• Open Access

Diagnostic Frequency, Response to Therapy, and Long-Term Prognosis among Horses and Ponies with Pituitary Par Intermedia Dysfunction, 1993–2004

Authors

  • B.W. Rohrbach,

    1. Departments of Comparative Medicine
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  • J.R. Stafford,

    1. Departments of Comparative Medicine
    Current affiliation:
    1. Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN
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  • R.S.W. Clermont,

    1. Departments of Comparative Medicine
    Current affiliation:
    1. Veterinary Teaching Hospital, Chesapeake
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  • S.M. Reed,

    1. Department of Veterinary Clinical Sciences, Ohio State University, Columbus, OH
    Current affiliation:
    1. Rood & Riddle Equine Hospital, Lexington, KY
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  • H.C. Schott II,

    1. Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI
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  • F.M. Andrews

    Corresponding author
    1. Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN
    Current affiliation:
    1. Equine Health Studies Program, Department of Veterinary Clinical Sciences, Louisiana State University, School of Veterinary Medicine, Baton Rouge, LA
    • Departments of Comparative Medicine
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  • Work was performed at the University of Tennessee, College of Veterinary Medicine, Knoxville, TN.

Corresponding author: Dr Frank M. Andrews, Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Skip Bertman Drive, Baton Rouge, LA 70803; e-mail: fandrews@lsu.edu

Abstract

Background

Pituitary pars intermedia dysfunction (PPID) is common in older horses.

Objectives

To determine diagnosis frequency, prognostic factors, long-term survival, and owner satisfaction with treatment.

Animals

Medical records from horses diagnosed with PPID, 1993–2004.

Methods

A retrospective cohort design with data collected from the Veterinary Medical Data Base (VMDB) and a cohort of 3 VTHs. Proportional accessions, annual incidence, and demographics were compared for all accessions. During the same period, a subset of medical records (n = 44) was extracted and owners (n = 34) contacted to obtain long-term follow-up information.

Results

Diagnoses of PPID were reported for 217 horses that presented to VTHs and were reported to the VMDB. Proportional diagnosis increased from 0.25/1,000 in 1993 to 3.72/1,000 in 2002. For 44 horses included in the follow-up study, the most commons signs were hirsutism (84%) and laminitis (50%). Of 34 horse owners contacted, the average time from onset of signs to diagnosis was 180 days. Improvement in ≥ 1 signs, 2 months after diagnosis, was reported by 9/22 (41%) of horse owners. Clinical signs and clinicopathologic data were not associated with survival, and 50% of horses were alive 4.6 years after diagnosis. Cause of death among horses (15/20; 85%) was euthanasia, and 11/15 (73%) were euthanized because of conditions associated with PPID. Most horse owners (28/29; 97%) said they would treat a second horse for PPID.

Conclusion and Clinical Importance

PPID was diagnosed with increasing frequency, and 50% of horses survived 4.5 years after diagnosis. Owners were satisfied with their horses' quality of life and would treat a second horse if diagnosed.

Ancillary