Hypothermia rs

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Presentation on forensic significance of hypothermia

Transcript of Hypothermia rs

  • 1. Rijen Shrestha 20-08-2068

2. Introduction Definition:Hypothermia is the condition of the body where thecore temperature of the body is below 35o C Indifferent temperature: Ambient Temperature at which basal metabolic rate is sufficient to maintain normal body temperature. 3. Dimaio and Dimaio 2001 Normal body temperature: 98.6 F (37 C) orally Newborns and the elderly have temperatures averaging 1 C higher. Cyclic changes in body temperature occur with decreases of 0.5 C earlyin the morning (approximately 1:00 to 2:00 a.m.) and slight elevationslater in the morning and afternoon.A Guyton and JE Hall in 2000, and HB Simon in 1993 Exercise can raise the rectal temperature up to 104 F. Rectal temperatures of 3940 C are common in marathoners after arace.Mackowiak et al. 98.2 F (36.8 C) is the mean normal oral temperature, with 99.9 F(37.7 C) the upper limit. Maximum temperatures varied with time of day with a low in the earlymorning. 4. EpidemiologyWinters as well as during spring or autumn in colderperiods.Outdoors as well as indoors Senile mental deterioration and immobility in elderly Risk Lack of fuel for heating Open windows for fresh airFactors Intoxication New born babies Hazardous outdoor activities 5. Factors affecting development of hypothermia: Difference in temperatures Surface area/Volume ratio Children > Adults Stored heat Medium of transfer 6. 4 clinical phases of hypothermiaPhase 1Phase 2Phase 3 Phase 436oC 33oC33oC 30oC30oC 27oCBelow 27oCMuscular SystemDrop of muscular Rise of muscular ShiveringtonusrigidityEither further decrease of vital HeartTachycardiaSinus bradycardia Bradyrrhythmiafunctions orcardiocirculatory arrest or ventricularfibrillation orRise of resistance due asystoliaReduced perfusion of Rise of resistance dueCirculation to increased viscosity body surface to vasoconstriction of blood Stimulation ofBradypnoea, apnoic Central Depression ofCessation ofVentilation respiration; pause; Decrease ofventilationbreathing. ApnoeaHyperventilation complianceRaised vigilance, Disorientation,Unconsciousness, lossNervous system Confusion; Painful apathy; Passing off of reflexacra painExcitation ExhaustionParalysis Vita reducta apparent death 7. Mechanism 8. Guidelines for examinationExamination of organs which contribute to bodytemperature Thyroid AdrenalBio-chemical changes due to counter-regulatorymechanism Loss of glycogen in various organs Release of catecholamines and excretion in urine Fatty changes in organsExamination of organs responsible for death Myocardial damage 9. Guidelines for examinationExamination of freezing tissue and tissue at surface-core border Frost erythema Muscle bleeding in core musclesOther organ damage ( Cold stress) Hemorrhagic gastric lesions Pancreatic changes Hemorrhagic infarcts Micro-infarcts 10. Morphological changesLeft shifting of O2-Hb dissociation curve Bright red color of blood and lividity Blood in left ventricle is bright redPost-mortem artifacts Cutis anserina Skull fractures due to freezing of brainHemorrhages and erythemas Frost erythema Hemorrhagic gastric erosions Hemorrhagic pancreas Hemorrhages into core muscles Hemorrhage into synovial fluid 11. Morphological changesFatty changes Liver Heart KidneysUnspecific changes Brain oedema Sub-endocardial hemorrhage Pneumonia Contraction of spleenCounter-regulation mechanisms Vacuolization and loss of glycogen in cells of liver, pancreas, renal proximal tubules and adrenal cells Colloid depletion and activation of thyroid 12. Blood changesBright red color of blood Non-specific finding Mechanism:Mechanism: Left shifting of O2-Hb dissociation curveBlood in left ventricle appears bright red Non-specific finding Mechanism:Mechanism: Blood in the left ventricle comes from the lungs where itwas cooled down 13. Skin changesSkin changes in general hypothermia aredifferent from those in local hypothermia Local HypothermiaMechanism: Freezing of tissue and obstruction of blood supply tothe tissueMicroscopically: Damage of endothelial cells Leakage of serum into tissue Sludging of red blood cells 14. Three grades of local hypothermiaDermatitis congelationis erythematosa Violaceous discolorationDermatitis congelationis bullosa Blisters filled with clear or bloody fluidDermatitis congelationis gangrenosa Bluish discoloration with blister formation and tissuenecrosis 15. Skin Changes in General hypothermia Frost-bite like injuries Swelling over the nose, ears, hands Red or purple skin lesions and violet patcheson knees and elbows or at outside of the hipjointMechanism: Capillary damage and leakage of plasmaalong with hemoglobin Frost erythema differs from hemorrhagedue to lack of erythrocytes. 