23.6 Investigations

•The presence of bright red blood during aspiration is a helpful but not pathognomonic finding of high-flow priapism.

•Penile blood gases findings approximate normal arterial values.

•Penile duplex ultrasonography with angiographic confirmation helps to identify and locate these fistulae.

•Patients with priapism report a persistent erection.

•The physical examination detects an erection restricted to the corpora cavernosa. The spongiosum and the glans remain flaccid, except for the rare cases of tricorporal priapism.

•Because of the lack of involvement of the periurethral spongiosum, there are normally no micturating problems.

•Accompanying symptoms depend on the type of priapism and the duration of engorgement.

•Penile priapism generally involves only the paired corpora cavernosa, with the glans and corpora spongiosum remaining flaccid or softly distended without rigidity.

•In high flow priapism the erection is less rigid and the penis is pink and pulsatile.

•There can be signs of trauma (hematomas, bruises).

•It may be possible to resolve the erection compressing the arteriovenous fistula feeder vessel, but the erection will recur immediately after the compression is withdrawn.

•In low flow priapism the penis is rigid, extremely painful and seems ischemic: it does not pulse, is pale or grayish and cold. These manifestations are more evident after the episode has evolved for at least 4 h.

•In young children, the presence of the Piesis sign (prompt detumescence upon perineal compression with the examiner’s thumb) indicates high-flow priapism.

•To provide appropriate treatment, physicians must differentiate between low-flow and highflow priapism. This is accomplished by taking a thorough history, performing a careful physical examination, and measuring the oxygen content of blood within the corpora cavernosa by penile blood gas analysis.

23.6Investigations

•A complete blood cell count (CBC) should be performed to determine whether the patient has anemia, leukocytosis, or thrombocytosis.

•Patients with sickle cell disease should have a CBC and a reticulocyte count.

•If sickle cell status is unknown, a hemoglobin electrophoresis should be done.

•Patients with sickle cell disease may also need a blood type and screen performed in case blood transfusion or exchange is necessary.

•Urinalysis and urine culture

•Measurement of plasma thromboplastin or activated partial thromboplastin time to determine coagulation status may be useful, as priapism may require surgical intervention if medical treatment fails.

•Penile blood gas results allow differentiation between highand low-flow priapism.

–Low-flow priapism, penile blood gases findings:

•The blood will be dark

•Acidotic (pH <7.0)

•Hypercarbonic (PCO >60 mmHg)

•Hypoxemic (PO2 <30 mmHg)

•Variations in these values depend on the duration of priapism.

–High-flow priapism penile blood gases findings:

•The blood will be red

•Alkalotic (pH >7.0)

•Normally oxygenated (pO2 >60 mmHg)

•pCO2 <70 mmHg

•Color-flow penile Doppler imaging is currently the study of choice to differentiate highflow from low-flow priapism. In patients with high-flow priapism, ultrasonography can help identify and locate fistulas.

•In patients with high-flow priapism, selective penile angiography may be required in order to identify the site of the fistula, or to confirm the location of a fistula identified by ultrasound. The fistula can then be closed by embolization.

•Perform chest radiography or computed tomography (CT) scanning if the history is consistent with a malignant or metastatic condition.

•Use of scintigraphy has been proposed to differentiate low (decreased uptake, “cold” CC) from high flow cases, but the limited availability of the test, its low specificity and sensitivity and the lack of a comparative or gold standard has limited its use.

•Doppler ultrasound is more useful for high flow cases, to identify an arteriovenous fistula supplying the erection.

•Cavernosography is rarely used, because blood analysis is adequate and less aggressive.

•Arteriography of the internal pudendal artery has some limited use in high flow cases in which there is an intention to treat by embolization or surgery.

23.7Management

•Appropriate treatment of priapism varies, depending on whether the patient has lowflow or high-flow priapism.

•Most priapism cases are the low-flow ischemic type.

