Priapism

Priapism is a persistent penile erection lasting 4 hours or longer that is unrelated to or persists beyond sexual stimulation.

The critical distinction is:

Ischaemic priapism

Low flow, painful, rigid corpora.

This is a urological emergency.

Nonischaemic priapism

High flow, usually after arterial trauma.

Penis is partially rigid and generally painless.

This is not usually an immediate emergency.

Stuttering priapism

Recurrent episodes of ischaemic priapism that resolve spontaneously but recur.

Sickle cell disease is an important cause, particularly in younger men.

Ischaemic

• Severe penile pain
• Fully rigid corpora cavernosa
• Relatively soft glans
• Duration beyond 4 hours

Nonischaemic

• Partial erection
• Minimal pain
• History of perineal or penile trauma
• Persistent arterial inflow

If clinical type is uncertain, aspirate cavernosal blood.

Ischaemic blood gas

Typically:

• PO₂ below 30 mmHg
• PCO₂ above 60 mmHg
• pH below 7.25

Blood is dark.

Nonischaemic blood gas

Approximates normal arterial blood.

Penile Doppler ultrasound identifies:

• Minimal cavernosal arterial flow in ischaemic disease
• High flow arterial fistula in nonischaemic disease

Ischaemic priapism

Do not delay treatment while waiting for the underlying cause to be fully investigated.

Use local penile anaesthesia.

Aspiration

Insert a 16 or 18G needle or cannula into the lateral proximal corpus cavernosum.

Aspirate dark blood until brighter blood appears.

Irrigate with 0.9% saline as necessary.

Phenylephrine

Inject:

Phenylephrine 200 micrograms intracavernosally every 3 to 5 minutes

up to a maximum total:

1 mg within 1 hour.

Monitor:

• Blood pressure
• Pulse

Use lower doses in patients with significant cardiovascular disease.

Phenylephrine plus aspiration is the standard first line intervention and resolves most early cases.

Sickle cell disease

Treat penile ischaemia exactly as other ischaemic priapism.

Simultaneously provide:

• Analgesia
• Hydration when dehydrated
• Oxygen when hypoxaemic
• Haematology management

Do not delay aspiration and phenylephrine while arranging exchange transfusion. Exchange transfusion is not primary penile treatment.

Surgical shunt

If aspiration and repeated phenylephrine fail, perform a distal shunt first.

Options include:

• Winter shunt
• Ebbehoj shunt
• Al Ghorab shunt

Add corporal tunnelling when required.

Proximal shunts are now used less commonly.

Priapism beyond 36 to 48 hours

Prolonged ischaemia produces extensive corporal smooth muscle necrosis and a very high likelihood of permanent erectile dysfunction.

In priapism persisting beyond approximately 48 hours, early penile prosthesis insertion can be considered rather than repeated ineffective shunts, particularly when smooth muscle necrosis is established.

Nonischaemic priapism

Initial treatment can be observation because tissue is oxygenated.

If persistent and troublesome:

Perform selective arterial embolisation of the fistula.

Avoid aspiration and phenylephrine as routine treatment because the pathophysiology is uncontrolled arterial inflow rather than venous trapping.