Biomedical subjects

Georg Leonhardt

Publications and source records attributed to Georg Leonhardt.

7 recordsLinked to original sources

PubMed2006

Thrombolytic therapy in pregnancy.

Pregnancy due to its physiological changes is a procoagulant state. The rate of cardiac valve prosthesis thrombosis, deep venous thrombosis and pulmonary embolism are all increased. Thrombolytic therapy with tissue plasminogen activator (rt-PA) is an approved therapy for ischemic stroke, myocardial infarction, pulmonary embolism and thrombosis of cardiac valve prosthesis. However, there are no data from controlled randomized trials in pregnant patients. Thrombolytic therapy has been rarely used in pregnancy with only 28 cases of rt-PA thrombolysis reported in the literature so far. Indications for rt-PA thrombolysis were stroke (n = 10), thrombosis of cardiac valve prosthesis (n = 7), pulmonary embolism (n = 7), deep venous thrombosis (n = 3), and myocardial infarction (n = 1). Remarkably, all thrombosis of cardiac valve prostheses occurred after switching from warfarin to heparin in order to prevent teratogenicity and fetal loss. Two patients died (7%) and three suffered from complications that were managed conservatively (11%). In another three patients thrombolysis was not successful. Thrombolysis complication rates were similar compared to non-pregnant patients for the above mentioned indications. Six out of the 26 fetus from surviving mothers died (23%), three of them after induced abortion for maternal reasons (12%). A likely causal relation to the prior thrombolysis could only be established in two fetal fatalities (8%). None of the live born children suffered a permanent deficit. Considering that rt-PA does not cross the placenta and taking into account that the complication rates do not exceed those of large randomised controlled trials thrombolytic therapy should not be withheld in pregnant patients in case of life-threatening or potentially debilitating thrombembolic disease.

Adult↗

PubMed2005

[Hypokalemic thyrotoxic periodic paralysis (HTPP). Rare differential diagnosis in case of acute tetraparesis in Europe].

BACKGROUND: Differential diagnosis of acute tetraparesis includes paraplegia caused by trauma, ischemia, inflammation or tumor, Guillain-Barré syndrome, periodic paralysis, myasthenia gravis, and dissociative paralysis. CASE REPORT: The case of a 45-year-old man is reported who noticed weakness of both legs after heavy labor. In the evening he was unable to climb stairs, at night he noticed additional weakness in both arms and dyspnea. After transfer to the authors' department profound tetraparesis, tachycardia and slight dyspnea were found on examination. Cranial nerve examination was unremarkable. Deep tendon reflexes, however, were only slightly diminished. Laboratory work-up revealed hypokalemia (potassium 1.9 mmol/l) and hyperthyreosis. Elevated TRAK and TPO antibodies as well as sonography and scintigraphy of the thyroid gland gave evidence of Graves' disease. After intravenous administration of potassium tetraparesis resolved completely. CONCLUSION: Hypokalemic thyrotoxic periodic paralysis (HTPP), a subtype of hypokalemic paralysis, is unusual in Caucasians. In Asian men the disease is more common. The underlying mechanism is an extra-intracellular shift of potassium in the voluntary muscle cells. In contrast to hereditary autosomal dominant paralyses, a genetic defect is not known. Usually, symptoms of hyperthyreosis in HTPP are mild which can hamper the correct diagnosis.

Acute Disease↗

PubMed2005

Brain perfusion following single seizures.

