Valproate-induced hyperammonemia - Uncovering an underlying inherited metabolic disorder: A case report

TY - JOUR

T1 - Valproate-induced hyperammonemia - Uncovering an underlying inherited metabolic disorder

T2 - A case report

AU - Mehta, Shaine

AU - Tayabali, Sarrah

AU - Lachmann, Robin

PY - 2018/5/17

Y1 - 2018/5/17

N2 - Background: Sodium valproate is a commonly used anticonvulsant. It is widely recognized that valproate can cause hyperammonemia, particularly in people with underlying liver disease. Patients with urea cycle disorders are genetically predisposed to this adverse event and can develop severe hyperammonemia if given valproate. This can occur even if liver functions tests and plasma concentration of valproate are normal, highlighting the importance of checking ammonia levels in any patient presenting with encephalopathy. Specific treatment for hyperammonemia must be implemented promptly. Case presentation: A 22-year-old white British man with a history of epilepsy post head trauma presented with subacute encephalopathy 4 weeks after the introduction of sodium valproate. His ammonia levels were not checked until 48 hours into his presentation and were found to be elevated. He initially responded to treatment of his hyperammonemia and the raised levels were attributed to sodium valproate. However, as his ammonia levels continued to rise, further investigation led to a diagnosis of ornithine transcarbamylase deficiency. Conclusions: Ornithine transcarbamylase deficiency is the most common of the urea cycle disorders. This case highlights both the importance of checking ammonia levels early and considering the diagnosis of this X-linked disorder in patients with raised ammonia, as these have implications both for the patient's acute and further management, and for family screening.

AB - Background: Sodium valproate is a commonly used anticonvulsant. It is widely recognized that valproate can cause hyperammonemia, particularly in people with underlying liver disease. Patients with urea cycle disorders are genetically predisposed to this adverse event and can develop severe hyperammonemia if given valproate. This can occur even if liver functions tests and plasma concentration of valproate are normal, highlighting the importance of checking ammonia levels in any patient presenting with encephalopathy. Specific treatment for hyperammonemia must be implemented promptly. Case presentation: A 22-year-old white British man with a history of epilepsy post head trauma presented with subacute encephalopathy 4 weeks after the introduction of sodium valproate. His ammonia levels were not checked until 48 hours into his presentation and were found to be elevated. He initially responded to treatment of his hyperammonemia and the raised levels were attributed to sodium valproate. However, as his ammonia levels continued to rise, further investigation led to a diagnosis of ornithine transcarbamylase deficiency. Conclusions: Ornithine transcarbamylase deficiency is the most common of the urea cycle disorders. This case highlights both the importance of checking ammonia levels early and considering the diagnosis of this X-linked disorder in patients with raised ammonia, as these have implications both for the patient's acute and further management, and for family screening.

KW - Encephalopathy

KW - Liver disease

KW - OTC

KW - Sodium valproate

UR - http://www.scopus.com/inward/record.url?scp=85047178632&partnerID=8YFLogxK

U2 - 10.1186/s13256-018-1666-3

DO - 10.1186/s13256-018-1666-3

M3 - Article

C2 - 29769109

AN - SCOPUS:85047178632

SN - 1752-1947

VL - 12

JO - Journal of medical case reports

JF - Journal of medical case reports

IS - 1

M1 - 134

ER -