Hereditary spastic paraplegia with corpus callosum and thoracic spinal cord atrophy

Introduction: Hereditary spastic paraplegia is clinically characterized by slowly progressing gait disorder due to a bilateral spasticity and weakness of lower limbs. It is classified into a pure and a complicated form. The latter also shows accompanying symptoms and clinical findings, such as dementia, ataxia, extrapyramidal signs, epileptic seizures, optic neuritis or retinopathy. Depending on the age at the time of clinical manifestation, spastic paraplegia is also divided into early- and late onset variants. Pathologic changes in hereditary spastic paraplegia are mostly limited to the spinal cord with degeneration of the distal ends of corticospinal tracts and dorsal columns. Involvement of the brain, such as corpus callosum atrophy or white matter lesions, has also been described. A broader use of magnetic resonance imaging has allowed the in vivo description of such lesions. Considering the involvement of the spinal cord several radiological studies have documented either normal spinal cord findings or a mild atrophy of the cervical and thoracic segments.

Case report: A 38-year old male was admitted to our department with progressing gait disturbance, which first manifested itself seven years ago. His two brothers and one uncle had also exhibited similar clinical features. On neurological evaluation the patient presented a severe spasticity and hyperreflexia of the lower limbs with extensor plantar responses and distal sensory deficits. On detailed neuropsychological examination no cognitive decline was revealed. After an extensive diagnostic work-up (MRI brain, CSF analysis, evoked potentials, EMG, serum vitamin B12 and E levels, serum arylsulphatase, galactocerebrosidase and VLCFA levels, HTLV-1 antibodies, HIV and syphilis serology) other disorders presenting with spastic paraparesis (e.g. abetalipoproteinemia, funicular myelosis, multiple sclerosis, AIDS, lues, adrenoleucodystrophy etc.) were excluded, allowing on the ground of the family history and the clinical features the diagnosis of pure hereditary spastic paraplegia. However, magnetic resonance imaging of the brain showed a marked atrophy of the splenium corporis callosi with hypertense T2-signal and no contrast enhancement. Magnetic resonance imaging of the spinal cord demonstrated a significant atrophy of the thoracic spinal cord. The transverse diameters at the T3-, T6- and T9-levels were with 4.0 mm markedly (50-60%) reduced compared to published data from normal control subjects.

Conclusion: The present case report suggests that marked corpus callosum and spinal cord atrophy should not be considered as uncommon, however compatible with hereditary spastic paraplegia radiological findings. Magnetic resonance imaging can be a useful tool for the differential diagnostic work-up of cases with bilateral pyramidal paresis.

Key words: Hereditary spastic paraplegia, magnetic resonance imaging, spinal cord atrophy, corpus callosum atrophy.