What Causes Priapsim?

Patient Presentation
A 11-year-old white male came to emergency room after he disclosed that he had had intermittent priapism for 3 days.
Today, he has had continued priapism for several hours continuously. He denies trauma, medication or masturbation. He has not urinated for several hours.
The past medical history was negative.
The family history was positive for early cardiac disease.
The review of systems was negative including fever, chills, night sweats, weight loss, or medication use. He says he noticed a rash on his body today, but no other bleeding.
The pertinent physical exam showed a school age boy who was in distress secondary to pain. His vital signs showed a slightly elevated heart rate and blood pressure and growth parameters in the 25-75%.
He had petechiae on his face, neck and trunk below the nipple line. He had two bruises on the shins which are healing. HEENT had slightly pale conjunctiva. His cardiac examination reveals tachycardia with a grade I-II systolic murmur best at the lower left sternal border.
Lungs were negative but his abdomen had a liver edge that is 3 cm below the costal margin. The spleen was not palpable. Genitourinary examination revealed a circumcised male with bilateral testes in the scrotum. He has no pain on testicular examination and no inguinal hernia. He has an erect penis, that is swollen and deep red in color that is painful to examine.
He had several 0.5-1.0 cm lymph nodes in the anterior cervical chain and in the inguinal area.
The laboratory evaluation included a complete blood count which showed a hemoglobin of 8.0 mg/dl, platelets of 23 x 1000/mm2 and a white blood cell count of 78 x 1000/mm2 with almost all cells being small round blue cells, which were later confirmed to be blasts.
The diagnosis of priapism secondary to new onset acute leukemia was made.
The patient’s clinical course included being admitted to the intensive care unit where he received hydration, leukopheresis, and pain control.
Aspiration of the corpus cavernosum with saline irrigation had minor relief of symptoms. Over the next 3 hours with leukophereis the patient had a decrease in the priapism and over the next 2 hours had resolution but some continued edema.
He was transferred to the floor where he completed his initial evaluation for acute lymphocytic leukemia and began his induction chemotherapy. He stated that he had some erections since the priapism.

Priapism is as unremitting, painful erection that is a true urological emergency.The corpora cavernosa engorgement causes compression of the venous outflow tracts, resulting in blood trapping within the corpora cavernosa. The corpora spongiosum and glans are not engorged.
Priapism can occur in any age group, with peaks at age 5-10 years and 20-50 years.

Low flow (ischemic) priapism is the most common type and is caused by an abnormal detumescence mechanism (the normal mechanism that release the venous blood ending an erection). This can be caused by excessive neurotransmitter release, blockage of the draining venules (as in sickle cell disease or leukemia), and changes in the smooth muscle of the corpora cavernosa.

Prolonged low flow priapism causes an ischemia state leading to fibrosis of the corporeal smooth muscle and cavernosal artery thrombosis. Low flow priapism lasting more than 24 hours often leads to permanent impotence.
If a malignancy is suspect then a pelvic computed tomographic scan may be indicated. Surgical treatment by shunting may be necessary if medical therapy similar to that which this patient received fails.

High-flow priapism is caused most often becuase of blunt or penetrating trauma causing a fistula between the cavernosal artery and the corpus cavernosum with unchecked flow. Doppler ultrasound or pelvic angiography may be helpful for determining fistula location.

Learning Point

Causes of priapism include:

  • Sickle cell anemia – most common cause
  • Amyloidosis
  • Asplenia
  • Black widow spider venom
  • Carbon monoxide poisoning
  • Dialysis
  • Fabry disease
  • Fat emboli
  • Leukemia and other cancers
  • Medications – alcohol, cocaine, antihypertensive, psychotropics, anticoagulants, male and female hormones, metoclopramide, omeprazole, medications for erectile dysfunction
  • Malaria
  • Trauma – blunt and penetrating
  • Thalassemia
  • Spinal cord injury
  • Vasculitis

Questions for Further Discussion
1. What are other urological emergencies?
2. What are presentations of acute leukemia?
3. What are presentations of acute sickle cell anemia?

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Information prescriptions for patients can be found at MEDLINEplus for this topic: Penis Disorders

To view current news articles on this topic check Google News.

Rudolph CD, et.al. Rudolph’s Pediatrics. 21st edit. McGraw-Hill, New York, NY. 2003:1740.

Parraga-Marquez M. Wahlheim, Stantucci RA. Priapism. eMedicine. (rev. 11/14/2004, cited 6/9/06) Available from the Internet at: http://www.emedicine.com/med/topic1908.htm

ACGME Competencies Highlighted by Case

  • Patient Care
    1. When interacting with patients and their families, the health care professional communicates effecively and demonstrates caring and respectful behaviors.
    2. Essential and accurate information about the patients is gathered.
    3. Informed decisions about diagnostic and therapeutic interventions based on patient information and preferences, up-to-date scientific evidence, and clinical judgment is made.
    4. Patient management plans are developed and carried out.
    5. Patients and their families are counseled and educated.
    7. All medical and invasive procedures considered essential for the area of practice are competency performed.
    8. Health care services aimed at preventing health problems or maintaining health are provided.
    9. Patient-focused care is provided by working with health care professionals, including those from other disciplines.

  • Medical Knowledge
    10. An investigatory and analytic thinking approach to the clinical situation is demonstrated.
    11. Basic and clinically supportive sciences appropriate to their discipline are known and applied.

  • Practice Based Learning and Improvement
    13. Information about other populations of patients, especially the larger population from which this patient is drawn, is obtained and used.
    14. Knowledge of study designs and statistical methods to appraisal clinical studies and other information on diagnostic and therapeutic effectiveness is applied.

    Donna M. D’Alessandro, MD
    Associate Professor of Pediatrics, Children’s Hospital of Iowa

    July 17, 2006