Idiopathic muscular hypertrophy of the equine small intestine: 11 cases (1980-1991).
Abstract: The medical records of 11 horses with idiopathic muscular hypertrophy (MH) of the small intestine were reviewed to determine the clinical and pathological features of the disease. The median age of affected horses was 10.0 years (range 5-18 years). No breed or sex predisposition was apparent. Ten horses (91%) had chronic (23 days to 2.4 years) signs of mild, intermittent colic, and 1 horse had signs of severe colic of only 3 days' duration. Partial anorexia and chronic weight loss of variable duration (1-6 months) were prominent historical findings in 5 (45%) horses. Diagnostic tests, with the exception of exploratory caeliotomy, were ineffective for definitive diagnosis of intestinal MH as a cause of colic. In 2 horses, however, a thickened, rigid ileum was detected by palpation per rectum, and in 5 horses, multiple loops of distended small intestine were detected by palpation per rectum. Hypertrophy of both the circular and longitudinal layers of muscularis was determined as the cause of intestinal thickening in all horses. Muscular hypertrophy of the ileum was present in 9 (82%) horses. Two horses (18%) had MH of a section of jejunum only, and 4 (36%) horses had MH of the ileum in combination with MH of other sections of small intestine. Two (18%) horses had MH of the entire small intestine. In 9 (82%) horses, intestinal MH resulted in narrowing of the luminal diameter at the site of MH. Small diverticula were present on the mesenteric border of the hypertrophied ileum of 5 (45%) horses. Five linear (up to 150-cm) diverticula were present in the hypertrophied jejunum of 1 (9%) horse. Haemomelasma ilei was present on the antimesenteric serosal surface of affected intestine of 8 (73%) horses. Full-thickness rupture of the ileum with subsequent diffuse, septic peritonitis occurred in 3 (27%) horses.
Publication Date: 1992-09-01 PubMed ID: 1396511DOI: 10.1111/j.2042-3306.1992.tb02858.xGoogle Scholar: Lookup
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Summary
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The study examines the clinical and pathological characteristics of 11 horses with unrecognized muscular hypertrophy (MH) of the small intestine. The research revealed a majority of horses with chronic signs of light, inconsistent colic and partial loss of appetite, with diagnostic tests proving ineffective save for exploratory abdominal surgery. The study also uncovered possible detection of a thickened, inflexible small intestine through rectum palpation.
Review of Medical Records and Findings
- The medical records of 11 horses exhibiting idiopathic muscular hypertrophy (MH) of the small intestine were analyzed to identify the clinical and pathological traits of the disease.
- Investigation revealed that the affected horses had a median age of 10 years, spanning from 5 to 18 years, and displayed no clear inclination concerning breed or gender.
Symptoms in Horses
- Chronic indications of mild, non-constant colic, were found in 91% of horses and had durations varying between 23 days to 2.4 years. One horse however exhibited severe colic symptoms for a duration of just 3 days.
- Partial consumption of food and progressive loss of weight over 1-6 months were significant historical findings in 45% of the horses.
Diagnostic Tests and Results
- Standard diagnostic methods, save for exploratory caeliotomy (abdominal surgery), were ineffective in conclusively diagnosing intestinal MH as a cause of colic.
- Nonetheless, by physically examining the rectum (per rectum palpation), a thickened, stiff ileum (part of the small intestine) was identified in two horses while multiple expanded loops of the small intestine were found in five horses.
Pathological Features
- All the horses showed intestinal thickening due to hypertrophy of both the circular and longitudinal muscular layers.
- Out of all the cases, 82% of horses had muscular hypertrophy in the ileum, 18% in a section of the jejunum (part of the small intestine), and 36% exhibited MH of both the ileum and other sections of the small intestine. 18% of these horses had muscular hypertrophy all over the small intestine.
Consequences of Intestinal Muscular Hypertrophy
- Intestinal MH in 82% of the horses resulted in a reduction of the luminal diameter at the site of MH.
- Small diverticula (bulging, pouch-like structures) were found in 45% of horses on the mesenteric border of the hypertrophied ileum while linear ones were noticed in the hypertrophied jejunum of a single horse.
- Haemomelasma ilei (a type of bruising) was present on the outer surface of the affected intestine of 73% of the horses.
- In three horses (27%), a complete rupture of the ileum occurred, leading to generalized septic peritonitis (infection in the abdomen).
Cite This Article
APA
Chaffin MK, Fuenteabla IC, Schumacher J, Welch RD, Edwards JF.
(1992).
Idiopathic muscular hypertrophy of the equine small intestine: 11 cases (1980-1991).
Equine Vet J, 24(5), 372-378.
https://doi.org/10.1111/j.2042-3306.1992.tb02858.x Publication
Researcher Affiliations
- Department of Large Animal Medicine, College of Veterinary Medicine, Texas A&M University, College Station 77843-4475.
MeSH Terms
- Animals
- Breeding
- Colic / diagnosis
- Colic / pathology
- Colic / surgery
- Colic / veterinary
- Female
- Horse Diseases / diagnosis
- Horse Diseases / pathology
- Horse Diseases / surgery
- Horses
- Hypertrophy
- Intestinal Diseases / diagnosis
- Intestinal Diseases / pathology
- Intestinal Diseases / surgery
- Intestinal Diseases / veterinary
- Intestine, Small / pathology
- Male
- Muscle, Smooth / pathology
- Treatment Outcome
Citations
This article has been cited 9 times.- Willette J, Guinn A, Munsterman A. Primary Jejunal Impactions Resolved via Exploratory Celiotomy in Six Horses: 2017-2023. Animals (Basel) 2025 Aug 12;15(16).
- Jang H, Kim SW, Lee JW, Kim M, Jung DI. Idiopathic Intestinal Smooth Muscle Hyperplasia in a French Bulldog: Clinical, Imaging, Capsule Endoscopy, and Histopathological Findings. Animals (Basel) 2025 Apr 23;15(9).
- Onzere CK, Hulbert M, Sears KP, Williams LBA, Fry LM. Tulathromycin and Diclazuril Lack Efficacy against Theileria haneyi, but Tulathromycin Is Not Associated with Adverse Clinical Effects in Six Treated Adult Horses. Pathogens 2023 Mar 14;12(3).
- Leventhal HR, Hassebroek AM, Carvallo F, McKenzie HC. Small intestinal pseudodiverticulosis in a pony mare. J Vet Diagn Invest 2021 Nov;33(6):1123-1127.
- Pavone S, Stazi M, Cambiotti V, Castro V, Gobbi M, Zema J, Filippini G. Cases of intestinal smooth muscle hypertrophy/hyperplasia in pigeon and chickens. J Vet Med Sci 2019 Oct 10;81(9):1351-1354.
- Mahne AT, Janse van Rensburg D, Hewetson M. Ileal hypertrophy and associated true diverticulum as a cause of colic in a horse. J S Afr Vet Assoc 2017 May 26;88(0):e1-e5.
- Davis HA, Munsterman A. Ileal impaction and jejunal enterotomy in a 4-month-old Arabian filly. Can Vet J 2012 Jan;53(1):71-4.
- Wefel S, Mendez-Angulo JL, Ernst NS. Small intestinal strangulation caused by a mesodiverticular band and diverticulum on the mesenteric border of the small intestine in a horse. Can Vet J 2011 Aug;52(8):884-7.
- Diana A, Pietra M, Guglielmini C, Boari A, Bettini G, Cipone M. Ultrasonographic and pathologic features of intestinal smooth muscle hypertrophy in four cats. Vet Radiol Ultrasound 2003 Sep-Oct;44(5):566-9.
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