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| HorseAdvice.com » Diseases of Horses » Endocrine System » Pituitary Pars Intermedia Dysfunction (PPID): Equine Cushing's » |
| Discussion on Is it more than cushings? | |
| Author | Message |
| Member: Kick |
Posted on Wednesday, Oct 22, 2003 - 7:41 pm: It is happening again!!!! Last year (2002) beginning in October, my 20 year old horse, Apache, experienced the following: "Since October, Apache, has been experiencing lots of pain. Unlike his typical foundering signs that occur in the spring, the pain seemed to have started in his back legs and there wasn't any major heat around his hoof hairline. Now he seems to be sore in all legs. He appears to be very stiff legged. At times his coat would be matted like he had been sweating heavily. His joints in all legs pop when he walks. He seems to be depressed. He lays flat out on his side occasionally raising up to check his surroundings. We immediately put him in the barn/corral but that didn't seem to help. December 1, 2002, we started giving him Bute (2 grams twice per day) and Pent-flex for his joints. He seems to be moving much better but still not back to normal. When I reduce the Bute to 1 grams twice per day, his movement gets worse. Last Thursday, the vet came out and confirmed he was sore in all four hooves. He x-rayed his front feet. Results indicated Apache's coffin bone has rotated 15 and 25 degrees in his right and left foot, respectively. In his left foot, his coffin bone is ¼ inch from the bottom of his foot. The vet indicated it is typically ½ inch. The vet suggested Apache's condition resulted from his foundering and didn't offer any advice for improving his condition."After reading your advice regarding Cushing's Disease and working with my vet, at the end of December 2002, Apache was started on Pergolide (1cc once per day). After about two weeks, he improved greatly. He stayed out on pasture with open access to hay (which he didn't eat) and mineral salt and fed a small amount of southern states equine senior (12 ounces per day). Observations over the year were: he remained at excellent weight (has always been a little overweight until this year), terrific attitude, first spring we didn't have to limit his grazing, joint popping went away, and his hooves hadn't looked better. Now, it is October 2003, and he is experiencing the same symptoms he had last year. A trend...missing something in his diet...??? help... He and his companion are in a small paddock. In consultation with my vet, I started giving Apache 1 cc of pergolide twice a day, one in the morning and one in the afternoon. Any advice would be greatly appreciated. |
| Moderator: DrO |
Posted on Thursday, Oct 23, 2003 - 10:32 am: Hello Kim,Unfortunately Equine Cushinoid disease is a progressive condition and the pergolide does not hold forever. That you are having to increase the dosage is normal so you have already done what I would recommend. Of course routine therapy for the founder should be pursued also. DrO |
| Member: Kick |
Posted on Thursday, Oct 23, 2003 - 1:03 pm: It just seems that there may have been a pattern developing with the time of the year he is experiencing these symptoms. I wanted to make sure he wasn't having some sort of deficiency in his diet as a result of fall foliage, etc. Also, wanted to post to see if anyone else had noted their cushings horse to have a harder time during this time of year. Generally, what type of pergolide dosage increase is common with time?Also, is there any expected time frame that the pergolide remains effective? Thanks! |
| Member: Sallytwh |
Posted on Thursday, Oct 23, 2003 - 2:57 pm: Kim...yes Cushings is progressive but there are other things that can be done besides the Pergolide. Diet is very important and balancing the mineral intake will greatly improve his condition especially for the founder. There are many others of us with Cushing horses that have had to deal with your situation and have found that diet does come into play. First get him off of the Senior feed. This is one of the worst grains you can give to a Cushing horse as it is extruded and therefore digested more thoroughly, which is great for bad teeth but not for Cushings and laminitis. Also, no pasture and yes the pasture may be the culprit at this time of the year...get him on grass hay and beet pulp without molassas and rice bran...you can get the ratios and amounts for this if you contact me email.Hang in there as you may be able to help him quite a lot yet. Sally |
| Moderator: DrO |
Posted on Friday, Oct 24, 2003 - 8:50 am: Cases vary tremendously on rate of progress and rate of change Kim. You must treat your horse as a individual. I did not mean to imply that pergolide is the only therapy and all of management factors are covered in detail in our articles on Cushings and Founder. But Kim and I have discussed this last year.I do disagree with Sandra about Equine Senior and have found it very useful in Cushinoid cases where weight loss is a problem. It would be more helpful Sandra to discuss your suggestions in an open forum so that we can discuss the pros and cons of your suggestions. DrO |
| Member: Kick |
Posted on Friday, Oct 24, 2003 - 9:41 am: Apache seems to be improving with the three days of the pergolide increase (1cc twice per day). Just like last year, he doesn't seem to have foundered. His symptoms aren't like the other times he foundered: warm hooves, rest one leg then the other all the time, lying down most of the time. He seems to be having other symptoms: all four legs being stiff, joints popping when he walks, mini steps when he first gets up with improvements once he gets going. I am not giving him anything for arthritic conditions...should I? I worry about mixing too many things. He has free access to loose minerals, loose white salt, fresh water and has been in about a 0.5 acre field with his long time companion for about 6 weeks. The field contains a mixture of bermuda (30%), fescue (30%), crab grass (30%), and some weeds. It hasn't been fertilized or conditioned for a couple of years. This summer and the past year, they had open access to a 20 acre field with similar grasses including orchard grass and a wooded area containing several nut trees. Apache loves the nuts...I wonder if the nuts had anything to do with his reoccurrence. Always searching for answers. Sally, I am very interested in your suggestions. All help and support is greatly appreciated. |
