Priapism in a stallion with generalized malignant melanoma

A Thoroughbred stallion developed priapism that was unresponsive to medical treatment and lavage of the corpus cavernosum penis with heparinized 0.9% NaCl solution. Three weeks after onset of priapism, the penis was firm and noncompliant, and penile pain sensation and ability to retract the penis were lost. Ultrasonography confirmed thrombosis of the corpus cavernosum penis. The stallion was euthanatized because of poor prognosis for return to breeding soundness. Necropsy revealed enlargement of numerous lymph nodes. The dorsal penile nerves were demyelinated distal to the crura of the penis. A diagnosis of generalized malignant melanoma was made; however, neither metastasis to the vertebral canal nor compression of spinal nerve roots as they exited the vertebral foramen was found. Priapism is a persistent erection without sexual arousal and is initially unassociated with penile paralysis, but if prolonged, leads to irreversible venous occlusion where collecting veins join the cavernous spaces. Damage to the dorsal penile nerves may explain the long-term penile paralysis and loss of sensation that accompanied priapism in this stallion. Priapism unassociated with the use of phenothiazine-derivative tranquilizers is uncommon in horses.     

Surgical Treatment of Priapism in a Stallion

Priapism occurred in a stallion after the administration of acetylpromazine. When conservative measures failed, the corpus cavernosum penis (CCP) was drained and irrigated, and a vascular shunt between the erectile bodies was created. Subsidence of erection resulted, but subsequently, the stallion was unable to retract or erect the penis. The stallion was castrated and the penis was surgically retracted into the sheath.     

Priapism after castration in a cat

Priapism developed in a cat 2 days after castration and strangury. The priapism was unresponsive to massage and antimicrobial treatment. Because of penile engorgement and necrosis, a perineal urethrostomy was performed. Clinical signs of priapism resolved after urethrostomy. Histologic examination of tissues revealed vascular stasis within the corpus cavernosum penis and funiculitis of the right spermatic cord.     

The effect of a surgically created shunt between the corpus cavernosum penis and corpus spongiosum penis of stallions on erectile and ejaculatory function

OBJECTIVE: To evaluate the effect of a shunt created between the corpus cavernosum penis (CCP) and corpus spongiosum penis (CSP) on erectile and ejaculatory function of normal stallions and to verify persistence of the shunt. STUDY DESIGN: The capability of stallions to develop an erection and to ejaculate was evaluated before and after creation of a corporeal shunt. Persistence of the shunt was determined by dye injection into the CCP at necropsy. ANIMALS: Six stallions. METHODS: A CCP-CSP shunt was created in five stallions. Semen was collected before and 4 to 14 weeks after surgery, before the horses were euthanatized. Dye was injected into the CCP to determine persistence of the shunt. Dye was also injected into the CCP of a control stallion. RESULTS: All stallions had normal erectile and ejaculatory function before and after surgery. Dye, injected into the CCP, entered the CSP in three of five treated stallions, demonstrating persistence of the shunt, whereas in two stallions, dye was found only in the CCP, indicating closure of the shunt. No dye was detected in the CSP of the control stallion. CONCLUSIONS: Creation of a corporeal shunt does not interfere with normal erection and ejaculation of stallions. Shunt closure is not necessary for stallions to retain normal erectile and ejaculatory function. CLINICAL RELEVANCE: Failure of a stallion affected by priapism to achieve normal erection or to ejaculate after creation of a corporeal shunt would likely be because of damage to corporeal tissue than from an effect of the shunt.     

Treatment of Intraoperative Persistent Penile Erection in a Stallion

This case report describes the occurrence of persistent penile erection in a breeding stallion that occurred while the horse was under inhalant anesthesia for a carpal arthroscopy. The horse had no history of breeding problems, and no abnormalities were detected on physical examination, complete blood count, or serum chemistry tests performed prior to surgery. Anesthesia was induced with guaifenesin and ketamine after sedation with xylazine and was maintained with isoflurane in 100% oxygen. Penile erection developed approximately 35 minutes after induction and persisted for over 2 hours despite various physical and pharmacological attempts to alleviate it (massage, cold compresses, intravenous benztropine administration, and intracavernosal phenylephrine). Successful resolution of the erection was obtained by cannulation and drainage of blood from the corpus cavernosum and subsequent irrigation with heparinized sterile saline and infusion of phenylephrine in the corpus cavernosum. The detumescent penis was placed back into the sheath, and purse string sutures were placed in the sheath to ensure the penis would remain inside the sheath during recovery. The stallion's recovery from anesthesia was uneventful, the sutures were removed, and the horse was fitted with a penile sling to prevent additional edema or trauma. The stallion recovered completely from the persistent penile erection. Semen was collected 6 days after the event, and he returned to normal pasture breeding 6 weeks after surgery.     

