Hyperbaric oxygen increases survival following carotid ligation in gerbils.

We studied the effects of graded exposure to hyperbaric (1,875 mm Hg) oxygen therapy in an acute stroke model prepared by unilateral carotid artery interruption in gerbils. Pentobarbital alone, superoxide dismutase alone, two periods of hyperbaric oxygen alone, and each agent combined with hyperbaric oxygen were administered to investigate possible mechanisms of protection from cerebral ischemia. Survival rates and neurologic deficit scores over 5 days in all treated groups were compared with those in a control group. Survival rates in the groups subjected to 2 (63.9 +/- 4.0%) and 4 hours (70.1 +/- 5.2%) of hyperbaric oxygen alone were significantly higher than in the control group (53.6 +/- 4.2%). The group treated with pentobarbital alone also demonstrated increased survival (69.8 +/- 7.0%), but the combination of therapeutic regimens offered no apparent additive protection. By 5 days there were no differences in the neurologic deficit scores of the survivors in the groups. The toxic pulmonary effects of hyperbaric oxygen were assessed in a pilot LD50 study. The pressure used caused no mortality during 4 hours of exposure, and the calculated LD50 was 7.26 hours. This investigation demonstrates that graded doses of hyperbaric oxygen given after the insult increase survival in a gerbil model of stroke.

Videodensitometric estimation of the protective effect of hyperbaric oxygen in the ischemic gerbil brain.

To verify its protective effect on the ischemic mammalian brain, hyperbaric oxygen was administered to six groups of carotid-ligated gerbils. The outcome was evaluated clinically and by a colorimetric videodensitometry technique by comparing differences in the interhemispheric color density through the translucent intact cranium. It was found that there was a graded decrease in interhemispheric differences with increasing exposure to hyperbaric oxygen (the appearance of the ischemic hemisphere increasingly approached that of normal brain). This correlated with the incidence of ischemia in each group.

Fatiguing weakness: an initial symptom in cervical compressive radiculopathy.

Exercise-induced weakness (fatiguing) is described in three patients with cervical compressive radiculopathy. In all three cases, the patients had symptoms only while at work, and in two cases, symptoms occurred in life-threatening situations. All patients had seen several physicians with a functional diagnosis being considered in all cases because of symptoms only at work and the absence of objective findings during examination. Precise history and examination techniques led to the correct diagnosis and treatment after appropriate investigation. The fatiguing weakness in our cases is thought to be a manifestation of early or mild neurologic involvement unmasked by exercise, rather than a manifestation of compression or ischemia.

Evolution of dolichoectasia of the vertebrobasilar system as evidenced by serial computed tomography.

A case of dolichoectasia of the vertebrobasilar system and carotid arteries is presented. Features considered unique to this case include recurrence of trigeminal neuralgia after a standard surgical procedure, presumably caused by rapidly progressing dolichoectasia of the vertebrobasilar arteries, and progressive calcification and ventriculomegaly over the course of one and a half years, shown on sequential computed tomographic (CT) scans. Dolichoectasia is discussed briefly as a clinical entity and its characteristic CT scan findings are reviewed.

Apoplexy in a prolactin microadenoma leading to remission of galactorrhea and amenorrhea.

A 28-year-old woman with bilateral headaches and vomiting was found to have normal prolactin levels despite an eight-year history of intermittent galactorrhea and amenorrhea and the current finding of a pituitary microadenoma. The microadenoma contained hemosiderin. It is concluded that pituitary apoplexy is not confined to large tumors that have outgrown their blood supply, but can occur in microadenomas with regression of a positive endocrinopathy.

Serial phrenic nerve conduction studies in candidates for diaphragm pacing.

Serial phrenic nerve conduction studies in 3 patients with high cervical cord injuries have demonstrated a pattern of function that changes with time. Nerves may be responsive initially and may then become unresponsive only to have responses reappear at a later date. Before a final decision is made about phrenic nerve viability prior to diaphragm pacing, serial studies should be carried out for at least 6 weeks postinjury on initially responsive nerves, and for at least 2 years postinjury on nonresponsive nerves or those with a changing functional pattern.

Persistent isodense intraventricular hematoma caused by intraventricular saccular aneurysm.

A case of intraventricular hemorrhage secondary to an intraventricular saccular aneurysm is presented in which the hematoma mass gave a false appearance of resolution secondary to its progressive isodense appearance on serial computerized cranial tomograms. Intraventricular saccular aneurysms are unusual lesions and a most uncommon cause of intraventricular hemorrhage. Diagnosis of intraventricular hemorrhage has been greatly facilitated since the advent of cranial computerized tomography though elucidation of the definitive cause of hemorrhage in this case still depended upon cerebral angiography. In addition, the development of isodensity by the hematoma mass on serial computed tomograms has led to this case report.

Hyperprolactinemia from radiation-induced hypothalamic hypopituitarism.

In 1975 Samaan et al described the effects of radiation damage of the hypothalamus in 15 patients with head and neck cancer. Shalet et al in 1977 described endocrine morbidity in adults who as children had been irradiated for brain tumors. This report describes instances of hyperprolactinemia and associated hypothalamic, pituitary, and thyroid dysfunction following irradiation of a young adult female for brain neoplasia.

Fentanyl concentrations in brain and serum during respiratory acid--base changes in the dog.