| Moderator: DrO |
Posted on Saturday, Oct 25, 2003 - 11:45 am: Possibly, if you have good evidence of arthritis but these are classic signs for mild founder too.I would not give access to both nonmineralized and mineralized salt: though there may be a "appetite" for salt there is not an appetite for the trace minerals. So when trace minerals are deficient in the diet, if they are consuming the nontrace mineral salt they will remain deficient. I know there are individuals who feel strongly different and that horses will consume it if they need it, it just ain't true. What type nuts..exactly. DrO |
| Member: Westks |
Posted on Saturday, Oct 25, 2003 - 12:33 pm: An observation about salt and trace mineral blocks before my mares were bred they visited each type consuming almost evenly. Now they are bred They are hardly touching the plain salt block and are really going after the trace mineral at twice the rate before. So anyone that has doubts about the need for trace mineral block my evidence is in BOLD here. |
| Member: Sallytwh |
Posted on Saturday, Oct 25, 2003 - 5:12 pm: Dr.O...not to be argumentative but Equine Senior tends to raise the insulin level and that is not something that Cushinoid cases can maintain for very long without worsening their condition. Cushings in Horses has been compared to Type II Diabetes and as such carbohydrates are not indicated.I really didn't want to get into a problem on the list as the last time I mentioned another list I believe I hurt your feelings and that sure isn't my intention. I have tried to find an email address for you personally but didn't have any luck. I do, however, from time to time feel I have to jump in and say something to someone that I really feel is in need of other information. As with Insulin Resistance or Diabetes itself, Cushing Horses would not improve with medications only but are in real need to watch their diets. The metabolic state of most of these horses is very precarious and should in all cases be taken into consideration. The other list that I mentioned has as of today 1011 members that all have one or more horse with Cushings or Insulin Resistant horses. All of these people are involved with Cushings Disease and are making progress as a whole in finding what will help their horses. There are several vets on the list that have given much time, research and expertise to this effort and I believe that they are really on the cutting edge of Cushings care. The information that has been discussed and researched has concluded that a prudent feeding schedule is desirable and helpful, below I am quoting from one of the files of this list: - "Most important is control of the starch and sugar level in the diet. This means eliminating ALL grains, pelleted feeds made with grains (read the ingredients on the label), supplements with a grain base, carrots, apples and access to grass. (Some stages of grass growth and/or specific grass species may be OK for some horses. Need to determine on an individual basis.) - Feeding of grass hay only, or grass hay with some soaked beet pulp to replace grain. Some horses are OK with small amounts of rice bran as well (2 oz/lb of beet pulp). - Analysis of hay to make sure NSC (nonstructural carbohydrate levels - primarily sugars in hays) is below 15% for severely insulin resistant horses, no more than 20% for any insulin resistant horse - Analysis of mineral levels in hay to allow selection or mixing of a supplement that specifically provides what the horse needs (see other files)". I have a sub group to this list for our local area in the Pacific Northwest that deals with local matters such as where to get the medicines at the best price and what hay is available etc. We have worked out a pelleted horse feed with a local manufacturer and they run analysis on each batch of Timothy or Orchard Grass hay that is pelleted and have these results analysed by a well known vet that specializes in the metabolic horse and has written for many publications including the Horse Journal and has written seven books on horses. These results are then balanced to that particular hay and minerals are mixed to suppliment that batch of pellets. These pellets contain no preservatives or binders. Then the owners can suppliment with long stemmed hay of the same batch along with beet pulp without molassas and with some stablized rice bran. Each horse may have individual needs that can be addressed as well....medicine etc.. I personally, have two of my own Cushing horses and one other that is a boarder. This does not make me a veterinarian but a proactive owner that has in the past also lost 4 others to undiagnosed Cushings. In years past the Cushing horse was diagnosed as "oh well, he is just getting old" and not given much or any consideration by the medical practice but now that is changing and more and more vets are becoming involved with Cushing as horses live longer and are better cared for. Please understand that I read Horse Advice regularly and find you to be of the greatest help with horses in all areas. I pay my dues each year and certainly get all my moneys worth from this list. In no way am I trying to contradict your knowledge but only to add to whatever can be helpful to these horses. If you would like the particulars on these groups let me know and you can personally go there and read the files and archives. I don't want to name them without your permission. SallyTWH |
| Moderator: DrO |
