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Cataplexy

A sudden, temporary period of muscle weakness in fully-conscious people is called cataplexy. It is one of a series of symptoms found in narcolepsy and it is the primary symptom of nearly three-quarters of the people affected by it. Cataplexy in the absence of narcolepsy is rare. Most often cataplexy is triggered by emotions such as laughing, crying, surprise, fear, etc, and even intense exercise. The cause is believed to be an autoimmune destruction of the neurotransmitter hypocretin in the brain that regulates wakefulness [1].


Presentation

Usually cataplexy presents first in teens and young adults with two peaks at 15 and 35 years of age, however it can be diagnosed in very young or older people, including those past the age of forty. Most commonly it presents with sagging jaw and head plus drooping shoulders. More severe cases often show transient weakness at the knees. Slurred speech may be present. One syndrome involves facial muscles exclusively [5].

Cataplexy occurs most frequently at times of stress, either emotional or when tired and deprived of sleep. In general, the severity of symptoms decreases with age but significant emotional upset, eg. loss of a spouse, can bring about severe attacks again. Most attacks last less than two minutes, a few last up to five minutes but rarely do they last longer than five minutes. Status cataplecticus occurs when repeated attacks recur rapidly, the "limp man syndrome". This is extremely disabling for the individual but is very rare.

Falling
  • Others experience sleep paralysis and are unable to move or speak right before falling asleep or right after waking up.[livestrong.com]
  • Sleep paralysis: a person temporarily can’t move any part of the body upon waking or when falling asleep. Hallucinations: hearing, seeing or feeling things that aren’t there; often happens when falling asleep or waking up.[mydr.com.au]
  • The persons who suffer from this condition experience fatigue and may fall asleep at inappropriate times during the day.[icd9data.com]
  • Some possible symptoms of cataplexy episodes include: drooping eyelids jaw dropping head falling to the side due to neck muscle weakness whole body falling to the ground various muscles around your body twitching without an obvious cause Cataplexy is[healthline.com]
  • Attacks of generalized cataplexy produce complete atonic, areflexic partial or complete paralysis of striated muscles commonly involving the leg muscles resulting in collapse of the knees and falling while milder forms often termed partial cataplexy may[ncbi.nlm.nih.gov]
Turkish
  • Murat Erdem, Oguzhan Oz, Adem Balikci, Mehmet Yucel, Mustafa Alper, Hakan Akgun and Fuat Ozgen, Demographic, clinical, and polysomnographic features in patients with narcolepsy: an experience of 181 patients with narcolepsy from a Turkish sleep center[doi.org]
Malingering
  • These cases represent a diverse set of medical disorders including bradycardia, migraine, delayed sleep phase syndrome, conversion disorder, malingering and a chronic psychotic disorder.[ncbi.nlm.nih.gov]
Asymptomatic
  • She underwent a 99mTc-ethylcysteinate dimer brain SPECT during an episode of cataplexy; this image was compared with her brain SPECT during an intervening asymptomatic period.[ncbi.nlm.nih.gov]
Drop Attacks
  • His recently developed "drop attacks" on laughter were recognized as cataplexy and led to the diagnosis of Niemann-Pick type C disease. With biochemical studies this diagnosis, a lysosomal storage disease, was confirmed.[ncbi.nlm.nih.gov]
  • A 9-year-old boy was admitted for assessments of frequent "drop attacks" while laughing. The filipin fluorescence tests of cultured skin fibroblasts revealed massive accumulation of unesterified cholesterol, confirming the diagnosis of NPC disease.[ncbi.nlm.nih.gov]
  • Cataplexy mimics include syncope, epilepsy, hyperekplexia, drop attacks and pseudocataplexy. They can be differentiated from cataplexy using thorough history taking, supplemented with (home)video recordings whenever possible.[ncbi.nlm.nih.gov]
  • Cataplexy - may mimic drop attacks, syncope, seizures/epilepsy, transient ischaemic attack, periodic paralysis (channelopathies), psychiatric disorder, or cataplectic-like episodes (the latter can occur in healthy people).[patient.info]
Areflexia
  • Examination during a catapletic episode was significant for areflexia and paralysis.[ncbi.nlm.nih.gov]
  • Cataplexy, transient episodes of bilateral muscle weakness with areflexia provoked by emotions, is a state highly specific to narcolepsy. Cataplexy is diagnosed based on clinical interview.[ncbi.nlm.nih.gov]
Tonic-Clonic Seizure
  • One boy also had generalized tonic-clonic seizures. Previous testing revealed that all three have complete ND gene deletions.[ncbi.nlm.nih.gov]
Myokymia
  • Mutations in the KCNA1 gene are known to cause episodic ataxia/myokymia syndrome type 1 (EA1).[ncbi.nlm.nih.gov]
Neurologic Manifestation
  • Abstract Niemann-Pick disease type C (NP-C) is a rare and progressive autosomal recessive disease leading to disabling neurological manifestation and premature death.[ncbi.nlm.nih.gov]

