May 2003
Creutzfeldt-Jakob Disease (CJD) is a rare disease that affects the central nervous system. There are two forms of CJD, classical and a new form, variant. Three types of classical CJD are recognized: sporadic, familial and iatrogenic.
Classical CJD occurs in the general population at a rate of about one case per million people per year throughout the world. In Canada, about 30 cases of classical CJD are diagnosed each year.
The average age of onset of classical CJD is 60 years of age, with most cases in patients between 45 and 75. Death often occurs within 2 to 3 months, with 70 percent of patients dying in less than 6 months.
In classical CJD, the period between exposure to the infection in cases where this is known and the onset of symptoms can range from 1 to 30 years or more. Symptoms usually occur suddenly and the patient's condition rapidly declines. Early symptoms include lapses in memory, mood swings similar to depression, lack of interest and social withdrawal. The patient may become unsteady on his/her feet. Later symptoms may include blurred vision, sudden jerking movements and rigidity in the limbs. The patient may experience slurred speech and have difficult swallowing. There is progressive mental deterioration and, eventually, movement and speech are lost.
Currently, the only way to diagnose classical CJD with certainty is by microscopic examination of the brain tissue, most often through autopsy.