Stuttering Priapism

Stuttering priapism, also called recurrent or intermittent ischaemic priapism, is a pattern of repeated, painful, prolonged erections that resolve on their own, usually within 3 to 4 hours, with periods of normal detumescence between.

Episodes are often nocturnal. Each episode can progress to a major ischaemic priapism, which is an emergency.

It occurs in up to about 40% of adult men with sickle cell disease and is the commonest pattern in this group. It is also seen in thalassaemia, leukaemia, drug exposure and neurological disease.

Pathophysiology. In sickle cell disease, low nitric oxide availability, haemolysis and dysregulated cyclic guanosine monophosphate signalling, with down regulated phosphodiesterase type 5 activity, cause failed detumescence.

Sickling and venous outflow obstruction during nocturnal erections lead to stasis, hypoxia and acidosis.

Other causes: drugs (phosphodiesterase type 5 inhibitors, intracavernosal injection therapy, trazodone, antipsychotics, anticoagulants, cocaine, cannabis, testosterone), spinal cord disease, and idiopathic.

Repeated episodes cause cavernosal fibrosis and erectile dysfunction.

Rigid, painful erections without sexual stimulation, often at night, lasting from 30 minutes to several hours, resolving spontaneously, and recurring over days or weeks. The glans is soft. The pain is from ischaemia.

An episode lasting over 4 hours is a major ischaemic priapism and needs emergency treatment. Sickle cell crisis, fever, or blood disease features are often present.

• History: frequency, duration and timing of episodes, previous major episodes, drug use, and sickle cell or blood disease.
• Full blood count, reticulocytes, lactate dehydrogenase, haemoglobin electrophoresis or sickle solubility testing where sickle cell status is unknown, and clotting screen.
• During a major episode: cavernosal blood gas. Ischaemic priapism shows dark blood with pO2 under 30 mmHg, pCO2 over 60 mmHg and pH under 7.25. Penile duplex ultrasound shows absent cavernosal arterial flow.
• Between episodes: duplex ultrasound for fibrosis, and erectile function assessment.
• Urine toxicology when drug use is suspected.

Differential diagnosis.

• Major ischaemic priapism
• Non-ischaemic priapism after perineal trauma
• Normal nocturnal erections with pain from Peyronie disease
• Penile fracture or haematoma
• Sleep related painful erections
• Penile thrombosis

Acute episode:

• Self-management at onset: empty the bladder, walk or do squats, warm shower, oral analgesia. Oral pseudoephedrine 60 mg is used by some patients at onset, avoided in hypertension and ischaemic heart disease, with limited evidence.
• If over 4 hours (major episode): hydrate, give oxygen and analgesia (morphine 2 to 5 mg intravenously, titrated), and proceed to penile treatment without waiting for transfusion.
  • Aspiration of the corpora with a 19 to 21 gauge butterfly needle at the 3 or 9 o'clock position, with saline irrigation.
  • If it persists, intracavernosal phenylephrine 100 to 500 micrograms (diluted to 100 to 200 micrograms/mL) every 5 to 10 minutes for up to 1 hour, with blood pressure and pulse monitoring. Avoid in uncontrolled hypertension, ischaemic heart disease and monoamine oxidase inhibitor use.
  • Failure after 1 to 2 hours: distal shunt (Winter or T-shunt), then proximal shunt if needed. Early penile prosthesis may be offered for refractory ischaemic priapism over 36 hours with corporal fibrosis.
• Sickle cell disease: intravenous fluid, oxygen and pain control. Exchange transfusion for priapism alone is not advised, because of the risk of neurological complications.

Prevention of recurrence:

• Hydroxyurea in sickle cell disease: 15 mg/kg orally once daily, increased every 8 to 12 weeks to a maximum of 35 mg/kg daily, with full blood count monitoring (hold if neutrophils under 1.0 x 10^9/L or platelets under 80 x 10^9/L).
• Phosphodiesterase type 5 inhibitor in the flaccid state, given when the penis is not erect: tadalafil 5 mg orally once daily, or sildenafil 25 mg orally at night. Evidence is from small studies, and treatment starts under specialist supervision.
• Hormonal therapy when episodes persist: GnRH agonist (leuprorelin depot 3.75 mg intramuscularly every month, with a short anti-androgen cover at the start), or bicalutamide 50 mg orally once daily, or finasteride 5 mg orally once daily. Adverse effects include loss of libido, erectile dysfunction, hot flushes and loss of bone density. Use with caution in younger men and avoid when fertility is wanted.
• Self-injection of phenylephrine (a prepared dose of 100 to 200 micrograms) at the onset of an episode, after supervised teaching.

Special groups. Boys with sickle cell disease and priapism need paediatric haematology and urology review. Men wanting fertility avoid hormonal therapy.

Monitoring. Review every 3 months in the first year, with an episode diary. Erectile function and duplex ultrasound if episodes have been prolonged. Hydroxyurea blood counts monthly during titration, then every 3 months.

Referral and escalation. Refer to urology and haematology. Urgent referral for any episode over 4 hours.