16. Gastric mucosal changes Wischnewsky in 1895 Multiple hemorrhagic gastric lesions as a sign indicative of hypothermia Lesions vary from 1 mm to 2 cm in diameter Lesion vary from a few to up to 100 in number Lesions must not be mistake for true hemorrhagic erosions F. Buchner in 1943 Wischnewsky spots were characterized by necrosis of mucosa with hematin formation 17. Wischnewsky spotsJ Hirvonen and R Elfving in (1974)Preu J, Dettmeyer R, Lignitz E, Madea B (2006) Mechanism: Disturbances of microcirculation (hemoconcentration) Tissue amines histamine and serotoninJP Sperhake et al in 2004M Tsokos et al in 2006 Wischnewsky spots are immunopositive for hemoglobin Mechanism Circumscribed hemorrhages of the gastric glands phase autolysis of RBCs release hemoglobin which is hematinized onexposure to gastric acid to form blackish-brown spots. 18. Frequency of Wischnewsky spots in studies Author of studyN%Wischnewsky, 1895 40/44 90.9%Krjukoff, 191444/61 72%Mant, 196937/43 86%Gillner and Waltz, 1971 22/25 88%Hirvonen, 197610/22 45%Thrun, 1992 21/23 91.3%Birchmeyer and Mitchell, 1989 1560%Takada et al. 19911788%Dreler and Hauck, 1996 2986%Kinzinger et al. 1995 3040%Mizukami et al. 19992344%Bonn and Greifswald,117/145 80.7% 19. Other Gastro-intestinal lesions 20. Pancreatic changes in hypothermia Focal or diffuse pancreatitis Hemorrhagic pancreatitis Patches of fat necrosis over organ surfaces Increased serum amylase Hemorrhages and focal or diffuse interstitial leucocyticinfiltrationAt autopsy, Hemorrhages into the pancreas parenchyma as well asunder the mucosa of the pancreatic duct may be seen. Preu et al. 24 out of 62 cases of fatal hypothermia (38.7%) empty vacuoles in the adenoid cells of pancreas 21. Hemorrhage into core muscles Dirnhofer and Sigrist (1979)Hemorrhages into muscles belonging to the core of the bodycan be used as a diagnostic criterion of death due tohypothermia.Histology Vacuolated degeneration of subendothelial layers of the vascular walls with a lifting of epithelial cells Misbalance of reduced perfusion and normal oxygen requirement causes hypoxic damage of epithelial cells with resultant raised permeability 22. Lipid accumulation Fatty changes in heart, liver, and kidneys have beendescribed in fatalities due to hypothermia Lipid accumulation in epithelial cells of proximalrenal tubules seem to be of high diagnosticsignificance Base of the epithelial cells strong positive correlation between the grade of fatty change with the occurrence of macroscopic signs of hypothermia 23. Grade 0 (x200)fatty degeneration Grade +1 (x200)of renal tubulesGrade +2 (x200)Grade +3 (x200) 24. Grade 0Fatty changes of Grade +1 cardiac myocytesin hypothermiaGrade +2Grade +3 25. Grade 0Lipofuscin staining Grade +1 of cardiomyocytesGrade +2 Grade +3 26. Endocrine glandsEndocrine glands are responsible for the maintenance of normalbody temperatureMorphological findings can be expected only in long-lastinghypothermiaF Buchner in 1943 no morphologic changes detected after exposure to cold temperatures for 49 hours activation of thyroid observed after long lasting exposure (59 days with temperature drops from 37.5 to 36oC)morphologic changes: lipid depletion of adrenal cortex found after 10 days with core temperatures of 33oC) not after short exposures of 47 h depletion of colloid, raise of epithelial cells). 27. ConclusionExternal and internal findings are of diagnostic significance Not only as the sole finding Especially when they are found in combination Also true for fatty changes of proximal renal tubulesPathogenesis of alterations caused by hypothermia Hypoxic changes Stress Disturbances of microcirculation 28. Rijen Shrestha