Neurologic signs and hyperammonemia in a horse with colic.
Abstract: A 23-year-old Thoroughbred gelding was referred for the evaluation of acute onset of ataxia and depression, and a 2-day history of fever. On physical examination, the gelding was profoundly depressed and 10-12% dehydrated. The horse appeared very unstable, with a wide-based stance in the hind limbs, severe symmetric ataxia in all 4 limbs, and proprioceptive deficits in both hind limbs. Nasogastric intubation produced 4 L of brown, fetid reflux, and rectal examination revealed mild small intestinal and cecal distention. Hematologic abnormalities included neutropenia with toxic change, compatible with acute inflammation and endotoxemia, and prolonged coagulation times. Serum biochemical abnormalities included prerenal azotemia. metabolic acidosis, and electrolyte abnormalities consistent with enteritis. Blood ammonia concentration was markedly increased (406 micromol/L; reference interval 4-49 micromol/L), however, serum bile acids concentration and hepatic enzyme activities were within reference intervals. Histopathologic examination of a liver biopsy revealed no abnormalities and results of tests for several infectious agents were negative. Clinical signs resolved with correction of the dehydration and electrolyte abnormalities and with antibiotic therapy. The horse was diagnosed with hyperammonemic neuropathy associated with gastrointestinal disease. In such cases, hyperammonemia is caused by increased production of ammonia by organisms in the gastrointestinal tract in combination with increased gut permeability that facilitates ammonia absorption.
Publication Date: 2006-06-20 PubMed ID: 16783725DOI: 10.1111/j.1939-165x.2006.tb00126.xGoogle Scholar: Lookup
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Summary
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The research article documents the case of a 23-year-old Thoroughbred gelding that developed neurological symptoms and hyperammonemia (elevated blood ammonia levels) related to gastrointestinal illness.
Case Description
- The horse in the study was a 23-year-old Thoroughbred gelding. The horse was brought in for evaluation due to sudden onset of ataxia (lack of muscle control) and depression, accompanied by a fever across a two-day period.
- During the physical examination, the horse displayed significant symptoms of depression and was revealed to be 10-12% dehydrated. It also had severe ataxia in all four limbs, with proprioceptive deficits (difficulty in sensing the position, location, orientation, and movement of the body and its parts) in the hind limbs.
Examination Findings and Diagnostics
- Nasogastric intubation was carried out (a process where a plastic tube is inserted through the nostril, down the throat, and into the stomach), which produced 4 liters of smelly, brown reflux. Rectal examination indicated mild small intestinal and cecal distention.
- A hematologic examination showed the presence of neutropenia (a lower number of neutrophils, a type of white blood cell), which is often a sign of acute inflammation and endotoxemia (presence of endotoxins in the blood).
- Further, prerenal azotemia (an elevated level of substances like urea and creatinine in the blood), metabolic acidosis (a condition that occurs when the body produces too much acid), and electrolyte imbalances typical of enteritis (inflammation of the small intestine) were noted.
- The blood ammonia concentration was significantly raised, pointing towards hyperammonemia. However, serum bile acids concentration and hepatic enzyme activities were within the normal range.
- A liver biopsy was conducted, the histopathologic examination of which revealed no anomalies.
- Tests for several potential infectious agents came out negative.
Diagnosis and Treatment
- The horse’s clinical signs were alleviated after the dehydration and electrolyte imbalances were rectified, and antibiotic therapy was administered.
- The horse was finally diagnosed with hyperammonemic neuropathy associated with gastrointestinal disease. This was attributed to an increased production of ammonia by organisms in the gut, combined with increased gut permeability, which allowed for more absorption of ammonia.
Cite This Article
APA
Sharkey LC, DeWitt S, Stockman C.
(2006).
Neurologic signs and hyperammonemia in a horse with colic.
Vet Clin Pathol, 35(2), 254-258.
https://doi.org/10.1111/j.1939-165x.2006.tb00126.x Publication
Researcher Affiliations
- Department of Biomedical Sciences, Tufts University School of Veterinary Medicine, North Grafton, MA, USA. shark009@umn.edu
MeSH Terms
- Animals
- Colic / complications
- Colic / veterinary
- Horse Diseases / blood
- Horse Diseases / physiopathology
- Horses
- Hyperammonemia / blood
- Hyperammonemia / complications
- Hyperammonemia / veterinary
- Male
- Nervous System Diseases / complications
- Nervous System Diseases / physiopathology
- Nervous System Diseases / veterinary
Citations
This article has been cited 2 times.- Yoon J, Park T, Kim A, Park J, Park BJ, Ahn HS, Go HJ, Kim DH, Jung S, Seo Y, Lee JB, Park SY, Song CS, Lee SW, Choi IS. First Clinical Case of Equine Parvovirus-Hepatitis-Related Theiler's Disease in Asia. Viruses 2021 Sep 24;13(10).
- McConachie E, Giguère S, Barton MH. Scoring System for Multiple Organ Dysfunction in Adult Horses with Acute Surgical Gastrointestinal Disease. J Vet Intern Med 2016 Jul;30(4):1276-83.
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