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BMJ No 7131 Volume 316 Papers Saturday 21 February 1998
Single photon emission computed tomography in the identification of new variant Creutzfeldt-Jakob disease: case reportsRajith de Silva, James Patterson, Donald Hadley, Aline Russell, Martin Turner, Martin Zeidler See Editorial by Pocchiari, p 563 and Paper (full text), p 577 New variant Creutzfeldt-Jakob disease may be associated with exposure to the causative agent of bovine spongiform encephalopathy.(1) Currently, a reliable diagnosis is possible only after neuropathological examination of the brain, which is risky for patients and diagnosticians.(2) The sensitivity and specificity of recently developed techniques are not known for new variant Creutzfeldt-Jakob disease, and they are available only in highly specialised centres.(3,4) Single photon emission computed tomography is a readily available neuroimaging technique that uses intravenously administered radioactive ligands to map different aspects of brain function. We report the findings on this technique using the cerebral perfusion tracer hexamethylpropyleneamineoxime (HMPAO) in two patients with neuropathologically confirmed new variant Creutzfeldt-Jakob disease. Patients, methods, and resultsCase 1 - A 28 year old woman developed paraesthesia of her right arm, then right leg, and later both left arm and leg. Six months later she complained of weight loss and fatigue, and had mild ataxia. After 1 year, speech, memory, and behavioural abnormalities were identified, her ataxia had worsened, and choreiform movements were noted. Six months later she developed myoclonus, primitive responses, pyramidal signs, and severe limb and truncal ataxia. Finally, she became rigid and mute; she died 23 months after the onset of her symptoms. An electroencephalogram taken 11 months after initial presentation showed no abnormalities. A repeat tracing 3 months later showed no abnormalities either, and at that time, results from magnetic resonance imaging of the brain were reported as normal apart from showing mild atrophy. Simultaneous single photon emission computed tomography showed hypoperfusion, most marked in the left temporoparietal region. The diagnosis of new variant Creutzfeldt-Jakob disease was established histopathologically.
Finally, she had rest and stimulus sensitive myoclonus, and was mute. She died 14 months after the onset of her illness. The histopathological findings were characteristic of new variant Creutzfeldt-Jakob disease. Serial electroencephalographic recordings (the last was performed 10 days before her death) showed progressive slowing of background rhythms but no typical periodic complexes.
CommentThe two patients presented consecutively at this institute, and necropsy confirmed that they had died of new variant Creutzfeldt-Jakob disease. As with other cases of the disease identified to date, early diagnosis was hampered by the absence or subtlety of neurological features, and by comparatively normal results in investigations. The clinically important abnormalities of cerebral perfusion on single photon emission computed tomography, when findings on electroencephalography or cerebral magnetic resonance imaging were normal, raised or supported the diagnosis of an organic encephalopathy in both cases. Similar abnormalities shown in single photon emission computed tomography have been reported in sporadic Creutzfeldt-Jakob disease, and a patient who died 7 weeks after onset had a unilateral perfusion deficit corresponding to the clinical, electroencephalographic, and pathological abnormality.(5) Although the perfusion abnormalities seen here are non-specific and cannot be claimed to be diagnostic of new variant Creutzfeldt-Jakob disease, they are more marked and widespread than those associated with depression. Consequently, the technique may prove useful in raising the possibility of the disease in young patients presenting with unusual psychiatric or neurological syndromes, with normal or unhelpful results in routine investigations.
We thank Professor Ian Bone and Dr William Durward for giving
their permission to publish these cases. The histopathological
examinations were performed at the National CJD Surveillance Unit by Dr
James Ironside.
Contributors: RdeS, JP, and DH raised the possibility of using
single photon emission computed tomography as a diagnostic
"pointer" in new variant Creutzfeldt-Jakob disease, and RdeS wrote
the paper. AR, MT, and MZ discussed the core concept and suggested
amendments to the early drafts. JP and DH reviewed the final
manuscript. MT contributed psychiatric data in case 2, and AR
interpreted the electrophysiological data. JP and DH interpreted the
single photon emission computed tomograms. DH interpreted the other
radiological studies and collated these with the single photon emission
computed tomography scans. MZ was involved in establishing the final
diagnoses.
Funding: None.
Conflicts of interest: None.
(Accepted 21 July 1997)
Department of Neurology, Rajith de Silva, senior registrar Department of Neuroradiology, Department of Electrophysiology, Woodilee Psychiatric Hospital, National CJD Surveillance Unit, Correspondence to: Dr de Silva References
1 Will R G, Ironside J W, Zeidler M, Cousens S N, Estibeiro K,
Alperovitch A, et al. A new variant of Creutzfeldt-Jakob disease in the
UK. Lancet 1996;347:921-5.
2 Will R G, Zeidler M. Diagnosing Creutzfeldt-Jakob disease.
BMJ 1996;313:833-4.
3 Will R G, Zeidler M, Brown P, Harrington M, Lee K H, Kenney K L.
Cerebrospinal-fluid test for new-variant Creutzfeldt-Jakob disease.
Lancet 1996;348:955.
4 Hill A F, Zeidler M, Ironside J, Collinge J. Diagnosis of new
variant Creutzfeldt-Jakob disease by tonsil biopsy. Lancet
1997;349:99-100.
5 Kirk A, Ang L C. Unilateral Creutzfeldt-Jakob disease
presenting as rapidly progressive aphasia. Can J Neur Sci
1994;21:350-2.
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