Superficial siderosis of the central nervous system.

There have been 87 cases of superficial siderosis of the CNS reported in the world literature and 63 cases had developed the clinical syndrome with sufficient details to be reviewed. It is a distinct clinical syndrome characterized by sensorineural deafness (95%), cerebellar ataxia (88%) and pyramidal signs (76%). Other features include dementia (24%), bladder disturbance (24%), anosmia (at least 17%), aniscoria (at least 10%) and sensory signs (13%). Less frequent features are extra-ocular motor palsies, neck or backache, bilateral sciatica and lower motor neuron signs (5-10% each). Males are more often affected than females (3:1). The age of onset ranged from 14 to 77 years, age at death from 29 to 78 years and duration until death from 1 to 38 years excluding premature death due to the underlying cause or as a result of surgery. Up to 27% become bed bound at 1-37 years from the first symptom due to either cerebellar ataxia, a myelopathic syndrome or both. Symptomatic subarachnoid haemorrhage occurred in 37% and the CSF was haemorrhagic and/or xanthochromic in 75%. It is now accepted that superficial siderosis is due to chronic subarachnoid haemorrhage and a source of bleeding has been reported in 54% of cases; it was either due to dural pathology (47%) including a CSF cavity lesion or cervical root lesion, a vascular tumour (35%) or a vascular abnormality (18%). Arguments are presented that the remaining cases were also due to chronic haemorrhage and that there is no evidence for a non-haemorrhagic form of superficial siderosis. There have been 14 incidental cases diagnosed by MRI or at post-mortem with no symptoms attributable to superficial siderosis during life, supporting the notion of a pre-symptomatic phase to the illness. In 22 patients who had developed the syndrome, the duration of this pre-symptomatic phase could be calculated and ranged from 4 months to 30 years with an average of 15 years. At present the most promising treatment for superficial siderosis is surgical ablation of the bleeding sources.

Ageing and Parkinson's disease: substantia nigra regional selectivity.

The micro-architecture of the substantia nigra was studied in control cases of varying age and patients with parkinsonism. A single 7 mu section stained with haematoxylin and eosin was examined at a specific level within the caudal nigra using strict criteria. The pars compacta was divided into a ventral and a dorsal tier, and each tier was further subdivided into 3 regions. In 36 control cases there was a linear fallout of pigmented neurons with advancing age in the pars compacta of the caudal substantia nigra at a rate of 4.7% per decade. Regionally, the lateral ventral tier was relatively spared (2.1% loss per decade) compared with the medial ventral tier (5.4%) and the dorsal tier (6.9%). In 20 Parkinson's disease (PD) cases of varying disease duration there was an exponential loss of pigmented neurons with a 45% loss in the first decade. Regionally, the pattern was opposite to ageing. Loss was greatest in the lateral ventral tier (average loss 91%) followed by the medial ventral tier (71%) and the dorsal tier (56%). The presymptomatic phase of PD from the onset of neuronal loss was estimated to be about 5 yrs. This phase is represented by incidental Lewy body cases: individuals who die without clinical signs of PD or dementia, but who are found to have Lewy bodies at post-mortem. In 7 cases cell loss was confined to the lateral ventral tier (average loss 52%) congruent with the lateral ventral selectivity of symptomatic PD. It was calculated that at the onset of symptoms there was a 68% cell loss in the lateral ventral tier and a 48% loss in the caudal nigra as a whole. The regional selectivity of PD is relatively specific. In 15 cases of striatonigral degeneration the distribution of cell loss was similar, but the loss in the dorsal tier was greater than PD by 21%. In 14 cases of Steele-Richardson-Olszewski syndrome (SRO) there was no predilection for the lateral ventral tier, but a tendency to involve the medial nigra and spare the lateral. These findings suggest that age-related attrition of pigmented nigral cells is not an important factor in the pathogenesis of PD.

Diffuse Lewy body disease presenting with a supranuclear gaze palsy.

A patient with diffuse Lewy body disease presented with supranuclear vertical and horizontal ophthalmoplegia, dementia, axial rigidity and falls, bradykinesia and pyramidal signs. This broadens the clinical presentation of this pathological diagnosis and re-emphasises the heterogeneity of patients diagnosed clinically as progressive supranuclear palsy (Steele-Richardson-Olszewski syndrome).

Striatonigral degeneration. A clinicopathological study.

The clinical and pathological features of 10 cases of striatonigral degeneration are described: 5 were misdiagnosed in life as Parkinson's disease. Retrospectively, helpful early pointers to the diagnosis in these cases included unexplained falls, autonomic dysfunction, absence of rest tremor and failure to respond to L-dopa, but these were not always present. The pathological diagnosis could not be excluded on macroscopic examination of the striatum. Relative preservation of the putamen occurred in the 4 patients who benefited from L-dopa. The caudate nucleus was involved in all cases and there was no sparing of the large striatal neurons. In mild cases, involvement of the putamen was confined to its posterior two-thirds, dorsolaterally. With increasing severity this extended in a dorsal to ventral and posterior to anterior direction. Seven of the cases had evidence of olivopontocerebellar damage, but only 2 of these had clinical evidence of cerebellar disease. Correlation was found between the neuronal counts in caudate:putamen, striatum:nigra compacta, globus pallidus:nigra compacta, nigra compacta:locus coeruleus. The most severely involved part of the substantia nigra pars compacta was the ventrolateral zone, which projects to the dorsal putamen, the earliest site of striatal disease.