Workup

There is often considerable delay between the onset of catalepsy and a specific diagnosis because of the lack of specific diagnostic tests.

A history of cataplexy in patients with EDS suggests a diagnosis of narcolepsy. In such patients, nocturnal polysomnography followed by multiple sleep latency testing can be confirmatory under the following conditions:

  • Sleep-onset random eye movement (REM) episodes occur during at least 2 out of 5 daytime ‘naps’ or one occurs during a daytime ‘nap’ plus one during the preceding nocturnal polysomnogram [6]
  • Average sleep latency (time to fall asleep) is ≤ 8 minutes
  • No other diagnostic abnormalities are identified on nocturnal polysomnography

The maintenance of wakefulness test does not help with diagnosis but does help monitor treatment efficacy [7]. Tests for other disorders that can cause cataplexy are usually indicated by the clinical history and physical examination. These include:

  • Brain imaging 
  • Blood and urine tests
White Matter Lesions
  • MRI revealed diffuse white-matter lesions involving the medial medulla, pons, and subcortical white matter; protriptyline provided symptomatic relief.[ncbi.nlm.nih.gov]

Treatment

Hypnosis and other techniques of energy medicine, eg. Reiki, have been used with some success. Medical treatment targets cholinergic and noradrenergic neurotransmitter systems. Widely used tricyclic antidepressants (eg. clomipramine, imipramine, orprotriptyline and venlafaxine) inhibit the reuptake of norepinephrine and serotonin at nerve endings. However their potential adverse side-effects have led to their replacement by selective serotonin reuptake inhibitors (SSRIs), eg. fluoxetine, paroxetine, sertraline and citalopram. Serotonin reuptake inhibitors (SSRIs) can be used by all ages of patient with fewer side effects [8].

However both tricyclic antidepressants and SSRIs may cause REM behaviour disorder (RBD) with disturbance of normal REM sleep. They decrease the REM stage of sleep and its associated muscle atonia. As a result, patients may act out their dreams and cause harm to themselves or others.

Sodium oxybate (eg. xyrem) is being used for the treatment of cataplexy, although its mechanism is unknown [9]. Hypocretin gene therapy and hypocretin cell transplantation are emerging for severe syndromes [9].

Prognosis

Almost all cases are transient and, apart from the few cases of secondary catalepsy, the severity of symptoms reduces over time, especially when patients adapt their behavior [10].

Etiology

Within the brain, the hypothalamus regulates basic functions of hormone release, emotional expression and sleep. Patients with symptoms of cataplexy have reduced levels of hypocretin (also called orexin). Hypocretin, regulated by the hypothalamus, is critical in controlling sleep and levels of wakefulness; it also reflects reduced levels of histamine and epinephrine, chemicals that promote wakefulness, arousal and alertness.

Epidemiology

The associated syndrome narcolepsy is known to be strongly associated with certain human leukocyte antigen (HLA) haplotypes. The offspring of such patients have a 40-fold increased likelihood of developing the condition. This suggests a probable genetic cause to the syndrome but, since occurrence in twins is low (25%), this suggests that environmental factors play an important part in triggering the disorder [3] [4].

Sex distribution
Age distribution

Pathophysiology

It has been observed that the level of the neuropeptide hypocretin-1 is reduced in the cerebrospinal fluid of both narcoleptic animals and humans. This suggests that there may be an HLA-associated autoimmune destruction of hypocretin-containing neurons in the hypothalamus.

