Priapism in Sickle-Cell Disease: A Hematologist’s Perspective

Abstract

Introduction Priapism is a familiar problem to hematologists, well known for its association with sickle cell disease. It also occurs in a variety of other hematological illnesses, nearly all forms of congenital hemolytic anemia, including other hemoglobinopathies and red blood cell membranopathies and enzymopathies. Aim Provide urologists with a comprehensive review of priapism in sickle cell disease, with an emphasis on the perspective of a practicing hematologist. Methods Medline searches through July 2010 were conducted using the terms priapism, erectile dysfunction, and sickle cell. Main Outcome Measure Expert opinion was based on review of the medical literature related to this subject matter. Results In men with sickle cell disease, large epidemiological studies have linked the risk of priapism to clinical markers of the severity of intravascular hemolysis. Extracellular hemoglobin and arginase released during hemolysis has been implicated in reducing nitric oxide bioavailability, although the relevance of hemolysis to vascular dysfunction has been challenged by some scientists. Consistent with the role of impairment of the nitric oxide axis, mice genetically deficient in nitric oxide production have also been shown to develop priapic activity. Provocative new data indicates that hemolysis-linked dysregulation of adenosine signaling in the penis contributes to priapism in sickle cell mice. Serious questions have arisen regarding the efficacy of mainstays of textbook dogma for treatment of acute severe priapism, including intravenous fluids, alkalinization and exchange transfusion, and there is increasing acceptance for early aspiration and irrigation of the corpus cavernosum. Conclusions For sickle cell patients with recurrent priapism, there is very limited evidence for a medical prophylaxis role for hydroxyurea, etilefrine, pseudoephedrine, leuprolide, sildenafil, and other agents. Recent publications have highlighted nitric oxide and adenosine signal transduction pathways as worthy of additional research. Research and clinical management of sickle cell priapism is strengthened by multidisciplinary collaboration between hematologists and urologists.

Priapism in Homozygous Sickle Cell Disease: A 40 year Study of the Natural History

“…Late recovery of erectile function cautions against the early introduction of penile prostheses despite the fact that such surgery is technically easier in patients before fibrosis of the corpora cavernosa occurs. The relatively poor outcome of major attacks indicates that these should be avoided if at all possible, although with the exception of the small trial on diethylstilboestrol (4), there is currently little convincing evidence of the effectiveness of the many proposed prophylactic therapies (6). Stuttering episodes greater than once weekly may predict major attacks, similar to the observation of Emond et al (1) who noted that 28% of patients with stuttering events proceeded to a major attack.…”

Acute management of priapism in men

“…A proportion of patients develop a major episode of prolonged ischaemic priapism [ 19 ] . Stuttering priapism is more prevalent in patients with sickle cell disease due to hyperviscosity, increase adhesiveness of blood to vascular endothelium and disrupted vascular homeostasis [ 20,21 ] . About 28 -38% of patients with sickle cell disease experience priapism, with 89% of them reporting their fi rst priapic episode by the age of 20 years [ 22,23 ] .…”

Hydroxyurea treatment does not increase blood viscosity and improves red blood cell rheology in sickle cell anemia

“…10 Of importance, mean hemoglobin saturation increased with HU, hence improving the quality of life of patients.…”