What Causes Paraphimosis?

Paraphimosis is a urologic emergency, which results exclusively in uncircumcised or partially circumcised penis. It occurs when the foreskin in these males remains retracted for an extended period of time and there is difficulty in its replacement to normal anatomical position. The extended retraction of the foreskin leads to venous occlusion, edema and arterial occlusion. This progressive edema of the foreskin owing to venous and arterial occlusion is the main cause behind non-reduction of foreskin over the glans penis.

If paraphimosis is not treated early then it might compromise the blood flow to the glans leading to constriction, which may lead to gangrene and finally amputation of the glans penis.

Paraphimosis is a relatively uncommon condition. Generally, paraphimosis is induced inadvertently, but there have been reported cases of coital induced and penile piercing that might lead to paraphimosis and ultimately necrosis of the glans penis. It is more prevalent in hospitals and nursing homes and occurs when a person or a parent retracts the foreskin and inadvertently leaves the foreskin retracted. Generally, the retracted foreskin comes back to its anatomical position; however, if there is some resistance in reduction of the foreskin, there is a greater chance of developing perpetual edema of the foreskin, thus predisposing to paraphimosis. Paraphimosis is more common in communities in uncircumcised or partially circumcised males.

In most instances, paraphimosis occurs after retracting the foreskin at the time of penile examination, cleaning of the glans penis, cystoscopy or urethral catheterization. It is of utmost importance for both the healthcare professionals as well as the patient to restore the retracted foreskin to its anatomical position to preclude paraphimosis.

Paraphimosis following urethral catheterization is a common process as prior to the insertion of a catheter, the doctor has to retract the foreskin to prepare and drape the glans penis. The retracted foreskin may be left in the retracted position inadvertently for hours to days. This might preclude the development of paraphimosis.

There are other less common causes of paraphimosis that can lead to this condition. These include Plasmodium falciparum infection, contact dermatitis (following the application of celandine juice to the foreskin), self-infliction (such as after piercing with a penile ring into the glans), erotic dancing or Haemophilus ducreyi (chancroid) infection.

The penile structure is divided into three main portions, which include root of the penis, body of the penis and glans penis that forms the distal end of the penis. The root of the penis is found under the pubic bone providing stability to the erect penis. The body of the penis forms the major portion of the penis and consists of cavernosal bodies including corpora cavernosa and corpus spongiosum. The cavernosal bodies are responsible for an erection when they are filled with blood. The glans forms the distal extension of corpus spongiosum, which is covered by a loose skin known as foreskin in uncircumcised men. Coronal sulcus forms a collar of tissue immediately behind the glans.

Penis is a very vascular structure, which is supplied by internal pudendal artery that arises from internal iliac artery branching into deep penile artery (supplying corpus cavernosum), urethral artery (supplying glans penis and corpus spongiosum) and bulbar artery (supplying bulbar urethra and bulbospongiosus muscle). It is also innervated by left and right dorsal nerves of pudendal nerve.

When the foreskin is retracted behind the glans for a prolonged period of time, it forms a tight band of tissue around the penis. Initially, this tight band of tissue or constricting ring impairs the venous blood and lymphatic flow from the glans penis and foreskin, which ultimately leads to edema of glans penis. As there is worsening of the edema, the arterial blood flow is also compromised. This vascular obstruction along with tissue ischemia leads to painful swelling of the foreskin and glans penis, which eventually causes gangrene and autoamputation of the distal penis.