Ischemic priapism
A rigid, painful erection past four hours is a compartment syndrome of the penis. One needle is both the diagnosis and the start of treatment — and the corpora are dying while the patient sits in the waiting room, often too embarrassed to say why.
The one-liner
Treat any painful erection >4 h as ischemic until the corporal blood gas says otherwise. Aspirate ± phenylephrine at the bedside before anything else; the gas confirms it and the aspiration begins fixing it.
Ischemic priapism is a compartment syndrome wearing an embarrassing disguise. The corpora cavernosa are a closed venous reservoir in stasis, the tissue is turning acidotic and hypoxic by the hour, and the smooth muscle starts dying within hours of severe ischemia. The clock is quieter than torsion’s, but it is just as real.
The frame
A painful, sustained, rigid erection past 4 hours is ischemic priapism until a blood gas proves otherwise. Classically the glans and corpus spongiosum stay soft — the rigidity is corpora cavernosa only. Beyond roughly 24 hours, the muscle damage is usually permanent regardless of whether you achieve detumescence, which is why time is the whole game.
What everyone gets wrong
Treating the aspiration as a diagnostic step you do after imaging or a consult. The cavernosal aspirate is both the test and the first treatment— you do it in the ED, now. A venous-bad gas confirms ischemia and you’ve already started decompressing the compartment.
One needle answers the question
Aspirate corporal blood and send a gas. The numbers that define ischemia:
- pH < 7.25
- pO₂ < 30 mmHg
- pCO₂ > 60 mmHg
That is venous-gas-bad: a closed compartment in stasis. A non-ischemic (high-flow) priapism — usually an arterial fistula after perineal trauma — gives an arterial-looking gas, is not painful, and is not an emergency: observe, then selective embolization through IR.
The bedside sequence
- Aspirate10–20 mL from each corpus through a 19–21 G lateral cavernosal needle.
- Phenylephrine100–500 mcg in 1 mL saline intracavernosally, every ~5 minutes until detumescence or roughly 1 mg total. Keep it intracavernosal and watch the blood pressure.
- Not down? Repeat aspiration ± phenylephrine for about an hour.
- Still rigid? Distal shunt — Winter, Ebbehoj, or T-shunt.
- Refractory or very prolonged? Proximal shunt (Quackels/Sacher); past ~36 hours, early penile prosthesis is a legitimate path.
The sickle-cell trap
In sickle-cell priapism, do not skip the aspiration sequence. Hydration, analgesia, and exchange transfusion are adjuncts, not replacements — aspirate while the systemic care is mobilizing.
And remember that stuttering priapism is still priapism: each acute episode is managed as ischemic. Prevention — PDE5i scheduling, hormonal therapy — is a separate, outpatient conversation.
If you remember one thing
The patient who waited out of embarrassment has already spent some of the clock. Don’t spend more of it arranging imaging. The needle is the diagnosis and the treatment in the same motion.