2012: Case report: Ileo-jejunal entrapment in a uterine mesometrium rent of a non-pregnant mare Case report: Ileo-jejunal entrapment in a uterine mesometrium rent of a non-pregnant mare Paula A. Schaffer,a Jennifer M. Sonis,b Jacobo S. Rodriguez,c Sushan Hana aDepartment of Microbiology, Immunology and Pathology; bDepartment of Clinical Sciences; cEquine Reproduction Laboratory; College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO Summary A ten-year-old, non-pregnant Arabian mare presented with acute uncontrollable abdominal pain. A diagnosis of small bowel compromise was made on clinical and trans-abdominal ultrasonographic examination. Euthanasia was elected by the owner and the necropsy examination revealed herniation and venous infarction of five meters of distal jejunum and the entire ileum within a 7.5 cm rent in the right mesometrium of the uterus. Small bowel entrapment in a mesometrial rent is rare in domestic animals with few case reports in the literature, but interestingly has been relatively well-characterized in primiparous and multiparous women. Entrapment in a mesometrial rent may be considered as a differential diagnosis for acute small bowel compromise and colic in non-pregnant and pregnant mares. Keywords: Broad ligament, entrapment, hernia, horse, small intestine Background Mesometrial rents have the potential to cause life-threatening small bowel entrapment in both humans and animals. This rare condition is well-documented in humans, but few published reports exist in the veterinary literature, and cases may be under-reported. Mesometrial herniation in women can have a promising surgical prognosis if treated early, and similar success has been historically reported in mares.1-3 In general, herniation and venous infarction of the small intestine is a common cause of acute abdominal pain and euthanasia in horses.4,5 Small intestinal hernias in horses most frequently occur in association with spontaneous, congenital, or traumatic rents in the abdominal mesentery, cecocolic fold, diaphragm,6 and within natural foramina including the gastroepiploic foramen, the inguinal ring of stallions, and the umbilicus of foals.7-10 Small bowel entrapment is rarely documented in rents within the lateral ligaments of the urinary bladder, mesodiverticulum and uterine mesometrium.4,8,9,11-13 The pathogenesis of rent formation in these unusual structures has not yet been determined and documentation of additional cases is necessary in order to improve our ability to make early diagnoses and to instigate successful surgical intervention. Case presentation A ten-year-old non-pregnant Arabian mare was presented to the Colorado State University Equine Critical Care Service with a four hour-history of acute abdominal pain. On presentation, the mare was tachycardic (70 beats/minute) and had a normal capillary refill time (< 2 seconds). Five liters of bright green watery reflux was obtained upon passing a nasogastric tube. On rectal palpation, loops of small intestine were moderately distended and there was mild gas distension of the large colon. Trans- abdominal ultrasound revealed non-motile, distended small intestine and large amounts of flocculent free abdominal fluid. Fluid obtained by abdominocentesis was serosanguinous with an elevated total protein level of 3.8 g/dL. A strangulating small intestinal lesion was suspected and exploratory laparotomy was recommended. The owner declined surgery and euthanasia was elected due to poor prognosis without surgical intervention. Outcome The mare was submitted for postmortem examination. At necropsy the abdominal cavity contained approximately ten L of yellow-tinged serosanguinous and fibrinous fluid. Approximately five meters of small intestine from the level of the distal jejunum to the ileo-cecal junction was herniated through a 7.5 cm diameter rent in the center of the right mesometrium of the uterus just cranial to the uterine artery (Figure 1). The incarcerated small intestine was dilated five cm in diameter. The serosal surface was diffusely mottled dark red and purple, and the wall was thickened one to two cm with transmural Clinical Theriogenology • Volume 3 Number 4 • December 2011Clinical Theriogenology • Volume 4 Number 1 • March 201255 Clinical Theriogenology • Volume 4 Number 1 • March 2012 hemorrha mucus, an mesentery mesentery hemorrha Figure 1. I herniated a was light p upper right Evalu normal gl there were firm fibro this site. glands, se the media septicemi Histop of the gut sloughed expanded segmental herniation fibrosis an mesotheli though a t