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IN THIS ISSUE:
April 2007

Paliperidone (Invega)
Paliperidone (Invega), recently approved to treat schizophrenia, is similar to risperidone (Risperidone) in efficacy and adverse effects.

Methylphenidate for ADHD in Preschool Children
Low doses of methylphenidate (Ritalin and others) are effective and safe for preschool children with ADHD but may cause more side effects than in older children.

A Case of Wernicke's Encephalopathy
Wernicke's encephalopathy is caused by thiamine deficiency, usually due to alcoholism or malnutrition.

In Brief
Taste Altered in Mood Disorders; Reduced Gray Matter May Predict Schizophrenia; FDA Issues Methadone Alert

Two Ineffective Adjuncts for Mania
Olanzapine (Zyprexa) and topiramate (Topamax) add no therapeutic benefit as adjunctive treatments for bipolar disorder.

Schizophrenia, Substance Abuse, and Violence
Substance abuse increases the risk of violent behavior in people with schizophrenia.

A Case of Wernicke's Encephalopathy

April 2007

First described in the 1880s, Wernicke's encephalopathy is characterized by nystagmus, abducens nerve and conjugate gaze palsies, gait ataxia, and confusion.1 Wernicke's is believed to be caused by thiamine deficiency, and the extraocular paralyses in particular respond rapidly to IV administration of thiamine. Wernicke's encephalopathy is a medical emergency, as neurons are actively dying in the absence of thiamine. Without thiamine, Wernicke's progresses to Korsakoff's psychosis, with its characteristic dense anterograde amnesia and confabulation. This chronic condition is associated with a 17% rate of mortality.1

The thiamine deficiency that underlies Wernicke-Korsakoff syndrome is most typically associated with chronic alcoholism. But nutritional deficiencies can occur in other circumstances. Harrison and others report on a 51-year-old man with chronic schizophrenia whom they diagnosed with Wernicke's encephalopathy.2

The patient was admitted to a hospital because of tonic-clonic seizures. Several months before the admission, he had stopped his antipsychotic medication, and his chronic mental illness deteriorated. He was said to have abused alcohol in the distant past but was reliably reported to have been abstinent for at least several years.

On hospital admission, the patient was confused, disoriented, and agitated, as well as emaciated and disheveled. His range of eye movements was restricted, with limitations bilaterally of vertical and horizontal gaze. Doctors administered thiamine, 100 mg IV, along with multivitamins and phenytoin. His mental state, dyskinesia, rigidity, and ophthalmoplegia improved rapidly. A magnetic resonance imaging (MRI) scan was consistent with a diagnosis of Wernicke's encephalopathy.

Seizures are uncommon with the Wernicke-Korsakoff syndrome. The authors acknowledge that their patient, who was dehydrated and showed severe malnutrition, may have had other brain pathology as well. Nonetheless, the confusion and ophthalmoplegia, and the rapid response to IV thiamine, supports the diagnosis of Wernicke's encephalopathy.

The response of ophthalmoplegia to IV thiamine tends to be rapid. Ataxia may respond a little more slowly. Memory and cognition respond variably, probably related to how long the brain has been thiamine depleted.

This newsletter frequently mentions the health needs of patients with chronic mental illness. Among other risks, they are vulnerable to dehydration and malnutrition, which can include vitamin deficiency. Because they also have a high prevalence of alcohol abuse, the risk of a serious brain impairment such as Wernicke's encephalopathy is magnified. A clinical awareness of Wernicke's can, as in this case, lead to rapid intervention and at least partial improvement.

1Ropper AH, Brown RH: Diseases of the Nervous System due to Nutritional Deficiency, 8th ed. McGraw-Hill, Adams and Victor's Principles of Neurology, 2005, pp. 984-988.

2Harrison RA, Vu T, Hunter AJ: Wernicke's encephalopathy in a patient with schizophrenia. J Gen Intern Med 2006;21:C8-C11.