Effect of uridine 5'-diphosphate on cryogenic brain edema in rabbits.

This study was undertaken to examine the effect of uridine 5'-diphosphate, administered intravenously or intraperitoneally, on cold injury-induced brain edema in rabbits. Bolus injection or continuous intravenous infusion of uridine 5'-diphosphate 26 hours after a lesion was established had adverse effects, such as increased intracranial pressure and lowered systolic arterial blood pressure and cerebral perfusion pressure for approximately 10-29 minutes, but these parameters did not change appreciably from 29 minutes to 3 hours after administration. Intraperitoneally administered uridine 5'-diphosphate did not affect these parameters appreciably during 3 hours. Thus, the intravenous administration of uridine 5'-diphosphate is harmful under neurosurgical conditions. In contrast, 10 mg/kg/day i.p. uridine 5'-diphosphate pretreatment and posttreatment, beginning 24 hours before and continuing until 24 hours after the insult, significantly reduced neurologic abnormalities, Evans blue extravasation, water content in the injured gray matter, and intracranial pressure without affecting water content in the white matter. Intravenous dexamethasone pretreatment and posttreatment in this setting significantly reduced only neurologic abnormalities. However, there were no significant differences between intraperitoneal uridine 5'-diphosphate and intravenous dexamethasone effects on cold-injured brain.

Manifestations of Pott's disease in the head and neck.

Tuberculosis (TB) of the spine, or Pott's disease, is a rarely encountered clinical disorder in the United States today. However, Pott's disease should be strongly suspected in a person who presents with a destructive lesion of the spine involving adjacent vertebrae or a retropharyngeal mass which extends across the midline. The most common presenting signs and symptoms are pain and spinal deformity. The PPD skin test is usually positive, but unlike TB of the larynx, the chest roentgenogram is almost always negative. Diagnosis may be confirmed by needle aspiration or incisional biopsy and culture. The otolaryngologic literature has not previously addressed this clinical entity, thus, our experience with a patient with a retropharyngeal mass and quadriplegia diagnosed as Pott's disease will be presented. Subsequent medical therapy, stabilization, and odontoidectomy resulted in resolution of his neurological deficit. The incidence, pathogenesis, clinical features, and management of Pott's disease will be discussed.

Traumatic acute epidural hematoma: unrecognized high lethality in comatose patients.

A series of 51 comatose patients suffering traumatic epidural hematoma after closed head injury is reviewed. This prospective series was accumulated from the National Pilot Traumatic Coma Data Bank during a 2-year period and represents 9% of all patients entered into the Data Bank. The overall mortality was 41%, with 4% remaining in the vegetative state. Fifty per cent of these patients, all of whom were in coma, also had an associated intracerebral contusion. There was no difference in outcome with regard to sex, mode of injury, or the presence or absence of contusion or shift on the computed tomographic (CT) scan. The motor score immediately before operation was the most powerful preoperative predictor of outcome. Sixty-seven per cent or two-thirds of the patients with a motor score of 4, 5, or 6 on the Glasgow coma scale had a satisfactory outcome at last follow-up examination. In contrast, in patients with a motor score of 3 or less, two-thirds either died or remained in a vegetative state. The acute traumatic epidural hematoma is often lethal in the comatose patient. We recommend early evacuation of epidural hematomas, i.e., when they are first noted on the CT scan, rather than waiting for clinical motor deterioration.

Absent or compressed basal cisterns on first CT scan: ominous predictors of outcome in severe head injury.

The relationship of outcome to the appearance of the basal cisterns as seen on initial computerized tomography (CT) scanning was assessed in 218 consecutive severely head-injured patients entered into the second phase of the National Pilot Traumatic Coma Data Bank. Outcome could be directly related to the status of the basal cisterns on the initial CT scan. The mortality rates were 77%, 39%, and 22% among those with absent, compressed, and normal basal cisterns, respectively. This association between cisterns and outcome was shown to be strong after adjusting for Glasgow Coma Scale (GCS) score (p less than 0.001). The state of the cisterns was more important for those with higher GCS scores (scores 6 to 8) than for those with lower scores (scores 3 to 5). Patients with GCS scores of 6 to 8, with cisterns absent or not visualized, suffered nearly a fourfold additional risk of poor outcome, compared to those with normal cisterns. This indicates that the status of the cisterns can be used as an early noninvasive method of identifying patients at high risk of death or severe disability, in whom the initial neurological examination would potentially suggest otherwise.

Comparative responses of cerebellar and cerebral arterioles to changes in PaCO2 in cats.

