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Biomedical subjects

D Krieger

Publications and source records attributed to D Krieger.

At least 19 recordsLinked to original sources
PubMed1999

Surgical and medical management of patients with massive cerebellar infarctions: results of the German-Austrian Cerebellar Infarction Study.

Surgical intervention (ventricular drainage or decompressive craniotomy) may be necessary in patients with cerebellar infarction if mass effect develops. However, patient selection and timing of surgery remain controversial, and there are few data on clinical signs in the early course that are predictive for outcome. The clinical course and neuroradiological features of 84 patients (aged 22-78, mean 58.5 years) with massive cerebellar infarction confirmed by computed tomography were prospectively observed for 21 days after admission and at 3-month follow-up using a standardized protocol. Data were gathered from 1992 to 1996 in 17 centers. The patients were assigned to three treatment groups depending on the decision of the primary caretaker: 34 underwent craniotomy and evacuation, 14 received ventriculostomy, and 36 were treated medically. Treatment groups differed regarding the level of consciousness, signs of mass effect in computed tomography and signs of brainstem involvement. The overall risk for poor outcome depended on the level of consciousness after clinical deterioration (odds ratio = 2.8). Subgroup analysis of awake/drowsy or somnolent/stupor patients revealed no relationship to treatment. The vascular territory involved did not affect outcome. Surgical treatment for massive cerebellar infarctions was not found to be superior to medical treatment in awake/drowsy or somnolent/stupor patients. Half of all patients deteriorating to coma treated with ventricular drainage or decompressive craniotomy had a meaningful recovery. We were unable to compare surgical versus medical therapy in this subgroup due to lack of control group. This study supports the notion that the level of consciousness is the most powerful predictor of outcome, superior to any other clinical sign and treatment assignment. Deterioration of consciousness typically occurred between days 2 and 4, with a maximum on day 3.

Adult↗
PubMed1998

Manganese augments nitric oxide synthesis in murine astrocytes: a new pathogenetic mechanism in manganism?

Since manganese (Mn2+) is known to be sequestered in glial cells, we investigated possible neurotoxic mechanisms involving astrocytes in vitro. Low concentrations of Mn2+ were toxic only in astrocyte-neuronal cocultures but not in pure astrocyte or neuronal cultures. As a possible mediator of manganese-derived neurotoxicity, we measured the production of nitric oxide in astrocytes. Manganese, but not other transition metals, dose dependently increased iNOS mRNA and protein levels and the release of nitric oxide in activated astrocytes. This effect was specific for astrocytes, since we observed no stimulation in microglial cells. The observations suggest that besides the known inhibition of mitochondrial function the neurotoxic effect of manganese in low concentrations might be mediated by the increased production of nitric oxide in astrocytes.

Animals↗
PubMed1998

Intravenous tissue plasminogen activator for acute ischemic stroke: feasibility, safety, and efficacy in the first year of clinical practice.

BACKGROUND AND PURPOSE: The feasibility, safety, and efficacy of intravenous tissue plasminogen activator (t-PA) for patients with acute ischemic stroke in clinical practice need to be assessed. METHODS: We initiated a prospective open-label study at a university hospital and two community hospitals in Houston, Tex, immediately after the publication of the National Institute of Neurological Disorders and Stroke (NINDS) t-PA study. A total of 30 patients, age 32 to 90 years, were treated with 0.9 mg/kg of intravenous t-PA (maximum dose, 90 mg) within 3 hours of acute ischemic stroke between December 1995 and December 1996. RESULTS: Six percent (6%) of all patients hospitalized with ischemic stroke received intravenous t-PA at the university hospital and 1.1% at the community hospitals. The rates of total, symptomatic, and fatal intracerebral hemorrhage were 10%, 7%, and 3%. Thirty-seven percent (37%) of patients recovered to fully independent function. The average time from stroke onset to emergency department arrival was 57 minutes; emergency department arrival to computed tomography scan 41 minutes; and computed tomography scan to administration of treatment 59 minutes. CONCLUSIONS: When treatment guidelines are carefully followed in an urban hospital setting, intravenous t-PA for acute ischemic stroke is feasible and shows safety and efficacy comparable to the results of the NINDS study.

Activities of Daily Living↗
PubMed1997

Haematoma evacuation does not improve outcome in spontaneous supratentorial intracerebral haemorrhage: a case-control study.

