The following is an extract from a Peer Reviewed Article presented by Dr Josh Slater BVM&S PhD MRCVS
CLINICAL SIGNS OF LIVER FAILURE
Weight loss
Depression
Decrease appetite or anorexia
Hepatic encephalopathy:
yawning
head pressing
aimless manic walking
circling
ataxia
Ventral oedema
Photosensitisation
Jaundice
Coagulopathy
LABORATORY INVESTIGATIONS
Plasma liver enzymes
GGT (gamma glutamyl transferase)
ALP (alkaline phosphatase)
AST (aspartate aminotransferase)
LDH (lactate dehydrogenase)
GLDH (glutamate dehydrogenase)
SDH (sorbitol dehydrogenase) Indicator levels for these tests are required.
Serum albumin
Serum bilirubin
Serum bile acids
BSP clearance
Liver biopsy / ultrasound
“ None of the laboratory investigations listed here should be used in isolation to investigate horses with suspected liver disease; a full panel of investigations is required to establish an accurate diagnosis and prognosis”
This section is in 2 parts. The first part is involved with why Ragwort is poisonous and how it does the damage it does. The second part will cover the actual symptoms of Ragwort Poisoning.
How is Ragwort Poisonous?
When a horse eats Ragwort, depending on the quantity eaten and the time period over which it has been eaten; a horse can get Ragwort Poisoning. When a horse eats a large quantity of Ragwort in a short space of time; for example if a bad batch of hay contains plenty of dried Ragwort which is then eaten freely by the horse due to it having no bitter taste like fresh Ragwort, the onset of the ragwort poisoning can be rapid. This is known as Acute Ragwort Poisoning.
On the other hand, if the horse or pony just picks up odd leaves and stems here and there, but on a regular basis, this will, if allowed to continue, still lead to Ragwort Poisoning, but due to the longterm basis, this is refered to as Chronic Ragwort Poisoning.
Pyrrolizidine Alkaloids
Ragwort contains compounds called Pyrrolizidine Alkaloids. In fact there are 8 different types. They are stored throughout the plant, in the sap. In fact, Ragwort isn't the only plant to contain these pyrrolizidine alkaloids. It is believed that as many as 3% of the worlds flowering plants contain them. That's about 6000 different species of plant to you and me. When stored in the plant, these compounds are non-toxic. However, when the plant is eaten, chemical processes in the intestines and liver change them into a highly toxic form, which is very damaging to the liver, and also to a lesser degree, to other organs such as the kidneys and lungs. The Pyrrolizidine Alkaloids, also known as PAs do not accumulate in the system. In fact, they are processed and excreted in 24-48 hours. This is often the reason for blood tests showing no evidence of Ragwort Poisoning. By the time time symptoms are evident and the bloods taken, the poisons are often long gone.
Acute Ragwort Poisoning
Both types of Ragwort poisoning; Acute or Chronic, will result in the same symptoms. They do however have slightly different effects on the liver. Acute Ragwort Poisoning, the result of eating a large amount of Ragwort and the subsequent rapid onset of symptoms, will result in a substancial amout on necrosis of the liver. (Necrosis means - death of cells or tissue due to injury or disease in a localised area.) The concentration of the PAs is so high, that vast amounts of liver tissue is killed. This then results in infection. As a result, the horse becomes very ill; for two reasons. Firstly the liver damage, and secondly the resulting infection. There can of course be two outcomes to this situation. Death or recovery. Usually, the damage is too severe for the animal to survive. However, if recovery happens, the dead liver tissue will be broken down and removed, but will be replaced by fibrous, connective tissue, which has no liver function. The animal will therefore have a greatly reduced area of functioning liver. By what extent the functioning liver is reduced is impossible to predict. It is the 'new' size of functioning liver that will determine the symptoms of liver failure. It may be that there are no symptoms, if the damage was indeed small, however, unlike the PAs, which do not accumulate in the system, the fibrous, connective and non-working replacement cells remain.
Chronic Ragwort Poisoning
Chronic Ragwort Poisoning is a drip, drip, drip version of the Acute Ragwort Poisoning. A little bit here, a little bit there, all doing a little bit more damage. A few more liver cells, killed off and replaced with fibrous tissue. Chronic Ragwort Poisoning does not usually result in liver infection. This is not the same as liver damage though. Sometimes, when blood samples are taken, certain liver enzymes can be found in the blood that indicates Chronic Ragwort Poisoning. However, in severe cases there are often not enough liver cells able to produce the enzymes that point to Chronic Ragwort Poisoning, therefore, it might appear that there is no evidence to suggest poisoning. Each PA that is metabolized does a bit more damage. This damage does accumulate, until approximately 75% of the liver is no longer functioning and the symptoms are then plain to see. At this point, there is very little that can be done. There is usually only one outcome.
