Advances in Laminitis, Part II, An Issue of Veterinary Clinics: Equine Practice

Christopher C. Pollitt

Description

This issue is the second half of the topic on laminitis, one of the most challenging diseases for the equine clinician to treat. Articles include endocrinopathic metabolism, equine metabolic syndrome, hyperinsulinemic laminitis, pasture associated laminitis, corticosteroid associated laminitis, supporting limb laminitis, pharmacological basis for the treatment of endocrinopathic laminitis, pain management of chronic laminitis, chronic laminitis: larval therapy, chronic laminitis foot support: support shoes, pasture management, diet and exercise, herd management, and much more!

Sujets

• Equine
• Veterinary Medicine
• Medical
• Médecine

Informations

• Publié par: Saunders
• Date de parution: 28 août 2010
• Nombre de lectures: 0
• EAN13: 9781455700769
• Langue: English
• Poids de l'ouvrage: 1 Mo

Extrait

Advances in Laminitis, Part II , Vol. 26, No. 2, August 2010
ISSN: 0749-0739
doi: 10.1016/S0749-0739(10)00058-1

Contributors
Veterinary Clinics of North America: Equine Practice
Advances in Laminitis, Part II
GUEST EDITOR: Christopher C. Pollitt
Australian Equine Laminitis Research Unit, School of Veterinary Science, The University of Queensland Gatton Campus, Gatton, QLD 4343, Australia
ISSN  0749-0739
Volume 26 • Number 2 • August 2010

Advances in Laminitis, Part II , Vol. 26, No. 2, August 2010
ISSN: 0749-0739
doi: 10.1016/S0749-0739(10)00059-3

Contents
Cover
Contributors
Forthcoming Issues
Preface Advances in Laminitis, Part II
Endocrinopathic Laminitis
Laminitis and the Equine Metabolic Syndrome
Hyperinsulinemic Laminitis
Current Concepts on the Pathophysiology of Pasture-Associated Laminitis
Corticosteroid-Associated Laminitis
Supporting Limb Laminitis
The Pharmacologic Basis for the Treatment of Endocrinopathic Laminitis
Neuropathic Pain Management in Chronic Laminitis
Digital Venography in Horses and Its Clinical Application in Europe
Pasture Management to Minimize the Risk of Equine Laminitis
Endocrinopathic Laminitis: Reducing the Risk Through Diet and Exercise
Field Treatment and Management of Endocrinopathic Laminitis in Horses and Ponies
Clinical Presentation, Diagnosis, and Prognosis of Chronic Laminitis in Europe
Farriery for Chronic Laminitis
Chronic Laminitis: Foot Management
Maggot Debridement Therapy for Laminitis
First Aid for the Laminitic Foot: Therapeutic and Mechanical Support
Index
Advances in Laminitis, Part II , Vol. 26, No. 2, August 2010
ISSN: 0749-0739
doi: 10.1016/S0749-0739(10)00060-X

Forthcoming Issues
Advances in Laminitis, Part II , Vol. 26, No. 2, August 2010
ISSN: 0749-0739
doi: 10.1016/j.cveq.2010.06.008

Preface Advances in Laminitis, Part II

Christopher C. Pollitt, BVSc, PhD,
Australian Equine Laminitis Research Unit School of Veterinary Science The University of Queensland Gatton Campus Gatton, QLD 4343, Australia
The Laminitis Institute University of Pennsylvania School of Veterinary Medicine New Bolton Center Kennett Square, PA 19348, USA
E-mail address: [e-mail]