Surgical intervention in supratentorial intracerebral haemorrhage (ICH) is still controversial. We assessed the value of haematoma evacuation with a case-control study. 145 consecutive patients with supratentorial spontaneous ICH without tumour or vascular abnormalities were analysed. Haematoma evacuation was performed in 24 patients. Age, sex, Glasgow Coma Scale (GCS), level of consciousness, pupillary reaction on admission, localisation, aetiology and volume of the haematoma, presence of ventricular blood, and Glasgow Outcome Scale (GOS) on discharge were analysed. From statistical analysis 40 patients > 80 years and with haematoma volume < 10 ml, who were always treated conservatively, were excluded. Prognostic factors retained from a multiple regression model with the dichotomised GOS scale (GOS 1-3, 4 + 5) as response variable were GCS, haematoma volume and location. The only difference between all medically treated and "operated" patients was haematoma volume, which was larger in the "operated" patients. All 24 evacuated cases could be matched to a medically treated control regarding age, haematoma volume and location, GCS, and pupillary reaction. Significant differences between the two groups could not be detected. Outcome was not different between the two groups. After separating the sample into patients with and without ventricular haemorrhage, there was no different outcome between the two groups either. We conclude that haematoma evacuation did not improve outcome in supratentorial spontaneous ICH. Since haematomas were evacuated mainly in clinically deteriorating patients, our data suggest that the only effect of haematoma evacuation is to stop progressive deterioration rather than to improve overall clinical outcome.

Adult↗
PubMed1997

MRI findings in chronic hepatic encephalopathy depend on portosystemic shunt: results of a controlled prospective clinical investigation.

BACKGROUND/AIMS: Deterioration of hepatic encephalopathy is a major concern with the transjugular intrahepatic portosystemic shunt procedure. Symmetric hyperintense globus pallidus on T1-weighted cranial magnetic resonance imaging in patients with liver cirrhosis anticipates hepatocerebral disease. It is hypothesized that hepatic encephalopathy and basal ganglia signal intensity progress in patients with cirrhosis of the liver undergoing transjugular intrahepatic portosystemic shunt. METHODS: Twenty-four patients were randomized to undergo either transjugular intrahepatic portosystemic shunt or elective sclerotherapy. At study entry and 6 months after randomization, neurologic assessment, psychometric tests, standard EEG, and magnetic resonance imaging were performed. The severity of liver failure was graded using Child-Pugh's classification. The signal intensity of the globus pallidus was determined on sagittal T1-weighted magnetic resonance imaging. RESULTS: The T1-weighted signal intensity of the globus pallidus on magnetic resonance imaging significantly increased after transjugular intrahepatic portosystemic shunt placement (p<0.01), but not with elective sclerotherapy. At follow-up, neurological symptoms indicating decline of mental status and motor performance were somewhat more prevalent in transjugular intrahepatic portosystemic shunt patients. Significant deterioration of EEG abnormalities occurred in patients treated with transjugular intrahepatic portosystemic shunt as opposed to elective sclerotherapy (p<0.01). CONCLUSIONS: Transjugular intrahepatic portosystemic shunt procedure increases hyperresonant globus pallidus on magnetic resonance imaging. Neuropsychiatric evaluation shows advancing hepatic encephalopathy, in particular with transjugular intrahepatic portosystemic shunt; however, it does not parallel the augmentation of pallidal signal intensity on magnetic resonance imaging.

Adult↗
PubMed1997

Serum neuron-specific enolase as early predictor of outcome after cardiac arrest.

OBJECTIVE: To examine the prognostic value of serum neuron-specific enolase for early prediction of outcome in patients at risk for anoxic encephalopathy after cardiac arrest. DESIGN: Prospective study. SETTING: Coronary intensive care unit of the University of Heidelberg. PATIENTS: Forty-three patients (66.8 +/- 12.7 [SD] yrs, range 33 to 85) who had had either primary or secondary cardiac arrest, followed by cardiopulmonary resuscitation (CPR). INTERVENTIONS: Serial blood samples and clinical examinations. MEASUREMENTS AND MAIN RESULTS: Serum neuron-specific enolase concentrations were determined after CPR on 7 consecutive days. Twenty-five patients remained comatose and subsequently died; 18 patients survived the first 3 months and had no relevant functional deficit at 3-month follow-up. Neuron-specific enolase concentrations were correlated with neurologic outcome. Concentrations of >33 ng/mL predicted persistent coma with a high specificity (100%) and a positive predictive value of 100%. Overall sensitivity was 80%, with a negative predictive value of 78%. Serum concentrations of neuron-specific enolase exceeded this cutoff value no more than 3 days after cardiac arrest in 95% of patients in whom these concentrations had exceeded 33 ng/mL. CONCLUSIONS: In patients who have been resuscitated after cardiac arrest, serum neuron-specific enolase concentrations of >33 ng/mL predict persistent coma with a high specificity. Values below this cutoff level do not necessarily indicate complete recovery, because this method has a sensitivity of 80%.

