Encephalopathy induced hyperammonemic

In two other cases the addition of topiramate was thought to have precipitated valproate-induced hyperammonemic encephalopathy (1172). Recovery occurred after withdrawal of valproate or topiramate. The authors suggested that topiramate may have contributed to the hyperammonemia by inhibiting carbonic anhydrase and cerebral glutamine synthetase. 

Valproate-induced hyperammonemic encephalopathy has been reviewed (1177). Proton magnetic resonance spectroscopy was performed in a patient with valproate-induced hyperammonemic encephalopathy there was a significant fall in the choline and myoinositol resonances and an increase in glutamine in the hyperintense basal ganglia lesions (1178). A similar pattern has been observed in other hyperammonemic encephalopathies, such as hepatic encephalopathy. In another study in seven patients with valproate-related hyperammonemia serum or cerebrospinal fluid glutamine concentrations were initially raised in most patients, sometimes in the absence of hyperammonemia (1179). 

It is difficult to establish a relation between valproate encephalopathy and increased serum ammonium concentrations. Valproate-induced hyperammonemic encephalopathy has been reported in several single case reports, but still it is difficult to ascertain whether hyperammonemia or valproic acid is the cause of the encephalopathy. In one case valproate was used in combination with lithium, which in itself could have caused encephalopathy by displacement of protein binding or other mechanisms, regardless of hyperammonemia (1181). In a second case it was also impossible to evaluate the effect of hyperammonemia on the level of consciousness, since it involved a woman who took valproic acid (30 g) in addition to... 

Lokrantz CM. Eriksson B, Rosen I, Asztely F. Hyperammonemic encephalopathy induced by a combination of valproate and pivmecilhnam Acta Neurol Scand 2004 109 297-301. 

Kifune A, Kubota F, Shibata N, Akata T, Kikuchi S. Valproic acid-induced hyperammonemic encephalopathy with triphasic waves. Epilepsia 2000 41(7) 909-12. 

Valproate-induced hyperammonemic encephalopathy in the presence of topiramate. Neurology 2000 54(l) 230-2. 

Verrotti A, Trotta D, Morgese G, Chiarelli F. Valproate-induced hyperammonemic encephalopathy. Metab Brain Dis 2002 17(4) 367-73. 

Murphy JV. Valproate-induced hyperammonemic encephalopathy. Epilepsia 2003 44 268. 

Yehya N, Saldarini CT, Koski ME, Davanzo P. Valproate-induced hyperammonemic encephalopathy. J Am Acad Child Adolesc Psychiatry 2004 43(8) 926-7. 

Duval L, Hautecoeur P, Mahieu M. Encephalopathie hyper-ammoniemique apres prise de cimetidine. [Cimetidine-induced hyperammonemic encephalopathy.) Presse Med 1999 28(ll) 582-3. 

A 24-year-old man with demyelinating disease had fulminant progression of the disease after he experienced valproate-induced hyperammonemic encephalopathy (120). 

Valproic add, a common anticonvulsant, can accumulate and induce a hyperammonemic encephalopathy, presenting as acutely impaired consciousness, focal neurologic symptoms, and increased seizure frequency. Moreover, valproate-induced hyperammonemic encephalopathy can occur more readily in the child (or adult) with carnitine deficiency or with congenital urea cycle enzymatic defects. In fact, the occult presence of a urea cycle enzymatic defect is occasionally uncovered by the development of valproate-induced encephalopathy an occult enzyme deficiency can even make its first presentation, in the absence of valproate, in the generically stressed critical care patient, young or old (Verrotti et al., 2002 Thakur et al., 2006 Summar et al., 2005). 

Segura-Bruna, N., et al.2006. Valproate-induced hyperammonemic encephalopathy. Acta Neurol Scand, 114(1) pp. 1-7... 

Several cases of valproate-induced hyperammonemic encephalopathy in different clinical conditions have been described [319 320 J, and another case has been described after 18 years of treatment with the drug in a 38-year-old Chinese woman [321 ]. 

The efficacy of intravenous carnitine and glucose -I- thiamine in valproate-induced hyperammonemic encephalopathy has been reported in a further case [355 ]. 

Young L, Coffey BJ. Bipolar disorder and valproate-induced hyperammonemic encephalopathy in an adolescent with diabetes. J Child Adolesc Psychopharmacol 2010 20(5) 449-52. 

Bphmer T, Bpen A, Hpymork SC. Valproate-induced hyperammonemic encephalopathy, rapidly improved by i.v. carnitine and glucose/thiamine. Scand J Gastroenterol 2010 45(6) 762-3. 

Drug-drug interactions Lamotrigine Polypharmacy with enzyme inducers is an important susceptibility factor for valproate encephalopathy. Valproic acid-induced hyperammonemic encephalopathy developed exclusively during concomitant treatment with lamotrigine + valproate in a psychiatric setting [174" ]. 

Valproic acid-induced hyperammonemic encephalopathy is characterized by confusion and possible exacerbation of an... 

Nervous system Encephalopathy There have been several further reports of valproate-induced hyperammonemic encephalopathy [350, 351, 352", 353 ]. In one case it was associated with central pontine mye-linolysis and coma in a patient with Sjogren s syndrome who had taken long-term valproic acid for a psychotic disorder [354 ]. 

Fan CC, Huang MC, Liu HC. Lamotrigine might potentiate valproic acid-induced hyperammonemic encephalopathy. Prog Neuropsychopharmacol Biol Psychiatry 2008 32(7) 1747-8. 

Deutsch SI, Burket JA, Rosse RB. Valproate-induced hyperammonemic encephalopathy and normal liver functions possible synergism with topiramate. Clin Neuropharmacol 2009 32(6) 350-2. 

Dealberto MJ, Sarazin FF. Valproate-induced hyperammonemic encephalopathy without cognitive sequelae a case report in the psychiatric setting. J Neuropsychiatry Clin Neurosci 2008 20(3) 369-71. 

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