Erectile dysfunction after sickle cell disease-associated recurrent ischemic priapism: profile and risk factors

Contemporary management of ischemic priapism: A 12-year population-based analysis from a large US database

BACKGROUND

Priapism is a urological condition characterized by a persistent erection. The management varies based on its subclassifications. Despite established clinical guidelines for ischemic priapism, there is a lack of large-scale research focused on patient characteristics and management strategies.

OBJECTIVES

To analyze the contemporary management of ischemic priapism in the US, exploring patient demographics and clinical characteristics, as well as predictors of erectile dysfunction (ED) and penile prosthesis implantation (PPI).

MATERIALS AND METHODS

We performed a retrospective analysis of the PearlDiver Mariner database, reviewing records from 2010-2021. Adult males diagnosed with ischemic priapism were included. Data analysis covered demographic, clinical variables, and management strategies. Predictors of de novo ED and PPI were evaluated using multivariable logistic regression analysis.

RESULTS

Of 36,120 patients, most (93%) received only medical management, and a minority underwent surgical interventions (penile shunt surgery [PSS], PPI or both). Medical management was typically effective, as 67.08% of the patients in this group experienced only one episode of priapism. However, de novo ED occurred in 16.57% of these patients. The majority of patients undergoing PPI had an inflatable prosthesis (81%). Older age (odds ratio, OR 1.02), the presence of metabolic diseases (OR 1.39), neurogenic disorders (OR 1.72), solid pelvic malignancies (OR 1.09), and multiple episodes of priapism were identified as significant predictors of de novo ED (all p < 0.05). Similarly, age (OR 1.03), the presence of metabolic diseases (OR 1.23), solid pelvic malignancies (OR 1.99), and multiple episodes of priapism were associated with higher likelihood of PPI (all p < 0.05).

CONCLUSION

Most cases of ischemic priapism are managed with the medical therapy. Less than 3% of patients with ischemic priapism receive PPI, and when this occurs an inflatable prosthesis is favored. Age, specific comorbidities, and multiple episodes of priapism appear to be significant predictors of ED and PPI.

Clinical outcomes of the Burnett "snake" maneuver shunt modification for ischemic priapism

BACKGROUND

Major ischemic priapism (IP) is defined as a persistent penile erection for >4 hours. IP may cause serious complications, especially if prompt resolution is not achieved. Therefore, selecting the most effective and usable shunt technique is crucial in IP cases that are refractory to medical therapy.

AIM

To compare the effectiveness and complication risks of distal corporoglanular shunt procedures with and without the Burnett "snake" maneuver.

METHODS

We conducted a retrospective study of patients who presented with IP and underwent surgical treatment at our institution between 2005 and 2021. The patients were categorized into 2 groups: group 1 (n = 26) underwent distal shunt + Burnett snake maneuver, and group 2 (n = 56) underwent distal shunt-only. Clinical history, parameters of IP, details of medical and surgical treatments, and follow-up information were evaluated.

OUTCOMES

Outcomes included differences in IP resolution and recurrence, functional erections, and complications between corporoglanular shunt procedures with and without the Burnett snake maneuver.

RESULTS

In group 1, 24 of 26 patients (92.3%) experienced priapism resolution with a single surgical intervention, while this outcome was observed in 30 of 56 patients (53.6%) in group 2 (P < .001). Notably, priapism recurrence was significantly lower in group 1, occurring in 1 of 24 patients (4.2%), as opposed to 8 of 30 patients (26.6%) in group 2 (P < .001). Of the patients with documented sexual function status at follow-up, functional erections (capable of penetration with or without phosphodiesterase 5 inhibitors) were noted in 6 of 14 patients (42.8%) in group 1 and 13 of 26 patients (50%) in group 2 (P = .66).

CLINICAL IMPLICATIONS

This study provides valuable insights regarding technical aspects of distal shunt procedures with and without the Burnett snake maneuver for treating major IP episodes. These results can help surgeons with clinical decision making for patients who present with IP.

STRENGTH AND LIMITATIONS

Limitations include the single-site retrospective design with potential selection bias, inaccuracies in medical record data, challenges in controlling confounding variables, and the lack of validated questionnaire scores for erectile function evaluation.

CONCLUSION

Our study demonstrates that modifying distal shunt procedures using the Burnett snake maneuver significantly improves priapism resolution and effectively prevents further priapism episodes without introducing additional complications or erectile function loss, thereby distinguishing it from distal shunt-only procedures.