Adult↗
PubMed1996

Neuropsychiatric profile and hyperintense globus pallidus on T1-weighted magnetic resonance images in liver cirrhosis.

BACKGROUND & AIMS: Hyperintense globus pallidus on T1-weighted magnetic resonance images (MRIs) in cirrhotic patients are reported to reflect severity of liver disease; however, their consequence for hepatic encephalopathy is unknown. The aim of this study was to outline a pattern of neuropsychiatric abnormalities in chronic liver failure and its correlation with MRI findings. METHODS: Fifty-one consecutive patients were enrolled in the study. Neuropsychiatric assessment used a standardized protocol, including dichotomized neurological parameters, brief psychiatric rating and psychometric tests, as well as electroencephalography. The severity of liver failure was graded using standard laboratory parameters and the Child-Pugh's classification. Signal intensity of the globus pallidus was determined on sagittal T1-weighted MRIs. RESULTS: Two aspects of neurological dysfunction could be distinguished by principal components analysis: impairment of complex cerebral function and subcortical motor performance. Both neurological categories correlated with severity of liver failure, grade of electroencephalographic abnormalities, and psychometric test results. Additionally, prior bouts of overt encephalopathy indicate progressive dementia. T1-weighted globus pallidus signal intensity did not correlate with any clinical or laboratory test result. CONCLUSIONS: This study shows a characteristic pattern of neurological findings in patients with liver failure and hyperintense globus pallidus on T1-weighted MRIs. Although neurological dysfunction parallels hepatic failure, MRI abnormalities of basal ganglia do not indicate severity of actual hepatic encephalopathy.

Adolescent↗
PubMed1996

A novel two-nucleotide deletion in the ornithine transcarbamylase gene causing fatal hyperammonia in early pregnancy.

Ornithine transcarbamylase (OTC) deficiency shows X-linked inheritance. Typically, symptomatic females (who constitute 15%-20% of all carriers) have markedly reduced enzyme activity and show first symptoms in late infancy or early childhood. Here we present the case of a previously asymptomatic 24-year-old woman who died of severe hyperammonemia associated with orotic aciduria but normal OTC activity in the fourth month of pregnancy. DNA analysis revealed a novel mutation in form of the deletion of two nucleotides (T892, G893) in exon 9 of the OTC gene, leading to a frame shift and an aberrant gene product. We suggest that OTC deficiency should be suspected in any patient who presents with hyperammonia in the presence of otherwise normal liver function.

Adult↗
PubMed1996

Critical illness polyneuropathy: clinical findings and outcomes of a frequent cause of neuromuscular weaning failure.

