Peripheral and central nervous system alterations in hypothyroidism: electrophysiological findings

The purpose of this study is to evaluate objectively the functional changes in the nervous system in hypothyroidism by different electrophysiological parameters and to determine the frequencies of these changes in patients with hypothyroidism. We enrolled 23 patients (17-64 years old, mean 38.2) with biochemical evidence of hypothyroidism, with thyroxine less than 4 microg/dl and thyrotropin above 4.5 mU/ml, and 200 age- and sex-matched normal subjects. Detailed clinical examination and electrophysiological measurements included electromyography, motor conduction velocity, visual-evoked potentials (VEPs), brainstem auditory-evoked potentials (BAEPs) and event-related potentials. Determinations of P300, Wechsler Adult Intelligence Scale (IQ) and electroencephalography (EEG) were performed. Of the hypothyroid patients 52% had peripheral nervous system (PNS) involvement. Entrapment neuropathy was the commonest (35%). Axonal neuropathy was recorded in 9% and myopathy was recorded in another 9%. The central nervous system (CNS) was affected in 78% of the cases. Significant prolongations of P100 latency of VEP, latency and interpeak latency of BAEPs of different waves of hypothyroid patients were compared to the control group. 52% had abnormal VEPs and BAEPs above the mean +/- 2 SD of the normal control group. Six patients (26%) had prolonged P300 latency while 16 patients had an IQ below 90. Eight patients (35%) had EEG changes. Diffuse slowing of background activity was the commonest. No significant correlation was observed between hormonal levels and the different electrophysiological parameters. Thus, the CNS is more vulnerable to the effect of hypothyroidism than the PNS. Therefore, we suggest performing electrophysiological studies in hypothyroid patients, even in the asymptomatic ones, early in the course of disease in order to detect the nervous system involvement.     

Intracranial hydatid cyst: contribution of scanography

We reviewed 14 cases of intracranial hydatid cysts, describing the clinical features and radiographic findings. The clinical presentation was dominated by signs of increased intracranial pressure and neurological manifestations. Diagnosis was established on the basis of CT findings, most valuable as a diagnostic tool.     

A rare primitive neuroectodermal tumor: the medulloepithelioma

Primitive neuroectodermal tumors (PNET) is a name used to describe rare and highly malignant tumors composed of undifferentiated cells resembling germinal or matrix cells of the embryonic neural tube. These tumors occur most commonly in the first decade of life, and have a particular radiological, histological and evolution features. We report a case of a PNET in an 8-year-old boy who presented intracranial hypertension studied with computed tomography scan, which demonstrated a sharply circumscribed expansive mass in the frontoparietal deep white matter, with a large cystic component, which was considered at first as a glial tumor. It was treated by total excision, and the histologic study demonstrated a medulloepithelioma. We studied the concept of PNET and their pathological, radiological and prognostic features.     

Tumor-like tuberculosis of the sacrum

Isolated tuberculosis of the sacrum in a 43-year-old woman manifested as functional impairment of the right lower limb. Sacral tuberculosis is rare in patients with no history of tuberculosis. Another unusual feature was the tumor-like aspect of the lesion, with diffuse, ill-defined osteolysis of a large part of the sacrum and extension to the presacral soft tissues responsible for rectal displacement.     

In vitro evaluation of the accuracy of open-configuration MRI in endovascular techniques

The purpose of this study was to determine the accuracy of an interventional magnetic resonance imaging (iMRI) system to position an endovascular catheter in an in vitro model that simulated an infrarenal aortic aneurysm. Adequate visualization of abdominal aortic aneurysms (AAAs) was shown previously in humans. A dedicated near-real-time imaging protocol readily available on a Signa SP 0.5T open configuration MRI unit (General Electric Medical Systems, Milwaukee, WI, USA) was used to image the AAAs of ten human volunteers. A pulsatile in vitro model that simulated an AAA was built, which included the kidneys, the renal arteries, the aorta, and the iliac arteries. A catheter was advanced to a predetermined target through one of the iliac limbs of the model. Using two different techniques, the accuracy with which an interventionist could position the endovascular catheter under the near-real-time guidance of the iMRI system was evaluated. The AAAs of all ten patients were visualized, including the aneurysm wall, the thrombus within it, and the residual lumen, while maintaining adequate contrast, signal, and imaging speed. The position of the catheter was evaluated on target in 42 in vitro procedures. This series of tests showed an average accuracy of 1 mm for catheter positioning. The near-real-time imaging mode of the iMRI system enabled satisfactory evaluation of human AAAs, and it showed great accuracy for catheter positioning in the in vitro model. These results provide optimism regarding the potential of iMRI in endovascular surgery.     

Extra-adrenal pheochromocytoma discovered peroperatively

In this study, an uncommon case has been reported of an ectopic pheochromocytoma without the presence of any clinical symptoms. The radiological investigations showed a right retroperitoneal tumor without any kidney involvement. The diagnosis was established by biopsy and subsequent histological findings. In the course of surgery as the large tumor mass was being removed, tachycardia was observed which caused the resection to be performed as rapidly as possible. Once the tumor had been removed, bradycardia occurred, followed by cardiac arrest: although the latter was stabilized after cardiac massage, the patient died one hour after the operative field had been closed. In addition to this case report, the diagnosis, therapeutic strategy and prognosis regarding an ectopically located pheochromocytoma have been discussed.     

Cortical Na+,K+-ATPase activity, abundance and distribution after in vivo renal ischemia without reperfusion in rats

The aim of our work was to study the changes in activity, abundance and distribution of sodium, potassium-adenosine triphosphatase (Na+,K+-ATPase) in membranes of cortical tubular cells in an in vivo model of ischemic injury without reperfusion. Na+,K+-ATPase, alkaline phosphatase (AP) activities and their distribution in membranes isolated from renal cortex using a Percoll gradient were studied after different ischemic periods. Na+,K+-ATPase alpha-subunit protein abundance was analysed by Western-blot. Plasma urea and cortical adenosine 5' triphosphate (ATP) were also measured. In cortical homogenates 5 min of ischemia promoted a diminution in ATP content. Na+,K+-ATPase activity diminished after 40 min and AP after 100 min of ischemia. Na+,K+-ATPase activity in the Percoll gradient fractions after 5 min peaked at a higher density and was significantly decreased after 40 min. AP activity was decreased in typically enriched apical membranes after both times of ischemia. At each time studied Na+,K+-ATPase abundance was increased in cortical homogenates and membranes. Our results showed opposite effects of ischemia on Na+,K+-ATPase activity and abundance. Increased levels of Na+,K+-ATPase protein were observed. The enzyme would be rapidly delivered to membrane domains and become inactivated as ischemia persists.