Cavernosography and differential diagnosis of impotence in the bull

A new indirect radiographic technique is described for the differential diagnosis of erectile impotence in the bull. Two cases of impotence have been investigated in this way. In the first, occlusion of the dorsal longitudinal canal of the corpus cavernosum penis in an 18-month-old Hereford bull was diagnosed. In the second, distal venous drainage of the corpus cavernosum penis was demonstrated in a five-year-old Hereford bull. Post mortem examination of the reproductive tract confirmed the diagnosis in each case.     

Impotence in bulls due to vascular shunts from the corpus cavernosum penis

Eleven bulls were determined to be impotent due to vascular shunts from the corpus cavernosum penis to the extracorporeal circulation. Clinically, the bulls were unable to achieve erection when stimulated with an electroejaculator and in natural breeding trials. The vascular shunts were located by serial contrast radiography of the corpus cavernosum penis. Surgical correction of the shunts was attempted in 8 of the bulls by wedge resection of the tunica albuginea. In 4 bulls, the surgical correction was successful and the bulls were returned to service.     

Angiography of the crus penis in the ram and buck during erection

Serial angiography was used to determine blood flow patterns to the penis of rams and bucks. Animals were anesthetized and the internal pudendal artery was catheterized so that contrast medium could be injected toward the crus penis area. By comparing vascular patterns of the ram and buck during erection, it was found that flow patterns of the corpus cavernosum penis (CCP) and corpus spongiosum penis (CSP) were similar for both species. Contraction of the ischiocavernosus muscles occluded the arterial inflow and venous outflow to the CCP, making it a closed system during peak erection. However, during erection, the contrast medium continued to flow into the CSP, showing that it is not a closed system. In the vasodilatation phase, the CSP usually filled before and more intensely than did the CCP.     

Urethral Defects in Geldings With Hematuria and Stallions With Hemospermia

A urethral defect, presumed to communicate with the corpus spongiosum penis, caused hematuria in seven geldings and hemospermia in three stallions. Hematuria in geldings occurred at the end of urination. Hematuria was not observed in stallions with hemospermia. A linear urethral defect was identified, by endoscopic examination, on the convex surface the urethra at the level of the ischial arch of each horse. Cause of the defect was not determined. Two stallions were successfully treated for hemospermia, one by temporary subischial urethrostomy combined with sexual rest for 10 weeks, and the other by sexual rest alone for 6 months. The third stallion had hemospermia 6 weeks after urethrostomy. The geldings were successfully treated for hematuria, six by temporary subischial urethrostomy, and one by a subischial incision that extended into the corpus spongiosum penis but did not enter the lumen of the urethra. Efficacy of subischial urethrostomy for treatment of hemospermia was difficult to assess because of the small number of surgically treated stallions. In geldings, surgery eliminated hematuria, presumably by reducing vascular pressure in the corpus spongiosum penis during urination, thus allowing the urethral defect to heal.     

Surgical repair of urethral transection in a horse

A recently castrated horse was examined because of preputial and ventral abdominal swelling, prolapse of the preputial fold, and serosanguinous fluid dripping from the external urethral orifice. After a poor response to initial medical management, a urethral laceration was found during exploratory surgery. Half of the ventral portion of the corpus cavernosum penis had been transected. Primary closure was followed by healing without complications.     

Arterial supply of the penis in the New Zealand rabbit (Oryctolagus cuniculus L.)

In the present study, the distributional pattern of the penile artery and the vessels joining the blood supply of the penis were investigated in the New Zealand rabbit. Eight adult rabbits were used in the study. In order to exhibit the vascular network by dissection, latex was injected via the abdominal aorta. The main vessel which supplies blood to the penis, the penile artery, is a branch of the internal pudendal artery. It divides into two branches which form the deep and dorsal penile arteries at the level of the ischiadic arch. The deep penile artery penetrates the tunica albuginea, and forms the arterial network of corpus cavernosum penis. On the other hand, the dorsal penile artery gives off three small branches for the subischiocavernosus muscle and at the level of the attachment of this muscle sends two small branches for the preputium. The course of both arteries follows the dorsolateral surface of the penis to the glans and ends in an anastomosis. Hence, a caudal branch of the prostatic artery which originates from the umbilical artery joins the blood supply of the penis in the rabbit. After vascularizing the prostate complex, it ends by entering the corpus spongiosus penis at the dorsolateral surface at the level of the ischiadic arch.     