ge and edema nd sloughed n y had a line of y. Incarcerate ge and edema In situ photogr and incarcerate pink, gas disten t quadrant (aste uation of the r istening seros e no lesions in ous adhesion t Additional gr evere and diff astinum and o a and shock. pathology of with ischemi and infiltrated by edema, bl l lymphoplasm n and necrosis nd consisted o ial reactivity. traumatic rent a. The intesti necrotic muco f demarcation ed mesentery a which exten raph of the post ed within a rent nded and sharp erisk). right mesomet sal membrane n the uterus a to the adjacen ross findings fuse pulmonar n the epicard incarcerated j ic necrosis ch d by colonies lood and scatt macytic enter s. The margin of normal fibr Lack of infla t occurring se inal lumen wa osa admixed w n that sharply was friable, d nded from the t-mortem exam t in the right m ly demarcated trium (Figure e, with no evi and ovaries. T nt mesocolon, included hem ry congestion ial surface, al jejunum and haracteristic o s of mixed bac tered inflamm ritis which ma ns of the mes rovascular me ammation or everal years in as filled with with finely gro delineated in discolored da e mesenteric b mination. Five mesometrium of from incarcera e 2) revealed t idence of hem The left meso , possibly ind morrhagic line n with petechi ll consistent w ileum confirm of entrapment cteria. The su matory cells. ay have occur ometrial rent esometrial str fibrosis is con n advance wit serosanguino ound feed ma ncarcerated m ark purple, and border to the m meters of dista f the uterus (ar ated bowel. Th that the rent w morrhage, infl ometrium had dicative of prio ear streaks in ial and ecchym with endotoxe med segmenta (Figure 3). T ubmucosa and Small intestin rred secondar lacked inflam roma covered nsistent with th termination ous fluid, clot aterial. The a mesentery from d markedly th mesenteric ro al jejunum and rrow). Non-her he right ovary i was smoothly lammation, or d a five x three or inflammati the cortex of motic hemorr emia and sugg al, transmural The mucosa w d tunica musc ne orad to the ry to adjacent mmation, hem d by smooth s a congenitall n of fibrosis a tted blood and associated m adjacent no hickened with oot. d ileum were rniated small b is visible in the y bordered by r fibroplasia, e x three cm f ion or trauma both adrenal rhages throug gestive of l venous infar was extensive cularis were e hernia had t small bowel morrhage, or erosa with m y formed rent and remodelin d ormal h bowel e and focal a at ghout rction ely ild t ng Clinical Theriogenology • Volume 3 Number 4 • December 2011Clinical Theriogenology • Volume 4 Number 1 • March 2012 56Clinical Theriogenology • Volume 4 Number 1 • March 2012 was also c hemorrha syndrome Figure 2. D of the rent and uterine Discussio The p be second from vario cystitis an rent forma parturient artery at m possibly r anomaly.1 The te had been b pregnancy this unrem hemorrha mesometr of the left the relatio lacked inf considered. T ge and coagu e). Dorsal view of were smooth w e arteries (arrow on pathogenesis o dary to pelvic ous causes of nd peritonitis) ation. Hemor t mares.14,15 H mid-gestation resulting in re 1,2,15 en-year-old n bred by live c y with unassis markable heal ge of the mes rial defect and t mesometrium on of this lesio flammation an The zona glom ulative necrosi f the uterus. A with no hemorr ws) were gross of mesometria trauma such f abdominal in ) which may r rrhage from u Hematomas ca or parturition ent formation. non-pregnant m cover as a thre sted parturitio lth history, it i sometrium du d permanent r m and mesoco on to the mes nd fibrosis, a merulosa of th is, consistent 7.5 cm rent w rhage or fibros sly normal. al rent format as may be ass nflammation result in tears uterine or ova an form in the n. Improper h .15 Abdomina mare in this c ee- and four-y on and no hist is possible th uring pregnanc rent formation olon suggests ometrial rent congenital de he adrenal cor with endotox was present in th sis. The uterine tion in the ma sociated with (i.e. perforati in the ligame arian vessels i e mesometriu healing may r al rents in gen case report ha year old, and tory of dystoc at the mare m cy and partur n in the right s a prior histor and prior pre efect is also c rtex was exte xic shock (Wa he right mesom e body (arrowh are has not be h dystocia, pre ing or necrotiz ent and subse s a well-docu um due to rup result in focal neral may also ad no previous successfully cia or post-pa may have had rition, which m mesometrium ry of at least egnancies is p considered lik ensively disrup aterhouse-Fri