Movement disorder emergencies in the elderly: Recognizing and treating an often-iatrogenic problem
ABSTRACTMovement disorder emergencies in the elderly—such as rigidity, dystonia, hyperkinetic movements, and psychiatric disturbances—are challenging to manage. Many cases are iatrogenic. In theory, some cases could be avoided by anticipating them and by avoiding polypharmacy and potentially dangerous drug interactions.
KEY POINTS
- Supportive measures must be taken immediately to maintain the functions of vital organs.
- Serotonin syndrome, which can cause rigidity or stiffness, can be prevented by avoiding multidrug regimens.
- Withdrawing or decreasing the dose of dopaminergic drugs in patients with Parkinson disease can cause parkinsonism-hyperpyrexia syndrome, a condition similar to neuroleptic malignant syndrome.
- Metoclopramide (Reglan) accounts for nearly one-third of all drug-induced movement disorders. The entire spectrum of drug-induced movement disorders, ranging from subtle to life-threatening, can ensue from its use.
- Complications of Parkinson disease include hallucinations, dementia, depression, psychosis, and sleep disorders.
Neuroleptic malignant syndrome
This syndrome is an infrequent but potentially lethal complication associated with therapy with antipsychotic drugs such as haloperidol (Haldol) and lithium (Eskalith) and with other medications with dopamine type-2 receptor antagonist activity such as metoclopramide (Reglan) and prochlorperazine (Compazine). It has become rare since the introduction of atypical antipsychotics and now occurs in 0.2% of patients receiving atypical antipsychotics.7 Its pathogenesis is not fully understood.
This syndrome occurs mainly in young or middle-aged patients receiving doses of neuroleptics within the usual therapeutic range, but it also appears to occur in elderly patients who receive higher doses.8 Although most cases develop in the first 2 weeks of treatment, it can develop at any time during therapy.
Signs and symptoms. Four features characterize neuroleptic malignant syndrome9:
- Muscle rigidity—generalized (“lead-pipe”) muscular rigidity is accompanied by bradykinesia or akinesia.
- Autonomic dysregulation, with tachycardia, tachypnea, alterations in blood pressure, excessive sweating, and incontinence.
- Hyperthermia—fever can begin hours to days after initiating or increasing the dose of a dopamine antagonist.
- Altered sensorium, ranging from confusion to disorientation and coma.
Symptoms of neuroleptic malignant syndrome typically evolve over several days, in contrast to the rapid onset of the serotonin syndrome. Knowing the precipitating drug also helps distinguish the syndromes: dopamine antagonists produce bradykinesia, whereas serotonin agonists produce hyperkinesia.5
Laboratory abnormalities include elevated serum creatine kinase concentrations and white blood cell counts. Renal function should be assessed when renal failure and rhabdomyolysis are suspected.
Treatment involves stopping the causative medication, cooling the patient, and supporting vital functions.
In mild cases (eg, low-grade fever) benzodiazepines such as lorazepam (Ativan) can stabilize the condition. In moderate cases (eg, more significant rigidity), dopaminergic agonists such as bromocriptine (Parlodel) can be given, although there is no strong clinical evidence for their use. Bromocriptine is usually started at 2.5 mg three times a day and gradually increased in dose if tolerated.
In severe cases, muscle rigidity can be reduced with dantrolene (Dantrium), a muscle relaxant. Dantrolene is started at 1 mg/kg intravenously every 6 hours and gradually increased up to 10 mg/kg total per day.
Some patients remain rigid and febrile up to 4 weeks after the causative agent has been withdrawn. Therefore, these treatments can be continued for a few weeks. After the patient has recovered fully, if it is necessary to resume antipsychotic therapy, an atypical antipsychotic such as quetiapine (Seroquel) can be started after 2 weeks.8
Comment. Although uncommon, neuroleptic malignant syndrome is the most serious adverse effect of neuroleptic drugs, and it is potentially fatal. When neuroleptic malignant syndrome is suspected, treatment should be prompt, and the neuroleptic medication should be immediately stopped.
Parkinsonism-hyperpyrexia syndrome
Withdrawing or decreasing the dose of dopaminergic medications in patients with Parkinson disease can cause parkinsonism-hyperpyrexia syndrome, a condition that is similar to neuroleptic malignant syndrome. It can also arise after sudden withdrawal of amantadine (Symmetrel) or anticholinergics. In view of this concern, adjustments to antiparkinson drugs may need to be more gradual in some elderly patients.
Patients present with fever, rigidity, and autonomic instability and are at risk of aspiration pneumonia.
Treatment includes resuming dopaminergic therapy and giving supportive care.
Apomorphine (Apokyn), a dopaminergic agonist, was used in a 71-year-old female parkinsonian patient who developed parkinsonism-hyperpyrexia syndrome after abrupt reduction of chronic levodopa treatment.10 The symptoms resolved within 24 hours of the addition of apomorphine to her previous levodopa therapy. If the patient is taking apomorphine for the first time, the injections should be given in low doses, 0.2 mL subcutaneously. Apomorphine can induce vomiting, and if this occurs an antiemetic such as trimethobenzamide (Tigan) should be given before subsequent injections. In the elderly, caution is advised as apomorphine may cause severe orthostasis.
Methylprednisolone (Solu-Medrol) pulse therapy has been shown to shorten the duration of this syndrome in a randomized, controlled study.11
Akinetic syndrome after failure of deep brain stimulator
Deep brain stimulation involves surgical placement of a pacemaker with electrodes in specific areas of the brain. It is used to control Parkinson disease, tremor, and, less commonly, dystonia, and a number of other uses are under investigation. Continuous electrical stimulation of different nuclei in the brain has been shown to alleviate some symptoms of Parkinson disease (eg, rigidity) and to enable some patients to decrease the dose of their antiparkinson medications.
Several cases have been reported of sudden, unexpected reappearance of freezing, gait disturbance, or severe akinesia in Parkinson disease patients whose stimulators had been turned off inadvertently (eg, by a magnet in a dicating machine that was placed too close to the stimulator) and who presented to an emergency room.12
Treatment is easy if this diagnosis is considered. Checking the neurostimulator and switching it to “on” are all that is needed. Since patients and their caregivers are trained how to check and turn on the stimulator, the role of the geriatrician is simply to remind the caregiver of this possibility.
FDA warning. The US Food and Drug Administration has issued a warning against use of shortwave or microwave diathermy for patients with deep brain stimulation or other implanted leads (www.fda.gov/cdrh/safety/121902.html), stating: “There are three types of diathermy equipment used by physicians, dentists, physical therapists, chiropractors, sports therapists, and others: radio frequency (shortwave) diathermy, microwave diathermy, and ultrasound diathermy. Shortwave and microwave diathermy, in both heating and nonheating modes, can result in serious injury or death to patients with implanted devices with leads. This kind of interaction is not expected with ultrasound diathermy. Electrocautery devices are not included in this notification.” If a patient has an implanted deep brain stimulator, magnetic resonance imaging should be done only if absolutely needed and then only if the guidelines are followed.
