynski et al. 2007).
There is no predisposition to breed, sex and age in this kind of megaesophagus. Only an increased incidence rate is observed in German Shepherds, Golden Retrievers and Irish Setters.
The clinical signs of megaesophagus depend on the diameter and extensiveness of dilation, the disease duration, the primary cause underlying megaesophagus and diseases complicating megaesophagus. The most frequently observed clinical signs include: regurgitation of food, hypersalivation, dysphagia, "empty" swallowing, unpleasant odour from the mouth (fetor ex ore), the body weight loss. In the case of aspiration pneumonia, which is the most common complication of megaesophagus, the following signs may be observed: moist cough, dyspnea, tachypnea and moist rales (Simpson 1994, Guilford 1996, Morgan 2003, Boria et al. 2003, Washabau 2005, Lopuszynski et al. 2007).
The diagnosis of megaesophagus should be based on: the history, clinical examination, laboratory blood and urine tests, an X-ray examination and an endoscopic examination of the esophagus (esophagoscope) (Guilford 1996, Morgan 2003).
In the differential diagnosis the following factors should be taken into account: all causes of the esophagus obstruction, acute esophagitis, the esophagus diverticula and esophagstenosis (Guilford 1996, Morgan 2003, Washabau 2005).
Task, the aim of the article The aim of the study was to present own experience in diagnostics of megaesophagus in dogs and cats.
Material and methods The study entailed 12 animals referred to the Endoscopy Laboratory of the Department of Internal Diseases with Clinic for Horses, Dogs and Cats for endoscopy of the anterior part of the digestive tract (esophagoscopy, gastroscopy, duodenoscopy).
Each dog was subject to the history, clinical examination, laboratory blood tests (hematological and biochemical), X-ray examination and endoscopy of the anterior part of the digestive tract.
Panendoscopy was performed after appropriate dietary preparation of the patient which consisted in 24h fasting and 6h break in administration of liquids immediately before the examination, in general anesthesia according to the following pattern: Dogs
- premedication: xylasine (1-2 mg/kg b.w.) with atropine (0.05 mg/kg b.w.), administered in one intramuscular injection (i.m.),
210
- general anesthesia: thiopentale ( initial dose 5 mg/kg b.w. , and next according to the effect ), intravenously (i.v.),
- local anesthesia of the pharynx and larynx area: 2% lidocaine Cats
- xylasine (1-2 mg/kg b.w.) and ketamine (10-20 mg/kg b.w.) administered in one intramuscular injection (i.m.),
- local anesthesia of the pharynx and larynx area: 2% lidocaine.
The endoscopy was performed using Olympus GIF XQ 20 fiberscope (working length - 100 cm, diameter - 9.8 mm).
Result of research
In the years 2002-2008 megaesophagus was diagnosed in 12 animals (11 dogs and 1 cat) which were referred to the Endoscopy Laboratory of the Department of Internal Diseases with Clinic for Horses, Dogs and Cats, which constituted 3.9% of cases in which the endoscopic examination of the anterior part of the digestive tract had been performed. A relatively low megaesophagus incidence rate in dogs and cats is confirmed by other authors (Clifford et al. 1971, Harvey et al. 1974, Hoening et al. 1990, Maddison and Allen 1990, Guilford 1996). Megaesophagus was diagnosed in the following breeds: Miniature Schnautzer, Miniature Pincher, Great Dane, Dalmatian, German Shepherd (5 dogs), Dachshund, Irish Setter, Medium Poodle and among cats - in the European breed. In 8 (66.6%) cases megaesophagus was diagnosed in adult animals, and in 4 (33.3%) cases - in young animals.
