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| Discussion |
A 65-year-old man, farmer by occupation, presented with headaches,
tremulousness of body, unsteadiness of gait, giddiness, swaying to both
sides while standing and recurrent falls. There was also history of cognitive
deterioration in the form of memory disturbance, urgency and increased frequency
of micturition.
On clinical examination, the patient was conscious but not oriented in time,
place and person. Myoclonus was confirmed. Speech was low intensity, sometimes
incomprehensible. There was generalized increase in tone, cogwheel rigidity
of all four limbs, and bilateral cerebellar signs in the form of truncal
ataxia, dysdiadokokinesia, intention tremors and dysmetria.
RADIOLOGICAL Examination:
CT scan of the brain revealed bifrontal atrophy (Fig 1).
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Fig
.1
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MRI study of the brain revealed abnormal hyperintense signal on T2W and FLAIR images in caudate nuclei and putamen bilaterally with sparing of the globus pallidi. The lesion displayed restricted diffusion
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Fig.2
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Fig.
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Fig.
4
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DISCUSSION:
Creutzfeldt-Jakob disease,
also called Transmissible Spongiform Encephalopathy is a disorder characterised
by rapidly deteriorating mental function and abnormal movement. The etiologic
agent is a proteinaceous particle or prion, which causes neuronal damage.
Creutzfeldt-Jakob disease can occur sporadically - from exposure to contaminated
products such as growth hormone extracts from pituitary glands of cadavers
or rarely, it can be genetically inherited. The disorder is rare, occurring
in about 1 in a million people. The average age at onset of symptoms is
the late 50s - though it has been noticed from the second to the seventh
decades.
The patient may present with any of the following symptoms including personality
changes hallucinations, speech impairment with mumbling and poor enunciation,
muscle stiffness and twitching, gait disturbance and lack of coordination
causing stumbling and falls
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.
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. Early symptoms include personality
changes and difficulty with coordination.
DA neurological and
motor system examination shows muscle twitching and spasm, and 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 may reveal defects that the person may not
have noticed. There is loss of coordination related to visual-spatial perception
changes and changes in the cerebellum, accounting for the abnormalities
of coordination.
An electroencephalograph shows characteristic changes indicating Creutzfeldt-Jakob
disease in 75 to 90% of patients except in very early and terminal satges.Generalised
slow wave complex interrupted by periodic synchronous discharges are noted
if the symptoms have been present for at least 3 months.
MRI shows characteristic symmetrical hyperintense signals on T2W and FLAIR
images involving the basal ganglia (caudate nucleus, putamen with sparing
of the globus pallidus), thalamus and the cortex. Diffusion weighted images
are more sensitive than T2W and FLAIR images in detecting subtle early changes.
CT scan of the brain is of limited value as it only helps to exclude other
causes.
The presence of the 14-3-3 protein in the spinal fluid puncture is highly
suggestive of the disease especially when accompanied by other characteristic
symptoms. However it is not specific and may be seen in 50% of patients
with viral encephalitis, 4% of other dementia and in recent onset stroke.
Ultimately, the disease can only be confirmed by brain biopsy or by a post-mortem
examination. This shows the characteristic spongiform changes in the brain,
neuronal loss, amyloid plaques and reactive gliosis. No inflammatory reaction
is seen.
Prion protein single copy host gene (PRNP) is present on short arm of chromosome
20. Conformational change in the gene is believed to initiate the disease
process which causes accumulation of the abnormal protein.
Recently, a new variant of Creutzfeldt-Jakob disease or "mad cow disease"
has been reported in the U.K. in people who had eaten meat from cows fed
infected bone meal.This disease tends to affect younger people and has early
psychiatric manifestations.
Creutzfeldt-Jakob disease may be related to several other diseases also
thought to be caused by prions, including kuru, scrapie, bovine spongiform
encephalitis -- "mad cow disease," and other rare human diseases, such as
Gerstmann-Straussler-Scheinker disease and fatal familial insomnia.
There is no known cure for Creutzfeldt-Jakob disease, hence prevention of
transmission is essential. Custodial care and medications may be needed
to control aggressive behaviors.
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 6 to 8 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, cardiac failure, or respiratory
failure.
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.