Table to illustrate the organs affected by Pyrrolizidine Alkaloids of animal species
Species
Liver
Lung
Kidney
Heart
Pancreas
Gastric
Mucos*
Muscle
Man
Yes
Yes
Yes
Monkey
Yes
Yes
Yes
Yes
Horse
Yes
Yes
Yes
Pig
Yes
Yes
Yes
Sheep
Yes
Yes
Yes
Goat
Yes
Yes
Cattle
Yes
Yes
Dog
Yes
Mouse
Yes
Yes
Rat
Yes
Yes
Yes
Yes
Chicken
Yes
Yes
Yes
Turkey
Yes
Yes
Yes
This table is quite interesting. It clearly shows that it's not just our horses that are at risk. This information was taken from an article about Pyrrolizidine Alkaloids. It's quite long and involved, so if you can't sleep one night and want to find out more, check it out.
I must just point out that PAs are also found in other plants, so the results in this table do not necessarily refer to Ragwort alone. However, a PA is a PA, irrelevant of the source.
* From Roitman (1983)
Symptoms of Ragwort Poisoning
The problem with Ragwort Poisoning is the vagueness of the symptoms, and the fact that the damage that results in the visable symptoms only becomes apparent a good deal of time after the ingestion of the cause, sometimes as long as 6 months. If it was simply a case of sick horse with sprig of ragwort hanging out of his mouth, the cause of the problem would be obvious. But it's not. Added to this vagueness, is the fact that many of the symptoms that do become visable, could also be caused by other factors. Other issues are also involved that determine the symptoms and outcome. For example, younger animals seem to be more suceptable to poisoning than mature stock. The time of year that the plant matter is eaten, (how on earth would you establish that?) the rate at which a particular animal metabolizes the PAs and the particular mix of the PAs when they enter the system. For this reason, it has been very difficult to collect accurate data on the numbers of casualties to Ragwort Poisoning and calculate maximum lethal doses, and make estimates about the likelyhood of a particular animal surviving. As my Grandad used to say, '...a bit like knitting with fog...'
Symptoms of liver disease only become clear when the liver itself is no longer able to cope the the burden of the extra work due to the loss of funtional tissue. Some horses and ponies might show some signs of slight illness initially, but generally the symptoms develope quite suddenly.
Early signs include loss of appetite and weightloss, diarrhoea, depression and excessive sensitivity to sunlight (photosensitization), and mild jaundice. More severe signs include a range of abnormal behaviour and can include compulsive walking, circling, and head-pressing (against a wall perhaps,) and apparent blindness as well as extreme depression. These neurological symptoms are due to the toxic effects on the horses brain.
A Glimmer of Hope
Ferber, S. Horse Feb 2001
The magazine Horse recounts the recovery of a 17 year old Welsh Cob called Flyer.
The horse had been diagnosed with terminal liver failure and was due to be destroyed. given a last ditch chance the horse was prescribed homoeopathic treatment by Ainsworths.
GGT levels of 260 at the peak have returned to 31 over the course of the treatment and the horse has returned to apparent health.
Details of the treatment and the full story are published in the magazine Horse Feb 2001. Back issue copies are available if you send an email to ipcback@aol.com
This is part of the article.
Road to recovery
“I owe Flyer’s life to Lyndon for spotting the problem and to David and Jeanne for taking over his care and giving him the homoeopathic treatment he needed,” says Sue. “Although I’ve always had an open mind, I never thought homoeopathy would have such a positive effect. And the cost of the remedies was just £34! There must be other people with horses suffering from ragwort poisoning who believe the symptoms are something else and I hope reading my story can help them. It makes me angry to think I had done everything to prevent my horse from eating ragwort but it wasn’t enough. Once the plant has taken hold it should be treated with sprays. I feel I wasted my time pulling it up. The response of the local Council when I complained about ragwort growing on their land was, ‘can’t you move your horse?’ With an attitude like that, we’ll never be rid of this killer weed. Homoeopathy turned out to be my only resort. Ainsworths chief pharmacist, Tony Pinkus, says in Flyer’s case, where the liver has taken such a battering, the aims were to prevent liver failure, get rid of the toxins, repair the liver and take away the symptoms. Initially Nux vomica was used as a detoxifier to rapidly remove toxins and begin liver repair. The Carduus and Celidonium combination is a liver tonic, whose function is to repair the damage and restore the organ. The Senecio jacobeas being used to antidote other symptoms associated with ragwort poisoning.
Ainsworths publish a small book entitled ‘Horses and Homoeopathy, A Guide to Yard and Stable’. It is available online at our book shop at the princely sum of £4 plus carriage.
