sábado, 26 de diciembre de 2015
martes, 22 de diciembre de 2015
FIEBRE Y USO DE ANTIPIRÉTICOS EN NIÑOS
Fiebre y uso de
antipiréticos en niños
Pediatrics 2011;127:580-587 .
La fiebre es un signo común manejado
por el pediatra y
otros profesionales de la salud, presentándose en un tercio de las patologías
en niños. Los familiares se preocupan frecuentemente por la necesidad de
mantener una temperatura normal en los niños enfermos.
En 50% de los casos, los padres consideran fiebre a
la temperaturas < 38 °C(100.4°F) y 25% de los cuidadores administrarán algún
antipirético para temperatura menores de 37.8 °C
Hasta 85%
de los padres refieren levantar a su niño para
administrar el antipirético. Desafortunadamente, los padres en 50% de los casos
administran incorrectamente
las dosis de antipiréticos y aproximadamente 15% de
los padres usan dosis supra-terapéuticas de
paracetamol o ibuprofeno. Los cuidadores deben
entender que la dosis depende del peso del paciente y no de la edad o estatura.
Las indicaciones más comunes para prescribir
antipiréticos por los médicos son fiebre > 38.3 °C y malestar en el niño.
Aunque únicamente 13% de los pediatras utilizan el malestar en los niños como
indicación para su administración.
Fisiología de la fiebre. La fiebre no es una enfermedad, es
un mecanismo fisiológico que tiene como beneficio alertar sobre la presencia de
un proceso infeccioso.
La fiebre retrasa el crecimiento y la reproducción
de bacterias y virus, incrementando la producción de neutrófilos y la proliferación
de linfocitos T, así como la formación de anticuerpos en la fase aguda. El
grado de fiebre no siempre se correlaciona con la severidad de la enfermedad.
Tratamiento antipirético. El uso de baños de alcohol no es
apropiado para disminuir la temperatura, ya que se han reportado eventos
adversos asociados con la absorción sistémica de alcohol. No existe evidencia que
el controlar la fiebre disminuya la morbilidad o mortalidad en enfermedades
febriles, excepto en los pacientes inmunocomprometidos, los cuales cuentan
con una limitada reserva metabólica. Finalmente, no existe
evidencia de que la terapia antipirética disminuya la recurrencia de crisis febriles.
Sin embargo, se reconoce que el uso de esta terapia sí reduce las molestias en
los niños.
Paracetamol. Después de la asociación de los
salicilatos con el síndrome de Reye, el paracetamol
(acetaminofén) reemplazó a la aspirina como
medicamento básico para la fiebre. La dosis que debe utilizase es de 10-15 mg/kg/dosis
cada 4-6 horas, por vía oral y se considera segura y eficaz en los
siguientes 30-60 minutos. Hasta 80% de los niños presentan una disminución de la temperatura en este
periodo. Las dosis altas de este antipirético en el uso clínico se han asociado
con confusión relacionada con hepatotoxicidad.
Ibuprofeno. Su uso para el manejo de la
fiebre ha aumentado. No existe evidencia que indique que exista una diferencia
significativa en la seguridad de las dosis estándar de ibuprofeno vs. paracetamol
en niños sanos de 6 meses a 12 años de edad con enfermedades febriles. La
preocupación con este medicamento es la nefrotoxicidad. En varios reportes se
describe la presencia
de insuficiencia renal cuando se trata a niños con
enfermedad febril con ibuprofeno u otro antiinflamatorio no esteroideo. En
niños con deshidratación, la síntesis de prostaglandinas inicia el incremento
de un mecanismo importante para mantener un flujo renal apropiado. El uso de
ibuprofeno o cualquier antiinflamatorio no esteroideo interfiere con los
efectos renales
de las prostaglandinas, con lo que se reduce el
flujo sanguíneo renal y potencialmente precipita o empeora la función renal.
Tratamiento con alternación o
combinación de antipiréticos.
Existe alguna evidencia de que la combinación del
tratamiento puede resultar en disminuir la temperatura por un periodo más prolongado,
pero no existe evidencia de que este tratamiento
ofrezca una mejoría en otra complicación clínica.