Posted on Sunday, Oct 26, 2003 - 11:31 am: Thanks Sally,Do not worry about posting other sites we encourage the exchange of information and if these sites are truly valuable I try to include them in the articles and thanks for the concern about my feelings. But that is not my problem with your post, the problem is a lack of understanding of what is known about the pathogenesis of Equine Cushinoid disease and confusing this disease with other diseases like primary insulin resistant "Type 2 Diabetes". Let's consider the relation between glucose metabolism and Equine Cushinoid Disease. Studies have found that somewhere between 25 to 75 % of the horses with EC have elevated glucose, elevated insulin, and a decreased insulin responsiveness (type 2 diabetes). The reason for the great range is that different researchers have used different lab values as normal. Let’s say the middle numbers might be close to the true number of cushinoid horses with abnormal glucose metabolism. Realize however that even at this level that 22% of horses and 30 % of ponies that have no disease have these levels. So we must account for these facts: 1) that 1/2 the horses with EC do not have measurable glucose abnormalities 2) using glucose/insulin normal lab values low enough to raise the number of EC horses to be considered insulin resistant to the above value about 1/4 of the of normal horses have glucose abnormalities. So insulin resistance and type two diabetes is commonly found in Cushinoid horses but not always and the clinical signs of Cushings can be present even when the horses have normal glucose levels, insulin levels, and even a normal insulin response curve. Let's look at another set of facts. There is recognized a primary Type 2 Diabetes of young horses. These horses instead of having many of the problems of Cushinoid horses are just the opposite: they are easy keeping horses to the point that they remain obese on even pasture alone. Using the facts presented about EC and primary rype 2 diabetes let’s take what I see as a few logical steps using these facts: Abnormalities of glucose metabolism do not seem to have a strong relation to the diseases signs seen with EC. If this is true is it logical to base therapy on this theory? We are aware that there is a prognostic correlation between worsening glucose metabolism and worsening disease state in some but not all EC horses. But is there a causal relationship? To illustrate why this might not be consider a speeding car. As you go faster the wind noise increases and the speedometer registers higher but does the speedometer cause the wind noise? They are correlated but not causal. I believe the exceptions in cases of EC and the lack of similar clinical signs seen in primary type 2 diabetics make a strong causality seem unlikely. There is one clinical entity that is similar between primary type 2 diabetic horses and Cushinoid horses and that is they both founder easy. However the pathogenesis of the founder in both cases remains unknown and though rapidly digested sugars and starches may play a role in both cases there are better established theories about why this is than abnormal glucose metabolism (see the articles on Cushings and Founder for more on this). I continue to watch the research on this closely however. Don’t get me wrong, many of the management suggestions you make have merit:
Currently our understanding of EC is rudimentary and a bit of a enigma. The clinical signs very closely look like the Cushings disease of people and dogs caused by elevated cortisol. However the cortisol levels in horses are normal to decreased???! Currently it presumed that the increased levels of hormones released by the piturtary have cortisol like activities on peripheral tissues, one of which is insulin resistance, but this is conjectured and other theories are out there. I will continue to look for the truth in what you say, I just have not seen it yet. I have been working on an article on Peripheral Cushings or type 2 diabetics for several years now and the problem has been that there is little more information than that made through the University of Michigan several years ago, however I think we will see if we can't get this published in the next month or two to better explain what we know. DrO |
| Member: Kick |
Posted on Monday, Oct 27, 2003 - 10:17 am: Acorns and hickory nuts. However, I think he was primarily consuming acorns because that's where I noticed him most. He seems back to normal now but I am still giving him 1cc of pergolyde twice a day. Should I reduce it back or continue at this level? Almost too scared to make any changes but the pergolyde is so expensive. I will remove the white salt. The loose minerals have salt in the mixture. Thanks so much! |
| Member: Sallytwh |
Posted on Monday, Oct 27, 2003 - 4:59 pm: Dr O:Do not worry about posting other sites we encourage the exchange of information and if these sites are truly valuable I try to include them in the articles and thanks for the concern about my feelings. But that is not my problem with your post, the problem is a lack of understanding of what is known about the pathogenesis of Equine Cushinoid disease and confusing this disease with other diseases like primary insulin resistant "Type 2 Diabetes". Response: Makes no difference to the horse, or in how the condition behaves, if the IR is primary or secondary. -------- Dr O: Let's consider the relation between glucose metabolism and Equine Cushinoid Disease. Studies have found that somewhere between 25 to 75 % of the horses with EC have elevated glucose elevated insulin and a decreased insulin responsiveness (type 2 diabetes). The reason for the great range is that different researchers have used different lab values as normal. Response: Can you provide references for those figures? Many studies (see files below) show a much higher incidence of glucose/insulin abnormalities. Also, since lab normal ranges always tend to err on the side of too high, this would mean that the number with problems is actually underestimated, not overestimated. ----------- Dr.O: Let’s say the middle numbers might be