The history and clinical examination of the animals with megaesophagus revealed the following signs : regurgitation after meals - 11 (91.6%) cases, vomit - 4 (33.3%) cases, hypersalivation - 4 (33.3%) cases, dysphagia - 2 (16.6%) cases, unpleasant odour from the mouth (fetor ex ore ) - 5 ( 41.6% ) cases, " gurgling " - 1 (8.3%) case, the body weight loss - 4 (33.3%) cases, anorexia - 1 (8.35) case, slightly pale mucosa - 1 (8.3%) case, unthriftiness - 3 (25%) cases, dehydration - 2 (16.6%), purulent nasal discharge - 1 (8.3%) case, moist cough - 3 (25%) cases, dyspnea - 3 (25%) cases, the elevated body temperature - 2 (16.6%) cases and moist rales - 3 (25%) cases. The most frequent sign observed in the animals was regurgitation (false vomit). In 3 cases the clinical signs indicated aspiration pneumonia, a complication of megaesophagus. The similar clinical signs in the animals with megaespohagus were reported by other authors (Guilford 1996, Morgan 2003, Boria et al. 2003, Washabau 2005, Lopuszynski et al. 2007).
The hematological examination showed in 4 cases an increased number of leucocytes, in 1 case- a decreased number of erythrocytes, in 1 case - a decreased hemoglobin concentration, in 1 case - a decreased hematocrit number and in 2 cases - an increased hematocrit number. The biochemical test results were within the physiological norm.
The X-ray examination or contrast X-ray examination showed in all the animals: dilation of the esophagus lumen, the ventrad trachea deflection, gas and contrast chyme in the esophagus, in 4 cases the radiological evaluation of the base of the heart was difficult, in 3 cases the signs of aspiration pneumonia were recognized. The above radiological changes in the animals with megaesophagus are confirmed by other authors (Guilford 1996, Morgan 2003, Washabau 2005, Lopuszynski et al 2007).
The esophagoscopy carried out in the animals revealed the following changes: dilation of the esophagus lumen of the cervical or thoracic or both segments - 12
211
cases, erythema and swelling of the esophagus mucosa - 10 cases, liquid, grey-cream chyme - 7 cases, diphtheroid deposits on the esophagus mucosa - 2 cases, mucosa fragility - 3 cases.
It should be emphasized that the evaluation of the esophagus lumen size in esophagoscopy must always be considered with the X-ray examination and/or contrast X-ray examination results, since during endoscopy the esophagus wall is always subject to flabbiness which results from anesthesia (Guilford 1996, Morgan 2003, Washabau 2005).
On the basis of the history, the clinical examination, laboratory blood tests, X-ray examination and esophagoscopic examination the idiopathic megaesophagus was diagnosed in 9 (75%) animals including 2 dogs with most probably - congenital megaesophagus; in 3 (25% ) cases acquired megaesophagus was suspected the reason for which was an abnormal blood vessels network.
Conclusion
Based on the conducted research it was found that the clinical signs of megaesophagus in dogs and cats are non-specific and may indicate other diseases of the esophagus, as e.g. the esophagus diverticula, esophagostenosis. Moreover, it was found that the most specific complementary examination allowing evaluation of the esophagus lumen size is a X-ray examination. However, only the endoscopic examination makes evaluation of the esophagus mucosa pathological changes possible.
Reference
1. Boria P.A., Webster C.R.L., Berg J.: Esophageal achalasia and secondary megaesophagus in a dog. Can. Vet. J. 2003, 44, 232 - 234.
2. Broekman L.E., Kuiper D.: Megaesophagus in the horse. A short review of the literature and 18 own cases. Vet. Q. 2002, 24, 199 - 202.
3. Clifford D.H., Soifer F.K., Wilson C.F., Waddell E.D., Guilloud G.L.: Congenital achalasia of the esophagus in four cats of common ancestry. J. Am. Vet. Med. Assoc. 1971,158, 1554 - 1560.
4. Cox V.S., Wallace L.J., Anderson V.E., Rushmer R.A.: Hereditary esophageal dysfunction in the miniature schnauzer. Am. J. Vet. Res. 1980, 41, 326 - 330.