Nitric Oxide Resistance in Priapism Associated with Sickle Cell Disease: Mechanisms, Therapeutic Challenges, and Future Directions

Patients with sickle cell disease (SCD) display priapism, a prolonged penile erection in the absence of sexual arousal. The current pharmacological treatments for SCD-associated priapism are limited and focused on acute interventions rather than prevention. Thus, there is an urgent need for new drug targets and preventive pharmacological therapies for this condition. This review focuses on the molecular mechanisms linked to the dysfunction of the NO-cyclic guanosine monophosphate (cGMP)-phosphodiesterase type 5 (PDE5) pathway implicated in SCD-associated priapism. In murine models of SCD, reduced nitric oxide (NO)-cGMP bioavailability in the corpus cavernosum is associated with elevated plasma hemoglobin levels, increased reactive oxygen species levels that inactive NO, and testosterone deficiency that leads to endothelial nitric oxide synthase downregulation. We discuss the consequences of the reduced cGMP-dependent PDE5 activity in response to these molecular changes, highlighting it as the primary pathophysiological mechanism leading to excessive corpus cavernosum relaxation, culminating in priapism. We also further discuss the impact of intravascular hemolysis on therapeutic approaches, present current pharmacological strategies targeting the NO-cGMP-PDE5 pathway in the penis, and identify potential pharmacological targets for future priapism therapies. In men with SCD and priapism, PDE5 inhibitor therapy and testosterone replacement have shown promising results. Recent preclinical research reported the beneficial effect of treatment with haptoglobin and NO donors. SIGNIFICANCE STATEMENT: This review discusses the molecular changes that reduce NO-cGMP bioavailability in the penis in SCD and highlights pharmacological targets and therapeutic strategies for the treatment of priapism, including PDE5 inhibitors, hormonal modulators, NO donors, hydroxyurea, soluble guanylate cyclase stimulators, haptoglobin, hemopexin, and antioxidants.

Hydroxyurea does not reverse functional alterations of the nitric oxide-cGMP pathway associated with priapism phenotype in corpus cavernosum from sickle cell mouse

Sickle cell disease (SCD) is a genetic disorder that has been associated with priapism. The role of hydroxyurea, a common SCD therapy, in influencing the nitric oxide (NO)-cGMP pathway and its effect on priapism is unclear. To investigate the effect of hydroxyurea treatment on smooth muscle relaxation of corpus cavernosum induced by stimulation of the NO-cGMP pathway in SCD transgenic mice and endothelial NO synthase gene-deficient (eNOS-/-) mice, which are used as model of priapism associated with the low bioavailability of endothelial NO. Four-month-old wild-type (WT, C57BL/6), SCD transgenic, and eNOS-/- male mice were treated with hydroxyurea (100 mg/Kg/day) or its vehicle (saline) daily for three weeks via intraperitoneal injections. Concentration-response curves for acetylcholine (ACh), sodium nitroprusside (SNP), and electrical field stimulation (EFS) were generated using strips of mice corpus cavernosum. The SCD mice demonstrated an amplified CC relaxation response triggered by ACh, EFS, and SNP. The corpus cavernosum relaxation responses to SNP and EFS were found to be heightened in the eNOS-/- group. However, the hydroxyurea treatment did not alter these escalated relaxation responses to ACh, EFS, and SNP in the corpus cavernosum of the SCD group, nor the relaxation responses to EFS and SNP in the eNOS-/- group. In conclusion, hydroxyurea is not effective in treating priapism associated with SCD. It is likely that excess plasma hemoglobin and reactive oxygen species, which are reported in SCD, are reacting with NO before it binds to GCs in the smooth muscle of the corpus cavernosum, thus preventing the restoration of baseline NO/cGMP levels. Furthermore, the downregulation of eNOS in the penis may impair the pharmacological action of hydroxyurea at the endothelial level in SCD mice. This study emphasize the urgency for exploring alternative therapeutic avenues for priapism in SCD that are not hindered by high plasma hemoglobin and ROS levels.

Evaluation of knowledge of priapism in sickle cell patients in Senegal

PURPOSE

Erectile dysfunction is a dreadful complication of priapism especially with delay in diagnosis and management. The lack of awareness of priapism as a vaso-occlusive complication of sickle cell disease (SCD) is more concerning. The objective of this study was to evaluate the burden of priapism in adult Senegalese males adults with sickle cell disease.

METHODS

A cross-sectional study was carried out amongst consecutive consenting males aged 18 years and older with SCD presenting to the in Haematology Department of the National Blood Transfusion Centre (Dakar, Senegal). All participants completed a questionnaire detailing knowledge on the definition of priapism, its association with SCD, consequences of untreated priapism and treatment options.

