Creutzfeldt-Jakob Disease Health Article

Definition

Creutzfeldt-Jakob disease (CJD) is a transmissible, rapidly progressing, fatal neurodegenerative disorder related to "mad cow disease."

Description

Before 1995, Creutzfeldt-Jakob disease was little known outside the medical profession. Indeed, most physicians did not know much about the disease, and few had ever seen a patient with the disease. But with the discovery of a "new variant" form, the possibility that those with the disease became infected simply by eating beef, and the radical theory that the infectious agent is a rogue protein, CJD has become one of the most talked about diseases in the world, and has taken on a significance far beyond the small number of deaths it currently causes each year.

First described in the 1920s, CJD is a neurodegenerative disease causing a rapidly progressing dementia which ends in death, usually within eight months of the onset of symptoms. It is also a very rare disease, affecting only about one in every million people in the population worldwide. In the United States, CJD is thought to affect about 250 people each year. CJD affects adults of all ages, but is rare in young adults and most common between ages 50 and 75.

Spongiform encephalopathies

The most obvious pathologic feature of CJD is the formation of numerous, fluid-filled spaces in the brain (vacuoles), giving the brain a sponge-like appearance. CJD is one of several human spongiform encephalopathies, diseases that produce this characteristic change in brain tissue. Others include kuru; Gerstmann-Straussler-Scheinker dis- ease, predominantly characterized by cerebellar ataxia; and fatal familial insomnia, associated with progressive insomnia, autonomic system dysfunction, and weakness caused by motor system dysfunction.

Kuru was prevalent among the Fore people in Papua New Guinea,. The disease was spread from infected individuals after their deaths through the practice of ritual cannibalism, in which the relatives of the dead person honored him by consuming his organs, including the brain. Discovery of the infectious nature of kuru won the Nobel Prize for Carleton Gadjusek in 1976 and also alerted the medical world to the possibility of slow-acting infectious agents, collectively termed slow-virus diseases. The incubation period for kuru was four to 30 years or more. While kuru has virtually disappeared following the cessation of cannibalistic practices, several new cases continue to arise each year.

Cases of CJD have been grouped into three types: familial, iatrogenic, and sporadic.

• Familial CJD, representing 5–15% of cases, is inherited in an autosomal dominant manner, meaning that either parent may pass along the disease to a child, who may then develop CJD later in life.
• Iatrogenic CJD occurs when a person is infected during a medical procedure, such as organ donation and transplantation, blood transfusion, or brain surgery. The rise in organ donation has increased this route of transmission. Grafts of infected corneas and dura mater (the tissue covering the brain) have been linked with the transmission of CJD. Another source is hormones concentrated from the pituitary glands of cadavers, some of whom carried CJD, for use in people with growth hormone deficiencies. Iatrogenic infection represents a small fraction of all cases. The incubation period between exposure to the infectious agent is very long and is estimated to be from less than 10 to more than 30 years.
• Sporadic CJD represents at least 85% of all cases. Sporadic cases have no identifiable source of infection. Death usually follows the appearance of the first symptoms within eight months.