Rectal biopsy diagnosis in horses with clinical signs of intestinal disorders: a retrospective study of 116 cases

Abstract

Summary The histology from rectal biopsy specimens taken 1980–1990 on 131 occasions from 116 horses, age 1–18 years, with clinical signs of intestinal disease was evaluated and classified retrospectively. In 40 horses, autopsy results were studied for comparison. Biopsy specimens (21 horses) and post mortem rectal tissue (9 horses) from 30 healthy horses, age 4–22 years, were used as controls. In 105 clinical cases, a biopsy was performed on only one occasion, while repeat biopsy was performed in 11 cases. Specimens showed pathological changes in 60 horses. The findings were classified into acute, chronic or chronic active simple proctitis, granulomatous enteritis, eosinophilic granulomatosis/gastroenteritis, eosinophilic‐proctitis, erosive/ulcerative proctitis, pseudomembranous proctitis, proctitis with vasculitis and malignant lymphoma. Mild scattered neutrophil infiltration in the lamina propria was found in controls, but neutrophils in crypt or surface epithelia were abnormal findings. Depletion or hyperplasia of goblet cells sometimes accompanied inflammation. Simple proctitis occurred in association with malignant lymphoma and various inflammatory disorders of the gastrointestinal tract apparent at autopsy. Eosinophilic granulomatosis/gastroenteritis and granulomatous enteritis were diagnosed from biopsy specimens in 6 of 12 and 4 of 9 cases, respectively, of these diseases confirmed at autopsy. Reduction of acid mucins in goblet cells was a prominent feature of eosinophilic granulomatosis. Rectal biopsy was found to be a useful adjunct for evaluation of intestinal disease in the horse.

Chronic Idiopathic Inflammatory Bowel Diseases of the Horse

“…61,62 In dogs, LPE may be a prelymphomatous intestinal disease, 61,62 and this might also be the case in horses. 37 …”

“…60 Histologic examination of rectal biopsy of 9 horses with LPE led to antemortem diagnosis of LPE in 2 horses. 58, 60 A study correlating results of rectal biopsy with intestinal disease of horses suggests that lymphoid and plasma cells may occur in rectal tissue in many intestinal diseases, including granulomatous disease, cyathostomosis, and malignant lymphoma, 37 and therefore finding lymphocytic-plasmacytic proctitis, particularly if mild, may not justify a diagnosis of LPE.…”

“…Variation in neutrophil numbers may be caused by absorption of endotoxin through diseased intestinal mucosa. 22 Endotoxemia may cause neutropenia 6,7,9,[16][17][18][19][20][21][22][23][24][25] (%) n affected/n reported LPE [57][58][59][60] (%) n affected/n reported MEED 2,9,23,[63][64][65][66][67][68][69][70][71][72][73][74] 6,16,18,23,37 Unlikely to be diagnostic 34 50 6/12 37 Unlikely to be diagnostic 37 GGT, gamma-glutamyl transferase; n, number of horses. a Schumacher, unpublished. through margination and sequestration of circulating neutrophils, and a rebound neutrophilia may result from granulocytic hyperplasia in the bone marrow.…”

Systemic Granulomatous Disease in a Hungarian Warmblood Gelding

“…None of the spleen or rectal biopsy samples was representative of the final SGD diagnosis. Rectal biopsy samples have been reported to reflect intestinal pathology in only 50% of cases [17]. Spleen biopsies are also of limited value if there are focal pathologic changes.…”

Free fecal water in the horse – an unsolved problem

“…Bedingt durch eine Dysbiose könnte es, wie beim Menschen, zu einer immunvermittelten Entzündung der Darmschleimhaut kommen. Auch ist beschrieben, dass aufgrund einer Dysbiose die Absorption von Natrium und Wasser, durch eine verringerte Produktion von kurzkettigen Fettsäuren reduziert ist (Argenzio 1978, Wierup 1977, Owen et al 1983, Raymond 2010 (Trachsel et al 2010, Lindberg et al 1996. Hinweise auf entzündliche Veränderungen in der Rektumschleimhautbiopsie liefern eine Infiltration von neutrophilen Granulozyten in den Krypten oder oberflächlichen Epithelien, wohingegen eine moderate Infiltration von neutrophilen Granulozyten in der Lamina propria als physiologisch zu betrachten ist.…”