Page 974 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Urinary system 949

VetBooks.ir incontinence are outlined under their respective pri- is reasonably good. Urine scalding can be avoided
mary causes elsewhere in this chapter.
by routine cleaning. In cases of suspected oestrogen-
In cases of urinary incontinence where primary
onate (4 mg/kg i/m q48 h) can be administered.
disease can be managed successfully, the prognosis associated incontinence in mares, oestradiol cypi-

DISEASES OF THE URETHRA

URETHRAL TRAUMA AND due to dramatic pressure changes during ejacula-
URETHRAL DEFECTS tion. Haemorrhage from penile varicose veins is also
possible.
Definition/overview
Urethral trauma and defects have become increas- Clinical presentation
ingly recognised in male horses. Mild cases express Urethral trauma typically results in haematuria at
themselves only with haematuria. Breeding dis- the end of urination and haemospermia in stallions.
ability and urinary tract obstruction are possible in Pollakiuria may be present in some cases. Penile,
complicated cases. vaginal or perineal trauma may be apparent.

Aetiology/pathophysiology Differential diagnosis
Trauma to the penis (Fig. 7.27), breeding inju- Differential diagnoses include urolithiasis, urethri-
ries, dystocia, masturbation control devices (stal- tis, cystitis, bladder paralysis, neoplasia and sabulous
lion rings), post-surgical scar tissue, prolonged and urolithiasis.
traumatic urinary catheterisation, endoscopy of the
distal urinary tract and urethral calculi can lead to Diagnosis
urethral trauma. Tears of the proximal urethra at No obvious clinical signs are usually present except
the level of the ischial arch have recently been found for haematuria. Close examination should be per-
to be more significant. It is possible that the condi- formed to look for signs of trauma. The penis
tion is the result of corpus spongiosum penis damage should be extruded, examined visually and care-
fully palpated. The bladder should be palpated p/r.
Cystoscopy and urethroscopy should be carried out
7.27 to confirm the urethral lesion (Figs. 7.28, 7.29).
Care should be taken during urethroscopy to prevent
exacerbation of a urethral lesion. If there is a ques-
tion about the patency of the penile urethra, a ret-
rograde urethrogram can be performed (Fig. 7.30).
Ultrasonography can be useful in the examination of
surrounding tissue for any evidence of foreign bod-
ies, scars or haematomas.
Urinalysis and urine culture should be performed.
These are usually unremarkable, with haematuria
being the only abnormality. Anaemia may be pres-
ent if urethral bleeding is prolonged or severe.

Fig. 7.27 Penile trauma. This stallion injured Management
himself jumping over a fence with an erect penis. Note Most minor lesions to the urethra will resolve spon-
the oedema around the genitals, which may also be taneously. If lesions communicate with the adjacent
caused by urethral rupture and urine leakage. corpus spongiosum penis, spontaneous resolution