Transmissible Spongiform Encephalopathy

Alternative names
Creutzfeldt-Jakob disease; Mad Cow - new variant CJD

Definition
Creutzfeldt-Jakob disease is a disorder involving rapid decrease of mental function and movement. These are abnormalities believed to be caused by damage done to the brain by a protein called a prion. This protein folds abnormally, and seems to encourage other proteins to become similarly misshapen, affecting their ability to function.

Causes, incidence, and risk factors

Creutzfeldt-Jakob disease can occur sporadically (for no known reason), as a result of exposure to contaminated products. Rarely, it can be genetically inherited. The disorder itself is rare, occurring in about 1 out of 1 million people. It usually first appears in midlife, beginning between ages 20 and 70, with average age at onset of symptoms in the late 50s.

However, some cases have occurred in adolescents who have received growth hormone derived from the pituitary glands of cadavers (dead bodies). Prions cannot be destroyed by ordinary disinfection techniques used to prevent transmission of viruses and bacteria. As a result, the hormone remains contaminated, and this exposure is believed to be responsible for the early onset of the disease in these people.

Cadaver-derived growth hormone has been replaced by synthetically manufactured growth hormone, so this source of contagion is no longer a problem. Other cases have occurred when people were given corneal transplants from infected donors, and from contaminated electrodes that were used in brain surgery (before it was known how to properly disinfect instruments).

More recently, a type of disease called new variant Creutzfeldt-Jakob disease has emerged. It was first reported in the U.K. in people who had eaten meat from cows who were fed infected bone meal.

The version of the disease found in cows has come to be known as “mad cow disease”, and nvCJD has been called “the human form of mad cow disease” in news accounts. This disease tends to affect younger people and has early psychiatric manifestations. There have not been any cases of nvCJD reported in the U.S.

Once symptoms appear, the disorder progresses rapidly and may be confused with other types of dementia - like Alzheimer’s disease. Both forms of CJD, however, are distinguished by extremely rapid progression from onset of symptoms to disability and death. There may be a familial tendency to acquire the disorder. Early symptoms include personality changes and difficulty with coordination.

Creutzfeldt-Jakob disease may be related to several other diseases also thought to be caused by prions, including kuru (seen in New Guinea women who ate the brains of deceased relatives as part of a funerary ritual), scrapie (found in sheep), bovine spongiform encephalitis - “mad cow disease,” and other rare human diseases, such as Gerstmann-Straussler-Scheinker disease and fatal familial insomnia.

Symptoms

     
  • Personality changes  
  • Hallucinations  
  • Muscle twitching  
  • Muscle stiffness  
  • Nervous, jumpy feelings  
  • Changes in gait (walking, locomotion)  
  • Lack of coordination - stumbling, falls  
  • Speech impairment  
  • Poor enunciation (hard-to-understand speech or mumbling)  
  • Sleepiness  
  • Delirium or dementia develops rapidly       o Deterioration in all aspects of brain function       o Profound confusion, disorientation

Additional symptoms that may be associated with this disease:

     
  • Memory loss  
  • Anxiety, stress, and tension

Signs and tests

The rapid onset and progression of symptoms is what distinguishes CJD from most other dementias. The disorder involves rapidly progressive dementia, myoclonus (rapid and brief muscle contraction or “jerk”), and rigidity of the body.

A neurological and motor system examination shows muscle twitching and spasm. There is a strong startle response. Muscle tone may be increased, or there may be weakness and muscle wasting (loss of muscle tissue). There may be abnormal reflexes or an increase in the response of normal reflexes.

Examination of visual fields show areas of blindness that the person may not realize are present. There is loss of coordination related to visual-spatial perception changes and changes in the cerebellum, the area of the brain that controls coordination (cerebellar ataxia).

An EEG (electroencephalograph, a reading of electrical activity of the brain) shows characteristic changes indicating Creutzfeldt-Jakob disease, if the symptoms have been present for at least 3 months.

Though not diagnostic, presence of the 14-3-3 protein in the spinal fluid (obtained by lumbar puncture, also called “spinal tap”) is highly suggestive of the disease, when accompanied by other characteristic symptoms.

Ultimately, the disease can only be confirmed by brain biopsy or by a post-mortem examination. This shows the characteristic spongiform (sponge-like) changes in the brain.

Treatment

There is no known cure for Creutzfeldt-Jakob disease. Custodial care may be required early in the course of the disease. Medications may be needed to control aggressive behaviors. These include sedatives, antipsychotics, and others.

The need to provide a safe environment, control aggressive or agitated behavior, and meet physiologic needs may require monitoring and assistance in the home or in an institutionalized setting. Family counseling may help in coping with the changes required for home care.

Visiting nurses or aides, volunteer services, homemakers, adult protective services, and other community resources may be helpful in caring for the person with Creutzfeldt-Jakob disease.

Behavior modification may be helpful, in some cases, for controlling unacceptable or dangerous behaviors. This consists of rewarding appropriate or positive behaviors and ignoring inappropriate behaviors (within the bounds of safety). Reality orientation, with repeated reinforcement of environmental and other cues, may help reduce disorientation.

Legal advice may be appropriate early in the course of the disorder, to form advance directives, power of attorney, and other legal actions that may make it easier to make ethical decisions regarding the care of an individual with Creutzfeldt-Jakob disease.

Expectations (prognosis)

The outcome is usually very poor. Complete dementia commonly occurs within 6 months or less of the onset of symptoms, with the person becoming totally incapable of self-care.

The disorder is fatal in a short time, usually within 7 months, but a few people survive as long as 1 or 2 years after diagnosis of the disorder. The cause of death is usually infection, heart failure, or respiratory failure.

Complications

     
  • Infection  
  • Heart failure  
  • Respiratory failure  
  • Loss of ability to function or care for oneself  
  • Loss of ability to interact with others  
  • Side effects of medications used to treat the disorder (see the specific medication)  
  • Death

Calling your health care provider

Creutzfeldt-Jakob disease is not a medical emergency, but early diagnosis and treatment may make the symptoms easier to control, allow patients time to make advance directives, and give families additional time to come to terms with the condition.

Prevention

Risk of transfer of the organism on equipment or tissue is minimized by the health care provider. Treatment equipment is sterilized to kill organisms that may cause the disease. Medical histories of potential cornea donors that indicate a history of diagnosed or possible Creutzfeldt-Jakob disease rule out the use of those corneas for transplantation.

Most countries now have strict guidelines for management of infected cows and strict restrictions regarding what they are fed, to avoid the potential for transmission of CJD to humans.

Johns Hopkins patient information

Last revised: December 5, 2012
by David A. Scott, M.D.

Medical Encyclopedia

  A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | 0-9

All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.