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Biomedical subjects

P A McGrath

Publications and source records attributed to P A McGrath.

At least 19 recordsLinked to original sources
PubMed2001

Chronic daily headache in children and adolescents.

Chronic daily headache (CDH), an almost continual headache in the absence of organic pathology, is an exceptionally challenging type of headache to treat in children and adolescents. CDH has different expressions in children and adults; the different expressions may reflect several different etiologies or a developmental continuum. Although a positive family history predisposes children to develop headache, many environmental, biological, and psychological processes may share a role in the etiology. To date, no studies have examined the pathophysiology of CDH in children so that our understanding is presumed, rather than documented, and based primarily on extrapolation from adult studies. For some cases with migraine features, presumed mechanisms include a neurogenic inflammatory cascade, vascular reactivity, and serotonin, whereas for other cases, mechanisms may include pericranial muscle tenderness or musculoskeletal abnormalities, as noted recently for adults. A skilled and careful history is the first step to ensuring an accurate diagnosis for children with CDH. Pain assessment is an integral component of diagnosis and treatment. We need an objective measure of headache activity and an understanding of the factors that cause or exacerbate headaches for an individual child. Although many drug and nondrug therapies are available for treating children's headache, we lack data about which therapies are best for children with CDH or its subtypes. The current principles guiding our management of CDH in children and adolescents are extrapolated from the existing literature on childhood headache, CDH in adults, and our clinical experience. A child-centered focus is particularly important in the treatment of CDH because it is not caused by an underlying disease or disorder.

Adolescent↗
PubMed1996

Development of the World Health Organization Guidelines on Cancer Pain Relief and Palliative Care in Children.

Assess pain regularly throughout the course of treatment. Follow the WHO Analgesic Ladder for selecting pain-relief drugs, that is, a stepwise approach to analgesic management, where a child's pain severity determines the level of analgesics. Use practical cognitive, behavioral, physical, and supportive therapies, combined with appropriate drug treatment. Administer adequate analgesics doses "by the clock," that is, at regular times, not PRN. Use oral routes for administering analgesics, and avoid painful routes of administration, whenever possible. Administer a sufficient analgesic dose to allow children to sleep throughout the night. Anticipate and treat side effects aggressively.

Child↗
PubMed1995

Pain in the pediatric patient: practical aspects of assessment.

A child's pain is plastic and complex. In order to more effectively alleviate suffering, emphasis must shift from an exclusive focus on the source of tissue damage to a more comprehensive focus that includes factors that modulate pain. Evaluating a child's pain requires an integrated approach. Clinicians always should ask a child directly about his or her pain experience to determine the sensory characteristics. Clinicians also should assess situational factors to develop strategies to modify their impact. Then, a child's pain intensity should be measured regularly to monitor the effectiveness of interventions. Interviews, structured questionnaires, and simple rating scales are the primary tools to assess pain for most children older than 5 years of age. For infants, toddlers, and cognitively impaired children, physicians must infer the presence and severity of pain by evaluating changes in children's behavioral and physiological states. Parents and the health professionals who work most closely with children with particular handicaps can provide valuable information about the presence and severity of a child's pain because they often can recognize extremely subtle behavioral cues that indicate distress. A standardized but flexible approach is necessary to assess a child's pain. Pain assessment, like pain management, is a continuous process. Pain intensity rating scales should be used so children can provide a direct rating of their pain intensity and pain effect. Patients should receive some guidance about how to use the information from rating scales to develop consistent and objective criteria to know when children require analgesics and then to evaluate the effectiveness of those medications.

Adolescent↗
PubMed1994

Psychological aspects of pain perception.

Interest in the assessment and management of pain increased dramatically after 1965, when the gate control theory was introduced. This increase is concurrent with enormous advances in our understanding of the plasticity and complexity of pain processing. New information about internal pain-inhibitory systems and the factors that trigger them has revolutionized traditional approaches to pain control. This article describes some of the new information on the factors that influence human pain perception, specifically the environmental and psychological factors that modify how pain is experienced. Pain is a complex, multidimensional perception that varies in quality, strength, duration, location, and unpleasantness. The strength and unpleasantness of pain is neither simply nor directly related to the nature and extent of tissue damage. Even newborn infants may experience different pains from the same stimulus, because of the differences in the situations in which it is administered. Pain experiences can range from an inability to perceive pain, regardless of the strength of stimulation, to the actual perception of pain in a limb that has been amputated. The perception of, expression of, and reaction to pain are influenced by genetic, developmental, familial, psychological, social and cultural variables. Psychological factors, such as the situational and emotional factors that exist when we experience pain, can profoundly alter the strength of these perceptions. Attention, understanding, control, expectations, and the aversive significance can affect pain perceptions. Consequently, the understanding of pain requires not only understanding of the nociceptive system, but recognition and control of the many environmental and psychological factors that modify human pain perceptions.

Acute Disease↗
PubMed1992

Phantom limb sensations in adolescents: a case study to illustrate the utility of sensation and pain logs in pediatric clinical practice.

Although the nature of pain following amputations has been well documented for adults, little research has been conducted to determine the incidence, prevalence, and nature of phantom limb sensations and pains in children and adolescents. This case study documents the nature of phantom limb sensation (intensity, quality, location, duration, and frequency) for a 15-yr-old adolescent after leg amputation. She completed a brief sensation/pain log, consisting of quantitative and qualitative scales, for 28 days after surgery. She experienced phantom limb sensations, which spread from her toes to encompass her entire leg by day 10 after surgery. The pattern of spread was not consistent throughout this period. The quality of sensations remained relatively constant and was described as itching and tingling. The phantom sensations were not experienced consistently throughout the day, but were experienced as discreet episodes. Both the duration and frequency of these episodes decreased throughout the 28 days. Similarly, the intensity of her phantom sensations decreased gradually throughout this period. This case study illustrates how it is possible to integrate research with health care delivery in a practical manner, to obtain prospective information about the nature of childhood sensory experiences.

