John D. Ward

AN EVIDENCE-BASED APPROACH TO MANAGEMENT OF INCREASED INTRACRANIAL PRESSURE

Current treatment of many conditions associated with elevated ICP of the brain involves stabilization and oxygenation with maintenance of adequate perfusion of cerebral tissue, while maintaining an acceptable ICP. As an example of a standard protocol that is in concordance with what is already known about a patient with a severe head injury, the first priority is radiographic screening for a surgical lesion. Further treatment, as shown by the previously outlined studies, includes keeping the patient normothermic, normoglycemic, and normocapnic, and placing an indwelling ICP monitor. Acutely elevated ICP is treated with mannitol, and if this fails, patients are routinely sedated, paralyzed, and mildly hyperventilated, while repeat radiology is obtained to rule out a further surgical lesion. Hypothermia, aggressive hyperventilation, and barbiturate coma continue to be used and are reserved for intractable ICP elevation, or as warranted based on a specific patient (Table 2).

Endothelial fenestrations and other vascular alterations in primary melanoma of the central nervous system.

A primary malignant melanoma of the central nervous system is studied by light and electron microscopy. There were numerous endothelial fenestrae and basement membrane abnormalities in intrinsic tumor capillaries. It is felt that these vascular abnormalities may play a role in explaining why these tumors have an increased incidence of bleeding. No characteristic findings were encountered which would help distinguish this tumor from one of peripheral origin.

Methylprednisolone treatment in patients with brain tumors.

A study was made in 10 patients with brain tumors of the effect of methylprednisolone sodium succinate (Solu-Medrol) on clinical neurological status, intracranial pressure, and periventricular elastance. Significant clinical improvement and reduction in periventricular elastance both ocurred within 24 hours of starting treatment, whereas intracranaial pressure was not significantly reduced until the 2nd day of therapy.

Traumatic Brain Tissue Acidosis: Experimental and Clinical Studies

We have been focusing on potential metabolic derangement associated with severe head injury and a clinical trail directed toward treating brain tissue acidosis is currently underway. More specifically, we based this study on the hypothesis that following brain trauma brain tissue acidosis develops which may contribute to the prolongation of coma and neurologic deficit. Tromethamine (THAM), a safe and low toxicity agent which buffers in major part by causing a hypocapnic alkalosis, was selected for trial. Patients admitted with GCS < 8 were randomized into one of three arms: control: THAM plus hyperventilation; hyperventilation alone. Each regimen was maintained for 5 days post injury. Our analysis of 3 and 6 months Glasgow outcome score showed that prophylactic hyperventilation retards recovery, and the use of THAM overcomes the apparent deleterious effects of hyperventilation. One explanation is that the reduced ICP instability observed in THAM treated patients may account for this improvement. Is THAM effective in buffering traumatized brain tissue? What factors account for improvement in ICP stability? We addressed these questions in experimental studies utilizing MR spectroscopy to measure brain lactate production and tissue pH in fluid percussed anaesthetized cats. The protocol was designed to match our clinical trial, and brain injured animals were randomized into control, THAM, and hyperventilated groups. We observed that brain lactate production increased with trauma and remained above control at 8 hrs post injury. Lactate production in THAM treated animals was not elevated. Highest lactate production was associated with injured animals treated with sustained hyperventilation.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain tissue pH in severely head-injured patients: a report of three cases

It is well established that low cerebrospinal fluid (CSF) pH and high CSF lactate concentration indicate the development of brain acidosis after severe human head injury. However, there is no direct evidence that tissue acidosis actually occurs. We measured brain extracellular pH (pHe) in three patients undergoing operation for the evacuation of acute subdural hematomas. A pH-sensitive polymer membrane electrode was inserted 500 micron into the cerebral cortex close to the damaged area. The pHe values obtained were correlated with ventricular CSF acid-based parameters and extension of the brain lesion. The CSF pH was higher than the pHe in all cases; the pHe was particularly low in areas of contusion or compression by mass lesion. The effect of focal brain tissue acidosis on clinical course after severe head injury is discussed.

