A varicocele is an enlargement of the veins within the loose bag of skin that holds the testicles (scrotum). A varicocele is similar to a varicose vein that can occur in the leg.
Varicoceles are a common cause of low sperm production and decreased sperm quality, which can cause infertility. However, not all varicoceles affect sperm production. Varicoceles can also cause testicles to fail to develop normally or shrink.
Most varicoceles develop over time. Fortunately, most varicoceles are easy to diagnose and many don't need treatment. If a varicocele causes symptoms, it often can be repaired surgically.

Symptoms :

A varicocele often produces no signs or symptoms. It may be discovered during a fertility evaluation or a routine physical exam. Rarely, it may cause pain. 
Symptoms are: 
  • Pain and swelling in the scrotum
  • Mass may be noticed in the scrotum
  • problems with fertility
The pain may:
  • Vary from sharp to dull discomfort
  • Increase with standing or physical exertion, especially over long periods
  • Worsen over the course of a day
  • Be relieved when you lie on your back
With time, varicoceles may enlarge and become more noticeable. In young men, the presence of a varicocele impairs sperm production and can often be improved with treatment.

Causes :

The cause of varicocele is not known. The spermatic cord carries blood to and from the testicles. It is believed that a varicocele forms when the valves inside the veins in the cord prevent the blood from flowing properly. The resulting backup causes the veins to widen (dilate). This may then result in damage to the testicle and result in worsened fertility.
Varicoceles often form during puberty. They usually occur on the left side. However, a varicocele in one testicle can affect sperm production in both testicles.

Complications :

A varicocele may cause
  • Shrinkage of the affected testicle (atrophy). The malfunctioning valves of the testicular veins allow blood to pool in the veins, which can result in increased pressure in the veins and exposure to toxins in the blood that may cause testicular damage.
  • Infertility. Varicoceles may keep the local temperature in or around the testicle too high, affecting sperm formation, movement (motility) and function.

Tests and diagnosis :

The  doctor will conduct a physical exam, which may reveal a nontender mass above the testicle that feels like a bag of worms. The doctor may ask the patient to stand, take a deep breath and hold it while the patient bears down. This helps the doctor detect abnormal enlargement of the veins.
A scrotal ultrasound is another test that may be used to ensure there isn't another reason for the symptoms.
In certain cases, further imaging may be recommended to rule out other causes for the varicocele, such as a tumor compressing the spermatic vein.

Treatments and drugs :

Varicocele treatment may not be necessary. However, if the varicocele causes pain, testicular atrophy or infertility or if person is considering assisted reproductive techniques, he may want to undergo varicocele repair.
The purpose of surgery is to seal off the affected vein to redirect the blood flow into normal veins. Clear indications to repair a varicocele in adolescence include progressive testicular atrophy, pain or abnormal semen analysis results. The treatment of a varicocele may generally improve sperm characteristics.
Varicocele repair presents relatively few risks, which may include:
  • Buildup of fluid around the testicles (hydrocele)
  • Recurrence of varicoceles
  • Testicular atrophy
  • Infection
  • Damage to an artery
Repair methods include:
Open surgery. This is usually is done on an outpatient basis, with a general or local anesthetic. Commonly, the surgeon will approach the vein through the groin (inguinal or subinguinal), but it's also possible to make an incision in the abdomen or below the groin.
One may be able to return to normal, nonstrenuous activities after two days of the surgery. It is possible to return to more strenuous activity, such as exercising, after two weeks.
Pain from this surgery generally is mild. The doctor may prescribe pain medication for a limited period after surgery. The doctor may advise not to have sex for a period of time. Most often, it will take several months after surgery before improvements in sperm quality can be seen with a semen analysis. This is because it takes approximately three months for new sperm to develop.
Laparoscopic surgery. The surgeon makes a small incision in the abdomen and passes a tiny instrument through the incision to see and to repair the varicocele. This procedure requires general anesthesia.