•Treatment of low-flow priapism should progress in a stepwise fashion, starting with therapeutic aspiration, with or without irrigation, or intracavernous injection of a sympathomimetic agent.

•Treatment of high-flow priapism focuses on identification and obliteration of fistulas.

•In patients with priapism secondary to other disorders, attempt to treat the underlying condition whenever possible.

•Treatment for priapism secondary to sickle cell disease includes hydration, alkalization, analgesia, and oxygenation to prevent further sickling. Hypertransfusion and/or exchange transfusions may be required to increase hemoglobin concentration to higher than 10 % and decrease hemoglobin S to less than 30 %.

•At least 50 % of patients with priapism have persistent impotence, either because of the priapism event or its treatment.

•The European Association of Urology guidelines on the diagnosis and treatment of priapism include:

–Interventions for ischemic priapism, which is an emergency condition, should begin within 4–6 h and include decompression of the corpora cavernosa by aspiration and intracavernous injection of sympathomimetic drugs

–When conservative management for ischemic priapism fails, surgical treatment is recommended

–For patients with long-lasting priapism, immediate implantation of a prosthesis should be considered

–For arterial priapism, which is not an emergency, selective embolization has high success rates

–The main therapeutic goal for stuttering priapism is prevention of future episodes, which may be achieved pharmacologically (although information on the efficacy of such treatment is limited)

–Prehospital Care

•Prehospital Care:

–Any patient who has an erection for longer than 4 h, especially if he has a predisposing illness (e.g., sickle cell disease) should receive therapy for priapism

–Most cases, if seen early enough in their course, respond to conservative measures.

•The use of ice packs to the perineum and penis

•Ask the patient to walk upstairs. The latter strategy is thought to work via an arterial steal phenomenon.

•External perineal compression may also be a useful temporizing measure.

•Low-Flow Priapism

–Treatment should progress in a stepwise fashion, accompanied by supportive care and the identification and treatment of reversible causes.

–Intracavernosal phenylephrine (NeoSynephrine) is the drug of choice and firstline treatment of low-flow priapism

because the drug has almost pure alphaagonist effects and minimal beta activity.

–In short-term priapism (<6 h), especially drug-induced cases, intracavernosal injection of phenylephrine alone may result in detumescence.

–Some studies suggest that terbutaline orally, at a dose of 5–10 mg, followed by another 5–10 mg 15 min later, if required, produces resolution in about one third of patients.

–Oral pseudoephedrine, 60–120 mg orally has also been suggested as a potential therapy due to its alpha-agonist effect. The exact efficacy of this medication orally is unknown.

–Oral medications may be a reasonable treatment option to use while preparing for aspiration/injection. If no resolution occurs within 30 min, injection therapy is required.

–Aspiration/injection of the corpus cavernosum:

•First perform a penile nerve block.

•Inject around the entire base of the penile shaft with 1 % lidocaine without epinephrine or bupivacaine without epinephrine.

•Providing anesthesia will increase patient comfort and improve patient cooperation with the sometimes-painful penile aspiration procedure.

•After anesthesia is ensured, use a 19-gauge needle attached to a large syringe to puncture the corpus cavernosum. The needle should be inserted through the shaft of the penis laterally to avoid the corpus spongiosum and urethra ventrally and the neurovascular bundle dorsally.

•Aspirate 20–30 mL of blood from either the 2-o’clock or 10-o’clock position while milking the shaft.

•Aspiration may be difficult because of the sluggish blood within the corpus cavernosum.

•Saline irrigation and repeated aspirations may improve flow dynamics.

•Because multiple communications exist from one corpus to the other, aspiration usually is required on one side only.

•If initial aspiration of the corpus cavernosum reveals bright red blood rather than dark venous blood, consider an arterial cause for priapism and treat as for high-flow cases.

•Aspiration alone has a success rate of around 30 %.

•If this procedure is not successful, phenylephrine, epinephrine, or methylene blue may be instilled into the corpus cavernosa.