RESULTS

A total of 219 participants completed the questionnaire. The mean age of the respondents was 27.1 years with a range of (18-54). Of the respondents, 78.5% (n = 172) did not have any knowledge of the term "priapism". After the term was explained, 38.4% (n = 84) thought that there may be a risk of developing priapism given the diagnosis of sickle cell disease. Among the participants, 41.5% (n = 91) reported having a history of priapism. Among all patients who experienced priapism, 36.3% (n = 33) did not seek medical attention with episodes of priapism. It was found that 48.4% (n = 106) of the participants thought there may be a risk of irreversible complications associated with priapism and a corresponding proportion, 42% (n = 92) thought this risk was time dependent. 36.5% (n = 80) of patients believed priapism could lead to erectile dysfunction.

CONCLUSION

Priapism is a common complication of sickle cell disease in Senegalese adults which is not well known by sickle cell patients. The health authorities must undertake efforts to raise awareness of priapism as a complication amongst sickle cell patients.

A systematic review to assess the burden of ischemic priapism in patients with sickle cell disease

Introduction

Ischemic priapism is a serious condition characterized by a persistent and painful involuntary erection. Patients with sickle cell disease (SCD) are at an elevated risk of experiencing priapism, with approximately 40% experiencing priapism during their lifetime.

Objectives

This systematic literature review (SLR) sought to identify studies reporting the clinical, humanistic, and economic burden of SCD-related priapism.

Methods

MEDLINE, Embase, Cochrane CENTRAL/CDSR, and 14 congresses were searched. Results were screened against predefined criteria and studies assessing relevant aspects of burden for human patients with SCD-related priapism were included. Outcomes of interest included rates of erectile dysfunction (ED), other disease-related complications, health-related quality of life (HRQoL), and economic burden.

Results

Of 1,236 publications identified, 34 were included. Most studies were retrospective observational (21). Sample size varied widely (range, 15–10,788). Study publication dates ranged from November 1980 through April 2018. Twenty-one studies reported clinical burden, with findings falling into 4 categories-priapism duration, recurrence frequency, incidence/severity of ED, and other complications. Nineteen studies reported humanistic burden, finding limited use of validated HRQoL measures such as the International Index of Erectile Function and the Priapism Impact Profile. Other patient-reported humanistic outcomes included worse scores on sleep-related indices and low rates of satisfactory intercourse. Eight studies reported economic burden. Direct treatment costs ranged from $4,996 for patients without penile operations to $22,906 (2019 USD) for patients receiving transfusions and urologic procedures.

Conclusions

This SLR identified 34 studies providing evidence of the burden of priapism for patients with SCD, including painful complications and diminished physical, mental and sexual function.

Fertility preservation for pediatric patients with hemoglobinopathies: Multidisciplinary counseling needed to optimize outcomes

Hemoglobinopathies are autosomal recessive disorders that occur when genetic mutations negatively impact the function of hemoglobin. Common hemoglobinopathies that are clinically significant include sickle cell disease, alpha thalassemia, and beta thalassemia. Advancements in disease-modifying and curative treatments for the common hemoglobinopathies over the past thirty years have led to improvements in patient quality of life and longevity for those who are affected. However, the diseases, their treatments and cures pose infertility risks, making fertility preservation counseling and treatment an important part of the contemporary comprehensive patient care. Sickle cell disease negatively impacts both male and female infertility, primarily by testicular failure and decreased ovarian reserve, respectively. Fertility in both males and females with beta thalassemia major are negatively impacted by iron deposition due to chronic blood transfusions. Hematopoietic stem cell transplant (HSCT) is currently the only curative treatment for SCD and transfusion dependent beta thalassemia. Many of the conditioning regimens for HSCT contain chemotherapeutic agents with known gonadotoxicity and whole-body radiation. Although most clinical studies on toxicity and impact of HSCT on long-term health do not evaluate fertility, gonadal failure is common. Male fertility preservation modalities that exist prior to gonadotoxic treatment include sperm banking for pubertal males and testicular cryopreservation for pre-pubertal boys. For female patients, fertility preservation options include oocyte cryopreservation and ovarian tissue cryopreservation. Oocyte cryopreservation requires controlled ovarian hyperstimulation (COH) with ten to fourteen days of intensive monitoring and medication administration. This is feasible once the patient has undergone menarche. Follicular growth is monitored via transvaginal or transabdominal ultrasound, and hormone levels are monitored through frequent blood work. Oocytes are then harvested via a minimally invasive approach under anesthesia. Complications of COH are more common in patients with hemoglobinopathies. Ovarian hyperstimulation syndrome creates a greater risk to patients with underlying vascular, pulmonary, and renal injury, as they may be less able to tolerate fluids shifts. Thus, it is critical to monitor patients undergoing COH closely with close collaboration between the hematology team and the reproductive endocrinology team. Counseling patients and families about future fertility must take into consideration the patient's disease, treatment history, and planned treatment, acknowledging current knowledge gaps.

