Priapism – Complete Explanation
Definition
Priapism is a prolonged, persistent penile erection lasting more than 4 hours that occurs without sexual stimulation and does not subside after ejaculation. It is a urological emergency because prolonged erections can cause permanent tissue damage and erectile dysfunction.
Types of Priapism
- Ischemic (Low-Flow) Priapism – Most Common & Dangerous
- Caused by blocked venous outflow
- Blood becomes trapped and deoxygenated in the penis
- Very painful
- Penis is rigid, but the tip (glans) is often soft
Why it’s dangerous:
- Lack of oxygen leads to tissue ischemia and necrosis
- After 6–8 hours → high risk of permanent erectile dysfunction
- Non-Ischemic (High-Flow) Priapism
- Caused by uncontrolled arterial inflow
- Usually follows perineal or penile trauma
- Less painful
- Penis is partially rigid
- Not an immediate emergency but still needs evaluation
- Stuttering (Recurrent) Priapism
- Repeated episodes of ischemic priapism
- Common in patients with sickle cell disease
- Episodes resolve but recur frequently
Causes of Priapism
Blood Disorders
- Sickle cell disease (most common in children)
- Leukemia
- Thalassemia
Medications
- Erectile dysfunction drugs (sildenafil, tadalafil)
- Antidepressants (trazodone, SSRIs)
- Antipsychotics
- Blood thinners
- Recreational drugs (cocaine, marijuana, alcohol)
Trauma
- Pelvic or perineal injury (especially for high-flow priapism)
Neurologic Conditions
- Spinal cord injury
- Brain tumors
Idiopathic
- No identifiable cause
Pathophysiology (How It Happens)
Normal Erection
- Increased arterial inflow
- Venous outflow decreases temporarily
- After ejaculation → blood drains
Ischemic Priapism
- Venous outflow remains blocked
- Blood becomes hypoxic
- Leads to:
- Acidosis
- Edema
- Tissue necrosis
Non-Ischemic Priapism
- Arterial blood flows uncontrollably into erectile tissue
- Blood remains oxygenated