close to the true number of cushinoid horses with abnormal glucose metabolism. Realize however than even at this level that 22% of horses and 30 % of ponies that have no disease have these levels. Response: Again, what are the references for these numbers? ------------- Dr. O: So we must account for these facts: 1) that 1/2 the horses with EC do not have measurable glucose abnormalities 2) using glucose/insulin normal lab values low enough to raise the number of EC horses to be considered insulin resistant to the above value about 1/4 of the of normal horses have glucose abnormalities Response: There are many problems beyond what lab normals are chosen to define abnormals. Absolutely true that there are horses with classical coat changes of Cushings that do not have elevated glucose and insulin. There are even some (usually thoroughbreds and other 'hot" breeds) that may go for years with coat changes and noglucose/insulin changes. However, as the disease advances the bulk of the reports suggest that IR becomes evident in a very high percentage, if not 100%. Other individuals show IR/laminitis much earlier in the course of the disease. Important to note that in our group of over 1000 horses, about half of which are EC cases, it is far more common to find elevated insulin than elevated glucose. The elevated glucose seems to be a hallmark of very advanced IR, actually the true type II diabetes state, while IR with maintenance of glucose in the normal to high normal range is a common finding. Also true that many more horses are assumed to have EC than actually have the diagnosis confirmed, or diagnosis is made using tests of highly questionable value (such as loss of cortisol diurnal rhythm, which by the developer's own admission has as much as a 35% false positive rate). Loss of muscle mass and poor shedding are also nonspecific aging changes, and there are a variety of causes for difficulty holding weight in older horses. --------- Dr. O: So insulin resistance and type two diabetes is commonly found in Cushinoid horses but it is not a primary problem and the clinical signs of Cushings are present even when the horses have normal glucose levels, insulin levels, and even a normal insulin response curve. Response: Which clinical signs are you referring to here? Yes, some Cushing's cases have the abnormal hair coat without insulin/glucose changes, at least initially, may even have some weight/muscle loss (which may or may not be related to their tumor), but these horses typically are doing well otherwise, not laminitic, etc.. and, except for the classically abnormal Cushings coat, it's impossible to say whether problems such as holding weight are actually related to the Cushings per se or are for other reasons (poor chewing, decreased digestive efficiency, insufficient quality of diet, etc.) ---------- Dr. O: Let's look at another set of facts. There is recognized a primary Type 2 Diabetes of young horses. Response: If you mean very young horses, insulin sensitivity takes a while to develop. If you mean younger adult horses, most of these are insulin resistant but not diabetic - i.e., they do not have elevated blood sugar, only elevated insulin and abnormal glucose response curves. ------------------ Dr O: These horses instead of having many of the problems of Cushinoid horses are just the opposite: easy keeping horses to the point that they remain obese on even pasture alone. Response: The weight/muscle loss problem is seen with advanced Cushing's, not the early stages. Many insulin resistant Cushing's horses were in fact overweight, with the same abnormal fat distribution patterns (above the orbits, neck, tail base) in their earlier stages. Although one theory of the cause of IR in non-Cushing's horses is that they too have aberrant cortisol levels, this has not been proven. If they don't, the fact that true Cushing's horses do have abnormal cortisol production is likely a factor in their advanced muscle loss. Corticosteroids also directly inhibit protein metabolism. ------------------ Dr. O: Using these facts let’s take what I see as a few logical steps using these facts: Abnormalities of glucose metabolism do not seem to have a strong relation to the diseases signs seen with EC and therefore is it logical to base therapy on this theory? Response: Have to disagree with that, as above. Am not saying though that the abnormalities of glucose metabolism are the root of all EC problems; only that taking measures to correct that problem can benefit the Cushing's, or the non-Cushing's IR, horse or pony in terms of helping them maintain their weight in a normal range and avoid laminitis. -------------- Dr. O: We are aware that there is a correlation between worsening glucose metabolism and worsening disease state in some but not all EC horses. But there is not necessarily a causal relationship. In fact the exceptions in cases of EC and the lack of similar clinical signs in primary type 2 diabetics make direct causality seem unlikely. Response: When talking specifically about weight loss, laminitis and to a great extent lethargy as well, most if not all EC horses with worsening of these problems will indeed have worsening glucose metabolism and in our experience addressing this by careful diet control has excellent results. Should also mention here that horses and ponies with advanced IR that is not Cushing's related can also progress to the stage of weight loss rather than weight gain. ----------------- Dr. O: There is one similarity between primary type 2 diabetic horses and Cushinoid horses however and that is they both founder easy. However the pathogenesis of the founder in both cases remains unknown and though rapidly digested sugars and starches may play a role in both cases there are better established theories about why this is than abnormal glucose metabolism (see the articles on Cushings and Founder for more on this). I continue to watch the research on this closely however. Response: You must be talking about theories related to