Priapism is a prolonged penile erection unrelated to sexual stimuli, primarily resulting from lacunar venous outflow obstruction or, less commonly, from arteriolacunar fistula formation. It represents an infrequent clinical condition in the pediatric population, the underlying causes of which may be difficult to identify. A case of childhood arterial priapism that occurred after cycling injury is reported, followed by a literature review to ensure appropriate management.
A 12-year-old white boy presented to our outpatient clinic with a 6-month history of painless penile erection. The erection was partial, although persistent.
The patient’s past medical history showed no features of congenital hematologic disease, drug intake, or prior surgery. A detailed anamnesis disclosed a low-energy traumatic cycling injury that occurred 2 days prior to the initiation of the persistent penile erection. The patient described having injured his genitalia with low energy against the bicycle wheel at an approximate velocity of 20 to 30 km/h. The trauma resulted in minimal pain, of the type that often occurs among cyclists. He continued cycling for the next 30 minutes, and did not use any medications or ice packs. The patient reported a mild dull pain since the day of injury; however, no signs of significant perineal or penile hematoma were evident.
The prolonged delay between the traumatic incident and the medical consult was due to the patient feeling shy and embarrassed, in particular with regard to disclosure of the problem to his parents. Lack of understanding regarding the gravity of the condition and its requirement of time-sensitive management was also an issue. On clinical evaluation, the patient had a rigid, nontender corpora cavernosa, with a soft glans and corpus spongiosum.
Routine laboratory test results (full blood count; urea, creatinine, and electrolyte levels; and sickle cell disease screening) were within normal limits, excluding the onset of any acquired hematologic disorders. Diagnostic intracorporeal blood gas analysis revealed bright red blood with a high oxygen saturation (PO2 = 87 mm Hg; PCO2 = 41 mm Hg; Ph = 7.36).
On penile Doppler ultrasonography, high arterial and venous flow in the corpora were shown, although pathologic fistula was not detected. The patient underwent pelvic arteriography, which clearly depicted a post-traumatic arteriolacunar fistula coming from the left bulbourethral artery (Figures 1 and 2).
The fistulous communication was selectively embolized with an absorbable hemostatic gelatin sponge. The immediate result was complete detumescence with return to a completely flaccid penis. A follow-up pelvic arteriogram was performed 2 weeks after embolization, and showed the absence of any fistula and patency of the left dorsal artery. At his 1-year follow-up visit, the boy reported normal spontaneous and reflexogenic erections with no evidence of priapism recurrence.
Priapism is a prolonged penile erection unrelated to sexual arousal. There are three different pathophysiologic types. The most common ischemic (or low-flow) subtype is characterized by a painful erection of the corpora cavernosa due to venous occlusion and vascular stasis, primarily associated with hematologic disorders (eg, sickle cell disease, hematopoietic malignancies, hypercoagulable states) or adverse drug reactions.1 Sickle cell anemia accounts for up to 65% of all priapism episodes occurring in children,2 whereas 29% to 42% of patients with sickle cell anemia develop priapism.3 In these cases, prompt intervention is required to avoid development of serious complications (eg, irreversible sexual dysfunction and disfigurement with subsequent emotional sequelae).
Stuttering priapism is relatively rare and mostly associated with various hematological disorders, including sickle cell disease.
The nonischemic (or high-flow) subtype is the result of arteriolacunar fistula formation with unregulated arterial filling of the corpora cavernosa, primarily occurring 24 to 48 hours after severe perineal blunt trauma and initiated by sexual stimuli.4 Because tissue oxygenation is usually preserved, the prognosis is typically favorable, even in the case of delayed treatment.5 However, cavernosal smooth-muscle damage and fibrosis are possible.6,7
The diagnostic work-up of priapism is based on a detailed history and physical examination, followed by intracorporeal blood gas analysis and color Doppler ultrasonography. For arterial priapism, the definitive diagnosis is by standard or magnetic resonance imaging pelvic angiography,8,9 which can detect arteriolacunar fistula.
Although it has established cardiovascular beneficial effects, bicycle riding is also a well-known cause of urologic disorders in adulthood (including nerve entrapment syndromes, erectile dysfunction, urethritis, prostatitis, hematuria, and spermatic cord torsion),10-12 among which high-flow priapism is included.10-14 Priapism is a rare but possible clinical condition in children; clinical work-up can be extremely arduous when the most frequent causes are excluded in this age group. A case report and literature review of cycling-induced priapism is reported here (Table 1) to draw attention to this rare cause for pediatric consultation.
Clinical onset of cycling-induced priapism depends on the entity of the vascular lesion: severe arterial damage usually leads to immediate penile tumescence, whereas small injuries cause priapism only when penile blood flow is increased during spontaneous erection, removing the clot that was previously masking the arteriolacunar fistula.11
Both conservative15 (mechanical or pharmacologic) and invasive16-24 (interventional radiologic and surgical) therapeutic options are described in children, even in cases reporting spontaneous resolution.8,16 However, the current accepted standard is angiographic superselective embolization (with absorbable autologous clot or gelatin sponge), which was safely demonstrated in our pediatric case. Nonabsorbable (microcoils or N-butyl-cianoacrilato) materials25 should be used in case of failure of embolization with absorbable materials, due to the increased risk of erectile dysfunction.26
Because priapism is an uncommon problem in childhood, its management could be a clinical challenge for pediatric urologists. Although most pediatric cases are due to venous outflow obstruction associated with hematologic disorders, the post-traumatic arterial subtype is also possible. Recognition of the latter form, particularly in the pediatric population, may be challenging due to its delayed onset, its intermittence, and the absence of pain. Furthermore, the embarrassment a teenager may feel may prevent him from disclosing the problem to his parents, further delaying diagnosis and management. This delay can often be as long as days or weeks27,28 and is usually related to low-intensity trauma; it is not necessarily associated with other symptoms (eg, hematoma, hematuria)27,29 and therefore can be inadequately evaluated by children and parents. For all these reasons, a delayed diagnosis is possible, which can lead to irreversible penile changes with future sexual problems.
Most pediatric patients treated with both the conservative approach and embolization report complete detumescence and preserved functional results after a short-term follow-up period.15-17,27,29 When the onset is immediate, it is possible to delay the invasive approach and wait for possible spontaneous resolution of the disease. Alternatively, when conservative management fails or there is delay in presentation to the pediatric/urologic department beyond 6 weeks,27 as in our case, an arteriography with embolization becomes mandatory. An imaging control study 1 to 2 weeks after the embolization is advisable. Doppler sonography should be the first choice, but a repeat angiogram may be indicated in specific cases. The absence of fistula detected at the first sonography, and the huge delay before treatment, coupled with an increased risk of recurrence, led us to choose the execution of control arteriography to ensure the complete resolution of the fistula.
Every day, millions of children practice cycling. Although it has cardiovascular benefits, the perineal position on a bicycle exposes boys and men to the risk of recurrent blunt trauma with resultant urogenital injuries. To ensure prompt diagnosis and management, pediatricians should be aware that, though uncommon, childhood high-flow priapism could be related to cycling-related trauma. Early recognition and appropriate treatment of this distinct entity is important as it is associated with excellent functional prognosis.