PURPOSE: The aim of this study was to assess the regional relative interictal and postictal perfusion changes in temporal and parietal lobe epilepsy. METHODS: We investigated interictal and postictal magnet resonance perfusion changes in five patients with temporal lobe epilepsy either with hippocampal sclerosis (n = 3) or without (n = 2), and in one patient with extratemporal (parietal lobe) epilepsy. T(2)*-weighted single-shot echo-planar images were acquired after bolus application of 0.2 mmol/kg gadolinium-diethylene triamine pentaacetic acid (GD-DTPA) at baseline and after intervals of 2-12 min, 15-23 min, 28-50 min, 63-72 min, and 180-240 min. The bolus-peak ratio was calculated in regions of interest in the hippocampus (HIP), parahippocampal gyrus (PHG), thalamus (THA), cortex (COR), and white matter (WM), yielding relative perfusion changes. RESULTS: Interictally, we found relative hyperperfusion of the ictogenic side in five of six patients in the HIP. Postictally, the perfusion decreased in the HIP by 25-39% as compared to baseline, whereas the PHG showed a reverse pattern. In the late postictal phase, perfusion increased in the HIP again and decreased in the PHG. In the THA, the inter- and postictal changes were small (5-19%). COR and WM showed equivocal results. CONCLUSION: Postictal relative hypoperfusion in the HIP appears to be associated with the cessation of neuronal ictal discharge, whereas postictal hyperperfusion in the PHG lags behind and may reflect increased metabolism to restore the interictal state of neuronal excitability.

Adult↗

PubMed2003

Brain diffusion after single seizures.

PURPOSE: Diffusion-weighted magnetic resonance imaging (DWI) after focal status epilepticus has demonstrated focal alterations of the apparent diffusion coefficient (ADC) in the epileptogenic zone. We hypothesized that localized dynamic alterations of brain diffusion during the immediate postictal state will be detectable by serial DWI and correlate with the epileptogenic zone. METHODS: Nine adult patients (four men, five women) with medically intractable epilepsy were prospectively examined with a total of 25 DWI scans taken 2-210 min after a seizure. RESULTS: The interictal ADC was significantly (p < 0.05) elevated in the ictogenic hippocampus in all patients with temporal lobe epilepsy. The following postictal changes of the ADC were seen: (a) decreases by maximally 25-31%, which were most pronounced in the epileptogenic zone (n = 2); (b) generalized ADC changes after generalized seizures (n = 1) or prolonged complex partial seizures (n = 2); (c) no major changes after short-lived seizures or if the time to first DWI scan was >15 min or both (n = 3); and (d) widespread bilateral ADC increases after a flumazenil-induced seizure (n = 1). CONCLUSIONS: ADC changes seen during serial postictal DWI are complex and appear to reflect origin and spread of the preceding seizure. A delineation of the epileptogenic zone appears to be possible only in complex-partial seizures of >60 s duration that do not secondarily generalize.

Adult↗

PubMed2003

Presurgical evaluation of epilepsy by brain diffusion: MR-detected effects of flumazenil on the epileptogenic focus.

PURPOSE: After focal status epilepticus, focal alterations of the apparent diffusion coefficient (ADC) have been demonstrated in the epileptogenic zone by using diffusion-weighted magnetic resonance (MR)imaging (DWI). Effects of flumazenil on an epileptogenic focus have been demonstrated by EEG recordings, but not by functional MRI. We hypothesized that dynamic spatiotemporal alterations of brain diffusion of the epileptogenic focus after application of flumazenil will be detectable by DWI and correlate with the epileptogenic zone. METHODS: Twelve adult patients considered for epilepsy surgery with medically intractable temporal lobe epilepsy (TLE; n = 7), extratemporal lobe epilepsy (ETE; n = 2), and TLE+ETE (n = 3) were prospectively examined with DWI interictally (serving as baseline) and 10 min after application of 1 mg flumazenil i.v. RESULTS: The baseline interictal ADC was significantly elevated in the hippocampus on the ictogenic side in the patients with TLE (p = 0.002) as compared with healthy volunteers. The following changes of the mean ADC were seen in different regions of interest (ROIs) after injection of flumazenil: decreases in the hippocampus on the seizure-onset side by 14.8% (p = 0.005); decreases in the parahippocampal gyrus on both sides by 6.8% (epileptogenic side; p = 0.044) or 7.9% (nonepileptogenic side; NS), respectively; decreases in the cortex on the nonictogenic side by 7.9% (p = 0.047); and no significant changes of the ADC in the other ROIs. CONCLUSIONS: ADC decreases measured after application of flumazenil were seen in the seizure-onset zone as revealed by EEG and structural MRI and are an indicator of focus localization in patients with TLE.

