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Recent advances in understanding and treating priapism (2022)
Hussain M. Alnajjar Asif Muneer
Abstract
Priapism is a rare condition that can lead to long-term erectile dysfunction if left untreated. It is one of the few urological emergencies that require prompt medical intervention. Priapism refers to a penile erection that lasts for more than 4 hours and is unrelated to sexual stimulation or orgasm. The aims of immediate intervention for ischaemic priapism are to resolve the painful erection and preserve the cavernosal smooth muscle function. The aim of this review is to evaluate the latest advances in the management of priapism. Despite the continuous challenge in providing an optimal treatment for this rare urological condition, our understanding and management of it have been advanced by decades of clinical and basic science research. Proximal shunts (Quackels or Grayhack) are no longer routinely performed. Distal shunt procedures are currently the most commonly used technique. A novel penoscrotal decompression technique has recently been described. Ischaemic priapism can be managed conservatively in most cases with the preservation of erectile function. In cases where ischaemic priapism has persisted for more than 36 hours, the majority will develop erectile dysfunction. Early penile prostheses with thorough patient counseling should be considered in such cases. In some cases of long-standing non-ischaemic priapism, patients can develop fibrosis within the distal corpora, and, therefore, early treatment with super-selective embolization is required to prevent this.
Introduction
Priapism is a rare condition and a urological emergency, with an estimated incidence of 1.5 cases per 100,000 men1. Ischaemic priapism is by far the commonest subtype and accounts for more than 95% of all priapism episodes2. Any delay in the presentation or failure to intervene in a timely fashion can lead to irreversible erectile dysfunction, penile shortening, loss of penile girth, and penile curvature. Despite over two decades of both clinical and basic science research, the pathophysiology of priapism is still not yet fully understood. However, various studies have suggested dysregulation of the normal neurovascular and veno-occlusive mechanisms which mediate physiological erection. Any disruption in this mechanism will lead to an unwanted prolonged erection3. There are three subtypes of priapism: ischaemic, non-ischaemic, and stuttering priapism, also known as recurrent ischaemic priapism.
Ischaemic priapism is the commonest subtype. The term ischaemic priapism is preferable to low-flow priapism, particularly when interpreting penile doppler imaging in the acute setting, as the term ‘ischaemic’ emphasizes a degree of clinical urgency in the management of this urological emergency4. Non-ischaemic priapism or high-flow priapism involves unregulated oxygenated arterial blood flow into the penis. As there is an absence of ischaemia, this is unlikely to result in smooth muscle necrosis. Idiopathic ischaemic priapism is common, although other risk factors include hematological dyscrasias, medications, illicit drugs, neurological disorders, and toxic infections, and rarely it can be secondary to malignant disease due to either pelvic malignancy or secondary infiltration into the corpora via hematogenous spread5,6, whereas penile and perineal trauma are common causes of non-ischaemic priapism.
In 2018, the British Association of Urological Surgeons published a consensus statement with clear recommendations on the assessment and management of acute priapism; the statement provides an algorithm to be used in non-specialist centers to undertake prompt treatment4
Clinical evaluation and investigations
Classically, a clinical history and examination are key to the diagnosis of priapism. Often the presentation is delayed and commonly past the critical 4-hour time frame, whereby cavernosal smooth muscle necrosis sets in. Patients presenting with priapism lasting longer than 4 hours will require immediate medical intervention.
Advances in radiological imaging in priapism
The diagnosis can be confirmed by a color penile Doppler ultrasonography, where the blood flow within the cavernosal arteries and corpus cavernosum can be evaluated. Colour penile Doppler imaging can further establish a reduced or absent blood flow of the cavernosal arteries with impaired perfusion of the corpus cavernosum in cases of prolonged ischaemic priapism. In atypical cases or where there is diagnostic uncertainty, a color penile Doppler ultrasound may confirm the diagnosis and detect an arterio-cavernous fistula9.
Management of priapism
Management of priapism focuses on four principles: controlling the acute pain, resolving the acute event, preserving erectile function, and preventing the risk of future recurrences. Conservative management is the mainstay in the treatment of early stages of priapism. This includes pain management, strenuous physical activity, ejaculation, and application of ice packs to the upper-inner thigh may induce detumescence by the sympathomimetic response; if conservative maneuvers fail, then a stepwise approach is used to resolve the acute event4. Those who are refractory to these interventions or who have prolonged priapism may benefit from the early placement of a penile prosthesis in the ischaemic cases or selective arterial embolization in non-ischaemic priapism.
