Priapism

Priapism is a medical condition characterised by a prolonged and often painful erection lasting for hours in the absence of sexual stimulation. It is classified into three types: ischaemic (low-flow), nonischaemic (high-flow), and recurrent ischaemic (intermittent). The most common type is ischaemic priapism. This condition can lead to permanent damage if not treated promptly.

Classification

Priapism can be broadly classified into three categories:

1. Ischaemic (low-flow): This type involves inadequate drainage of blood from the penis, leading to a painful and persistent erection. Most cases of priapism fall under this category.
2. Nonischaemic (high-flow): This is usually less painful and caused by unregulated arterial blood flow into the penis, often due to trauma.
3. Recurrent ischaemic (intermittent): Characterised by repeated episodes of prolonged erections.

Priapism is rare, occurring in about 1 in 20,000 to 1 in 100,000 males per year.

Signs and Symptoms

Ischaemic priapism typically presents with the following symptoms:

• Persistent erection lasting more than four hours.
• Painful erection.
• Hard shaft with a soft glans penis.

Nonischaemic priapism usually presents as a painless, partially stiff erection. In women, a rare condition known as clitoral priapism can occur, associated with persistent genital arousal disorder (PGAD).

Complications

Prolonged ischaemic priapism can result in significant complications due to oxygen deprivation in penile tissue, such as:

• Erectile dysfunction.
• Penile disfigurement.
• In severe cases, penile gangrene.

Causes

Common causes of ischaemic priapism include:

• Sickle cell disease.
• Medications (e.g., antipsychotics, SSRIs, blood thinners, prostaglandin E1).
• Recreational drugs (e.g., cocaine).
• Blood disorders (e.g., leukaemia, multiple myeloma).

High-flow priapism can be caused by:

• Trauma to the penis or perineum.
• Use of anticoagulants and antihypertensives.
• Hormonal treatments.

Diagnosis

Diagnosis is primarily based on the clinical history and physical examination. Blood gas analysis and colour Doppler ultrasound can help differentiate between the types of priapism.

Ultrasonography

Penile ultrasonography with Doppler is the preferred imaging method due to its noninvasive nature and high sensitivity. It helps in diagnosing priapism and distinguishing between low-flow and high-flow types.

Treatment

Immediate medical evaluation is recommended for erections lasting more than four hours. Treatment varies based on the type of priapism.

Nonischaemic Priapism

• Cold packs and compression: Initial treatment to reduce blood flow.
• Pseudoephedrine: An alpha-agonist that promotes venous outflow by constricting the smooth muscle of the corpora cavernosa.

Ischaemic Priapism

• Aspiration: Removal of blood from corpus cavernosum.
• Medications: Phenylephrine may be injected into the corpus cavernosum if aspiration is insufficient. Patients should be monitored for side effects like hypertension and arrhythmias.
• Surgery: Various shunt procedures (e.g., Winter's and Quackel's shunts) may be used if conservative measures fail. Early penile prosthesis implantation may be considered to prevent fibrosis and penile shortening.

Sickle Cell Anaemia

• Initial Treatment: Intravenous fluids, pain management, and oxygen therapy.
• Advanced Treatment: Exchange transfusion if standard treatments are ineffective.

History and Terminology

The term priapism is derived from Priapus, the Greek god of fertility, often depicted with an exaggerated phallus. Historically, persistent semi-erections and intermittent prolonged erections were sometimes referred to as semi-priapism.

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Self-assessment MCQs (single best answer)

What is the most common type of priapism?

Which condition is commonly associated with ischaemic priapism?

What is a common symptom of nonischaemic priapism?

Which imaging method is preferred for diagnosing priapism?

What is the primary treatment for nonischaemic priapism?

What is the first-line treatment for ischaemic priapism?

Prolonged ischaemic priapism can lead to:

Which of the following medications is commonly used to treat ischaemic priapism?

In cases of sickle cell anaemia causing priapism, which treatment may be considered if standard treatments are ineffective?

The term priapism is derived from: