Priapism
A painful erection lasting over 4 hours is a compartment syndrome of the penis. Call urology now.
A 19-year-old with sickle cell disease has had a painful erection for 6 hours.
A 45-year-old man had an injection for erectile dysfunction 5 hours ago and the erection hasn't settled. It is rigid and painful.
A 30-year-old man has a painless, partly firm erection for 3 days after a straddle injury.
Which of these are emergencies, and what do you do in the first hour?
- Painful, rigid erection for more than 4 hoursIschaemic priapism: urology emergency.
- HistoryDuration, pain, trauma, sickle cell, drugs (injections, PDE5 inhibitors, antipsychotics, trazodone, cocaine).
- Cavernosal blood gasDark blood, low pH and O₂, high CO₂ means ischaemic.
- AnalgesiaPenile block or IV analgesia.
- Aspiration and irrigationBy urology or trained doctor.
- Then intracavernosal phenylephrineWith BP and ECG monitoring.
- Non-ischaemicPainless, partly rigid, often after trauma: not an emergency, urology follow-up.
- Any painful erection over 4 hours
- Sickle cell priapism
- Failed aspiration
- High BP or arrhythmia with phenylephrine
- Recurrent episodes (stuttering priapism)
- Ischaemic priapism treated as non-urgent
- Sickle cell crisis elsewhere
- Drug cause
- Malignancy infiltrating the penis (rare)
- Non-ischaemic priapism treated with aspiration unnecessarily
| Emergency threshold | Erection over 4 hours |
| Ischaemic gas | pH below 7.25, PO₂ below 30 mmHg, PCO₂ above 60 mmHg, dark blood |
| Non-ischaemic gas | Bright red, similar to arterial blood |
| Phenylephrine (intracavernosal) | 100–200 micrograms every 3–5 minutes, max 1 mg in 1 hour, specialist use |
| Damage risk | Rises after 4–6 hours, high after 24–48 hours |
| Sickle cell | Fluids, oxygen, analgesia, haematology |
Check every dose against a current drug reference and your hospital protocol.
On this page
Types
| Type | Cause | Features | Urgency |
|---|---|---|---|
| Ischaemic (low-flow) | Blood trapped, no outflow | Painful, fully rigid, dark blood | Emergency |
| Non-ischaemic (high-flow) | Arterial fistula after trauma | Painless, partly rigid, bright red blood | Not an emergency |
| Stuttering | Recurrent ischaemic episodes | Often sickle cell | Prevent episodes |
Causes
- Sickle cell disease: the most common cause in children.
- Drugs: intracavernosal injections, PDE5 inhibitors (rarely), antipsychotics, trazodone, alpha-blockers, cocaine, cannabis.
- Blood disorders: leukaemia, thalassaemia.
- Trauma: non-ischaemic priapism.
- Neurological: spinal cord injury.
Ischaemic or not?
Ischaemic: aspirate now
Non-ischaemic: urology, Doppler, observation
Management of ischaemic priapism
- Recognise and call urologyTime matters.
- AnalgesiaIV analgesia or dorsal penile nerve block.
- Cavernosal blood gasConfirms ischaemia.
- Aspiration19–21G needle into one corpus cavernosum at the side of the shaft (avoid the top and the bottom midline). Aspirate until bright red blood.
- IrrigationWith saline if needed.
- Intracavernosal phenylephrineIf aspiration fails, with BP and ECG monitoring.
- FailsSurgical shunt by urology.
In sickle cell disease, start fluids, oxygen and analgesia and contact haematology, but don't delay aspiration.
Investigations
| Test | Why |
|---|---|
| Cavernosal blood gas | Ischaemic or not |
| FBC, reticulocytes | Sickle cell, leukaemia |
| Haemoglobin electrophoresis | If sickle cell status unknown |
| Urine drug screen | Cocaine and other drugs |
| Penile Doppler ultrasound | Non-ischaemic priapism (fistula) |
Treatment
After the episode
- Explain the risk of erectile dysfunction, which rises with time.
- Stop or change causative drugs.
- Sickle cell: haematology follow-up for prevention.
- Teach to come immediately if it happens again.
Common mistakes
- Waiting for an erection to "settle" past 4 hours.
- Ice packs and exercise as the only treatment.
- Aspirating a painless trauma-related priapism without a gas first.
- Giving phenylephrine without monitoring.
- Forgetting to ask about drugs and sickle cell.
Frequently asked questions
When is priapism an emergency?
A painful, rigid erection lasting over 4 hours is ischaemic priapism and is a urological emergency.
How do you tell ischaemic from non-ischaemic priapism?
Ischaemic priapism is painful and rigid with dark cavernosal blood that is acidotic and low in oxygen. Non-ischaemic is painless, partly rigid and has bright red blood.
What is the first treatment for ischaemic priapism?
Aspiration of blood from the corpus cavernosum, then intracavernosal phenylephrine if it doesn't settle.
What is the commonest cause of priapism in children?
Sickle cell disease.
Test yourself
Exam-style questions on this guide, from our two question banks. Choose an answer to see why each option is right or wrong.
1. A man with sickle cell disease has a painful rigid erection for 6 hours. What type is this?
Answer: Ischaemic priapism. Painful, rigid, over 4 hours: urological emergency.
- Normal erection: No.
- Peyronie's disease: No.
- Non-ischaemic priapism: Painless, after trauma.
- Paraphimosis: No.
2. What does the corporal blood gas show in ischaemic priapism?
Answer: Low pH and low oxygen. Trapped blood becomes acidotic and hypoxic.
- High pH: No.
- Normal pH and high CO₂: No.
- Normal arterial values: Non-ischaemic.
- High oxygen: No.
3. Which drug is injected into the corpora after aspiration for ischaemic priapism?
Answer: Phenylephrine. Alpha-agonist causes detumescence, under monitoring.
- Heparin: No.
- Sildenafil: Causes priapism.
- Adrenaline: Not the standard.
- Atropine: No.
4. A 22-year-old with sickle cell disease has a painful rigid erection for 6 hours; cavernosal blood gas is dark, hypoxic and acidotic. What is the first intervention?
Answer: Aspiration ± phenylephrine. Ischaemic (low-flow) priapism: painful rigid erection > 4 hours, dark hypoxic cavernosal blood — emergency (fibrosis, erectile dysfunction). Causes: sickle cell disease (commonest in children), intracavernosal drugs, antipsychotics, trazodone, cocaine, leukaemia. Management: corporal aspiration ± saline irrigation, intracavernosal phenylephrine (α-agonist; monitor BP/HR), then surgical shunt; treat sickle crisis concurrently (fluids, oxygen, analgesia, exchange transfusion). Non-ischaemic (high-flow): painless, after trauma (arterial fistula) — conservative/embolisation.
- Observe for 24 hours: Waiting causes erectile tissue damage.
- Oral sildenafil dose: Sildenafil worsens priapism.
- Ice packs and analgesia: Ice packs are inadequate after 4 hours.
5. A young man has a painful leg ulcer and recurrent bone pain crises. His blood film shows Howell–Jolly bodies and sickle cells. Why are Howell–Jolly bodies present?
Answer: Autosplenectomy. In sickle cell disease, repeated splenic infarcts shrink the spleen (autosplenectomy) by late childhood. Without a spleen, nuclear remnants (Howell–Jolly bodies) are not removed from red cells. Patients are at risk from encapsulated bacteria and need vaccines and penicillin prophylaxis. Leg ulcers are common.
- Iron deficiency: Causes microcytic cells; not Howell–Jolly bodies.
- Lead poisoning: Causes basophilic stippling.
- Vitamin B12 deficiency: Causes megaloblasts and hypersegmented neutrophils.
- Thalassaemia trait: Causes target cells and microcytosis.
6. An adult with sickle cell disease has Howell-Jolly bodies on the blood film and recurrent pneumococcal infections. Why?
Answer: Functional asplenia. In sickle cell disease, repeated vaso-occlusion infarcts the spleen; by late childhood it is usually small and fibrotic (autosplenectomy). Loss of splenic function removes clearance of red cell inclusions (Howell-Jolly bodies—nuclear remnants) and impairs opsonisation and IgM responses against encapsulated organisms (Streptococcus pneumoniae, Haemophilus influenzae type b, Neisseria meningitidis), and Salmonella osteomyelitis is also characteristic. Prevention: vaccination, daily penicillin prophylaxis in childhood, and hydroxyurea (raises HbF). In young children, splenic sequestration crisis can cause sudden severe anaemia with an enlarging spleen.
- Iron deficiency: Not the cause.
- Antibodies from sickle cells: Not correct.
- Parvovirus marrow failure: Causes aplastic crisis, not inclusions.
- Excess transfusion: Not the cause.
References and dose sources
- BAUS
- EAU — sexual and reproductive health guidelines
- Lidocaine (lignocaine) dosing: Drugs.com: Lidocaine dosage (see also our lidocaine (lignocaine) dose page)
- Morphine dosing: Drugs.com: Morphine dosage (see also our morphine dose page)
International guidance is linked where it reflects good practice. Where your hospital’s protocol differs, follow your hospital.