Los médicos que lo prescriban
a sus pacientes deberán asegurarse de no
sobrepasar las dosis indicadas para los antipiréticos utilizados.
Cuando se aconseja a una familia acerca
del manejo de la fiebre en el niño, el médico deberá disminuir la fobia por la
fiebre que tienen los padres y enfatizar que
el uso de antipiréticos no previene las
crisis febriles. Los médicos deberán enfocarse en el monitoreo de los signos y
síntomas de enfermedad grave, así como mejorar las condiciones generales del
niño como mantenimiento
de la hidratación, educación de los padres
con un uso apropiado de la dosis y almacenamiento del
antipirético.
jueves, 17 de diciembre de 2015
Embarazo a Término Nuevas Definiciones
Información para las futuras mamás sobre la
nueva definición de embarazo a término
El embarazo a término completo comienza a las 39
semanas
El Colegio Americano de Obstetras y Ginecólogos y
la Sociedad de Medicina Materno-Fetal anunciaron nuevas definiciones más
específicas para los bebés nacidos entre las 37 y las 42 semanas del embarazo.
En el pasado, si un bebé nacía entre las 37 y las
42 semanas del embarazo se consideraba "a término". Ahora, el embarazo
se considera a término completo a las 39 semanas.
¿Por qué esto es importante?
Las investigaciones muestran que los bebés que
nacen entre las 39 y las 40 semanas del embarazo tienen una mejor oportunidad
de comenzar su vida saludablemente.
Los bebés que nacen antes de las 39 semanas corren
riesgo de tener problemas de respiración, alimentación y de controlar la
temperatura del cuerpo. También es más probable que pasen tiempo en la unidad
de cuidados intensivos neonatales, desarrollen infecciones y tengan una
discapacidad de aprendizaje.
¿Por qué esto es importante para mi embarazo?
Esperar a dar a luz hasta al menos las 39 semanas
en un embarazo sano, le da a su bebé el tiempo que necesita para crecer. Los
pulmones, el hígado y el cerebro de su bebé pasan por un período muy importante
de crecimiento entre las 37 y las 39 semanas del embarazo. Esperar hasta las 39
semanas del embarazo, que ahora se llama “a término completo”, le da a su bebé
la mejor oportunidad posible para comenzar su vida saludablemente.
A veces, cuando la madre o el bebé corren algún
riesgo, es necesario planear el parto para antes de las 39 semanas de embarazo.
Sin embargo, en un embarazo saludable, lo mejor es esperar hasta por lo menos
las 39 semanas.
Es importante que conozca estos términos para que
pueda hablar con su médico acerca de lo que es mejor para su salud y la de su
bebé.
The Eunice Kennedy Shriver National Institute of Child Development. Know your terms. http://www.nichd.nih.gov/KnowYourTerms. Accessed June 8, 2014.
FUENTE:
Association of Women’s Health, Obstetric and Neonatal Nurses. 40 reasons to go the full 40 weeks. http://www.health4mom.org/a/40_reasons_121611. Accessed June 8, 2014
sábado, 12 de diciembre de 2015
La actividad física protege la función motora en personas de tercera edad
Physical Activity Protects Motor Function in Older
Adults
Clinical
Context
Motor impairment in the elderly population is common and linked to
morbidity. Public health strategies have therefore emphasized the need for
older adults to increase their physical activity level.
White matter hyperintensities (WMHs) seen on brain imaging are common in
elderly adults and are associated with level of motor function. The goal of
this cross-sectional study by Fleischman and colleagues was to test the
hypothesis that physical activity modifies the association between WMH burden
and motor function in healthy older persons without dementia.
Study
Synopsis and Perspective
Just as higher education and social connections seem to provide a
cognitive reserve as people age, physical activity may build a motor reserve
that protects against the harmful effects of WMHs in the brain on motor
function, new research suggests.
The results point to a potential biological mechanism that may at least
partly explain the well-established association between physical activity and
motor function in healthy older adults, said lead author Debra A. Fleischman,
PhD, professor, neurological sciences and behavioral sciences, Rush University
Medical Center and Rush Alzheimer's Disease Center, Chicago, Illinois.
