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Title: The Role of a Consultation-Liaison Psychiatrist in Toxicological Insults: Presented at APA

"The Role of a Consultation-Liaison Psychiatrist in Toxicological Insults: Presented at APA"

By Kristina R. Anderson SAN DIEGO, CA -- May 25, 2007 -- Psychiatrists should be on the lookout for patients with adverse reactions to valproic acid, according to a presentation here at the American Psychiatric Association 2007 Annual Meeting (APA). Hyperammonaemic encephalopathy is a rare but serious disorder associated with valproic acid, an antiseizure drug also used for bipolar disorder, migraine, and schizophrenia. Joseph J. Rasimas, MD, consultation-liaison psychiatrist, department of psychiatry and psychology, Mayo Clinic, Rochester, Minnesota, United States, warned, "Toxic states frequently manifest with neuropsychiatric symptoms, and psychiatrists should not forget their medical training and should be on the lookout for a medical cause in patients who show up sick who are on psychotropic polypharmacies." Dr. Rasimas said that the advances in research and in drug treatments for mental illnesses have brought a menu of potential adverse effects and some frank toxicological syndromes that are secondary to the original treatment medication or combinations of medications. Many psychiatrists, he said, do not consider potential toxic side effects in patients. "Not only do prescribers expose patients to risks of adverse effects in medications, but psychiatric patients use medications counter to their therapeutic purposes with higher frequency than any other modality of self harm," Dr. Rasimas wrote in his research poster. In his presentation on May 21[^st, Dr. Rasimas discussed the case of a 36-year-old with treatment-resistant schizoaffective disorder and quiescent hepatitis C who returned to the emergency department in a state of lethargy and confusion less than 3 weeks after being hospitalised for lithium toxicity. Personnel in the ER started the man on sodium divalproex, at a dosage of 1000 mg in the interim to treat hypomania. A nightly dosage ultimately resulted in a serum level of 114 mcg/mL; sodium divalproex is chemically related to valproic acid.

When the patient was admitted to the hospital, his AST and ALT were normal at levels of 17 U/L and 44 U/L, respectively, while ammonia was elevated at 66 mcg N/dL. Serum lithium was 1.2 mmol/L.

Dr. Rasimas said he was asked to consult on the case, at which time he determined that the patient's dose of sodium divalproex should be immediately discontinued, suspecting a case of hepatotoxicity. The patient's other psychotropic medications, including lithium, were then resumed. Lactulose and supportive care were given. Ammonia peaked at 111 mcg N/dl within 36 hours of presentation while AST and ALT never exceeded 38 U/L and 81 U/L, respectively.

The symptoms of delirium resolved slowly during the 96 hours following the discontinuation of divalproex sodium.

Polypharmacy is a recognised risk factor in the development of toxicological adverse reactions. The key to good outcomes, especially in cases of valproate-induced hyperammonaemic encephalopathy, is early recognition and cessation of the offending treatment agent, Dr. Rasimas said.

He suggests to psychiatrists, "Keep your toxicology hat on."

[Presentation title: The C/L Psychiatrist as Toxicologist: An Illustrative Case. Abstract N171]

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