A. Cavernosal decompression
B. Surgical shunts (corporo-glanular)
C. Implantation of penile prosthesis in the acute setting
Stuttering priapism
Stuttering priapism is the least common subtype and is usually a self-limiting condition. It generally lasts less than 3 to 4 hours per episode. However, it has the propensity to develop into full ischaemic priapism in 30% of cases. The condition shares its aetiologies with ischaemic priapism. The management of stuttering priapism aims primarily to prevent recurrence rather than the resolution of spontaneous attacks30
Non-ischaemic priapism
Non-ischaemic priapism results in persistent partial penile tumescence because of the high flow of arterial blood into the corpora as a result of trauma to the penis or perineum. Non-ischaemic priapism is much less common than the ischaemic subtype and does not require urgent surgical intervention. The flow of oxygenated blood within the corpora and the lack of severe penile pain permit non-ischaemic cases to be initially managed conservatively. Hence, at the outset, it is vital to have an accurate diagnosis that can be confirmed by Doppler ultrasonography. Following a period of conservative management, which necessitates regular outpatient clinical review, diagnostic angiography combined with super-selective embolization of the fistula can be performed with various agents or micro coils. The literature quotes erectile dysfunction rates as low as 5% when using temporary agents and 39% with permanent agents. However, a recent study demonstrated that erectile dysfunction rates were higher with temporary agents than with permanent agents (17–33% vs. 8–17%)35. Furthermore, the choice of the embolic agent seems to be crucial and should be tailored to each patient36.
In some cases of long-standing non-ischaemic priapism, patients can develop fibrosis within the distal corpora, and therefore, early treatment with super-selective embolization is required to prevent this. Patients with distal flaccidity and fibrosis within the distal corpus cavernosum should undergo a penile MRI scan as the best imaging modality in these scenarios37
Conclusions
Despite the continuous challenge in providing optimal treatment for this rare urological condition, our understanding and management of it have been advanced by decades of clinical and basic science research. Pharmacologic advances have considerably improved the management of stuttering priapism and the outlook of resolution for patients with ischaemic priapism presenting within the first few hours of the onset, whereas the management of non-ischaemic priapism is mainly expectant and only in persistent cases a super-selective embolization may be indicated. Distinguishing the ischaemic from the non-ischaemic state is conceivably the most important diagnostic step as it outlines the series of further interventions, including surgical shunts and early implantation of penile prosthesis in refractory cases.
Hussain M. Alnajjar Asif Muneer
Abstract
Priapism is a rare condition that can lead to long-term erectile dysfunction if left untreated. It is one of the few urological emergencies that require prompt medical intervention. Priapism refers to a penile erection that lasts for more than 4 hours and is unrelated to sexual stimulation or orgasm. The aims of immediate intervention for ischaemic priapism are to resolve the painful erection and preserve the cavernosal smooth muscle function. The aim of this review is to evaluate the latest advances in the management of priapism. Despite the continuous challenge in providing an optimal treatment for this rare urological condition, our understanding and management of it have been advanced by decades of clinical and basic science research. Proximal shunts (Quackels or Grayhack) are no longer routinely performed. Distal shunt procedures are currently the most commonly used technique. A novel penoscrotal decompression technique has recently been described. Ischaemic priapism can be managed conservatively in most cases with the preservation of erectile function. In cases where ischaemic priapism has persisted for more than 36 hours, the majority will develop erectile dysfunction. Early penile prostheses with thorough patient counseling should be considered in such cases. In some cases of long-standing non-ischaemic priapism, patients can develop fibrosis within the distal corpora, and, therefore, early treatment with super-selective embolization is required to prevent this.
Introduction
Priapism is a rare condition and a urological emergency, with an estimated incidence of 1.5 cases per 100,000 men1. Ischaemic priapism is by far the commonest subtype and accounts for more than 95% of all priapism episodes2. Any delay in the presentation or failure to intervene in a timely fashion can lead to irreversible erectile dysfunction, penile shortening, loss of penile girth, and penile curvature. Despite over two decades of both clinical and basic science research, the pathophysiology of priapism is still not yet fully understood. However, various studies have suggested dysregulation of the normal neurovascular and veno-occlusive mechanisms which mediate physiological erection. Any disruption in this mechanism will lead to an unwanted prolonged erection3. There are three subtypes of priapism: ischaemic, non-ischaemic, and stuttering priapism, also known as recurrent ischaemic priapism.
