Radiation-induced Skeletal Muscle Injury: Report 1 Case

Objective: To reason the nosogenesis, clinicalcharacteristics, feasible ways of treatment and possibleprognosis on radiation-induced skeletal muscle injury.Method: One case was carried out by excision of majorpectoral muscle.Result: Clinical symptom relieved, and no recurrenceoccurring.Discussion: As one type of all the radiation-inducedinjury diseases, radiation-induced skeletal muscle injurysingles itself out by its unclear early symptoms and its lowdisease incidence. Its major symptom involves muscle atrophy,ache, edema, medium to severe muscle weakness. For thetime being, there is no definite nosogenesis, no systematicdiagnosis or specific way of treatment, or exact curative effectrecorded concerned.Nosogenesis: According to ionizationradiation-histopathology, cells can be classified into fivecatagaries based on their propagation and their radiationsensitivity. Primitive cells tend to perform more activemultiplicative division, more radiation sensitivity, less antira-diation ability,and hence are more liable to indulge radiationinjury. On the contrary high level of cell differentiation leads toless active multiplicative division and radiation sensitivity,better antiradiation ability,and more reluctance to indulgeradiation injury. Different tissues and organs comprise quitediverse cell construction, where more procells show moreactive multiplicative division, more radiation sensitivity, lessantiradiation ability,and hence are more liable to indulgeradiation injury, or where, high level of cell differentiation leadsto less active multiplicative division and radiation sensitivity,better antiradiation ability,and more reluctance to indulgeradiation injury.No definite nosogenesis found so far. The following factorsare supposed to take credit for this special case:1. Radiation-induced Cell DeathBroken DNA double-strand of nucleus and blockedcaryocinesia intrigued by radiation can result in cell death.DNA double-strand breaking stands as a most significantdamage of all the apoptosis form caused by radiation. At thesame time ionization radiation indirectly causes free radicle tobuild up in the cells concerned, which leads to stable molecule,and hence leads to cell death. Due to the hardiness of skeletalcells to radiation, radiation-induced micrangium damage andintercellular substance change occur before skeletal celldamage.2. Radiation-induced Micrangium DamageIn many cases, radiation-induced micrangium damageworks as a key, or a trigger, to normal tissue and organdamage caused by radiation. Medium radiation-induceddamages on micrangium and connective tissue can lead toarterial capillary and interstitial fibrosis. Radionuclideexperiments prove a clear decline in the amount ofmicrocirculation available. Large dose of irradiation rapidlydecreases blood circulation within microvascular (Due topropagation of the endotheliocyte and the formation ofthrombin, lumens are likely to be blocked),and thereforeblood-supply tissue tends to indulge necrosis. Early stagedradiation injury effect of microvascular mainly appears asinflammatory reaction, while a late one will involve propagation,swelling, cataplasis, and necrosis of endotheliocyte, basallamina thickening, lumens stegnosis, or even obliteration.Vascellum edema in the early period increases interstitial fluidand the chance of fibrosis. Constructive disorganization ofmicrangium often results in an early haemorrhage, whichcrushes the parenchyma cells inevitably. Blood corpuscle hasa negative effect on the active compound relieved, and theproteolytic enzyme from cytolysosome also damagesparenchyma cells. Thus, parenchyma cells suffer from asevere alogotrophy and end up affecting cell functionnegatively and even causing cell degeneration and necrosis.3. Changes of Intercellular Substance from Radiation.Under radiation, aminohexose and hydroxyproline mountin a way and therefore increase the possibility of organicfibrosis.4. Never Injury Under Radiation.Although no definite reason is found up to date concerningnerve injury, we can focus on two major factors: that of thedirect coup injury from radiation and that of the nutrient vesseldamage around nerve, and vasculitis such as vessel obligationand hardening. These nerve injuries cause skeletal muscle tolose its innervations and trophism, and its contractive ability inturn. A successive happenings turn up of gradual atrophy,volume decrease, protein catabolism increase in stead, sectionarea of muscle fiber myoprotein proportion and muscle humidweight decrease, enzyme activity of Na+-K+-ATP and Ca2+-ATPincrease, fibrillation potential occurrence, and finally thenecrosis and fibrosis and total disfunction of skeletal muscle.Due to the factors mentioned above, cells involved getenglobed by neighboring parenchyma cells or macrophages,and decline in number. Therefore, skeletal muscle atrophy andweakness are likely to happen afterwards. An early damage ofblood capillary explains the exosmosis of hematoplasma andtissue edema, which hence cause pain and skeletal edema.Meanwhile, change in intercellular substance induces skeletalfibrosis.Clinical characteristics: With a radiation history andundefined intermissions of muscle atrophy, pain, edema, andmedium to severe muscle weakness.Treatment and prognosis: Difficult to cureradiation-induced skeletal muscle injury. Irreversibilitycharacterizes this kind of pathological change and leadsinevitably to two major ways to treatment: the expectant(physical therapy with proper medicine)and the operation. Theexpectant can effectively control pathogenetic condition fromdeterioration, while not totally reverse it. Delay in diagnosticateoften brings a case level 2 or above, which won't respond wellto the expectant treatment. The operation treatment can relievethe symptoms, while not compensate for the loss of functionscaused by skeletal missing.Conclusion: No effective method is found up to datedue to the tardiness, anamorphosis and irreversibility ofradiation-induced skeletal muscle injury. It is a must to divemore into the nosogenesis of this disease, to come up with aneffective way of treatment, and for the time being to investmore precautions against it.