Spectral Analysis of the EEG in Craniocerebral Trauma

The objectives of the present study were to evaluate the relationship between the fractional amplitudes of the EEG derived from power spectral analysis (PSA) of the electroencephalogram (EEG) and depth of coma measured clinically with the Glasgow Coma Score, and to assess the accuracy of PSA in predicting long-term outcome. Thirty-two patients rendered unconscious by blunt head injury (mean (GCS = 7) had intermittent EEG recordings daily from 1-10 days post injury. There was a significant correlation between fractional amplitude of the EEG and the GCS. The rate and magnitude of change in the EEG and GCS were also correlated. There were significant differences in PSA parameters between improved and deteriorated patient groups at the termination of monitoring (p = .02) and in the change of PSA parameters over time (p = .02). Using linear discriminant analysis of PSA parameters, the accuracy of outcome prognostication based on the six month outcome was approximately 75%. Accurate classification of outcome was possible in a number of patients in whom there was little or no change in the GCS during the period of monitoring.

Neurosurgical Applications of Clinical Olfactory Assessmenta

The neurosurgeon, through routine neurological examination, encounters olfactory deficits in those patients with skull fractures, contusions, lesions in the anterior fossa, and intracranial tumors. We randomly sampled 25 patients attending the head injury follow-up clinic and administered the CCCRC test of olfactory function’ including a butanol detection threshold and odor identification subtest. Patients were of ages 9 to 61 and most had sustained a severe head injury as evidenced by a score of eight or less on the Glasgow coma scale. All patients were tested at least two months postinjury and were judged competent and coherent on the basis of an independent neuropsychological interview and assessment. FIGURE 1 compares olfactory function in severe head injury patients to a group of 65 normal subjects.* Almost 60% of the head injury patients were found to be anosmic. About 15% showed some decrease in olfactory function and the remaining 25% appeared normal (fell within the normosmic or mildly hyposmic range). Further analysis revealed that of the 40% of patients who could detect olfactory levels of butanol(O.1570 to 0.005%), half were unable to identify the standard number of odor stimuli. This suggests the possibility of a more central type of damage in these patients. A separate group of “surgical anosmics, ” patients lacking olfactory connections as a result of surgical procedure, were also tested and their scores validate the olfactory function test’s ability to define anosmia. All surgical anosmics fell to the left of the control distribution detecting only a 1.3% or stronger solution of butanol. Surgical anosmics were unable to identify any of the odor stimuli. An example of a head injury patient illustrates the application of olfactory function testing in diagnosing and locating neural damage. The patient was a 26-year-old white male involved in a motorcycle accident who sustained a blow to the head. The olfactory function test was administered to the patient and results indicated a detection level within the normal range (0.016% butanol). However, the patient was unable to discriminate any of the odor identification stimuli. In FIGURE 2, a CAT scan of the patient’s head revealed the presence of a large mass (hematoma) in a ventral region of the right frontal lobe (near olfactory pathways). In this case, the patient’s inability

Pediatric Head Injury: A Further Experience

This report consists of 201 patients seen at the Medical College of Virginia from May 1976 to October 1991. They are divided into two groups. The first group is from May 1976 to June 1984 and the second group is from July 1984 to October 1991. The two groups are compared as regards age, Glasgow coma score (GCS), presence of surgical mass lesion, mechanism of injury, intracranial pressure (ICP) course, and outcome. There was a significant difference in the initial GCS between the first and second group with the second group having a lower GCS. In addition, an analysis of the ICP course in group II showed a much lower incidence (5%) of a normal ICP course. There was no difference in outcome between the two groups. The results in the 201 patients are compared to other series.

In vivo Measurement of Brain Water by MRI

A new method for determining brain tissue water using MRI, developed in the laboratory, has been tested and applied to the clinical setting. To evaluate the accuracy of the technique, samples of human brain tissue were harvested from patients scheduled to undergo surgical removal of tumour and in whom biopsies were required for clinical management. MR determined values from imaging water maps compared favourably with gravimetric measures of samples. From these data, we conclude that accurate non-invasive measures of brain oedema in man are now possible.

Craniopharyngioma: Unusual computed tomographic presentation.

Craniopharyngioma usually presents on a computed tomographic (CT) scan as a hypodense or isodense lesion, with calcification, in the suprasellar region. A case with atypical CT findings of a huge, homogeneous, high density, apparently solid, lobulated suprasellar mass is presented. An explanation for the appearance of the tumor is discussed based upon clinical analysis of the tumor contents.