A 49-Year-Old Man With Forgetfulness and Gait Impairment

Sumaira Nabi, MBBS, FCPS; Sadaf Fayyaz, MBBS; Shahzad Ahmed, MBBS


June 27, 2017


The patient in this case was diagnosed as having sporadic Creutzfeldt-Jakob disease (sCJD) on the basis of his clinical presentation and typical MRI brain findings. No history of human hormone supplement ingestion is noted. The facility for testing CSF for 14-3-3 protein is not available in Pakistan, where this patient presented. Brain biopsy is conclusive in such cases but was not performed, owing to an elevated risk for disease transmission and lack of family consent.

The patient was prescribed symptomatic medication for spasticity and myoclonic jerks and was sent home for rehabilitation. The prognosis and course of disease was explained to the family in detail.

CJD is a chronic progressive neurodegenerative disorder and is one of the human prion diseases.[1,2] It was first described by Creutzfeldt and Jakob in the early 1920s. It is a uniformly fatal disease, with an annual incidence rate of 1-2 cases per million population worldwide. CJD accounts for 85% of all human prion diseases.

The infectious agent in CJD is a prion that is composed mainly or entirely of an abnormal conformation of a host-encoded glycoprotein called the "prion protein." Its replication involves the recruitment of normally expressed prion protein, which mainly has an alpha-helical structure, into a disease-specific molecule that is rich in beta sheet.

CJD principally affects the gray matter of the cerebral cortex, the brainstem, and the molecular layer of the cerebellum.[3] Owing to abnormal prion protein accumulation in the brain, CJD is characterized by spongiform change, neuronal loss, and gliosis. In addition, amyloid protein is detected in cerebral cortex and cerebellum in 10% cases of CJD. These amyloid plaques are unlike Alzheimer disease, because CJD-related plaques are immunoreactive with antibodies directed against prion proteins.

Prion disease is transmitted via peripheral routes, either orally or transcutaneously. The prion then replicates in the spleen and peripheral lymph nodes. Only the variant form of CJD is transmissible via blood transfusion from human to human. After peripheral replication, hematogenous spread to the central nervous system occurs and depends on the presence of B lymphocytes. Prions can also reach the central nervous system via vagus parasympathetic nerves.[4,5,6] Familial CJD is rare and is inherited as a mutation in the human prion protein gene (PRNP) on chromosome 20.

There are four types of CJD. The most common form is sCJD, which accounts for 85%-90% of the total cases; the others are familial, iatrogenic, and variant forms.[7,8] The mean age of onset in sCJD is 65 years, and most cases occur between age 60 and 80 years.[9] Cases of sCJD in patients younger than 30 years or older than 80 years are rare.[7,8] The etiology of CJD is still unknown, and both genders are almost equally affected.

Its clinical features mainly include a rapidly progressive dementia; psychiatric symptoms; and multifocal neurologic findings, such as myoclonus, visual disturbances, and cerebellar and pyramidal/extrapyramidal signs. The disease follows a rapid course, with progression of cognitive and functional impairment toward akinetic mutism in the late stage. Eventually, death occurs, most often within 12 months of the disease onset.[9,10,11]

Myoclonus in CJD, especially provoked by startle, is present in more than 90% of patients at some point during their illness; however, it may be absent at presentation, even when dementia is very profound. sCJD should always be considered in the patients who have rapidly progressive dementia with myoclonus.


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