Penis: balanoposthitis in Horses (Equis) | Vetlexicon
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Penis: balanoposthitis

ISSN 2398-2977

Contributor(s) :


Synonym(s): Dourine

Introduction

  • Inflammation of the free body or glans of the penis (balanitis), in association with inflamed laminae of the prepuce (posthitis).
  • Associated definitions:
    • Priaprism: an erection or engorged penis in the absence of sexual stimulation.
    • Paraphimosis: the inability to retract the penis in to the  prepuce.
    • Phimosis: the inability to protrude the penis through the preputial orifice/os.
  • Cause: many potential causes; undoubtedly the most common cause is trauma, typically due to a breeding injury.
  • Signs: typically the penis is pendulous and protrudes from the prepuce; both the prepuce and penis are larger than normal, and/or distorted.
  • Diagnosis: history, clinical signs, visual and physical examination, ultrasonography, hematology and biochemistry, microbiology, biopsy, depending on the likelihood of differential diagnoses.
  • Treatment: dependent on cause; if the penis is enlarged and protruding from the preputial orifice, and/or the prepuce is swollen, reduction of the swelling and support of the organs is of paramount importance.
  • Prognosis: dependent on cause; good if traumatic and dealt with rapidly and aggressively post-insult; decreases with chronicity.
Print off the Owner factsheet on Dourine to give to your clients.

Presenting signs

  • Variable depending on etiology.
  • Typically: enlarged and prolapsed penis protruding through the preputial orifice, with a swollen and edematous prepuce.

Acute presentation

  • Enlarged, swollen, often bleeding, prolapsed and protruding penis from the preputial orifice which is swollen.

Geographic incidence

  • Variable depending on etiology.
  • Traumatic: worldwide.

Age predisposition

  • Usually mature, post-pubertal (>18 months of age).

Breed/Species predisposition

  • All breeds.

Public health considerations

  • Typically none.

Cost considerations

  • Diagnosis.
  • Ultrasonography.
  • Labor to treat the animal.
  • Drugs and materials to support the organs.
  • Loss of income for a breeding stallion.

Special risks

  • Stallion aggression.

Pathogenesis

Etiology

Predisposing factors

General
  • Traumatic: male horse (stallion), usually in the presence of a mare.

Specific

  • Depends on etiology.

Pathophysiology

  • Inflammation, regardless of inciting pathology, leads to swelling of one or bolth of the penis and prepuce. The dependent position of the organs leads to increased blood flow to the organs and increased permeability of blood vessels.
  • Extravasation of fluid into the interstitial space, leading to greater swelling and further inflammation, and an inflammatory cycle. The inflammatory cascade is exacerbated by the relatively inelastic preputial ring, and the restrictions imposed by the preputial orifice. With time, the chronic inflammation may lead to induration, ischemia and necrosis.

Timecourse

  • Depends on etiology.
  • In traumatic lesions, the tissues may not recover without treatment over a period of days.

Epidemiology

  • Regardless of cause, typically this is sporadic, with the exception of venereally transmitted diseases, especially 'dourine'.

Diagnosis

Presenting problems

  • Depends on etiology.
  • Timeliness is paramount.
  • Swollen, enlarged, painful and often pendulous penis and prepuce.

Client history

  • Traumatic: typically a breeding related history.
Bacterial infection
  • Recent trauma to penis and prepuce.

Clinical signs

  • Regardless of cause: enlarged, swollen penis usually protruding from the preputial orifice. The prepuce is often enlarged typically due to edema and is often distorted.

Diagnostic investigation

  • Full clinical examination.
  • Ultrasonography   Ultrasonography: reproductive tract - male  to determine the presence of edema, free fluid, and other potential abnormalities such as herniation and rupture of the corpus cavernosus penis (CCP) and/or the corpus spongiosum penis (CSP).

Confirmation of diagnosis

Discriminatory diagnostic features

  • Enlarged, swollen, edematous penis and prepuce.

Definitive diagnostic features

  • Full clinical examination/palpation.
  • Ultrasongraphic examination.

Histopathology findings

  • Depending on cause.
  • Useful for tumors, habronemiasis, etc.

Differential diagnosis

  • See differential diagnosis of clinical presentation.

