Priapism and Sickle Cell Disease

Reviewed by: HU Medical Review Board | Last reviewed: January 2021

Men with sickle cell disease (SCD) can experience a complication called priapism. This is an unwanted erection, which may last for any amount of time. It happens when blood flow out of the penis is blocked by sickled red blood cells.

Most episodes can be managed at home. However, erections lasting longer than 4 hours are a medical emergency. If you experience recurring episodes of priapism, talk to your doctor about preventing and managing the condition.

What is priapism?

Priapism is a prolonged and unwanted erection. Priapism is categorized as either low blood flow or high blood flow. Low-flow priapism (also called ischemic or veno-occlusive priapism) makes up more than 95 percent of priapism cases in people with SCD.1

Priapism episodes can last for any duration of time. Erections occurring for longer periods of time increases the risk for permanent damage. Over time, this can cause damage to the blood vessels of the penis and lead to erectile dysfunction. Erectile dysfunction is also called impotence and refers to the inability to have an erection. Erections lasting 4 or more hours are a medical emergency.2,3

Most people affected by priapism experience brief, repeated episodes that last for a few minutes up to 3 hours. This is called stuttering priapism, and episodes are usually painful.4,5

Why does sickle cell disease cause this?

Almost half of men with SCD experience priapism. Priapism can affect men with any type of SCD, but it is most common in sickle cell anemia (HbSS). About 30 percent of men with SCD who have stuttering priapism develop erectile dysfunction. The first episode usually occurs as a teenager after puberty.5-9

SCD causes priapism when sickled red blood cells block blood flow out of the penis. This blocks blood from circulating normally in the penis and leads to low oxygen levels, tense rigidity, and pain. Over time, this leads to permanent injury and inflammation, causing erectile dysfunction.2,3

The biological process that reduces erections is also impaired in people with SCD. The quick bursting of sickle cells releases free hemoglobin, which reduces a chemical called nitric oxide. When nitric oxide levels are low, the proteins that contract muscles to stop erections cannot work.10,11

Some triggers for priapism episodes may include:2,5,9

  • Going to sleep, sleeping, or waking up
  • Sexual intercourse
  • Pulmonary hypertension (high blood pressure in the lung)
  • Leg ulcers
  • Fever or dehydration
  • Certain medications
  • Drug and alcohol use

Men with priapism may be anxious about sex because of the risk of causing an episode of priapism.5

What are the symptoms?

The defining symptom of priapism is an unwanted erection. The erection is usually painful, and other sites of pain may be present. However, episodes of priapism are usually not linked to other SCD complications, such as stroke or acute chest syndrome.

The duration of the erection varies. Typical episodes last for 1 to 2 hours, but many men have shorter episodes or major episodes lasting longer than 4 hours. The frequency also varies, with some men experiencing only 1 episode and others having an episode weekly.9

How is it prevented and treated?

Doctors should discuss priapism during routine healthcare and education for boys and men with SCD. Many people are uncomfortable starting discussions about their sexual health. Others may not know that priapism is a complication of SCD or that the consequences of priapism can be severe.2,12

Priapism episodes are often prevented by:2,13

  • Avoiding infections and dehydration
  • Avoiding some medicines, such as those that block alpha-adrenergic receptors (drugs that block the effect of sympathetic nerves on blood vessels)
  • Treatment with hydroxyurea or sildenafil
  • Regular use of drugs that stimulate alpha-adrenergic receptors
  • Regular blood transfusions
  • Hormonal therapies

The approach you use depends on your specific situation. If you experience priapism, talk to your doctor about how to prevent further episodes.

Brief episodes of priapism are managed at home. Your doctor can give specific instructions for treating priapism at home. This will usually include:2,8

  • Drinking plenty of fluids
  • Using over-the-counter pain medications
  • Exercise
  • Warm or cold compresses
  • Masturbation with ejaculation

An erection lasting longer than 4 hours is a medical emergency. It is treated in the emergency room with intravenous hydration, strong pain medications, and additional tests. Additional procedures may be done, such as:2,6

  • Drawing out blood from the penis
  • Injecting drugs that stimulate alpha-adrenergic receptors
  • Surgery to help drain blood

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