By K. Varek. Bryant College.
There are several anecdotal guidelines available in the literature purchase fincar 5 mg overnight delivery prostate cancer gleason 7. As mentioned above fincar 5mg mastercard androgen hormone action, these are not supported by published scientific evidence and should be considered management “options” at best. The main return to sport after repeated concussive injury guidelines are those published by Cantu8,9 and the Colorado Medical Society. It can be seen that there are many superficial similarities between the two scale systems. Although the criteria for injury severity differ, the mandatory requirement is that two Grade 3 injuries or three injuries of any grade result in termination of the athletes season. Given that a Cantu Grade 2 is equivalent to a Colorado Grade 3, it can be seen that the scales give differing recommendations for the same injury. The physiology of concussion The effects of diffuse injury to axons and neurones sustained at the time of head injury may or may not be reversible depending on the magnitude of the blow. Some authors have suggested that strains produced by all head injuries result in axonal injury. Cantu system (adapted from 9) Severity grade 1st concussion 2nd concussion 3rd concussion Grade 1 RTP after 1 week if RTP in 2 weeks if Terminate season. RTP if RTP next season LOC < 5 min, PTA at least 1 week asymptomatic for if asymptomatic > 30 min at least 1 week. Consider terminate season Grade 3 Minimum of 1 month Terminate season. RTP if RTP next season if LOC > 5 min, asymptomatic for asymptomatic PTA > 24 hrs at least 1 week PTA = post traumatic amnesia, LOC = loss of consciousness, RTP = return to play Table 5. Colorado guidelines (adapted from 10) Severity grade 1st concussion 2nd concussion 3rd concussion Grade 1 RTP after 20 mins if RTP if asymptomatic Terminate season. Although experimental research has enhanced our understanding of the physiological changes to the brain following severe head 69 Evidence-based Sports Medicine trauma, there still remains uncertainty as to what is happening to the brain following minor concussive injuries and in particular, sport related concussion. The neuropathology of concussion The nature of transient loss of cerebral function following a blow to the head has excited much speculation over the centuries directed as to whether microscopic neuropathological changes occur or whether other cerebral pathophysiological processes manifest the clinical symptoms of concussion. At this stage these important issues remain unresolved. In general terms, although minor neuropathological changes may occur following concussive brain injury the clinical symptoms are due to functional disturbance, presumably at the cell membrane level, rather than due to any structural injury. This is supported by experimental evidence demonstrating that mechanical stress can produce a sudden neuronal depolarisation, followed by a period of nerve cell transmission failure in the absence of structural injury. In the handful of case reports of persons dying from other causes following brain injury, scattered neuronal cell death may be demonstrated. The findings however, are generally insufficient to explain the degree of clinical dysfunction, suggesting the clinical symptoms are manifest by additional functional cell impairment. The neuropsychology of concussion It is only in the past few decades that there has been interest in studying the neuropsychological consequences of concussion, particularly those injuries seen in sport. While there is now acceptance of an organic basis to the problems associated with concussion, controversy remains regarding the nature of the cognitive deficits as well as the speed and extent of their recovery. The major areas of deficit include: • Disturbances of new learning and memory19,20,25,29–35 • Planning and the ability to switch mental ‘set’29,32,34,36 • Reduced attention and speed of information processing. While ongoing neuropsychological deficits have been reported by some researchers at one month,30,44,51,52 other workers have reported normal neuropsychological performance20,38,48 or performance at pre-injury levels by this time. MacFlyn et al reported complete recovery at six months44 and Dikmen et al by one year. In the various studies, a wide variation in severity of injury has been included under the rubric of concussion ranging from no LOC or mild stunning of the sensorium for a few seconds32,34,37,40,53,55 to periods of PTA for 24 hours or LOC for 20 minutes29,38,44,46 through to cases with PTA of 6 days,22 4 weeks,57 and 4 months45 and loss of consciousness for at least one week. This heterogeneity may account for some of the differences between studies since the magnitude of the head acceleration forces may differ considerably depending upon the cause. The first proposes that the symptoms associated with PCS are a direct consequence of brain injury,65,66 whilst the second proposes that the symptoms are functional and represent psychological or emotional sequelae of the brain injury. The issue of malingering and compensible litigation is also often proposed as a mechanism for symptom prolongation. Whether this relates to different impact forces as compared to motor vehicle crash studies remains speculative.