It is a clinical impression that less fentanyl is needed for anesthesia during hyperventilation and hypocarbia. If true, it might be due to both increased penetration of fentanyl, a highly lipid-soluble agent, into the brain and increased brain tissue binding. Serum and brain concentrations of fentanyl were determined in dogs anesthetized with halothane during normocarbia, hypocarbia by hyperventilation, and hypercarbia by addition of CO2 to the inspired mixture. Fentanyl, 12.5 micrograms/kg, was injected iv, and serum and brain samples were taken for fentanyl analysis by radioimmunoassay. Brain fentanyl values peaked latest (15--20 min) and were highest during hypocarbia; brain fentanyl values peaked earliest (0--5 min) and were lowest during hypercarbia; values during normocarbia were intermediate in time to peak (10--15 min) and concentration. Thereafter, brain levels declined, but during hypocarbia were significantly higher and during hypercarbia were significantly lower than during normocarbia. Interestingly, serum fentanyl levels were also significantly higher during hypocarbia. The brain--blood fentanyl ratios for each of the three CO2 levels increased for 30 min and thereafter stayed relatively constant. The brain--blood ratios were highest with hypocarbia and lowest with hypercarbia. At 35 min, when clinical analgesia may be considered terminated, hypocarbic brain levels were double those of normocarbia. The authors feel this reflects, to a large extent, higher serum fentanyl concentrations and delayed cerebral wash-out because of decreased blood flow. To a small but unknown extent the higher brain fentanyl levels result from increased brain--blood penetration due to increased lipid solubility, and increased brain tissue binding of fentanyl during respiratory alkalosis.

Thoracic disc herniation. Treatment and prognosis.

Thoracic disc herniation is difficult to recognize. Diagnosis is easily made when the patient has a paraparesis, but at this point the disc herniation is usually large, and the result of the disc removal is less certain. Most of the 7 patients discussed had an early diagnosis made. Six patients were treated by the transthoracic anterolateral approach, and improvement occurred in all.

Phrenic nerve conduction studies in the evaluation of ventilatory problems in patients with cranio-cervical trauma.

Five patients with hypoventilation and paresis of the diaphragm following trauma to the cervical spinal cord, brain stem, or both, were evaluated with phrenic nerve conduction studies while being considered for implantation of a phrenic nerve stimulator. Several distinct patterns of phrenic nerve function were elicited in the various cases, allowing accurate predictions and management decisions to be made. Phrenic nerve conduction studies are felt to be a valuable diagnostic tool in the management of the hypoventilating patient with cranio-cervical trauma. The procedure is safe, rapid, and easily performed at the bedside.

Delayed evolution of posttraumatic subdural hygroma.

Five hundred and forty-six patients in a consecutive series of 1,601 patients with craniocerebral trauma had computed tomography. One hundred and ninety-six patients had a follow-up CT scan. Thirteen patients (6.6%) developed apparently "silent" subdural hygromas of delayed evolution noted from six to 46 days after injury (average 22 days). Three of 10 patients (30%) improved after operation. No patient with a severe cerebral deficit (decortication or decerebration) improved. The three unoperated hygromas and the six that persisted after operation tended to resolve spontaneously. The infrequent and modest improvement following surgical treatment and the tendency to spontaneous resolution suggest that operation may be unnecessary in many patients with posttraumatic subdural hygroma of delayed evolution.

Effect on canine cerebral blood flow of two common pressor agents during prolonged halothane anesthesia.

Inasmuch as prolonged halothane anesthesia is often associated with hypotension, the effects of pressor agents possibly employed to adjust this hypotension on cerebral blood flow are of interest. In dogs, after prolonged halothane anesthesia, there was a marked difference in the effects of phenylephrine and angiotensin on cerebral blood flow at dosages which promote moderate rises in blood pressure. Phenylephrine had no effect whereas angiotensin had a significantly enhancing effect on cerebral blood flow.

Dose dependency of the post-insult protective effect of pentobarbital in the canine experimental stroke model.

In a canine stroke model, dose dependent protection by postocclusion pentobarbital was suggested from 10--40 mg/kg. In 28 dogs investigated (10 from a previous study) a distinct, significant reduction in right cerebral hemisphere infarction occurred in animals given 15--20 mg/kg pentobarbital intramuscularly 1 hour postocclusion. Increased dosages did not alter statistically the infarct size and 2 dogs at the 50 mg/kg and 80 mg/kg levels died of barbiturate-induced respiratory failure.

Focal eosinophilic granuloma of the temporal lobe. Case report.

The authors describe the clinical, pathological, and therapeutic aspects of a case of focal temporal lobe eosinophilic granuloma, presenting with otitis media and meningitis, and evolving subsequently into a temporal lobe mass. This triad, otitis media, meningitis, focal cerebral lesion with systemic manifestations of inflammation, eosinophilia of blood and cerebrospinal fluid, should suggest eosinophilic granuloma in the differential diagnosis. The lesion is sensitive to relatively small doses of radiation.

External carotid-vertebral artery anastomosis for vertebrobasilar insufficiency.

Two patients with previous brain stem infarction and current symptoms of vascular insufficiency in the basilar circulation had evidence of vertebral artery occlusive disease. Angiography demonstrated ostial stenosis of the dominant right vertebral artery and retrograde flow down the left vertebral artery to the level of the transverse process of C2 in the first case and to the level of a severely stenosed origin in the second case. Carotid circulation was patent in both cases. The blood flow in the posterior circulation was patent in both cases. The blood flow in the posterior circulation was augumented by extracranial anastomosis of the external carotid artery to the vertebral artery in the foramen transversarium at the level of C1-2 by a lateral approach in Case 1 and at the level of C4-5 by an anterior approach in Case 2. Postoperative improvement in neurologic status occurred in both cases.