A 28-year-old graduate student complains of the recent onset of episodes of sudden jaw weakness following heightened emotions such as laughter or anger. She is very distressed, and has been avoiding emotionally laden situations to prevent the occurrence of these spells. Her advisor recently revealed that colleagues had complained that she appeared “drunk,” as she had slurred speech in class following an argument.
The most likely explanation for these episodes is:A. Transient ischemic attack
C. Atonic seizure
Answer: B. Cataplexy
Cataplexy is a brief (seconds to minutes) and sudden bilateral loss of muscle tone, during which consciousness is maintained; it is precipitated by emotion (laughter or joking). It occurs almost exclusively in the context of narcolepsy. It is thought to represent REM-associated muscle atonia occurs that strikes during wakefulness. It may be mild, leading to facial or limb weakness or a feeling general body weakness. Less commonly, it can lead to collapse and falls. Patients are usually aware of their surroundings, even if completely immobilized, and memory for the episodes is presereved afterwards, two features that distinguish these episodes from epilepsy. Muscle control is regained typically after a few seconds or minutes, although lengthy episodes have been described following which patients may fall asleep. During the episodes, if patients are examined, they lack deep tendon reflexes. As noted above, cataplexy typically occurs in the context of narcolepsy, in which case it is always associated with the complaint of excessive daytime sleepiness, and can be associated with sleep paralysis, hypnagogic hallucinations, and disrupted nocturnal sleep.
The treatment of excessive sleepiness in narcolepsy usually involves judicious napping and maintenance of proper sleep hygiene behavior, and pharmacologic agents. Cataplexy is typically managed by REM-suppressant agents, including tricyclic antidepressants (eg, clomipramine and protryptiline), selective serotonin reuptake inhibitors (fluoxetine, fluvoxamine), and selective serotonin/norepinephrine reuptake inhibitors (venlafaxine, atomoxetine).
Atonic seizures (also called drop seizures, akinetic seizures or drop attacks), result in a brief lapse in muscle tone as a result of temporary alterations in brain function, but are typically not induced by heightened emotion. Transient ischemic attacks typically cause loss of function for longer periods of time, and catalepsy, the homonym of cataplexy, is characterized by a fixed and rigid body posture that occurs in the context of Parkinson’s disease, epilepsy, and psychotic conditions. Bruxism is excessive tooth clenching.
1. Cataplexy is the pathognomonic symptom of narcolepsy and is characterized by muscle weakness triggered by emotions including joking, laughter, excitement, anger.
2. Cataplexy is typically brief in duration, mostly bilateral, may affect any voluntary muscles and cause knee/leg buckling, jaw sagging, head drooping, postural collapse.
3. During cataplexy, consciousness is maintained.
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Mitler MM, Nelson S, Hajdukovic R. Narcolepsy. Diagnosis, treatment, and management. Psychiatr Clin North Am. 1987;10:593-606.