Peer-reviewed veterinary case report
Encephalopathy with idiopathic hyperammonaemia and Alzheimer type II astrocytes in equidae.
- Journal:
- Equine veterinary journal
- Year:
- 1999
- Authors:
- Hasel, K M et al.
- Affiliation:
- Department of Pathology · United States
- Species:
- horse
Plain-English summary
In three mature female horses of different breeds, the animals experienced colic (abdominal pain) and depression for two weeks before developing serious brain issues. These brain problems included unusual behavior, anxiety, heavy sweating, and in one horse, a severe muscle spasm that caused it to arch its back. Blood tests showed that their ammonia levels were about ten times higher than normal. When the horses were examined after death, they had bleeding in their intestines, and further tests revealed changes in brain cells that are similar to those seen in Alzheimer’s disease. The researchers think that the high ammonia levels might have come from problems in the intestines or from bacteria in the colon, rather than from liver or kidney issues. Unfortunately, the outcome for these horses was not positive.
Abstract
In 3 mature female horses of varying breeds, episodes of colic and depression for 14 days preceded an encephalopathic disorder with maniacal behaviour, anxiety, profuse sweating and, in one case, terminal opisthotonus. Blood ammonia levels were elevated approximately 10-fold. At necropsy, there were gastrointestinal serosal and mesenteric haemorrhages. Histologically, all 3 cases revealed diffuse Alzheimer type II astrocytes in the cerebral grey matter. Alzheimer type II astrocytes were glial fibrillary acidic protein (GFAP) negative or only weakly positive, weakly S-100 positive, and vimentin negative. In the absence of primary hepatic and/or renal lesions, an increase in intestinal ammonia absorption due to ileus or increased ammonia production by colonic bacteria is hypothesised.
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Search related cases →Original publication: https://pubmed.ncbi.nlm.nih.gov/10596928/