"The data suggest that physical activity may protect motor function
from the untoward effects of small vessel disease," seen on magnetic
resonance imaging (MRI) as WMHs.
The new findings emphasize the importance of an active lifestyle in
protecting motor function from the adverse neurobiological effects of aging, Dr
Fleischman said.
Brain Volume
The study used data from 167 community-dwelling adults without dementia
who were participants in the Rush Memory and Aging Project, an ongoing
longitudinal clinical pathologic study of aging and dementia. Their mean age
was 80 years, and approximately 21% were men.
Researchers used a composite measure of global cognition from 19
individual computer-scored cognitive tests. To assess motor function, they
created a composite measure from 11 individual motor tests that included both
upper- and lower-extremity motor performance.
Using actigraphs, the investigators measured total daily activity,
including all exercise and nonexercise physical activity. Participants wore a
watch-like monitor on the nondominant wrist for 24 hours per day for up to 11
days. The data were then downloaded to a computer for analysis. Researchers
also calculated intensity of activity.
To assess WMH burden, they used a well-established, automated computer
program that measures the total volume of brain tissue affected by WMHs as
shown on fluid-attenuated inversion recovery MRI. Dr Fleischman noted that
although studies suggest that WMHs on MRI reflect small-vessel disease, more
studies are needed to characterize the pathologic bases of WMH.
After adjustment for age, gender, and education, total daily activity
was not associated with WMH burden (P = .169).
As did previous research, this study showed that a higher level of WMH
burden was associated with poorer motor function, but it also found that the
harmful effects of WMHs disappeared in active people.
Comparing participants in different percentiles of total daily activity,
they showed that in those with the highest activity (90th percentile) WMH
burden did not affect motor function. In contrast, those at the 50th percentile
of physical activity showed a negative effect of WMH burden on motor function,
and this effect was even stronger for those in the 10th percentile of activity.
The difference between the 90th and 50th percentiles is roughly an
additional 1.5 hours of walking per day at 2.5 miles per hour, Dr Fleischman
noted. And the difference between the 50th and 10th percentiles translates to
just less than 1 hour of additional walking per day.
This interaction persisted after controlling for various potential
confounding variables, including depressive symptoms, body mass index, vascular
diseases, functional status, and interactions with WMH burden.
"Together these findings suggest that higher levels of physical
activity may provide reserve against the effects of brain pathology on motor
function in older age," the authors conclude.
Dr Fleischman stressed that the association was significant when 2
different actigraphic measures were used: total daily activity and intensity of
daily activity. There was no association when physical activity was measured by
self-report.
Neural Reserve
That physical activity was not associated with WMH burden suggests that
the benefit on motor function is through a neural reserve mechanism rather than
through a direct association with WMH. Dr Fleischman suggested possible
candidate mechanisms, including increases in various trophic factors that
promote tissue survivability and genesis. However, she said, more work needs to
be done to examine the potential mechanisms underlying motor reserve.
The concept of reserve has been frequently used in relationship to
cognition. Studies show that older patients with higher levels of education,
social networks, and purpose in life have better cognitive function despite
significant Alzheimer disease pathology burden.
The same concept may be at play here: physically active people may have
the same amount of brain damage as physically inactive people, but this damage
does not seem to affect their motor function. Unlike education, however,
physical activity is a modifiable behavior at any age.
The motor reserve provided by physical activity may have an influence at
multiple sites along motor pathways. Although in the current study, the brain
proxy measure was limited to WMH burden, further studies that examine a wider
array of central nervous system abnormalities and other components of the motor
pathways "will be crucial for defining the neurobiological basis of
reserve provided by physical activity," said the authors.
The new findings underscore the importance of facilitating a more active
lifestyle to prevent late-life motor impairment, improve survivability, and
maintain independence and well-being, said the authors.