Christopher C. Pollitt, BVSc, PhD, Guest Editor

If knowledge can create problems, it is not through ignorance that we can solve them.
—Isaac Asimov (1920–1992)
The current importance of laminitis is reflected in the decision by the editors to dedicate not just one, but two editions to the topic of laminitis. The first edition dealt mainly with laminitis associated with septic/inflammatory conditions ( Veterinary Clinics of North America: Equine Practice. Advances in Laminitis, Part 1. Volume 26, Number 1, April 2010 ) and this second edition concentrates on metabolic and endocrinopathic laminitis. Both have articles on treatment/preventive strategies and how to cope with chronic laminitis, the aftermath of the acute stage.
Over 10 years have passed since Dr. David Hood guest edited the landmark edition in the Veterinary Clinics of North America: Equine Practice series entitled Laminitis. Readers consulting the 1999 issue will find much that is current and not covered in either parts of the 2010 volume. However, in the 1999 volume, the word insulin was hardly mentioned and the term “equine metabolic syndrome” had yet to be coined. 1 Obesity was thought to influence laminitis outcome because of the weight factor, and the focus of endocrinology was corticosteroids and thyroid hormone. The systemic components of laminitis were consequential to laminitis, and pathology of the endocrine system was not perceived as a direct laminitis risk factor. Thus, in the intervening 10 years, there has been a veritable explosion of research into endocrinopathic laminitis, reflected in Part II by 9 of the 17 articles dedicated to this topic.
Laminitis associated with equine Cushing's syndrome, iatrogenic corticosteroid administration, pasture consumption, and equine metabolic syndrome are reviewed by various authors (McGowan, Johnson et al, Geor, Bailey, Durham, Menzies-Gow, and Walsh). Common to all these conditions is insulin resistance and hyperinsulinemia. Horses and ponies that have lost insulin sensitivity and have high serum insulin concentrations are more likely to develop laminitis and be euthanized soon thereafter. Insulin resistance and hyperinsulinemia, as genuine risk factors for laminitis, unify the pathophysiology of equine Cushing's syndrome, iatrogenic corticosteroid administration, pasture-associated laminitis, and equine metabolic syndrome. Studies involving prolonged intravenous infusion of supraphysiologic insulin into first ponies 2 and then horses 3 provide experimental evidence in support of the laminitogenic potential of insulin and is reviewed here by de Laat et al. An article on pasture management and another on diet and exercise further acknowledge the link between glucose metabolism, insulin, and laminitis.
In Advances in Laminitis, Part I, the information generated by computed tomographic scanning was manipulated into a virtual 3-dimensional model to illustrate the lamellar wedge of chronic laminitis. In Part II, Mimics software is used again, this time in conjunction with an intravascular contrast agent, to illustrate the effect of weight-bearing on the arterial circulation of the foot. Supporting limb laminitis (SLL) has long been the bane of orthopedic surgeons performing complex restorative operations on fractures in the opposite limb in horses. The article by van Eps et al reviews what little information there is on SLL and posits that a highly evolved mechanism, normally of benefit in circulating blood through the horse's foot during locomotion, traps the horse in a unique pathologic process that results in SLL.
The pain of chronic laminitis often becomes refractory to conventional treatment regimens. A new concept for laminitis science is the article by Driessen, which suggests this may be due to neuropathic pain (ie, pain due to a lesion or dysfunction of the sensory transmission pathways in both the peripheral and the central nervous systems). Understanding that laminitis pain is being amplified and is the product of complex neuropathologic processes affecting both the peripheral and the central somatosensory nervous system should lead to rethinking of how analgesia is achieved for our equine patients. Many of the foot support techniques we employ are inherently painful and effective analgesia is needed to gain sufficient time to assess their effectiveness. Thus, effective multimodal combinations of agents, targeting different sites within the nociceptive system, coupled with effective monitoring, must now be embraced if we are to claim claim “best practice” for our equine patients. More than just “bute” (phenylbutazone) is required.
Progress in understanding laminitis has certainly been made. In 2007, laminitis was described as “idiopathic inflammation or ischemia of the submural structures of the foot.” 4 In 2010, even the author of that statement agrees that, while idiopathic means of unknown cause, it is a bit of a stretch to use it in laminitis. No one ever refers to navicular disease/syndrome as idiopathic, but we know more about the pathogenesis of laminitis than navicular disease (Andrew Parks, personal communication, 2010).
The language surrounding laminitis will always be evolving and editors may not get to completely dictate the terminology used in their editions. 5 There are many ways to describe the pathologic anatomy of laminitis and some of the few “experts” in the field have developed personal nomenclatures and neologisms to describe what they see. There is little unity and considerable confusion. Most have resisted “the call for unified terminology” addressed by Parks and Mair in 2009, 5 and we still have “founder distance” instead of “vertical coronet extensor process distance.” The former is jargon and in common use among the cognoscenti (including myself), but the latter, much longer term, has precise meaning and can be used for morphometric studies of normal equid feet. It would be curious to use “founder distance” to measure the vertical distance between coronet and extensor process in the feet of normal horses that have never been touched by laminitis. Admittedly, for the purposes of objective measurement, coronet needs a precise definition and that of Eustace 6 , ie, “rim of palpable mature horn distal to the perioplic ring (coronary band),” is satisfactory.
There are many examples of nomenclature disunity in the articles that follow and no apologies are offered. Some of the authors are busy practitioners and were invited to recount their personal approaches to the laminitis problem. Thus we have divergent current opinion on laminitis diagnosis, prognosis, and therapy. Confused readers are advised to consult Parks and Mair, 5 Eustace, 6 or even the Illustrated Veterinary Anatomical Nomenclature, 7 particularly if they believe a new phenomenon or treatment has been discovered and novel terminology has to be coined---may it be brief, accurate, and descriptive.
There is a tendency in the laminitis literature toward ideology and dogma. Instead of going where the evidence leads, selected data are presented to reinforce strongly held concepts. Discussion and speculation becomes self-evident fact and research is directed to prove it. When reading this publication, much has to be