The citrulline The gut also uses dietary aspartate and glutamate order 5mg fincar with visa androgen hormone norepinephrine, which enter the TCA cycle cheap 5 mg fincar mastercard prostate cancer ketogenic diet. The importance of the gut in whole body nitrogen metabolism arises from the Glutamine utilization by the gut is high rate of division and death of intestinal mucosal cells and the need to continu- diminished by a metabolic acidosis ously provide these cells with amino acids to sustain the high rates of protein syn- compared with the postabsorptive thesis required for cellular division. Not only are these cells important for the uptake or postprandial states. During metabolic aci- dosis, the uptake of glutamine by the kidney of nutrients, but they maintain a barrier against invading bacteria from the gut lumen is increased, and blood glutamine levels and are, therefore, part of our passive defense system. As a consequence, the gut takes functions, the intestinal mucosal cells are supplied with the amino acids required for up less glutamine. Liver The liver is the major site of amino acid metabolism. It is the major site of amino acid catabolism and converts most of the carbon in amino acids to intermediates of the TCA cycle or the glycolytic pathway (which can be converted to glucose or oxi- dized to CO2), or to acetyl CoA and ketone bodies. The liver is also the major site for urea synthesis. It can take up both glutamine and alanine and convert the 774 SECTION SEVEN / NITROGEN METABOLISM nitrogen to urea for disposal (see Chapter 38). Other pathways in the liver provide it with an unusually high amino acid requirement. The liver synthesizes plasma pro- teins, such as serum albumin, transferrin, and the proteins of the blood coagulation cascade. It is a major site for the synthesis of nonessential amino acids, the conju- gation of xenobiotic compounds with glycine, the synthesis of heme and purine nucleotides, and the synthesis of glutathione. AMINO ACID POOL AND NEUROTRANSMITTER SYNTHESIS A major function of amino acid metabolism in neural tissue is the synthesis of neu- rotransmitters. More than 40 compounds are believed to function as neurotransmit- ters, and all of these contain nitrogen derived from precursor amino acids. They include amino acids, which are themselves neurotransmitters (e. In general, neurotransmitters are formed in the presynaptic terminals of axons and stored in vesicles until released by a transient change in electrochemical potential along the axon. Subsequent catabolism of some of the neurotransmitter results in the formation of a urinary excretion product. The rapid metabolism of neurotransmitters requires the continuous availability of a precursor pool of amino acids for de novo neurotransmitter synthesis (see Chapter 47). METABOLISM OF GLUTAMINE IN THE BRAIN The brain is a net glutamine producer owing principally to the presence of gluta- mine synthetase in astroglial cells (see Chapter 47). Glutamate and aspartate are synthesized in these cells, using amino groups donated by the BCAA (principally valine) and TCA cycle intermediates formed from glucose and from the carbon skeletons of BCAA (Fig. This glu- tamine may efflux from the brain, carrying excess NH4 into the blood, or serve as a precursor of glutamate in neuronal cells. Blood- brain Blood barrier Astroglial cell Neurons BCAA BCAA α–KG Purine nucleotide BCKA Glutamate cycle GABA + + glutamine NH4 NH3 NH3 NH4 synthetase + CO2 NH4 Glutamine Glutamine Glutamate Fig. Glutamine serves as a nitrogen transporter in the brain for the synthesis of many different neurotransmitters. Different neurons convert glutamine to -aminobutyric acid (GABA) or to glutamate. Glutamine also transports excess NH from the brain into the blood. BCKA branched-chain keto acids; -KG 4 -ketoglutarate. CHAPTER 42 / INTERTISSUE RELATIONSHIPS IN THE METABOLISM OF AMINO ACIDS 775 Glutamine synthesized in the astroglial cells is a precursor of glutamate (an exci- During hyperammonemia, ammo- tatory neurotransmitter) and GABA (an inhibitory neurotransmitter) in the neuronal nia (NH3) can diffuse into the brain cells (see Fig. It is converted to glutamate by a neuronal glutaminase from the blood. The ammonia is able to inhibit the neural isozyme of glutam- isozyme. In GABAergic neurons, glutamate is then decarboxylated to GABA, inase, thereby decreasing additional ammo- which is released during excitation of the neuron. GABA is one of the neurotrans- nia formation in the brain and inhibiting the mitters that is recycled; a transaminase converts it to succinaldehyde, which is then formation of glutamate and its subsequent oxidized to succinate. This effect of ammo- nia might contribute to the lethargy associ- ated with the hyperammonemia found in III.