5. GUILFORD G.W., WILLIAMS D.A., CENTER S.A., MEYER D.J., STROMBECK DR.: STROMBECK'S SMALL ANIMAL GASTROENTEROLOGY, 1996, W. B. SAUNDERS, PHILADELPHIA.
6. Hall E.J., Murphy K.F., Darke P.G.G.: Choroby wewn^trzne psow. 2005, SIMA, Warszawa.
7. Harvey C.E., O'Brien J.A., Durie V.R., Miller D.J., Veenema R.: Megaesophagus in the dog: a clinical survey of 79 cases. J. Am. Vet. Med. Assoc. 1974,165, 443 - 446.
8. Hoenig M., Mahaffey M.B., Parnell P.G., Styles M.E.: Megaesophagus in two cats. J. Am. Vet. Med. Assoc. 1990, 196, 763 - 765.
9. Holland C.T., Satchell P.M., Farrow B.R.: Selective vagal afferent dysfunction in dogs with congenital idiopatic megaesophagus. Auton. Neurosci. 2002, 99, 18 - 23.
10. Koper S., Welento J., Flieger S.: Badania kliniczne i neuroanatomiczne nad achalazja u psa. Medycyna Wet. 1974, 30, 231 - 234.
212
11. Larcher T., Abadie J., Roux F.A., Deschamps J.Y., Wyers M.: Persistent left cranial vena cava causing oesophageal obstruction and consequent megaoesophagus in a dog. J. Comp. Path. 2006, 135, 150 - 152.
12. Lopuszynski W., Nozdyn-Plotnicki Z., Struzik A., Debiak P., Kutrzuba J.: Przefyk olbrzymi u psów. Magazyn Wet. 2007, 16, 46 - 50.
13. Maddison J.E., Allan G.S.: Megaesophagus attributable to lead toxicosis in a cat. J. Am. Vet. Med. Assoc. 1990, 197, 1357 - 1358.
14. Morgan R.V.: Handbook of small animal practice. W.B Saunders, 2003, Philadelphia.
15. Simpson J.: Management of megaoesophagus in the dog. In Pract. 1994, 16, 14 - 16.
16. Satchell P.M.: The neuropathic oesophagus. A radiographic and manometric study on the evolution of megaoesophagus in dogs with diveloping axonal neuropathy. Res. Vet. Sci. 1990, 48, 249 - 255.
17. Stachell P.M., McLeod J.G.: Abnormalities of oesophageal mechanoreceptors in canine acrylamide neuropathy. J. Neurol. Neurosurg. Psychiatry. 1984, 47, 692 - 698.
18. Van Geffer C., Saunders J.H., Vandevelde B., Van Ham L., Hoybergs Y., Daminet S.: Idiopatic megaoesophagus ind intussusception in cat. J. Small Anim. Pract. 2006, 47, 471 - 475.
19. Washabau R.J.: Gastrointestinal Motility Disorders of Dogs and Cats. Proceedings of the 30th World Congress of WSAVA, 11 - 14 May 2005 Mexico.
20. Wray J.D., Sparkes A.H.: Use of radiographic measurements in distinguishing myasthenia gravis from other causes of canine megaoesophagus. J. Small Anim. Pract. 2006, 47, 256 - 263.
Summary
The aim of the study was to present own experience concerning possibilities of diagnosing megaesophagus in dogs and cats. The study entailed 12 animals from among dogs and cats referred to the Endoscopy Laboratory. Each dog was subject to the history, clinical examination, laboratory blood tests (hematological and biochemical), an X-ray examination and/or contrast X-ray examination and endoscopy of the anterior segment of the digestive tract. Based on the conducted research it was found that the clinical signs of megaesophagus in dogs and cats are non-specific and may indicate other diseases of the esophagus, as e.g. the esophagus diverticuli, esophagostenosis. Moreover, it was found that the most specific complementary examination allowing evaluation of the esophagus lumen size is a X-ray examination. However, only the endoscopic examination makes evaluation of the esophagus mucosa possible.
Стаття надшшла до редакцИ 25.09.2009
213
