Retinal vein occlusion is a blockage in the blood supply from the retina -- the light-sensitive tissue in the back of the eye.

Central retinal vein occlusion; Branch retinal vein occlusion; CRVO; BRVO

Veins of the retina can become blocked by a blood clot. Retinal vein occlusion also can occur when the retinal arteries put pressure on the retinal vein. This is usually caused by a condition such as:

• Blood clot
• Diabetes
• Glaucoma
• Hardening of the arteries (atherosclerosis)
• High blood pressure

Retinal vein occlusion most often affects older people. Risk factors are related to the disorders that cause the blockage.

• Sudden blurring or vision loss in all or part of one eye

Tests to evaluate the retina include:

• Color vision
• Examination of the retina after dilating the pupil
• Fluorescein angiography
• Intraocular pressure
• Pupil reflex response
• Refraction test
• Retinal photography
• Slit lamp examination
• Testing of side vision (visual field examination)
• Visual acuity

Other tests may include:

• Blood tests for diabetes, high cholesterol, and triglyceride levels
• Blood tests to look for a clotting problem (in patients under age 40)

The health care provider should closely monitor any blockage for several months, because many harmful effects, such as glaucoma, take 3 or more months to develop.

Treatment can include aspirin and laser therapy.

Clinical trials are now underway to determine whether drugs that stop the growth of abnormal blood vessels (anti-VEGF drugs) might help treat retinal vein occlusion.

The outcome varies. Patients with retinal vein occlusions often regain excellent sight.

• Glaucoma
• Partial or complete vision loss in the affected eye

Call your health care provider if you have sudden blurring or vision loss.

The measures used to prevent other blood vessel diseases, such as coronary artery disease, may decrease the risk of retinal vein occlusion. These measures include:

• Eating a low-fat diet
• Exercising
• Losing weight if you're overweight

Aspirin is commonly used to prevent additional blockages in the vein.

Controlling diabetes is also helpful for preventing retinal vein occlusion.

Wu L, Arevalo JF, Roca JA, Maia M, Berrocal MH, Rodriguez FJ, et al. Pan-American Collaborative Retina Study Group (PACORES). Comparison of two doses of intravitreal bevacizumab (Avastin) for treatment of macular edema secondary to branch retinal vein occlusion: results from the Pan-American Collaborative Retina Study Group at 6 months of follow-up. Retina. 2008;28:212-219.

Kreutzer TC, Alge CS, Wolf AH, Kook D, Burger J, Strauss R, et al. Intravitreal bevacizumab for the treatment of macular oedema secondary to branch retinal vein occlusion. Br J Ophthalmol. 2008;92:351-355.

Renal cell carcinoma is a type of kidney cancer in which the cancerous cells are found in the lining of very small tubes (tubules) in the kidney.

Renal cancer; Kidney cancer; Hypernephroma; Adenocarcinoma of renal cells; Cancer - kidney

Renal cell carcinoma is the most common type of kidney cancer in adults. It occurs most often in men ages 50 - 70.

The exact cause is unknown.

Risk factors include:

• Dialysistreatment
• Family history of the disease
• Genetics
• High blood pressure
• Horseshoe kidney
• Smoking
• Von Hippel-Lindau disease (a hereditary disease that affects the capillaries of the brain, eyes, and other body parts)

• Abdominal pain
• Back pain
• Blood in the urine
• Enlargement of the veins around a testicle (varicocele)
• Flank pain
• Swelling or enlargement of the abdomen
• Unintentional weight loss

Other symptoms that can occur with this disease:

• Constipation
• Cold intolerance
• Excessive hair growth in females
• Pallor
• Vision abnormalities

Sometimes both kidneys are involved. The cancer spreads easily, most often to the lungs and other organs. In about one-third of patients, the cancer has already spread (metastasized) at the time of diagnosis.

Examination of the abdomen may show a mass or organ enlargement, particularly of the kidney or liver. Men may have a varicocele in the scrotum (a varicocele that is only on the right side is especially suspicious).

Tests include:

• Abdominal CT scan
• Blood chemistry
• Complete blood count (CBC)
• Intravenous pyelogram (IVP)
• Liver function tests
• Renal arteriography
• Ultrasound of the abdomen and kidney
• Urinalysis and urine cytology

The following tests may be performed to see if the cancer has spread:

• Abdominal CT scan
• Abdominal MRI
• Bone scan
• Chest x-ray
• PET scan

Surgical removal of all or part of the kidney (nephrectomy) is recommended. This may include removing the bladder or surrounding tissues or lymph nodes.

In some patients, surgery to remove a small number of tumors that have spread (metastases) may be helpful.

Radiation therapy usually does not work for renal cell carcinoma so it is not often used. Hormone treatments may reduce the growth of the tumor in some cases.

Chemotherapy is generally not effective for treating renal cell carcinoma. The drug interleukin-2 (IL-2), which works by helping the body's own immune system kill the cancer cells, may help a small number of patients, but it is very toxic. Other chemotherapy drugs have been used, but patients generally do not live long once the disease has spread outside the kidney.

Newer therapies include sorafenib (Nexavar), sunitinib (Sutent), and temsirolimus (Torisel). The biologic drug bevacizumab (Avastin) has also been used.

A cure is unlikely unless all of the cancer is removed with surgery.

You can ease the stress of illness by joining a support group whose members share common experiences and problems.

See also:

• Cancer - support group
• Kidney disease - support group

The outcome depends on how much the cancer has spread and how well it responds to treatment. The survival rate is highest if the tumor is in the early stages and has not spread outside the kidney. If it has spread to the lymph nodes or to other organs, the survival rate is much lower.

• High blood pressure (hypertension)
• High calcium level
• High red blood cell count
• Liver function abnormalities
• Spread of the cancer

Call your health care provider any time you see blood in the urine. Also call if you have any other symptoms of this disorder.

Stop smoking. Follow your health care provider's recommendations in the treatment of kidney disorders, especially those that may require dialysis.

Barjorin D. Tumors of the kidney, bladder, ureters, and renal pelvis. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 2007.

National Comprehensive Cancer Network Clinical Practice Guidelines in Oncology: Kidney Cancer. V.1.2009. National Comprehensive Cancer Network; 2009.