Sudden, short bouts of excessive daytime sleepiness (EDS) and hypersomnia are commonly seen with acute systemic disorders such as influenza and encephalitis. A range of underlying disease states may also induce cataplexy, EDS and/or hypersomnia:

Cataplexy can also be the result of ischaemic attacks, head injury and multiple sclerosisSecondary cataplexy is caused by space-occupying lesions in the hypothalamus, usually the lateral or posterior lobes, that cause the level of hypocretin to fall. Lesions in the brain or brainstem are uncommon but could include arterio-venous abnormalities or neoplasia. Possible neoplasias include subependynoma, glioma, glioblastoma and astrocytoma. Rarely the syndrome can be the result of paraneoplastic syndromes (the indirect effect of neoplasias).

Iatrogenic cataplexy may also occur, transiently or permanently, due to lesions in the hypothalamus after surgery. The specific lesions or generalized disease or syndromes discussed above disrupt the hypocretin control in the hypothalamus in different ways.

Prevention

It is recognised that many patients learn to avoid the emotions and situations which will trigger their attacks.

Summary

The muscular weakness of cataplexy can vary from slight loosening of facial muscles through to complete muscle paralysis of the whole body to the extent that the patients cannot maintain their posture. Most attacks are short and last between several seconds and a few minutes. The most frequent signs are the jaw dropping and neck weakness but weakness at the knees can be seen, alone or in conjunction with these signs. Slurred speech and impaired vision (eg. inability to focus or double vision) may be identified but hearing and alertness usually remain normal. Patients learn to recognize the slow development of a cataplectic attack, so serious injury from severe attacks is unlikely. Cataplexy attacks are self-limiting and generally resolve without the need for any medical intervention [2].

Patient Information

Definition: Cataplexy is definded as a sudden, temporary episode of muscle weakness in fully-conscious people.

Cause: An autoimmune disease in a neurotransmitter, hypocretin, in the brain that regulates wakefulness is destroyed in most of the cases.

Symptoms: Attacks of muscle weakness that can vary between loosening of facial muscles through to complete muscle paralysis and collapse. Usually they last less than two minutes.

Diagnosis: Clinical signs are usually diagnostic but brain scans may be indicated to rule out underlying causes when the condition is deteriorating.

Treatment: Medical treatment is not usually necessary. Some success is claimed by hypnosis and other energy medicines. Effective drugs include tricyclic antidepressants and newer drugs such as the selective serotonin reuptake inhibitors (SSRIs).

Prevention: Avoid the circumstances that seem to stimulate your own attacks and avoid over-tiredness. Most patients find that the severity of symptoms reduce over several years.

References

Article

  1. Rogers AE, Aldrich MS, Lin X. A comparison of three different sleep schedules for reducing daytime sleepiness in narcolepsy. Sleep. Jun 15 2001;24(4):385-91. 
  2. American Academy of Sleep Medicine. International Classification of Sleep Disorders,. 2nd ed. Darien, IL: American Academy of Sleep Medicine.; 2005.
  3. Longstreth WT Jr, Koepsell TD, Ton TG, et al. The epidemiology of narcolepsy. Sleep 2007; 30:13.
  4. Ohayon MM, Priest RG, Zulley J, et al. Prevalence of narcolepsy symptomatology and diagnosis in the European general population. Neurology 2002; 58:1826.
  5. Burgess CR, Scammell TE. Narcolepsy: neural mechanisms of sleepiness and cataplexy. J Neurosci. Sep 5 2012;32(36):12305-11.
  6. Abad VC, Guilleminault C. Review of rapid eye movement behavior sleep disorders. Curr Neurol Neurosci Rep. Mar 2004;4(2):157-63.
  7. Mignot E, Lammers GJ, Ripley B, Okun M, Nevsimalova S, Overeem S, et al. The role of cerebrospinal fluid hypocretin measurement in the diagnosis of narcolepsy and other hypersomnias. Arch Neurol. Oct 2002;59(10):1553-62
  8. Dauvilliers Y, Arnulf I, Mignot E. Narcolepsy with cataplexy. Lancet. Feb 10 2007;369(9560):499-511.
  9. Lockrane B, Bhatia P, Gore R. Successful treatment of narcolepsy and cataplexy: A review. Can Respir J. May-Jun 2005;12(4):225-7
  10. Dauvilliers Y, Arnulf I, Mignot E. Narcolepsy with cataplexy. Lancet. Feb 10 2007;369(9560):499-511.

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Last updated: 2019-07-11 22:38