Cases of acute or subacute EGS usually die or are euthanased on humane grounds and/or due to a hopeless prognosis for survival (within 48 hours for acute cases or seven days for subacute cases, following the onset of clinical signs). For these cases, supportive care including treatment with intravenous fluids, pain relief and regular decompression of the stomach may be initiated until a more definitive clinical diagnosis is reached.
Treatment should only be attempted in cases of chronic EGS. Survival rates for chronic EGS range from 36% – 49%, increasing to 70% when cases are selected for treatment based on specific criteria, which include willingness to attempt to drink and swallow feed; retaining some ability to drink and swallow feed and the absence of continuous moderate to severe signs of colic. The severity of certain clinical signs is important for predicting outcome, and cases with the best chance of survival tend to show a significant improvement in their appetite and demeanour within the first month following onset of clinical signs.
There is no specific treatment for chronic EGS, and the only treatment with any proven efficacy is intensive nursing, which is prolonged, intensive and expensive. Some cases may require a period of hospitalisation with intravenous fluid therapy and/or feeding via stomach tube.
FEEDING CHRONIC EGS CASES
There is no “ideal diet” for chronic EGS cases, and as appetite and food preferences vary, a wide range/selection of different highly palatable feeds should be offered on a “little and often” basis (at least 4 – 5 times per day). It is well worth trying any different types of feed samples obtained from feed companies or feed shops/merchants, or by asking other horse owners for small amounts of anything different they have. Feeds can be warmed improve palatability and dampened to ease swallowing (molasses diluted with warm water or apple juice can be used to damp feeds); however owners should be aware that individual food preferences change frequently, and both wet and dry feeds should be offered. Some horses may require intensive encouragement to eat by hand feeding. They sometimes prefer to eat from raised buckets so over-the-door mangers/buckets in addition to their usual feed bucket(s) may be useful.
High-energy, high-protein feeds are best, such as high energy concentrate feeds (cereals and/or coarse mixes) or “all-in-one” commercially available mash feeds. Alfalfa is a useful fibre feed as it also contains good quality protein. Well soaked sugar beet pulp can be used to aid palatability and to dampen feeds, as can succulents (carrots, apples, swede etc.) which can be grated finely or blended to avoid the risk of choke. Oils, such as corn or vegetable oil, can be added to increase the energy content, but excessive amounts should be avoided as it can reduce palatability and may cause diarrhoea.
Other ideas to improve palatability include adding flavouring such as herbs, garlic, or biscuits to feeds and flavoured licks can also be provided. Foal milk pellets or milk replacer can be added to increase the energy content of feeds and high-energy human meal replacers, which are available from chemists/pharmacies, may also be useful. There is no evidence to support the use of probiotics and/or prebiotics in the treatment of EGS, but they may have a beneficial effect on gastrointestinal tract flora. It is very important to ensure adequate water intake, and water should be refreshed regularly.
OTHER ASPECTS OF NURSING CHRONIC EGS CASES
Animals with chronic EGS may be weak and depressed or lethargic, and sometimes do not appear to cope well with full time field turnout, therefore they should be stabled with a deep bed (which also has the advantage of allowing close monitoring of food and water intake plus the amount and nature of faeces they are passing). Regular in-hand walking exercise is beneficial and they should be given access to grass. As they improve, they can be turned out on good pasture, starting with 20 – 30 minutes per occasion and gradually increasing.
Where present, rhinitis sicca (where dried mucus nasal discharge accumulates in the nasal passages) can be uncomfortable, therefore the nostrils should be cleaned regularly to remove crusts of nasal discharge and petroleum jelly (e.g. Vaseline) can be applied inside the nostrils to reduce the damage to nasal mucosa. Anecdotally, the use of Vicks or other similar human decongestants may be beneficial.
Cases of chronic EGS often have a low body temperature, so should be kept warm. However, as they are prone to sweating, using a fleece or cooler-type rug is most appropriate. Regular grooming is important to avoid skin problems due to excessive sweating, but also increases human contact which appears to be beneficial.
