ABSTRACT
Regional cerebral blood flow (rCBF) during photic myoclonus was studied by means of positron emission tomography in a 51-year-old male patient suffering from MERRF (myoclonic epilepsy with ragged-red fibres). Frequencies of 3 Hz and 5 Hz flash stimulation were used. Both frequencies elicited paroxysmal EEG-abnormalities but only the higher frequency induced generalized myoclonic jerks. We found a left dominated significant increase of rCBF in the thalamus during myoclonus. The thalamic asymmetry was significant when tested with an ROI approach. The myoclonic activity was accompanied by significantly increased activity in the supplementary motor cortex (SMA). Decreases in rCBF were seen in the limbic, temporal and occipital areas during photic stimulation at both flash frequencies, more expressed during myoclonus. The findings observed in this patient indicate a thalamic focus for photic myoclonus in MERRF. We suggest that photic stimulation induced an abnormal discharge in the thalamus, which was fed forwards via thalamo-cortical connections to the precentral motor cortex, to produce the muscle jerks.
Subject(s)
MERRF Syndrome/physiopathology , Motor Cortex/pathology , Thalamus/pathology , Electroencephalography , Humans , Male , Middle Aged , Motor Cortex/blood supply , Motor Cortex/physiology , Photic Stimulation , Regional Blood Flow , Thalamus/blood supply , Thalamus/physiology , Tomography, Emission-ComputedABSTRACT
We have investigated nine maternal offsprings to patients with a hereditary syndrome of cerebellar ataxia, photomyoclonus, skeletal deformities and lipoma, originally described by Ekbom. The nine family members underwent a thorough neurological examination, neurophysiological investigations and molecular genetic analysis of mtDNA from lymphocytes and muscle. Clinical examination showed a partial syndrome in one relative and minor signs and symptoms in three additional offsprings. We found the heteroplasmic tRNALys A8344G point mutation in mtDNA in all investigated maternal offsprings. The fraction of mutated mtDNA ranged from 33 to 87% in lymphocytes and from 59 to 92% in muscle tissue. Analysis of mtDNA from a lipoma showed a high level (96%) of the tRNALys A8344G mutation. We conclude that Ekbom's syndrome is a mitochondrial encephalomyopathy associated with the same heteroplasmic tRNA mutation as seen in myoclonus epilepsy with ragged-red fiber (MERRF) syndrome.
Subject(s)
Cerebellar Ataxia/genetics , Cervical Vertebrae/pathology , DNA, Mitochondrial/genetics , Lipoma/genetics , Myoclonus/genetics , RNA, Transfer/genetics , Restless Legs Syndrome/genetics , Spinal Neoplasms/pathology , Adult , Child, Preschool , Electroencephalography , Electromyography , Humans , Lipoma/pathology , MERRF Syndrome , Male , Middle Aged , Pedigree , Point Mutation , Polymerase Chain Reaction , Restless Legs Syndrome/diagnosisABSTRACT
Seven consecutive patients with acute retropharyngeal tendinitis underwent plain X-ray and magnetic resonance imaging (MRI) of the cervical spine. All seven had marked soft tissue swelling anterior to C1 and C2 on plain X-ray, and soft tissue calcification at this level was present in five of them. On MRI, there was markedly increased signal intensity on T2-weighted images in the acute phase and intermediate signal intensity on T1-weighted images, anterior to the level of C1 and C2, often extending as far down as C6. These changes correlated well with the soft tissue swelling seen on conventional X-ray of the cervical spine. The maximum mid-sagittal thickness of the soft tissues was significantly greater in the tendinitis patients (p < 0.001) than in 12 control subjects free of symptoms from the pharynx or the cervical spine. Treatment with non-steroidal anti-inflammatory drugs rapidly alleviated symptoms, and at follow-up MRI showed regression or complete restitution of the changes. In conclusion, MRI can visualize the edematous changes in the longus colli muscle and adds useful diagnostic information in suspected cases of acute retropharyngeal tendinitis.