metrium (asteri head), uterine h een determine evious abdom zing enteritis equent healing umented comp pture of the m l necrosis of t o be a spontan s history of co produced a fo artum complic subclinical p may have resu m. Indeed, the focal pelvic s purely specula kely in this ca pted by derichsen isk). The marg horns (open arr ed. Defects m minal surgery, , colitis, metr g with perman plication in p iddle uterine the mesometr neous congen olic. The ma foal from each cations. Desp elvic trauma ulted in a e gross adhes serositis, thou ative. As the se. gins rows) may or ritis, nent ost- rium, nital are h pite or sion ugh rent Clinical Theriogenology • Volume 3 Number 4 • December 2011Clinical Theriogenology • Volume 4 Number 1 • March 201257 Clinical Theriogenology • Volume 4 Number 1 • March 2012 T literature colitis of 3 explorator through w made to th intestine a performed complicat with acute jejunum w intestine w defect wa recovered Figure 3. P ischemic n extensive h arterioles ( To the animal sp rare, but w and 4-7% history of occur.17 D tomograph intestine, Two case repo published in 36 hours dura ry standing la what was presu he mare’s prio appeared viab d. The mare r tion. In the 1 e colic of six were herniated was successfu s not closed o d from colic su Photomicrogra necrosis of the i hemorrhage an (arrow). H&E, e authors’ kno ecies or in co well-described of all interna f uterine surge Diagnosis of b hy scan, and surgical resec orts of mares w 1972 and 198 ation. The ma aparotomy.2 A umed to be a or breeding h ble and no res recovered afte 980 report, a hours duratio d in a rent in t ully reduced a or ablated in t urgery and de aph of incarcera intestinal wall. nd edema of the Bar 500 µm. owledge, no c ompanion anim d in women, i al hernias.16-22 ery, salpingiti bowel herniat surgical corre ction and ana with small int 80. In the 197 are had sever At surgery, th congenital de history and the ection was re er surgery an four-year-old on.3 A ventral the right mes and resection this case, and elivered a nor ated jejunum. . The mucosa w e submucosa, a comparable re mals. Interes in which it ac 2 In women m is, or endome tion in a meso ection can be stomosis if ne testinal hernia 72 report, a th e abdominal p he entire jejun efect in the le e rent could n equired. Abla d was subseq d Belgian mar l midline celi ometrium. S and anastomo gross feature rmal foal three There was tran was sloughed w and marked ven eports are ava tingly, small ccounts for < mesometrial r triosis, thoug ometrial rent performed by ecessary, and ation in a mes hree-year-old pain on rectal num and most eft mesometriu not be grossly ation of the le quently used f re in the eight iotomy was p imilar to the osis was not n es of the rent e months late nsmural venou with moderate nous dilation (a ailable regard bowel hernia 0.1% of all c rents are assoc gh congenital is based on cl y laparoscopi d ablation of th sometrial rent pony mare p l palpation an t of the ileum um, though n y visualized. T eft broad ligam for breeding w th month of g erformed and first case, the necessary. Th were not prov er. us infarction, he inflammation asterisks) and ding this cond ation in a mes auses of intes ciated with m rents are also linical signs a ic reduction o he mesometri t are in the resented for a nd underwent m had herniate no reference w The herniated ment was without gestation pres d five meters o e herniated he mesometri vided. The m emorrhage, and (arrowhead) a congestion of dition in other sometrial rent stinal obstruct multiparity or o thought to and computer of herniated ial defect to acute ed was d ented of ial mare d and r large t is tion a rized Clinical Theriogenology • Volume 3 Number 4 • December 2011Clinical Theriogenology • Volume 4 Number 1 • March 2012 58Clinical Theriogenology • Volume 4 Number 1 • March 2012 prevent recurrence. Ablation is achieved either by suturing the defect closed or by surgically incising the mesometrium to connect the defect with the lateral mesometrial fold. In humans, mesometrium defects are classified into three types based on location in reference to the round ligament.23 Small intestinal herniation in a mesometrial rent should be considered as a differential diagnosis in maiden mares and mares that have previously foaled or are currently pregnant which present with signs of acute abdominal pain and small bowel entrapment. The time elapsed between presentation of initial signs and surgical intervention, as well as extent of small bowel incarceration likely determine the outcome, though at least some