INTESTINAL OBSTRUCTION AND ITS DIAGNOSIS IN DOGS
Dr. Pravesh Kumar Dwivedi, Dr. Sumit Kumar Patel and Dr. Vandana Sharma
College of veterinary science and animal husbandry, NDVSU, Jabalpur (M.P.) 482001
INTRODUCTION:-
Intestinal obstruction is defined as the partial or complete blockage of the flow of nutrients, secretions from the stomach into and through intestine resulting in disturbance in fluid balance, acid base status and serum electrolytes concentration due to hyper secretion and sequestration within the intestinal tract which is aggravated by vomiting and impaired oral intake of fluids and nutrients (Boag et al., 2005). Most incidences of foreign bodies are observed in stomach, jejunum and the lower incidences observed in the other parts of the lower digestive tract (Veeder and Taylor, 2009). Obstructing foreign bodies may be linear (Prasad et al., 2010) or discrete (Raghunath et al., 2016). Retrieval of various objects indicated that indiscriminate feeding habits of the dogs and diseases like pica which prone dogs to allotriophagia (Muhammad et al., 2014). Various other causes of intestinal obstruction reported to be are resultant of tumour, hypertrophy, gastric dilatation, volvulus, intussusception (Atray et al., 2012).
Diagnosis of this condition can be challenging and may include abdominal radiographs, ultrasonography, contrast studies, endoscopy and exploratory laparotomy. Abdominal ultrasonography and CT are highly effective and accurate in diagnosis of mechanical intestinal obstruction in dogs (Winter et al., 2017).
DIAGNOSIS
Signalment:-
Most dogs with linear foreign bodies are under 4 years of age (mean age is 4.5 years and the median age is 2 years). Playful young animals seem more prone to foreign body ingestion.
History:-
The presentation and clinical signs depend on the location, completeness, duration of the obstruction and vascular integrity of the involved segment. Occasionally the animal is seen swallowing the object. Profuse vomiting may be seen with complete proximal obstruction, vomiting with partial distal obstructions is usually intermittent. Defecation may be absent or decreased in frequency and stool is occasionally bloody. Diarrhoea is more common in animals with partial obstruction.
Physical examination:-
Classically, animals with high obstructions tend to be severely dehydrated. Abdominal palpation may identify a corrugated-feeling loop of bowel, an abnormal mass of bunched intestines, or may elicit pain. Linear foreign bodies may sometimes be visualized around the base of the tongue, but sedation/anesthesia may be required to visualize this area well enough to detect thin strings or thread. Abdominal pain is common if linear foreign bodies have caused bunching of the intestines. Abdominal auscultation may detect noise from peristaltic activity or silence associated with ileus.
DIAGNOSTIC IMAGING
Radiography:-
Abdominal radiography is frequently used to assess the abdomen in vomiting patients. Radiographic findings associated with a focal foreign body obstruction include intestinal dilatation, presence of ingesta oral to the obstruction and detection of foreign material within the intestinal tract (Tyrell and Beck, 2006). Diagnosis of intestinal distention may be aided by use of the ratio of maximum intestinal diameter to the height of the body of the fifth lumbar vertebra at its narrowest point. Values higher than 1.6 indicate the presence of distention, values higher than 2 indicate a high probability of obstruction.
Presence of luminal gas bubbles that are tapered at one or both ends is suggestive of a linear foreign body and the presence of three or more of these bubbles is always associated with a linear foreign body. The presence of free gas on preoperative radiographs is associated with 100% mortality. Animals with intussusceptions can have radiographic evidence of an intestinal mass effect in addition to intestinal distension however diagnosis of intussusception is not made consistently with plain film radiography (Burkitt et al., 2009).
Contrast radiography can aid in a radiographic diagnosis of an intestinal obstruction when plain film radiography does not lead to a diagnosis. Barium is the standard for evaluation of the stomach and small intestine using contrast radiography however barium should be used with caution if perforation is suspected or when surgery is inevitable as it is very irritating to the peritoneum. In cases of intestinal obstructions or perforations, it is advisable to use a nonionic iodinated contrast agent with low osmolality such as iohexol to achieve radiographic diagnosis. Barium sulfate enema can be used in patients suspected of having ileocolic or cecocolic intussusceptions. Radiographs will show distension of the intussuscipiens while the intussusceptum will appear lucent and there is often an abrupt end to the involved intestinal loop.
Ultrasonography:-
Ultrasonography is readily available in veterinary medicine and is useful for the diagnosis of intestinal obstructions. Ultrasonography can evaluate intestinal wall thickness (a normal small intestinal wall is 2 to 3 mm thick).
Computed tomography:-
Dogs are positioned in dorsal recumbency and routine abdominal-volume acquisition protocols are used. Transverse images are reconstructed with a 2 to 3mm slice thickness by use of bone and soft tissue algorithms. Data volumes are reformatted in sagittal and dorsal planes with a 2 to 3 mm slice thickness by use of a soft tissue algorithm. CT is often able to reveal the cause of obstruction and remains an important diagnostic tool when managing the cases. The requirement for profound sedation or anesthesia is a major limitation for using CT in small animal medicine. Image analysis for CT includes bowel diameter and ratios are measured at the time of data analysis and compared between dogs with and without obstruction (Winter et al., 2017).
Endoscopy :-
Endoscopy rarely diagnoses intestinal foreign bodies that are not detected radiographically or with ultrasound. This is because the scope seldom cannot be advanced beyond the descending duodenum. However, endoscopy is useful in diagnosing and removing gastric and high duodenal foreign bodies.
interrupted, simple continuous or connell suture pattern can be followed which will be discussed later.
REFERENCES
Atray, M., Raghunath, M., Singh, T. and Saini, N.S. (2012). Ultrasonographic diagnosis and surgical management of double intestinal intussusception in 3 dogs. The Canadian Veterinary Journal, 53(8): 860-862.
Boag, A.K., Coe, R.J., Martinez, T.A. and Hughes, D. (2005). Acid‐base and electrolyte abnormalities in dogs with gastrointestinal foreign bodies. Journal of Veterinary Internal Medicine, 19(6): 816-821.
Burkitt, J.M., Drobatz, K.J., Saunders, H.M. and Ishabau, R.J. (2009). Signalment, history and outcome of cats with gastrointestinal tract intussusception: 20 cases. Journal of the American Veterinary Medical Association, 234(6): 771-776.
Muhammad, S.T., Audu, S.W., Jahun, B.M., Lawal, M. and Adawa, D.A.Y. (2014). Diagnosis and management of sand impaction of the large intestine in an Alsatian puppy. Sokoto Journal of Veterinary Sciences, 12(2): 57-60.
Prasad, B.C., Rajesh, M.M. and Rao, C.M. (2010). Intestinal obstruction in a dog due to saree piece. Veterinary World, 3(9): 429-430.
Raghunath, M., Sagar, P.V., Sailaja, B. and Kumar, P.R. (2016). Surgical correction of intestinal obstruction in a german shepherd dog. Scholas Journal of Agriculture and Veterinary Sciences, 3(3): 187-189.
Veeder, C.L. and Taylor, D.K. (2009). Injury related to environmental enrichment in a dog (Canis familiaris): Gastric foreign body. Journal of the American Association for Laboratory Animal Science, 48(1): 76-78.
Winter, M.D., Barry, K.S., Johnson, M.D., Berry, C.R. and Case, J.B. (2017). Ultrasonographic and computed tomographic characterization and localization of suspected mechanical gastrointestinal obstruction in dogs. Journal of the American Veterinary Medical Association, 251(3): 315-321.
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