Adult↗

PubMed2002

Clinical outcome and neuropsychological deficits after right decompressive hemicraniectomy in MCA infarction.

BACKGROUND AND PURPOSE: The purpose of this study was to analyse in detail the functional outcome and the neuropsychological deficits in patients with space-occupying infarction of the non-dominant hemisphere one year after surgery. METHODS: Postoperative complications and retrospective consent to surgery were assessed in a semi-structured interview in 26 patients. Functional outcome was measured with the Barthel-Index (BI) and Rankin-Scale. Neuropsychological tests in 14 patients focused on visuo-spatial and visuo-constructive abilities, attention, spatial span and self-rated mood. RESULTS: The one-year survival rate was 69 % (18 of 26). The functional outcome was good (BI >/= 90) in 3 patients, fairly good (BI 75-85) in 6, moderate (BI 30-70) in 6, and poor (BI 0-25) in 3 patients. Age was an independent predictor of outcome, patients above 52 years had a BI of 50 or below. Neuropsychological tests (14 of 18) showed profound attention deficits in all patients, and visuo-spatial and visuo-constructive deficits in patients with lower formal education. Retrospectively, 4 of 18 patients would not give consent to surgery again, mostly because of the bad quality of life postoperatively. CONCLUSION: Older patients do not seem to benefit from decompressive hemicraniectomy; more than half of the surviving younger patients have a good outcome and live independently. Attention deficits are prominent in all patients; visuo-spatial and constructive deficits are less pronounced in patients with higher formal education. Retrospective agreement to decompressive hemicraniectomy is high in patients with good functional outcome.

Adolescent↗

PubMed2002

Brain diffusion during hyperventilation: diffusion-weighted MR-monitoring in patients with temporal lobe epilepsy and in healthy volunteers.

Hyperventilation (HV) can be used to provoke epileptiform activity and occasionally seizures in generalised and in focal epilepsies. Based on the hypothesis that HV might alter brain diffusion in the epileptogenic areas of patients with temporal lobe epilepsy (TLE), we examined these alterations using quantitative diffusion MR imaging (DI) in four patients with TLE and unilateral hippocampal sclerosis (TLE-HS) and six patients with TLE without hippocampal sclerosis (TLE-pure), and in 10 healthy volunteers. Brain diffusion was measured at baseline and immediately after 4 min of HV. In all patients with TLE HV was repeated two times, 4 min each, followed by subsequent DI. The apparent diffusion coefficient (ADC) was quantified in predefined regions of interest. In controls, the ADC did not differ between baseline and HV and between right and left side. Compared to controls TLE-HS patients showed significantly higher ADC at baseline in the hippocampus of the ictogenic side (111+/-13 vs. 87.5+/-4.26 x 10(-5) mm(2)/s, P=0.029). During HV ADC decreased significantly in the ictogenic hippocampus compared to controls (-17.3+/-7.1 vs. -3.34+/-8.7, P=0.004). In TLE-pure patients ADC of the ictogenic hippocampus was higher than in normals (99.3+/-14.2 vs. 87.5+/-4.26 x 10(-5) mm(2)/s, P=0.031) but there was no significant decrease during HV. Serial HV did not further enhance this decrease. No significant HV-induced changes were seen in other brain areas. In conclusion, our results show that HV can induce dynamic changes of brain diffusion in patients with sclerotic hippocampi but not in non-sclerotic hippocampi. These findings may be utilized for lateralisation of the epileptogenic hippocampus during presurgical evaluation of TLE.

Adult↗