Dear Editors
We read with interest the manuscript published by Viana et al.11 . Viana CF, Pradella-Hallinan M, Quadros AA, Marin LF, Oliveira AS.
Circadian variation of fatigue in both patients with paralytic poliomyelitis and
post-polio syndrome. Arq Neuropsiquiatr 2013;71:442-445.. These authors observed in a small cohort of paralytic
poliomyelitis (PP) and postpolio syndrome (PPS) patients a significant circadian fatigue
in both forms. The authors also evaluated polysomnographic variables lacking
correlations between PSG data and fatigue. In PP, an acute disease resulting in flaccid
paralysis, it has been shown that polio virus may induce apoptosis and consequently CNS
injury, which leads to paralysis. Therefore during its clinical course an increasing and
progressive fatigue may represent an integral part of motor symptoms, while PPS
circadian impairment of fatigue may be more puzzling. Sleep disorders and particularly
sleep related breathing disorders, restless legs syndrome and periodic limbs movement of
sleep (PLMS) were described in PPS22 . Araujo MA, Silva TM, Moreira GA, Pradella-Hallinan M, Tufik S,
Oliveira AS. Sleep disorders frequency in post-polio syndrome patients caused by
periodic limb movements. Arq Neuropsiquiatr 2010;68:35-38.,33 . Marin LF, Carvalho LB, Prado LB, Quadros AA, Oliveira AS, Prado
GF. Restlesslegs syndrome in post-polio syndrome: a series of 10 patients with
demographic,clinical and laboratorial findings. Parkinsonism Relat Disord
2011;17:563-564..
Small cohorts, single case reports, uncontrolled design, selected samples complaining of
fatigue, sleepiness are critical issues for these reports. An intriguing model and a
probable unifying hypothesis may be represented by restless legs syndrome (RLS). A
circadian fatigue in PPS may be the expression of unrecognized RLS in PPS. The frequency
of RLS and PLMS is higher than general population in several neurological diseases44 . Weinstock LB, Walters AS, Paueksakon P. Restless legs
syndrome-theoretical roles of inflammatory and immune mechanisms. Sleep Med Rev
2012;16:341-354.,55 . Romigi A, Albanese M, Liguori C, Placidi F, Marciani MG and Massa
R. Sleep-Wake Cycle and daytime sleepiness in the myotonic dystrophies. J
Neurodegenerat Dis 2013, doi.org/10.1155/2013/692026
https://doi.org/10.1155/2013/692026...
. The 95% of highly associated RLS conditions are linked
with inflammatory/immune changes. This observation suggested that RLS is mediated or
affected by inflammation as recently demonstrated by elevated C-reactive protein (CRP)
in RLS with severe PLMS44 . Weinstock LB, Walters AS, Paueksakon P. Restless legs
syndrome-theoretical roles of inflammatory and immune mechanisms. Sleep Med Rev
2012;16:341-354.. Similarly in
PPS it is still debated whether the denervation processes are caused by further loss of
motor neurons due to normal aging or active disease processes, involving chronic
inflammatory damage66 . Fordyce CB, Gagne D, Jalili F, et al. Elevated serum inflammatory
markers in post-poliomyelitis syndrome. J Neurol Sci
2008;271:80-86.. These
observations are supported by the increased expression of pro-inflammatory cytokines in
PPS66 . Fordyce CB, Gagne D, Jalili F, et al. Elevated serum inflammatory
markers in post-poliomyelitis syndrome. J Neurol Sci
2008;271:80-86.. The driver of these
inflammatory mechanisms is still unclear. Therefore RLS and PPS may share a common
pro-inflammatory condition. Viana et al.11 . Viana CF, Pradella-Hallinan M, Quadros AA, Marin LF, Oliveira AS.
Circadian variation of fatigue in both patients with paralytic poliomyelitis and
post-polio syndrome. Arq Neuropsiquiatr 2013;71:442-445. found more than one third of PPS patients had PLMS, although no
statistical correlation was found between fatigue and PSG. In addition, as correctly
stated in discussion, authors11 . Viana CF, Pradella-Hallinan M, Quadros AA, Marin LF, Oliveira AS.
Circadian variation of fatigue in both patients with paralytic poliomyelitis and
post-polio syndrome. Arq Neuropsiquiatr 2013;71:442-445. did not
evaluate RLS in their PPS patients.
Although small PPS samples with RLS and/or PLMS do not allow any generalization, the common inflammatory pathways and also a natural propensity to circadian trend of fatigue in PPS, as interestingly demonstrated by Viana et al.11 . Viana CF, Pradella-Hallinan M, Quadros AA, Marin LF, Oliveira AS. Circadian variation of fatigue in both patients with paralytic poliomyelitis and post-polio syndrome. Arq Neuropsiquiatr 2013;71:442-445., may support the association of PPS with RLS. Epidemiological studies with controlled design are needed to explore the real magnitude of RLS in PPS and to evaluate possible common mechanisms involved in the development of RLS.
References:
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1Viana CF, Pradella-Hallinan M, Quadros AA, Marin LF, Oliveira AS. Circadian variation of fatigue in both patients with paralytic poliomyelitis and post-polio syndrome. Arq Neuropsiquiatr 2013;71:442-445.
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2Araujo MA, Silva TM, Moreira GA, Pradella-Hallinan M, Tufik S, Oliveira AS. Sleep disorders frequency in post-polio syndrome patients caused by periodic limb movements. Arq Neuropsiquiatr 2010;68:35-38.
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3Marin LF, Carvalho LB, Prado LB, Quadros AA, Oliveira AS, Prado GF. Restlesslegs syndrome in post-polio syndrome: a series of 10 patients with demographic,clinical and laboratorial findings. Parkinsonism Relat Disord 2011;17:563-564.
-
4Weinstock LB, Walters AS, Paueksakon P. Restless legs syndrome-theoretical roles of inflammatory and immune mechanisms. Sleep Med Rev 2012;16:341-354.
-
5Romigi A, Albanese M, Liguori C, Placidi F, Marciani MG and Massa R. Sleep-Wake Cycle and daytime sleepiness in the myotonic dystrophies. J Neurodegenerat Dis 2013, doi.org/10.1155/2013/692026
» https://doi.org/10.1155/2013/692026 -
6Fordyce CB, Gagne D, Jalili F, et al. Elevated serum inflammatory markers in post-poliomyelitis syndrome. J Neurol Sci 2008;271:80-86.
Publication Dates
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Publication in this collection
June 2014
History
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Received
01 Sept 2013 -
Reviewed
09 Jan 2014 -
Accepted
29 Jan 2014