Equis ISSN 2398-2977

Testis: orchitis

Contributor(s): Annalisa Barrelet, Graham Munroe, Madeleine Campbell

Introduction

  • Orchitis is an inflammation of the testis.
  • Cause: trauma, infection, parasite migration, auto-immune.
  • Signs: testicular edema and pain. Pyrexia, anorexia and hindlimb lameness in bacterial infections; scrotal swelling and edema.
  • Diagnosis: history, clinical signs, semen evaluation, ultrasonography, testicular biopsy.
  • Treatment: cold water bathing, antimicrobials, NSAIDs.
  • Prognosis: good to guarded.

Pathogenesis

Etiology

Trauma

  • A kick to the scrotal area around coitus or teasing. If there is no skin penetration, the orchitis will normally remain non-septic.

Infection

Other causes

  • Parasite migration (Strongylus edentatus Strongylus spp) has been implicated occasionally as a cause of orchitis.
  • An anti-sperm autoimmune response may cause an orchitis or non-inflammatory degeneration (trauma → damage to the blood-testis barrier) ie testicular lacerations, biopsies, neoplasms, trauma.

Pathophysiology

  • Whatever the cause of orchitis, the initial pathophysiology and the sequelae if not effectively treated are the same, and center around spermatogenesis being adversely affected by an increase in testicular temperature. Normal testicular temperature (35°C/95°F) is below a horse’s body temperature and increases in temperature to 37°C/98.6°F for even 24 h can have an adverse effect on spermatogenesis for one spermatogenesis cycle (60 days).
  • Mechanical injury or infection → inflammation.
  • Acute cases may have increased intra-testicular pressure due to edematous (engorgement) swelling confined by the tunica albuginea.
  • Intra-testicular pressure and increased testicular temperature → disruption of spermatogenesis and may ultimately cause testicular degeneration if not effectively, promptly and successfully treated.
  • If blood:testis barrier gets disrupted, autoimmune response can reduce fertility.
  • Chronic cases will have irreversible atrophy of the seminiferous epithelium, fibrotic scarring and degeneration of the testis.
  • Fibrinous to sheet-like adhesions form between the testicular tunics as well as the epididymis.
  • The affected testis becomes small and firm in consistency.
  • Granuloma formation results from leakage of spermatozoa from seminiferous tubules and from associated epididymitis → epididymal obstruction → extravasation of sperm.
  • If prompt vigorous treatment is not given it is unlikely that total restoration of sperm production will occur.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Gonzalez M, Tibary A, Sellon D C & Daniels J (2008) Unilateral orchitis and epididymitis caused by Corynebacterium pseudotuberculosis in a stallion. Equine Vet Educ 20 (1), 30-36 VetMedResource.
  • Wilson K E, Dascanio J J, Duncan R, Delling U & Ladd S M (2007) Orchitis, epididymitis and pampiniform phlebitis in a stallion. Equine Vet Educ 19 (5), 239-243 VetMedResource.
  • Kasaback C M et al (1999) Theriogenology question of the month. Septic orchitis-periorchitis and epididymitis. JAVMA 215 (6), 787-9 PubMed.
  • Friedman R et al (1991) The effects of increased testicular temperature on spermatogenesis in the stallion. J Reprod Fertil Supp 44, 127-34 PubMed.
  • Zhang J et al (1990) Antisperm antibodies in the semen of a stallion following testicular trauma. Equine Vet J 22 (2), 138-141 PubMed.

Other sources of information

  • Beard W (2011) Abnormalities of the Testicles. In: Equine Reproduction. Eds: McKinnon A O, Squires E L, Vaala W E & Varner D D. 2nd edn. Wiley Blackwell. pp 1161-1162.


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