endotoxin, activation of inflammatory enzymes and vasoactive amine production in horses that develop laminitis on grass or grain. Some of these are well documented, some are only theories, but the important thing they all have in common is that for laminitis to occur there must be an overload of either simple sugars/starches or highly fermentable complex plant sugars like fructan (actually, grasses don't contain much fructan, mostly levan). However, with insulin resistance even a very small amount of grain or short periods of grazing can trigger laminitis, with intakes way too low to be causing the kind of colonic upset needed for those other factors to operate. It is well known from work with people and other animals that insulin resistance results in circulatory problems such as vasospasm, a pro-inflammatory state and also increased clotting tendencies. All of these are well documented causes of laminitis and may be the mechanism with insulin resistance too. Cortisol itself also directly makes vessels more prone to spasm: Eyre P, Elmes PJ, Strickland S. Corticosteroid-potentiated vascular responses of the equine digit: a possible pharmacological basis for laminitis. Am J Vet Res 1979 Jan;40(1):135-8. ------------- Dr. O: Don’t get me wrong, many of the management suggestions you make havemerit:We have been suggesting that foundering horses of any cause be removed from grain diets for over 20 years now but the reasons are different and better documented than the ones you conjecture. Response: Only for grain overloads, not for normally fed amounts of grain. There has to be a reason why some horses can tolerate grain feeding, even very high levels of grain feeding, without ever developing problems with laminitis with other horses and many ponies cannot be fed even small amounts of grain (or grass) without getting laminitic. Insulin resistance/carbohydrate intolerance seems to be the reason for many of them. ----------- Dr.O: We have been recommending high fat diets for the treatment of poor keeping horses for over 10 years (see the article on Cushinoid Disease, Poor Keepers, or Fat in the Diet). Response: High fat diets worsen IR in other species, and in ponies as well. No studies available on the effects with IR horses but because of the potential for worsening of the IR we tend to avoid high fat. ---------------- Dr. O: We have been interested in primary type 2 diabetes and its relation to obesity and founder for over 5 years(see the article on Founder or the insert on “Peripheral Cushings” in the article on Cushinoid Disease).But I think iis important that we be clear on what we know and why we do what we do in order to make the most accurate diagnostic, therapeutic, and prognostic assessments. I too have had old horses with Cushings and I provide the direct medical care for several dozen older horses with Cushings, most without the benefit of pergolide. Response: Are these confirmed Cushing's cases, by appropriate blood work? Again, I'm not saying that every old horse or every Cushing's horse needs sugar/starch restriction, only the ones that are insulin resistant. The diet is safe and effective for any horse though, including older horses having trouble holding weight, so if you're not closely monitoring insulins it can't hurt to be safe. ------------ Dr.O: I have found Equine Senior extremely helpful in the management of these older horses with weight loss and poor teeth. Response: Absolutely, but not a safe feed for a horse with insulin resistance. ------------- Dr. O: Currently our understanding of EC is rudimentary a bit of a enigma.The clinical signs very closely look like the Cushings disease of people and dogs caused by elevated cortisol. However the cortisol levels in horses are normal to decreased???! Response: Single readings of cortisol are not diagnostic in any species, including human or canine Cushings. Urinary cortisol:creatinine ratios or 24 hour multiple samplings must be done to get a better idea but even then cortisol levels are not an acceptable way to diagnose Cushing's in any species. Cortisol levels are only a screening test and even if within normal it is always necessary to move on to better diagnostic tests if the symptoms suggest Cushing's. ---------- Dr. O: Currently it presumed that the increased levels of hormones released by the piturtary have cortisol like activities on peripheral tissues, one of which is insulin resistance, but this is conjectured and other theories are out there. Response: What other theories are out there to explain the insulin resistance (progressing to actualdiabetes in advanced cases)? ---------------- } I have been working on an article of Peripheral Cushings or type 2 diabetics for several years now and the problem has been that there is little more information than that made through the University of Michigan several years ago, Response: Dr. Philip Johnson of University of Missouri spoke on this topic last year. He's also currently preparing a paper co-authored by one of the vets on our Cushings list, who is doing the details of the dietary control part. She has also written a section in the new edition of Dr. Andrea Floyd and Dr. Richard Mansmann's Equine Podiatry textbook (Elsevier) on insulin resistance, laminitis and dietary control. That text will be going to press shortly. Files: Vet Rec. 1993 Dec 11;133(24):594-7. Related Articles, Links Equine pituitary neoplasia: a clinical report of 21 cases (1990-1992). van der Kolk JH, Kalsbeek HC, van Garderen E, Wensing T, Breukink HJ. Department of Large Animal Medicine and Nutrition, Veterinary Faculty, Utrecht University, The Netherlands. The records of 21 horses with an adenoma of the pars intermedia of the pituitary gland were reviewed. The animals comprised nine Dutch warmblood horses and 12 ponies. They ranged in age from 12 to 30 years (mean +/- sem 21 +/- 1.3 years) for 20 of the horses, and comprised 13 geldings and eight mares. All the animals showed hirsutism. In 1991, nine horses were diagnosed as having the adenoma, equivalent to 0.5 per cent of the horses examined in 1991. The mean +/- sem survival time of four of the horses (from discharge to the development of complications which required euthanasia) was 192 +/- 59 days (range 120 to 368 days). Routine biochemical measurements were within their normal ranges except for a high alkaline phosphatase activity (768 +/- 487 iu/litre) and a high plasma glucose concentration (7.8 +/- 0.9 mmol/litre) in 16 of the horses; only six had a glucose concentration above 9.0 mmol/litre. (NOTE: Glucose of 7.8 mmol/L = 140 mg/dl, clearly abnormal). 