Page 571 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

546 CHAPTER 2

VetBooks.ir 2.150 PENILE LACERATIONS/
TRAUMA/HAEMATOMA

Definition/overview
Trauma to the penis can cause a variable amount
of injury, from minor swelling only to significant
haematoma of the vascular structures of the penis
or open lacerations with severe damage. All penile
injuries should be treated as immediate emergencies
due to the rapid onset of tissue oedema and swelling,
with potentially disastrous consequences for the ani-
mal’s breeding future.

Aetiology/pathophysiology
Trauma is most commonly caused by a kick from
a mare during attempted breeding, when the penis
is fully erect and at greatest risk of injury (see
Fig. 2.149). Tail hairs from the mare or suture
Fig. 2.150 Priapism in a grey pony gelding. material from a Caslick’s stitch may cause lacera-
tion of the stallion’s penis during breeding. The
penis may also suffer trauma during semen collec-
Management tion in situations where the thermometer has been
Priapism must be treated as a medical emergency. forgotten in the artificial vagina, or if the stallion
Early intervention is directed at limiting the depen- makes forceful thrusts against the phantom before
dent and gravitational effects, including massage, the collector can properly place the artificial vagina.
slings and emollient dressings, and may prevent A phantom constructed with the artificial vagina
long-term sequelae if the erection subsides within inside predisposes to penile injury during mount-
a few hours. Administration of anti-inflammatory ing or collection, particularly if the stallion slips and
agents are suggested. In the acute stages, adminis- loses footing. Proper construction, maintenance
tration of benztropine mesylate (8 mg i/v), a gan- and use of the phantom are essential for the stal-
glionic blocker, may help relieve the condition. lion’s safety.
Administration of 10 mg of 1% phenylephrine HCl
directly into the CCP if benztropine mesylate fails Clinical presentation
to resolve the priapism has also been suggested. In the case of lacerations, blood may be noticed in
In unresolved or more protracted cases, surgical the semen, dripping from the stallion’s penis or from
treatment under general anaesthesia may include the mare’s vulva after breeding. With blunt force
lavage of the CCP with heparinised saline to remove kicks, swelling occurs almost immediately and diag-
sludged blood or intervention to establish vascular nosis is obvious (Fig. 2.151).
shunts between the corpus cavernosum and the cor-
pus spongiosum. Differential diagnosis
Trauma to the penis must be differentiated from
Prognosis trauma to the prepuce. If the clinical presentation
For stallions with priapism that has not resolved is blood in the ejaculate, a urethral laceration should
quickly, the prognosis is generally poor. Damage to also be considered a potential cause.
the pudendal nerve and retractor penis muscles may
result in permanent penile paralysis, and fibrosis of the Diagnosis
CCP over time results in erectile dysfunction. Penile Thorough examination requires that the stal-
amputation may be required in refractory cases. lion’s penis is exteriorised, if it is not so already.