An overview of emergency pharmacotherapy for priapism

INTRODUCTION

Priapism is a compartment syndrome, defined as an unwanted penile erection lasting longer than four hours, unrelated to sexual stimulation, and persistent even after ejaculation/orgasm. Ischemic priapism is considered a urologic emergency requiring time-sensitive management. Studies have documented that untreated priapism is associated with progressive ischemic histological changes in the corpora cavernosa, such as widespread smooth muscle necrosis, blood vessel and nerve attrition, and trabecular fibrosis. Treatment options include conservative management, corporal irrigation, pharmacologic therapy, and surgery. We herein provide an overview of the emergency pharmacology for priapism.

AREAS COVERED

The American Urological Association (AUA) and the European Association of Urology (EAU) both recommend penile aspiration in conjunction with intracavernosal injection of sympathomimetics as the initial management of ischemic priapism. We have performed a retrospective review of the literature from 1914 to 2022 by using PubMed and a review of the treatment guidelines from the AUA and the EAU to discuss the various therapies for ischemic priapism in the emergent setting.

EXPERT OPINION

After a thorough overview of the literature regarding the treatment of ischemic priapism in the emergent setting, we conclude that intracavernosal phenylephrine is superior to other agents due to its demonstrated efficacy and limited systemic side effects.

Fertility after Curative Therapy for Sickle Cell Disease: A Comprehensive Review to Guide Care

Curative therapy for sickle cell disease (SCD) currently requires gonadotoxic conditioning that can impair future fertility. Fertility outcomes after curative therapy are likely affected by pre-transplant ovarian reserve or semen analysis parameters that may already be abnormal from SCD-related damage or hydroxyurea treatment. Outcomes are also likely affected by the conditioning regimen. Conditioning with myeloablative busulfan and cyclophosphamide causes serious gonadotoxicity particularly among post-pubertal females. Reduced-intensity and non-myeloablative conditioning may be acutely less gonadotoxic, but more short and long-term fertility outcome data after these approaches is needed. Fertility preservation including oocyte/embryo, ovarian tissue, sperm, and experimental testicular tissue cryopreservation should be offered to patients with SCD pursing curative therapy. Regardless of HSCT outcome, longitudinal post-HSCT fertility care is required.

Rare emergency in children: Priapism and stepwise treatment approach

BACKGROUND

Priapism is a rare condition in children and the treatment algorithm is controversial in this age group. Herein, we report eight cases with low-flow priapism and our stepwise treatment approach in light of literature.

METHODS

We present a simple stepwise treatment for low-flow priapism including five steps. Step 1: Cold compress and analgesia while evaluation the priapism and its etiology. Step 2: Corporal aspiration and adrenaline infusion in the ward. Step 3: Modified Winter shunt in the same place. Step 4: Ketamine application and caudal block in the operating room. Step 5: Sapheno-cavernous (Grayhack) shunt. Eight cases with low-flow priapism were reviewed retrospectively. Symptoms, duration of tumescence, the interventions, and step that provide detumescence were recorded.

RESULTS

The mean age of patients was 8.5 years (1-17 y). The median time of the priapism before admission was 15 h (4-165 h). The etiological factors were sickle cell disease, hemodialysis due to chronic renal failure, and factor V Leiden mutation in three patients. Detumescence was achieved in one patient at Step 2, in two patients at Steps 3, 4, and 5, respectively. Rigidity of cavernous body was observed in one patient in long-term follow-up.

CONCLUSION

Low-flow priapism is a urological emergency that may cause erectile dysfunction. Treatment options should be selected according to a protocol that prevents time loss and avoids more invasive treatment in unnecessary situations. Our algorithm with simple nature and its steps from less invasive to more invasive procedures may be an alternative for the treatment of low-flow priapism.

Psychometric Impact of Priapism on Lives of Adolescents and Adults With Sickle Cell Anemia: A Sequential Independent Mixed-Methods Design

Despite priapism being one of the most frequent complications of sickle cell anemia (SCA) in male individuals, little has been reported about the impact of priapism in this population. The authors used a sequential independent mixed-methods design, which used both international multicenter focus group discussions (n=35) and a quantitative patient-reported outcome measure (n=131) to determine the impact of priapism on men with SCA in Nigeria and the United States. The authors analyzed data from focus groups using an iterative inductive-deductive approach. Comparison of the Priapism Impact Profile data was done using the Kruskal-Wallis H test. Our result showed that priapism, across cultures, is associated with shame and embarrassment. These emotions interfere with timely clinical and family communication about priapism symptoms and complications. Participants were dissatisfied with the quality of care at emergency facilities. The quality of life and physical wellness of men with SCA-related priapism were significantly different for the 3 groups: (1) priapism condition getting better, (2) priapism condition getting worse, and (3) priapism condition remain the same (P=0.002 and P=0.019, respectively). Psychological, sexual, and physical wellbeing are all adversely affected by priapism. Evidence-based methods are necessary for adequate medical, educational, and psychological treatment for recurrent priapism.

