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)

Cases of N-acetylcysteine overdose have been reported before. In some cases, these overdoses have led to death if an anaphylactoid reaction was present. A healthy 30-month-old girl allegedly ingested acetaminophen at 418 mg/kg. Because the emergency physician feared the time of ingestion might not be accurate, he decided to start the 20.5-hour intravenous N-acetylcysteine protocol 8 hours after ingestion. He mistakenly prescribed the maximum milliliter-per-kilogram volume of the dextrose 5% diluent for the milliliter-per-kilogram volume of N-acetylcysteine 20% to be administered. Five hours after the error was detected (19.5 hours postingestion), the patient started developing myoclonus on the left side of her body, with left eye deviation. This condition persisted intermittently for 3 hours despite treatment with diazepam, lorazepam, and phenytoin. A first computed tomographic scan result was normal. A few hours later, she sustained shorter recurrences of the myoclonus. At 30 hours after ingestion, she started to have irregular breathing and became unresponsive to pain. A repeated computed tomographic scan showed diffuse cerebral edema. A postmortem examination showed the presence of acute anoxic encephalopathy with marked cerebral edema and the beginning of uncal herniation that confirmed the clinical diagnosis of intracranial hypertension and brain death. A cumulative intravenous dose of 2,450 mg/kg of N -acetylcysteine was associated with status epilepticus, intracranial hypertension, and death in a child.
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PMID:Status epilepticus after a massive intravenous N-acetylcysteine overdose leading to intracranial hypertension and death. 1545 24

Myoclonic movements and pain on injection are common problems during induction of anesthesia with etomidate. We investigated the influence of pretreatment with magnesium and two doses of ketamine on the incidence of etomidate-induced myoclonus and pain. A prospective double-blind study was performed on 100 ASA physical status I-III patients who were randomized into 4 groups according to the pretreatment drug: ketamine 0.2 mg/kg, ketamine 0.5 mg/kg, magnesium sulfate (Mg) 2.48 mmol, or normal saline. Ninety seconds after the pretreatment, anesthesia was induced with etomidate 0.2 mg/kg. Vecuronium 0.1 mg/kg was used as the muscle relaxant. An anesthesiologist, blinded to group allocation, recorded the myoclonic movements, pain, and sedation on a scale between 0-3. Nineteen of the 25 patients receiving Mg (76%) did not have myoclonic movements after the administration of etomidate, whereas 18 patients (72%) in the ketamine 0.5 mg/kg, 16 patients (64%) in the ketamine 0.2 mg/kg, and 18 patients (72%) in the control group experienced myoclonic movements (P < 0.05). We conclude that Mg 2.48 mmol administered 90 s before the induction of anesthesia with etomidate is effective in reducing the severity of etomidate-induced myoclonic muscle movements and that ketamine does not reduce the incidence of myoclonic movements.
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PMID:Magnesium sulfate pretreatment reduces myoclonus after etomidate. 1611 78

Despite skilled palliative care, some dying patients experience distressing symptoms that cannot be adequately relieved. A patient with metastatic breast cancer, receiving high doses of opioids administered to relieve pain, developed myoclonus. After other approaches proved ineffective, palliative sedation was an option of last resort. The doctrine of double effect, the traditional justification for palliative sedation, permits physicians to provide high doses of opioids and sedatives to relieve suffering, provided that the intention is not to cause the patient's death and that certain other conditions are met. Such high doses are permissible even if the risk of hastening death is foreseen. Because intention plays a key role in this doctrine, clinicians must understand and document which actions are consistent with an intention to relieve symptoms rather than to hasten death. The patient or family should agree with plans for palliative sedation. The attending physician needs to explain to them, as well as to the medical and nursing staff, the details of care and the justification for palliative sedation. Because cases involving palliative sedation are emotionally stressful, the patient, family, and health care workers can all benefit from talking about the complex medical, ethical, and emotional issues they raise.
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PMID:Palliative sedation in dying patients: "we turn to it when everything else hasn't worked". 1653 35

Pain is not the most frequent symptom in cancer patients, but it is considered the most serious and threatening symptom. Opioid analgesics are the mainstay for analgesic treatment of cancer patients. Methadone is increasingly being considered as an alternative to morphine and seems to become relatively more potent with increasing exposure to other opioids. "Newer" side effects of opioids have been demonstrated, including cognitive impairment, generalized allodynia/hyperalgesia, myoclonus and hallucinations. When the pain relief effects of oral opioids have been exhausted, other pain management approaches, including spinal delivery of analgesics, may be effective alternatives.
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PMID:[Cancer-related pain]. 1676 93

We report on a patient with segmental rhythmic myoclonus resembling belly dance. This patient developed the myoclonus in temporal and anatomical association with chronic abdominal pain. No structural or metabolic abnormalities were found. EMG recordings suggested the presence of a spinal cord central pattern generator (CPG). We hypothesize that pain-related spinal plasticity might have contributed to the hyperactivity of a spinal CPG, thus leading to the myoclonic jerks in our patient.
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PMID:Belly dancer's myoclonus and chronic abdominal pain: pain-related dysinhibition of a spinal cord central pattern generator? 1704 97

