1/4. Broadening the clinical spectrum: unusual presentation of spontaneous cerebrospinal fluid hypovolemia. Case report.The syndrome of spontaneous intracranial hypotension is characterized by orthostatic headaches in conjunction with reduced cerebrospinal fluid (CSF) pressure or CSF volume, and characteristic magnetic resonance (MR) imaging findings. A 50-year-old man presented with a 1-year history of paroxysmal ataxia of gait and short attacks of blurred vision when he stood up from a recumbent position and began to walk. Orthostatic headache was not a feature of his clinical presentation. Magnetic resonance images of the brain revealed diffuse enhancement of the dura mater and hygromas over both cerebral convexities. Magnetic resonance images of the spine demonstrated dilated cervical epidural veins and dilation of the perimedullary veins. Radionuclide cisternography identified a CSF leakage that was localized to the T12-L1 level on subsequent myelograms and on computerized tomography scans obtained after the myelograms. An epidural blood patch was administered and visualized with tungsten powder. The patient's clinical symptoms and sites of disease on imaging completely resolved. The unusual clinical presentation in this case--paroxysmal ataxia of gait, lack of orthostatic headaches, and dilated epidural and perimedullary venous plexus--supports a recently noted broadening of both the clinical and imaging characteristics of spontaneous intracranial hypovolemia.- - - - - - - - - - ranking = 1keywords = pressure (Clic here for more details about this article) |
2/4. Sudden blindness caused by anterior ischemic optic neuropathy in 5 children on continuous peritoneal dialysis.The authors report the occurrence of sudden blindness in 5 children (mean age, 32 months; range, 11 to 60) during continuous peritoneal dialysis regimen. All children presented with loss of light perception, visual fixation and ocular pursuit, and bilateral mydriasis unreactive to bright light. Fundoscopic examination found signs of anterior ischemic optic neuropathy with disc swelling, edema, and hemorrhages. Whereas 1 patient was dehydrated, the 4 other patients appeared well and not dehydrated. Nevertheless, blood pressure was below the normal range in all of them. Therefore, hypovolemia is highly suspected to have been the cause of ischemic optic neuropathy in all cases. Treatment consisted of steroids (4 patients), anticoagulation or antiagregation drugs (3 patients), plasma or macromolecules infusions (2 patients), vasodilatators (2 patients), and transient dialysis interruption (1 patient). One child with hepatic cirrhosis died 4 days later of acute liver insufficiency owing to ischemic hepatic necrosis. The other children had only partial improvement of vision during the following months. Because the prognosis of ischemic optic neuropathy is very poor, diagnosis and treatment of chronic hypovolemia in children on continuous peritoneal dialysis is essential to prevent such a devastating complication.- - - - - - - - - - ranking = 1keywords = pressure (Clic here for more details about this article) |
3/4. Volume expansion during neonatal intensive care: do we know what we are doing?Although volume expansion is liberally used in newborn intensive care, we know little about its effects on hemodynamics or outcomes. Given appropriately to a truly hypovolemic baby, it can be life-saving, but the clinical diagnosis of hypovolemia is probably very inaccurate. We know that volume expansion has less effect on blood pressure than dopamine, and although it seems to produce immediate increases in systemic blood flow, we do not know for how long these increases are sustained. There is evidence to show that the routine use of volume expansion in preterm babies has no effect on outcome, and there is little evidence to support its routine use during resuscitation or the treatment of metabolic acidosis. Whether crystalloids or colloids are preferable is also unclear in newborns. In situations of concern related to circulatory compromise, if possible, define the hemodynamics echocardiographically. Otherwise, if in doubt, some volume should be given, although it is probably unwise to keep expanding the volume if this is not improving physiologic (blood pressure and heart rate) or echocardiographic systemic blood flow parameters.- - - - - - - - - - ranking = 2keywords = pressure (Clic here for more details about this article) |
4/4. Variable systolic pressure variation and dynamic hyperinflation due to an intrabronchial tumor.Systolic pressure variation (SPV) is the cyclic change in systolic blood pressure secondary to positive-pressure ventilation. It is normally a good indicator of intravascular volume and often can be substituted for central venous pressure monitoring, but the reliability of SPV for this use depends on the multiple determinants of intrathoracic pressure remaining constant. We present a case in which an intrabronchial tumor caused dynamic hyperinflation of one lung. This situation, in turn, caused a marked increase in SPV but, more importantly, it increased variability of the SPV despite normal intravascular volume. We discuss the physiology of SPV and the implications of this case for the use of SPV as a monitor of intravascular volume.- - - - - - - - - - ranking = 9keywords = pressure (Clic here for more details about this article) |