1/5. subarachnoid hemorrhage following permissive hypercapnia in a patient with severe acute asthma.In this article, we describe a case of a subarachnoid hemorrhage (SAH) in an acute severe asthma patient following mechanical hypoventilation. A 49-year-old man was admitted to an intensive care Unit with an acute exacerbation of asthma. After 3 days of mechanical ventilation (hypercapnia and normoxaemia), it was noted that his right pupil was fixed, dilated, and unreactive to light. Computed tomography (CT) scan showed localized SAH within the basilar cisterns and diffuse cerebral swelling. On the fourth day, a new CT scan showed hemorrhage resorption and a cerebral swelling decrease. In the following days, the patient's condition continued improving with no detectable neurological deficits. A review of similar published reports showed that all patients performed respiratory acidosis, normoxaemia, and hypercapnia. The most frequent neurological sign was mydriasis, and all subjects showed cerebral edema. Since normoxaemic hypercapnia has been associated with absence, or less cerebral edema, we considered additional factors to explain cerebral edema and intracranial hypertension causes. Thus, intrathoracic pressures due to patient's efforts by forcibly exhaling, or during mechanical ventilation, would further increase intracranial pressure by limiting cerebral venous drainage. This case emphasizes the fact that patients with acute severe asthma who have developed profoundly hypercarbic without hypoxia before or during mechanical ventilation, may have raised critical intracranial pressure.- - - - - - - - - - ranking = 1keywords = pressure (Clic here for more details about this article) |
2/5. Ocular jellyfish stings.BACKGROUND: Corneal stings from the sea nettle (Chrysaora quinquecirrha) indigenous to the Chesapeake Bay are usually painful but self-limited injuries, with resolution in 24 to 48 hours. methods: Five patients who developed unusually severe and prolonged iritis and intraocular pressure elevation after receiving corneal sea nettle stings were followed for 2 to 4 years. RESULTS: Decreased visual acuity, iritis, and increased intraocular pressure (32 to 48 mmHg) were noted in all cases. iritis responded to topical corticosteroids and resolved within 8 weeks. Elevated intraocular pressure responded to topical beta blockers and oral carbonic anhydrase inhibitors. mydriasis (4 of 5 cases), decreased accommodation (2 of 5 cases), peripheral anterior synechiae (2 of 5 cases), and iris transillumination defects (3 of 5 cases) also were noted. mydriasis and decreased accommodation persisted for 5 months in 1 case and for more than 2 years in another. One patient has chronic unilateral glaucoma. visual acuity returned to normal in all cases. CONCLUSIONS: The precise relationship between sea nettle venom and the observed clinical responses is not known. Corneal jellyfish stings usually produce a brief and self-limited reaction, but they do have the potential for long-term sequelae.- - - - - - - - - - ranking = 1keywords = pressure (Clic here for more details about this article) |
3/5. Fixed, dilated pupil after phakic intraocular lens implantation.A 26-year-old man with degenerative high myopia had bilateral anterior chamber phakic intraocular lens (IOL) implantation under general anesthesia. The preoperative slitlamp examination was normal. No mydriatic drops were used before, during, or after the procedure. Postoperatively, the intraocular pressure (IOP) in the right globe increased to 60 mm Hg. After the IOP was controlled, the pupil became fixed and dilated. iris fluorescein angiography was obtained and delayed filling of the iris capillary plexus with large areas of no perfusion was observed in the right eye. Based on these findings, a diagnosis of Urrets-Zavalia syndrome was made. To our knowledge, this is the first report of Urrets-Zavalia syndrome after phakic IOL implantation.- - - - - - - - - - ranking = 0.33333333333333keywords = pressure (Clic here for more details about this article) |
4/5. Cataractous changes due to posterior chamber flattening with a posterior chamber phakic intraocular lens secondary to the administration of pilocarpine.OBJECTIVE: To present the first reported case of cataract formation as a consequence of instillation of pilocarpine in an eye with a posterior chamber phakic intraocular lens (IOL). DESIGN: Interventional case report. INTERVENTION: A 46-year-old man received a hyperopic implantable collamer lens (ICL) bilaterally. MAIN OUTCOME MEASURES: Determination of best-corrected visual acuity (BCVA); contrast sensitivity testing with and without glare; and intraocular pressure (IOP), specular endothelial cell, and slit-lamp examinations were performed serially. In addition, the distance between the ICL and crystalline lens was measured with optical coherence tomography. RESULTS: Both eyes underwent uneventful ICL implantation for the correction of a manifest spherical equivalent of 7 diopters (D) in the right eye and 7.1 D in the left eye. The left eye was followed for 2 years without developing complications. The right eye, however, showed on the first postoperative day a fleckenlike opacification on the anterior pole of the crystalline lens after instillation on the operative day of 2% pilocarpine in an attempt to accelerate recovery from unwanted pupil dilation causing patient complaints of glare disability after surgery. Optical coherence tomography demonstrated complete contact of the ICL with the natural lens 24 hours postoperatively. Serial IOP measurements were always within the normal limits. The instillation of 1% cyclopentolate resulted in an increase in the ICL vault that measured 132 mum 24 hours later. Three days after the completion of a 3-day course of topical 1% cyclopentolate, the opacification was less dense and demarcated, and a 124-mum vault was measured. Three months postoperatively, the cataract was associated with a 3-line loss of BCVA and considerable degradation of the contrast sensitivity, especially at higher spatial frequencies and with a glare source, and corneal endothelial cell changes were within normal limits. One year after ICL implantation, the right eye had to undergo phacoemulsification and IOL implantation, which were uneventful. CONCLUSIONS: Posterior chamber flattening with resulting crystalline lens opacification can occur immediately after the instillation of pilocarpine in an eye with a hyperopic ICL. Therefore, caution should be taken with the administration of cholinergic agonists such as pilocarpine in patients with phakic IOLs, at least if they are hyperopic ICLs.- - - - - - - - - - ranking = 0.33333333333333keywords = pressure (Clic here for more details about this article) |
5/5. iris ischaemia following penetrating keratoplasty for keratoconus (Urrets-Zavalia syndrome)A fixed and dilated pupil is an uncommon postoperative complication after penetrating keratoplasty (PK) for keratoconus. Although the clinical features have been well described, the precise aetiology is uncertain. We performed anterior segment fluorescein angiography in the early postoperative period on three patients who developed fixed, dilated pupils after apparently uncomplicated surgery. All of the eyes had severe iris ischaemia. A possible role for a postoperative rise in intraocular pressure in the aetiology of this syndrome is discussed.- - - - - - - - - - ranking = 0.33333333333333keywords = pressure (Clic here for more details about this article) |