Granulomatous angiitis of the central nervous system: a case with recurrent intracerebral haemorrhage.

A 43-year-old man with a history of radiculomyelopathy developed recurrent intracerebral haemorrhage confirmed by CT brain scan. Cerebral angiography and systemic investigations showed no underlying cause for the haemorrhage. Cerebral biopsy at the time of evacuation of a haematoma revealed granulomatous angiitis. This condition may be responsive to steroids and should be considered in cases of intracerebral haemorrhage of obscure origin.

Chronic optic nerve compression. An experimental study.

Chronic progressive compression of the optic nerve in the cat was produced by an inflatable silicon rubber balloon implanted in the orbit. Within the first week the predominant pathological change was demyelination. Both partially and completely demyelinated fibres were seen at all stages of the experiments but by the fifth week some axons had been remyelinated by oligodendrocytes despite the continued presence of the balloon. The myelin sheaths of the new internodes were abnormally thin and short, and many showed an atypical paranodal organization. There was evidence of breakdown of some of the new internodes. The pathophysiology of optic nerve compression in man is reviewed.

Cavernous sinus thrombosis.

Four patients with clinical and investigative features suggestive of cavernous sinus thrombosis are reported. Radiological investigations included computed tomography of head and orbits. The problem of clinical and radiological distinction from orbital infection is discussed. Serious intracranial complications developed in two patients and the value of computed tomography in detecting these is stressed.

Remyelination during optic nerve compression.

An inflatable silicone rubber balloon implanted in the orbit has been used to simulate an expanding orbital tumour. The changes produced in the compressed cat optic nerve have been investigated by light and electron microscopy. Within the first week extensive demyelination occurred; some fibres degenerated completely and there was marked proliferation of astrocytic processes. Some partially and completely demyelinated axons were seen throughout the period studied but after 5 weeks many axons had become remyelinated. Remyelinated fibres were seen in all longer-term animals despite the continued presence of the orbital mass. The significance of these observations is discussed in the light of the physiology of conduction in demyelinated and remyelinated central axons.

Remyelination during optic nerve compression.

The structural changes produced in cat optic nerve by incremental chronic compression have been investigated by light and electron microscopy. Within the first week extensive demyelination occurred; some fibres underwent Wallerian degeneration and there was marked proliferation of astrocytic processes. After 5 weeks of compression remyelinated fibres were seen and occurred in all longer-term animals despite the maintenance of compression, but some partially and completely demyelinated fibres persisted. Myelin thickness had not returned to normal in the remyelinated fibres after 19 weeks and was often strikingly variable. The significance of these observations is discussed in the light of the recent demonstration of the restoration of central conduction by remyelination.

Crossed acoustic response combined with visual and somatosensory evoked responses in the diagnosis of multiple sclerosis.

The crossed acoustic response, (CAR), a recently introduced test of brainstem function, has been studied in 66 patients with multiple sclerosis and 53 control subjects, and compared with conventional visual and somatosensory evoked responses (VER, SER). A latency abnormality was found in the CAR in 73% of patients, in the VER in 63%, and in the SER in 37%. Abnormalities have been related to the presence or absence of clinically detectable signs. All three responses detected subclinical lesions by showing abnormality in a proportion of multiple sclerosis patients who had no corresponding abnormal clinical signs (CAR 69%, VER 42%, SER 29%). The best diagnostic combination of responses was VER and CAR. Ninety per cent of patients had at least one of these two responses abnormal.