Albert N. Martins

Resistance to drainage of cerebrospinal fluid: clinical measurement and significance

By infusing saline intrathecally at a constant rate until a new steady-state cerebrospinal fluid (CSF) pressure is attained, one can estimate clinically the apparent resistance (Ra) to drainage of CSF in mm saline/ml./minute. This intrathecal saline infusion test (ITSIT) was performed 36 times on 29 patients with diverse intracranial problems, and the results were analysed and, in most cases, compared with the pneumoencephalogram and the isotope cisternogram. The ITSIT is a safe, simple test to estimate Ra, but factors which are difficult to control (occult leaks from the subarachnoid space; independent fluctuations of CSF pressure) limit its reliability and clinical usefulness. If closely correlated with the clinical syndrome, the pneumoencephalogram, and the isotope cisternogram, an ITSIT may identify decisively the patient who needs a shunt. In addition the ITSIT offers another method by which to investigate the pathophysiological mechanisms of the various states of intracranial hypertension. Results from the test performed on four patients with intracranial hypertension of unknown cause (pseudotumor cerebri) suggest that the underlying mechanism in this condition is probably an impediment to normal CSF drainage.

ACUTE HAEMORRHAGIC LEUCOENCEPHALITIS (HURST) WITH A CONCURRENT PRIMARY HERPES SIMPLEX INFECTION.

In 1941 Hurst described a rapidly progressive acute disease of the central nervous system which he named acute haemorrhagic leucoencephalitis. It is a rare disorder; less than 40 cases have been reported, and its aetiology is still unknown. Before 1963, the reported cases of acute haemorrhagic leucoencephalitis had been diagnosed after death. We have had the opportunity, however, to treat a patient who developed the disease and recovered. The diagnosis was established upon microscopic examination of an amputated temporal lobe. During the early stages of the illness his serum showed a significant rise of the complement-fixing antibody titre to herpes simplex. We have a two-fold purpose in presenting this case report. First, the opportunity for follow-up evaluation of patients with proven acute haemorrhagic leucoencephalitis is rarely encountered; consequently, we are prompted to make the data which we collected generally available. Secondly, we wish to consider the significance of the unprecedented association which was established between acute haemorrhagic leucoencephalitis and a primary herpes simplex infection.