Testosterone Deficiency in Sickle Cell Disease: Recognition and Remediation

Hypogonadism is common in men with sickle cell disease (SCD) with prevalence rates as high as 25%. Testicular failure (primary hypogonadism) is established as the principal cause for this hormonal abnormality, although secondary hypogonadism and compensated hypogonadism have also been observed. The underlying mechanism for primary hypogonadism was elucidated in a mouse model of SCD, and involves increased NADPH oxidase-derived oxidative stress in the testis, which reduces protein expression of a steroidogenic acute regulatory protein and cholesterol transport to the mitochondria in Leydig cells. In all men including those with SCD, hypogonadism affects physical growth and development, cognition and mental health, sexual function, as well as fertility. However, it is not understood whether declines in physical, psychological, and social domains of health in SCD patients are related to low testosterone, or are consequences of other abnormalities of SCD. Priapism is one of only a few complications of SCD that has been studied in the context of hypogonadism. In this pathologic condition of prolonged penile erection in the absence of sexual excitement or stimulation, hypogonadism exacerbates already impaired endothelial nitric oxide synthase/cGMP/phosphodiesterase-5 molecular signaling in the penis. While exogenous testosterone alleviates priapism, it disadvantageously decreases intratesticular testosterone production. In contrast to treatment with exogenous testosterone, a novel approach is to target the mechanisms of testosterone deficiency in the SCD testis to drive endogenous testosterone production, which potentially decreases further oxidative stress and damage in the testis, and preserves sperm quality. Stimulation of translocator protein within the transduceosome of the testis of SCD mice reverses both hypogonadism and priapism, without affecting intratesticular testosterone production and consequently fertility. Ongoing research is needed to define and develop therapies that restore endogenous testosterone production in a physiologic, mechanism-specific fashion without affecting fertility in SCD men.

External validation of the priapism impact profile in a Jamaican cohort of patients with sickle cell disease

BACKGROUND

Priapism impairs quality of life and has a predilection for males with sickle cell disease (SCD). The Priapism Impact Profile (PIP) is a novel 12-item instrument designed to measure general health-related impact of priapism. The aim of the study was to evaluate the validity and reliability of the PIP in a Jamaican cohort of SCD patients experiencing priapism.

METHODS

One hundred SCD patients with a history of priapism were recruited from a sickle cell clinic in Kingston, Jamaica and administered the PIP questionnaire. Patients rated each item of the PIP for clarity and importance. Statistical testing was employed to evaluate the psychometric performance of the PIP. Content validation was assessed based on patient descriptive rating of the items based on clarity, and importance and criterion-oriented validity were assessed by evaluating the PIP's ability to distinguish between patient subgroups. Test-retest repeatability was assessed in 20 of the 100 patients.

RESULTS

Patients were stratified into active (54) and remission (46) priapism groups based on their experience of priapism within the past year. Patients in the active priapism group were younger (p = 0.011), had a shorter duration of disease (p = 0.023), and had more frequent priapism episodes (p = 0.036) than the remission group. PIP questionnaire scores differed significantly with respect to priapism activity (p < 0.001) and prevalence of erectile dysfunction (p < 0.05) but not by priapism severity (p = 0.62). The PIP questionnaire had good content validity, with questions rated as having medium or high clarity and importance by an average of 82.8% and 69.2% of patients, respectively.

CONCLUSION

The PIP questionnaire was successfully validated in a Jamaican cohort of SCD patients and adequately discriminated patients with active priapism from those in remission. The instrument may be utilized in routine clinical management of patients with SCD-associated priapism. Further clinical investigations are warranted in other populations.

Socioeconomic Disparities and Risk Factors in Patients Presenting With Ischemic Priapism: A Multi-Institutional Study

OBJECTIVES

To evaluate contemporary clinical presentations of priapism, their association with socioeconomic characteristics, and the role of prescribing providers in priapism episodes in a large cohort of patients managed at 3 major academic health systems.

METHODS

We identified all consecutive patients presenting with ischemic priapism to the emergency departments of three major academic health systems (2014 -2019). Demographic characteristics, priapism etiologies, and clinical management were evaluated. Univariable and multivariable analyses were used to assess the contribution of socioeconomic characteristics and the role of prescribing providers in priapism episodes.

RESULTS

We identified 102 individuals with a total of 181 priapism encounters. Hispanic race, lower income quartile, sickle-cell disease, and illicit drug use were associated with increased risk of recurrent episodes. Of ICI users, 57% received their prescriptions from non-urological medical professionals (NUMPs); the proportion with recurrent episodes was higher for NUMPs compared to urologists (24% vs 0%, P = 0.06) with no demographic differences identified between patients treated by either group.