Venous drainage of the bovine corpus cavernosum penis in relationship to penile dimensions and age

The veins of the corpus cavernosum penis (ccp) were examined in 34 calves aged one to three weeks, 38 calves aged three to four months, five bulls aged 10 to 14 months and six bulls aged two-and-a-half to five-and-a-half years. Shortly after birth, the cavernous spaces of the ccp within the body of the penis drain into the dorsal venous system. The veins increase in size up to three to four months old, but by 10 to 14 months they have regressed markedly, both in numbers and in size. In normal bulls, over two-and-a-half years, there is no venous drainage of the ccp within the body of the penis. The thickness of the tunica albuginea does not seem important in determining the location of the veins that traverse it to drain the ccp or in facilitating the development of venous drainage during the first three or four months of post natal life. These findings are discussed in relation to impotence associated with distal venous drainage of the ccp in young and adult bulls.     

The microvascularization of the penis of the steer (Bos taurus)]

The blood supply and the microvascularization of the bovine penis (Bos taurus) were demonstrated using the scanning electron microscope. The Corpus cavernosum penis of the bull consists of a surprisingly well-developed mesh of small to intermediate vessels. The architecture of the cavernous body is largely determined by trabeculae of connective tissue, the extent of which varies between penis segments. The Corpus cavernosum is arranged primarily as a ring around the trabeculae of connective tissue. Chambers of large bore are found in the central portions of the Corpus cavernosum penis, whereas a relatively fine vascular network predominates in the periphery. Vessels in the cavernous body of the urethra, on the other hand, show strictly parallel orientation to the urethra, which they surround like a sleeve. They also stand in close association with vessels in the outer layer of the Tunica albuginea. The vascular systems of the Corpus cavernosum penis and the Corpus spongiosum penis are not connected with one another. The vascular architecture of the Glans penis is characterized by the inclusion of well-developed vascular arcades at regular intervals. These course through a connective tissue matrix rich in glycoproteins and stretch to just under the skin of the penis, where they are intimately associated with a subpapillary network of arteries and veins. The venous legs of the vascular arcades are supplied by this network of veins. The Glans penis of the bull is considered to represent a specialization of the penile integument.     

Perineal incision into the corpus spongiosum penis to resolve persistent post urination haemorrhage after partial phallectomy

Partial phallectomy or en bloc resection are surgical methods to address pathological conditions of the penis and/or prepuce including neoplasia, trauma, habronemiasis, chronic paraphimosis or permanent penile paralysis, and priapism. Haemorrhage associated with urination is a common complication observed after penile surgery but usually resolves spontaneously without specific treatment. This report describes a case of post urination haemorrhage (PUH) that recurred with each urination and persisted without significant improvement for a period of 2 weeks following en bloc resection of the penis and the prepuce. A perineal incision (PI) into the corpus spongiosum of the penis (CSP) resolved PUH by decreasing the blood pressure in the CSP distal to the PI. We propose that PI of the CSP can be an effective method to address PUH after penile surgery and may decrease time of hospitalisation for horses affected with PUH after phallectomy procedures.     

Penile haemangiosarcoma in a breeding stallion

A 9‐year‐old Arab stallion was presented for haematuria and a haemorrhagic mass on the urethral process of the penis. Clinical examination and surgical excision suggested a tumour of the penis, histologically confirmed as a haemangiosarcoma. The stallion was successfully treated with surgical excision; however, successful breeding has not been achieved thus far (28 months). To the authors' knowledge, haemangiosarcoma of the equine penis has not previously been described.     

Perianesthetic development of diaphragmatic hernia in a horse with equine pituitary pars intermedia dysfunction (PPID)

A 21-year-old Thoroughbred gelding with a history of equine pituitary pars intermedia dysfunction (PPID) presented with priapism of 2 days’ duration. The horse received a caudal morphine epidural and then underwent corpus cavernosum lavage and phallectomy under general anesthesia. The patient’s recovery featured multiple unsuccessful attempts to stand and his respiratory distress persisted for several hours until he acutely developed severe colic and was euthanized. Necropsy findings revealed a pituitary adenoma of the pars intermedia, bilateral adrenal cortical hyperplasia, and diaphragmatic herniation. This report suggests that horses with PPID may present a greater risk for diaphragmatic hernia under general anesthesia or during procedures placing stress on the diaphragm, including anesthetic recovery.     

