Gastric Impaction - Horse

Gastric impaction can occur as a primary condition but is often diagnosed at surgery as a finding secondary to other disturbances in the intestinal tract. In some cases there be predisposing causes such as ulceration or fibrosis at the pylorus, whereas in other cases it ma occur spontaneously. Predisposing factors:

• Ingestion of certain feedstuffs including beet pulp, bran, straw, wheat and barley - beet pulp and bran can become dessicated within the stomach and may not become rehydrated by water or gastric secretions
• Dental disorders - roughage may be incompletely masticated
• Feeding a horse that has signs of colic - there may be poor gastric emptying associated with generalised decreased gastrointestinal motility

Clinical signs Abdominal discomfort If the signs are mild and resolve spontaenosuly or with analgesics, owners often inclined to feed the horse, worsening the imapction

Diagnosis Suspected if cannto pass NGT, with gastric disytension the gastoroesophageal junction can become distoreted makingit difficutl to pass an NGT If poorly macerated r digested feed material is recvered form the NGT when the horse has been starved for several hrs On rectal, spleen may be dispalced caudally andmedially (not specific) Endoscopy (not diagnostic for impaction and diffcult to assess gastric distnsion) Rads may help, will show diaphragm displaced crnaially

Trestment If suspected, horse should be tranferred with NGT in place to a faciltiy where surgery can be perfomed if necessary Medical tx can include gastric lavage to remove as much imcpated material as possible - may need to dne repeatedly 100-200ml 8%DSS may facilittae hydration of dessicated ingesta IV fluid and anlagesics sould also be given, altogh unliukely that IV fluids will resovle the imapction Gastric motility stimulants hsould be avpoided if the extent of the impaction is unkown to prvent gastrci rupture Those diagnosed at sx ay be treated iwth bethanoecol at 0.2mg/kg SC every 8hrs

Surgeyr Direct infusion of balanced polyionic fluids into the i,maopction through the stomach wall Stomach massaged to brea down oimapction and facilitate movement of lfuid into the ingesta Or fluid may be infused via NGT followed by massage of the sotmach Post-op starve for 48-72hrs Gastrocpsy indicated to cofnrum resolution of impaction and identyo any undelryign cuases in stomach

References

Mair, T.S, Divers, T.J, Ducharme, N.G (2002) Manual of Equine Gastroenterology, WB Saunders.