Page 843 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

818 CHAPTER 4

VetBooks.ir Gastric decompression is critical and should be per- for complications such as laminitis or catheter-site
Affected animals should be closely monitored
formed early in the examination of any horse with
signs of severe abdominal pain. A NG tube should be
held until refluxing has ceased. Parenteral nutrition
left in place or passed frequently because large vol- thrombophlebitis. Food and water should be with-
umes of reflux can be produced. If more than 5 litres may be required in horses that continue to reflux for
of reflux are obtained, the stomach should be decom- several days. Oral medications should be avoided
pressed hourly. As the amount of reflux decreases, because of unpredictable absorption.
the frequency of decompression can be decreased.
Intravenous fluid therapy is almost invariably Prognosis
indicated because of dehydration, toxaemia and an The prognosis is reasonable if aggressive supportive
inability to provide oral water; greater than 100 care can be provided. Reported survival rates range
litres/day may be required in some cases. Electrolyte from 25% to 94%. Response to treatment is highly vari-
abnormalities can be associated with poor intesti- able. Some horses may cease refluxing within 24 hours,
nal motility, so serum or plasma electrolyte levels while others may continue to reflux for more than 1
should be monitored if possible. Supplementation week. The typical course of disease is 3–7 days and the
of the balanced electrolyte solution with potassium prognosis is good for horses that stop refluxing within
chloride or calcium borogluconate may be required. 72 hours. Complications such as laminitis are not
Total potassium supplementation should not exceed uncommon, and euthanasia is sometimes required for
1.0 mEq/kg/h. economic reasons if prolonged treatment is required.
The clinical signs of DPJ are very similar to those
of surgical small-intestinal lesions, therefore explor- LACTOSE INTOLERANCE
atory laparotomy is not uncommonly performed.
The decision on whether surgery is indicated can Definition/overview
be difficult and if unsure, it is often wise to err on Lactose intolerance is occasionally identified in foals.
the side of surgical intervention to ensure that a sur-
gical lesion is not overlooked. Hypoproteinaemia Aetiology/pathophysiology
may develop, and oncotic support may be required. Lactose intolerance occurs following damage to
Plasma may also be beneficial if signs of endotox- the small-intestinal villi. Typically, this is second-
aemia are present. Synthetic colloids can be used if ary to infectious causes of enterocolitis; however,
plasma is not available. the initial cause may not be identified in all cases.
It is unclear whether antimicrobials are required, Primary lactose intolerance has not been reported in
either for treatment of a primary infection or pre- foals. Lactase, the enzyme responsible for convert-
vention of bacterial translocation. Penicillin is often ing lactose into glucose and galactose, is normally
used because clostridial organisms may be involved. present in enterocytes on the tips of villi in the small
Broad-spectrum coverage is not unreasonable, intestine. Secondary lactose intolerance occurs when
but care should be taken when using aminoglyco- lactase-producing cells have been damaged. In foals
sides because of the potential for nephrotoxicity. it is usually associated with infectious enteritis.
Metronidazole (25–50 mg/kg p/r q8-12 h) has been Diarrhoea and colic are the main presenting signs.
used because of the suspected involvement of C. dif- Other clinical abnormalities are not common, and
ficile, but its efficacy is unclear. foals are typically bright and alert. Serious problems
Flunixin meglumine (1.1 mg/kg i/v q12 h) is use- are rare. Lactose intolerance should be considered in
ful for controlling pain, attenuating pain-induced foals that are bright and alert and yet have persistent
ileus and for purported ‘antiendotoxin’ effects. diarrhoea, particularly in those foals that have expe-
Other antiendotoxin therapies such as administra- rienced an episode of suspected infectious enteritis.
tion of polymyxin B (6000 IU/kg i/v q12 h) should Lactose intolerance may also be present transiently
be considered in toxaemic horses. Prokinetic therapy with enteritis of virtually any aetiology, but not be
has not yet been shown to be effective. readily apparent because of the primary disease.