For people older than 65 years, the US Centers for Disease Control and
Prevention recommends that older adults get at least:
- 2 hours and 30 minutes
of moderate-intensity aerobic activity (eg, brisk walking) every week plus
muscle strengthening activities on 2 or more days per week that work all
major muscle groups; or
- 1 hour and 15 minutes
of vigorous-intensity aerobic activity (eg, jogging or running) every week
and muscle-strengthening activities on 2 or more days per week that work
all major muscle groups; or
- An equivalent mix of
moderate- and vigorous-intensity aerobic activity and muscle-strengthening
activities on 2 or more days per week that work all major muscle groups.
As for the type of exercise, that is an individual choice that considers
existing medical conditions and leisure-time preferences, said Dr Fleischman.
"I think that the important message, and the one that I give to my
patients, is that they do not have to be marathon runners to maintain cognitive
and motor function through physical activity as they age."
Other studies by Dr Fleischman and her research group showed that
participants with the highest level of total daily activity, no matter how this
is accumulated, are at the lowest risk for cognitive and motor impairment and
decline as they age. "So the message is to just keep moving in any way
that is safe and enjoyable."
This is particularly important because, unlike many age-related
conditions that impair motor function, such as Parkinson disease and arthritis,
age-related motor impairment is usually left untreated, said Dr Fleischman.
"Until we have a more complete understanding of the biological
mechanisms underlying chronic late-life motor impairment, and have developed
effective pharmacological treatments to lessen the effects of brain pathology
on motor function, efforts to encourage and facilitate an active lifestyle in
older adults will be a critical element in meeting this public health
challenge."
The research group is acquiring longitudinal scans that will allow them
to measure changes in all the primary variables and compare them with baseline,
said Dr Fleischman.
Physical Activity a "Panacea"?
The study is yet another example of how physical activity is a kind of
"panacea" in medicine, commented Glen Finney, MD, assistant
professor, neurology, University of Florida College of Medicine, Gainesville,
and a member of the American Academy of Neurology.
"We have seen similar effects for cognitive function and now they
have found it in the motor domain. This supports the idea that physical
activity is good for everything."
He noted that the motor function in this case is determined by the
brain. "The research clearly shows that lower levels of physical activity
are correlating with brain disease burden, so clearly this is brain-driven
motor function. But once you get to a high level of physical activity, it
actually helps to overcome and sort of negate that white matter burden."
Although the authors speculate that this is because of a motor reserve,
Dr Finney said he would like to see a prospective study look at whether it is
really a reserve or an actual treatment effect. "At this point, it's
correlation; it's not causation. It's a definite possible way this works,"
he said.
According to an accompanying
editorial, the "pooled approach" of using a
composite motor score and a range of cognitive tests is statistically powerful
but needs further development to be accessible in routine clinical practice.
The editorial writers, Richard Camicioli, MD, Department of Medicine,
Division of Neurology, University of Alberta, Edmonton, Canada, and Joe
Verghese, MB BS, MS, Departments of Neurology and Medicine, Albert Einstein
College of Medicine, Bronx, New York, noted that the 167 participants were more
educated and cognitively healthy although slightly older than the overall
sample of 1545 persons originally recruited for the study.
They also commented that because the study was cross-sectional, it
cannot determine causality. In addition, they note, actigraphy measures total
activity, so it is difficult to know which aspects of the activities were
protective.
"The nature (aerobic or resistance), complexity (dancing), or
frequency of the physical activity may all have a role," they said.
Measuring WMHs by fluid-attenuated inversion recovery imaging may not
completely reflect white matter damage, they said. Diffusion tensor imaging or
magnetization transfer imaging may better depict white matter damage, might
provide complementary measures, and may be related to physical activity.
The study was supported by the National Institute on Aging, National
Institute of Minority Health and Health Disparities, Illinois Department of
Public Health, and Rush Translational Science Consortium. The study authors and
editorial writers have disclosed no relevant financial relationships.
Comentario:
De nueva
cuenta un estudio demuestra la importancia del ejercicio en personas de tercera
edad, enfatizando sus beneficios a nivel cerebral y motor.
Este
estudio demuestra una vez más que la actividad física es una especie de Panacea
en Medicina.
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