76.1% with abnormal glucose in this study. Am J Vet Res. 1986 Mar;47(3):570-2. Related Articles, Links Equine intravenous glucose tolerance test: glucose and insulin responses of healthy horses fed grain or hay and of horses with pituitary adenoma. Garcia MC, Beech J. Intravenous glucose tolerance testing (0.5 g/kg of body weight) was done on 2 groups of healthy horses maintained with hay (group 1, n = 5) and with hay plus grain supplementation (group 2, n = 5) and on a group of horses with clinically diagnosed pituitary adenoma (group 3, n = 10). Healthy horses showed an immediate increase of plasma glucose concentration after the IV glucose injection, with return of values to base line in 1 hour. Group 3 horses showed resting hyperglycemia and a delayed return of glucose values to base line (3 hours). Group 3 horses showed resting hyperinsulinemia and a feeble (nonsignificant) response to the glycemic stimulus, with gradual decrease of insulin values to base line. In addition to the apparently reduced tissue sensitivity to insulin in group 3 horses, as evidenced by hyperglycemia, hyperinsulinemia, and protracted glucose and insulin curves, the initial decrease in the insulin/glucose ratio indicates that there was secretory deficiency in response to acute IV glucose loading. |
| Moderator: DrO |
Posted on Tuesday, Oct 28, 2003 - 11:31 am: Thank you for the very involved reply. I hope members will take the time to read this discussion as it sits on some of the most interesting question in equine medicine today.Many of your above statements I do not argue with but they do not address my last post which was a response to your post of Oct 25th where you state that EC is comparable to T2D and that Equine Senior raises insulin levels and that this is something that Cushinoid horses cannot stand. Though EC horses often have a secondary T2D they are not the same disease or even really comparable as their clinical signs are quite different. The crux of our initial disagreement revolves around whether Equine Senior is “one of the worst grains you can give to a EC horse”. We both agree that foundered horses should not be on grains of any kind. But you also seemed to say that no EC horse should be on it. I say it depends on his condition and his response to diet, even if the horse is T2D: what do you do when the diet you recommend will not keep weight on? I personally think its balanced nutrition, along with significant amounts of fat and protein make for a excellent choice for hard keepers and that its processing greatly aids in digestion of a horse that more likely than not will have tooth issues. The glycemic index of a food is of uncertain significance even in humans as the American Diabetes Association has called into question the usefulness of the glycemic index for managing human diabetes. To answer your direct questions: 1)The reference for the numbers on comparing clinically normal and diseased horses is from Couetil L er al: Plasma adrenocorticotropin concentration in healthy horses and in horses with clinical signs of hyperadrenocorticism, J. Vet. Internal Medicince 10:1-6, 1996. 2)I know of no lab bias to report artificially adjusted abnormal values. 3)I am talking about the whole constellation of clinical signs associated with Equine Cushings (EC). 4)The problem with assuming that Type 2 Diabetes (T2D) in EC is due solely to the pituitary factors ignores that there are many T2D without EC (see below). Other potential causes associated with T2D are genetic and obesity. As you state some of these horses go on to become EC as the majority of all horses do that live well into their 20's. Vet Rec. 2001 Oct 13;149(15):449-52 Measurement of basal serum insulin concentration in the diagnosis of Cushing's disease in ponies. Reeves HJ, Lees R, McGowan CM. The Royal Veterinary College, Hatfield, Hertfordshire. A high basal plasma or serum insulin concentration is commonly accepted as an indicator of Cushing's disease in horses. The results of the combined dexamethasone suppression test and thyrotropin-releasing hormone stimulation test were compared with the basal insulin concentrations and insulin response tests of eight hyperinsulinaemic and insulin-resistant ponies with clinical histories of chronic or recurrent laminitis that were suspected of having Cushing's disease. Seven of the eight ponies had normal responses to the combined test indicating that basal insulin concentrations are not a specific indicator of the disease. Addressing some of the controversial issues you bring up above: You comment about fat and T2D in horses ignores many complex issues not the least of which is that the amount of fat recommend for humans with DM is at levels well above that the horse normally would be at. The role of dietary fat and human diabetes remains uncertain, though the ADA does recommend a low saturated fat level (around 10%). You characterize the interpretation of the grain overload model of founder as only having relevance to horses that gorge on grain: I see no reason to believe this as these vasoactive products are always present and differing sensitivity to these chemicals for a variety of reasons could account for many cases of founder. The role of abnormal glucose metabolism and its effect on gross and micro circulation and the role in founder are extremely interesting topics that I have debated before on these boards. We know that these horses have trouble with founder and I look forward to the research that illustrates the reasons for this but currently it is all theory and assuming it is true, how does that change our current recommendations? Lack of support and costs associated with the use of chromium and the poor support for micro-management of minerals that are almost always abundant in the diet do not warrant their costs in diagnosis or as therapy. Of course I know the research supporting the possible mechanisms of mineral therapy, but being T2D myself for a decade now, I can attest to the weakness of the research and the personal lack of effect of these minerals when supplemented. DrO |
