Priapism Flashcards
What is priapism?
Unwanted painful erection of the penis not associated with sexual desire lasting for >4 hours.
Epidemiology
Low in most Western countries.
Higher in countries with high prevalence of haemoglobinopathies like Sickle cell disease.
Pathophysiology
Ischaemic priapism is considered a urological emergency.
Blood stays within the corpus cavernosa, glans and corpus spongiosum are usually unaffected.
Classifications
High flow aka non-ischaemic priapism
Low flow aa ischaemic priapism
Explain high flow.
Caused by unregulated cavernous arterial inflow.
Arterial blood rapidly enters the corpus cavernosum more quickly than it can be drained.
This is often associated with trauma as an underlying cause and can be triggered by sexual strimulation.
Explain low flow priapism
Veno-occlusive in nature with prolonged venous stasis.
This is by blockage to venous drainage of the corpus cavernosum and can cause ischaemia, fibrosis and impotence.
Explain stuttering priapism.
Aka recurrent or intermittent priapism.
Repetitive and painful episodes of prolonged erections with intervening periods of detumescence and is often self-limiting.
Episodes are shorter, but can cause major ischaemic episode.
Causes
Usually idiopathic
Non-ischaemic causes = penile or perineal trauma or spinal cord injury
Ischaemic causes:
Iatrogrenic by intracavernosal drug therapy for impotence like papaverine or alprostadil
Sickle cell disease
Leukaemia or thalassemia
Pelvic malignancy
Antipsychotics, anticoagulants and antidepressants can also cause it.
Clinical features
Ongoing and unwanted erection in absence of sexual desires >4h
In ischaemic cases the erection is painful and rigid
In non-ischaemic it is typically painless and erection is not fully rigid
Investigations
Corporeal blood gas (into penis) should be done
This determines whether it is ischaemic or non-ischaemic
Routine bloods should be done with FBC, CRP, ESR, coag screen, bone profile, hb electrophoresis +/- drug screen.
In non-ischaemic investigation of potential spinal injury should be done and colour doppler USS
Corporeal blood gas findings in ischaemic vs non-ischaemic.
Initial management
Corporeal aspiration whch achieves detumescence in around 30% of cases
Ice packs, physical exertion and masturbation have previously been advocated but are now deemed ineffective.
If there is no response from aspiration, intracavernosal injection of a sympathomimetic agent like phenylephrine can be tried.
Explain corporeal aspiration
Required to obtain corporeal blood gas as well.
A large bore needle is inserted into the lateral edge of one corpus cavernosum.
After diagnostic aspiration several rounds of further aspiration and wash-out can be perfomed to achieve detumescence.
Around 10-15ml of static blood should be aspirated and replaced with normal saline until the aspirate is bright red.
Surgical management
If nothing works a prompt surgical shunt can be inserted into corpus cavernosa and glans.
It can be between erect corpora cavernosa and either glans penis, corpus spongiosum or saphenous vein.
Achieves subsidisition in around 70% of cases.
Can lead to ED however
Prognosis
Around 90% of cases with priapism for >24 hours do not regain ability to have intercourse again.
Penile prosthesis insertion may be considered
