Добавил:
shahzodbeknormurodov27@gmail.com Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз: Предмет: Файл:
An Illustrated Guide to Pediatric Urology ( PDFDrive ).pdf
Скачиваний:
18
Добавлен:
27.08.2022
Размер:
49.44 Mб
Скачать

23.3 Etiology

505

 

 

Figs. 23.4 and 23.5 Clinical photograph showing priapism in two children with sickle cell disease

Factors that can contribute to priapism include the following:

Blood disorders including:

Sickle cell anemia

Leukemia

Medications including:

Oral medications used to treat erectile dysfunction, such as sildenafil (Viagra), tadalafil (Cialis) and vardenafil (Levitra)

Drugs injected directly into the penis to treat erectile dysfunction, such as papaverine

Antidepressants, such as fluoxetine (Prozac) and bupropion (Wellbutrin)

Drugs used to treat psychotic disorders, such as risperidone (Risperdal) and olanzapine (Zyprexa)

Anticoagulant, such as warfarin (Coumadin) and heparin

Alcohol and drug abuse (marijuana or cocaine)

Trauma or injury to the genitals, pelvis or the perineum is a cause of nonischemic (high flow) priapism

Other causes of priapism include:

Spinal cord injury

Blood clots

Poisonous venom, such as venom from scorpions or black widow spiders

23.3Etiology

Priapism can be idiopathic or can be secondary to a variety of diseases, conditions, or medications.

In the United States, the most common cause of priapism in the adult population involves agents used to treat erectile dysfunction.

Internationally, most cases are idiopathic.

The most common cause of priapism in the pediatric population is sickle cell disease (SCD), which is responsible for more than 65 % of cases.

Leukemia, trauma, and idiopathic causes are the causes in 10 % of patients.

Pharmacologically induced priapism is the etiology in 5 % of children.

Among the secondary causes of low-flow priapism are the followings:

Sickle cell anemia – One study found that, in unscreened children with SCD, priapism was the first presentation in 0.5 % of cases.

Thalassemia

Dialysis

Vasculitis

Fat embolism (from multiple long-bone fractures or intravenous infusion of lipids as part of total parenteral nutrition)

506

23 Priapism in Children

 

 

PHYSICAL OR PSYCHOLOGICAL STIMULATION

PARASYMPATHETIC SYSTEM

RELEASE OF NITRIC OXIDE

ACTIVATION OF GUANYLATE CYCLASE

GMP

 

cGMP

 

 

 

CELLULAR Ca

EXTRCELLULAR Ca

 

 

 

 

VASODILATATION

 

 

ERECTION

Neurologic diseases that can result in lowflow priapism include the following:

Spinal cord stenosis (i.e. trauma to the medulla)

Autonomic neuropathy and cauda equina compression

Neoplastic disease (metastatic to the penis or obstructive to venous outflow) that can result in low-flow priapism include the following:

Prostate cancer

Bladder cancer (highest risk)

Hematologic cancer (leukemia)

Renal carcinoma

Melanoma

Pharmacologic causes of low-flow priapism include the following:

Intracavernosal agents – Papaverine, phentolamine, prostaglandin E1

Intraurethral pellets (i.e. medicated urethral system for erection with intracavernosal prostaglandin E1)

Antihypertensives – Ganglion-blocking agents (e.g. guanethidine), arterial vasodilators (e.g. hydralazine), alpha-antagonists (e.g. prazosin), calcium channel blockers

Psychotropics – Phenothiazine, butyrophenones (e.g. haloperidol), perphenazine, trazodone, selective serotonin reuptake inhibitors (e.g. fluoxetine, sertraline, citalopram) [3]

Anticoagulants – Heparin, warfarin (during rebound hypercoagulable states)

Recreational drugs – Cocaine

Hormones – Gonadotropin-releasing hormone (GnRH), tamoxifen, testosterone, androstenedione for athletic performance enhancement

Herbal medicine – Ginkgo biloba with concurrent use of antipsychotic agents

Miscellaneousagents–Metoclopramide, omeprazole, penile injection of cocaine, epidural infusion of morphine and bupivacaine

Only rare case reports have associated phosphodiesterase-5 enzyme inhibitors such as sildenafil with priapism. In fact, several reports suggest sildenafil as a means to treat priapism and as a possible means of preventing full-blown episodes in patients with sickle cell disease.

23.4

Classification of Priapism

 

507

 

 

 

• High-flow priapism may result from the fol-

 

corpora cavernosa while the venous

lowing forms of genitourinary trauma:

 

drainage remains normal.

Straddle injury

 

 

 

 

• An adequate arterial flow and well-

– Intracavernous injections resulting in direct

 

oxygenated corpora

 

cavernosal artery injury

 

• The prognosis is better, and secondary

• Rare causes of priapism include the

 

impotence is rare (<20 %).

following:

 

 

 

 

• In children high flow priapism is typi-

– Amyloidosis (massive amyloid infiltration)

 

cally caused by post-traumatic arterio-

– Gout (one case report)

 

cavernosal fistula (from penile, perineal

Carbon monoxide poisoning

 

or pelvic trauma), and generally mani-

Malaria

 

 

 

 

fests several days after the trauma.

– Black widow spider bites

 

• Evidence of blunt or penetrating injury

Asplenia

 

 

 

 

to the penis or perineum especially

Fabry disease (rare association, occasion-

 

straddle injury is usually the initiating

 

ally noted to be priapism of the high-flow

 

event.