surgical cases had long-term favorable outcomes.2,3 Learning points • Herniation of intestine through rents in the mesometrium is an important differential for acute colic in maiden mares and mares that have previously foaled or are currently pregnant. • Mesometrial rents may occur congenitally in the mare, and post-parturient trauma or abdominal inflammation may also be a risk factor, as is often the case in women. • Meticulous examination of the mesometrium should be considered in post-parturient mares to identify possible mesometrial lesions that could result in future rent formation. • Intestinal herniation through a mesometrial rent should be a differential diagnosis for a mare presenting with acute colic even if the previous reproductive history is unremarkable. References 1. Arnold CE, Payne M, Thompson JA, et al: Periparturient hemorrhage in mares: 73 cases (1998-2005). J Am Vet Med Assoc 2008;232:1345-1351. 2. Lamothe P, Giguere G, Marcoux M: Hernia of the broad ligament of the uterus in a mare. Mod Vet Pract 1972;53:49. 3. Becht JL, McIlwraith CW: Jejunal displacement through the mesometrium in a pregnant mare. J Am Vet Med Assoc 1980;177:436. 4. Tennant B, Wheat, JD, Meagher, DM: Observations on the causes and incidence of acute intestinal obstruction in the horse. Proc Annu conv Am Assoc Equine Pract 1975. p. 426-438. 5. Wheat JD: Causes of colic and types requiring surgical intervention. J S Afr Vet Med Assoc 1975;46:95-98. 6. Santschi EM, Juzwiak JS, Moll HD, et al: Diaphragmatic hernia repair in three young horses. Vet Surg 1997;26:242- 245. 7. Archer DC, Proudman CJ, Pinchbeck G, et al: Entrapment of the small intestine in the epiploic foramen in horses: a retrospective analysis of 71 cases recorded between 1991 and 2001. Vet Rec 2004;155:793-797. 8. Gayle JM, Blikslager AT, Bowman KF: Mesenteric rents as a source of small intestinal strangulation in horses: 15 cases (1990-1997). J Am Vet Med Assoc 2000;216:1446-1449. 9. Gayle JM, Macharg MA, Smallwood JE: Strangulating obstruction caused by intestinal herniation through the proximal aspect of the cecocolic fold in 9 horses. Vet Surg 2001;30:40-43. 10. Voermans M, Butler CM, van der Velden MA, et al: Incarcerated umbilical hernia in the horse: a case with a review of the literature. Tijdschr Diergeneeskd 2004;129:142-149. 11. Freeman DE, Koch DB, Boles CL: Mesodiverticular bands as a cause of small intestinal strangulation and volvulus in the horse. J Am Vet Med Assoc 1979;175:1089-1094. 12. Hawkins JF, Schumacher JS, McClure SR, et al: Small intestinal incarceration through the lateral ligament of the urinary bladder in a horse. J Am Vet Med Assoc 1993;202:89-90. 13. Jenei TM, Garcia-Lopez JM, Provost PJ, et al: Surgical management of small intestinal incarceration through the gastrosplenic ligament: 14 cases (1994-2006). J Am Vet Med Assoc 2007;231:1221-1224. 14. LeBlanc MM: Common peripartum problems in the mare. Equine Vet Sci 2008;28:709-715. 15. Ueno T, Nambo Y, Tajima Y, et al: Pathology of lethal peripartum broad ligament haematoma in 31 Thoroughbred mares. Equine Vet J 2010;42:529-533. 16. Fafet P, Souiri M, Ould Said H, et al: Internal hernia of the small intestine through a breach of the broad ligament, apropos of a case. Review of the literature. J Chir (Paris) 1995;132:314-317. 17. Guillem P, Cordonnier C, Bounoua F, et al: Small bowel incarceration in a broad ligament defect. Surg Endosc 2003;17:161-162. 18. Haku T, Daidouji K, Kawamura H, et al: Internal herniation through a defect of the broad ligament of the uterus. Abdom Imaging 2004;29:161-163. 19. Hiraiwa K, Morozumi K, Miyazaki H, et al: Strangulated hernia through a defect of the broad ligament and mobile cecum: a case report. World J Gastroenterol 2006;12:1479-1480. 20. Ishihara H, Terahara M, Kigawa J, et al: Strangulated herniation through a defect of the broad ligament of the uterus. Gynecol Obstet Invest 1993;35:187-189. Clinical Theriogenology • Volume 3 Number 4 • December 2011Clinical Theriogenology • Volume 4 Number 1 • March 201259 Clinical Theriogenology • Volume 4 Number 1 • March 2012 21. Natalini G, Trancanelli V, Gerli P, et al: Internal hernia through an orifice of the broad ligament of the uterus. Minerva Chir 1980;35:1359-1362. 22. Nozoe T, Anai H: Incarceration of small bowel herniation through a defect of the broad ligament of the uterus: report of a case. Surg Today 2002;32:834-835. 23. Cilley R, Poterack K, Lemmer J, et al: Defects of the broad ligament of the uterus. Am J Gastroenterol 1986;81:389- 391. 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