Sickle Cell Priapism

Priapism in sickle cell disease is a prolonged painful erection from ischaemic venous outflow obstruction in the corpora.

• Affects 30 to 45% of male patients, onset from age 5; stuttering (recurrent, self limiting under 3 to 4 hours) and major (over 4 hours) forms.
• Mechanism: sickling, nitric oxide depletion and PDE5 dysregulation.
• Complications: erectile dysfunction in 25 to 50% after major episodes.

• Painful rigid erection, often nocturnal or on waking, unrelated to sexual stimulation, glans soft.
• Stuttering episodes lasting under 3 hours, recurrent.
• Triggers: dehydration, infection, alcohol, sexual activity, PDE5 inhibitors.

• Clinical; corporal blood gas (pH under 7.25, PO2 under 30 mmHg) confirms ischaemic type.
• Full blood count, haemoglobin level, reticulocytes; colour Doppler (absent cavernosal flow).
• Exclude non ischaemic priapism, trauma, drugs.

• Stuttering priapism: hydration, analgesia, warm baths, exercise, early ejaculation; if lasting over 2 hours seek care.
• Major episodes (over 4 hours): emergency. Hydration, analgesia, oxygen, dorsal nerve block, aspiration of corporal blood with saline irrigation, intracavernosal phenylephrine 100 to 500 micrograms every 3 to 5 minutes (maximum 1 mg/h) with monitoring; shunt surgery if refractory after 1 hour. Avoid exchange transfusion as sole therapy (ASPEN syndrome risk).
• Prevention: hydroxyurea 15 to 35 mg/kg daily, pseudoephedrine 30 to 60 mg at night, oral phenylephrine, sildenafil 25 mg or tadalafil 5 mg daily (controlled, specialist), GnRH agonists or antiandrogens (bicalutamide 50 mg daily, finasteride 5 mg daily), chronic transfusion.
• Educate patients and parents; self injection of phenylephrine for selected patients.
• Penile prosthesis for permanent erectile dysfunction.