 

type)

 

 

 

 

• It can also be caused by:

Vigorous sexual activity

 

– Intracavernosal injections of vasoac-

Mycoplasma pneumoniae infection (mech-

 

tive agents

 

anism is thought to be a hypercoagulable

 

– Scorpion or snake bites

 

state induced by the infection)

 

– Substance abuse (mainly cocaine,

 

 

 

 

 

 

which can cause high or low output

 

 

 

 

 

 

priapism)

23.4

Classification of Priapism

 

 

– Therapeutic drugs (especially psy-

 

 

 

 

 

 

chiatric medications with autonomic

• Priapism is a sustained painful erection of the

 

nervous system effects

penis often nocturnal or starting in the early

 

– Infectious diseases or tumors

hours of the morning.

 

 

• Low flow priapism (ischemic):

• Priapism develops when there is excess arte-

– This is the commonest type

rial inflow to the penis or when there is persis-

– Low flow priapism is characterized by loss

tent venous outflow obstruction to the penis.

 

of vascular regulation.

• Priapism is classified into two main types:

Venous drainage is impaired, presumably

High flow arterial priapism. This is also

 

as a consequence of vascular blockage by

 

called non-ischemic priapism.

 

deformed red blood cells.

– Low flow priapism. This is also called isch-

– This is the classic type seen in patients with

 

emic priapism.

 

 

 

 

SCD where there is stasis leading to

• High flow (non-ischemic) priapism:

 

hypoxia and acidosis of venous blood in a

– This is usually seen following trauma caus-

 

normally erected penis. This will lead to

 

ing injury to the cavernosal artery.

 

sickling of RBCs within the corpora caver-

– This type of priapism is generally not pain-

 

nosa venous sinusoids, venous outflow

 

ful and may manifest in an episodic

 

obstruction and engorgement of the cor-

 

manner.

 

 

 

 

pora cavernosa. The corpora spongiosa and

The penis in high flow priapism is neither

 

glans of the penis are spared.

 

fully rigid nor painful and does not require

The corpora cavernosa becomes rigid and

 

an emergency treatment.

 

tender to palpation.

Characteristics

of

high-flow priapism

This may be further complicated as the

 

include the following:

 

fixed resistance maintained by the adventi-

 

• High flow priapism is characterized by

 

tia of the corpora cavernosa causes a com-

 

an increase

of

arterial supply to the

 

partment syndrome.

508

23 Priapism in Children

 

 

Low-flow priapism is generally painful, although the pain may disappear with prolonged priapism.

Characteristic features of low-flow priapism include the following:

Rigid erection

Ischemic corpora as indicated by dark blood upon corporeal aspiration

No evidence of trauma

Low flow priapism is considered a medical and surgical emergency and priapism should be resolved within 6 h of the onset of the episode to minimize the sequelae.

In addition to SCD, low flow priapism can be caused other hematologic diseases with hypercoagulability or hyperviscosity such as leukemia’s and several drugs.

It is important to differentiate between these two types as the management and prognosis are different.

The two types of priapism can be differentiated using color duplex Doppler ultrasonography and analysis of blood aspirated from the corpora cavernosa.

Color Doppler ultrasonography measures blood flow. This typically show little or no blood flow in the cavernosal arteries in those with low flow priapism.

Analysis of blood aspirated from the corpora cavernosa is done at the time of aspiration and irrigation.

In patients with high flow priapism, the aspirated blood:

Is bright red

• Has a pO2 >90 % mmHg, pCO2 <40 mmHg and a pH of approximately 7.40.

In patients with low flow priapism, the aspirated blood:

Is dark in color

Has a pO2 <30 mmHg, pCO2 >60 mmHg and a pH <7.25.

Priapism is also classified into two types:

Stuttering priapism: This lasts 2–4 h, often recurrent and may precede a severe attack.

Acute (Severe) priapism: This lasts longer than 4 h and can result in impotence.

23.5Clinical Features

Priapism causes abnormally persistent erections not related to sexual stimulation.

Priapism symptoms may vary depending on the type of priapism.

There are two main types of priapism: ischemic and nonischemic priapism.

Ischemic priapism:

Ischemic, also called low-flow, priapism is the result of blood stasis in the penis.

It’s the more common type of priapism.

Low-flow, ischemic-type priapism is generally painful, although the pain may disappear with prolonged priapism.

It is characterized by ischemic corpora, as indicated by dark blood upon corporeal aspiration; and no evidence of trauma

The history may reveal an underlying cause

Stuttering priapism is unwanted erection off and on for several hours.

Signs and symptoms include:

Unwanted erection lasting more than 4 h

It is characterized by a rigid, painful erection

Rigid penile shaft, but usually soft glans of penis

Usually painful or tender penis

Nonischemic priapism:

Nonischemic, or high-flow, priapism occurs when too much blood flows into the penis.

This type of priapism is associated with blunt or penetrating injury to the perineum. It may manifest in an episodic manner.

Nonischemic priapism is usually painless.

Signs and symptoms include:

Unwanted erection lasting at least 4 h

Erect but not rigid penile shaft

Patients with high-flow priapism typically have a history of blunt or penetrating trauma to the penis or perineum, resulting in a fistula between a cavernosal artery and the corpus cavernosum.

Clinically, high-flow priapism is characterized by a painless erection; tumescence is typically less marked than in low-flow priapism.