CONCLUSION

Socioeconomic disparities exist among patients presenting with recurrent episodes of priapism, potentially highlighting systemic issues with access to care and patient education. With most patients who developed ischemic priapism from ICI being prescribed these medications by NUMPs, further investigation is required to elucidate the prescribing and counseling patterns of these providers. Increased awareness of disparities and complications may improve patient safety.

Long-term outcome of sexual function in sickle cell disease men with ischemic priapism: A systematic review

Purpose:

The purpose of this study was to have an accurate estimate about the sexual function of sickle cell disease adult men with previous history of recurrent attacks of ischemic priapism in childhood. We assessed the studies for their precise documentation for the erectile function in this group of patients.

Materials and methods:

We performed a systematic review of the literature by querying PubMed, Medline, and Cochrane. We included original studies on adult patients with sickle cell disease and history of ischemic priapism.

Results:

We identified 15,057 publications, of which 10 met the study inclusion criteria. The incidence of erectile dysfunction was reported up to 69.20% in one study.

Conclusion:

More extended prospective studies are required as multicenter studies to find the exact incidence of erectile dysfunction in men with sickle cell disease and priapism.

Level of evidence:

Level of evidence is not applicable for this systematic review.

Medical treatment of recurrent ischaemic priapism: a review of current molecular therapeutics and a new clinical management paradigm

OBJECTIVES

To examine the current molecular therapeutics in the medical treatment of recurrent ischemic priapism (RIP). To propose a stepwise clinical management paradigm for the treatment of RIP.

METHODS

We performed a literature search using the PubMed database for the terms 'recurrent ischemic priapism' and 'stuttering priapism' up until December 2020. We assessed pre-clinical and clinical studies regarding medical management of RIP and molecular pathophysiology. Case series and randomized trials were evaluated by study quality and patient outcomes to determine a potential clinical management scheme.

RESULTS

Recent research has fostered an improved understanding of the underlying molecular pathophysiology of RIP that has paved the way forward for developing new therapeutic agents. Medications targeting neurovascular, hormonal and haematological mechanisms associated with RIP show great promise towards remedying this condition. A host of therapeutic agents operating across different mechanistic directions may be implemented according to a clinical management scheme to potentially optimize RIP outcomes.

CONCLUSION

RIP remains a medically neglected condition with current management focused on treating the acute condition rather than modulating the course of disease. Continued research into the molecular mechanisms of RIP and standardized clinical pathways can improve the quality of care for patients suffering from this condition.

Men with sickle cell disease experience greater sexual dysfunction when compared with men without sickle cell disease

Recurrent ischemic priapism is a common complication of sickle cell disease (SCD). We assessed the burden, characteristics, and types of priapism, including sexual dysfunction, in a cohort of men with and those without SCD, to test the hypothesis that sexual dysfunction is more prevalent in men with SCD. In Kano, Nigeria, we conducted a comparative cross-sectional survey that included 500 and 250 men 18 to 40 years of age, with and without SCD, respectively. The survey used the Priapism Questionnaire and the International Index of Erectile Function for sexual function assessment. All eligible participants approached for the study gave informed consent and were enrolled. Stuttering and major priapism were defined based on the average duration of priapism experiences that lasted ≤4 and >4 hours, respectively. The prevalence of priapism was significantly higher in men with SCD than in those without it (32.6% vs 2%; P < .001). Stuttering priapism accounted for 73.6% of the priapism episodes in men with SCD. Nearly 50% of the participants with SCD-related priapism had never sought medical attention for this complication. The majority of the men with SCD-related priapism used exercise as a coping mechanism. Priapism affected the self-image of the men with SCD, causing sadness, embarrassment, and fear. The percentage of the men with SCD who had erectile dysfunction was more than twofold higher than that of those without SCD who had erectile dysfunction (P = .01). The men with SCD had a higher prevalence of priapism and sexual dysfunction than the men without SCD.

Mechanisms underlying priapism in sickle cell disease: targeting and key innovations on the preclinical landscape

Introduction: Priapism is prolonged penile erection in the absence of sexual arousal or desire and is a devastating condition affecting millions of patients with sickle cell disease (SCD) globally. Available drug treatments for SCD-related priapism remain limited and have been primarily reactive rather than preventive. Hence, there is an unmet need for new drug targets and pharmacologic therapies.Areas covered: We examine the molecular mechanisms underlying SCD-associated priapism evaluated mostly in animal models. In mouse models of SCD, molecular defects of priapism operating at the cavernous tissue level include reduced tonic NO/cGMP signaling, elevated oxidative/nitrosative stress, vascular adhesion molecule derangements, excessive adenosine and opiorphin signaling, dysregulated vasoconstrictive RhoA/ROCK signaling, and testosterone deficiency. We discuss the consequences of downregulated cGMP-dependent phosphodiesterase type 5 (PDE5) activity in response to these molecular signaling derangements, as the main effector mechanism causing unrestrained cavernous tissue relaxation that results in priapism.Expert opinion: Basic science studies are crucial for understanding the underlying pathophysiology of SCD-associated priapism. Understanding the molecular mechanisms could unearth new therapeutic targets for this condition based on these mechanisms. Treatment options should aim to improve deranged erection physiology regulatory signaling to prevent priapism and potentially restore or preserve erectile function.