MEDICAL TREATMENT FOR CHRONIC EGS CASES
During treatment, cases of chronic EGS may suffer from episodes of colic, especially after feeding. On some occasions, these colic episodes may be mild and self-limiting, resolving without the need for any medical treatment. However, management of colic episodes often requires veterinary attention to administer pain relief, usually with intravenous injections which are preferred as they do not adversely affect gastrointestinal motility.
Appetite stimulants (such as diazepam) have been used in the treatment of chronic EGS cases but were found to have no significant effect on appetite and resulted in undesirable side-effects including drowsiness and poor coordination/unsteadiness (ataxia).
A variety of lubricants and laxatives have been tried, including liquid paraffin and Dioctyl (a human laxative/stool softener). Liquid paraffin can be administered via a stomach if required. Aloe vera gel has also been used, as it not only acts as a laxative but has antioxidant and anti-inflammatory properties too. Unfortunately, aloe vera gel has to be administered daily via a stomach tube – a procedure which is resented by horses with rhinitis sicca, as passage of the stomach tube up the nasal cavity becomes uncomfortable. In the one small study that has evaluated its use, aloe vera was found to have no significant beneficial effect in treating chronic EGS cases.
Given the management and dietary changes involved in treating chronic EGS cases, affected horses can have a number of risk factors for equine gastric ulceration syndrome (EGUS); therefore specific treatment for EGUS may be indicated where recommended by the attending veterinary surgeon.
RECOVERY FROM CHRONIC EGS
Data from our EGS Surveillance Scheme indicates that, overall, around 50% of chronic EGS cases go on to recover from the disease. Recovery is a lengthy process, taking on average 6 – 12 months to regain their normal bodyweight, but can take even longer for those which require a longer period of hospitalisation. Around 80% of recovered cases return to their previous level of work, with an average of 12 months post-diagnosis to return to ridden work and up to 18 months to return to competition. One small survey of chronic EGS cases found that the most common problems observed in first 2 months post-hospitalisation included:
- Sweating (65% of cases)
- Hair coat abnormalities (58% of cases)
- Difficulty swallowing (48% of cases)
- Poor appetite (42% of cases)
- Colic episodes (23% of cases)
Choke can lead to a secondary complication of aspiration pneumonia where affected horses inhale food material – this can be treated with antibiotics but tends to be associated with a poor prognosis. Episodes of diarrhoea during recovery are fairly common (reported in around 30% of cases); however if diarrhoea becomes persistent there is an association with a poorer prognosis.
Once recovered, it is rare for affected horses to suffer from EGS again in the future, and the majority of cases appear to regain normal gastrointestinal tract function and motility. Interestingly, microscopic examination of tissue from recovered cases indicates that the characteristic nerve damage remains even following a complete recovery.
CHRONIC EGS SURVEY
There is limited information regarding the duration and extent of recovery, or factors that may affect recovery from chronic EGS. Additionally, there is little published evidence regarding clinical signs which veterinary surgeons and horse owners can use predict the likelihood of survival in affected horses and ponies. To address this, we have launched a new study which aims to investigate the management, treatment and outcome of chronic EGS cases. Find out how to take part in the chronic EGS survey here.
Each case of chronic EGS is different, so individual cases require a unique treatment plan. Your veterinary surgeon is the most important source of information about your horse or pony’s treatment for chronic EGS. If you would like further information, please feel free to contact us directly: Telephone: 01638 555399 or E-Mail: firstname.lastname@example.org
Highly experienced expert veterinary surgeons and nurses at the Dick Vet Equine Hospital, Royal (Dick) School of Veterinary Studies, University of Edinburgh are also happy to provide advice: Telephone: 0131 650 6253
Other useful sources of information include: An online downloadable leaflet about EGS produced by World Horse Welfare, available at: http://www.grasssickness.org.uk/wp-content/uploads/2013/10/Grass-sickness-WHW-e-booklet.pdf
A Facebook page hosted by a veterinary nurse experienced in EGS care, available at: https://www.facebook.com/TheGrassSicknessNurse