Idiopathic non dilatative muscular hypertrophy of the equine duodenum

Abstract

Idiopathic non dilatative muscular hypertrophy of the equine duodenum Duodenal diseases are rare conditions in equine gastroenterology. The authors report about three cases of idiopathic muscular hypertrophy of the duodenum which finally caused an intestinal rupture and resulted in septical peritonitis. Clinical signs and presurgical evaluation revealed no evidence for a chronic small intestinal disease such as recurrent colic or weight loss. The three horses were presented with acute onset of abdominal pain. The diagnosis was based on exploratory laparotomy or necropsy. No gross pathological changes of chronic caudal bowel stenosis were found. The thickening of the intestinal wall therefore was postulated to be an idiopathic form of muscular hypertrophy. Neither an etiologic agent nor a clear pathophysiologic mechanism has been identified yet. An autonomic imbalance resulting in abnormal gut motility and prolonged spastic contraction is suspected. Hypertrophy of the circular and longitudinal muscular layers results in narrowing of the intestinal lumen and partial or complete obstruction. Abdominal pain is due to distension of the more cranial parts of the bowel. Intestinal wall rupture is one possible consequence of muscular hypertrophy (insufficiency of the wall), another may be the dilatation of the affected intestine. There is no possibility to treat this condition in horses because of the anatomic situation. The short mesoduodenum and a short attachment of the stomach prevent the duodenum from being exteriorized through a ventral midline incision -in contrast to the caudal small intestine (jejunum, ileum).

Ultrasonographic Diagnosis—idiopathic Muscular Hypertrophy of the Small Intestine in a Miniature Horse

“…Idiopathic muscular hypertrophy of the small intestine has been described in many species and occurs without mechanical obstruction as a stimulus for compensatory hypertrophy 1–4 . Secondary hypertrophy can occur when an obstructive or stenotic lesion is present to predispose the orad segment to become hypertrophic 1,3 .…”

“…Idiopathic muscular hypertrophy of the small intestine in horses tends to involve the ileum 1,2 and duodenum 4 . Surgical bypass without resection has been used successfully for treatment 1,2 .…”

Secondary chronic gastric impaction after idiopathic muscular ileum hypertrophy in a horse

“…Die Hypertrophie der Darmwandmuskulatur verursacht eine partielle oder komplette Lumenverlegung (Chaffin et al 1992). Die Muskelhypertrphie des Dünndarmes kann alle Dünn-darmabschnitte betreffen (Toth und Hollerrieder 2005), jedoch ist das Ileum die häufigste Lokalisation.…”

“…Die Pathogenese der primären Muskelhypertrophie des Ileums ist unklar. Vermutet wird eine vegetative Innervationsstörung, die eine abnorme Peristaltik und eine dauerhaft spastische Kontraktion des Ileums bewirkt (Rooney und Jeffcott 1968, Toth und Hollerrieder 2005 (Edwards 1997).…”