Little information is available about the incidence, prevalence, or severity of morphine side effects during repeated individualized dosing for chronic cancer pain, although it has been widely used in this way for more than 30 years. The authors' aim was to describe the prevalence of symptoms possibly attributable to morphine side effects in a convenience sample of patients with pain due to advanced cancer. They used a prospective survey of inpatients and outpatients on regularly dosed morphine, with a questionnaire administered weekly for 4 weeks. Forty-two of 56 eligible patients completed at least the first questionnaire, with 30 completing all 4. Dry mouth was the most common symptom reported (point prevalence, 95%); this was often moderate to severe in intensity (57%) and was the most persistent symptom (period prevalence, 20%). Sedation and constipation were frequent (point prevalence, 88%) and was often moderate or severe at some point (55% and 62%, respectively) but had low period prevalence. Nausea was reported by less than half the patients. Myoclonus was common (point prevalence, 83%) but was usually mild and not persistent. Total daily morphine dose had little impact on side-effect patterns. Constipation, dysphoria, myoclonus, nausea, and sedation were more likely to be severe following dose increases. In conclusion, although constipation, nausea, and sedation are well described as side effects of morphine administration, others such as dry mouth and myoclonus appear to be underestimated. Validated patient-based measures of opioid side effects are needed.
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PMID:The adverse effects of morphine: a prospective survey of common symptoms during repeated dosing for chronic cancer pain. 1706 Feb 84

Opioids, defined as drugs that stimulate opioid receptors, are primarily used in the treatment of moderate to severe pain. They induce central nervous system (CNS) adverse effects which can be divided into three groups. The first group includes effects that lower the level of consciousness-sedation, drowsiness and sleep disturbance. The second group affects the thinking process and the ability to react-cognitive impairment, psychomotor impairment, delirium, hallucinations, dreams and nightmares. The third group is of the direct toxic effects of opioids on neurons and includes myoclonus (perhaps), hyperalgesia and tolerance. This review addresses the incidence, possible mechanisms, and treatment of each of these groups of opioid-induced adverse effects.
J Pain Palliat Care Pharmacother 2007
PMID:Adverse effects of opioids on the central nervous systems of palliative care patients. 1743 Aug 25

A patient with pain associated with metastatic leiomyosarcoma received escalating doses of opioids. Upon discontinuation of intravenous morphine, transdermal fentanyl was initiated, and after several days, the dose was increased to 200microg/hour for persistent, severe pain. The patient became somnolent, and further dose adjustments and route change were carried out. She then exhibited severe allodynia, myoclonus, and delirium thereafter fentanyl was stopped. All symptoms resolved with discontinuation of fentanyl and subsequent introduction of a weak opioid. Pain was well controlled. Gradually increasing standard doses of fentanyl may lead to severe neurotoxicity, which may respond to opioid discontinuation and/or rotation. Vigilant scrutiny of all possible causes of apparent analgesic failure followed by consideration of opioid reduction and rotation is warranted in cases of neurotoxicity accompanying opioid treatment.
J Pain Symptom Manage 2008 Mar
PMID:Fentanyl-induced neurotoxicity and paradoxic pain. 1822 28

Medications which bind to opioid receptors are increasingly being prescribed for the treatment of multiple and diverse chronic painful conditions. Their use for acute pain or terminal pain is well accepted. Their role in the long-term treatment of chronic noncancer pain is, however, controversial for many reasons. One of the primary reasons is the well-known phenomenon of psychological addiction that can occur with the use of these medications. Abuse and diversion of these medications is a growing problem as the availability of these medications increases and this public health issue confounds their clinical utility. Also, the extent of their efficacy in the treatment of pain when utilized on a chronic basis has not been definitively proven. Lastly, the role of opioids in the treatment of chronic pain is also influenced by the fact that these potent analgesics are associated with a significant number of side effects and complications. It is these phenomena that are the focus of this review. Common side effects of opioid administration include sedation, dizziness, nausea, vomiting, constipation, physical dependence, tolerance, and respiratory depression. Physical dependence and addiction are clinical concerns that may prevent proper prescribing and in turn inadequate pain management. Less common side effects may include delayed gastric emptying, hyperalgesia, immunologic and hormonal dysfunction, muscle rigidity, and myoclonus. The most common side effects of opioid usage are constipation (which has a very high incidence) and nausea. These 2 side effects can be difficult to manage and frequently tolerance to them does not develop; this is especially true for constipation. They may be severe enough to require opioid discontinuation, and contribute to under-dosing and inadequate analgesia. Several clinical trials are underway to identify adjunct therapies that may mitigate these side effects. Switching opioids and/or routes of administration may also provide benefits for patients. Proper patient screening, education, and preemptive treatment of potential side effects may aid in maximizing effectiveness while reducing the severity of side effects and adverse events. Opioids can be considered broad spectrum analgesic agents, affecting a wide number of organ systems and influencing a large number of body functions.
Pain Physician 2008 Mar
PMID:Opioid complications and side effects. 1844 35

Myoclonus is a well-known side effect of anticonvulsant drugs. Pregabalin is one of the newer drugs approved for the treatment of focal epilepsies. Frequently it is also used to treat chronic pain syndromes. We describe a patient who, after receiving his first dose of pregabalin to relieve neuropathic pain, presented with a negative myoclonus. Clinical aspects and electrophysiological data such as polygraphic studies, electroencephalography, and measurement of somatosensory evoked potentials support the cortical origin of negative myoclonus. Our findings reveal that even in patients without a history of seizures, pregabalin can cause a cortical negative myoclonus.
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PMID:Pregabalin-induced cortical negative myoclonus in a patient with neuropathic pain. 1849 17


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