Priapism

Prolonged unwanted erection (> 4 hours), often painful and not associated with sexual arousal

Aetiology

  • Intracorporeal injection for ED e.g. papavarine
  • Trauma (penile/perineal)
  • Haematological dyscrasias e.g. sickle cell
  • Neurological conditions
  • Idiopathic

Pathophysiology

  • Ischaemic (veno-occlusive or low-flow)
    • Vascular stasis in penis and decreased venous outlfow - a true compartment syndrome
    • Corposa cavernosa are rigit and tender, penis often painful
  • Non-ischaemic (less urgent)
    • Traumatic distuption of penile vasculature results in unregulated blood entry and filling of corpora
    • Fistula formation betweenc cavernous artrery and lacinar spaces allows blood to bypass the normal helicine arteriolar bed

Investigations

  • Aspirate blood from corpus cavernosum
    • Dark blood, low O2 and high CO2 in low-flow
    • Normal arterial blood in high-flow
  • Colour duplex USS
    • Minimal or absent flow in cavernosal arteries in low-flow
    • Normal to high flow in non-ischaemic priapism

Management

Ischaemic

  • Aspiration +/- irrigation with saline
  • If fails to resolve - injection of ⍺-agonist e.g. phenylephrine
  • If fails to resolve - surgical shunt
  • Ischaemic priapism > 48-72 hours unlikely to respond to intracavernosal treatment
  • For very delayed presentation, may even consider immediate placement of a penile prosthesis

Non-ischaemic

  • Observe, may resolve spontaneously
  • Selective arterial embolization with non-permanent materials