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Priapism

Last updated: October 21, 2020

Summary

Priapism refers to a sustained erection that lasts for more than four hours and is not the result of sexual excitation. Based on etiopathogenesis, priapism may be classified as either low-flow or high-flow. Low-flow priapism, which is caused by inadequate venous outflow from the corpus cavernosum, results in painful penile ischemia. Low-flow priapism in adults most commonly arises as an adverse effect from treating erectile dysfunction (e.g., sildenafil), while sickle cell disease is the most common cause in children. High-flow priapism is less common and usually the result of perineal trauma. High-flow priapism is not associated with penile ischemia and is therefore painless. Penile blood gas analysis and doppler ultrasound of the penis allow high-flow priapism to be distinguished from low-flow priapism. Low-flow priapism is an acute urological emergency that must be treated within 12 hours; treatment involves aspiration of blood from the corpus cavernosum and injection of phenylephrine. If priapism does not subside, surgical therapy to decompress the penis is indicated. When treated within 12 hours, complete restoration of erectile function is possible; delayed treatment leads to cavernous fibrosis and irreparable damage with erectile dysfunction. Non‑ischemic priapism usually does not require treatment.

Definition

  • A sustained erection that lasts more than 4 hours, is not caused by sexual excitation and is not relieved by ejaculation. [1]

Epidemiology

  • Priapism can affect individuals of all age groups but two peaks are observed at 5–10 years and 20–50 years. [2][3]
  • Race: no racial predilection
  • Sex: Priapism is almost exclusively a male disease (very rarely clitoral priapism may occur). [4]

Epidemiological data refers to the US, unless otherwise specified.

Low-flow priapism (ischemic priapism)

Medication (especially for erectile dysfunction) is the most common cause of low-flow priapism among adults. Among children, sickle cell disease is the most common cause of low-flow priapism.

Low-flow priapism is a urological emergency. Treatment of low-flow priapism within 12 hours is crucial because delayed treatment may result in permanent damage (cavernous body fibrosis with irreversible erectile dysfunction)!

High-flow priapism (nonischemic priapism)

  • Occurrence: less common than low-flow priapism [8]
  • Etiology [5]
  • Pathophysiology
    • Excessive arterial influx with sufficient venous outflow
    • No penile ischemia
  • Clinical features [6]
    • There is up to a 72-hour delay between the initial injury and the onset of priapism.
    • Not painful
    • The corpus cavernosum is not completely rigid.
    • Symptoms of perineal trauma: perineal swelling, hematuria, dysuria
  • Diagnostics: See “Diagnostics” below.
  • Treatment [6]
  • Prognosis: has a good prognosis, with most cases resolving spontaneously.

Diagnostics

One or both of the following tests are used to differentiate high-flow from low-flow priapism: [6]

References

  1. Williams NS, Bulstrode C, O'Connell PR. Bailey & Love's Short Practice of Surgery. CRC Press ; 2013
  2. Cherian J, Rao AR, Thwaini A, Kapasi F, Shergill IS, Samman R. Medical and surgical management of priapism.. Postgrad Med J. 2006; 82 (964): p.89-94. doi: 10.1136/pgmj.2005.037291 . | Open in Read by QxMD
  3. Burnett AL. Nitric oxide in the penis--science and therapeutic implications from erectile dysfunction to priapism.. J Sex Med. 2006; 3 (4): p.578-582. doi: 10.1111/j.1743-6109.2006.00270.x . | Open in Read by QxMD
  4. Medina CA. Clitoral priapism: a rare condition presenting as a cause of vulvar pain.. Obstet Gynecol. 2002; 100 (5 Pt 2): p.1089-91. doi: 10.1016/s0029-7844(02)02084-7 . | Open in Read by QxMD
  5. Montague DK, Jarow J, Broderick GA et al. Priapism. J Urol. 2003; 170 (4 Pt 1): p.1318-1324. doi: 10.1097/01.ju.0000087608.07371.ca . | Open in Read by QxMD
  6. Kasper DL, Fauci AS, Hauser S, Longo D, Jameson LJ, Loscalzo J . Harrisons Principles of Internal Medicine . McGraw-Hill Medical Publishing Division ; 2016
  7. Pryor JP, Hehir M. The management of priapism.. Br J Urol. 1982; 54 (6): p.751-4. doi: 10.1111/j.1464-410x.1982.tb13641.x . | Open in Read by QxMD
  8. Kim KR. Embolization Treatment of High-Flow Priapism.. Seminars in interventional radiology. 2016; 33 (3): p.177-81. doi: 10.1055/s-0036-1586152 . | Open in Read by QxMD