Priapism



Background

  • When an erection is abnormally prolonged it is called priapism
  • It is caused by obstruction of the venous drainage of the penis or trauma causing a high-flow state (like a fistula)
  • Common causes include:
    • Sickle cell disease
    • Leukaemia in children
    • Intra corporeal injections used to induce erections in patients undergoing treatment for erectile dysfunction
    • It can also be drug related (heparin, phenothiazines) or idiopathic
  • At presentation there is usually considerable pain due to the ischaemia of the erectile tissue
  • Impotence occurs in up to 50% Priapism is a urological emergency
  • Call for help now, bloods for FBC, ± Hb electrophoresis, ± drug screen
  • Record whether the glans is or is not swollen, examine abdomen and complete rectal examination
  • Try to establish whether this is high flow (non-ischaemic) or low flow (ischaemic) priapism.
    • Low flow = commonest, painful priapism, glans and spongiosum are soft
    • High flow = rare, usually trauma related, painless, glans engorged, cavernous blood pH> 7.25, PO2 > 60mmHg
  • If sickle cell suspected, involve haematologists first. Treatment involves analgesia, Hydroxyurea, hydration, alkalinisation, and exchange transfusion, the aim being to decrease HbS concentration by 30% (beware ASPEN syndrome)

In ischaemic - "low flow" - priapism

  • Initial intervention may utilize therapeutic aspiration (with or without irrigation) or intracavernous injection of sympathomimetic (Phenylephrine has lowest chance of systemic side effects)
  1. Cardiac monitoring applied
  2. Local or dorsal penile nerve block
  3. Inject along shaft of penis at 2 and 10 o' clock
  4. Aspirate 30 mls of blood each side
  5. Send blood for gas analysis
  6. Add 10 mg (usually 1.0 mL) of Phenylephrine to 499 mL of saline 0.9%, yielding a solution with 20 mcg/mL
  7. Adult Dose 100-500 mcg per dose, up to 10 doses over an hour; use 10-20 mL of 20 mcg/mL solution by intracavernous injection
  8. Lower concentrations in smaller volumes should be used in those with severe cardiovascular disease

In non-ischaemic - "high flow" - priapism

Corporeal aspiration has only a diagnostic role. Aspiration with or without injection of sympathomimetic agents is not recommended as treatment.

  • The initial management of non ischaemic priapism should be observation. 
  • Immediate invasive interventions (embolization or surgery) can be performed at the request of the patient

Management

Anatomy

Approach



Content by Dr Íomhar O' Sullivan. Last review Dr ÍOS 13/12/21.