Hematochezia in an African spurred tortoise (Centrochelys sulcata)

An African spurred tortoise (Centrochelys sulcata) that had been housed with a conspecific was presented for tenesmus, diarrhea, and hematochezia of 48 hr duration. Husbandry was considered substandard. Hematology and plasma biochemical analysis revealed dehydration. Urinalysis was considered normal and fecal examination was negative for parasitic ova and protozoa. Radiography demonstrated moderate constipation. Initial treatment consisted of fluid therapy, enrofloxacin, metoclopramide, and improvement of husbandry practices. Recurrence of hematochezia developed 2 wk after initial presentation. Cloacoscopy followed by manual exteriorization of the penis revealed a puncture wound on the dorsal surface of the corpus cavernosum proximal to the glans penis. The wound was sutured using an absorbable monofilament material. The tortoise recovered uneventfully and was asymptomatic for the following 6 mo.     

Arterial supply of the penis in agoutis (Dasyprocta prymnolpha, Wagler, 1831)

The arterial vascularization of agoutis’ penis (Dasyprocta prymnolopha) were analysed using ten male adults from ‘Núcleo de Estudos e Preservação de Animais Silvestres da Universidade Federal do Piauí’ (FUFPI/IBAMA n° 02/99). Among the total number of specimens, six animals had natural death and were members of the research collection of the Laboratory of Anatomy, and four were killed after anaesthesia. Stained bi‐centrifugated‐Cis‐I‐4 latex was injected in arterial vessels responsible for penis vascularization throughout the abdominal portion of aorta. The samples were fixed in 10% formaldehyde solution and arteries were dissected. The penile artery is originated as a branch of internal pudendal artery. At the level of ischiatic arch, the penile artery project two branches, the penile dorsal and the deep arteries; those arteries irrigates the penile dorsal surface and the corpus cavernosum penis. The penile dorsal arteries have an independent course up to the glans penis. Based on the conditions of this work a remarkable similarity regarding the distribution of vessels destined to the agouti penis when compared to other domestic, wild and lagomorph rodents as rabbits.     

Arginase alteration in the reproductive system of alloxan-diabetic dogs

This study was conducted to evaluate possible alteration in the activity of arginase, an important enzyme of cell proliferation and vascular smooth muscle contraction regulator in diabetics, that may be correlated with low fertility in diabetic patients. In this investigation, 6 apparently healthy adult male dogs were selected and divided in two groups, diabetics and non-diabetics. Diabetes mellitus was induced in one group by intravenous (IV) injection of alloxan (100 mg/kg). Dogs with a fasting blood glucose (FBS) of more than 200 mg/dl were considered to be diabetic. Four weeks following induction of diabetes mellitus, the animals in both groups were anesthetized by an IV injection of sodium thiopental. Livers and whole reproductive systems, including the testes, penis, urethra, and prostate, were dissected. The epididymides, corpus cavernosum, corpus spongiosum, penile urethra, and vas deferens were also dissected and removed from the reproductive system. Arginase activity and total protein were measured by the urea and Lowry's methods respectively in above mentioned sections. Plasma testosterone was determined by the radioimmunoassay method. The results showed significantly (P<0.05) increased arginase specific activity (ASA) in the liver, epididymis, prostate, corpus cavernosum and corpus spongiosum of the diabetic dogs. In the reproductive system of the diabetic dog, the maximum and minimum ASA was seen in the corpus cavernosum and testes, respectively (105.12 +/- 8.76 vs. 25.0 +/- 0.55). No such variation was observed in the ASA of normal dogs (39.0 +/- 5.47 vs. 25.0 +/- 5.47). There was no significant difference in plasma testosterone level between the groups. In conclusion, diabetes increased the ASA in liver, prostate, epididymis, corpora cavernosa, and corpora spongiosum of the male dogs and may contribute to erectile dysfunction or low fertility in diabetics.     

Clinical, cytogenetic and hormonal findings in a stallion with hypospadias--a case report

This case report describes a three-year-old Friesian stallion with hypospadias. Physical examination revealed a ventrocaudal deviation of the shaft of the penis and an incomplete glans penis. The urethral opening was 4 cm in length, slit-like and had a mucous membrane covering. A short fold ran from the ventral aspect of the anus and ended with a non-pigmented hairless area of skin. A human choriongonadotropin (hCG)-stimulation test resulted in an increase in the plasma levels of estrogen sulfate and testosterone, indistinguishable from that of a normal stallion. The karyogram had a normal number of chromosomes at 2n=64. The stallion was castrated, and histological evaluation of the testicular tissue was unremarkable. In contrast to other animal species and human beings, hypospadias is a rare congenital abnormality in stallions, the cause of which could not be elucidated in our patient.