Introduction. –
Les auteurs rapportent trois observations de trouble neurologique imputé à un traitement par Zelitrex® (valaciclovir), chez des patients insuffisants rénaux.
Exégèse. –
Les trois ...patients sont deux femmes et un homme âgés de 76 ± 4,6 ans. Ils ont tous présenté un épisode de confusion mentale ayant dans les trois cas entraîné une hospitalisation. Dans deux cas, les patients présentaient une insuffisance rénale chronique et étaient suivis en dialyse péritonéale. Dans le troisième cas, l’insuffisance rénale a été contemporaine de la toxicité neurologique. L’évolution a toujours été favorable à l’arrêt du traitement.
Conclusion. –
Ces observations attirent l’attention sur le risque de toxicité neurologique lié à la prise de valaciclovir, prodrogue de l’aciclovir, pour lequel l’amélioration significative de la biodisponibilité n’est pas toujours prise en compte pour la détermination des posologies recommandées.
Introduction. –
We report three cases of neurotoxicity in patients with renal failure, treated with Zelitrex® (valacyclovir).
Exegesis. –
The patients are two women and a man, aged 76 ± 4.6 years, who presented acute mental confusion during a treatment with valacyclovir. In two cases, the patients previously had altered renal function and were under peritoneal dialysis. In the last case, the patient had simultaneous neurotoxicity and acute renal failure. After the discontinuation of the drug, the outcome was favourable in all cases.
Conclusion. –
Our cases focus attention on the possible neurotoxicity of valacyclovir, which is an amino acid ester prodrug of acyclovir, rapidly and almost completely hydrolysed to acyclovir prior to systemic exposure. The bioavailability of valacyclovir is 54% compared to approximately 20% for oral acyclovir and may account for unexpected overdoses, which may lead to serious neurological toxicity.
Blind deep venous puncture is an invasive procedure with risks of serious complications compromising the availability of veins for future punctures or endangering the patient's life. We designed a ...new hand-held pulsed Doppler probe for coaxial guidance of the puncture needle and a dedicated pulsed Doppler device displaying the depth of the measurement volume. We used this technique prospectively in two independent centers (the nephrology department and the intensive care unit) involving senior as well as junior staff members. Either the non-Doppler or the Doppler method were randomly selected for subclavian vein catheterization in 100 patients and for internal jugular vein catheterization in 30 patients. The success rate on the first attempt was 86.2% for the non-Doppler method versus 96.8% for the Doppler method (p = 0.03). The failure rate of the non-Doppler method used by junior staff members was 9.2%, reduced to 1.5% (p = 0.05) by secondary use of the Doppler method and/or help from a senior staff member (rescue procedure). Pulsed Doppler guidance reduced significantly the failure rate of venous punctures especially when used by seniors or by juniors after a training period.
We describe a 50-year-old man with a severe acquired haemorrhagic syndrome. He had slightly prolonged clotting times using bovine thrombin, human thrombin and reptilase. His plasma contained a ...polyclonal IgG which interfered with the generation of fibrin monomers without inhibiting the aggregation of preformed monomers. The inhibitor delayed thrombin-induced fibrinopeptide A release. The IgG bound to insolubilized synthetic fibrinopeptide A (one binding site per molecule) and, with higher affinity, to fibrinogen (two binding sites per molecule). It did not bind to insolubilized fibrin monomers. The IgG did not impair the catalytic activity of thrombin toward a small synthetic substrate but inhibited the binding of thrombin to fibrinogen without binding to thrombin. The binding of the anti-fibrinopeptide A autoantibody to fibrinogen might have impaired thrombin-induced fibrinogen to fibrin conversion in vivo. This may have favoured the reported haemorrhagic syndrome which was associated with severe chronic renal insufficiency.
In the anaesthetized dog, porcine pancreastatin (98 pmol/min) was infused for 10 min into the pancreaticoduodenal artery either alone or during infusion of glucose. Blood was sampled from the ...pancreaticoduodenal vein. We found that pancreastatin inhibited pancreatic insulin output only under normoglycaemic conditions. Furthermore, pancreastatin significantly stimulated pancreatic glucagon and somatostatin outputs both during normo- and hyperglycaemic conditions. Our results show that pancreastatin has the capability to affect directly the three pancreatic hormone secretions in dogs.