OBJECTIVE: To describe clinical and electrophysiologic features and outcomes of critically ill patients with neuromuscular causes of failure to wean from mechanical ventilator support. DESIGN: A prospective, consecutive, case series. SETTING: Neurological, neurosurgical, and medical intensive care units in a university hospital. PATIENTS: Seven patients during a 3-yr period with failure to wean from mechanical ventilation not explained by pulmonary complications. INTERVENTIONS: Muscle and nerve biopsy in three patients. MEASUREMENTS AND MAIN RESULTS: Detailed electrodiagnostic studies were done in all patients 3 to 6 wks (median 4.5) after the onset of the acute illness and were repeated 3 months to 3.5 yrs later in those patients who survived. Primary illnesses included various intracranial and medical conditions. All patients had moderate-to-severe limb weakness with marked muscle atrophy. Tendon reflexes were decreased in three patients, exaggerated in two patients with intracranial lesions, and absent in two patients. Electromyography demonstrated severe acute denervation, with striking involvement of proximal muscles. Muscle and nerve biopsies showed severe neurogenic atrophy and axonal degeneration without inflammation. There was no evidence of primary myopathy. Two patients died of complications of sepsis. Of the survivors, three patients had no further weakness at the time of reexamination, except for peroneal nerve palsy in one patient. Two patients, still in the recovery period, showed markedly improved conditions but still showed slight weakness of the proximal muscles. By electrophysiology, signs of chronic neurogenic damage were demonstrable in all survivors at follow-up. CONCLUSIONS: Critical illness polyneuropathy is a frequent cause of neuromuscular weaning failure in critically ill patients, regardless of the type of primary illness. Involvement of proximal (including facial and paraspinal) muscles is striking. Tendon reflexes are often preserved. Patients with central nervous system injury may likewise develop critical illness polyneuropathy. In these latter patients, tendon reflexes may even be exaggerated. Recovery from critical illness polyneuropathy is usually rapid and clinically complete, although incomplete on electrodiagnostic study. Residual peripheral nerve lesion, generally of the peroneal nerve, is the most frequent feature of incomplete recovery. The need for careful electrophysiologic testing is emphasized to clarify the nature and extent of neuromuscular disturbances in critically ill patients. Failure to recognize the development of neuropathy in these patients may lead to erroneous conclusions about the ability to wean them from the ventilator.

Adult↗
PubMed1996

Cortical hyperintensity on proton density-weighted images: An MR sign of cyclosporine-related encephalopathy.

PURPOSE: To describe cortical hyperintensities in proton density-weighted images in six patients with presumed cyclosporine-induced neurotoxicity. METHODS: In six patients with clinical evidence of cyclosporine-related encephalopathy, MR imaging was performed after the onset of symptoms and signs (mean, 24 days after liver transplantation). Five of these patients had serial MR imaging for a period that varied from 2 to 20 months. Along with the imaging studies, the patients' clinical status was evaluated and various laboratory parameters, including blood pressure and levels of cyclosporine, cholesterol, and magnesium, were monitored. RESULTS: In all six patients, initial MR studies showed hyperintensity of several cerebral gyri that was unequivocal only on proton density-weighted images. Although in five patients these signal abnormalities were limited to the cortex, one patient had increased signal in the subjacent white matter as well. In one patient, the images were also remarkable for areas of cortical hyperintensities on T1-weighted images. In another patient, cortical enhancement occurred after administration of gadopentetate dimeglumine, with a normal cortical signal on the precontrast images. The abnormal cortical signal began to fade after cyclosporine reduction, but in two patients it remained visible for at least 20 months. The neurologic symptomatology associated with cyclosporine-induced neurotoxicity included seizures (three patients), speech disorder (three patients), and disturbance of consciousness (three patients). CONCLUSION: Cyclosporine-induced neurotoxicity occurring in patients after liver transplantation appears to affect the cerebral cortex preferentially. Because its MR equivalent resembles changes resulting from hypoxic injury or cortically centered vasculitis, we suspect the underlying mechanism may be a vascular injury that results in cortical hypoperfusion.

Adolescent↗
PubMed1995

Manganese and chronic hepatic encephalopathy.

Clinical observations and animal studies have raised the hypothesis that increased concentrations of manganese (Mn) in whole blood might lead to accumulation of this metal within the basal ganglia in patients with end-stage liver disease. We studied ten patients with liver failure (and ten controls) by magnetic resonance imaging (MRI) and measurement of Mn in brain tissue of three patients who died of progressive liver failure (and three controls) was also done. Whole blood Mn concentrations in patients with liver cirrhosis were significantly increased (median 34.4 micrograms/L vs 10.3 micrograms/L in controls; p = 0.0004) and pallidal signal intensity indices correlated with blood Mn (Rs = 0.8, p = 0.0058). Brain tissue samples reveal highest Mn concentrations in the caudate nucleus, followed by the quadrigeminal plate and globus pallidus. Mn accumulates within the basal ganglia in liver cirrhosis. Similarities between Mn neurotoxicity and chronic hepatic encephalopathy suggest that this metal may have a role in the pathogenesis of chronic hepatic encephalopathy. Further studies are warranted because the use of chelating agents could prove to be a new therapeutic option to prevent or reverse this neuropsychiatric syndrome.

Adult↗