Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027066 (myoclonus)
 4,275 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Clozapine is mainly metabolized by the cytochrome P450 1A2 (CYP1A2), which may be inhibited by serious respiratory infections. This case report supports that a serious respiratory infection may increase clozapine levels and contribute to side effects. Plasma clozapine and norclozapine levels were monitored 17 times during 1 year. The concentration-to-dose ratio (C/D), an index of metabolic activity, was obtained by dividing the sum of plasma clozapine and norclozapine concentration (total clozapine concentration) by clozapine dose. The coefficient of variation (CV) of the total clozapine concentrations was calculated at different doses to provide a measure of the noise associated with determining clozapine concentrations in clinical practice. During a respiratory infection, the patient was taking 600 mg/day of clozapine. Clozapine levels were 1245 ng/ml (norclozapine 472 ng/ml), reflecting a decrease in clozapine metabolism by approximately a factor of 2. The high clozapine levels were associated with side effects (myoclonus and increased sedation). The C/D during the infection was 2.9, while the rest of C/Ds ranged between 1.0 and 1.6. CVs before and after the infection, at different doses, were always lower than 20%. When the level during the infection was included to calculate the CV on 600 mg/day, the CV increased to 54%. The theophylline literature, a prior case report and this case all suggest that if a clozapine patient develops a severe respiratory infection with fever, the psychiatrist must pay particular attention to any signs suggestive of major clozapine toxicity associated to a decrease in clozapine metabolism. If any of these signs appear, the psychiatrist may need to consider cutting the clozapine dose in half until the patient has recovered from the infection.
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PMID:Serious respiratory infections can increase clozapine levels and contribute to side effects: a case report. 1449 24

Creutzfeldt-Jakob disease (CJD) is characterised by rapidly progressive dementia, myoclonus, ataxia, visual disturbances and motor dysfunction. Most of the cases are sporadic. Only 10% to 15% are familial, and the most frequent point mutation is E200K. A 53-year-old man presented with subacute progressive bilateral hypoacusis, with tinnitus in the left ear. During the following months, his hypoacusis worsened and he progressively developed bilateral stocking-type paresthaesia and gait instability. An audiometric examination showed bilateral neurosensorial hypoacusis and nerve conduction studies showed a mixed axonal polyneuropathy. A CT scan and MRI of the brain were normal and the electroencephalography (EEG) showed non-specific changes. He died of respiratory infection 10 months after onset of symptoms. Neuropathological examination showed neuronal loss, punctate, synaptic-like deposits of protease-resistant prionic protein (PrP(RES)) in the cerebral and cerebellar cortices and auditory nuclei. This is a rare case of sporadic CJD presenting with hearing loss.
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PMID:Familial Creutzfeldt-Jakob disease with E200K mutation presenting with neurosensorial hypoacusis. 2173 19

A 66-year-old man had a history of an anterior myocardial infarction followed by a successful cardiopulmonary resuscitation and a posthypoxic myoclonus, also known as Lance-Adams syndrome (LAS). Eight years ago, he was admitted to the emergency department with the same myoclonic jerks during an intercurrent respiratory infection. After treatment with clonazepam and resolution of the infection, the myoclonus promptly disappeared. This case report suggests that relapses of successfully treated LAS can occur in vulnerable patients, as it's a chronic form of myoclonus.
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PMID:Late relapse myoclonus in a case of Lance-Adams syndrome. 2429 40