Priapism
BASICS
- Definition: Penile (or rarely clitoral) erection lasting >4 hours, unrelated to sexual stimulation.
- Classification:
- Ischemic (low-flow, veno-occlusive): 95% of cases; emergent, painful, risk of tissue necrosis.
- Nonischemic (high-flow, arterial): Less common, often painless, not emergent.
- Stuttering (recurrent ischemic): Episodic, short-lived, may not need intervention.
- Malignant: Rare, usually due to metastasis (bladder, prostate, rectosigmoid, renal).
EPIDEMIOLOGY
- Incidence: ~5.3/100,000 men/year
- Age: Shift toward >40 years
- Race: 61% African American (SCD association)
- Children: SCD is the most common cause (63%), others include leukemia, trauma, drugs.
ETIOLOGY AND PATHOPHYSIOLOGY
- Anatomy: 2 corpora cavernosa (erection), 1 corpus spongiosum (glans).
- Ischemic priapism: Decreased venous outflow β blood stasis, hypoxia, acidosis, compartment syndrome β tissue necrosis/fibrosis if >24 hr.
- Mechanisms: NO/cGMP dysregulation, RhoA/Rho kinase, adenosine, opiorphin.
- Nonischemic: Increased arterial inflow, usually due to trauma (arteriocavernous fistula).
- Causes:
- Ischemic: Idiopathic (50%), SCD/hemoglobinopathies, leukemia, drugs (erectile agents, Ξ±-blockers, antidepressants, antipsychotics, antihypertensives, hormones, anticoagulants), infections, neurogenic, neoplastic, metabolic, recreational drugs.
- Nonischemic: Penile/perineal trauma, acute spinal injury.
- Risk Factors: SCD (lifetime risk 29β42%), dehydration, prior priapism.
GENERAL PREVENTION
- Avoid dehydration (esp. SCD)
- Avoid causative drugs, trauma, excessive stimulation
COMMONLY ASSOCIATED CONDITIONS
- SCD (most important)
- Drug abuse, G6PD deficiency, leukemia, neoplasm
DIAGNOSIS
History
- Prior episodes, pain degree, duration, trauma, urination issues, hemoglobinopathy history, drug use
Physical Exam
- Ischemic: Fully erect, painful, rigid corpora cavernosa; flaccid glans/corpus spongiosum.
- Nonischemic: Partially erect, nontender, semirigid corpora; flaccid glans/spongiosum.
- Assess for trauma, gangrene, prosthesis, underlying disease.
Diagnostic Tests
- Labs: CBC (reticulocyte), sickling test, hemoglobin electrophoresis, coag profile, urinalysis/toxicology.
- Corporal Blood Gas: Ischemic: pH <7.25, pO2 <30 mmHg, pCO2 >60 mmHg.
- Imaging:
- Doppler US: Ischemic = low flow; Nonischemic = high flow
- MRI: Consider if >48β72 hr (to assess necrosis/prosthesis candidacy)
- Arteriography: For nonischemic fistula/pseudoaneurysm
TREATMENT
Ischemic Priapism (Emergent)
- Initial: Attempt ejaculation, vigorous exercise, ice/cold bath (do not delay definitive therapy!)
- Definitive:
- Aspiration of cavernosal blood (large-bore needle)
- Intracavernosal phenylephrine: 200 ΞΌg q3β5min (max 1,500 ΞΌg) with BP monitoring
- If failure: Shunt procedures (distal/proximal)
- SCD: IV hydration, O2, exchange transfusion only after failed initial therapy
- Analgesia: Opioids PRN
- Second Line: Intracavernosal etilefrine, methylene blue, or epinephrine
- Refer: Urology (ALL cases)
Nonischemic Priapism
- Not emergent: Observe, ice, local compression
- If persistent: Selective arterial embolization or surgery
Stuttering Priapism
- Acute attacks: Manage as ischemic
- Prevention:
- Adrenergic agonists (pseudoephedrine, etilefrine)
- Androgen suppression (antiandrogens, finasteride, ketoconazole)
- PDE5 inhibitors (sildenafil)
- Digoxin, terbutaline, gabapentin, baclofen, hydroxyurea
SURGERY/PROCEDURES
- Shunt procedures: Distal (Ebbehoj, Winter, T, Al-Ghorab), proximal (Quackles, Sacher), venous (Grayhack, Barry)
- Immediate penile prosthesis: For failed medical/surgical treatment or tissue necrosis (early surgery avoids fibrosis/curvature)
- Nonischemic: Selective embolization, surgical ligation if needed
PROGNOSIS
- Ischemic >24 hr: Up to 90% risk permanent ED
- Detumescence may take weeks if prolonged priapism
- Recurrence or stuttering common in SCD
COMPLICATIONS
- Erectile dysfunction, tissue necrosis, mental health issues (depression, suicidality)
- Avoid SSRIs, trazodone, fluoxetine, citalopram in at-risk patients
ICD-10 CODES
- N48.30 Priapism, unspecified
- N48.31 Priapism due to trauma
- N48.39 Other priapism
CLINICAL PEARLS
- Priapism >24 hr likely causes permanent sexual impairment.
- In children, especially SCD, address both acute episode and underlying disease.
- Always distinguish ischemic (emergent) from nonischemic by history, exam, cavernosal blood gas, and imaging.
- Immediate urologic evaluation for ischemic priapism is essential.