Resolution of Acute Priapism in Two Children With Sickle Cell Disease Who Received Nitrous Oxide

BACKGROUND

Nitrous oxide (N O) is an inhalational medication that has anxiolytic, amnestic, potent venodilatory and mild-to-moderate analgesic properties commonly used in the emergency department (ED) setting. N₂ O has a rapid onset of action (<5 minutes) and recovery (<5 minutes) and can be quickly titrated to effect without the need for IV access. It has few side effects, does not require renal or hepatic metabolism for excretion and has no reports of allergic reaction. Priapism is a serious complication of sickle cell disease (SCD) affecting approximately 35% of males, with an adverse impact on quality of life. Treatment options are limited and not evidence based, including hydration, alkalization, analgesia, oxygenation to prevent further sickling, and exchange transfusion. Patients who do not respond within 4 hours often require a painful invasive procedure that includes aspiration of blood from the corpus cavernosum and phenylephrine injections. Case reports have described a therapeutic benefit from oral pseudoephedrine, sildenafil, and intravenous (IV) arginine, however controlled clinical trials are lacking. Although a 50:50 nitrous oxide/oxygen mix is commonly used in France to enhance analgesia in patients with SCD and vasoocclusive pain events (VOE) not sufficiently responding to IV morphine, there are no reports of its use to treat priapism. We describe the effects of N₂ O for the treatment of acute priapism associated with SCD in a pediatric ED.

METHODS

This is a case series of two adolescent boys with Hb-SS who on 3 separate occasions presented to the ED with acute priapism that failed oral therapy (pseudoephedrine and opioids). N₂ O gas was utilized to help facilitate IV catheter placement.

RESULTS

In each presentation (at ages 8 and 10 years for patient 1; age 15 years for patient 2), the patient experienced complete resolution of the priapism within 4-15 min of receiving N₂ O (max 60%). The patients were discharged from the ED following each presentation and had no recurrence during the subsequent week.

CONCLUSIONS

Priapism is a challenging complication of SCD associated with long-term morbidity and a paucity of treatment options. Opioids are commonly used. Given the risks and inconsistent results of current recommended therapy, N₂ O may represent a potential opioid-sparing treatment option for priapism presenting to the ED that warrants further investigation. Although anecdotal, N₂ O inhalation is an intervention to consider during a time when a treating ED physician may have few alternatives.

Sleep-disordered breathing in patients with sickle cell disease

Sickle cell disease is one of the most common hereditary hemoglobinopathies worldwide, and its vaso-occlusive and hemolytic crises cause considerable patient morbidity. A growing body of evidence has shown that sleep-disordered breathing, and in particular, obstructive sleep apnea, occurs at high frequency in the sickle cell population, and that there is significant overlap in the underlying pathophysiology of these two conditions. Through a variety of mechanisms including nocturnal hypoxemia and increased oxidative stress, production of pro-inflammatory cytokines, and endothelial dysfunction, sickle cell anemia and sleep-disordered breathing potentiate each other's clinical effects and end-organ complications. Here, we will review the shared pathophysiologic mechanisms of these conditions and discuss their clinical sequelae. We will also examine the results of studies that have been carried out with clinical intervention of nocturnal hypoxemia in patients with sickle cell disease in the attempts to overcome the complications of the disease. Finally, we will propose the areas of investigation that merit further investigations in future in patients with sickle cell disease and sleep-disordered breathing.

Advances in the understanding of priapism

Priapism, a persistent penile erection lasting longer than 4 hours and unrelated to sexual activity, is one of the most common emergencies treated by urologists. Priapism can be categorized as ischemic, recurrent ischemic (stuttering), and non-ischemic. Advances in understanding the pathophysiology of various types of priapism have led to targeted management strategies. This review aims to provide an up-to-date picture of the pathophysiology and management of priapism. A search of Medline and PubMed for relevant publications using the term "priapism" was performed. In addition to the "classical" articles, emphasis was placed on publications from January 2013 to September 2016 to evaluate the most recent literature available. Though advances in both basic and clinical research continue and effective treatment options are available, methods for the prevention of priapism continue to be elusive.