Treatment

Initial symptomatic treatment

For traumatic balanoposthitis

  • Early intervention is critical to enhance the outcome of traumatic balanoposthitis.
  • Based on the history, and clinical signs, cold hydrotherapy (up to 20 min) should be instigated IMMEDIATELY; prior to the attendance of the veterinarian if possible.
  • Sedation is typically necessary for a safe and complete examination. Drugs chosen for this procedure should not exacerbate, or potentially exacerbate the problem (phenothiazines should probably not be administered unless inducing general anesthesia, as they have been implicated in causing penile paralysis/priapism. Administration of the benzodiazepine, diazepam   Diazepam  , may assist in alleviating potential aberrant behavior resulting from the trauma).
  • Anti-inflammatory drug treatment (corticosteroids   Therapeutics: glucocorticoids  or non-steroidal anti-inflammatory drugs (NSAIDs)   Therapeutics: anti-inflammatory drugs  ) is an integral part of the treatment regimen. The use of corticosteroids in a breeding animal should be carefully considered prior to administration.
  • Decreasing or reducing the edema using manual pressure, massage, various bandaging techniques, and therapeutic ultrasound treatment, will assist in returning the prolapsed penis within the prepuce. Hypertonic preparations, such as glycerine, sugar and salt may assist in removing the edema.
  • Maintaining viability of the skin with the use of topical emollient preparations, with or without antibiotic or disinfectant.
  • As a result of the presence of compromised tissue and local immunity, appropriate systemic antibiosis should be instigated.
  • Support of the swollen and prolapsed penis (paraphimosis   Penis: paraphimosis  ) and prepuce is one of the most important parts of the treatment process, regardless of cause. Methods for supporting the dependent organs include: nylon mesh, modified plastic bottles, pantyhose, proprietary supports, purse-string sutures, probang, bandaging, and the underpants support mechanism, which the author advocates.

DO NOT LET IT DANGLE!

  • Exercise, if and where possible, is useful in disseminating the ventral edema.
  • It is important to ensure that the animal is able to micturate.

Standard treatment

  • Depends on cause.

Monitoring

Traumatic

  • Monitor at least twice daily until the horse is able to retain the penis within the prepuce.
  • Thereafter, it is important to ensure adhesions do not occur between the penis and prepuce, so the horse must be encouraged to prolapse and retract the penis.

Subsequent management

Treatment

  • Once the edema has subsided, and the horse is able to fully retract his penis into the prepuce, no further drug treatments should be necessary.
  • The horse should be regularly exercised - ridden, hand-walked, horse-walked.

The horse should be euthanized if it has 'dourine'.

Monitoring

  • Ensure the penis and prepuce return to the normal anatomical relationship.
  • Once the inflammation has subsided, and erection and retraction occur normally, the animal should have sexual rest for about a week.
  • Thereafter breeding should be reintroduced with increasing frequency.
  • Dismount semen samples should be assessed in natural breeding situations, followed by pregnancy assessment of the mares.
  • Assisted breeding stallions should have continued assessment of motility and morphology, as well as the pregnancy assessment of mares.
  • Breeding behavior will need careful and continual monitoring.
  • The local or systemic effects of testicular hyperthermia may adversely affect semen production.

Prevention

Control

Traumatic

  • Appropriate breeding barn management.
  • Serving protocols such as only serving mares that are 'teasing', hobbles, 'breeding boots' on the hindlimbs of mares, the use of 'teaser stallions' to mount the mare before the breeding stallion, and the use of well trained and competent personnel.

Infectious

  • Quarantine.
  • Serology.
  • Swabbing.
  • Notification as necessary.

Outcomes

Prognosis

  • Depends on cause.

Expected response to treatment

  • Depends on cause and timeliness, typically good for full return to function for traumatic balanoposthitis.

Reasons for treatment failure

  • Reason for balanoposthitis, eg dourine, neoplasia.
  • Time between the occurrence of the condition and appropriate treatment.
  • Cicatrix formation dependent on damage of the integument and response to treatment.
  • Loss of sensation of the penis and glans penis will adversely affect the ability of the stallion to successfully inseminate a mare.
  • Formation of clots/thrombosis within the penis - typically they form between 2 and 5 h post-engorgement.

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Gunn A J et al (2013) Balanoposthitis and paraphimosis in the stallion. A novel support for an inflamed penis and prepuce. Clin Theriogenol (1), 45-55 VetMedResource.
  • Beltaire K A, Tanco V M & Bedford-Guaus S J (2011) Theriogenology question of the month. Trauma-induced paraphimosis. JAVMA 238 (2), 161-164 PubMed.

Other sources of information

  • Horserace Betting Levy Board (2016) Codes of Practice. 5th Floor, 21 Bloomsbury Street, London WC1B 3HF, UK. Tel: +44 (0)207 333 0043; Fax: +44 (0)207 333 0041; Email:enquiries@hblb.org.uk; Website:http://codes.hblb.org.uk.
  • Schumacher J & Varner D D (2011) Abnormalities of the Penis and Prepuce. In: Equine Reproduction II. Eds: McKinnon A O, Squires E L, Vaala W E & Varner D D. Wiley-Blackwell. pp 1130-1144.
  • Koch C, O'Brien T & Livesey M A (2009) How to Construct and Apply a Penile Repulsion Device (Probang) to Manage Paraphimosis. In: Proc Am Assoc Equine Pract. pp 338-341.
  • Frazer G S (2008) Stallion Reproductive Emergencies. In: Proc North Am Vet Conf. pp 106-109.
  • Boero M J (1990) A Simple technique for Conswervative Therapy of Acute Traumatic Paraphimosis in the Horse. In: Proc Am Assoc Equine Pract. pp 625-628.