Prion disease

The most common types of prion disease seen in humans are:

• Creutzfeldt-Jakob disease: Creutzfeldt-Jakob disease (CJD) is usually inherited from the family, which is why it is also known as familial CJD. Another type of CJD is sporadic CJD, which can develop suddenly without any known risk factor. Most cases of CJD are sporadic and are usually seen in people at or above the age of 60 years. The symptoms of CJD can quickly accelerate to severe disability and even death within a year.
• Variant CJD: This is an infectious type of prion disease, which may be caused by eating infected meat. It is also believed that people who receive cornea transplants from infected donors or get operated on with contaminated medical equipment may get this disease. This type of CJD is usually seen in younger people.
• Kuru: Kuru is caused by eating human brain tissue which is contaminated with infectious prions. Due to increased awareness, this disease is very rare now. 
• Variably protease-sensitive prionopathy (VPSPr): VPSPr is similar to CJD and is seen in people around the age of 70 years. However, this disease is rare and is seen in people who have a family history of dementia.
• Gerstmann-Sträussler-Scheinker disease (GSS): GSS is also an extremely rare form of prion disease which causes loss of coordination and is usually seen around the age of 40 years.
• Fatal insomnia (FI): FI is a rare genetic neurodegenerative disorder in which the person is unable to sleep—the condition worsens with time.

The symptoms of prion diseases are as follows:

• Rapidly advancing dementia
• Difficulty in coordinating body movements such as walking 
• Visible changes in gait
• Hallucinations
• Stiffness in the muscles
• Inability to speak
• Persistent fatigue
• Confusion

Prion protein is normally found on the surface of many cells. When it starts becoming abnormal and forms clumps in the brain, it results in brain damage, which can progress rapidly and ultimately result in death.

The exact reason for this change in the prion protein is not known yet.

People who have a family history of prion disease or consume cow meat are at risk of developing prion diseases. People who need corneal transplant surgery may suffer from prion disease if they receive a contaminated cornea.

People with a history or family history of prion disease must not donate organs or tissues. Doctors and health professionals must clean and sterilize their medical equipment thoroughly to prevent the spread of the disease.

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The diagnosis of prion diseases is very difficult as it can only be confirmed by doing a biopsy of brain tissue or after death. There are certain other tests that can be done by the doctors to diagnose prion diseases which may have symptoms similar to other diseases. The tests done to diagnose prion diseases include:

• MRI scans of the brain
• Cerebrospinal fluid examination by taking samples of fluid from the spinal cord by doing a lumbar puncture
• Electroencephalogram (EEG) is a painless test, which is done placing electrodes on the scalp to determine the brain waves. 
• Complete blood count
• Visual examination and neurological examination to determine any loss of vision or nerve function
• Genetic tests would be performed to check if the condition is hereditary.

There is no cure for prion diseases. The doctors may provide some medications to slow down the progression of the disease. Supportive care is provided to the patients to make their lives comfortable.