•For the injection, use a mixture of 1 ampule of phenylephrine (1 mL: 1,000 mcg) and dilute it with an additional 9 mL of normal saline.

•Using a 29-gauge needle, inject 0.3– 0.5 mL into the corpora cavernosa, waiting 10–15 min between injections.

•Monitor vital signs and apply compression to the area of injection to help prevent hematoma formation.

•If phenylephrine is not available, epinephrine can be used. However, epinephrine has more adverse effects and is considered second-line treatment. Another second-line treatment is instillation of methylene blue.

•Alternatively, the corpora cavernosa can be irrigated with a diluted solution of phenylephrine. A diluted solution can be infused 10–20 mL at a time.

•If aspiration or injection is successful in producing detumescence, place an elastic bandage around the shaft of the penis to ensure continued emptying of the corpora and to compress the puncture site.

•High-Flow Priapism:

–Acutely, observation alone may be sufficient for high-flow priapism, because many cases resolve spontaneously, and even with prolonged priapism these patients are unlikely to experience significant pathological damage or impaired erectile function.

–Compression therapy may be successful in certain cases, especially children; continuous compression may be maintained with a strap-on dressing.

–Selective angiography with subsequent embolization of the offending vessel has been shown to be effective with few longterm complications in some studies.

–Selective arterial embolization can be done using autologous blood clot, gelatin sponge, microcoils, or chemicals.

–Patients who do not respond to more conservative measures may benefit from this approach.

–Surgical ligation of the fistula may be required. However, potential complications of this procedure include long-term impotence.

•Surgical Care:

–A transglanular-to-corpus cavernosal scalpel or needle-core biopsy (Ebbehoj or Winter technique) is the first reasonable approach for refractory priapism.

–A unilateral shunt is often effective.

–Bilateral shunts are used only if necessary (usually apparent after 10 min).

–The El-Ghorab procedure is a more aggressive open surgical cavernosal shunt and is indicated if the Winter shunt fails.

–Quackel shunts are cavernosal-spongiosum shunts (unilateral or bilateral) and are performed via a perineal approach. Such shunts are rarely effective if a more distal shunt has already failed (e.g., El-Ghorab procedure) because thrombosis of the corpora is usually already present.

–A Grayhack shunt is a cavernosalsaphenous vein shunt (rarely necessary or indicated). Proximal cavernosal-saphenous shunt (Grayhack shunt) surgically connects the proximal corpora cavernosum to the saphenous vein.

–Prolonged low-flow priapism results in a variable degree of cavernosal fibrosis and a subsequent loss of penile length.

–The delayed insertion of a penile prosthesis can be difficult, with high complication rates.

–Immediate insertion of a penile prosthesis in patients with prolonged low-flow priapism is simple and maintains penile length. This may be offered to patients at initial presentation, as the complication rate is low and the subsequent outcome excellent.

23.8Prognosis

•The prognosis depends on the duration of symptoms, the patient’s age, and the underlying pathology.

•The duration of symptoms is the single most important factor affecting outcome.

•A Scandinavian study reported that 92 % of patients with priapism for less than 24 h remained potent, while only 22 % of patients with priapism that lasted longer than 7 days remained potent.

•All patients with priapism should be warned about the long-term risk of erectile dysfunction.

•In general, low flow (ischemic) priapism poses a higher risk of impotence than high-flow arterial priapism.

•Sickle cell disease patients appears to be particularly at increased risk.

•A study by Anele and Burnett found that patients with sickle cell disease who experience even minor episodes of recurrent ischemic priapism are five times more likely to develop erectile dysfunction compared with non–sickle cell patients.

•Infection can complicate priapism.

•Patients must understand that a poor outcome is possible despite appropriate and timely management.

•Stuttering priapism requires careful counselling for episodic management.

•Chronic prophylaxis may be obtained using α-adrenergic sympathomimetics, phosphodi-

esterase type 5 inhibitors and, in sickle cell disease, hydroxyurea.