| Moderator: DrO |
Posted on Tuesday, Oct 28, 2003 - 11:36 am: Kim, I would not immdiately reduce the pergolide, see if things stay stable for several weeks then you can begin to lower it. I was concerned there might be black walnuts out there. Though acorns are listed as toxic they are frequently consumed by horses without problems, which are usually GI in nature. If you would like a possible relation: disturbance to the GI tract may result in increased released or absortion of some of the chemicals that are implicated in founder. Maybe you should take steps to limit access to the acorns.DrO |
| Member: Aannk |
Posted on Tuesday, Oct 28, 2003 - 12:02 pm: All,I must put something out here. I am a type 1, juvenile immune caused diabetic. Just to clarify, the glycemic index is vital for the control of diabetes, type 2 and 1. I beleive insulin resistance of any type must be treated with low carbohydrate foods. Alicia |
| Moderator: DrO |
Posted on Tuesday, Oct 28, 2003 - 1:08 pm: Hello Alicia,I know this pretty new stuff and is also still quite controversial, but much research lately has concluded that the glycemic index has a limited value for managing diabetes. This report best summarises these recent controversies. I don't put this out as the final word, but to note the complexity of even seemingly straight forward issues. Note the emphasis using italics is mine: Am J Clin Nutr. 2003 Oct;78(4):858S-864S. Sugars and starch in the nutritional management of diabetes mellitus. Kelley DE. Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh, PA, USA. kelley@msx.dept-med.pitt.edu Nutritional recommendations, long recognized as an important aspect of diabetes mellitus treatment, have also been an area of persistent controversy, particularly regarding the proportions and types of carbohydrate and fat. This review addresses the role of sugars within medical nutrition therapy for diabetes mellitus. Nutritional recommendations for diabetes mellitus treatment were revised recently. The new guidelines do not specifically restrict intake of sugars, although general recommendations are made for including fiber, whole grains, vegetables, and fruits within dietary selections containing starches. For carbohydrates, the principle focus is on overall caloric amounts. In type 1 diabetes the most effective approach to the control of postprandial hyperglycemia continues to be adjustment of premeal doses of insulin on the basis of carbohydrate counting. In type 2 diabetes, in addition to a focus on caloric content of carbohydrate, consideration continues to be given to the role of the glycemic index as a determinant of postprandial hyperglycemia and overall metabolic control. Nevertheless, consensus recommendations do not support widespread use of the glycemic index. An area of some change is a more clear endorsement of including monounsaturated fatty acids. Current recommendations are that monounsaturated fatty acids and carbohydrates combined should provide 60-70% of daily energy intake, with individual flexibility in the respective proportions, whereas intake of saturated fats is limited to < 10% of energy intake. This new emphasis reflects greater awareness of the importance of responding to individual and cultural dietary preferences and the need to address treatment of both hyperglycemia and dyslipidemia in diabetes mellitus. DrO |
| Member: Aannk |
Posted on Tuesday, Oct 28, 2003 - 1:13 pm: The glycemic index may or may not be important, but myself, and millions of diabetics world wide, do well on low carbohydrate diets. This is more what I was trying to get across. Low carb and low glycemic tend to go hand in hand, but I agree that it doesn't always correspond with better management, as low carbo almost ALWAYS does.Alicia |
| Moderator: DrO |
Posted on Tuesday, Oct 28, 2003 - 4:29 pm: Alicia, you will get no argument from me on this as it has been almost 2 years since I have had a white potato. If you think I am promoting the indiscriminate use of rapidly digestible carbohydrate in equine nutrtion above either you have misunderstood what I have said or I have done a poor job of explaining my position. Let me be clear, maximizing exposure to forage and minimzing the exposure to grains is the basis of good nutrition of all horses. But you did not need me to explain this as this has been specifcally outlined in our article on general nutrtion since its first version, written 20 years ago. Of course it is updated almost 5 times yearly but still completely revolves around this basic premise.I would like to clarify a point that is not clear in your post Alicia and may be misinterpreted. That is that glycemic index of a food and its carbohydrate content are the same. The glycemic index of a food depends on the amount of rapidly digestible carbohydrate and is used to measure the glucose spike following ingestion. Complex carbohydrates on a weight for weight basis with starch have much lower glycemic indexes. At the extreme indigestible carbohydrates, often called fiber, have a glycemic index approaching 0. DrO |
| Member: Aannk |