Hydroxyurea therapy for sickle cell anemia

INTRODUCTION

Sickle cell anemia (SCA) is a severe, inherited hemoglobin disorder affecting 100,000 persons in the US and millions worldwide. Hydroxyurea, a once daily oral medication, has emerged as the primary disease-modifying therapy for SCA. The accumulated body of evidence over 30 years demonstrates that hydroxyurea is a safe and effective therapy for SCA, but hydroxyurea remains underutilized for a variety of reasons.

AREAS COVERED

In this review, we summarize the available evidence regarding the pharmacology, clinical, and laboratory benefits, and safety of hydroxyurea therapy for the treatment of SCA. The purpose of this review is to provide the reader a comprehensive understanding of hydroxyurea and to reinforce the fact that hydroxyurea is a safe and effective medication for the treatment of SCA.

EXPERT OPINION

In our opinion, hydroxyurea therapy should be considered standard-of-care for SCA, representing an essential component of patient management. Early initiation and broader use of hydroxyurea will alter the natural history of SCA, so affected children can live longer and healthier lives. In addition, hydroxyurea use should be extended to low-resource settings such as sub-Saharan Africa, where the burden of SCA and the need for hydroxyurea is arguably the greatest.

Nitrergic Mechanisms for Management of Recurrent Priapism

INTRODUCTION

Priapism is a condition involving prolonged penile erection unrelated to sexual interest or desire. The ischemic type, including its recurrent variant, is often associated with both physical and psychological complications. As such, management is of critical importance. Ideal therapies for recurrent priapism should address its underlying pathophysiology.

AIM

To review the available literature on priapism management approaches particularly related to nitrergic mechanisms.

METHODS

A literature review of the pathophysiology and management of priapism was performed using PubMed.

MAIN OUTCOME MEASURE

Publications pertaining to mechanisms of the molecular pathophysiology of priapism.

RESULTS

Nitrergic mechanisms are characterized as major players in the molecular pathophysiology of priapism. PDE5 inhibitors represent an available therapeutic option with demonstrated ability in attenuating these underlying nitrergic derangements. Several additional signaling pathways have been found to play a role in the molecular pathophysiology of priapism and have also been associated with these nitrergic mechanisms.

CONCLUSION

An increasing understanding of the molecular pathophysiology of priapism has led to the discovery of new potential targets. Several mechanism-based therapeutic approaches may become available in the future.

Priapism Impact Profile Questionnaire: Development and Initial Validation

OBJECTIVE

To create and evaluate a psychometric instrument that measures the impact of experiencing priapism from the patient perspective.

METHODS

The research protocol consisted of several phases as follows: (1) generating items, (2) composing a patient questionnaire, (3) administering the questionnaire to patients with both active and remitted (≥1 year without priapism episodes) histories of priapism, (4) performing internal consistency and criterion-oriented validity analyses in correlation with clinical histories and erectile function assessment tools, and (5) ascertaining psychometric properties of the instrument.

RESULTS

The final instrument comprised a 12-item Priapism Impact Profile (PIP) questionnaire, representing the following 3 domains adversely impacted by priapism: quality of life (QoL), sexual function (SF), and physical wellness (PW), with higher scores indicating inferior experience in respective domains. Internal consistency reliability coefficients for the total PIP score and the 3 domain scores were >0.75. Fifty-four patients (mean age, 31.7 ± 11.4 years) completed the questionnaire. Patients with active priapism (n = 42) had higher total, QoL, SF, and PW scores than those with priapism remission (n = 8; P <.05, P <.05, P = .09, and P <.01, respectively). Patients with a history of recurrent priapism episodes >2 hours in duration had higher total, QoL, SF, and PW scores than those with "very minor" priapism recurrences (≤2 hours in duration; P <.01, P <.01, P <.05, and P <.001, respectively). Patients with "mild-to-moderate" to "severe" erectile dysfunction had higher total, QoL, SF, and PW scores than those with no or "mild" erectile dysfunction (P <.05, P = .14, P <.01, and P = .25, respectively).

CONCLUSION

The PIP questionnaire is a novel psychometric instrument that offers a means to quantify the adverse health impact of the patient's experience with priapism.

How I treat priapism

Priapism is a disorder of persistent penile erection unrelated to sexual interest or desire. This pathologic condition, specifically the ischemic variant, is often associated with devastating complications, notably erectile dysfunction. Because priapism demonstrates high prevalence in patients with hematologic disorders, most commonly sickle cell disease (SCD), there is significant concern for its sequelae in this affected population. Thus, timely diagnosis and management are critical for the prevention or at least reduction of cavernosal tissue ischemia and potential damage consequent to each episode. Current guidelines and management strategies focus primarily on reactive treatments. However, an increasing understanding of the molecular pathophysiology of SCD-associated priapism has led to the identification of new potential therapeutic targets. Future agents are being developed and explored for use in the prevention of priapism.