A modified cranial-window technique was devised that permits direct observation and study of the pial microcirculation of the cerebellum and comparisons of the responses of the microvessels in this location with those in the hemisphere. We used this technique in anesthetized cats to compare the responses of cerebellar and cerebral arterioles with alterations in arterial blood CO2 tension. Arterioles in these two locations responded with similar percentile changes in vessel caliber to both hypercapnia and hypocapnia.

Effect of changes in magnesium ion concentration on cat cerebral arterioles.

The effect of changes in cerebrospinal fluid (CSF) concentration of magnesium ion ([Mg2+]) on pial arterioles was investigated in anesthetized cats equipped with acutely implanted cranial windows for the observation of the pial microcirculation. Increased [Mg2+] caused vasodilation, whereas decreased [Mg2+] caused vasoconstriction. The effect of [Mg2+] was dose dependent and was the same in small and larger arterioles. There was an interaction between CSF [Mg2+] and calcium ion concentration ([Ca2+]), such that the vasodilator effect of Mg2+ was greater when the [Ca2+] was lower, especially in larger vessels. The vasodilator effect of Mg2+ on pial arterioles was enhanced in the presence of the calcium antagonist verapamil (0.5 micrograms/ml), despite the fact that verapamil by itself caused a 12-13% arteriolar dilation. These results show that the vasodilator effect of Mg2+ is probably related to an interaction at the cell membrane resulting in reduction in the influx of Ca2+ into vascular smooth muscle.

Ventriculostomy for hydrocephalus in cerebellar hemorrhage.

In a matter of hours the neurologic status of two hypertensive patients deteriorated to coma. Cranial computed tomography (CT) showed mild to moderate cerebellar hemorrhage and secondary hydrocephalus. Ventriculostomy resulted in clinical improvement within 20 minutes and obviated the need for suboccipital craniectomy. Both patients made a very satisfactory recovery. Similar patients have occasionally been observed by others. Ventriculostomy should be considered for patients with cerebellar hemorrhage who have hydrocephalus by CT scan and undergo progressive neurologic deterioration. Because the frequency of improvement and the risk of upward cerebellar herniation following ventriculostomy is unknown, immediate surgical evacuation of the hemorrhage should be anticipated.

Midbrain lesions: frequent and significant prognostic feature in closed head injury.

Midbrain lesions were found in 23 of 35 autopsied, head-injured people. These lesions were interpreted as "primary"--that is, occurring at the time of impact. This interpretation was concordant with the clinical data, although the difficulty in establishing the precise moment at which the lesions were initiated in any individual case was recognized. Correlative clinicopathological data in head-injured people showed that midbrain damage could be determined by evoked potentials (EPs). In a total of 165 head-injured patients, the early presence or absence of evidence for midbrain lesions on EP examination was a powerful prognostic indicator of death or recovery, respectively. Autopsy and EP data showed that midbrain damage almost always occurred in the presence of hemispheric injury, but this fact should not obscure either the high frequency of midbrain lesions in those dying of head injury or the great prognostic value of their presence or absence.

Reversible brain-stem dysfunction following acute traumatic subdural hematoma: a clinical and electrophysiological study.

Of 366 consecutive patients with severe head injury, treated and managed by a uniform protocol, 61 (17%) were admitted with signs of severe brain-stem dysfunction. Forty-three of the 61 patients (70%) had surgical mass lesions and 30% had diffuse brain damage. Twelve of the 61 patients (20%) survived, but only six patients made a good to moderately disabled recovery. All six of these patients had a traumatic acute subdural hematoma (SDH). The records of the 20 comatose patients with an acute SDH and severe brain-stem dysfunction were reviewed to discover which factors contributed to functional recovery. The average survivor was operated on within 2 1/2 hours after injury and the nonsurvivors within 4 1/2 hours. Prompt surgical intervention and prudent control of postoperative intracranial pressure were major factors in preventing permanent brain-stem damage, with a significance of p less than 0.05 and p less than 0.02, respectively. Measurement of multimodality evoked potentials in the early postoperative period correctly distinguished between reversible and irreversible brain-stem dysfunction in six of the seven patients.

Traumatic acute subdural hematoma: major mortality reduction in comatose patients treated within four hours.

To discover which factors contributed to recovery after surgical intracranial decompression, we reviewed the records of 82 consecutive comatose patients with traumatic acute subdural hematoma (ASDH) who were treated in a single center under a uniform protocol. The delay from injury to operation was the factor of greatest therapeutic importance. Patients who underwent surgery within the first four hours had a 30 per cent mortality rate, as compared with 90 percent in those who had surgery after four hours (P less than 0.0001). Other important prognostic variables included results of the initial neurologic examination, sex, multimodality-evoked potentials, and postoperative intracranial pressure (ICP). If all patients with traumatic ASDH were taken directly to hospitals equipped to diagnose and remove the hematoma within four hours of injury, mortality rates could be reduced considerably.