Acquired Nonneoplastic Disorders of the Male External Genitalia

Chapter 224


Acquired Nonneoplastic Disorders of the Male External Genitalia



The subject of disorders of the male external genitalia is too vast to cover thoroughly in this concise chapter. Neoplastic disorders of the male genitalia are discussed in Chapter 222 in this text. Therefore the focus of this chapter is on acquired conditions affecting the male external genitalia. Congenital disorders (e.g., cryptorchidism, persistent frenulum, hypospadias) are not included.



Penis and Prepuce



Paraphimosis and Phimosis


Paraphimosis is the inability to withdraw completely the penis into the prepuce. Paraphimosis is the opposite of phimosis, which is the inability to extrude the penis from the prepuce. Paraphimosis occurs 14 times more frequently than phimosis. It is seen most commonly in young, intact male dogs (boxers and poodles are overrepresented in case reports), is uncommon in castrated male dogs, and is rare in cats. Although still uncommon, phimosis is reported in the literature more frequently in cats than dogs.


The causes of paraphimosis are summarized in Box 224-1. The cranial preputial muscles normally draw the prepuce cranially about 1 cm in front of the tip of the penis. If the preputial musculature cannot retract effectively the penis into the prepuce because of muscular or neurologic deficits, then the prepuce may end at the tip of the penis or be shorter than the penis, allowing the tip of the penis to remain exposed continuously. About 30% of paraphimosis cases are idiopathic (Papazoglou, 2001). Like paraphimosis, phimosis can have a number of developmental or acquired causes. The acquired causes of phimosis are summarized in Box 224-1.



Box 224-1   Acquired Causes of Paraphimosis and Phimosis



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Paraphimosis


The diagnosis of paraphimosis typically is made by visual inspection of the penis protruding from the prepuce. The entire length of the penis and prepuce should be examined to determine if any other urogenital abnormalities exist. Chronic protrusion of the penis causes the penile mucosa to become dry, congested, erythematous, inflamed, edematous, ischemic, excoriated, and painful, which may lead to self-mutilation. Evidence or history of trauma or concurrent stranguria indicates the need for radiographs of the penis to determine if the os penis has been fractured.


The treatment goal is to replace the penis in the prepuce as soon as possible and prevent recurrence of the problem. Penile size (edema and inflammation) can be reduced using cold compression bandages, massage with topical hyperosmotic solutions, and systemic antiinflammatory therapy. Urine production should be monitored closely. If in doubt about urethral patency and/or bladder integrity, the clinician should place a urinary catheter. General anesthesia facilitates replacing the penis into the prepuce by reducing preputial muscle contraction. Before attempting manual replacement of the penis, the clinician should clip the hair around the preputial opening (in the dog) or pluck this hair (in the cat) and apply copious amounts of lubricant to the penile mucosa. If the penis cannot be replaced manually, surgery is required. If a preputiotomy is performed, the tissues should be closed carefully to the original state. Penile and preputial surgical repair requires a thorough understanding of normal anatomy and basic reconstruction principles. Castration often is performed in conjunction with surgical correction of paraphimosis, but castration alone is not successful in correcting paraphimosis.


If the penis will not stay within the prepuce after replacement, additional surgery is needed. These techniques include a purse-string suture at the preputial orifice, preputial orifice narrowing, preputial lengthening (preputioplasty), cranial preputial advancement, preputial muscle myorrhaphy, and phallopexy. Phallopexy is the author’s preferred method for penile retention, which is a technique of creating a permanent adhesion between the dorsal surface of the penis and the preputial mucosa (Somerville and Anderson, 2001). If the penis cannot be returned to the prepuce or if it has been severely damaged, a complete or subtotal penile amputation with concurrent urethrostomy should be performed (Pavletic and O’Bell, 2007). The prognosis is good to guarded for resolution of paraphimosis, depending on the severity and duration of clinical signs. The owner must be informed that erection and ejaculation in the animal may be impaired after paraphimosis.



Phimosis


Common owner complaints for a patient with phimosis is that their pet may lick its prepuce excessively, may dribble urine from the preputial opening after urination, may suffer from an offensive or hemorrhagic preputial discharge, or may have a fluid-distended prepuce, stranguria, and pollakiuria. The diagnosis is often obvious once attempts are made to extend the penis for examination. In cases in which urine is voided into the preputial cavity, a secondary balanoposthitis may be evident as inflammation (reddening, swelling, and ulceration) of the tissues at the preputial opening. A bacterial culture and sensitivity must be submitted before treating balanoposthitis. Fluid (usually retained urine) may be palpable inside the preputial cavity; this also should be cultured. Other than direct examination, the diagnosis can be made using contrast radiography or ultrasonography. Contrast radiography is accomplished by filling the preputial cavity with saline and then taking radiographs of the penis and prepuce. Ultrasonographic examination largely can achieve the same results as contrast radiography. Ultrasonography allows for the detection of adhesions between the penis and preputial mucosa that were not detected by palpation through the preputial skin (Payan-Carreira and Bessa, 2008).


Symptomatic cases of phimosis require surgical correction. Antimicrobial therapy targeted with sensitivity testing should be initiated 48 to 72 hours before surgery. The simplest corrective surgery involves widening an excessively narrow preputial opening. This can be accomplished by making a longitudinal, full-thickness incision through the dorsal aspect of the preputial ring. Making an incision through the ventral aspect of the preputial opening should be avoided because this results in the persistent exposure of the tip of the penis. In cases in which adhesions are present between the penile and preputial mucosa, the preputial cavity must be exposed through a ventral longitudinal incision in the middle of the prepuce. This allows adhesions to be broken by blunt and sharp dissection. Once separated, the penile and preputial mucosal defects should be closed with absorbable suture material. Leaving the defects open may result in the formation of new adhesions and a recurrence of the problem.


The prognosis for most phimosis cases that have been subjected to corrective surgery is good to excellent with appropriate postsurgical care to prevent self-trauma.

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Jul 18, 2016 | Posted by in PHARMACOLOGY, TOXICOLOGY & THERAPEUTICS | Comments Off on Acquired Nonneoplastic Disorders of the Male External Genitalia

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