Ischaemic priapism is the commonest subtype. The term ischaemic priapism is preferable to low-flow priapism, particularly when interpreting penile doppler imaging in the acute setting, as the term ‘ischaemic’ emphasizes a degree of clinical urgency in the management of this urological emergency4. Non-ischaemic priapism or high-flow priapism involves unregulated oxygenated arterial blood flow into the penis. As there is an absence of ischaemia, this is unlikely to result in smooth muscle necrosis. Idiopathic ischaemic priapism is common, although other risk factors include hematological dyscrasias, medications, illicit drugs, neurological disorders, and toxic infections, and rarely it can be secondary to malignant disease due to either pelvic malignancy or secondary infiltration into the corpora via hematogenous spread5,6, whereas penile and perineal trauma are common causes of non-ischaemic priapism.
In 2018, the British Association of Urological Surgeons published a consensus statement with clear recommendations on the assessment and management of acute priapism; the statement provides an algorithm to be used in non-specialist centers to undertake prompt treatment4
Clinical evaluation and investigations
Classically, a clinical history and examination are key to the diagnosis of priapism. Often the presentation is delayed and commonly past the critical 4-hour time frame, whereby cavernosal smooth muscle necrosis sets in. Patients presenting with priapism lasting longer than 4 hours will require immediate medical intervention.
Advances in radiological imaging in priapism
The diagnosis can be confirmed by a color penile Doppler ultrasonography, where the blood flow within the cavernosal arteries and corpus cavernosum can be evaluated. Colour penile Doppler imaging can further establish a reduced or absent blood flow of the cavernosal arteries with impaired perfusion of the corpus cavernosum in cases of prolonged ischaemic priapism. In atypical cases or where there is diagnostic uncertainty, a color penile Doppler ultrasound may confirm the diagnosis and detect an arterio-cavernous fistula9.
Management of priapism
Management of priapism focuses on four principles: controlling the acute pain, resolving the acute event, preserving erectile function, and preventing the risk of future recurrences. Conservative management is the mainstay in the treatment of early stages of priapism. This includes pain management, strenuous physical activity, ejaculation, and application of ice packs to the upper-inner thigh may induce detumescence by the sympathomimetic response; if conservative maneuvers fail, then a stepwise approach is used to resolve the acute event4. Those who are refractory to these interventions or who have prolonged priapism may benefit from the early placement of a penile prosthesis in the ischaemic cases or selective arterial embolization in non-ischaemic priapism.
A. Cavernosal decompression
B. Surgical shunts (corporo-glanular)
C. Implantation of penile prosthesis in the acute setting
Stuttering priapism
Stuttering priapism is the least common subtype and is usually a self-limiting condition. It generally lasts less than 3 to 4 hours per episode. However, it has the propensity to develop into full ischaemic priapism in 30% of cases. The condition shares its aetiologies with ischaemic priapism. The management of stuttering priapism aims primarily to prevent recurrence rather than the resolution of spontaneous attacks30
Non-ischaemic priapism
Non-ischaemic priapism results in persistent partial penile tumescence because of the high flow of arterial blood into the corpora as a result of trauma to the penis or perineum. Non-ischaemic priapism is much less common than the ischaemic subtype and does not require urgent surgical intervention. The flow of oxygenated blood within the corpora and the lack of severe penile pain permit non-ischaemic cases to be initially managed conservatively. Hence, at the outset, it is vital to have an accurate diagnosis that can be confirmed by Doppler ultrasonography. Following a period of conservative management, which necessitates regular outpatient clinical review, diagnostic angiography combined with super-selective embolization of the fistula can be performed with various agents or micro coils. The literature quotes erectile dysfunction rates as low as 5% when using temporary agents and 39% with permanent agents. However, a recent study demonstrated that erectile dysfunction rates were higher with temporary agents than with permanent agents (17–33% vs. 8–17%)35. Furthermore, the choice of the embolic agent seems to be crucial and should be tailored to each patient36.
In some cases of long-standing non-ischaemic priapism, patients can develop fibrosis within the distal corpora, and therefore, early treatment with super-selective embolization is required to prevent this. Patients with distal flaccidity and fibrosis within the distal corpus cavernosum should undergo a penile MRI scan as the best imaging modality in these scenarios37
Conclusions
Despite the continuous challenge in providing optimal treatment for this rare urological condition, our understanding and management of it have been advanced by decades of clinical and basic science research. Pharmacologic advances have considerably improved the management of stuttering priapism and the outlook of resolution for patients with ischaemic priapism presenting within the first few hours of the onset, whereas the management of non-ischaemic priapism is mainly expectant and only in persistent cases a super-selective embolization may be indicated. Distinguishing the ischaemic from the non-ischaemic state is conceivably the most important diagnostic step as it outlines the series of further interventions, including surgical shunts and early implantation of penile prosthesis in refractory cases.