Adolescent↗
PubMed1992

Pediatric pain: interacting behavioral and physical factors.

Pain in infants, children, and adolescents warrants study from a developmental, behavioral, and physiological perspective because maturation of physical, emotional, and cognitive systems influences the way in which pain is experienced and expressed. Pediatric pain is an underdeveloped area ripe for study within the realm of developmental and behavioral pediatrics, as noted by documentation of its undertreatment in children. The focus of this paper is to present issues relevant to the study of pain in children, using the example of the recurrent abdominal pain syndrome to illustrate points regarding epidemiology, assessment, and intervention. It is the opinion of these authors that pediatric pain must be understood from a developmental perspective in both clinical and nonclinical populations of children. Multidisciplinary approaches to research in pain aids in understanding the development of nociceptive transmission and inhibitory systems, the development of pain expression, and the influence of context on pain experience and behavior. The goal of research in pediatric pain is to understand these systems within a developmental context so that preventive and therapeutic intervention strategies can be developed to reduce children's distress and pain-related disability.

Abdominal Pain↗
PubMed1989

Evaluating a child's pain.

Much recent attention has focused on the development and refinement of pain measures, as well as on the use of more effective pain control methods for infants, children, and adolescents. This article reviews the primary categories of pediatric pain measures, with a specific focus on the selection of the most appropriate behavioral, physiologic, or subjective method for assessing a child's pain. The optimum pain measure depends on the age and cognitive level of a child, the type of pain experienced, and the situation in which the pain occurs. While no single measure is adequate for all children for all types of acute, recurrent, and chronic pain, it is possible to choose practical, valid, and reliable methods for evaluating any child's pain experience.

Child↗
PubMed1989

The enigma of pain in children: an overview.

During the last 2 decades, a vast amount of information has been obtained about the sensory system responsible for pain perception, with the result that there have been dramatic changes in the understanding of how pain is experienced and how pain can be modified. However, recent advances in the management of pain have been confined almost exclusively to adults. Consequently, our understanding about pain perception in infants, children and adolescents, our knowledge about the prevalence of different pain problems for children and data about the effectiveness of various pharmacological and nonpharmacological pain control methods are limited. This article explores the issue of the undertreatment of acute, recurrent, chronic and cancer pain in infants and children.

Child↗
PubMed1986

Effect of epidermal growth factor on the membrane potential of cultured porcine thyroid cells.

Cultured porcine thyroid cells maintained in media containing TSH exhibited a membrane potential of -50 mV, and hyperpolarized by about 10 mV within 1 h of the addition of epidermal growth factor (EGF; 10 ng/ml). Follicle cells had depolarized to -45 mV after 4 h of exposure to EGF. Cells maintained in dibutyryl cyclic AMP (dbcAMP) did not alter their membrane potential when exposed to EGF for up to 4 h. Cultures washed to remove the TSH or dbcAMP hyperpolarized to -75 mV within 30 min, and a reversible depolarization to -60 mV was observed on addition of EGF. It was concluded that EGF acts as a physiological antagonist of TSH and also exerts a separate depolarizing influence on cultured thyroid cells.

Animals↗
PubMed1985

Electrical responses of cultured porcine thyroid cells to adrenergic agents.

The membrane potential of cultured porcine thyroid follicular cells depolarized by up to 20 mV from the resting value of about -73 mV on exposure to beta-adrenoceptor agonists. A similar response was induced by TSH or dibutyryl cyclic AMP. alpha-Adrenoceptor agonists were without effect. The receptor subtype was shown to be (at least predominantly) beta 2 by the order of potency for beta-agonists (isoprenaline approximately equal to fenoterol much greater than adrenaline greater than noradrenaline) and by the relative potency of selective beta-antagonists (ICI 118,551 much greater than atenolol). The alpha-agonist phenylephrine had no effect on the TSH response but weakly inhibited the beta-agonist response. Rather than a physiological antagonism between alpha- and beta-adrenoceptor-mediated responses, this effect was shown to be due to the weak beta-antagonist effect of phenylephrine since the alpha-antagonist phentolamine failed to potentiate the depolarizing response to the mixed agonist noradrenaline, and also failed to block the inhibitory action of phenylephrine on the beta-agonist effect. Sensitivity to beta-agonist was enhanced by omission of serum from the culture medium and reduced by exposure to beta-agonists or a high concentration of TSH or dibutyryl cyclic AMP.

Adrenergic beta-Agonists↗
PubMed1985

Electrical responses of cultured thyroid cells to serotonin.

Cultured porcine thyroid cells, maintained in the differentiated state by dibutyryl cyclic AMP, responded to serotonin (5-HT; 10 nmol/l to 1 mumol/l) with a depolarization of the membrane potential, but did not respond to histamine (100 mumol/l) or dopamine (1 mumol/l). The resting membrane potential of these cells was about -71 mV, maximal concentrations of 5-HT (1 mumol/l) inducing a depolarization to approximately -53 mV. Methysergide or phenoxybenzamine, but not propranolol, abolished the response to 5-HT. Sensitivity to 5-HT was reduced by previous exposure of cultures to TSH, the beta-adrenoceptor agonist salbutamol or 5-HT itself.

Albuterol↗