Posted on Wednesday, Oct 29, 2003 - 10:05 am: Dr. O.,I have to admit I didn't read your posts thoroughly, sorry. I do now realize that you don't think high carb is good, and I was mistaken in what you were trying to say. Also, I didn't mean to imply that GI and carb counts are the same. For me, high glycemic foods are worse than low. The system does work for me, but not everyone who is diabetic. On the other hand, every type 1 diabetic has to know how many carbs they are eating to correctly administer insulin. I know a bunch who don't do that, and don't do too badly, but they are the ones who eat the same stuff every day, and know how much insulin to inject. I count carbs, and take insulin via an insulin pump. The GI of foods helps me understand sometimes why a packet of table sugar doesn't help me recover from a low blood sugar as quickly as, say fruit juice. It may be coincidence, but high GI foods definatley raise my blood sugars quickly. I hope that makes my other posts clear  Alicia |
| New Member: Jkiviat |
Posted on Tuesday, Apr 11, 2006 - 6:54 am: My 27 yo TB mare was diagnosed with Cushings over a year ago based on clinical presentation and general labs; no dex suppression test was performed. She responded well to Pergolide (1mg/day) until January when she began to DrOp weight and lose significant muscle mass. I switched her to Equine Senior (5 lb/ day) and she has free choice of grass hay, but continues to lose weight and is lethargic. I'm considering adding corn oil or a weight-builder supplement. Any suggestions?Joy |
| Member: Paul303 |
Posted on Friday, Apr 14, 2006 - 12:40 am: Joy: Keep in mind that Cushings can be progressive. My 26 yr old Cushings mare did well for about a year on 1mg. Permax following diagnosis. On re-test ( ACTH - which really isn't considered definitive ) due to a decided worsening of symptoms, the Vet raised her to 1.5mg. where she is, so far, doing OK again.You might start by testing her in case she needs her medication increased. |
| Member: Osakr |
Posted on Monday, Nov 6, 2006 - 12:29 am: Dr. Oglesby,Is keeping a cushing horse on alfalfa cubes contraindicated Thanks |
| Moderator: DrO |
Posted on Monday, Nov 6, 2006 - 7:09 am: Hello Omar,Our recommendations for feeding horses with Cushings, including the use of alfalfa in such horses, is in the article on Cushings, accessible from the navigation bar above. DrO |
| New Member: pezhie1 |
Posted on Monday, Nov 2, 2009 - 5:47 pm: I notice that even though these posts are relatively old, no one has mentioned chaste berry for Cushings horses. I have a 19 year old mare who was laminitic when I rescued her 6 months ago, and in addition to the pergolide which I began giving her daily as soon as she was diagnosed with the blood test, I also changed her diet immediately to as low a carb/sugar base as I could. She gets grass hay and beet pulp or a packaged feed called "Integrity Lo Carb" in the morning to which I add the pergolide and an eighth cup of chaste berry powder with a little linseed oil splash to bind the powder to the pellets. I have been experimenting with Stevia tincture which I made and which I have in a spray bottle that I squirt once on top and then stir it all up in the bucket. This is because all this non-sugary feed was boring my sweet-toothed girl to pieces. I'm not sure how much the stevia is helping....she knows it's not molasses...but she does eat everything eventually. I plan on adding a bit of soy to this mix to try and get some more weight on her now that she isn't in so much pain in her feet. In six months she has gone from totally sunken muscle tone, inflamed and swollen legs, and an inability to walk or move without pain - not to mention the depression and the ragged coat and leaky eyes to now trotting and squealing and exerting her dominance over our younger mare as if she was still a youngster herself. She no longer has the pain, and she's regained the muscle tone on her hips and topline, as well as her neck and chest. She is vocal and responsive whenever her name is called and she is being ridden about twice a week by a young girl weighing about 120 lbs with no visible signs of pain or favoring any leg. I believe that adding the chaste berry did a lot to boost the action of the pergolide and to help her fight inflamation better. There is a great published study on chaste berry that they did in the UK for laminitis horses. Reading that is what convinced me to try it. Thanks so much for this site Dr. O. I am a little anxious in the anticipation of the progression of her Cushings down the road. What will signify to me that the tumors are growing? How long will it be before something bad will happen? If I stay on top of her hormone balancing and low sugar diet, won't things stabilize for a long time? What happens as Cushings worsens? Also what do you know about biotin or anything else that can help hooves to grow ? I have to be careful about the carb levels in pre-packaged feed for this... |
| Moderator: DrO |
Posted on Tuesday, Nov 3, 2009 - 7:58 am: Hello Peg,We cover chasteberry and the commercial product Horminase in the article on Cushings. However many folks have discussed it before and running a search on the term will bring those discussions up. Concering questions about your own horse let me help you get started off right as there are several advantages to you if your personal discussions are kept separate from others:
You will find the "Start New Discussion" button at the bottom of the "List of Discussions ". This list is on the parent page to this discussion along with an "Article". Getting there is easy, for example on this page:
Before posting you should review the article as you will find helpful information. If it does not answer your question and you don't see a related discussion that answers your question you should "Start a New Discussion" with your question. For more on this and other important information see Help & Information on Using This Site » Welcome to The Horseman's Advisor. Thanks for helping us stay organized. DrO PS, by copying your post you can easily paste it into a new discussion. PPS, many members prefer not to display there full name in their posts. You can edit this in your profile to display your chosen moniker. DrO |
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