Priapism is a medical condition defined by a prolonged, often painful erection that occurs without sexual interest or stimulation. When this condition arises in individuals who have sustained a Spinal Cord Injury (SCI), it points to a specific disruption in the body’s control systems. The connection between SCI and priapism highlights a complex neurological and vascular failure that demands immediate medical attention to prevent permanent damage.
Understanding Priapism: Definition and Types
Priapism is broadly classified into two main categories based on the flow of blood within the penile tissues. The most frequent and dangerous form is Ischemic priapism, often referred to as low-flow priapism. This occurs when venous drainage from the penis is obstructed, leading to a build-up of stagnant, poorly oxygenated blood within the corpora cavernosa. Ischemic priapism is typically painful and constitutes a urological emergency because the lack of oxygen can rapidly cause tissue damage.
The second type is Non-Ischemic priapism, also known as high-flow priapism, which is less common and generally not painful. This type results from an unregulated, excessive arterial blood flow into the penis, often due to an injury that creates an abnormal connection, or fistula, between an artery and the erectile tissue. Because the blood is still oxygenated, the risk of immediate tissue necrosis is lower than with the ischemic type. A third category, recurrent or stuttering priapism, involves repetitive, short-lived episodes, and shares the same underlying causes as the ischemic form.
The Specific Role of Spinal Cord Injury
Spinal Cord Injury (SCI) can directly cause priapism by profoundly altering the balance of the Autonomic Nervous System (ANS) that controls erectile function. The ANS includes the sympathetic system, which controls detumescence (flaccidity), and the parasympathetic system, which controls erection. Normally, these two systems work in concert, with signals originating in the brain maintaining overall control.
Following an SCI, especially with complete lesions, the descending signals from the brain that regulate the sympathetic nerves are interrupted. This loss of supraspinal control leads to a functional “sympathetic blunting” below the level of the injury. The sympathetic nerves typically cause the penile smooth muscle to contract, allowing blood to drain and the erection to subside.
With the sympathetic “off-switch” disabled, the parasympathetic system’s signals, which promote blood flow into the erectile tissue, can become unchecked. This results in an uncontrolled, sustained relaxation of the cavernous smooth muscle and an increase in arterial blood flow into the penis. This mechanism usually causes the high-flow, Non-Ischemic type of priapism in the acute phase following a traumatic SCI.
The resulting priapism is a reflex action mediated solely by the spinal cord segments that control the pelvic organs, without the necessary inhibitory input from the brain. While acute SCI-related priapism is often high-flow and may resolve spontaneously within hours, it can rarely progress to the more dangerous low-flow type due to stasis and clotting. Any prolonged erection in an SCI patient must be immediately assessed.
Acute Treatment Strategies
The management of priapism in any patient, particularly one with SCI, follows a time-sensitive, stepwise approach aimed at achieving detumescence and preserving erectile function. The first step is determining the type of priapism, often using a corporal blood gas analysis. This test measures the oxygen, carbon dioxide, and pH of blood drawn directly from the corpora cavernosa, quickly distinguishing between oxygen-poor ischemic blood and oxygen-rich non-ischemic blood.
For Ischemic priapism, the first-line treatment involves mechanical and pharmacological intervention. The urologist performs aspiration and irrigation, which involves inserting a needle into the corpus cavernosum to remove the stagnant, deoxygenated blood and irrigate the area with saline solution. This process helps to relieve the pressure and metabolic distress on the tissue.
Simultaneously, a sympathomimetic agent, most commonly phenylephrine, is injected directly into the erectile tissue. Phenylephrine is an alpha-adrenergic agonist that mimics the body’s natural sympathetic response by causing the smooth muscle in the penis to contract, allowing blood to drain. Doses are repeated every few minutes, with careful monitoring of the patient’s heart rate and blood pressure, until the erection resolves.
If these non-surgical methods fail after a reasonable period, usually within about an hour, surgical intervention is required. A distal corporoglanular shunt is created, such as a Winter, Al-Ghorab, or T-shunt. This forms a small channel to divert blood flow from the corpora cavernosa into the glans penis, allowing it to drain back into the systemic circulation. This procedure is necessary to relieve the ischemic state and prevent permanent tissue death.
Long-Term Implications and Follow-up Care
Priapism carries potential long-term consequences even after successful acute management. The most significant concern is Erectile Dysfunction (ED), which results from oxygen deprivation causing irreversible damage to the smooth muscle and nerves within the corpora cavernosa. The extent of ED is directly related to the duration of oxygen deprivation.
Another potential outcome is penile fibrosis, where damaged tissue is replaced by inelastic scar tissue, leading to shortening or curvature. For individuals with chronic SCI, managing the risk of priapism recurrence is a focus of long-term care. Preventative measures for recurrent priapism may involve oral medications like baclofen, which reduce the frequency and duration of unwanted erections.
Multidisciplinary care is necessary to manage the physical and psychological toll of this condition. This involves urologists for monitoring and treating ED, potentially through the placement of a penile prosthesis. Psychologists or counselors also assist with emotional and sexual health adjustments following the event. Regular monitoring ensures that any subsequent episodes are caught early.