For the moderately or more severely involved abduction contracture defined as those with less than 45° of hip flexion and less than 0° of hip ad- duction cheap fincar 5 mg visa man health report, a varus shortening osteotomy to reposition the lower extremity should be included in the treatment discount fincar 5 mg free shipping prostate gland removal. This osteotomy should be the primary procedure for adolescents who have neared skeletal maturity and for chil- dren who have had protrusio acetabuli. Again, the rehabilitation following this procedure should focus on getting children back up into the wheelchair quickly, working on range of motion to maintain the adducted position, and working on hip flexion. These are the primary postures that need to be cor- rected to have good sitting posture. Hip Flexion Contracture Fixed hip flexion contracture is a very common deformity present in adoles- cents or young adults who have CP and spend almost all their time sitting in a wheelchair. This deformity becomes part of their wheelchair posture. If in- dividuals are nonweight bearing, the flexion contractures themselves are not usually of much significance. For adolescents or young adults who are doing transfers or household ambulation, a hip flexion contracture of 30° to 40° is usually well tolerated by compensatory lumbar lordosis and does not need to be treated. For children who ambulate independently, a hip flexion con- tracture that yields a Thomas test of 20° to 30° often causes increased lor- dosis and prevents full hip extension in midstance phase, and is therefore somewhat restrictive. In this situation, lengthening the hip flexors may be in- dicated, but care should be taken that the disability from loss of hip flexion power is not greater than the flexion contracture. Occasionally, some chil- dren or adolescents develop severe hip flexion contractures up to 90° to 100°. However, this is quite rare in individuals who do not have some concomi- tant paralysis. This pattern of contracture is primarily encountered in those individuals who have concomitant spinal cord injury or spina bifida with their spasticity. When this type of severe hip flexion contracture develops, it 10. Hip 597 is almost always in the context of an equally severe knee flexion contracture, and if treatment is contemplated, both must be addressed simultaneously. Assessment and Measurement of Hip Flexion Contracture Several different techniques for measuring hip flexion contracture have been proposed and evaluated; however, each technique has its positives and neg- atives. Techniques are rated on variable ease of use, reliability, and repro- ducibility. The supine test in which the opposite leg is flexed to flatten the lumbar lordosis and the hip flexion recorded, known as the Thomas test, is the easiest to use in an outpatient clinic. The prone hip flexion test is done with a child lying prone as both legs are dropped off the end of the bed so that the lumbar lordosis is reduced. With the child in the prone position and both hips flexed, one leg is gradually extended until movement is pal- pated in the pelvis (Figure 10. This test may be slightly more accurate and A Figure 10. Physical examination measure of hip flexion contracture is often difficult. The prone hip flexion test as described by Staheli is useful for a smaller and cooperative child (A). For an uncooperative child or a very large individual, the supine test as de- scribed by Thomas is easier and reasonably reliable (B). For chil- dren who can stand independently, radiographic measurement of the lum- bosacral femoral angle can be used (Figure 10. This is the measure we prefer when wanting to carefully measure hip flexion contracture in stand- ing individuals, although it is still difficult to determine whether this increased sacral femoral angle is due to hip flexion contracture or caused by a com- pensation for lumbar lordosis. Etiology The etiology of hip flexion contracture in individuals who are nonambula- tory and spend all their time sitting in a wheelchair is that they are not get- ting stretched out of that wheelchair posture. For these children, learning to spend time in the prone, stretched-out position, especially at night as they are growing, is important. Also, many adolescents who are going through their adolescent growth spurt are gaining weight and becoming heavier, and there is a tendency for caretakers and school personnel to stop placing them in standers and stretching them out because of the difficulty in moving the children. As a consequence, these individuals are spending increasing time in the wheelchair seating position and less time getting out of the wheelchair and having their hip flexors stretched out either by prone lying or by ther- apy exercises during their most rapid growth period.
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