What is variant Creutzfeldt-Jakob disease?

Definition

Variant Creutzfeldt-Jakob disease (vCJD) is a type of prion
disease. Bovine spongiform encephalopathy is a
prion disease that affects cows, but there is evidence that this illness can be
transmitted to humans, producing vCJD. This illness is often called human mad-cow disease.

Causes

Prion diseases are a unique form of infectious diseases. The disease is not
produced by a bacterial or viral infection; instead, the illness is related to
progressive accumulation of prions (infectious protein particles).
The central nervous system is progressively damaged as these prions
accumulate.

Risk Factors

Exposure to prion-containing tissue is the primary risk factor. Other risk factors include eating beef from infected cows, receiving human growth hormone (HGH) injections before the mid-1980’s (changes in the preparation of HGH in the mid-1980’s eliminated this risk), working with brain tissue, and receiving a corneal or dura mater (brain lining) transplantation. Five to ten percent of all cases of the nonvariant form of Creutzfeldt-Jakob are inherited.

Symptoms

The average age of persons who get this disease is twenty-nine years. Rare
cases have been reported in children. Once a person is exposed, it can take up to
twenty years until symptoms develop. When symptoms develop they usually follow
three phases: early phase (zero to six months), in which psychiatric symptoms
predominate, including depression, anxiety, withdrawal, memory problems, and
difficulty pronouncing words; middle phase, in which neurologic symptoms
predominate, including abnormal gait, ataxia (problems with coordination),
involuntary movements (muscle jerks and stiffness), and cognitive decline
(impaired speech); late phase, in which symptoms include muteness (inability to
speak) and immobility. The average length of time from first symptoms to death is
thirteen months (with a range of six to thirty-nine months).

Screening and Diagnosis

A clinical history and physical exam are the primary diagnostic tools. If the
physician suspects vCJD,additional tests may be needed. These tests include a
lumbar puncture (a procedure to collect cerebrospinal fluid), a
magnetic
resonance imaging (MRI) scan (a scan that uses radio waves
and a powerful magnet to produce detailed computer images), a computed tomography (CT)
scan (a detailed X-ray picture that identifies abnormalities
of fine tissue structure), an electroencephalogram (EEG; a test used to evaluate
brain function or disorders), SPECT or PET scans (tests that produce images
showing the amount of functional activity in the tissue; used to differentiate
vCJD from other diseases), biopsy (removal of a sample of tonsil
tissue to test to confirm vCJD), and blood tests and cerebrospinal fluid analysis
(which may be used to distinguish this disease from other diseases, such as
Alzheimer’s). In many cases, final diagnosis requires autopsy and pathological
studies.

Treatment and Therapy

There is no cure for vCJD. Treatment is primarily supportive to maximize patient function and minimize patient discomfort.

Prevention and Outcomes

There have been more than two hundred cases of vCJD worldwide, most of which were associated with beef consumption in the United Kingdom. There is a great deal of controversy regarding safety of beef in the United States. Only a few cases of bovine spongiform encephalopathy have been detected in the United States, but no cases of vCJD have been attributed to eating beef originating in the United States. To minimize risk, it is generally recommended that people avoid eating beef products, particularly processed meat such as sausage and hotdogs, or beef items containing brain, spinal cord, or bone marrow.

Bibliography

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